Clinical and Radiographic Outcomes of Nitinol Compression Staple Fixation for Midfoot and Chopart Arthrodeses: A Single-Centre Case Series

Introduction: Nitinol continuous compression staples are increasingly used for foot and ankle arthrodesis; however, real-world outcome data describing construct strategies, regional variation in union, and failure patterns remain limited, particularly for Chopart joints. Methods: A retrospective case series of consecutive adult patients undergoing midfoot or Chopart arthrodesis using nitinol compression staples as the principal fixation method was performed. Arthrodeses were classified as midfoot (tarsometatarsal and/or naviculocuneiform) or Chopart (talonavicular and/or calcaneocuboid). Fixation constructs were categorised as staple-only or hybrid (staples combined with screws and/or plates). Radiographic union was defined as ≥50% trabecular bridging on two orthogonal radiographs or confirmation on computed tomography. The primary outcome was union rate; secondary outcomes included time to union, complications, reoperation, construct configuration, and failure patterns. Results: Twenty-five arthrodeses were included (15 midfoot and 10 Chopart). Overall union was achieved in 22 of 25 procedures (88%). Union rates were higher in the midfoot cohort (14/15, 93.3%) than in the Chopart cohort (8/10, 80%). Median time to union among united procedures was 62 days (interquartile range: 47-80). Three non-unions (12%) and three complications (12%) occurred, with two procedures requiring further surgery. Staple-only constructs accounted for 20 procedures, with five hybrid constructs (four Chopart and one midfoot). One case of staple fatigue failure occurred at the bridge-leg interface. Conclusion: Nitinol compression staples provided reliable fixation for midfoot arthrodesis and acceptable outcomes in selected Chopart arthrodesis. Region-specific differences in union and failure patterns highlight the importance of construct planning and selective adjunct fixation for higher-risk Chopart constructs.