Use of a Spacer to Increase Soft Tissue Tension in a Feline Total Hip Replacement

A 3-year-old male neutered cat was referred for management of a chronic femoral capital physeal fracture. Significant secondary remodelling changes appreciated on radiographs included calcar bone resorption and intertrochanteric trabecular sclerosis. A total hip replacement was performed utilizing BioMedtrix total hip replacement implants. A number 10-mm BFx cup was implanted in an appropriate orientation. Given the loss of calcar bone, the osteotomy of the femoral neck was positioned further distal than ideal. Trial reduction of the monoblock femoral stem (number 2 +4 mm) revealed excessive joint laxity. A 4-mm BioMedtrix tibial plateau leveling osteotomy spacer was placed under the collar of the femoral stem to proximalize the stem, thereby resulting in appropriate tension across the joint. Follow-up radiographs at 8 weeks and 6 months postoperatively showed good osseous integration of the acetabular cup and a stable stem. The cat exhibited no hindlimb lameness or discomfort during hip manipulation. Hindlimb muscle symmetry and left hip range of motion indicated restored limb function.