Carpus, Metacarpus, and Phalanges

Introduction

The accessory carpal bone seems more prone to injury than the other carpal bones, perhaps because it is such an integral component of the palmar support structure that prevents hyperextension during full weight bearing. Fractures of this bone are commonly in the region of ligamentous insertions (sprain avulsion fractures), and frequently they involve the articular cartilage surface on the dorsal end of the bone that forms part of the accessory-ulnar carpal joint. Most fractures of this bone occur in racing greyhounds.^1,2 Similar types of fractures are seen occasionally in dogs of other breeds, and these fractures may be due to trauma, landing awkwardly on the limb, stepping in a hole while running, and falling from heights. Swelling, instability, and pain are common features of carpal injuries, but the diagnosis and classification of fractures are made from radiographs. Fractures can usually be visualized in mediolateral radiographic views with the carpus in full extension or slightly flexed. Additional information about the type and extent of the fracture can be obtained from the dorsopalmar radiographic view. Luxation of the accessory carpal bone, without any fracturing of the bone, can also result from severe trauma in sporting dogs.³

Fracture Classification

These fractures have been classified into five types, on the basis of their radiologic and pathologic features (Figure 58-1).^1,4,5
 

Type I

Injuries are avulsion of bone in the region of the insertion of the accessory-ulnar ligament. Fracture fragments may be large slabs or multiple comminuted chips that are best appreciated on the mediolateral radiographic views. These fractures involve the distal margin of the articular surface, and this feature, combined with disruption of the ligamentous support, leads to instability, subluxation, cartilage damage, and secondary osteoarthritis. Chronic fractures often do not proceed to bony union, and the bone fragments become surrounded by proliferative bone and fibrous tissue.

Type I fractures are further defined as being palmarolateral (type 1A) or palmaromedial (type 1B).^4,6 The type IA fracture of the palmaorolateral prominence may be visualized on a dorsolateral palmaromedial oblique radiographic view.

Type II

Injuries are avulsion fractures of the proximal margin of the articular surface and involve bone at the insertion of the palmar ulnocarpal and radial carpal ligaments that connect to the caudomedial surface of the distal ulna and the caudal surface of the distal radius. They are often associated with a type I injury. Like type I injuries, they allow subluxation, and articular cartilage damage and secondary osteoarthritis are sequelae.

Type III

Injuries are avulsion fractures of the distal surface of the palmar end of the bone, at the origin of the two large accessory-metacarpal ligaments that connect to metacarpal bones IV and V. Such injuries disrupt the stay apparatus provided by the accessory-metacarpal ligaments that normally counteract carpal hyperextension during full weight- bearing.

Type IV

Injuries are strain-avulsion fractures of bone from the proximal surface of the palmar end of the bone, at the tendon of insertion of the flexor carpi ulnaris muscle. Bone fragments are distracted proximally by the flexor tendon. The fracture may be an apophyseal avulsion in dogs up to 5 months of age.

Type V

Injuries include all other fractures of the carpal body, and these fractures may be comminuted or intra-articular. Fractures may be in a longitudinal, sagittal, or transverse plane, dividing the bone into two or more fragments.

Treatment and Prognosis of Fractures

Screw Fixation

Open reduction and internal fixation with screws are indicated in certain type I, II, and III injuries with large, noncomminuted bone fragments (Figure 58-2).^7,8 The aims of treatment are restoration of ligamentous integrity and the prevention of subluxation and secondary osteoarthritis. Dogs are positioned in lateral recumbency with the affected limb uppermost for surgery. A skin incision, 5cm long, is made palmarolateral to the carpus.⁹ The palmar carpal retinacular fascia is incised to expose the accessory carpal bone and supporting ligaments. The abductor digiti quinti muscle is elevated and is retracted medially from the accessory-metacarpal IV and V ligaments. A lateral arthrotomy of the accessory-ulnar joint is performed to allow inspection of the articular cartilage surface and accurate reduction in type I and II injuries. Small pointed AO/ ASIF forceps are used to maintain reduction (Figure 58-3). Lag screw fixation is with 1.5 or 2.0 mm cortical screws (Figure 58-4). If the fragment is thin, countersinking is not performed. The drill hole should be measured and tapped completely to minimize the risk of screw breakage, an occasional problem with 1.5 mm screws.
 

The internal fixation is protected with a palmar fiberglass slab splint for 4 to 6 weeks after surgery. Initially, the carpus is immobilized in slight flexion, but then it is moved progressively to a more extended position. Radiographs are taken at 6 and 12 weeks postoperatively to monitor fracture healing.

One study of 12 greyhounds with fractures treated by internal fixation found that 10 returned to racing, and five of those won one or more races.⁷ Animals with type I and II fractures are expected to have a worse prognosis because these fractures are intra-articular, but further studies are needed. Although internal fixation of these fractures seems more logical, this operation is technically demanding, and some fracture fragments are simply too small to permit screw fixation, so excision becomes unavoidable.

Fragment Excision

Removal of avulsed fracture fragments is an alternative treatment for type I and II fractures. Access for fragment excision is a limited lateral approach, similar to that used for lag screw fixation. Fragments are usually found attached to the accessory-ulnar ligament of the joint capsule, and they are excised with a No. 11 or 15 scalpel blade.

No attempt is made to suture the damaged ligament or capsule after fragment excision, and healing proceeds by fibroplasia. Without surgical treatment, type I and II fractures do not naturally heal by bony union, and often they damage the articular cartilage on the ulnar carpal bone. When internal fixation is not possible, fragment excision perhaps may be preferable to nonsurgical management, but further studies are needed. One study in Scotland found that, of 19 racing greyhounds that had type I fragments removed, 13 returned to race and nine won races. Of the other six, three became sound but were unable to race, whereas the other three remained lame.¹⁰

External Coaptation

For comminuted fractures that are not amenable to internal fixation and for minimally displaced fractures in young dogs, immobilization of the carpus in flexion is indicated. Malunion of the fracture may be well tolerated unless the fracture is intra-articular.

Partial Arthrodesis

Animals with hyperextension injuries confined to the accessoryulnar joint frequently have concurrent type I and II fractures of the accessory carpal bone. A partial carpal arthrodesis of this joint may stabilize the carpus while preserving motion in the antebrachiocarpal joint.¹¹ The surgical approach is similar to that used for fracture repair by internal fixation. After the joint is opened, articular cartilage is removed, the space is bone grafted, and a lag screw is placed in a palmarodorsal direction from the accessory carpal bone into the ulnar carpal bone. Additional support is provided by a cerclage wire from the palmar pole of the bone, down to the fifth metacarpal bone.

