Scapula and Shoulder Joint

The scapula is a large, flat bone of the shoulder which serves as support for the thoracic limb and is attached to the trunk by several large muscle masses. The scapula is located adjacent to the chest wall with extensive muscle mass surrounding it, a configuration that helps to prevent the occurrence of fractures. In one study, the incidence of scapular fractures was reported to be 2.4% of fracture cases treated, with most resulting from vehicular trauma.¹ A retrospective study in 105 cases revealed most scapular fractures occur in young (<4 years of age), male, medium-large (>10kg) dogs.² Because of the increased forces necessary to create such a fracture in this location, a thorough physical, neurologic, and orthopedic exam is necessary to detect other possible concurrent problems such as spinal, skull, brachial plexus injuries, and other musculoskeletal injuries which may influence prognosis. In patients with scapular fractures, approximately two-thirds have concurrent thoracic cavity lesions which include pneumothorax, pneumomediastinum, pulmonary contusions, cardiac arrhythmias, and fractured ribs.¹ Prognosis and treatment options depend on the anatomic location of the fracture which are classified as the body, spine, acromion, neck, supraglenoid tubercle and glenoid of the scapula.^1,3

Diagnosis and Clinical History

Clinical signs on presentation of a scapular fracture vary depending on the location and the severity of the fracture. Signs range from a mild weight bearing lameness to a severely dysfunctional non-weight bearing lameness of the limb. The latter is usually associated with intra-articular fractures of the glenoid and neck fractures that cause the animal to carry the injured leg lower than the opposite limb, with the carpus held in a flexed position or the paw dragging.⁴ Localized pain, swelling, and crepitus on palpation may be present. Comparing findings of palpation of the opposite normal limb with those of the injured limb is valuable when attempting to localize the source of the problem. A thorough history, physical exam, and radiographs are necessary to make a diagnosis.

Radiographs are necessary to confirm the anatomic location and extent of the fracture. Heavy sedation or general anesthesia may be required to position the scapula accurately while also maintaining comfort for the animal. Four views may be necessary to maximize visualization of the entire scapula. Caudocranial views are taken with the animal positioned in dorsal recumbency and the affected limb drawn forward but with the sagittal plane of the thorax rotated 30° away from the affected limb to prevent superimposition of bony densities⁵ (Figure 55-1). The mediolateral view is taken with the animal in lateral recumbency, the affected limb against the film and extended approximately 45° craniad with the opposite limb pulled caudad. The positioning prevents superimposition of the ribs and sternum.⁵ The scapular neck, glenoid, and supraglenoid tubercle are best visualized radiographically with this position but to view the body of the scapula with the mediolateral view, the affected limb should be superimposed over the cranial thorax with the opposite limb pulled craniad instead of caudad.^5-7 The distoproximal (axial) radiographic view may be helpful in visualizing and diagnosing scapular fractures when other views do not. The dog is placed in dorsal recumbency with the elbows extended and the limb pulled caudad and parallel to the table surface. The humerus is at a 90o angle to the scapular spine and the scapula is perpendicular to the table top. The thickness of the tissues is measured at the level of the greater tubercle of the humerus and the beam is centered over the shoulder joint.⁸
 

Treatment Options

Recommended treatment options have not changed significantly over the past 25 years. The healing potential of the scapula is excellent because of the abundance of cancellous bone, the intrinsic support from the musculature, and the abundant contribution of blood supply from the musculature and surrounding soft tissues.⁹ Fractures of the scalpula can be managed either conservatively or with internal fixation. The method chosen depends on the anatomic location and type of fracture. In general, fractures  of the scapula can be managed conservatively except when they involve the articular surface (glenoid), when the fracture results in a distinct change in the angulation of the shoulder joint articulation (displaced scapular neck and body fractures), and when the injury is an avulsion fracture of the acromion and supraglenoid tubercle. Conservatively managed fractures require only limited activity for 3-4 weeks, whereas others may benefit from a modified Velpeau sling or spica splint.³ Support bandages add to the comfort of the animal during the healing period.

Surgical Techniques

Approaches to the scapula, which vary and depend on the anatomic location of the fracture, have been well described and illustrated.¹⁰ Approaches to the scapular neck, glenoid, and supraglenoid tubercle are more difficult and require more advanced surgical skills than approaches to the scapular body. These approaches may include an osteotomy or a muscle separation technique.¹¹ Anatomically, the suprascapular nerve, artery and vein course across the lateral aspect of the scapular neck distal to the acromial process and should be avoided and protected. Damage to the nerve can lead to atrophy of the supraspinatus and infraspinatus muscles.

Scapular Body and Spine Fractures

Fractures that involve the body and spine of the scapula are most often managed conservatively. Limited activity should be advised until a clinical union of the fracture is determined. Because of the abundance of cancellous bone and the inherent support of the fracture by the surrounding musculature along with the presence of an abundant blood supply, healing progresses rapidly, and many animals are clinically normal within 4 weeks, although others may require a longer period of healing.¹ Limitation in activity should be dictated by clinical progression of the animal. The fracture may not be completely healed when clinical function first appears normal; therefore, activity is limited for an additional few weeks. If a modified Velpeau sling is used for immobilization or to provide comfort for the animal, the bandage should be monitored closely and removed in 2-3 weeks to allow for return to normal shoulder joint function and to prevent unwanted contracture of soft tissues and limitations in joint motion.⁴ Fractures that are severely displaced or comminuted or those that change the angle of the normal joint articulation should be repaired with internal fixation. Internal fixation improves the cosmetic result, especially in short-haired dogs, and provides the support necessary for early return to ambulation better function.

Internal fixation of scapular body and spine fractures consists primarily of the use of wires, plates, or a combination of both (Figure 55-2). When placing interfragmentary wires, predrilling the holes and preplacing wires (18, 20, 22 gauge wire) simplifies the procedure. The fractures are then reduced and the wires are tightened. If the spine of the scapula is fractured, tension band wiring may be used. The scapula lacks an abundance of harder cortical bone and care should be taken when tightening the wires so they do not cut through the bone. Minimal fixation can be combined with a Velpeau sling. Interfragmentary wires may be adequate for small dogs and cats, whereas a plate may be required in larger dogs or when angulation displacement is not controlled by wire alone. For plate fixation, the surgeon should place a plate in the angle formed between the junction of the body and the spine and place the screws at an angle for maximum screw purchase in the thickest portion of the bone (Figure 55-2B): Plate placement in the ventral half of the scapula should be along the cranial aspect of the scapular spine/body junction, with screws placed at a 45° angle to the spine. Conversely, a caudal approach should be considered when plating the dorsal half of the scapula.¹² Inverting a semitubular plate and placing it in this location may enhance the fit of the plate to the bone. Cerclage wires placed around the plate may be used in conjunction with the screws for added fixation support of the plate if the screws do not purchase the bone well. Plastic plates may also be placed on both sides of the spine and secured with nuts and screws to provide the support and fixation necessary for preventing angulation and overriding displacement of the fractures (Figure 55-2C). In a mechanical study, when comparing single versus double semitubular plate fixation, single plate fixation of scapular body fractures may be sufficient. Any difference between single and double plating is likely not clinically relevant.¹³ Locking plate technology has the potential to increase stability of the repair in light of the poor bone quality of the scapula.⁵ However, in a scapular fracture model, locking SOP plates were not shown to have a different load to failure than an LC-DCP.¹⁴ Locking plates have not yet been evaluated for scapular fractures in a clinical setting, or in a cyclic load model at the time of this manuscript preparation. Perfect fracture alignment and anatomic reconstruction may not be consistently achieved, but the goal of preventing overriding and angulation of the fracture segments with internal fixation methods is adequate to allow for good functional and cosmetic results.
 

Acromial Fractures

The bony prominence of the distal end of the spine of the scapula, the acromion, is the site at which the acromial head of the deltoid muscle arises and runs distally. The acromion is easily palpable under the skin and can be compared to the opposite limb for asymmetry and identification of a fracture. Fracture of the acromion results in distal displacement created from the pull of the acromial head of the deltoid muscle. The diagnosis can be made with palpation and radiographic findings. The animal typically has a weightbearing lameness and pain is elicited upon palpation. With constant pull from the acromial head of the deltoid, all forms of closed reduction and fixation are inadequate and internal fixation is required.⁴ Typically, one of two methods is used to stabilize the fragment. Either two small pins and a tension band wire can be applied, or two twisted stainless steel interfragmentary wires are placed, depending on the size of the animal and the fragment (Figure 55-3). If the fixation is secure, no additional support is required, limited activity is advised for 6 to 8 weeks, and the prognosis for a complete recovery is good.
 

