Abstract

Introduction

Few reports of methods for managing luxations in birds have been published.² Coxofemoral luxations are frequently the result of trauma during restraint, or the bird struggling when its leg has been ensnared within a cage structure or fence. Elbow luxations primarily occur in raptors secondary to in-flight trauma.

For treatment of luxations, it is crucial to reduce the luxation as early as possible, which minimizes the formation of periarticular fibrosis. The bird’s attempts to use the injured extremity often—and very quickly—cause damage to the articular cartilage. In as brief as three days, clinically significant fibrosis occurs and inhibits reduction of the luxation and predisposes the joint to ankylosis. Where articular cartilage is damaged, even with successful luxation reduction and stabilization, it is likely that degenerative changes and osteoarthritis will occur in the future. As many animals with severe degenerative joint disease do not demonstrate overt pain, it is difficult to determine the clinical importance of osteoarthritis in older captive birds, and in free-ranging birds it is even more difficult to assess. Clinically significant arthritis may require years to develop during which time the bird likely will function well.

When managing luxations in birds, it is important to take radiographs after the extremity has been reduced and bandaged. During bandage application, re-luxation is common and must be identified immediately so that appropriate measures can be taken. Although controlled physical therapy under general anesthesia as early as possible will help minimize the effects of bandaging on other joints, it is best to wait 24–48 hours to allow healing to begin and pain to subside. In most cases, primary repair of the damaged tendons and ligaments is not possible so ultimately the joint becomes stable because of the formation of scar tissue. During physical therapy, no effort should be made to move the affected joint as if the scar tissue is disrupted by joint manipulations it may not stabilize. Therapy is generally performed under general anesthesia every other day and involves passive range of motion exercises of all immobilized joints, except the affected joint, for 10–15 min. For example, when managing an elbow luxation, the shoulder and carpus are exercised but not the elbow. Tendons and ligaments heal initially by a disorganized mass of fibrous connective tissue, which is not strong. When stresses are applied to the scar tissue, it reorients along the lines of stress. This process takes a long time (6–8 weeks in mammals). The conformation of many joints favors their remaining in a reduced position. While no objective data is documented on how long a joint should be immobilized before applying stress, if the support is removed too early, the joint will be more prone to reluxation. Generally, 7–10 days seems to be a long enough period for most joints to stay reduced after the support is removed.

It is vital to check the bandage daily if at all possible. Serious bandage morbidity can occur very quickly. In birds, damage to the propatagium can occur with figure-of-eight bandages. Part of physical therapy for wing injuries involves massaging the tendon and checking for injury from the bandage. Some birds are predisposed to developing pododermatitis when they must bear weight on only one leg. They also should be checked daily for early signs of bumble foot and appropriate treatment instituted as soon as signs are noted.

Luxation of the Shoulder

Shoulder luxation may involve avulsion of the ventral tubercle of the proximal humerus.² The shoulder joint is not a very stable joint and re-luxation is common. If the luxation occurs secondary to ventral tubercle avulsion, surgery to reattach the tubercle results in a stable joint. However, as the bone is fractured, it will take 3–4 weeks for healing. If the tubercle is not avulsed, closed reduction is often successful. If the joint does not stay reduced, a trans-articular pin can be placed through the proximal humerus along the deltoid crest and into either the scapula or coracoid. The pin should be placed with the shoulder joint held in a flexed (resting, folded wing) position. Regardless of the technique used, the wing should be bandaged to the body to immobilize the shoulder joint.