References

1. Johnson KA: Accessory carpal bone fractures in the racing greyhound: Classification and pathology. Vet Surgery 17:60, 1987.
2. Johnson KA, Dee JF, Piermattei DL: Screw fixation of accessory carpal bone fractures in racing greyhounds Twelve cases (1981 1986). J Am Vet Med Assoc 194:1618, 1989.
3. Guilliard MJ: Accessory carpal bone displacement in two dogs. J Small Anim Pract 42:603, 2001.
4. Johnson KA and Piras A (2005) Fractures on the carpus. In Johnson AL, Houlton JEF, Vannini R, eds.: AO Principles of Fracture Management in the Dog and Cat. Davos Platz: AO Publishing, 2005, p 341.
5. Chico AC: Characteristics of accessory carpal bone fractures: 25 cases. Proceedings 12th European Society of Veterinary Orthopaedics and Traumatology, Munich, 2004.
6. Boemo CM: Fracture of the accessory carpal lateral articular prominence in a racing ground. Aust Vet Pract 24:70, 1994.
7. Johnson KA, Piermattei DL, Davis PE, et al.: Characteristics of accessory carpal bone fractures in 50 racing greyhounds. Vet Comp Orthop Traumatol; 2:104, 1988.
8. Johnson KA: Carpal injuries. In Bloomberg MS, Dee JF, Taylor RA, editors. Canine Sports Medicine and Surgery. Philadelphia: WB Saunders 1998, p 100.
9. Piermattei DL and Johnson KA: An Atlas of Surgical Approaches to the Bones and Joints of the Dog and Cat. Fourth edition. Philadelphia: Saunders, 2004.
10. Chico AC: Accessory carpal bone fracture in greyhounds: assessment of prognostic indicators and outcome following surgical management by fragment removal. M Vet Med thesis, University of Glasgow, 1992.
11. Lenehan TM, Tarvin GB: Carpal accessorioulnar joint fusion in a dog. J Am Vet Med Assoc 194:1598, 1989.

Introduction

The carpus is a complex joint composed of seven bones arranged in a proximal row of three bones and a distal row of four bones. The radial carpal bone is the medial bone of the proximal row. It is the largest of the carpal bones and articulates with the radius. The lateral bone of the proximal row is the ulnar carpal bone and articulates with the ulna and with the radius. The accessory carpal bone is located on the palmaro lateral aspect of the proximal row and articulates with the ulnar carpal bone and with the ulna styloid process. The four carpal bones of the distal row are named from medial to lateral as I, II, III, and IV.

Three joint levels are present: the antebrachiocarpal joint between the distal end of the radius and ulna and the proximal row of carpal bones, contributing 70% of the carpal motion; the middle carpal joint is between the proximal and distal row of carpal bones and contributes 25% of total carpal motion; and the carpo-metacarpal joint between the distal row of carpal bones and the bases of the metacarpal bones that contributes only 5%.

The carpal joint is a complex ginglymus joint that allows movements of extension, flexion, internal and external rotation, a few degrees of valgus, varus and a few millimeters of translation in the palmaro dorsal direction. Several ligaments join the various bones at different levels. The dorsal ligaments are quite thin and join the adjacent bones individually, the palmar ligaments are thicker and are in part embedded in the robust palmar fibrocartilage that attaches to the palmar aspect of the carpal bones and to the bases of the metacarpal bones (with the exception of the accessory carpal bone). This structure provides a strong support to the palmar aspect of the carpal joint and is constantly under tension. The collateral ligaments are strong, especially the medial ligament that is constantly under tension due to a normal five degrees of carpal valgus that is present. Unlike the tarsus, the collateral ligaments span only one joint level. The joint capsule separates the antebrachiocarpal joint from the middle carpal and carpo-metacarpal joints, creating two separated compartments. The types of carpal injuries include sprain, hyperextension, luxation and fracture.

Clinical Examination

Carpal fractures are usually avulsion fractures of ligaments (origin or insertion) and tendon insertions or the result of the combination of shearing and compressive forces acting on the bones during hyperextension. Most of these fractures are intra articular with few exceptions.

The clinical examination consists of palpation to localize pain, soft tissue swelling, crepitus and joint instability. The range of motion of the joint should be tested in flexion and extension. Additional maneuvers include internal or external rotation of the carpal joint while in extension or 90 degrees of flexion. Cranial translation is evaluated with the carpus in 90 degrees of flexion. Both are useful tests for an accurate evaluation of joint stability. In cases in which carpal damage is suspected, but the injury cannot be localized, it is useful to apply a well padded compressive bandage, supported by a palmar meta-splint, prescribe an anti-inflammatory and rest. After two or three days, re-examine the patient, the decrease in soft tissue swelling will facilitate the examination.

Radiographic Examination

Radiographic examination of the carpus starts with routine views. However, due to its anatomical complexity, injuries may be obscured by the superimposition of the different bony structures. In order to make or confirm the diagnosis of a suspected injury, supplemental or additional radiographic views are often required.

Additional radiographic views often consist of special projections such as flexed or extended oblique views and stress views.

Stress projections, are views taken during “the application of controlled force to a joint to demonstrate abnormal spatial relationship between two or more of its components”(Farrow 1982). Stress views can be obtained by application of shear, traction, wedge and rotatory maneuvers. When ligamentous injuries are suspected, stress views are invaluable in demonstrating the presence of subluxation, joint instability, or in evaluating the location and size of avulsed fragments.

A variation of stress views are; the weight bearing views, taken with the dog in standing position and the x-ray beam in horizontal position in respect to the weight bearing limb. Adequately exposed radiographs are essential and high detail screens, such as rare earths and mammography mono-emulsion films are recommended to achieve fine detail. Whenever doubts about the radiographic anatomy exist it is helpful to x-ray the contra-lateral normal limb for comparison. In cases of hairline or incomplete fractures is useful to repeat the x-ray in a week so that osteolysis can highlight the fracture line.

Routine Projections

Medio-Lateral (ML) views and Dorso-Palmar (DP) views

Additional Projections

Dorso-Lateral Palmaro-Medial Oblique 45 degrees (DLPMO);
Dorso-Medial Palmaro-Lateral Oblique 45 degrees (DMPLO);
Medio-Lateral Flex (ML-Flex): this view is helpful to evaluate the dorsal articular margin of the radius, the dorsal surface of the radial carpal bone and the articular surface of the accessory carpal bone.