Scapular Neck Fractures

Animals with scapular neck fractures often present with severe lameness and dysfunction of the limb. If the fracture is not displaced, a spica splint may be applied for immobilization to prevent further displacement. The placement of a Velpeau sling may create stress on the fracture site by creating internal rotation and flexion of the shoulder.⁴ The distal segment often displaces medially and proximally, and closed reduction is difficult. The risk of suprascapular nerve damage is present and the client should be warned of the possibility. As a result, the supraspinatus and infraspinatus muscles may atrophy, leaving a cosmetically altered appearance and impaired function. Internal fixation is recommended to achieve the best result. The suprascapular nerve should be retracted and protected during repair. Many combinations of methods can be used to repair fractures of the neck. Cross-pinning the fracture with Steinman pins or Kirschner wires inserted from the body into the neck is often adequate stabilization for these fast healing fractures (Figure 55-4A and B). The cross pins alternatively can be placed from the supraglenoid tubercle across the neck fracture into the body and the other pin can be inserted from the caudal aspect of the glenoid across the fracture in a similar fashion. In larger breeds, the use of a screw placed in lag fashion or T or L plates can be used to provide more rigid fixation (Figure 55-4C). The technique depends on the size of the animal, nature of the fracture, and the level of exposure created by the surgeon who should be willing to expose as much as necessary to achieve adequate anatomic reduction and stable fixation. Because these methods of fixation are stable, further support is usually not necessary, and with adequate limitation of activity for 6 to 8 weeks, return to normal function is expected.
 

Glenoid Fractures

Fractures of the glenoid are intra-articular (Figure 55-5A). The animal will present with severe lameness and a dysfunctional limb. Palpation reveals an unstable shoulder with crepitus demonstrated when the joint is manipulated. Radiographs are necessary to assess the extent of the fracture. The fracture may involve the cranial half of the glenoid which is most common,¹⁵ or the caudal half of the glenoid; alternatively, both portions may be fractured involving a neck fracture as well (T or Y fracture). (An ununited accessory caudal glenoid ossification center should not be confused with a glenoid fracture, although it may result in variable lameness.¹⁶) The degree of comminution may vary. This fracture requires great external forces, and the possibility of other injuries should be explored. Most patients have concurrent injury to another body region.¹⁵ Brachial plexus injuries and thoracic trauma should be considered. Unless the fracture is so severely comminuted that it cannot be repaired, internal fixation is required. Closed methods of repair are not adequate and should only be considered if the goal is to allow the fractures to heal and later perform an arthrodesis or excision of the humeral head and glenoid as a salvage procedure. A spica splint should be placed with the leg in a more natural functional angle if this option is pursued. Partial scapulectomy is another salvage option, as it has been well described for tumor removal, and there is a single case report of its successful use in treatment of a glenoid fracture.¹⁷ The goal of surgical repair is to expose the surgical site adequately and perfectly reconstruct the alignment of the articular surface of the glenoid to minimize secondary osteoarthritis as a result of incongruence of the articular surface. A combination of pins and screws are used to repair the glenoid first, and if the scapular neck is also fractured, it is repaired with one of the techniques described previously. Depending on the type and location of the fracture segments, various methods of cross pinning, lag screws, and plating may all be used to achieve a congruent and stable fracture repair (Figure 55-5). The prognosis for regaining function of the limb is good but an extended convalescent period can be expected, and most patients will have some degree of continued lameness following fracture repair.¹⁵
 

Supraglenoid Tubercle Fractures

The supraglenoid tubercle is the point of origin of the tendon of the biceps brachii muscle on the cranial portion of the glenoid. The supraglenoid tubercle develops as a separate center of ossification and through endochondral ossification, should fuse to the glenoid by 5 months of age.¹⁸ In the skeletally immature dog, before endochondral ossification is complete, an avulsion fracture may develop through the growth plate and the pull of the biceps brachii muscle distracts the fragment. This type of fracture can occur in the mature animal as well. Utilizing principles of a pin and tension band technique or lag screw fixation can be used successfully to repair the fracture (Figure 55-6). The surgical exposure to accomplish this repair can be challenging. If the fragment is too small, removal may be necessary and the biceps tendon is secured to the proximal humerus creating a tenodesis or it may be released without securing the biceps tendon and allow it to retract without stabilization.
 

Conclusions

All animals identified as having scapular fractures should be examined carefully for concurrent body injuries, specifically cardiopulmonary, neurologic, and other musculoskeletal injuries. Scapular fractures tend to heal rapidly. In general, fractures of the body and spine of the scapula do not require repair if the displacement is minimal and the angulation of the shoulder articulation is not impaired, whereas intra-articular fractures must be properly aligned and stabilized to achieve good long term functional results. Velpeau slings or spica splints can be used to immobilize the fracture and provide comfort for the animal during the early healing period. Fractures of the glenoid, supraglenoid tubercle, acromion, and most neck fractures require internal fixation for best results. Inadequate anatomic reconstruction and instability can result in malalignment of the fractures, nonunion, secondary degenerative joint disease, unsatisfactory cosmetic appearance, and poor limb function. The suprascapular nerve should be retracted and protected during repair of scapular fractures to prevent iatrogenic injury resulting in muscle atrophy and impaired function. The surgeon should be familiar with the anatomy, different surgical approaches, and be willing to achieve the exposure necessary to reconstruct the fractures in a stable and anatomic fashion. Pins, wires, screws and plates provide adequate means for stabilizing scapular fractures.

References

1. Harari, J, Dunning, D: Fractures of the Scapula in Dogs: A Retrospective Review of 12 Cases. Veterinary and Comparative Orthopaedics and Traumatology, 6:105-108, 1993.
2. Cook, JL, Cook CR, Thomlinson JL, et al: Scapular Fractures in Dogs: Epidemiology, classification, and concurrent injuries in 105 cases (1988-1994). J Am Anim Hosp Assoc 1997; 33:528-532.
3. Piermattei, DL, Flo, GL DeCamp, CE: Brinker Piermattei, and Flo’s handbook of Small Animal Orthopedics and Fracture Repair, ed 4, St. Louis, Elsevier, 2006.
4. Newton, CD: Fractures of the Scapula. In Textbook of Small Animal Orthopedics. Edited by CD Newton and DM Nunamaker. Philadelphia, J.B. Lippincott, 1985.
5. Peck, J.: Musculoskeletal System - Scapula. In Veterinary Surgery: Small Animal. Edited by KM Tobias and SA Johnston, St. Louis, Elsevier, 2012.
6. Ticer, JW: Radiographic Technique in Veterinary Practice. Philadelphia, WB Saunders, 1984.
7. Straw, RC: Thoracic Limb - Repair of Scapular Fractures. In Current Techniques in Small Animal Surgery. Edited by MJ Bojrab, Philadelphia, Lea and Febiger, 1990.
8. Roush, JK, Lord, PF: Clinical Application of a Distoproximal (Axial) Radiographic View of the Scapula. J Am Anim Hosp Assoc, 1990; 26(2): 129-132.
9. Brinker, WO, Hohn, RB, and Prieur, WD (eds): Manual of Internal Fixation in Small Animals. New York, Springer-Verlag, 1984.
10. Piermattei, DL, Johnson, KA: An Atlas of Surgical Approaches to the Bones and Joints of the Dog and Cat, ed 4. Philadelphia, Saunders/ Elsevier, 2004.
11. McCartney, WT, Garvan, CB: Muscle separation approach to scapular neck fractures in eight dogs. Veterinary and Comparative Orthopaedics and Traumatology, 5:471-473, 2008.
12. Ocal, MK, Toros, G: A morphometric study on the cross-sections of the scapular spine in dogs. Veterinary and Comparative Orthopaedics and Traumatology, 4:281-284, 2007.
13. Mair, JJ, Belkoff SM, Boudrieau RJ: An Ex Vivo Mechanical Evaluation of Single Versus Double Semitubular Plate Fixation of a Transverse Distal-Third Scapular Osteotomy in the Dog. Vet Surg 2003;32:580-584
14. Acquaviva, AE, Miller, EI, Eisenmann, DJ, Stone, RT, Kraus, KH: Biomechanical testing of locking and nonlocking plates in the canine scapula. J Am Anim Hosp Assoc, 2012; 48: 372-378.
15. Johnston, SA: Articular Fractures of the Scapula in the Dog: A Clinical Retrospective Study of 26 Cases. Journal of the American Animal Hospital Association, 1993; 29(2): 157-164.
16. Olivieri, M, Piras, A, Marcellin-Little, DJ et al: Accessory caudal glenoid ossification centre as possible cause of lameness in nine dogs. Veterinary and Comparative Orthopaedics and Traumatology, 3:131-135, 2004.
17. Plesman, RL, French, S, Nykamp, S, Ringwood, PB: Partial scapulectomy for treatment of an articular fracture of the scapula in a cat. Veterinary and Comparative Orthopaedics and Traumatology, 6:468-473, 2011.
18. Denny, HR: Pectoral Limb Fractures. In Canine Orthopedics. Edited by W.G. Whittick, Philadelphia, Lea and Febiger, 1990.
     

