The fate of the index metacarpophalangeal joint following pollicization

Purpose: To characterize the complications that occur at the index metacarpophalangeal (MCP) joint following pollicization and to identify the blood supply of the index MCP joint. Methods: Eighty-five pollicized digits in 74 patients (1974-2007) were followed after surgery and had documented clinical examinations and radiographs to evaluate physeal arrest, nonunion at the pollicized digit base, and instability of the new carpometacarpal joint at a minimum of 2 years following surgery. Results: Proximal phalanx physeal arrest was the most common complication. Radiographic nonunion at the juncture of the index metacarpal head and base occurred with and without instability. Twenty-one of 85 pollicized digits showed radiographic evidence of physeal arrest, 12 of which were complete and 9 partial. No clinical factor was found to significantly correlate with a physeal arrest, although the 9 patients with the diagnosis of Holt-Oram syndrome trended toward a higher percentage, with 6 digits in 5 patients with Holt-Oram syndrome showing this complication. Twenty pollicized MCP joints did not have bony union to the base of the index metacarpal, but only 3 were clinically unstable and required surgical stabilization. Ten pollicized digits developed some degree of instability and subluxation at the new carpometacarpal joint, but only one required surgical intervention. In recent cases, a search for the blood supply to the MCP joint has demonstrated a consistent vessel deep to the interosseous muscles that arborizes on the volar metacarpal neck. Our surgical technique has evolved to preserve this vessel whenever possible. Conclusions: Our complications are most likely due to technical factors. Careful dissection of the index MCP joint during pollicization should help reduce physeal growth arrest. Patients with Holt-Oram syndrome might have an increased risk of growth arrest. However, the majority of patients did not require secondary surgery and have good function. Type of study/level of evidence: Therapeutic IV.