Surgical repair of coxofemoral luxation in a horse

Successful total hip arthroplasty in a miniature horse

OBJECTIVE

To describe the surgical treatment, postoperative management, and outcome of a miniature horse undergoing total hip arthroplasty (THA).

STUDY DESIGN

Case report.

ANIMALS

A 4-year-old miniature horse stallion weighing 85 kg.

METHODS

The horse presented with left coxofemoral luxation of ~6 weeks duration. Computed tomography confirmed craniodorsal luxation with marked degenerative changes to the femoral head. The horse underwent THA using cementless press fit implants, including an interlocking lateral bolt for the femoral stem.

RESULTS

The horse recovered well from anesthesia but suffered a coma-like episode after returning to a stable. Following treatment of presumed hypovolemia, the horse regained normal mentation and was discharged 24 days after surgery. At reassessment 12 weeks postoperatively, the horse was 2/10 left hind limb lameness at trot with good healing of the surgery site. Five months postoperatively mild (1/10) lameness remained at trot but the horse was able to canter normally on both reins. The horse has since been managed normally with no veterinary treatment required for 32 months postoperatively.

CONCLUSION

Total hip arthroplasty is possible in miniature horses weighing up to 85 kg and can result in a good long-term outcome.

Computer-assisted surgery for placing toggle constructs across the coxofemoral joints of small equids using a minimally invasive approach-A proof-of-concept cadaveric study

OBJECTIVE

To develop a minimally invasive technique for placing a toggle construct across the coxofemoral joint of small equids using computer-assisted surgery.

STUDY DESIGN

Experimental cadaveric study.

SAMPLE POPULATION

Three pilot specimens: One donkey, one Shetland pony and one Warmblood foal. Six main study specimens: Three Shetland ponies, one American Miniature Horse, one Warmblood foal and one donkey.

METHODS

Experimental surgeries were performed on both coxofemoral joints of each cadaver. Using a minimally invasive surgical approach, 5.5 mm bone canals were drilled through the femur and acetabulum, traversing the coxofemoral joint. Intraoperative guidance was provided by a cone-beam computed tomography (CBCT)-coupled surgical navigation system. A toggle construct was introduced through the bone canals. Surgical accuracy aberrations (SAA) were measured at the femoral entry and exit points and at the acetabular entry point on merged pre- and postoperative CBCT scans. The coxofemoral joint was assessed for articular cartilage damage by gross dissection.

RESULTS

A toggle construct was placed across all 18 coxofemoral joints. The overall median SAA in the main study was 2.8 mm (range: 0.4-8.0 mm). No cartilage damage was found in the cadaveric specimens of the main study.

CONCLUSION

The described technique allowed for the placement of a toggle construct across the coxofemoral joint of small equid cadaveric specimens without prior coxofemoral luxation.

CLINICAL RELEVANCE

This technique may serve as an option for surgical stabilization of coxofemoral joints in small equids. Further biomechanical investigations are required to assess optimal implant positioning and toggle constructs.

[Diagnostic procedures and treatment of a ventromedial coxofemoral luxation in sheep - Surgery and open reposition of a ventromedial coxofemoral luxation with a toggle-pin and iliofemoral sling fixation]

A 2.5-year-old female Valais black-nosed sheep was referred to the University Clinic for Ruminants at the University of Veterinary Medicine Vienna, with a history of sudden lameness after shearing. The sheep showed a moderate mixed lameness of the right hind limb, the hip joint area was painful on palpation; the pelvic limb was presented as stretched as possible. After the clinical examination, the suspected diagnosis of a right-sided hip joint dislocation was made, which was subsequently confirmed radiologically (luxatio ossis femoris dextra to caudoventral and medial). An open, manual reposition was performed under general anesthesia. A toggle pin was used as a prosthetic ligament replacement for the femoral head ligament, further stabilization was achieved by means of an iliofemoral loop fixation within the fascia of the gluteal muscles.The movement possibilities of the sheep during the postoperative healing phase were severely restricted and 8 weeks of stall rest were ensured. The healing process was uncomplicated. Telephone enquiry 6 months following the surgical intervention revealed that the sheep was free of lameness, kept up with the herd, and displayed a normal general condition.The success of surgery and the use of the procedure in livestock practice is limited by the necessity of rapid intervention after the trauma has occurred, the willingness of the animal owner to bear the costs associated with the operation under general anesthesia as well as to ensure the long post-operative follow-up care with controlled restriction of movement.