Introduction

Scapulohumeral luxation is an uncommon problem in the dog and rarely occurs in the cat. Luxation is typically the result of traumatic injury or congenital glenoid abnormality. Lateral luxation most commonly occurs in large breed dogs with historical trauma. Medial luxation typically occurs in small dogs with congenital capsular laxity or glenoid dysplasia. Cranial and caudal luxations are documented but occur less frequently than lateral or medial luxation.

Anatomical Considerations and Surgical Approach

It is important to establish a thorough knowledge of anatomy and understanding of anatomical function prior to performing surgical correction for scapulohumeral luxation. Errors in surgical technique are not well tolerated and may contribute to persistent lameness or disability. The following is a brief review of anatomy and surgical approach. A more detailed review of this information is highly recommended for individuals with limited experience in shoulder surgery.

Scapulohumeral stability is the combination of articular stability and soft tissue restraints. The primary soft tissue restraints include the joint capsule and its associated glenohumeral ligaments, and “rotator cuff” tendons. Glenohumeral ligaments are described as thickened regions of the joint capsule and are not grossly apparent from external evaluation (Figure 55-7). However, they are distinct structures when viewed arthroscopically. The medial glenohumeral ligament is “Y” shaped with a cranial and caudal component while the lateral glenohumeral ligament is a wide solitary band that tapers near its insertion. Luxation is not possible without disruption of the joint capsule and its associated glenohumeral ligament. The four “cuff tendons” provide dynamic support with minimal contribution during static conditions. The “cuff tendons” include the supraspinatus cranially, subscapular medially, infraspinatus laterally, and teres minor caudolaterally. Collectively, soft tissue structures are important restraints to joint motion and contribute to joint stability. Identifying injury to such structures is important when selecting methods of stabilization.

A craniomedial approach is most often used for surgical treatment of medial and lateral luxation while a craniolateral approach is performed for cranial luxation. The following craniomedial approach provides general access to the shoulder. Once the shoulder is approached, further dissection varies dependent upon technique and is further described within the relevant section of this chapter. With the patient in dorsal recumbency, a parahumeral incision originating from the medial or cranial aspect of the scapular neck is extended distally to the medial aspect of the humeral mid-diaphysis. Subcutaneous fat is incised exposing the brachiocephalicus muscle. A fascial incision is created the entire length of the lateral border of the brachiocephalicus muscle which requires ligation and division of the omobrachial vein. The brachiocephalicus is elevated and retracted caudomedially while the humerus is externally rotated. The insertion of the superficial pectoral is incised from the humerus along its proximal border to the omobrachial vein.
 

Similary, the deep pectoral muscle is freed from its insertion but requires separation from the overlapping supraspinatus muscle proximally. Both pectoral muscles are retracted medially and the supraspinatus caudolaterally.

Lateral Scapulohumeral Luxation

Lateral luxation commonly presents in large breed dogs with historical trauma. The mechanism is not well defined but is presumably caused by extreme adduction of the limb. Lateral humeral luxation requires tearing of the lateral aspect of the joint capsule, its associated glenohumeral ligament, and infraspinatus tendon.

Diagnosis

Patients present with the forelimb held in flexion and concurrent internal rotation of the foot. The greater tubercle is prominent and displaced laterally. Joint manipulation is painful with overt crepitus. A neurologic examination is indicated to identify concurrent brachial plexus injury. Survey radiographs are performed to confirm the diagnosis and identify concurrent fractures or glenoid rim erosion. Stress radiography may be useful to identify dynamic luxation or subluxation.

Treatment

Closed reduction and splintage is considered in patients with acute injury and mild to moderate joint instability. Under general anesthesia the limb is extended and medial pressure is applied to the humeral head while counter pressure is applied to the scapular neck. Range of motion and joint stability are assessed after reduction and either a spica splint or non-weight bearing carpal sling is maintained for 10 to 14 days. A Velpeau sling is contraindicated for lateral luxation as it applies lateral translation to the humeral head. Results of nonsurgical treatment for lateral luxation are variable and are contingent upon the magnitude of soft tissue disruption, success of splintage, and patient/owner compliance regarding activity restriction. Surgical stabilization should be considered when reluxation is easily elicited.

Surgical intervention is performed for patients with acute unstable injury, concurrent fracture, or chronic luxation. Numerous procedures are described including prosthetic ligament reconstruction, biceps tendon transposition, transarticular pinning, glenoid excisional arthroplasty, and arthrodesis. The method of repair is based upon etiology of luxation, concurrent fracture, or the ability to restore glenoid integrity if a fracture is present. The advantages and disadvantages of each technique should be considered in relationship to patient signalment, health status, and patient compliance.

Lateral transposition of the biceps tendon is the most documented technique in the literature and is the preferred method of repair when patient variables are appropriate (Figure 55-8). A craniomedial approach is used for biceps transposition. Once the pectoral muscles are retracted medially and the supraspinatus caudolaterally, the transverse humeral ligament is incised and the biceps tendon is freed from regional fascial and capsular tissue. The greater tubercle is osteotomized to allow lateral transfer of the biceps tendon over the cut surface of the greater tubercle. The tubercle is reattached with a screw or pin and tension band apparatus. The joint capsule is closed with absorbable suture and the pectoral muscles are apposed to deltoid fascia. Remaining fascia, subcutaneous fat and skin are routinely closed. Seroma formation is common in this area and may be avoided with careful implant technique, tissue apposition, and postoperative recovery. Strict activity restriction and confinement are required for 2 to 3 weeks. Passive range of motion may be performed in the initial recovery period. Short controlled leash walks begin 2 weeks postoperatively followed by a gradual return to full function over an additional 6 to 12 weeks.
 

Prognosis and Complications

Normal return to function and full range of motion has been reported with long-term evaluation of this technique. Mild distortion of joint congruity is common at the time of repair but resolves as weightbearing forces cause stretching and relaxation of the tendon. Progression of osteoarthrosis is expected and the biceps tendon is at risk for midsubstance tearing in the future. In spite of such adverse effects, the technique is still recommended as excellent clinical function is the most commonly reported outcome. This technique is less successful in patients with chronic luxation or glenoid dysplasia; in which case arthrodesis or glenoid excisional arthroplasty should be considered.

Medial Scapulohumeral Luxation

Medial luxation is more common than lateral and is reported in small and large breed dogs. Medial luxation in large breed dogs is typically associated with trauma while congenital luxation is more common in small breed dogs. Congenital luxation may be bilateral and is associated with developmental laxity or glenoid dysplasia which is difficult and potentially impossible to correct.

Diagnosis

The historical presentation and physical examination findings vary depending upon the etiology for luxation. Traumatically induced medial luxation presents with an acute persistent lameness with the affected limb held in flexion with external rotation of the foot. Joint manipulation is typically painful during extension and medial displacement of the greater tubercle.

In contrast, congenital luxation may present with intermittent to continuous lameness and joint manipulation is often well tolerated. Mild to moderately dysplastic luxations are often easily reduced and reluxated. More severely dysplastic luxations are commonly non-weightbearing, pain is variable, and joint reduction is difficult.

Radiographic evaluation of traumatically induced medial luxation is scrutinized for concurrent glenoid fracture. Congenital luxation is carefully evaluated for hypoplastic glenoid development and erosion of the medial glenoid rim. Stress radiography should be considered to document luxation in patients with intermittent lameness.

Treatment

Conservative management for medial luxation is contraindicated when glenoid dysplasia is present. However, conservative management is considered for traumatically induced medial luxation when reasonable joint stability is achieved following closed reduction. Closed reduction is performed under general anesthesia with the patient in lateral recumbency and the limb in a neutral standing position. Traction and slight adduction are initiated while lateral pressure is applied to the proximal medial humerus and counter pressure is applied to the scapular neck. A Velpeau sling is ideal stabilization for medial luxation as it eliminates weightbearing and compresses the humeral head laterally. The Velpeau sling is maintained for 2 weeks followed by careful gradual return to function over 4 to 8 weeks.