Elbow Luxation

Luxation of the elbow is usually the result of severe blunt trauma strong enough to disrupt the ligamentous support. This type of injury occurs infrequently in companion birds but has been reported to occur as frequently as in 12% of raptor patients.² Because of the anatomy, luxation usually occurs dorsal, caudal or caudodorsal. Ventral luxations generally occur only in association with fracture of the radius. The wing generally is held with the elbows extended (drooped) and externally rotated. Pain, crepitus, and swelling are noted on palpation of the affected wing. The wing should be examined for concomitant soft tissue injury that may affect the prognosis. The presence of open wounds and fractures has been associated with a poor prognosis for return to normal function.²

Reduction is accomplished by flexing the elbow to counteract the force of the scapulotriceps muscle that pulls the ulna caudally. Maintaining flexion, the radius and ulna are rotated internally while pressure is applied to the dorsal (lateral) aspect of the radial head to force it into apposition with the dorsal (lateral) humeral condyle. As the cubital joint is extended gently, a pop is often palpable when reduction is complete. In cases with severe ligamentous damage, this pop may not be palpable. If the joint is stable following reduction, it may be supported with a figure-of-eight bandage.

If closed reduction is not possible or re-luxation readily occurs, open surgical reduction is recommended. Through a lateral (dorsal) approach to the cubital joint, the common digital extensor is sutured to the scapulotriceps tendon distal to the cubitus. In a study that evaluated 12 cubital luxations in raptors, only three birds could be released.¹ Nine had caudodorsal luxation, none could be reduced closed and reduction was maintained using external skeletal fixation or figure-of-eight wrap. In another study, four of eight raptors with a cubital luxation were released.²

If the cubital joint can be reduced either open or closed, but it will not stay in reduction, a transarticular external skeletal fixation device may be applied to maintain reduction. At least two pins are placed in the humerus and two in the ulna. The elbow is flexed into a normal folded position and the pins connected.

Luxation of the Carpus

Usually the carpometacarpus is displaced dorsally relative to the radius and ulna. The bird will hold the wing with the carpus extended and it will be externally rotated at the carpus. Reduction is accomplished by applying traction and (dorsal) abduction of the distal extremity. The carpometacarpus is then toggled into reduction and the carpus is flexed and (ventrally) adducted. With the carpus in flexion a figure-of-eight bandage is applied to maintain reduction. With large birds or chronic luxations, open reduction may be indicated. In cases where laxity is present following reduction and the joint will not stay reduced, a transarticular pin or ESF device may be placed to maintain reduction. The transarticular pin is placed with the carpus in a normal degree of flexion through the main body of the carpometacarpus and into the ulna, which immobilizes the carpus. A fixator can be applied with two pins in the ulna and two in the major carpometacarpus.

Luxation of the Metacarpophalangeal Joint

Luxation has been reported in two raptors and both were treated by arthrodesis.⁸ The bones are small and blood supply tenuous in this location, which makes primary repair impractical. Both birds were treated with a type I external skeletal fixator and both regained full fight and were released.

Coxofemoral Luxation

In most psittacine birds and raptors, the coxofemoral joint is not a tight-fitting ball and socket joint. As a diarthrodial joint supported by a round ligament as well as collateral ligaments, it has a substantial amount of cranial to caudal gliding motion with little abduction and adduction. The ventral collateral ligament and the round ligament primarily are involved in maintaining the femoral head within the acetabulum. For luxation to occur, both of these structures must be disrupted.² In many species, the dorsal acetabular rim is well developed and extends as the antitrochanter to articulate with the broad, flat femoral neck and trochanter.

Coxofemoral luxations are generally the result of traction and rotational trauma, such as occurs when the leg is caught and the bird struggles to escape. Most luxations are craniodorsal in birds, although cranioventral luxation also has been reported.² Closed reduction and stabilization with slings, splints and casts have been recommended. In some cases, the luxation may be reduced and maintained using a transarticular pin. The pin is inserted through the trochanter into the head of the femur, across the joint and seated in the acetabulum. This pin must be inserted carefully by predetermined measure so to avoid injuring the kidney that lies medially to the acetabulum. The injured limb should be supported using an off weight bearing sling or spica splint to prevent pin migration. In most cases, sufficient production of scar tissue will occur 7–10 days postoperatively such that the pin safely may be removed. Long-term maintenance of a transarticular pin can predispose to the development of degenerative joint disease and pin migration.

