Femoral angular correction and lengthening in a large-breed puppy using a dynamic unilateral external fixator.

Objective: To report treatment of a large-breed puppy with combined distal femoral valgus and length deficit caused by partial distal physeal closure.

Methods: Clinical report. Methods: Bernese Mountain Dog (4.5-month-old male). Methods: The puppy was admitted for evaluation of a progressive severe left pelvic limb lameness (grade 3/4) of 6-week duration. Distal femoral valgus and severe length deficit deformity were treated by acute angular correction using a closing wedge ostectomy and progressive rapid-rate callus distraction using a dynamic, telescoping unilateral External Skeletal Fixator (ESF) designed for people. After acute angular correction and a 3-day latency period, a mean linear distraction rate of 3 mm/day was maintained for 3 weeks. The dynamic ESF (dESF) was removed at 4 weeks, after a 1-week consolidation phase.

Results: The dESF was stable and functional during distraction and bone healing. Distal femoral valgus conformation improved 50° (from 41° to 91°) and femoral length increased 42 mm at dESF removal (from 158 mm to 200 mm; 27%). After cessation of bone growth, no valgus and minimal (6%) length deficit were detected. At 4, 5, 6, 12, and 24 months after surgery, the dog was walking, trotting, and galloping normally.

Conclusions: Acute angular correction and progressive rapid-rate callus distraction using a unilateral dESF allowed satisfactory treatment of combined distal femoral valgus and length deficit in a large-breed puppy.