Rigid iatrogenic hallux varus: a decades' worth experience with arthrodesis of the metatarsophalangeal joint.

Purpose: Arthrodesis of the first ray metatarsophalangeal joint (MPJ) is the gold standard in iatrogenic hallux varus (IHV) in the presence of stiffness and osteoarthritis. The purpose of this study is to collect clinical and radiographic results and complications of MPJ arthrodesis in rigid iatrogenic HV. Methods: A retrospective evaluation of rigid iatrogenic HV undergoing arthrodesis with a minimum follow-up (FU) of two years was performed. The clinical parameters assessed were visual analog scale (VAS), the AOFAS Hallux Metatarsophalangeal-Interphalangeal Scale score and the satisfaction scale. The radiological parameters evaluated the first to second metatarsal angle (IMA) and the angle of hallux valgus (HVA). Complications were also analysed. Result: A total of 18 patients (19 procedures) with a mean FU of 5.5 ± 2.5 years were included. The mean VAS improved from 7.3 ± 1.6 to 1.3 ± 1.2 (p < 0.05) at the last FU. Similarly, the AOFAS Hallux Metatarsophalangeal-Interphalangeal scale score significantly improved to 82 ± 9.2 (p < 0.05). Radiological evaluation demonstrated a 1–2 IMA improvement from 4.4 ± 2.2° preoperatively to 8.9 ± 2.4° at 3 months post-operatively. Similarly, there was a significant (p < 0.05) improvement of the HVA from − 22.7 ± 4.1° to 13.1 ± 4.1° at three months post-operative (p < 0.05). No signification loss of correction was noted at the last follow-up (p > 0.05). In one case, a delayed fusion at the arthrodesis site required surgical revision to promote fusion. No patient experienced pain with stress from the first MTP joint arthrodesis site or identified the arthrodesis site as a source of pain. No patient required implant removal. Re-operation and revision rates were 5.3%. The overall complications rate was 15.8%. Conclusions: MPJ fusion effectively corrects Iatrogenic Hallux Varus in cases of rigid and fixed deformities in the medium- to long-term follow-up, with lasting improvements in AOFAS and VAS scores. The procedure is characterised by a non-negligible risk of complications, reoperations and revisions. Level of evidence: Level IV, case series. [ABSTRACT FROM AUTHOR]