Clinical and radiological outcomes of an in-situ lengthening, bipolar implant for radial head arthroplasty

Background: An in-situ lengthening, bipolar radial head arthroplasty can be an effective treatment for radial head fractures. Methods: We retrospectively reviewed 24 consecutive patients with radial head fractures or malunions from 2007 to 2012 who were treated with an in-situ lengthening, bipolar radial head arthroplasty. We included all patients, regardless of concomitant injuries. Patients in the long-term group (> one year, n = 14) returned for follow-up at an average of 33 months; patients in the short-term group (< one year, n = 8) returned at an average of seven months. Two patients were lost to follow-up. We assessed each patient's clinical and radiographic outcome. Results: In the long-term group, the mean Mayo Elbow Performance Index (MEPI) was 87.5, nine of 14 patients had lucency around the shaft of the implant, average proximal migration of the stem was 1.12 mm, and eight patients developed heterotopic ossification. In the short-term group, the mean MEPI was 79.4, five of the eight patients had lucency around the shaft of the implant, average proximal migration of the stem was 1.06 mm, and six patients developed heterotopic ossification. The two patients lost to follow-up did have revision surgery to remove the implant. Conclusions: This study indicates that an in-situ lengthening, bipolar radial head implant can be an effective option for treating radial head pathology. The formation of small amounts of ectopic bone about the implant is common, but reoperation for revision of the implant did occur in two patients in our series.