Crossed-screws provide greater tarsometatarsal fusion stability compared to compression plates.

Abstract

Hallux valgus is a common deformity that is often treated with a fusion of the first tarsometatarsal (TMT) joint. Crossed-screws are currently the accepted standard but advances in plate systems present opportunities for improved clinical outcomes; however, in vitro testing should be performed prior to clinical implementation. The purpose of this study was to determine whether a locking plate with surgeon-mediated compression provides similar fusion stability compared to crossed-screws and if bone density or joint size are related to construct success. Ten matched-pair cadaveric specimens received first TMT fusions with either crossed-screws or a compression plate and were loaded for 1000 cycles to assess the amount of joint motion measured as plantar gapping. Bone density was quantified using computed tomography images of each specimen, and joint height was measured with calipers. Crossed-screws provided 3 times greater resistance to plantar gapping compared to compression plates after 1000 cycles. Bone density and joint size did not affect resistance to plantar gapping for either construct. Lag screws or a plantarly applied plate are needed to maximize TMT fusion stability prior to osseous union. Dorsomedially applied plates are also effective when paired with a lag screw placed across the TMT joint. These constructs do not appear to depend on bone density or joint size, suggesting that patients with osteoporosis are viable candidates. The results of this study suggest that traditional, lagged cross-screws provide greater stability to that of a dorsally place compression plate and may lead to better rates of union. Therapeutic, Level V: Cadaveric Study.