Stress Views

Hyperextended ML views are very useful to evaluate palmar instability, subluxation of the radial carpal bone, subluxation of the proximal carpal joint, subluxation and luxation of the carpometacarpal joints and fractures affecting the accessory carpal bone.

DP views with application of lateral or medial stress: very helpful views in case of suspected collateral instability, damage to the collateral ligaments with avulsed fragments from the styloid process, subluxation of the second carpal bone, carpo metacarpal collateral instability.

Dedicated Views

Specific radiographic views are sometimes necessary to critically evaluate some of the carpal bones or the dorsal articular margin of the radius and the ulnar styloid.
Palmaro-Lateral Dorso-Medial hyper flexed oblique view (PLDM-Flex)
Palmaro-Medial Dorso-Lateral hyper flexed oblique view (PMD-Flex). (Figure 58-5A, B, and Figure 58-6).

Skyline or tangential views are invaluable for a complete evaluation of the dorsal aspect of the radius. This view, with other views, can confirm the presence of a fracture or chip affecting this region. Incomplete fractures and small chips can sometimes be detected only with the aid of this view (Figure 58-7, and Figure 58-8A and B).
 

Treatment Principles

Complex fractures of the carpal bones are associated with ligament damage, severe comminution, and variable degrees of subluxation. Therefore, careful preoperative planning should consider the type of fracture in relation to the age, breed and the expected level of physical activity of the dog, the level of expertise of the surgeon and the availability of mini implants; after reviewing these considerations, arthrodesis may be the best choice. Open reduction and internal fixation is the treatment of choice to achieve results compatible with normal joint function. Carpal fractures are usually treated with K wires and tension-band wiring, or lag screw fixation. In case of non surgical treatment, as for any other intra-articular fracture, the development of osteoarthritis due to fracture instability is expected.

Fractures of the Radial Carpal Bone (RCB)

Fractures of the body of the RCB are uncommon injuries and are usually caused by compressive forces during hyperextension of the carpal joint. Different types of fractures have been identified: midbody saggital, saggital oblique (this fracture can be either complete with displacement or a hair-line fracture), comminuted or “Y” shaped composed generally of three fragments; and fracture of the dorsal margin (usually a small chip) (Figure 58-9).
 

Midbody fractures are often incomplete and have been described in racing Greyhounds. Some authors suggest that these fractures are more common in the right leg (Dee, personal communication: 6 cases) but insufficient numbers exist to completely define this type of predisposition. Overall, the clinical signs are variable. With complete fractures, the dog is lame and often non-weight bearing on the limb. Joint swelling, pain upon palpation, crepitation, and decreased range of motion in flexion is usually present. With hairline fractures, the diagnosis can be very difficult as this type of injury is subtle, showing minimal clinical signs, minimal joint effusion, and pain only on forced flexion. Radiographic examination consists of DorsoPalmar (DP) and Medio-Lateral (ML) views. In addition to the routine views, PMDL-Flex, PLDM-Flex, Dorso-Palmar oblique, and Skyline views are recommended.

With incomplete fractures, the fracture line may not be detectable for several weeks, until bone resorption creates some widening at the fracture line. These fractures are intra-articular and are treated with open reduction and internal fixation. According to the type, the fracture can be approached surgically either with a standard dorsal or a palmaro-medial approach or a combination of the two.

Midbody fractures are accurately reduced and stabilized with lag screws, generally 1.5, 2.0 or 2.7 mm cortical, inserted from the palmaro-medial aspect of the bone in an oblique dorso-lateral direction. Accurate countersinking of the screw head and precise measurement of the screw length are vital to avoid interference of the implant with adjacent bones or soft tissues (Figure 58-10).
 

Some authors suggest that “Y” shaped fractures of the RCB that occur without a history of trauma share a common etiopathogenesis. Considering that the two main fracture lines recognized on radiographs and CT scan correspond approximately to the fusion planes of the three ossification centers of the bone, it has been hypothesized that an incomplete fusion of these areas predisposes to this injury. According to these authors, the breeds most commonly represented are the Boxer, Labrador Retriever, English Setter, English Springer Spaniel and Pointer. These breeds often present with bilateral involvement. In acute cases, an attempt at fixation can be made using two 1.5 or 2.0 mm lag screws inserted from the dorsal fragment to engage the medial and the lateral fragments (Figure 58-11). Due to the nature of these fractures they tend to respond poorly to internal fixation. The fragments are prone to non-union with resulting implant failure and subsequent osteoarthritis. In most of the cases, these fractures are best managed with pan-carpal arthrodesis.
 

Fracture of the palmar process has been described as a sprain avulsion of the palmar radial carpo-metacarpal ligament. This injury is treated with open reduction and internal fixation using lag screws or K-wire and tension band wire techniques (Figure 58-12).
 

Dorsal RCB chip fractures are extremely common in racing Greyhounds consisting in most cases of a small chip. They are likely the result of impingement of the distal dorsal margin of the radius over the RCB during hyperextension of the joint. The history is variable with the trainer reporting poor performance and the dog “checking” and running wide in the turns. Lameness, when present, usually appears following intense exercise and tends to disappear within 12 hours. Clinical examination usually reveals pain with flexion. Joint effusion can be minimal to absent. Direct finger pressure on the dorsal aspect of the carpus does not necessarily elicit a pain response. Diagnostic radiographic views are usually the medio-lateral and medio-lateral oblique. In many cases, skyline views are of invaluable help to define three dimensionally the fragment location, thus decreasing the size of the surgical approach and the surgical time. With small chip fractures surgical removal is the treatment of choice. Larger slabs can be reduced and stabilized with 1.0 or 1.5 mm screws applied in a lag fashion, while insuring that the screw head is well countersunk.

Fractures Of The Other Carpal Bones

Ulnar Carpal Bone

Complete fractures are very rare, however they have been observed in conjunction with other carpal fractures and luxations, as well as an isolated fracture. Fractures affecting the palmar component are quite difficult to diagnose with routine radiographic views. In addition to routine views the PMDL- Flex view offers an excellent visualization of the palmar aspect of the bone (Figure 58-13). Treatment consists of stabilization of the fragment with a lag screw inserted in palmaro dorsal direction.
 

Dorsal chip fractures are more common and are often detected as an incidental finding. They share the same etiopathogenesis, diagnostic approach and treatment as the RCB dorsal chip.

Second and Third Carpal Bones

These uncommon and isolated fractures usually consist of a very small chip or a dorsal slab. In addition to routine radiographic views, ML-Flex, Semi Flex views and either standard and/or oblique are recommended.

