Radiographic and Clinical Outcomes of Intramedullary Nails in the Modified Lapidus Procedure: A Retrospective Comparison with Dorsomedial Locking Plates.

BACKGROUND

The Lapidus procedure evolved into the first tarsometatarsal (TMT) arthrodesis, primarily used for treating severe hallux valgus, particularly in TMT arthritis or instability. Although effective, early techniques have high nonunion rates. Recent developments, including locking plate (LP) and intramedullary nail (IN) use, are aimed at enhancing fixation. LPs enable early weightbearing but may cause symptomatic hardware irritation. We hypothesized that IN fixation would yield better clinical and radiologic outcomes and fewer complications than LP fixation. In this retrospective study, we aimed to compare the radiographic and clinical outcomes of IN and LP fixation.

METHODS

Eighty-five patients (120 feet) underwent the modified Lapidus procedure between 2020 and 2023 and were retrospectively grouped according to the fixation type: IN and LP with a crossing screw. Three foot and ankle attending surgeons performed the procedures. Radiographic parameters (hallux valgus angle [HVA], intermetatarsal angle [IMA], and metatarsocuneiform angle [MCA]) were evaluated preoperatively, 2 months after initial weightbearing, and 1 year postoperatively. Clinical outcomes were measured using the Self-Administered Foot Evaluation Questionnaire (SAFE-Q), comprising 5 subscales scored out of 100.

RESULTS

Among the 64 patients (94 feet) analyzed, 57 and 37 underwent IN and LP fixation, respectively. At 1 year postoperatively, the amount of IMA correction from preoperative to 1 year was similar in both groups, but the IN group showed slightly lower IMA (95% CI: -3.57 to -0.22, P = .0265). HVA correction was similar between the groups; however, there was greater variability in the IN group. MCA changes indicated a comparable degree of correction loss between groups. SAFE-Q scores were statistically similar. The IN group experienced fewer complications (8.8%) compared with the LP group (22%). The LP group revisions mostly involved hardware removal.

CONCLUSION

In the modified Lapidus procedure, IN fixation demonstrated a slightly lower IMA at final follow-up and less hardware irritation compared with LP fixation. IN fixation should be considered an alternative to LP fixation.

LEVEL OF EVIDENCE: Level III, retrospective case control study.