Surgical techniques reported for medial luxation include prosthetic collateral suture, supraspinatus transposition, transarticular pinning, medial biceps transposition, arthrodesis, excisional arthroplasty, and amputation. Choosing a method of repair is based upon glenoid conformation, concurrent injury, patient size and chronicity of luxation.

In patients with acute traumatic luxation without glenoid dysplasia; medial transposition of the biceps tendon is the preferred technique (Figure 55-9). A craniomedial approach is performed and once the pectoral muscles are reflected, the leg is externally rotated to access the subscapularis muscle. The insertion of the subscapularis is incised allowing caudal retraction of the subscapularis and coracobrachialis while the biceps tendon is freed by incising the transverse humeral ligament and regional capsular attachments. At the lesser tubercle, a craniodorsal hinged flap of bone is created with a crescent-shaped osteotomy. Cancellous bone is removed beneath the flap to accommodate transposition of the biceps tendon. Once the luxation is reduced, the biceps tendon is transferred and secured into the preformed groove by reattaching the bone flap with Kirschner wires. Medial capsular imbrication is performed with absorbable suture and the subscapularis is advanced and attached to the insertion of the deep pectoral muscle. The pectoral muscles are secured to the deltoid and deep brachial fascia. The brachiocephalic muscle is sutured to brachial fascia. The remaining fascial, subcutaneous and skin layers are closed separately. The repair is supported with a Velpeau sling for 7 to 10 days followed by gradual return to function over 4 weeks.
 

An alternative to biceps transposition is prosthetic collateral repair. It is less time consuming, less invasive, and simpler to perform. The technique is not appropriate for large dogs but should be considered for acute traumatic luxation in small dogs without glenoid dysplasia. The technique is performed using a standard craniolateral approach with tenotomy of the infraspinatus tendon. A curved incision starts at the distal third of the scapular spine extending distally across the joint craniolaterally to the mid-diaphysis of the humerus. Subcutaneous fat and fascia are dissected and the deep brachial fascia is incised from the cranial aspect of the acromion process extending distally along the cranial border of the acromial part of the deltoid muscle. The deltoid is retracted caudally allowing transaction of the infraspinatus tendon which is reflected dorsally. The joint capsule is incised transversely and intra-articular structures are inspected. The joint capsule is closed and a hole is drilled from lateral to medial through the center of the humeral neck. A similar hole is drilled in the center of the scapular neck paying careful attention to protect the suprascapular nerve. Suture is passed from lateral to medial through the scapular bone tunnel and medial to lateral in the humeral tunnel (Figure 55-10). External rotation of the limb and retraction of the brachiocephalic and pectoral muscles medially is required to expose the medial aspects of the humerus and scapular neck for suture advancement. The joint is reduced, suture is tied in moderate tension, and joint mobility and stability are assessed. This technique reported using double strands of 0 or number 1 monofilament polybutester for its elastic properties. The infraspinatus tendon is reattached and routine closure is performed. The repair is supported with a Velpeau sling for 14 to 21 days followed by 4 weeks of passive range of motion and gradual rehabilitation.
 

If the biceps tendon is damaged or if previous repair is unsuccessful, partial supraspinatus transposition may be considered (Figure 55-11). The approach is identical to the biceps transposition technique, however, the biceps tendon and transverse humeral ligament are repaired and medial capsular imbrication is performed. The greater tubercle is osteotomized such that the superficial one-half of the supraspinatus tendon is released. The insertion of the subscapularis muscle is incised and a recipient site of exposed cancellous bone is created at the lesser tubercle with a burr, rasp, or osteotome. The supraspinatus is divided only to the extent that the oseotomized tubercle may reach the recipient site with moderate tension. Recurrence of luxation is contingent upon proper tension in the transferred component of the supraspinatus tendon. The transferred tubercle is stabilized with multiple Kirschner pins or pin and tension band. The subscapularis is advanced to the pectoral insertion and pectoral muscles are attached as far cranial as possible to augment medial support of the shoulder. Remaining layers are closed separately. A Velpeau sling is maintained for 7 to 10 days followed by gradual return to function.
 

Arthrodesis is indicated for patients following failed attempts at surgical repair or in patients with significant glenoid dysplasia or degenerative joint disease. Standard principles of arthrodesis apply to the shoulder. In small dogs, a single screw through the scapular neck and into the humerus combined with a spica splint may be adequate for stabilization. Large dogs typically require bone plate application along the scapular spine and proximal humerus. More detailed information is covered in the arthrodesis section of this chapter.

Excisional glenoid arthroplasty has been described as an alternative to arthrodesis. Excisional arthroplasty may achieve pain-free movement with limited compromise of limb length and joint motion. More detailed information is covered in the excisional glenoid arthroplasty section of this chapter.

Amputation is reserved as a salvage procedure for patients with multiple failed surgical correction, severe glenoid dysplasia, or severe degenerative joint disease. Amputation may not be appropriate for giant breed dogs. Candidates for amputation should be carefully assessed for congenital or traumatic contralateral limb abnormalities.

Prognosis and Complications

Prognosis after medial biceps transposition is variable. The majority of dogs are expected to achieve satisfactory limb function; however, intermittent to persistent lameness occurs is approximately 50% of cases. Similar to lateral biceps tendon transfer, transient joint incongruity, osteoarthrosis, and midsubstance biceps tendon tearing have been reported for medial transfer of the biceps tendon. In general, experience with this technique is favorable.

Full return of limb function was reported in dogs 2 to 3 months following collateral prosthetic ligament reconstruction with polybutester suture. This is the authors preferred technique provided case selection is limited to small dogs without preexisting joint abnormalities. There are no reports of this technique in cats, however; intuitively, this technique may provide similar favorable results.

Prognosis of partial supraspinatus tendon transfer is limited to a single case report describing normal function and full range of motion 2 months following surgery. Adverse effects of joint incongruity and tendon tearing are less apt to occur but further study has not been performed.

Reports of shoulder arthrodesis are generally favorable due to mobility of the scapula. Best results are seen in small dogs, whereas, large dogs have a varied outcome and more apparent gait abnormality.

Excisional glenoid arthroplasty was reported to achieve good to excellent results in one study. This technique is limited to patients with severe glenoid dysplasia or degenerative joint disease. Clients should be informed that mild reduction in joint mobility, muscle atrophy, and limb shortening are expected.

Cranial and Caudal Luxation

Cranial and caudal scapulohumeral luxation are rare. Reports in the veterinary literature are limited to a few case reports. Etiology of cranial and caudal luxation appears to be associated with trauma. The only described technique for cranial luxation is transfer of the biceps tendon cranially into a groove within the greater tubercle (Figure 55-12). A craniolateral approach is performed and the greater tubercle is osteotomized. A groove is made into the cut surface of the osteotomy. The transverse humeral ligament is incised and the biceps tendon is mobilized into the preformed groove. The capsular tissue is imbricated and the greater tubercle is reattached with pins and tension band apparatus. Standard closure is performed and a spica splint is maintained for 10 days.

Caudal luxation has been treated with caudal and lateral imbrication in combination with a non-weightbearing sling for 10 days.
 

Prognosis is difficult to predict as no long-term studies have evaluated cranial or caudal luxation repair. Limb function is presumed to be satisfactory but further study is needed.

Suggested Readings

Ball DC: A case of medial luxation of the canine shoulder joint and its surgical correction. Vet Rec 83:195, 1968.

Bardet JF: Lesions of the biceps tendon diagnosis and classification. Vet Comp Orthop Traumatol 13:188, 1999.

Craig E, et al: Surgical stabilization of traumatic medial shoulder dislocation. J Am Anim Hosp Assoc 16:93, 1980.

Craig E, et al: Treatment of shoulder joint luxations. In Bojrab MJ (ed): Current Techniques in Small Animal Surgery, 3rd ed. Lea & Febiger, Philadelphia, 1990, p 740.

DeAngelis MP: Luxations of the shoulder. In Bojrab MJ (ed): Current Techniques in Small Animal Surgery, Lea & Febiger, Philadelphia, 1975, p 499.

DeAngelis MP, Schwartz A: Surgical correction of the cranial dislocation of the scapulohumeral joint in the dog. J Am Vet Med Assoc 156:435, 1970.

Evans HE, Christensen GC: Miller’s Anatomy of the Dog, 2nd ed. WB Saunders, Philadelphia, 1979, p 240.

Fowler D, et al: Scapulohumeral arthrodesis: Results in seven dogs. J Am Anim Hosp Assoc 24:667, 1988.

