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

A 3-year-old male neutered tabby cat was referred for progressive weight-bearing lameness in the left pelvic limb. The cat had no outdoor access, and no traumatic event was reported. Two weeks of appropriate medical management was attempted by the referring veterinarian, with minimal improvement noted by the owner. On presentation at our clinic, the cat had a grade ⅗ left pelvic limb lameness, left thigh/gluteal muscle atrophy, and pain on manipulation of the left hip joint, with mild crepitus noted during range of motion assessment. A CBC and chemistry blood panel were normal. Radiographs revealed a chronic capital physeal fracture with intertrochanteric sclerosis, significant calcar bone resorption and mild osteoarthritic changes in the coxofemoral joint. A total hip replacement (THR) was performed utilizing BioMedtrix THR implants. A number 10 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 (#2 + 4 mm) revealed excessive joint laxity. A 4 mm BioMedtrix TPLO 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 and strength.

Acknowledgment

None.

 

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Publication History

Article published online:
15 July 2025