Surgical reduction and stabilization is considered the treatment of choice for acute coxofemoral luxations. A femoral head and neck excision arthroplasty often is indicated for chronic luxations. The approach for both of these surgeries is the craniolateral approach that also allows for the placement of support sutures and access to the joint capsule.² In most cases, the joint capsule is torn or even absent as a result of the bird trying to walk on the affected leg. Following reduction of the luxation, stabilization sutures are placed from the trochanter to the dorsolateral iliac crest caudal to the central axis of the femur and from the trochanter to the cranial rim of the acetabulum.² The sutures are placed through the bone and with the stifle maintained in a normal standing position, the sutures are tightened. These sutures prevent excessive external rotation of the leg as with dorsal coxofemoral luxation, severe damage usually is present to the muscles that prevent external rotation. The joint capsule (if present) is closed and the iliotrochantericus caudalis and iliofemoralis externus are apposed. An alternative to open reduction is to perform a femoral head and neck excision arthroplasty (FHO).^2,4 For this technique, the rehabilitation is easier and the prognosis is generally good, even for raptors. By craniolateral approach to the hip, the head and neck of the femur are removed with an appropriate-sized osteotome or oscillating saw. Rongeurs should be used to ensure that no rough or sharp edges remain at the osteotomy site. Following FHO, a tendency for external rotation of the limb is often present because of the muscle damage caused by the luxation although this problem is not observed with femoral neck fractures.⁴ This issue can be countered using the support sutures described for surgical coxofemoral stabilization. In both situations, as polydioxanone suture remains for over 4 months in birds, but is absorbable, it is an appropriate choice for these anti-rotational sutures.

As with closed reduction, the limb should be supported postoperatively in a spica splint or off weight bearing sling for 7–10 days. It is best to maintain the bird in a cage with smooth walls and a perch near the floor to discourage the bird’s attempts to climb. It can be very difficult to achieve postoperative immobilization of the coxofemoral joint in long legged birds. Unlike with open reduction of a hip luxation, early use of the leg is encouraged following excision arthroplasty as a better pseudoarthrosis will form. Passive range of motion exercises can be started the day after surgery. In a recent report, a red-tailed hawk (Buteo jamaicensis) and a Canada goose (Branta canadensis) had virtually no lameness and normal function following FHO with good return to function within 12–48 hours postoperatively.⁴

Luxation of the Stifle

In addition to tearing the cruciate ligaments, damage to the collateral ligaments usually is present in birds with stifle luxation and multiple stifle ligament injury is frequent. During the physical examination, a positive drawer sign is elicited and medial and/or lateral collateral instability exists. The tibiotarsus may be located cranial or caudal to the distal femur. Surgical repair of the ligaments may be attempted, especially in large birds; however, in most birds, the size of the ligaments precludes primary surgical apposition.

If the stifle can be reduced closed, a transarticular ESF may be used to maintain the stifle in reduction allowing periarticular fibrosis to stabilize the joint. Two fixation pins minimally should be placed each in the femur and the tibiotarsus. With the joint reduced and the limb in a normal, standing position, the pins are connected.⁷

If the joint cannot be reduced closed, an open reduction is indicated. A lateral parapatellar approach to the stifle is made and a curved hemostat is used to lever the proximal tibiotarsus into its proper position on the distal femur. Once the joint is reduced, several options to maintain reduction are described. A transarticular pin can be placed from the distal femur into the proximal tibiotarsus to hold the joint in reduction. During closure, the joint capsule is imbricated. The leg is bandaged for 10–14 days to allow fibrous tissue to stabilize the joint before the pin is removed. In one report, cruciate ligament and stifle luxation were managed with open reduction and stabilization⁵ with one bird (trumpeter hornbill, Bycanistes bucinator) repaired by a fibular head transposition and lateral joint imbrication for cruciate ligament damage and the other bird (African grey parrot, Psittacus erithacus) stabilized by lateral imbrication after open reduction. Both birds regained good limb function by 30 days. In these birds, no external coaptation was used, allowing early return to function, which is preferred if the joint is stable after soft tissue repair.