Franczuski D, Parks LJ: Glenoid excision as a treatment in chronic shoulder disabilities: Surgical technique and clinical results. J Am Anim Hosp Assoc 24:637, 1988.

Herron MR: Scapulohumeral arthrodesis: An evaluation of two techniques in 33 cases [abstract] Vet Surg 18:78, 1989.

Piermattei DL, Blass CE: Resection of the glenoid rim and humeral head. In Bojrab MJ (ed): Current Techniques in Small Animal Surgery. 3rd ed. Lea & Febiger, Philadelphia, 1990, p 748.

Piermattei DL, Greeley RG: An Atlas of Surgical Approaches to the Bones of the Dog and Cat, 2nd ed. WB Saunders, Philadelphia, 1979, p 72.

Prostredny JM, et al: Use of polybutester suture to repair medial scapulohumeral luxation in the dog: Three cases. J Am Anim Hosp Assoc 29:180, 1993.

Vasseur PB: Clinical results of surgical correction of shoulder luxation in dogs. J Am Vet Med Assoc 182:503, 1983.

Vasseur PB: Effects of tendon transfer on the scapulohumeral joint. Am J Vet Res 44:811, 1983.

Vasseur PB, et al: Stability of the canine shoulder joint: An in vitro analysis. Am J Vet Res 43:352, 1982.
 

Introduction

Treatment of osteochondritis dissecans (OCD) of the shoulder joint involves removal of all loose and damaged fragments of cartilage and bone from all aspects of the joint. OCD lesions in the shoulder almost always occur on the caudal aspect of the humeral head. Loose fragments of cartilage can migrate into the caudal cul-de-sac of the joint and/or into the cranial bicipital tendon sheath. There is no effective surgical approach to both areas, so dealing with each area requires two separate approaches. Consequently, I usually recommend doing an arthrogram prior to surgery to determine whether or not the bicipital tendon sheath needs to be explored. Arthroscopy can also be used.

Surgical management of OCD of the caudal humeral head involves removal of all loose cartilage with a sharp curette so that no cartilage remains elevated and unattached to underlying bone. The removal and curettage of damaged bone and cartilage will decrease pain and inflammation resulting from irritation and impingement of the joint capsule and other joint elements. Exposed subchondral bone is curetted to bleeding surfaces so that the resultant defect can be resurfaced with new fibrocartilage. If any cartilage is left unattached to subchondral bone, it may fragment and produce loose bodies in the joint. Loose cartilage is unlikely to re-attach to the underlying bone.

This caudal approach to the shoulder joint allows excellent visualization of, and access to, the caudal humeral head and both the medial and lateral aspects of the caudal joint cul-de- sac. It is primarily a muscle-separating approach. No tendons are incised, so recovery is rapid with minimal post-operative complications.

Surgical Technique

The patient is placed in lateral recumbency with the affected leg in an upward position and hung so it can be completely draped and be free for extensive manipulation during surgery. The location of the skin incision is identified by connecting the midpoint of the scapular spine with the midpoint of the humerus (Figure 55-13). The skin, subcutaneous tissue, and superficial fascia are retracted to expose a whitish linear fascial raphe between the spinous (or scapular) head of the deltoid muscle and the long head of the triceps muscles (Figures 55-14 and 55-15). This fibrous raphe is incised either bluntly or sharply. Blunt dissection between these two muscles is continued until the caudal shoulder joint capsule is identified (Figures 55-16 and 55-17). It is easier to start the blunt separation digitally between the spinous (scapular) head of the deltoid muscle and the long head of the triceps muscle slightly above the level of the caudal shoulder joint and proceed in a cranioventral direction than to begin the blunt dissection from below the caudal shoulder joint and proceed in a craniodorsal direction. Thus the surgeon does not have to deal with the lateral head of the triceps muscle (See Figure 55-14). The few small muscular branch vessels encountered are either retracted or ligated. A self-retaining retractor is used to maintain separation of the spinous (scapular) head of the deltoid and the long head of the triceps muscles (Figure 55-18). The teres minor is seen crossing the dorsal aspect of the caudal joint capsule (Figures 55-19 and 55-20). The axillary nerve is identified as it crosses the ventral aspect of the caudal joint capsule (Figures 55-21 and 55-22). An incision into the joint capsule is made transversely (perpendicular to the long axis of the humerus) between and parallel to, the teres minor muscle and the axillary nerve (Figure 55-23). This incision exposes the caudal glenoid, caudal humeral head, and caudal joint cul-de-sac (Figure 55-24). Another self-retaining retractor may be used here to retract the cut edges of the joint capsule if desired (See Figure 55-18).

A lesion of osteochondritis dissecans can be identified and treated (Figure 55-25). Manipulation of the leg by an assistant aids in identifying the full extent of the lesion (Figure 55-26). The caudal cul-de-sac can be examined and flushed (Figure 55-27).

The caudal shoulder joint capsular incision is closed with a horizontal mattress absorbable suture (Figure 55-28). The fasciae of the spinous (or scapular) head of the deltoid and the long head of the triceps muscles are reapposed with simple continuous absorbable suture (Figure 55-29). The subcutaneous and skin closures are routine (Figure 55-30). Restricted activity is allowed for the first two weeks postoperatively. Slings and splints are not necessary nor are they advised.
 

Summary and Results

This surgical approach to the caudal shoulder joint offers a number of advantages to other surgical approaches. It is primarily a muscle-separating approach where no tendons or ligaments are incised. It offers excellent visualization of the caudal humeral head and caudal joint cul-de-sac. The skin and the joint capsule are the only tissues sharply incised. This approach offers a less traumatic, less time consuming, and more effective way to manage shoulder OCD. There is no resultant loss of range of motion of the shoulder joint with this procedure. It offers good visualization of the joint (albeit not as exquisite as can be seen with arthroscopy) and recovery is remarkably comfortable and rapid in most patients. The caudomedial joint can be explored via this approach, an area unavailable via a caudolateral approach. In addition, the vascular and neural plexuses are easier to retract and avoid in the caudal approach than in the caudolateral approaches.

Complications are minimal. Seroma formation is extremely rare. Some manipulation of the leg is necessary to fully identify the full extent of some lesions of OCD on the caudal humeral head, but this has not ever precluded visualization of the entire extent of the lesion at surgery. The facts that the surgery can be performed quickly and relatively comfortably makes this approach an excellent alternative to the more time-intensive use of arthroscopy. Closure is quick and simple and patients usually return to near normal activity within days after surgery.

Suggested Readings

Gahring, DR: A modified caudal approach to the canine shoulder joint. J Am Anim Hosp Assoc 21:613, 1985.

Gahring, DR: Surgical Treatment of Osteochondritis Dissecans of the Shoulder. In: Bojrab, MJ, ed.: Current Techniques in Small Animal Surgery, 4th Ed. Baltimore: Williams & Wilkins 1998, p 1069.
 

This topic is written based on the available literature through 2010 and does not cover the most current literature on this topic.

Background

Injury or insult to the biceps tendon has been reported as a frequent cause of forelimb lameness in dogs that typically requires treatment.^1-9 Reported pathologic conditions of the biceps tendon include tenosynovitis, partial or complete rupture, avulsion, tendinitis, tendinosis, displacement, and bipartite tendon. The pathology, epidemiology, and diagnostics associated with these conditions have been described.^1-9 Biceps tendon injuries occur most commonly in middle-aged medium and large breed dogs that participate in athletic activities. There is no documented gender predisposition to the author’s knowledge. Apart from rupture or avulsion, dogs with biceps tendon pathology are presented for a unilateral forelimb lameness of insidious onset. Dogs are typically weightbearing on the affected limb. Rupture or avulsion may result in a lameness that is acute and more severe.

