Sessions

Coxofemoral joint luxation is uncommon in horses and the limited literature on clinical findings make diagnosis challenging. Most publications focus on ponies; minimal information is available on full-sized horses. The aim of the study was to aid recognition of coxofemoral luxation in horses, by providing detailed description of history, clinical presentation and gait patterns in cases with confirmed diagnosis (by diagnostic imaging and/or postmortem examination) of coxofemoral luxation.

Data were collected through a structured questionnaire distributed to veterinarians who had diagnosed coxofemoral luxation. Data included details on signalment, history, clinical examination, gait assessment, diagnostic imaging, outcome and postmortem evaluation. Descriptive data analysis was performed. Twelve cases with sufficient information were included in the study. Five horses presented with chronic lameness of ≥4 months’ – 4 years’ duration (mean 16 months). Subacute presentation consisted of two horses, ranging from 1 week to 3 months (mean 7 weeks). Five horses presented within a few hours to a few days after the onset of the lameness. One horse developed luxation during a traumatic recovery from general anesthesia. Five horses presented lame after routine activities such as bucking or jumping, and for six horses no events were noted. Atrophy of the gluteal, biceps and quadriceps muscles on the affected side was observed in six horses, all had subacute or chronic lameness. Soft tissue swelling over the coxofemoral region was noted in two cases with an acute onset of lameness. Eight horses exhibited outward rotation of the affected limb, proximal position of the tuber calcanei compared to the contralateral limb, and reduced range of passive motion of the coxofemoral joint. Six of these eight horses also exhibited a shortened caudal phase of the stride. Palpable and/or audible crepitus was detected in eight horses. Horses with acute and subacute onset of lameness showed severe to non-weight bearing lameness (7-8/8), while in horses with chronic lameness severity varied between 3-7/8. Diagnosis was confirmed using ultrasound and/or radiography in all cases. Seven horses were euthanized due to hopeless prognosis, one was retired and four were lost to follow-up. Post-mortem examination was performed in four horses. In addition to coxofemoral joint luxation, in two horses rupture of or damage to the femoral head ligament was observed.

In conclusion, common clinical features of coxofemoral joint luxation in horses include outward limb rotation, proximal position of the tuber calcanei, and gluteal, biceps femoris and quadriceps muscle atrophy. The duration of lameness before presentation can vary from hours to months. Although traumatic events may contribute to coxofemoral luxation, routine daily activities can also result in this injury. Our findings can contribute to early recognition and accurate diagnosis of coxofemoral joint luxation.