33rd Annual Scientific Meeting proceedings

Introduction

Angular limb deformities are common in camelids and can be classified as congenital or acquired. Carpal valgus is most common and might be associated with limb rotation. Depending on the degree of deformity, conservative or surgical treatment is recommended. 3D-printed bones and guides have been recently described as helpful for surgical planning.

Case description

A 16-month-old, 46.5kg alpaca was presented for re-examination of a bilateral carpal valgus previously treated surgically with a transphyseal bridge using screws and wire. On admission, physical examination findings included lameness and difficulty getting up associated with a severe right carpal valgus of 42 degrees centred on the distal radial physis. Computed tomography, using dedicated software (Osiris), was performed to obtain a 3D evaluation of the deformity of the radius. A 3D bone model of the radius was printed and a custom saw-guide was then created to facilitate the wedge ostectomy. After ostectomy, the radius was stabilised with two standard 3.0-3.5-4.0mm FIXIN plates (V3043-V3044 and V3304). Short and long-term follow-up was available.

Results

Post-operatively, the alpaca remained comfortable. However, carpal hyperextension due to flexor laxity was observed. This was managed with controlled exercise and brace support. Recheck radiographs at 3 months revealed a 12-degree valgus of the right carpus. Long-term follow up after 12 months revealed a functionally and cosmetically satisfactory outcome with persistence of mild carpal hyperextension.

Discussion/conclusion

A 3D-printed bone model facilitated surgical planning. The use of a custom saw guide may improve the accuracy of wedge ostectomy, and outcome.