Modified toggle pin technique combined with prosthetic capsular reconstruction for surgical stabilization of coxofemoral luxation in a Shetland pony

OBJECTIVE

To describe open reduction and surgical stabilization of a coxofemoral luxation in a pony using a modified toggle pin technique and prosthetic joint capsule reconstruction without osteotomy of the greater trochanter.

ANIMAL

A 2-year-old Shetland pony with a bodyweight of 167 kg.

STUDY DESIGN

Case report.

METHODS

Radiographic examination confirmed craniodorsal luxation of the left coxofemoral joint. An open reduction with the aid of a pulley system was performed. A toggle pin was inserted through a bone tunnel extending from the level of the femoral shaft through the femoral head and the center of the acetabulum for the pin to be positioned on the medial wall of the acetabulum. FiberWire was subsequently passed through the cranial and caudal aspects of the acetabulum as well as a transverse tunnel in the femoral neck in a figure of 8 to facilitate capsular reconstruction. The pony was placed in a sling for 8 weeks and gradually returned to normal activity over 2 months.

RESULTS

Postoperative radiographic examination confirmed the position of the femoral head in the acetabulum with the implants in place. On 2-year follow-up the pony was sound at walk and trot.

CONCLUSION

A combined intra- and extra-articular stabilization technique for coxofemoral luxation in a pony resulted in successful long-term reduction and excellent outcome.

Risk factors for reluxation after toggle rod stabilization for treatment of coxofemoral luxation in 128 dogs

OBJECTIVE

Evaluate the risk factors for reluxation and outcomes for dogs with a toggle rod construct.

STUDY DESIGN

Retrospective case series.

ANIMALS

One hundred twenty-eight client-owned dogs.

METHODS

Medical records from 2007 to 2018 were reviewed for signalment, history, surgery, and outcome for dogs with a coxofemoral luxation repaired with a commercial toggle rod and nylon monofilament suture construct. Univariate and multiple logistics regression analysis were performed to assess risk factors associated with postoperative luxation. Primary veterinarians and owners were contacted for follow-up via telephone or electronic communication.

RESULTS

The overall complication rate was 24.2%, and the reluxation rate was 14.8%. There was a decreased risk of reluxation when the cause was traumatic in origin (odds ratio [OR] 0.10) or when the lameness was severe at presentation (OR 0.42). Fifteen of 58 (25.9%) owners contacted completed a follow-up survey.

CONCLUSION

Dogs with nontraumatic, low impact luxations were at a higher risk for reluxation.

CLINICAL SIGNIFICANCE

Dogs of any body condition with a traumatic coxofemoral luxation are at lowest risk for reluxation.

Successful Treatment of a Coxofemoral Luxation in a Shetland Pony by Closed Reduction and Prolonged Immobilization Using a Full-Body Animal Rescue Sling

A 12-year-old, 170 kg, Shetland pony mare was presented with an acute severe right pelvic limb lameness and concurrent upward fixation of the right patella. The affected limb was rotated externally and adducted with a prominent greater trochanter and the right calcaneal tuber being more proximal than its left counterpart. Radiographic examination revealed complete dislocation of the right femoral head from the acetabular cavity in a dorsal and caudal direction. A closed reduction of the coxofemoral luxation was performed successfully under general anaesthesia. A full-body animal rescue and transportation sling (ARTS) was applied for the recovery. The reduction was followed by a right-sided medial patellar desmotomy. The pony was supported in the ARTS for a total of eight weeks combined with crossties for the first six weeks. Subsequently, the mare was discharged with instructions to slowly increase walking exercise over a period of two months before returning to her intended use. A follow-up after 22 months attested the successful treatment of a coxofemoral luxation by closed reduction and prolonged immobilization resulting in a regularly exercised pony without any residual lameness.

