First metatarsophalangeal arthrodesis: a biomechanical comparison of three fixation constructs.

First metatarsophalangeal joint arthrodesis is utilized in the treatment of severe arthritis and hallux valgus. Successful fusion relies on limiting motion at the fusion site and may be achieved through numerous methods. Use of locking plates has recently generated considerable interest, but whether they provide any biomechanical advantage over other available constructs is unclear. Utilizing cyclic loading intended to mimic early weight bearing, the stiffness of three fixation methods for first metatarsophalangeal arthrodesis was compared using Sawbones. The one-third tubular plate completed 1.8 and 2.4 times more cycles before failure than the X-type locking plate or crossed screws, respectively. No difference was detected in cycles to failure between the X-type locking plate and crossed screws. One-third tubular plate mean stiffness was 49% greater than crossed screws at all cycles and greater than X-type locking plate by an average of 25%, beginning at cycle 50.