Diagnostics

Physical examination findings in dogs with biceps tendon pathology are very similar regardless of the specific cause. The most consistent findings include mild to moderate atrophy of the affected spinatus muscles, pain on shoulder flexion (especially with the elbow extended), and pain on direct palpation of the biceps tendon and/or manual tensioning of the biceps muscle.^1-6,23

Definitive diagnosis and characterization of the type of pathology of the biceps tendon typically require more advanced imaging modalities such as contrast arthrography, ultrasonographic evaluation and/or arthroscopic visualization. Plain radiographic views of the affected shoulder joint provide relevant information regarding secondary bone and soft tissue changes and should be included in the diagnostic database. “Skyline” radiographic views may aid in evaluating the biceps groove.^3,7 In cases of bicipital tenosynovitis, radiographs may show evidence of osteophytosis and enthesiophytosis associated with the biceps tendon and groove (Figure 55-31). Contrast arthrography provides additional information regarding the anatomy and integrity of the biceps tendon. Contrast arthrography is reported to be sensitive for identifying biceps tenosynovitis,⁷ but generally does not delineate type or extent of the pathology or give information regarding changes within the tendon tissue.^1-3,7-9 Ultrasonography of the biceps tendon, performed by an experienced individual, provides for assessment of intratendinous pathology, associated effusion, and pathologic changes of the biceps groove (Figure 55-32).^5,7,21 Ultrasonography is helpful for determining the type and severity of the pathology in the majority of cases. Arthroscopic evaluation of the shoulder joint allows for visualization and assessment of all intra-articular structures providing definitive evidence of visible biceps pathology as well as involvement of other tissues (Figure 55-33). Techniques for exploratory arthroscopy of the shoulder joint of dogs have been previously described.^{4,5,10,21,22,23} Arthroscopic evaluation of the shoulder joint is recommended as the diagnostic modality of choice as it allows for visualization, “palpation”, biopsy, and when necessary, treatment, of pathology. More advanced imaging techniques such as computed tomography and magnetic resonance imaging are currently being investigated for their usefulness for diagnosis of shoulder joint pathology in dogs.^19,26,28
 

It is critical to perform a comprehensive diagnostic evaluation of dogs suspected, or even confirmed, to have biceps tendon pathology. Biceps tendon pathology can be a secondary or incidental finding. Many dogs with biceps tendon problems will also have elbow pathology, neurologic dysfunction, or neoplasia. In addition, the biceps tendons of insertion may be a primary or additional source of pain in these cases.^24,28 It is vital to look for other pathology in every dog diagnosed with biceps tendon disorders as these other problems are often more clinically important and will greatly affect treatment and prognosis. Complete neurologic examination and radiographs of the elbows are recommended in all cases.

Surgical Treatment

When biceps tendon pathology is determined to be a significant cause of pain, lameness, and/or dysfunction in dogs, treatment is indicated. Non-surgical management of biceps tendon pathology consisting of activity modification, non-steroidal anti-inflammatory drugs, analgesics, and/or intra-articular injections may be effective in many cases.^1-3,8,22 However, surgical management often becomes necessary in a significant number of these patients.^1-5,8 The reported surgical treatment options for biceps tendon disease include tenodesis, tenotomy, primary repair, debridement, transposition, and lavage.^1-5,8 Primary repair, debridement, and transposition are rarely indicated for primary lesions of the biceps tendon and will not be addressed further in this chapter. Based on the published veterinary literature, biceps tenodesis via an open approach and open or arthroscopic biceps tendon release (tenotomy) are the most common surgical procedures used to treat biceps tendon problems in dogs.^{1- 4,8,20} Arthroscopic tenodesis has also been reported to be a successful means of treatment for biceps disorders in dogs.⁵

Tenotomy

Open tenotomy is performed through a modified cranial approach to the shoulder joint.¹¹ After incision of the skin over the cranial aspect of the distal scapula and medial aspect of the greater tubercle, the supraglenoid tubercle can be palpated proximal to the pectoral muscles. The fascia and joint capsule over the supraglenoid tubercle can be incised taking care to avoid the suprascapular nerve and associated vessels proximally. The biceps tendon can then be visualized and tenotomized at its origin using a scalpel blade, scissors, or other appropriate cutting device. Routine closure of the joint capsule, fascia, subcutaneous tissues, and skin is performed.

For arthroscopic tenotomy,⁴ a caudolateral camera portal and craniolateral instrument portal are used.¹⁰ Complete arthroscopic assessment of the joint is performed, and the biceps tendon is identified and assessed. The biceps tendon is tenotomized at its origin using a scalpel blade (beaver blade or #11 blade), arthroscopic scissors or basket forceps, a motorized shaver, radiofrequency, or electrosurgical device placed through the instrument portal (Figure 55-34). The skin incisions are closed routinely.
 

Tenodesis³

After performing a cranial approach to the shoulder,¹¹ the biceps tendon is visualized and detached from its origin on the supraglenoid tubercle. The tendon is then transposed laterally and fixed to the proximal humerus in one of three ways: 1) the tendon can be passed from medial to lateral through a hole drilled through the greater tubercle that is large enough to accommodate the diameter of the tendon and then sutured to the periosteum laterally and medially; 2) the greater tubercle can be osteotomized, the tendon placed at the site of osteotomy and the tubercle reattached over the tendon using a tension band wire technique; or 3) a longitudinal incision is made in the biceps tendon, a cancellous bone screw with spiked washer is placed through the incision and into the bone to attach the tendon at its transposed location. The elbow is held in extension and adequate length of tendon ensured prior to fixation. Routine closure of the joint capsule, muscle and fascia, subcutaneous tissues, and skin is performed. Postoperative radiographs should be obtained in all cases.

Arthroscopic Tenodesis⁵

The technique is performed using a caudolateral camera portal and two instrument portals (i.e., craniolateral and cranial) (Figure 55-35). The arthroscope is inserted and the joint thoroughly evaluated for pathology of all relevant structures. The biceps tendon is identified and a 16-gauge spinal needle, or other suture-passing device, inserted through the craniolateral portal and through the biceps tendon at its proximal aspect. Suture (#2 braided polyblend suture (FiberWire suture, Arthrex, Naples, FL 34104) or 0 polypropylene suture (0 Prolene, Ethicon, Somerville, NJ 08876) with the needle removed) is passed through the tendon. The suture-passing device is removed, and both ends of the suture are grasped through the cranial portal and pulled through the skin using arthroscopic grasping forceps. The suture ends are clamped with a mosquito forceps. The biceps tendon is then released at its attachment of origin on the supraglenoid tubercle using a basket forceps, scalpel blade, motorized shaver, or other cutting device (Figure 55-36). An intramedullary pin is then inserted through the cranial portal to locate the point of drilling for tendon fixation insertion. The point of fixation placement should be the most distal point in the biceps groove that is visible arthroscopically with the shoulder held at a weight bearing angle (approximately 110 to 130°). The appropriate drill sleeve for the intended fixation device is then inserted over the pin. The pin is removed and the appropriate drill bit inserted through the drill sleeve and used to drill a hole through the cis cortex of the proximal humerus. The drill bit and sleeve are removed and the fixation device is inserted and tightened to fix the tendon to the proximal humerus (Figure 55-37). It is imperative that the elbow be held in extension and that adequate tendon length is verified prior to insertion of the fixation device. At least two different devices can be used for fixation. When using the Arthrex^® Biceps Tenodesis 5.5 mm non-absorbable cannulated interference screw system (Bio-Tenodesis System, Arthrex, Naples, FL 34104), the suture in the tendon is pulled through the cannulated screw using the driver. The screw is inserted into the hole pulling the tendon with it, and the screw is tightened until it is flush with the bone (Figure 55-38). A 3.0 mm cannulated screw (3.0 mm cannulated screw, Synthes, Monument, CO 80132) and tissue washer (spiked washer, Synthes, Monument, CO 80132) can also be employed effectively (Figure 55-39). When using the cannulated screw and washer, the cannulation wire is placed through the tendon at the level of the suture. The drill bit is then inserted over the wire and the hole is drilled. The cannulated screw with washer is then driven through the tendon into the hole and tightened until the washer firmly engages the tendon and contacts the underlying bone. Again, the elbow should be held in extension during final screw insertion. The skin incisions are closed routinely and postoperative radiographs are taken.
 

Postoperative Care

For open tenodesis cases, home care instructions included 10 to 15 minute walks 3 to 4 times a day, and ice packing the surgery site for 5 to 10 minutes twice daily. Jumping, running, or off leash activity were prohibited for 2 weeks. The use of a Velpeau sling for 10 days and restriction of exercise to on-leash activities for 6 to 8 weeks following open tenodesis has been recommended.³

For arthroscopic tenodesis cases, clients are instructed to allow short leash walks only, and to restrict the dog to a cage, crate, or kennel when unobserved. These restrictions apply to the first 6 weeks after surgery. If the dog can bear weight on the operated limb with no evidence of pain or displacement of the biceps muscle, and no evidence of implant failure is present at the 6 week recheck, a progressive return to full activity is encouraged over the subsequent 6 weeks. Range-of-motion exercises and non-concussive activities such as swimming and leash walking are encouraged during the second 6 week period. Full, unrestricted activity is allowed after 12 weeks of rehabilitation. Additional restrictions and rehabilitation modalities are tailored to each individual case.^4,25

Complications

If osteoarthritis is present in the affected joint at the time of surgery, progression is likely regardless of the surgical technique employed. For arthroscopic tenotomy cases, reported complications include progression of radiographic pathology, continued pain and lameness and/or recurrence of pain and lameness.^4,20 Other complications that have been associated with open or arthroscopic tenotomy include seroma formation, change in appearance of the brachial musculature, and infection.

