2.1

We conducted a retrospective review of all patients who underwent FMTPA at our center from 2016 to 2023. Five experienced foot-and-ankle surgeons were involved in the surgeries. Indications included: stage 3 or 4 hallux rigidus, severe hallux valgus deformity (HVA > 40° or intermetatarsal angle (IMA) > 20°) with degenerative changes, and rheumatoid degeneration with advanced osteoarthritis . Only patients treated with one of the three fixation methods and with a minimum clinical and radiographic follow-up of 12 months were included. Demographic characteristics, medical comorbidities and additional procedures were collected. Ethical approval was obtained prior to the study (PI-6410).

A total of 110 FMTPA procedures were performed in 102 patients, 79 women and 31 men, with a mean age of 66 years (range 31–88), and mean follow-up of 41 months (range 12–156). Fifty patients (45%) had comorbidities: 21 with diabetes, 16 were active smokers and 13 were on immunosuppressive therapy. Surgical indications were hallux rigidus in 79 patients (72%), hallux valgus in 21 (19%) and rheumatoid degeneration in 10 (9%). All procedures were performed supine using popliteal nerve block and an ankle tourniquet. Fixation methods included dorsal locking plate with lag screw (Anchorage, Stryker®) in 74 feet (67%), two pre-bent staples in orthogonal configuration (Easyclip, Stryker®) in 28 (25%) and two solid crossed-compression screws in 8 (7%). Table 1 displays the distribution of fixation methods by diagnosis. Additionally, 53 concomitant procedures (48%), most commonly second and third metatarsal shortening osteotomies, were performed on lesser toes.

2.2

A medial linear incision centered on the MTP joint allowed longitudinal capsulotomy and subperiosteal exposure. Osteophytes were resected, joint surfaces prepared, and adhesions released via plantarization of the phalanx. Guidewires were placed in the metatarsal and phalanx, followed by cup-and-cone reaming of the articular surfaces ( Fig. 1 ). The hallux was aligned to 10–15° valgus, 25–30° dorsiflexion, and neutral rotation, temporarily fixed with wires on a flat surface simulating weight-bearing ( Fig. 2 ). After definitive fixation, capsular and layered soft-tissue closure was performed. Patients began weight-bearing in an orthopedic shoe on postoperative day one.

Preparation of the articular surfaces with cup-in-cone reamers and perforations. Desired alignment temporarily fixed with wires.

Definitive fixation of FMTPA with plate and screws and with orthogonal staples.

2.3

Clinical outcomes included foot pain using a VAS scale and transfer metatarsalgia throughout the follow-up. Functional assessment was performed using the European Foot and Ankle Society (EFAS) score. Complications included hardware-related pain, wound healing disturbances, and the need for revision surgery.

Weight-bearing anteroposterior and lateral radiographs were evaluated preoperatively, at 6 weeks post-operatively, and at final follow-up ( Figs. 3 and 4 ). Radiographic analysis included union rate, HVA, IMA and DFA.

From left to right, AP weight-bearing x-ray of FMTPA fixed with plate and screws, staples and crossed screws. Additional procedures were performed on the lesser metatarsals.

From top to bottom, lateral weight-bearing x-ray of FMTPA fixed with plate and screws, staples and crossed screws.

2.4

Statistical analysis was performed with the SPSS Statistics program (version 26.0; IBM, Armonk, NY, USA). A normality analysis of the continuous quantitative variables was carried out. Continuous quantitative variables with a normal distribution were presented as mean and standard deviation, while categorical variables were presented as absolute frequencies and proportions. Effect sizes for categorical variables were expressed as odds ratios with 95% confidence intervals. Comparisons between categorical variables were performed using the chi-square test. For contingency tables with low expected frequencies, logistic regression was applied. For quantitative variables 2 ° of freedom omnibus ANOVA test was performed, followed by a post hoc Bonferroni correction for multiple comparisons. Statistical significance was set at p < 0.05.

3.1

At final follow-up, 25 patients (23%) reported hallux pain, with a mean VAS of 1.9 (range 0–6). Transfer metatarsalgia was developed in 22 patients (20%), of whom 15 (68%) received initial surgery on the lesser metatarsals. Additionally, 49 patients (44%) had hip, knee, or spine osteoarticular conditions that could influence gait disturbances. The mean EFAS score was 29 (range 11–40). No differences were found between fixation techniques in the incidence of transfer metatarsalgia (p = 0.85), pain (p = 0.82), or mean EFAS score (p = 0.95) ( Table 2 ).

3.2

Radiological results are shown in Table 3 . Eleven patients (10%) showed nonunion, of which 9 received a plate and screws (12%) and 2 were operated with staples (7%). All patients treated with crossed-screws achieved fusion. Most nonunions were asymptomatic, but 3 patients reported pain. No differences were found in nonunion rates according to the technique (p = 0.46) or diagnosis (p = 0.66). Only 2 patients with nonunion had associated medical comorbidities.

No differences were found between fixation groups in HVA (p = 0.18) or IMA (p = 0.38). The mean DFA in the immediate postoperative period was 19 ± 10º, and 18 ± 11º at final follow-up. Significant differences in DFA were observed between groups. Patients with plates and screws had a more adequate postoperative DFA (26 ± 9°, p = 0.01) and at final follow-up (25 ± 8°, p = 0.03), compared to the other groups ( Table 3 ).