A Retrospective Analysis of Lesser Metatarsophalangeal Joint Fusion as a Treatment Option for Hammertoe Pathology Associated with Metatarsophalangeal Joint Instability

Complex hammer digit deformity is commonly associated with instability of the metatarsophalangeal joint. Restoring joint stability is critical for digit alignment and function and can be challenging and unpredictable. Lesser metatarsophalangeal joint fusion might be an alternative treatment to the current soft tissue balancing, repair, and extra-articular osseous procedures used to treat joint instability. The present study was a retrospective chart and radiographic review of the pooled outcomes of 31 consecutive lesser metatarsophalangeal joint fusion procedures performed by 3 independent surgeons from May 2004 to September 2009. The clinical and radiographic outcomes were analyzed with descriptive and inferential statistics. The overall interval to radiographic union was 8.69 ± 1.7 weeks (range 6 to 12 and 95% confidence interval 7.9 to 9.4). The overall period to clinical union was 10.25 ± 4.5 weeks (range 4 to 22 and 95% confidence interval 8.5 to 11.9). The mean duration of non–weight-bearing was 4.71 ± 1.74 weeks, followed by 5.09 ± 2.8 weeks of guarded weight-bearing with a brace. Complications included nonunion in 4 (12.90%), hardware breakage in 2 (6.45%), and soft tissue infection in 1 (3.23%). Patients demonstrated a statistically significant reduction in pain (p = .035) and improved digit alignment after the procedure that enabled full return to unrestricted weight-bearing activities without limitations or the need for orthoses. These findings support metatarsophalangeal joint fusion as an alternative treatment of lesser digit metatarsophalangeal joint instability associated with hammer digit deformities that obviate the need for concomitant soft tissue procedures such as plantar plate repair or tendon balancing procedures.