In cases of open tenodesis, delayed union of the tubercle osteotomy, implant migration, and seroma formation have been reported.³ In the published report on arthroscopic tenodesis, seroma formation was the only reported complication.⁵ No biceps muscle displacement or laxity was reported for any of the tenodesis cases following surgery.

Prognosis

For arthroscopic biceps tenotomy for treatment of bicipital tenosynovitis, good to excellent results were obtained in all five dogs in one series based on subjective measures over a 6 month follow-up period.⁴ In another series of cases, excellent outcomes were reported for 22 of 25 shoulders assessed of a mean of 26 months postoperatively.²⁰

Open tenodesis has been associated with good and excellent outcomes in more than 90% of dogs treated.^3,8 In the single published report on arthroscopic tenodesis, all 6 dogs treated were judged to have good or excellent outcomes according to the owners.⁵ Owners reported that full return to function was typically evident by 12 to 18 weeks after surgery. Follow-up times range from 5 months to 18 months (mean = 11.7 months, median = 12.5 months). Return of spinatus and brachial muscle mass symmetry and resolution of lameness were evident in all cases based on subjective evaluation by the surgeon.

The published literature regarding surgical treatment of biceps tendon pathology suggests that weight management and physical rehabilitation are critical for a successful outcome when treating biceps tendon problems using any modality.^1-5,8 In addition, maximal function may not be reached until 6 months following surgery in the majority of cases.

Summary

Both tenotomy and tenodesis are used in people for treatment of biceps tendon pathology.^12-18 Indications and recommendations for tenotomy versus tenodesis vary among types of pathology; patient age; activity level and expectations; and surgeons’ preferences.^12-18 Good and excellent results have been reported for both tenodesis and tenotomy in people, and many surgeons recommend achieving competence in both techniques to provide comprehensive treatment options and patient care.^14-18 Tenotomy has been reported to provide similar outcomes in terms of cosmetic appearance, anterior shoulder pain, and degree of muscle spasms in humans with chronic bicipital pain.¹⁴ However, to the authors’ knowledge, no studies have compared functional outcomes of arthroscopic biceps tenotomy versus tenodesis in terms of limb strength and activity levels in the human or veterinary literature. Tenodesis is typically recommended over tenotomy in athletic people, especially those who participate in overhead athletic activities.^16-18 Similarly, athletic dogs may benefit from tenodesis when compared to tenotomy. In addition, since dogs have the added function of weight bearing in the forelimb, tenodesis might be advantageous for dogs. This consideration was supported by the excellent long-term results of open biceps tenodesis reported by Stobie, et al.³ The theoretical advantages of tenodesis may be further optimized by employing an all-arthroscopic technique in order to minimize soft tissue disruption and the associated pain, morbidity, complications, and recovery time. While arthroscopic tenodesis is technically demanding, repetition and experience allow for more efficient and precise implementation of the procedure. The technical demands, surgical time, and costs associated with arthroscopic tenodesis far exceed those for tenotomy. However, the indications, as well as the long-term outcomes, of arthroscopic biceps tenotomy versus tenodesis have not been determined in dogs. Therefore, it is important to explore the feasibility and results of both techniques until definitive conclusions regarding their efficacy can be drawn from scientific data. Long-term studies are needed to determine the effects of arthroscopic tenotomy versus tenodesis on muscle, elbow, and limb function before definitive recommendations regarding indications, complications, and prognosis can be made.

References

1. Bardet JF. Shoulder diseases in dogs. Vet Med Dec: 909, 2002.
2. Bardet JF. Lesions of the biceps tendon – diagnosis and classification. Vet Comp Orthop Traumatol 12: 188, 1999.
3. Stobiie D, Wallace LJ, Lipowitz AJ, et al: Chronic bicipital tenosynovitis in dogs: 29 cases (1985 – 1992). J Am Vet Med Assoc 207: 201, 1995.
4. Wall CR, Taylor R: Arthroscopic biceps brachii tenotomy as a treatment for canine bicipital tenosynovitis. J Am Anim Hosp Assoc 38: 169, 2002.
5. Cook JL, Kenter K, Fox DB: Arthroscopic biceps tenodesis: Technique and results in six dogs. J Am Anim Hosp Assoc 41: 121, 2005.
6. Gilley RS, Wallace LJ, Hayden DW: Clinical and pathologic analyses of bicipital tenosynovitis in dogs. Am J Vet Res 63: 402, 2002.
7. Rivers B, Wallace L, Johnston GR: Biceps tenosynovitis in the dog: Radiographic and sonographic findings. Vet Comp Orthop Traumatol 5:51, 1992.
8. Lincoln JD, Potter K: Tenosynovitis of the biceps brachii tendon in dogs. J Am Anim Hosp Assoc 20: 385, 1984.
9. Davidson EB, Griffey SM, Vasseur PB, et al: Histopathologic, radiographic and arthrographic comparison of the biceps tendon in normal dogs and dogs with biceps tenosynovitis. J Am Anim Hosp Assoc 36 – 522, 2000.
10. Beale BS, Hulse DA, Schulz KS, Whitney WO: Small Animal arthroscopy. Philadelphia: Saunders, 2003.
11. Piermattei DL: An Atlas of Surgical Approaches to the Bones and Joints of the Dog and Cat. Philadelphia: Saunders, 1993.
12. Kleps S, Hazrati Y, Flatow E: Arthroscopic biceps tenodesis. Arthroscopy 18: 1040, 2002.
13. Boileau P, Krishnan SG, Costa JS, et al: Arthroscopic diceps tenodesis: A new technique using bioabsorbable interference screw fixation. Artrhsocopy 18: 1002, 2002.
14. Osbahr DC, Diamond AB, Speer KP: The cosmetic appearance of the biceps muscle after long-head tenotomy versus tenodesis. Arthroscopy 18:483, 2002.
15. Gill TJ, McIrvin E, Mair SD, et al. Results of biceps tenotomy for treatment of pathology of the long head of the biceps brachii. J Shoulder Elbow Surg 2001; 10: 247 – 249.
16. Berlemann U, Bayley I. Tendonitis of the long head of biceps brachii in the painful shoulder: improving results in the long term. J Shoulder Elbow Surg 1995; 4: 429 – 435.
17. Sethi N, Wright R, Yamaguchi K. Disorders of the long head of the biceps tendon. J Shoulder Elbow Surg 1999; 8: 644 – 654.
18. Patton WC, McCluskey GM. Biceps tendinitis and subluxation. Clin Sports Med 2001; 20: 505 -529.
19. Agnello KA, Puchalski SM, Wisner ER, Schulz KS Kapatkin AS. Effect of positioning, scan plane, and arthrography on visibility of periarticular canine shoulder soft tissue structures on magnetic resonance images. Vet Radiol Ultrasound. 2008 Nov – Dec; 49(6): 529 -539.
20. Bergenhuyzen AL, Vermote KA, van Bree H, Van Ryssen B. Long-term follow-up after arthroscopic tenotomy for partial rupture of the biceps brachii tendon. Vet Comp Orthop Traumatol. 2010; 23(1): 51 – 5.
21. Cogar SM, Cook CR, Curry SL, Grandis A, Cook JL. Prospective evaluation of techniques for differentiating shoulder pathology as a source of forelimb lameness in medium and large breed dogs. Vet Surg. 2008 Feb; 37(2): 132 – 141.
22. Cook JL, Cook CR. Bilateral shoulder and elbow arthroscopy in dogs with forelimb lameness: diagnostic findings and treatement outcomes. Vet Surg. 2009 Feb; 38(2): 224 – 232.
23. Devitt CM, Neely MR, Vanvetchten BJ. Relationship of physical examination test of shoulder instability to arthroscopic findings in dogs. Vet Surg. 2007 Oct; 36(7): 661 – 668.
24. Hulse D, Young B, Beale B, Kowaleski M, Vannini R. Relationship of the biceps-brachialis complex to the medial coronoid process of the canine ulna. Vet Comp Orthop Traumatol. 2010; 23(3): 173 – 176.
25. Marcellin-Little DJ, Levine D, Canapp SO Jr. The canine shoulder: selected disorders and their management with physical therapy. Clin Tech Small Anim Pract. 2007 Nov; 22(4): 171 – 182.
26. Murphy SE, Ballegeer EA, Forres LI, Schaefer SL. Magnetic resonance imaging findings in dogs with confirmed shoulder pathology. Vet Surg. 2008 Oct; 37(7): 631 – 638.
27. Schaaf OR, Eaton-Wells R, Mitchell RA. Biceps brachii and brachialis tendon of insertion injuries in eleven racing greyhounds. Vet Surg. 2009 Oct; 38(7): 825 – 833.
28. Schaefer SL, Baumel CA, Gerbig Jr, Forrest LI. Direct magnetic resonance arthrography of the canine shoulder. Vet Radiol Ultrasound. 2010 Jul-Aug: 51(4): 391 – 396.
     

