Minimal resection interposition arthroplasty of the first metatarsophalangeal joint.

Background: Interposition arthroplasty of the first metatarsophalangeal (MTP) joint is a viable alternative to fusion in patients with advanced hallux rigidus. The purpose of this study is to evaluate the midterm results of a modification of the technique.

Methods: Case series of 18 interposition arthroplasties were performed on 13 female patients with Grade III-IV hallux rigidus. The technique included cheilectomy, bunionectomy when needed, minimal resection of the base of the proximal phalanx and interposition of a fascia lata allograft in the first metatarsophalangeal joint. Mean follow up was nine years (range 75-136 months). Patients were evaluated according to the AOFAS score, the ability to tip toe and their subjective satisfaction.

Results: There was a significant difference between preoperative (mean 43.2, range 15-83) and postoperative (mean 77.3, range 40-100) AOFAS scores (p<0.001). The patients were able to tip toe on 12 of the 18 operated feet and 9 of the 13 patients were satisfied from the operation. All dissatisfied patients had a coexistent hallux valgus deformity.

Conclusions: The technique had satisfactory midterm outcomes in older patients with advanced hallux rigidus without hallux valgus. Advantages of the method are the preservation of tip toe function in most patients and a technically easy conversion to fusion when needed.