How to Provide Limb Stabilization for Orthopedic Emergencies

1. Introduction

Orthopedic trauma associated with bone fracture, joint luxation, or complete loss of tendon or ligament support can be life threatening if it is not managed promptly and appropriately after the injury. An unstable limb can rapidly induce further trauma, which can markedly decrease the chance for a successful repair and survival. Therefore, the goal of limb stabilization is to prevent additional trauma that may result in eburnation of fracture ends, fragmentation and fracture displacement, damage to neurovascular structures, skin penetration leading to an open fracture, and additional soft tissue damage [1-3].

2. Materials and Methods

Patient Assessment

Initial assessment includes determining the hydration status, cardiovascular function, and bony column stability as well as identifying the specific bone(s) or soft tissue(s) involved, the open or closed nature of the fracture, and the synovial structure involved. Analgesics and sedatives such as xylazine hydrochloride [a] (0.2 - 0.5 mg/kg, IV), romifidine hydrochloride [b] (0.04 - 0.10 mg/kg, IV), or detomidine hydrochloride [c] (0.005 - 0.020 mg/kg, IV) are important to relieve anxiety, alleviate pain, and minimize further self-inflicted damage to the injured limb. Caution should be exercised when administering these agents to prevent the horse from becoming ataxic. Sedatives and analgesics are contraindicated in the presence of dehydration and hypovolemia to avoid cardiovascular deterioration. Phenylbutazone [d] (2.2 - 4.4 mg/kg, IV), flunixin meglumine [e] (1.1 mg/kg, IV), or ketoprofen [f] (1.1 mg/kg, IV) should be administered to help reduce inflammatory pain at the injury site and ameliorate anxiety. Broad-spectrum antibiotics should be administered in the presence of skin penetration, synovial-structure involvement, or disruption of soft tissue supporting structures. Tetanus prophylaxis should be updated if the vaccination status is unknown. Wounds should be lavaged with sterile polyionic fluid to remove gross debris and decrease bacterial contamination. Topical antiseptics and/or antimicrobials may also be applied to wound sites (that are not located directly over synovial structures) before placing a sterile dressing and stabilizing the limb.

Equipment and Limb Stabilization

The key to orthopedic first aid is appropriate limb stabilization immediately after examination of the patient and the condition of the affected limb. Radiographs can be taken after limb stabilization. Splinting can be performed effectively with simple equipment in field situations when attention is given to proper technique [2]. The basic method of stabilization is a splint applied over a uniform layered bandage; this decreases interfragmentary movement and provides an intact strut for weight bearing. Commonly used splints include split polyvinyl chloride pipe (e.g., 4-in schedule 40 pipe sectioned longitudinally into one-third pieces), wood (e.g., 1 × 4-in broom handles or pitchfork handles), metal rods (e.g., aluminum or concrete reinforcing bar), or any light-weight rigid object available on the farm. Sharp splint edges should be rounded and may be wrapped tightly with padding. In addition, external coaptation using fiberglass cast material can provide a rigid circumferential weight-bearing surface, and it is easily penetrated for radiographs. In general, effective stabilization requires immobilization of the joint above and below the fracture site [1,3]. Under no circumstances should a splint end at the same level as the fracture, because the splint will act as a fulcrum, which will create further disruption at the fracture site [3]. The specific mode of immobilization differs along the limb according to the locally predominant biomechanical forces. Both forelimbs and hindlimbs can be divided into the following four functional sections (Fig. 1) [1].

Thoracic Limb

Section 1: Ground to the Distal Metacarpal Metaphysis

The goal of splinting in this region is to align the dorsal cortices of bones in a straight line to neutralize the dorsopalmar bending force. A light half-limb bandage (≤0.5-in thick) that accommodates swelling of the limb under the splint without allowing excessive motion at the fracture site is recommended [3]. A splint extending from the toe to the proximal metacarpus is taped to the dorsal surface of the limb using non-elastic tape or cast material (Fig. 2); this may be facilitated by having an assistant hold the carpus in slight flexion. Alternatively, a Kimzey Leg Saver Splint [g] can be applied (Fig. 3).

