Single-incision percutaneous drilling technique to achieve hemiepiphysiodesis of the distal metacarpus in foals with metacarpophalangeal varus deformities.

Abstract

OBJECTIVE: To describe a drilling technique for hemiepiphysiodesis of the distal lateral metacarpal physis and report the outcome of treated foals. STUDY DESIGN: Retrospective case series. SAMPLE POPULATION: Eleven thoroughbred foals. METHODS: While horses were under general anesthesia, the lateral aspect of the distal metacarpal physis was approached through a single small incision by using a power drill. The drill bit was placed at the level of the physis under radiographic guidance. A 4.5-mm drill bit was passed several times through the lateral growth plate to remove the cartilage in a fan-like pattern. Postoperative outcomes consisted of clinical assessment and farm manager/owner satisfaction. Cosmetics and radiographic appearance of the surgical site were assessed when the horses were yearlings. RESULTS: The procedure was performed in 16 limbs of 11 thoroughbred foals with a median age of 113.5 days (range, 90-129). Median age at postoperative follow-up was 422 days (range, 366 to 452). The procedure stopped the progression of a metacarpophalangeal varus deformity in all the limbs treated, determined by visual clinical evaluation and farm manager's satisfaction with subjectively excellent radiographic images and cosmetic outcomes at yearling age. CONCLUSION: Physis ablation was consistently achieved in these 11 foals with developing growth deformities of the distal metacarpus. CLINICAL SIGNIFICANCE: This drilling technique may offer a minimally invasive, safe, and simple technique to manage distal limb conformation in foals without placement of implants. Additional quantitative data are required to assess its effectiveness relative to other options.