Treatment consists of surgical excision of the small chips and lag screw fixation for larger dorsal slabs.

Post Operative Considerations

Following surgical repair of the fracture, the carpus is supported with a padded bandage and a palmar splint from 2 to 4 weeks according to the severity of the injury. Restricted and controlled activities are maintained until radiographic signs of healing are evident. Avoid prolonged immobilization of the carpus and promote early physiotherapy. In case of chip removal apply a light padded bandage to decrease postoperative swelling. The bandage is usually removed after a week and physiotherapy is started after 2 weeks.

Fractures of the Distal Radius and Ulna

Fractures of the Radial Styloid

These are uncommon intra-articular fractures. They are avulsion sprain fractures of the origin of the short radial collateral ligament. Normally the short radial collateral ligament provides medial stability for the antebrachiocarpal joint in both flexion and extension. This ligament has two components originating on a tubercle on the styloid process and inserting respectively on the medial (straight portion) and palmaro-medial (oblique portion) aspects of the radial carpal bone.

Clinical signs include variable degrees of lameness according to the severity of the injury, soft tissue swelling (usually diffuse around the carpal region), and pain upon palpation and manipulation of the area.

Treatment Principles

These fractures are treated by open reduction, accurate anatomical realignment and internal fixation. The surgical exposure is made with a longitudinal incision directly over the styloid process. In case of a larger fragment, a dorsal approach to the carpal joint can be combined to evaluate the quality of fracture reduction.

Several fixation techniques have been described, including K wires with a figure-of- eight tension band wire for the small fragments, or multiple divergent K wires or lag screws and anti rotational K wires for larger fragments. Very small fragments can be excised (Figure 58-14A, B, Figure 58-15 and Figure 58-16).
 

When inserting K wires, it is always advisable, in order to achieve better stability, to drive them from the fragment across the metaphyseal bone into the far cortex.

Fractures of the Ulnar Styloid

The ulnar styloid process, in association with the radial styloid, buttresses the proximal carpal bones. The short ulnar collateral ligament, the radio-ulnar ligament, and the palmar ulno-carpal ligament, originate on the ulnar styloid, providing lateral and palmar stability for the joint. Fractures of the ulnar styloid can be divided into two types: fractures affecting the proximal portion of the styloid, (usually 1 to 3 cm from its distal end) and fractures of the distal portion characterized by a small avulsed fragment.

Ulnar styloid fractures are not necessarily intra-articular and if incomplete, can be treated conservatively with external coaptation. Complete fractures can be associated with antebrachiocarpal subluxation, luxation of the radial carpal bone, or accompanied by fracture of the radial styloid; in any case they require open reduction and internal fixation.

Technique of choice is generally K wires with a figure-of-eight tension band wire for distal fractures and IM pinning or a small lateral plate (2.0/2.7 mm VCP or DCP) for more proximal fractures (See Figures 58-15 and 58-16).

Post Operative Considerations

A post operative bandage is recommended to support the repair of styloid fractures, with restricted and controlled activity maintained until radiographic signs of healing are evident. Implants are left in situ unless they become loose or are irritating the soft tissues.

Fractures of the Dorsal Articular Margin of the Distal Radius

Fractures of the distal articular radius can involve the central or lateral portions of the articular surface. As with any other intra articular fracture, open reduction and rigid, “gap free” internal fixation is preferred. This fracture of the dorsal articular margin of the radius was first described in racing Greyhounds by Ferguson (1986). Although not common in the pet population, it has been described in sporting breeds. The following information on this injury is focused on the racing Greyhound. This fracture is most commonly located at the origin of the dorsal radiocarpal ligament that joins the dorsal articular margin of the radius with the ulna carpal, is probably caused by a combination of compressive and torsional forces during hyperextension of the carpal joint. The history can be subtle; usually the trainer reports the dog “checking” in the turns and running wide. The lameness affects the dog for the first 24/36 hours after a trial or race but the dog is weight bearing. Generally, after a few days the dog seems to be normal but is lame again after a gallop or a trial. The clinical examination reveals pain in flexion, as well as on internal or external rotation of the carpus. Cranial translation with the joint at 90 degrees of flexion elicits a pain response. Swelling is not a constant finding and identifying the lesion by the application of direct pressure does not necessarily evoke a pain response. Radiographic examination consists of multiple views including standard and oblique views. Some authors describe the straight medio-lateral as the best diagnostic view. The radiographic findings of 150 cases have been compared to determine the location and type of injury and the sensitivity of standard lateral, dorso palmar and oblique views compared with skyline (tangential) views. The results of this unpublished study suggest that there are four types of lesions that can be described and that the skyline view is, in some cases, the only diagnostic view allowing identification and location of the injury. When available, CT scan is the tool of choice due to its superior diagnostic sensitivity. On the basis of the radiographic and surgical findings, four main lesion patterns are recognized. The first type consists of chondromalacia and erosion in the area of the origin of the dorsal radio-carpal ligament. The second type is an incomplete mono-cortical fracture, usually perpendicular to the dorsal articular margin, entering the joint for a few millimeters. The third type is a fracture avulsion of the origin of the radio-carpal ligament consisting of one fragment, or multiple small fragments, ranging from 2 to 6 mm in size. The fourth type is a dorsal slab fracture, which is usually complete and non-displaced, varying in size from 1 cm to a large slab (Figure 58-17A, B, C, and D). The fracture is exposed with a small incision made, between the extensor carpi radialis and the common digital extensor tendon. Surgical removal of small fragments by curettage and/or lag screw fixation of larger or incomplete fractures, offers the best prognosis (Figure 58-18 and Figure 58-19). Removing the small fragments creates damage to the dorsal radio-carpal ligament that heals by formation of fibrous tissue. The involvement of this small ligament in the etiopathogenesis of this type of fracture and its role in the joint’s stability is yet to be clarified.
 

Post Operative Considerations

After the surgery a light bandage is applied on the carpus for 10 days. After suture removal, a light bandage is reapplied for another 15 days and light exercise and physiotherapy are encouraged. The dog is expected to restart training between 6 and 10 weeks after surgery

Suggested Readings

Johnson KA: Carpal Injuries. In: Canine Sports Medicine and Surgery. Bloomberg MS, Dee JF, and Taylor RA eds. W.B. Saunders Company, 1998, 100-119.

Johnson KA, Piras A: Fractures of the Carpus. In: AO Principles of Fracture Management in the Dog and Cat. Johnson AL, Houlton JEF, and Vannini R eds. AO Publishing 2005, 341-348.