Figure 1. Thoracic limb: (1) ground to the distal metacarpal metaphysic, (2) middle metacarpus to the distal radius, (3) middle and proximal radius, and (4) proximal to the cubital joint. Pelvic limb: (1) ground to the distal metatarsal metaphysic, (2) middle metatarsus to proximal metatarsus, (3) tarsus and tibia, and (4) proximal to the stifle. (Modified from Manual of Equine Field Surgery with permission from Elsevier.) To view click on figure

Figure 2. Section 1: forelimb. A single dorsal PVC splint extending from ground to the proximal metacarpus has been applied to align the dorsal cortices of the distal forelimb. To view click on figure

Figure 3. Section 1: forelimb. A Kimzey splint can be used as an alternative for injuries involving the distal forelimb. To view click on figure

Figure 4. Section 2: forelimb. Caudal and lateral wooden splints have been applied from the ground to the level of the elbow joint. To view click on figure

Section 2: Middle Metacarpus to the Distal Radius

The goal of splinting this region is to maintain alignment of the bony column and immobilize the limb distal to the fracture site. A moderately thick full-limb bandage, approximately three times the diameter of the limb, should be applied in multiple layers that are tightened with gauze. It is crucial that the bandage is uniform in shape and tight enough to achieve maximum stability and rigidity of the splinted limb while avoiding excessive focal skin pressure. Caudal and lateral splints extending from the ground to the elbow joint are applied and tightly secured using non-elastic tape (Fig. 4).

Section 3: Middle and Proximal Radius

The goals of stabilizing radius fractures are to prevent limb abduction and to avoid penetration of the soft tissue along the medial aspect of the antebrachium by the fractured bone ends. A moderately thick full-limb bandage as described above should be applied. A caudal splint extending from the ground to the elbow joint and a lateral splint extending from the ground to lie against the lateral aspect of the shoulder are applied and tightly secured using nonelastic tape (Fig. 5).

Figure 5. Section 3: forelimb. A caudal polyvinylchloride (PVC) splint has been applied from the ground to the elbow joint, and a lateral wooden splint has been applied that extends from the ground to lie against the lateral aspect of the shoulder. To view click on figure

Section 4: Proximal to the Cubital Joint

Fractures of the olecranon, humerus, and scapula result in the loss of the triceps’ muscle-tension apparatus and the ability to fix the carpus into extension. Fractures in this region are well protected by overlying musculature and generally do not require stabilization. A light full-limb bandage combined with a caudal splint spanning the carpus will enable weight bearing and improve balance on the affected limb (Fig. 6).

Figure 6. Section 4: forelimb. A caudal PVC splint has been applied from the metacarpophalangeal joint to the elbow joint to help lock the carpus into extension. To view click on figure

Figure 7. Section 1: hindlimb. A plantar PVC splint extending from the toe to the proximal metatarsus has been applied to align the solar surface of the foot, plantar aspect of the metatarsophalangeal joint, and the flexor tendons. To view click on figure

Pelvic Limb

Section 1: Ground to the Distal Metatarsal Metaphysis

The goal of splinting in this region is to align the dorsal cortices of bones in a straight line to neutralize the dorsoplantar bending force. A light half-limb bandage is applied. Because of the hindlimb reciprocal apparatus, it is easier to align the solar surface of the foot, the plantar aspect of the metatarsophalangeal joint, and the flexor tendons than it is to align the dorsal cortices [3]. Therefore, with proper alignment, a splint extending from the toe to the proximal metatarsus is applied along the plantar aspect of the limb (Fig. 7). Alternatively, a Kimzey Leg Saver Splint can be used.