Femoral head ostectomy for the treatment of acetabular fracture and coxofemoral joint luxation in a Potbelly pig

OBJECTIVE

To report the successful surgical treatment of a comminuted left acetabular fracture, a dorsally luxated left femoral head, and avulsion of the ligament of the femoral head by femoral head ostectomy (FHO) and physical therapy in a companion Potbelly pig.

STUDY DESIGN

Case report.

ANIMALS

A 1-year-old, 13 kg, castrated male, companion Potbelly pig.

METHODS

The pig presented with a nonweight bearing left pelvic limb lameness of 3 weeks' duration that was noticed shortly after the pig got caught under a fence. Under general anesthesia a lateral approach was made to the fractured limb. A FHO was performed as described for dogs. Following surgery, a period of physical therapy was initiated based on protocols described for dogs.

RESULTS

The canine surgical procedure with the approach modified for pigs was successfully performed in our pig. Following surgery, the pig was comfortable and weight bearing. A physical therapy regimen of supervised activity, stairs, and water therapy was used to rehabilitate the leg, as well as a weight management protocol to maintain ideal body condition. The owner was highly satisfied with the outcome. Telephone follow-up with the owner at 12 months after surgery revealed no impairment to movement, and the pig was maintaining normal ambulation without lameness. No complications were observed with this case.

CONCLUSION

FHO, as described for dogs, provided a favorable outcome for hip luxation caused by acetabular fracture, luxation, and avulsion of the femoral head ligament in this small size Potbelly pig.

Treatment of a coxofemoral luxation in a pony using a prosthetic capsule technique

OBJECTIVE

To report open reduction and joint stabilization using a prosthetic capsule technique for treatment of a craniodorsal coxofemoral luxation in a lightweight pony.

STUDY DESIGN

Clinical report.

ANIMALS

Pony stallion (8 years old, 113 kg).

METHODS

A craniodorsal approach to the coxofemoral joint was performed under general anesthesia. After open reduction, a prosthetic capsule technique was used. Four 3.5 mm self-tapping cortical anchor screws were implanted: 2 screws were inserted above the cranial aspect of the dorsal acetabular rim, and 2 screws were inserted into the femoral neck. Subsequently, a #5 USP ultra-high molecular weight polyethylene suture was placed through these anchor screws in figure-8 fashion to serve as a prosthetic capsule. Routine closure and a medial patellar desmotomy completed the surgical procedure. Postoperatively, the pony was cross tied for 4 weeks to prevent it from lying down.

RESULTS

Neither short-term nor long-term complications occurred and the pony was sound at the follow-up examination performed 15 months postoperatively.

CONCLUSIONS

A prosthetic capsule technique can be used successfully to stabilize the coxofemoral joint after open reduction of a craniodorsal luxation in a lightweight pony.

Ultrasonographic diagnosis of coxofemoral subluxation in horses

The clinical and ultrasonographic features of seven horses with coxofemoral subluxation are presented. Affected horses included five adult geldings (11-20 years), one large pony (6 years) and a 3-month-old filly. All were lame at the walk except for the pony with grade 3/5 lameness. Lameness was acute in all horses, but three horses progressed after initial improvement. Crepitus, muscle atrophy, and pelvic asymmetry were inconsistent findings. Ultrasonographic diagnosis of subluxation required dynamic visualization of femoral head displacement from the acetabulum while placing weight on the affected limb and subsequent replacement into its normal position upon limb resting. Acetabular rim fractures and joint effusion were visible regardless of weight bearing status in six horses each. No fractures were identified in the pony; the only patient with a good outcome. Six horses had a poor outcome with severe chronic lameness, four of which were euthanized. Postmortem ventrodorsal radiographs obtained in two horses confirmed subluxation only on extended limb projections, but not on hip-flexed projections. Acetabular rim fractures were not visible radiographically in either horse but were confirmed at necropsy. Subluxation was due to an elongated but intact ligament of the head of the femur in both horses. Osteoarthrosis was evident ultrasonographically, radiographically, and at necropsy. Dynamic ultrasonography was readily performed in the standing horse and produced diagnostic images with a low frequency curvilinear transducer. The apparent poor prognosis for horses with subluxation and acetabular fracture illustrate the importance of this imaging technique to identify affected horses.