Li A, Bennett D, Gibbs C, Carmichael S, et al: Radial carpal bone fractures in 15 dogs. JSAP 41(2):74, 2000.

Tomlin JL, Pead MJ, Langley-Hobbs SJ, et al: Radial carpal bone fracture in dogs. JAAHA 37(2):173, 2001.

Boemo CM: Chip fractures of the dorsal carpus in the racing greyhound: 38 cases. Aus Vet Practit 23:139, 1993.
 

The purpose of partial carpal arthrodesis is to provide a bony union across the carpometacarpal, middle carpal, and intercarpal joints. Indications for this procedure include luxation, subluxation (e.g., hyperextension injury), chronic instability resulting in degenerative joint disease, intra-articular nonunion, and arthritis (septic or immune-mediated) not responsive to medical treatment. The antebrachiocarpal joint must be stable and pain free. Stability is assessed by palpation and stress radiography. Instability and subluxation of the accessory-ulnar carpal joint complicate partial carpal arthrodesis, making pancarpal arthrodesis the procedure of choice.

The animal is placed in dorsal recumbency. The limb is prepared for surgery. Proper use of a temporary tourniquet fashioned of wide Penrose drain or elastic bandage material facilitates the surgical procedure. Access to the joints involved is gained through a cranial approach. The skin incision is offset, to avoid overlying bone plates directly. The middle carpal, intercarpal, and carpometacarpal joints are opened with full carpal flexion, and the cartilage surfaces removed using an air-powered bur and rongeurs. The joints are then Iavaged thoroughly and are placed in extension (neutral alignment of carpal and metacarpal bones) and stabilized. Preferred stabilization uses a cranially applied T or L plate with screws in the radial carpal, intercarpal (if possible), and metacarpal bones. A single plate overlies the proximal third or fourth metacarpal bone (Figure 58-20). Larger dogs may have two opposite-angle L plates applied, allowing screw purchase in the radial and ulnar carpal bones and both central metacarpal bones (Figure 58-21). Proper plate and screw placement is crucial to avoid impingement of screws or plates on the antebrachiocarpal joint. Cancellous bone graft harvested from the ipsilateral humerus is liberally packed into all joints to be fused, and overlying tissues are closed in a routine manner. An alternative method of fixation uses intramedullary Kirschner wires placed in retrograde fashion from the distal dorsal surfaces of the second, third, fourth, and fifth metacarpal bones, seating into the radial and ulnar carpal bones (Figure 58-22).
 

Postoperative radiographs (including stress views) determine implant placement and the need for further implant removal if antebrachiocarpal joint impingement is noted. Postoperative management includes 6 weeks in a cast or splint and implant removal at the time of bony fusion if clinically indicated.

Proper patient selection and procedure are paramount for success. Insufficient evaluation of a pathologic antebrachiocarpal joint may allow progressive hyperextension and may require subsequent pancar-pal arthrodesis. Careful radiographic comparison of the accessory-ulnar carpal bone articulation with normal stress radiographs is helpful. Proper placement of implants can be facilitated by careful antebrachiocarpal joint arthrotomy to visualize radial and ulnar carpal bone geometry. Persistent lameness may require re-evaluation of implant placement or of antebrachiocarpal joint disease.
 

Indications

The primary indication for pancarpal arthrodesis is irreparable damage to the articular surfaces of the antebrachiocarpal joint or the soft tissues around the joint that causes intractable pain and loss of limb function. This damage may be from trauma, infection or arthritis. Examples of trauma would be highly comminuted fractures of the articular surface or fracture luxations with significant soft tissue and or bone loss where a primary repair would still be unstable. Severe cartilage damage can also result from chronic osteoarthritis, infection from septic arthritis or open, infected fracture luxations. Rheumatoid arthritis, seen mostly in small breeds, causes severe ligamentous instability that does not respond well to soft tissue repairs. Pancarpal arthrodesis is effective in these cases but the disease may affect multiple joints. Partial carpal arthrodesis is sufficient in those cases with hyperextension injuries where the antebrachiocarpal joint is not damaged.

There are other less common indications for pancarpal arthrodesis. It is used to increase purchase for a plate in the fore leg with atrophic nonunions of the radius and ulna in miniature breeds, and limb salvage procedures for Osteosarcoma treatment. In both of these cases there is not enough distal radius to anchor a plate. Arthrodesis allows the plate or External Skeletal Fixator to extend down to the metacarpal bones. Radial paralysis and mild brachial plexus injuries can be treated with a pancarpal arthrodesis. Pure radial paralysis is rare. There are other treatments such as muscle transfers, but pancarpal arthrodesis to keep the paw in the proper orientation is one alternative. These animals may still bear weight on the side of the paw and a protective boot may be necessary. In Brachial plexus injuries the patient must be able to extend the elbow in order to make the procedure worthwhile. Fusing the carpus in severe brachial plexus injuries with a nonfunctional elbow will not have any benefit.

Procedure

In a pancarpal arthrodesis, the antebrachiocarpal, middle carpal, and carpometacarpal joints are included. It has been reported that fusing only the antebrachiocarpal joint and not the distal joints will lead to degenerative joint disease of the latter due to excessive stress. All the cartilage in these joints must be removed with a power burr or curette. The fascia, joint capsule and intercarpal ligaments must be incised to expose the cartilage. With a dorsal approach the cephalic and accessory cephalic veins and the common digital extensor tendons must be retracted but the extensor carpi radialis and abductor pollicus longus tendons can be sacrificed to expose the intercarpal and carpometacarpal joints. Some form of graft material should be placed between the denuded joint surfaces. Autogenous cancellous chips are the best but there are now numerous choices from freeze dried, decalcified, cancellous allograft to artificial Ca Phosphate substitutes. The carpus is fixed in 5 to15 degrees of dorsiflexion to place the foot in a more natural weight bearing position.

