Aims. The first metatarsal pronation deformity of hallux valgus feet is widely recognized. However, its assessment relies mostly on 3D standing CT scans. Two radiological signs, the first metatarsal round head (RH) and inferior tuberosity position (ITP), have been described, but are seldom used to aid in diagnosis. This study was undertaken to determine the reliability and validity of these two signs for a more convenient and affordable preoperative assessment and postoperative comparison. Methods. A total of 200 feet were randomly selected from the radiograph archives of a foot and ankle clinic. An anteroposterior view of both feet was taken while standing on the same x-ray platform. The intermetatarsal angle (IMA), metatarsophalangeal angle (MPA), medial sesamoid position, RH, and ITP signs were assessed for statistical analysis. Results. There were 127 feet with an IMA > 9°. Both RH and ITP severities correlated significantly with IMA severity. RH and ITP were also significantly associated with each other, and the pronation deformities of these feet are probably related to extrinsic factors. There were also feet with discrepancies between their RH and ITP severities, possibly due to intrinsic torsion of the first metatarsal. Conclusion. Both RH and ITP are reliable first metatarsal pronation signs correlating to the metatarsus primus varus deformity of hallux valgus feet. They should be used more for preoperative and postoperative assessment. Cite this article: Bone Jt Open 2024;5(11):1037–1040

Aims. The purpose of this study is to examine the adductus impact on the second metatarsal by the nonosteotomy nonarthrodesis syndesmosis procedure for the hallux valgus deformity correction, and how it would affect the mechanical function of the forefoot in walking. For correcting the metatarsus primus varus deformity of hallux valgus feet, the syndesmosis procedure binds first metatarsal to the second metatarsal with intermetatarsal cerclage sutures. Methods. We reviewed clinical records of a single surgical practice from its entire 2014 calendar year. In total, 71 patients (121 surgical feet) qualified for the study with a mean follow-up of 20.3 months (SD 6.2). We measured their metatarsus adductus angle with the Sgarlato’s method (SMAA), and the intermetatarsal angle (IMA) and metatarsophalangeal angle (MPA) with Hardy’s mid axial method. We also assessed their American Orthopaedic Foot & Ankle Society (AOFAS) clinical scale score, and photographic and pedobarographic images for clinical function results. Results. SMAA increased from preoperative 15.9° (SD 4.9°) to 17.2° (5.0°) (p < 0.001). IMA and MPA corrected from 14.6° (SD 3.3°) and 31.9° (SD 8.0°) to 7.2° (SD 2.2°) and 18.8° (SD 6.4°) (p < 0.001), respectively. AOFAS score improved from 66.8 (SD 12.0) to 96.1 (SD 8.0) points (p < 0.001). Overall, 98% (119/121) of feet with preoperative plantar calluses had them disappeared or noticeably subsided, and 93% (113/121) of feet demonstrated pedobarographic medialization of forefoot force in walking. We reported all complications. Conclusion. This study, for the first time, reported the previously unknown metatarsus adductus side-effect of the syndesmosis procedure. However, it did not compromise function restoration of the forefoot by evidence of our patients' plantar callus and pedobarographic findings. Level of Clinical Evidence: III. Cite this article: Bone Jt Open 2021;2(3):174–180

Introduction. Osteoarthritis commonly affects the first metatarsophalangeal joint. Stress across this joint has been postulated to increase the incidence of osteoarthritis. Certain foot structures have been associated with a higher incidence of osteoarthritis of the big toe. Utilizing finite elemental analysis, bone stress across the first metatarsophalangeal joint was calculated during mid stance phase of gait and compared in different foot structures. Method. A geometrically accurate three dimensional model of the first metatarsophalangeal joint was created utilising a high resolution 7 tesla MRI and Mimics v14 imaging software. Planus, rectus and cavus feet were simulated by varying the metatarsophalangeal declination angle to 10.1, 20.2 and 30.7 degrees, respectively. A non-manfold computer aided design technique in Mimics v14.2 and finite element method in ANSYS v12 FE were utilised to create the boundary conditions, representing the double support stance phase of gait. Using information from 61 asymptomatic patients with different foot types walking over a Novel emed-x plantar pressure measuring system, plantar loading conditions were applied. Finite elemental analysis was used to predict stress in the first metatarsophalangeal joint in the different foot types. Results. The peak stresses in the distal first metatarsophalangeal joint cartilage were 1.1×10(6) Pa, 6.0×10(5) Pa and 9.7×10(5) Pa for planus, rectus and cavus foot types, respectively. This corresponds to 83.3 percent and 61.6 percent increases in first metatarsophalangeal joint contact stress for the planus and cavus feet relative to the rectus foot. Conclusion. The results suggest there is a higher contact stress of the first metatarsophalangeal joint in patients with pes planus and pes cavus compared to the rectus foot. This may account for the increase risk of first metatarsophalangeal joint osteoarthritis in patients with pes planus. Further work has been initiated utilising this model to measure first metatarsophalangeal joint stress with different hindfoot loading

As it remains unproven that hypermobility of the first tarsometatarsal joint (TMTJ-1) is a significant factor in hallux valgus deformity, the necessity for including arthrodesis of TMTJ-1 as part of a surgical correction of a hallux valgus is questionable. In order to evaluate the role of this arthrodesis on the long-term outcome of hallux valgus surgery, a prospective, blinded, randomised study with long-term follow-up was performed, comparing the Lapidus procedure (which includes such an arthrodesis) with a simple Hohmann distal closing wedge metatarsal osteotomy. The study cohort comprised 101 feet in 87 patients: 50 feet were treated with a Hohmann procedure and 51 with a Lapidus procedure. Hypermobility of TMTJ-1 was assessed pre-operatively by clinical examination. After a mean of 9.25 years (7.25 to 11.42), 91 feet in 77 patients were available for follow-up. There was no difference in clinical or radiological outcome between the two procedures. Also, there was no difference in outcome between the two procedures in the subgroup clinically assessed as hypermobile. This study does not support the theory that a hallux valgus deformity in a patient with a clinically assessed hypermobile TMTJ-1 joint requires fusion of the first tarso-metatarsal joint.

Cite this article: Bone Joint J 2013;95-B:1222–6.