Section 2: Middle Metatarsus to Proximal Metatarsus

The goal of splinting this region is to maintain alignment of the bony column and immobilize the limb distal to the fracture site. A moderately thick full-limb bandage, approximately three times the diameter of the limb, should be applied in multiple layers that are tightened with gauze. It is crucial that the bandage is uniform in shape and tight enough to achieve maximum stability and rigidity of the splinted limb while avoiding excessive focal skin pressure. Plantar and lateral splints extending from the ground to the calcaneal tuber are applied and tightly secured using non-elastic tape. The lateral splint may extend to the level of the stifle for more proximal fractures (Fig. 8).

Section 3: Tarsus and Tibia

The goals of stabilizing tarsus and tibia fractures are to prevent limb abduction and to avoid penetration of the soft tissue along the medial aspect of the tibia by the fractured bone ends. Fractures in this region are particularly difficult to immobilize because of the reciprocal apparatus; additionally, stifle flexion leads to fractured bone-end overriding [1]. A moderately thick full-limb bandage as described above should be applied. A lateral splint extending from the ground to the level of the tuber coxae should be applied and tightly secured using nonelastic tape (Fig. 9). The splint should be made from a wide (4 - 8 in) piece of wood or a metal rod bent back on itself in the shape of the tarsal and stifle angulations. Fiberglass cast material can be wrapped around the shaped metal rod for additional strength. Placing the limb in extension and caudal to the normal limb facilitates bandage and splint application [3]. In foals that have sustained proximal tibial physeal fractures, bandaging should be avoided. Heavy coaptation may cause further damage by acting as a fulcrum; consequently, this can distract the fragment ends and potentially cause medial skin penetration.

Figure 8. Section 2: hindlimb. A caudal PVC splint has been applied from the ground to the calcaneal tuber, and a lateral wooden splint has been applied from the ground to the level of the stifle joint. To view click on figure

Section 4: Proximal to the Stifle

Fractures proximal to the stifle do not require splinting because of the extensive muscle coverage that provides effective fracture stabilization. Bandage and splint application for fractures in this region could directly increase fracture-site trauma by creating a pendulum effect.

Preparation for Referral

In most cases, it is advisable to discuss referral and surgical options with the client only after the patient is relatively calm and the limb is properly stabilized. The nearest surgical facility should be contacted and consulted before transportation. Euthanasia is definitely indicated in certain situations. However, in most cases, patient and limb stabilization followed by consultation with the nearest surgical facility will provide the best service to the horse and the client. The horse should be transported in a confined area with minimal space for body movement and adequate room for head motion and foot placement to aid in balance. A horse with an injured forelimb should face backward, and a horse with a hindlimb injury should face forward to prevent additional stress on the injured limb during emergency stops. Providing distraction by offering a small amount of hay during transportation is recommended. Young foals should be supervised by an attendant during transport and placed in a partitioned area adjacent to the dam.

Figure 9. Section 3: hindlimb. A lateral wooden splint has been applied from the ground to beyond the level of tuber coxae. To view click on figure

3. Results and Discussion

Although many factors are associated with successful outcomes, management of orthopedic emergencies begins before the horse is ever assessed by a surgeon. Therefore, it is imperative that appropriate first aid and proper splint application are performed immediately after the injury to improve the chances of a successful outcome.

Footnotes

[a] Rompun 10% injection, Bayer Animal Health, Shawnee Mission, KS 66201
[b] Sedivet 1% injection, Boehringer Ingelheim, St. Joseph, MO 64506
[c] Dormosedan 1% injection, Pfizer Animal Health, Exton, PA 19341
[d] Phenylbutazone (2.2 - 4.4 mg/kg, IV) 20% injection, Butler Animal Health, Dublin, OH 43017
[e] Banamine 5% injection, Schering-Plough, Kenilworth, NJ 07033
[f] Ketofen 10% injection, Fort Dodge Animal Health, Fort Dodge, IA 50501
[g] Kimzey Leg Saver Splint, Kimzey Welding Works, Woodland, CA 95695