Alternatively, a hole can be created from lateral to medial in the distal femur and proximal tibiotarsus. A suture is passed from lateral to medial in the distal femur and medial to lateral in the proximal tibiotarsus. This approach will create a mattress suture that will mimic the collateral ligaments that are often damaged with stifle luxation. The joint is reduced, and the suture tightened. Unfortunately, this suture may not stabilize cranial-caudal movement (drawer), so a transarticular pin, an external fixator, or a bandage can be added to prevent cranial-caudal movement. A third option is to perform an open reduction and place a transarticular fixator with at least two pins each in the femur and the tibiotarsus connected on the lateral aspect of the leg. Once the fixator is applied, soft tissues are imbricated to provide support and scaffolding for scar tissue formation. Finally, a technique described for use in young birds with developmental stifle luxation involves inserting a pin normograde from distal to proximal into the femur and another proximal to distal into the tibiotarsus.³ These pins are left long and used to align and reduce the luxation. The stifle is placed in a normal standing angle and the pins will cross. Cement is used to bond the two pins cranial to the stifle externally. A disadvantage of this technique is that the pins penetrate the articular cartilage and are exposed externally. In one report, ascending osteomyelitis occurred and ended in amputation.⁶

Where severe damage is present with these articular fractures, arthrodesis may be indicated. Successful arthrodesis and good limb function were reported in a cockatoo (Cacatua moluccensis) with a traumatic stifle luxation.⁷ When an arthrodesis is performed, the fixator is maintained until evidence of bony union is present radiographically.

Prognosis with avian luxation repair is somewhat dependent on the intended use of the bird. Companion birds and zoo specimens may function without a precise ability to fly; however, with wild birds, hunting birds, and racing pigeons, anything less than perfection cannot be regarded as success. In many birds, some degree of leg dysfunction may be acceptable; however, in raptors, legs are important for obtaining food; in terrestrial birds, they are necessary for survival; and in many species, they are vital for successful reproduction.

Literature Cited

1.  Ackermann, J., and P. Redig. 1997. Surgical repair of elbow luxations in raptors. J. Avian Med. Surg. 11:247–254.

2.  Bennett, R.A., 1997. Orthopedic surgery. In: Altman, R.B., S.L. Clubb, G.M. Dorrestein, and K. Quesenberry (eds.). Avian Medicine and Surgery. W.B. Saunders Co. Philadelphia, Pennsylvania. Pp. 733–766.

3.  Bowles, H., and D.W. Zantop. 2002. A novel surgical technique for luxation repair of the femorotibial joint in a monk parakeet (Myiopsitta monachus). J. Avian Med. Surg. 16:34–38.

4.  Burgdorf-Moisuk, A., J.K. Whittington, R.A. Bennett, M. McFadden, M. Mitchell, and R. O’Brien. 2011. Successful management of simple fractures of the femoral neck with femoral head and neck excision arthroplasty in two free-living avian species. J. Avian Med. Surg. 25:210–215.

5.  Chinnadurai, S., G. Spodnick, L. Degernes, R.S. DeVoe, and D.J. Marcellin-Little. Use of an extracapsular stabilization technique to repair cruciate ligament ruptures in two avian species. J. Avian Med. Surg. 23:307–13.

6.  Harris, M. C., O. Diaz-Figueroa, S.K. Lauer, B. Burkert, and T.N. Tully. 2007. Complications associated with conjoined intramedullary pin placement for femorotibial joint luxation in a Solomon Island Eclectus parrot (Eclectus roratus solomonensis). J. Avian Med. Surg. 21:299–306.

7.  Rosenthal, K., E. Hillyer, and D. Mathiessen. 1994. Stifle luxation repair in a Moluccan cockatoo and a barn owl. J. Avian Med. Surg. 8:173–178.

8.  Van, A.J., and P.T. Redig. 2004. Arthrodesis as a treatment for metacarpophalangeal joint luxation in 2 raptors. J. Avian Med. Surg. 18:23–29.