Introduction

Excision arthroplasty of the glenoid rim and humeral head provides a pseudoarthrosis based on fibrous tissue. It is an alternative to arthrodesis or amputation in conditions in which the shoulder joint cannot be adequately reconstructed. Indications for excision arthroplasty include chronic shoulder luxations in which the labrum of the glenoid cavity is excessively worn, severe degenerative joint disease, and irreparable intra-articular fractures, of which gunshot wounds are the most common example. The traditional method of treatment in these animals has been arthrodesis, which is technically demanding and requires bone-plating equipment in most cases.

While encouraging results have been obtained with this procedure, it has only been performed in a small number of patients. We recommend this procedure only as a salvage procedure with a fair to good prognosis for pain free normal, nonathletic function. As in the case of excision arthroplasty of the hip, more normal function can be anticipated in small breeds of dogs than in large breeds. The technique has been performed bilaterally in a small-breed dog with good functional results by 4 months postoperatively.

Surgical Technique

The shoulder joint is exposed by a craniolateral approach with osteotomy of the acromion process. The tendons of insertion of the infraspinatus and teres minor muscles are transected and retracted caudally with stay sutures. The joint capsule is cut close to the glenoid rim and opened widely, and the tendon of origin of the biceps brachii muscle is transected near the supraglenoid tubercle (Figure 55-40). Ostectomies of the glenoid rim and humeral head (Figure 55-41) are made with and sharp osteotome, oscillating saw, or high-speed rotating burr. Care is taken to protect the suprascapular nerve and caudal circumflex humeral artery during the ostectomies. If the suprascapular nerve passes too closely to the ostectomy site, a notch may be cut in the base of the scapular spine to allow proximal displacement of the nerve. An alternative to ostectomy of the glenoid rim is removal of the articular cartilage of the glenoid to expose subchondral bone, thus opening vascular channels. This also obviates the necessity to detach the biceps tendon.

If the tendon of the biceps brachii was detached, it is reattached to the fascia of the supraspinatus muscle. The teres minor muscle is pulled between the cut surfaces of the scapula and humerus and sutured to the biceps tendon and medial joint capsule (Figure 55-42). The remaining jont capsule is pulled into the ostectomy site and sutured to the teres minor muscle and tendon. This interposition of soft tissues between the cut surfaces of the scapula and humerus is thought to hasten the formation of a fibrous false joint (pseudoarthrosis). The infraspinatus muscle is sutured to its insertion on the humerus. Finally, the acromion process is reattached to the spine of the scapula. It may be necessary to wire the acromion process more proximally than normal to remove laxity in the deltoideus muscle. Subcutaneous tissues and skin are closed routinely.
 

Postoperative Care and Prognosis

Early use of the leg is encouraged by leash walking. Passive flexion and extension of the shoulder joint as well as analgesic therapy may be helpful in encouraging use of the leg. More vigorous activity is forced beginning 10 days postoperatively, and swimming is encouraged following suture removal. Early use of the leg stimulates the fibrosis necessary to create a functional pseudoarthrosis. Professional physical therapy starting at two weeks postoperatively will speed recovery.

Thirteen cases have been reported in two small series (Breucker and Piermattei 1988, and Franczuski and Parkes 1988). Good to excellent pain-free-function was obtained in each case. As previously noted, resection of the glenoid rim and humeral head must be considered a salvage procedure, and return to normal function of the limb cannot be expected. Pain-free use of the leg is usually achieved, although a mild gait abnormality and shoulder girdle muscle atrophy will be seen. Full recovery generally requires 3 to 6 months.

Suggested Readings

Breucker KA, Piermattei DL: Excision arthroplasty of the canine scapulohumeral joint: Report of three cases. Vet Comp Orthop Trauma 3:134, 1988.

Franczuski D, Parkes LJ: Glenoid excision as a treatment in chronic shoulder disabilities: Surgical technique and clinical results. J Am Anim Hosp Assoc 14:637, 1988.

Piermattei DL, Flo GL, DeCamp CE: Brinker, Piermattei, and Flo’s Handbook of Small Animal Orthopedics and Fracture Repair, 4th ed. Philadelphia. W. B. Saunders, 2006, p. 273.

Piermattei DL, Johnson KA: An Atlas of Surgical Approaches to the Bones and Joints of the Dog and Cat, 4th ed. Philadelphia. Saunders, 2004, p. 112.
 

Indications

Arthrodesis of the shoulder joint is not common but any condition resulting in intractable pain and dysfunction is an indication for arthrodesis. Malunion and highly comminuted articular fractures can lead to severe DJD. Untreated OCD and chronic luxation of the shoulder especially medial luxation in miniature breeds is another cause of DJD. It is unusual for the arthritis to be severely debilitating. But, when it is and conservative therapy is no longer controlling the pain arthrodesis becomes an option.

Surgical Approach

The approach to the shoulder is simplified by both an osteotomy of the acromial process of the scapula, and the greater tubercle of the humerus. The acromion process can then be retracted distally with the deltoid muscle. Osteotomy of the greater tubercle allows retraction of the supraspinatus muscle and also provides a smooth bed for the plate. The suprascapular nerve should be isolated and protected where it crosses the neck of the scapula. The biceps tendon can be transected from the supraglenoid tubercle if necessary (Figure 55-43).

Procedure

The cartilage is removed from both articular surfaces and a pin or K-wire is used to hold the joint in the proper position. This position is about 105 degrees and can be measured from the standing angle of the controlateral shoulder joint. Two flat congruent surfaces can be formed with an oscillating saw or osteotome. This will create a stable junction and also dictate the angle of the arthrodesis, an important consideration when making these cuts. Cancellous bone graft or substitute is placed between and around the fresh surfaces. Plates provide good long term, stable fixation and are the recommended implant. Compression should be used whenever possible. The scapula is a very thin bone and to get the best purchase for the screws the plate is placed along the cranial aspect of the spine and is twisted caudally to engage the bone where the spine arises from the body. Distally the plate is placed over the craniolateral aspect of the humerus. At least 4 to 5 screws should be placed in the humerus and in the scapula. The longer the plate the more the stresses are distributed and therefore not concentrated over the arthrodesis site. This is especially true of the scapular portion because of the thin bone and poor screw purchase. Care must be taken where the plate crosses the suprascapular nerve. The nerve can be placed under or over the plate depending on which places the least tension on the nerve itself. Part of the greater tubercle can be used for graft and the remainder can be attached to the humeral head. If the biceps tendon was transected it can be reattached to the humeral head with a screw and washer (Figure 55-44).
 

In small or miniature breed dogs combinations of compression screws and pins can also be used but with the availability of 1.5 mm and 2.0 mm plates I would still recommend plate fixation. After removing the cartilage, small pins or Kirschner wires can be passed from the glenoid or neck of the scapula into the humeral head and vise versa. A screw under compression can also be placed from the humeral head into the neck. The surfaces are prepared as described above. The problem with this fixation is that all the implants are concentrated right at the arthrodesis site where there are significant forces trying to create motion because of the long lever arm of the humerus. A secondary support such as a spica cast or splint extending over the shoulder and back will help distribute these forces and should be used with pin and screw fixation. The splint should be left on until signs of fusion are evident radiographically. Even with a plate fixation secondary coaptation is beneficial but does not need to be left on as long.

Even with a successful arthrodesis of the shoulder function may vary from patient to patient. However, there is still some motion preserved from the muscular sling that attaches the scapula to the body wall.
 

Suggested Readings

Piermattei DL, Flo GL: Brinker, Piermattei, and Flo’s Handbook of Small Animal Orthopedics and Fracture Repair 3rd Edition. W.B. Saunders. Philadelphia. 1997.

Lesser: Arthrodesis. In Slatter: Textbook of Small Animal Surgery. Saunders. Philadelphia. 2003.