Does arthrodesis of the first metatarsophalangeal joint correct the intermetatarsal M1M2angle? Analysis of a continuous series of 208 arthrodeses fixed with plates

AbstractIntroductionFirst-ray metatarsophalangeal arthrodesis is a classic surgical procedure in the treatment of severe hallux valgus, hallux rigidus, revision surgery, and inflammatory arthritis. The objective of this study was to verify if metatarsophalangeal plate arthrodesis could correct the M1M2 intermetatarsal angle.Material and methodsThis prospective and continuous series (June 2007 to March 2011) included 208 patients (48% severe and/or arthritic hallux valgus, 18% hallux rigidus, 16% rheumatoid forefoot, 13% surgical revision of the first ray, 5% hallux varus), with a mean age of 62.4±9.9 years (range, 19–87 years). All the patients were operated on by a senior surgeon with the same technique: spherical avivement of the joint surfaces using reamers, osteosynthesis with an anatomic plate (Fyxis-Biotech™) in Ti.6Al.4V alloy prebent to 5° with a phalangeal arm to receive an oblique metatarsophalangeal screw in compression, in addition to four 2.7-mm nonlocking dorsal screws. The full-scale preoperative and intraoperative angle measurements were taken on AP and lateral X-rays of the weightbearing foot, as related to the etiology and the severity of the preoperative metatarsus varus (M1M2<15°, M1M2 15–19°, M1M2≥20°). The statistical analysis was done using the StatView software.ResultsThe mean follow-up was 18.6±12.4 months (range, 2–76 months). Nearly all of the arthrodesis patients (97%) achieved bone union, and 5% of the plates were removed. The M1P1angle decreased from 33.8±19.7° (range, −45° to –67°) preoperatively to 13.3±5.3° (range, 0–32°) at the last follow-up, and the M1M2angle from 14.2±5.4°(range, 0–26°) to 6.5±2.3° (range, 0–12°). The preoperative M1M2angle was <15° in 97 patients, 15–19° for 78 patients, and ≥20° for the 33 others; at the last follow-up it was 5.8±2.1° (range, 0–10°), 6.7±2.2° (0–10°), and 8.1±2.4° (3–12°), respectively. No correction of the metatarsus varus was demonstrated in relation to etiology. The M1M2angle was >10° in only two patients (one case of rheumatoid arthritis and one case of severe hallux valgus): 0.9%.DiscussionThese results show that isolated metatarsophalangeal arthrodesis of the first ray can correct metatarsus varus even in substantial deformations in any etiology.Level of proofLevel II cohort study