Plate-mediated versus lag screw-driven compression in first metatarsophalangeal joint arthrodesis for end-stage hallux rigidus: A retrospective comparative cohort study

Abstract

Objective: To compare two technical sequences using the same fixation construct but differing in the mechanism responsible for primary compression across the arthrodesis site. Methods: A retrospective cohort study was performed including consecutive patients who underwent first metatarsophalangeal joint (MTPJ) arthrodesis for advanced hallux rigidus (Coughlin and Shurnas grades 3 and 4) between January 2015 and December 2024. All procedures were performed using cup-and-cone joint preparation, a low-profile dorsal plate, and an oblique cannulated screw. In technique 1 (T1), compression was generated primarily through the dynamic compression mechanism of the dorsal plate, whereas in technique 2 (T2), compression was generated primarily by the oblique lag screw. Clinical outcomes were assessed using the American Orthopaedic Foot & Ankle Society (AOFAS) hallux metatarsophalangeal-interphalangeal scale and the visual analog scale (VAS) for pain. Radiographic union, time to union, and complications were recorded. Results: Fifty-five patients (68 feet) were included, comprising 39 feet treated with T1 and 29 feet treated with T2. Both techniques resulted in significant improvements in AOFAS and VAS scores (p < 0.001 for all comparisons). Nonunion occurred in 3 of 39 feet (7.7%) in T1 and 1 of 29 feet (3.4%) in T2 (p = 0.631). No statistically significant differences were observed between groups regarding final AOFAS scores, final VAS scores, or overall complication rates. Mean time to union was significantly shorter in T2 than in T1 (6.89 ± 0.79 vs 7.94 ± 1.17 weeks; p < 0.001). After adjustment for age and baseline clinical differences, T2 remained independently associated with faster union (adjusted coefficient -0.80 weeks; 95% confidence interval, -1.46 to -0.15; p = 0.015). Conclusions: First MTPJ arthrodesis using a dorsal plate combined with an oblique cannulated screw provided reliable union, substantial pain relief, and significant functional improvement regardless of the sequence of implant application. Although both compression strategies yielded comparable union rates and clinical outcomes, lag screw-driven compression was associated with a significantly shorter time to fusion. These findings suggest that direct interfragmentary compression generated by the oblique lag screw may modestly accelerate arthrodesis consolidation without increasing complications. Level of Evidence III; Retrospective Comparative Cohort Study.