Plate fixation is the most commonly used method although external fixators and even cross pins have been advocated. Both plates and external skeletal fixation are acceptable methods of providing stable long term fixation. External fixators have an advantage in type III open fractures or at the site of an infection. No metal is buried and it is possible to treat the open wounds around the fixation. A type II, or rarely, a type III ESF can be used. Ring fixators and hybrids are also an effective choice in these situations. In clean, uncomplicated cases plates are usually the preferred implant and are better tolerated during the long periods required for arthrodesis. DCP plates also have the advantage of applying compression across multiple joint surfaces. The plate is placed dorsally (Figure 58-24) in most cases. The plate can also be placed ventrally, which is the tension band side, although this approach is much more difficult and involved (Figure 58-25). There is also a recent report in which the plate is placed on the medial aspect of the radius and carpus. This placement removes the plate from the compression side of the fixation. The newer locking plates can be contoured in four directions allowing the 10 to 15 degtrees of dorsiflexion with a medial plate. By far the most commonly used position is dorsal. Three or four screws are placed in the radius, one in the radiocarpal bone to pull it up to the plate, and at least 3 in the 3rd or 4th metacarpal bone. Depending upon how the plate lays on the radius and intrercarpals it may line up on either the 3rd or 4th metacarpal. Some newer plates taper down distally permitting the use of smaller screws for the metacarpal bones For example a 3.5 mm screw and plate over the radius and radiocarpal bone and 2.7 mm screws for the metacarpal bone. Others allow placement of screws in both the 3rd and 4th metacarpals.
 

A cast is usually added to plate fixation since there is no worry about joint stiffness and it adds a measure of safety. The cast can be left on until radiographic signs of fusion are seen, or removed at the discretion of the surgeon in a smaller quieter patient. The plates are rarely removed but fractures at the end of the plate are a concern in large active patients.

Suggested Readings

Chambers JN, Bjorling DE: Palmar surface plating for arthrodesis of the canine carpus. J Am Anim Hosp Assoc 18:1875. 1982.

Ehrhart, N: Longitudinal Bone Transport for Treatment of Primary Bone Tumors in Dogs: Technique Description and Outcome in 9 Dogs. Vet Surg. 34: 24-34, 2005.

Gambardella PC, Griffiths RC: Treatment of hyperextension injuries of the canine carpus. Comp Cont Educ 4:127.1982.

Johnson KA: Carpal arthrodesis in dogs. Aust Vet J 1 56:515.1980.

Johnson KA, Bellenger CB: The effects of autologous bone grafting on bone healing after carpal arthrodesis in the dog. Vet Rec 107:126. 1980.
 

Introduction

Metacarpal and metatarsal fractures are a common injury in small animals. Although they can occur from direct trauma or from a collision against a stationary object, other causes are recognized. Entrapment of the paw while leverage is applied to the area or a fall can cause the fractures. Fractures caused by falls usually have associated hyperextension injuries.

In a retrospective study of 37 cases of meta-bone fractures, metatarsal fractures were over represented (Muir 1997). Fractures of one metacarpal or metatarsal bone occurred in 24% of the dogs, two meta-bones were involved in 16% of the cases, three meta-bones in 19% and four meta-bones in 41% of the cases. Fractures of the metacarpal/tarsal bones are classified according to their anatomical location: fractures of the proximal end (base), fractures of the shaft, and fractures of the distal end (head).

Clinical Examination

The degree of lameness that is observed increases as the severity of the injury increases. Isolated non-displaced fractures affecting the II or the V meta-bones, can cause a mild lameness that tends to resolve in 48 to 72 hours. Fractures affecting the III and IV bones or multiple bones are generally accompanied by severe non-weight bearing lameness. Clinical signs in acute cases include: swelling, and pain on digital palpation. With complete fractures, crepitus and deformity are usually also detectable.

Radiographic Examination

A complete radiographic assessment should include dorsopalmar/plantar and lateral views. Isolated metacarpal\tarsal views are not possible. Dorso-palmar/plantar 15° oblique views and lateral 45° oblique views (Figures 58-26, 58-27 and 58-28). are often necessary to isolate individual bones or to evaluate complex multiple fractures.
 

Preoperative Considerations

The application of a modified Robert Jones bandage supported by a meta-splint for 24 to 48 hours prior to surgery will dramatically decrease swelling and facilitate fracture reduction. Application of a stockinette will enhance skin retraction and sterility. Judicious use of a tourniquet will decrease bleeding.

Surgical Approachs

(Figure 58-29A, B and C)
 

Fractures of the Base

Basilar fractures usually involve the second and the fifth metabones. These uncommon fractures are usually avulsions of ligament or tendon insertions and may be associated with some degree of varus/valgus deviation of the foot. Conservative treatment is considered for non-displaced, stable fractures. In the case of unstable fractures the fragment tends to displace due to the pulling action of the ligament or tendon; the risk of mal-union and consequent angular deviation justifies open reduction and internal fixation as the treatment of choice in these cases.

Fixation can be achieved with a small K wire and a figure-of-eight tension band wire or with multiple 1.5 mm or 2.0 mm lag screws (Figure 58-30). The most proximal screws are usually inserted to engage the proximal cortex of the adjacent meta-bone. Comminuted fractures of the base can be repaired with a small plate (Figure 58-31). A careful clinical and radiographic examination with stressed views is necessary to assess complex and multiple basilar fractures, as they can be associated with a hyperextension injury, resulting in palmar/plantar and lateral or medial instability. These complex injuries are best treated with carpal arthrodesis.
 

Fractures of the Shaft

Metacarpal/tarsal fractures can be treated either conservatively or surgically: Displacement of shaft fractures is limited by the surrounding soft tissue structures and by the support of the adjacent meta-bones. Transverse fractures of one or two metacarpal/tarsal bones, if located in the proximal and middle third tend to be stable, and can be treated with closed reduction and external coaptation. The meta-bones tend to spread in their distal third and less adjacent support is present, so fractures located in the distal portion of the shaft tend to displace, and are more difficult to maintain in a reduced position with conservative treatment.

Internal fixation of shaft fractures is usually indicated when there are more than two metacarpal/tarsal fractures in the same leg, when the two weight-bearing bones (third and fourth) are fractured, or when there is significant displacement or shortening. In large breed dogs and athletic or working dogs, fractures of even a single bone are ideally treated with internal fixation in order to achieve the best functional results.

Transverse Fractures

Transverse fractures often result from a direct blow. These fractures usually present with dorsal angulation and palmar/ plantar displacement of the distal fragment, due to the direction of the deforming forces and the pull of the interosseous muscles and flexor tendons.

Plate application of transverse fractures assures a very stable fixation. External post-operative support needs to be maintained for a shorter period compared with other methods of internal fixation, thus speeding the functional recovery and allowing an earlier rehabilitation. The plate is applied to the dorsal aspect of metacarpal/tarsal III and IV, to the medial aspect of metacarpal/ tarsal II and to lateral aspect of metacarpal/tarsal V (Figure 58-32). The Veterinary Cuttable Plate (VCP-Synthes™) is an excellent implant for repair of large patient metacarpal/tarsal fractures. These plates, available with 1.5 mm/2.0mm and 2.0 mm/2.7 mm screw holes, offer unique advantages; a thin profile plate with close screw holes and excellent mechanical properties.

