Surgical techniques for the treatment of hallux rigidus have evolved during the past decade. Previously, main treatments were cheilectomy for earlier stages of hallux rigidus and resection arthroplasty or arthrodesis for advanced stages. Although arthrodesis has been considered the "gold standard" for advanced hallux rigidus, in younger and more active patients, activity, functional, and shoe wear limitations are undesirable outcomes of this procedure. Alternative surgical procedures have been developed for advanced hallux rigidus, with varying outcomes and complications. Endoprosthetic replacement, which has been well described in the past and revisited recently, has higher complication rates than more traditional approaches. Hemiarthroplasty using various prosthetic resurfacings of the phalangeal base has been reported with variable success rates as well. Soft tissue interpositional arthroplasty has been shown to have inconsistent results and significant stiffness. The Arthrosurface HemiCAP prosthesis has been described for the treatment of full-thickness chondral and osteochondral defects of the shoulder, hip, and knee with high success rates to date. More recently, the technology was expanded to allow for metallic resurfacing of the first metatarsal head as an alternative technique with the potential to maintain motion and function. By using this implant alone or combined with soft tissue interpositional arthroplasty, or proximal phalanx osteotomies, even severe forms of hallux rigidus can be treated. During the past 30 months, the authors have treated more than 100 patients with hemiarthroplasty of the first metatarsophalangeal joint using the HemiCAP prosthesis (Arthrosurface Inc, Franklin, Mass). To date, there have been 2 failures, one from infection and the other from a related procedure. Twenty-five of the first 30 patients with stage II or III hallux rigidus consented to participate in a follow-up study. The mean age of these patients was 51 years. Mean follow-up was 20 months. The mean postoperative increase in range of motion of the joint was 42 degrees (baseline, 23 degrees; postoperative, 65 degrees). The mean American Orthopaedic Foot and Ankle Society and 36-item Short-Form Health Survey Questionnaire scores were 82.1 and 96.1, respectively. All patients were very satisfied with their results and said that they would have the procedure performed again. Although long-term follow-up is still needed, the short-term results are very promising. In addition, future treatment options are maintained because of minimal bone resection at the time of HemiCAP implantation, and conversion to arthrodesis or resection arthroplasty can be performed should the need arise.