Intramedullary pinning has been described as a successful method of treatment. A small size Kirschner wire (1.5 or 2.0 mm) can be inserted orthograde (normograde), starting distally, close to the dorsal attachment of the joint capsule. Reduction is achieved with a combination of traction and leverage applied with a small periosteal elevator. The pin is driven into the proximal fragment to the base of the bone. The protruding portion of the pin is cut after bending it into a hook shape. Ideally, the pin should be retracted slightly, bent into a hook and then reseated into the base in order to diminish the irritation of the pin to adjacent joint structures. A slot can be created with a high-speed burr to facilitate the insertion of the pin and the lodgement of its tip (Figure 58-33). Pre-sizing the length of the pins to the pre-operative x-ray will reduce the risk of penetration of the base and violation of the carpo-metacarpal/ tarso-metatarsal joints. Intramedullary pinning is advocated for fractures that are stable after reduction, for fractures in young non-athletic breeds and for fractures involving only one or two meta-bones.
 

Oblique Fractures

Oblique and spiral fractures tend to telescope--producing shortening and rotational deformity. Because these factors are difficult to control by external coaptation, the best option is open reduction and internal fixation. Most long-oblique and spiral fractures can be successfully repaired with multiple lag screws. Screws can be used as the only form of fixation if the length of the fracture is at least twice the diameter of the metacarpal/ tarsal bone and a minimum of two screws can be placed (Figure 58-34). Countersinking of the screws will improve the loading characteristics and will decrease soft tissue irritation. Whenever required, the repair can be supported with a neutralization plate. This is especially valid for fractures involving the III or IV meta-bones. Multiple cerclage wiring has been described as a successful alternative to screw application; however the author does not recommend this technique. Cerclage wiring in conjunction with lag screws may be useful in selected cases.
 

Comminuted Fractures

Reconstructable comminuted fractures are best repaired with a combination of lag screws and mini plates or VCP. Large fragments can be lagged through the plate.

For highly comminuted fractures, a biological approach is recommended. Due to the anatomical characteristics of the area, the intact meta-bones offer a natural splintage to the fractured bone, minimizing the necessity for a perfect anatomical reconstruction. The plate can simply bridge the fracture, guaranteeing axial alignment and length.

Comminuted open metabone fractures have been successfully treated using external fixation, either with linear fixators, using epoxy resin putty, or with ring fixators.

Fractures of the metaphysis, immediately proximal to the condyles, are uncommon. These fractures are usually transverse, and tend to be stable, with the proximal fragment impacted a few millimeters into the distal fragment. A mild rotational deformity may be present. Conservative treatment with external coaptation is sufficient for isolated injuries. Surgical treatment is indicated when the fracture is in combination with other metacarpal\tarsal fractures or when it is displaced and difficult to reduce. Two pins inserted in a Rush fashion medial and lateral to the condyles and driven proximally are generally sufficient for repair (See Figure 58-33). In sporting dogs, the use of a more stable fixation with mini T or L finger-plates is recommended (Figure 58-35).

Fractures of the Head

Fractures of the head are usually intra articular fractures involving the condyles and consequently the metacarpo/tarso– phalangeal joint. Closed reduction is only used for incomplete or non-displaced fractures. Surgical treatment is indicated for mono-condylar and for T or Y fractures. Internal fixation is achieved with a lag screw or with a small cerclage wire for simple fractures and with mini T or L plate for more complex fractures (See Figure 58-35).
 

Post Operative Treatment

After surgery, a padded bandage is applied for approximately 3 to 4 weeks or until radiographic signs of bone healing are seen. Kennel confinement is strongly recommended until bandage removal. This period is followed by 4 to 8 weeks of restricted exercise. Fractures involving multiple bones will require either a cast or a molded splint.

Conservative Treatment

A padded bandage is reinforced with a molded splint or with a fiberglass cast. Kennel confinement and rest are required until there are radiographic signs of bone healing, which occurs usually within 4 to 8 weeks.

A retrospective study comparing the outcome of metacarpal/ tarsal fractures treated conservatively versus surgically suggests that the outcome was not statistically affected by surgery or conservative treatment however this was a small non-randomized population of pet dogs, not performance nor working dogs (A. Kapatkin 2000).

Metacarpal/Tarsal Fractures in Racing Greyhounds

Metacarpal/tarsal injuries are extremely common in the racing greyhound with a high incidence in dogs between 14 and 28 months of age. Metacarpal and metatarsal fractures are, for the vast majority, fatigue or stress fractures resulting from repetitive cyclical loading as documented by (Bellenger C.R.et al 1981, Boemo 1989 & Johnson A. K. 2001). Exceptions are the traumatic fractures sustained in a fall, or following a collision against stationary objects.

Traumatic injury can involve any metacarpal bone but are usually multiple, involving two to four bones. Stress fractures almost always involve the left V and the right II metacarpal bones. Fracture of the IV left metacarpal bone can be associated with a fracture of the V left metacarpal bone, and has not been described or reported as an isolated injury. The metatarsal bones affected by stress fractures are the left V and the right III. Greyhounds are high performance dogs and internal fixation is recommended in the majority of the cases.

Phalangeal Fractures
Introduction

Phalangeal fractures are common injuries and are often considered insignificant. As a direct consequence of this underestimation, the treatment of these injuries is not always optimal. The most common complications associated with inappropriate treatment of phalangeal fractures are: malunion with imbalance of the flexor and extensor mechanism, limited range of motion, degenerative joint disease and deformity with interference between toes.

There are a variety of factors to consider when deciding the optimal treatment. Breed, age, type of activity, owner expectations and compliance, as well as injury characteristics, pattern of the fracture, and soft tissue damage are all important when establishing a treatment plan.

The goal of the treatment of fractured phalanges is to achieve the best possible reduction and the most effective means of maintaining the reduction in order to promote bony union, early mobilization and function. This concept is particularly valid for sporting dogs in which performance is directly related to anatomical integrity and function.

Anatomy

The base of P1 articulates with the head of its corresponding metacarpal/tarsal bone at a dorsal angle slightly more than 90 degrees. In this position the first phalanx is almost parallel to the ground. P2 articulates with P1 forming a palmar/plantar angle of 135°. The superficial digital flexor tendon inserts on its proximal palmar/plantar aspect. Distally, P2 forms an obtuse dorsal angle with the shallow, sagitally concave articular surface of P3. The deep digital flexor tendon inserts on the broad palmar/plantar tubercle of P3. Each side of the tubercle is perforated transversely by a vascular bone tunnel. On the dorsal aspect of P3 there is another bony prominence, the ungual crest, which is the area of attachment of the extensor tendon and the dorsal elastic ligaments.

Clinical Examination

Variable degrees of lameness are usually present. Clinical examination reveals swelling that is often associated with crepitus and deformity of the affected phalanx. A thorough soft tissue evaluation is necessary to detect the presence of small wounds, some of which may arise from an open fracture.

Radiographic Examination

Radiologic evaluation of phalangeal injuries commences with plain radiographs. A minimum of two views taken at orthogonal angles provides information on two planes. Standard dorso palmar/plantar (DP) and lateral (L) views are the core of the radiologic assessment. DP views should include the metacarpo/ tarso–phalangeal joints and the distal inter-phalangeal joints.

The L view is taken with the toes spread in opposite directions with the aid of a stirrup of tape, applied on the nail of the second and fifth digit (“fan lateral”) (Figure 58-36A, B). Oblique views are used to increase the sensitivity of imaging of phalangeal fractures, especially in cases of severely comminuted fractures. A lateral view with traction applied to the nail is useful to assess the shape and size of the fragments in case of a comminuted fracture of P2.
 

Treatment Principles

To rationalize the treatment of phalangeal fractures it is necessary to take into account the anatomical characteristics of the area as well as the functional angles of the digits. Fractures of P1 and P2 are the most common, while fractures of P3 are less frequent.

In a survey on 40 phalangeal fractures affecting racing Greyhounds (un-published data) P1 was involved in 20 cases, P2 in 14 cases and P3 in 6 cases. P1 fractures were intra-articular in 6 cases P2 in 10 cases and P3 in all of the cases. The head of P1 was involved in 3 cases, in P2 the head was involved in 9 cases and the base of P1 in 3 cases.

Fractures of the Shaft

Fractures of the shaft of P1 and P2 can vary in configuration from: transverse, oblique, spiral with or without a butterfly fragment, to comminuted. Simple, stable non-displaced fractures, especially in young dogs, can be treated by closed reduction with splinting in a functional position.

Fractures with unstable configuration are best treated with open reduction and internal fixation with lag screws (1.5 mm to 2.0 mm) and/or mini plates applied on the dorsal or lateral aspect of the phalanges. In spite of the apparent simplicity of the surgical approach, internal fixation of complex fractures can be very challenging. Careful handling of the fracture fragments with appropriate instruments and gentle traction is mandatory in order not to compromise the delicate vascular structures in this area. Failure to respect the blood supply can lead to severe complications ranging from non-union to necrosis of the toe.

Fractures of P2 tend to displace due to the pull of the flexor tendons therefore the reduction of comminuted P2 fractures can be extremely challenging. A single screw is not sufficient to withstand rotational and shear stress. Ideally a minimum of two screws should be used for oblique fractures. Unfortunately this s not always possible due to the small size of the bones. An antirotational small K wire can be added to improve the stability. The screw head should be countersunk to avoid interference with the gliding tendons. When using mini plates, always try to secure two screws proximal and two screws distal to the fracture site. As this is possible only in very large breeds, one screw may be sufficient in selected cases, especially if the plate is applied in neutralization (Figures 58-37 and 58-38).
 

Fractures of the Base and Head

Fractures of the base or of the head are articular, and almost invariably involve the insertion of a collateral ligament. Fractures of the condyles can be handled with application of lag screws or with a loop of cerclage wire unless the fragments are too small to be safely secured in place. Very small fragments can be excised, but in cases with large unstable fragments involving the joint, amputation or arthrodesis is usually necessary.

Operative Considerations

Traditionally, the lag screw technique has been the gold standard for fixation of oblique, spiral and condylar fractures. This technique, which is relatively straightforward for most long bone fractures, can be technically challenging when attempting fixation of small bones. Despite the availability of very small implants (1.0 mm to 1.5 mm to 2.0 mm) the size remains large, relative to the phalanges and the fragments to be fixed… leaving little room for error.

The application of bicortical (positional) self-tapping screws eliminates one surgical step and eliminates the risk of losing reduction and of splitting the fragments during the tapping process. With bicortical screws the proximal cortex is not overdrilled and the screw threads achieve purchase in both cortices while reduction and compression are maintained with bone clamps.

Open Fractures

Open fractures are often comminuted and highly contaminated with severe soft tissue damage and with devitalized bone fragments protruding through the skin. In these cases, amputation is the best choice offering a good prognosis and for sporting dogs a rapid return to performance.

Fractures of P3

Fractures of P3 can involve the joint, split the phalanx obliquely or can occasionally involve the tuberosity of insertion of the deep flexor tendon or the ungual crest. Due to the small size of P3, attempts at internal fixation are unlikely to be successful and amputation is necessary.

Post Operative Considerations

Postoperative care following surgical repair consists of a padded bandage for 3 to 4 weeks and confinement for a total of 6 to 8 weeks. The bandage can be reinforced with a palmar/plantar splint for the first 2 weeks. After bandage removal and when radiographs confirm that the bone is healed, 3 weeks of limited exercise on a lead should commence, with a gradual increase in activity until a return to full activity is attained.

In the case of amputation, a light bandage is applied for 2 weeks. As soon as the swelling decreases and the reflected digital pad is properly sealed, it is possible to gradually reintroduce the dog to exercise. For sporting dogs, the return to full training following amputation is expected by 5 to 6 weeks postoperatively. The prognosis for uncomplicated cases is usually good to excellent.

Suggested Readings

Waibl H, Mayrhofer E, Matis U, Brunnberg L and Köstlin R: Atlas of Radiographic Anatomy of the Dog, Blackwell Publishing, 2003. 82-83 & 112-113.

Brinker, Piermattei and Flo: Fractures of Carpus, Metacarpus and Phalanges in: Handbook of Small Animal Orthopedics and Fracture Repair, 3rd ed. Philadelphia: W.B. Saunders 1997, 344-389.

Boemo C M: Injuries of the Metacarpus and Metatarsus in: Canine Sports Medicine and Surgery. Bloomberg M S,

Dee J F and Taylor R A. eds. W.B. Saunders 1998, 150-173. Dee JF: Fractures of Metacarpal and Metatarsal Bones in: AO Principles of Fracture Management in the Dog and Cat. Johnson AL, Houlton JEF and Vannini R. eds. AO Publishing 2005, 361-369.