Metatarsus primus varus deformity correction is one of the main objectives in hallux valgus surgery. A ‘syndesmosis’ procedure may be used to correct hallux valgus. An osteotomy is not involved. The aim is to realign the first metatarsal using soft tissues and a cerclage wire around the necks of the first and second metatarsals. We have retrospectively assessed 27 patients (54 feet) using the American Orthopaedic Foot and Ankle Society (AOFAS) score, radiographs and measurements of the plantar pressures after bilateral syndesmosis procedures. There were 26 women. The mean age of the patients was 46 years (18 to 70) and the mean follow-up was 26.4 months (24 to 33.4). Matched-pair comparisons of the AOFAS scores, the radiological parameters and the plantar pressure measurements were conducted pre- and post-operatively, with the mean of the left and right feet. The mean AOFAS score improved from 62.8 to 94.4 points (p < 0.001). Significant differences were found on all radiological parameters (p < 0.001). The mean hallux valgus and first intermetatarsal angles were reduced from 33.2° (24.3° to 49.8°) to 19.1° (10.1° to 45.3°) (p < 0.001) and from 15.0° (10.2° to 18.6°) to 7.2° (4.2° to 11.4°) (p < 0.001) respectively. The mean medial sesamoid position changed from 6.3(4.5 to 7) to 3.6 (2 to 7) (p < 0.001) according to the Hardy’s scale (0 to 7). The mean maximum force and the force–time integral under the hallux region were significantly increased by 71.1% (p = 0.001), (20.57 (0.08 to 58.3) to 35.20 (6.63 to 67.48)) and 73.4% (p = 0.014), (4.44 (0.00 to 22.74) to 7.70 (1.28 to 19.23)) respectively. The occurrence of the maximum force under the hallux region was delayed by 11% (p = 0.02), (87.3% stance (36.3% to 100%) to 96.8% stance (93.0% to 100%)). The force data reflected the restoration of the function of the hallux. Three patients suffered a stress fracture of the neck of the second metatarsal. The short-term results of this surgical procedure for the treatment of hallux valgus are satisfactory. Cite this article: Bone Joint J 2014;96-B:502–7

A survey of 6000 schoolchildren discovered 36 cases of unilateral and 60 cases of bilateral hallux valgus, defined as a metatarsophalangeal angle of more than 14.5 degrees, measured on standing radiographs. Metatarsus primus varus was found not only in the early stages of hallux valgus but in the unaffected feet of children with unilateral hallux valgus. Adduction of the first metatarsal is not due to differential growth of the cortices of the first metatarsal nor is it a consequence of malalignment of the metatarsocuneiform joint. The intermetatarsal angle did not correlate with the angle of metatarsus adductus nor with the intercuneiform angle

The contributions made by metatarsus primus varus, medial subluxation of the navicular, and angulation of the neck of the talus to the residual deformity in treated club feet were assessed from radiographs. Their relation to the appearance of the feet, to the age of the patient, to the results of operations, and to the age at the time of the first operation were investigated. Lateral rotation of the ankle and flattening of the talus were also studied. Medial subluxation of the navicular was found to be the most important factor influencing both the appearance of the feet and the lateral rotation of the ankle. Relocation of the talonavicular joint correlated with the success of operative treatment; and the timing of the primary operation determined the degree of relocation which could be achieved. Metatarsus primus varus and angulation of the talus were of little importance. Increased emphasis is given to the need for early relocation of the talonavicular joint

1. Pathological hallux valgus may be differentiated from an increase in the normal valgus alignment of the great toe by the relationship to each other of the articular surfaces of the first metatarso-phalangeal joint; these are congruous in the normal joint, but displaced on each other in the pathological. 2. The earliest change is lateral deviation of the proximal phalanx on the metatarsal head, which may progress rapidly to subluxation. 3. Subluxation is an early change in a high proportion of cases, and is frequently present when the patient is first seen in adolescence. 4. Once subluxation has occurred progression of the deformity is likely. 5. Metatarsus primus varus and hallux valgus increase pari passu. There is not enough evidence to be certain which of these is the primary change, but such as there is suggests that lateral deviation of the great toe occurs first, and increase in the intermetatarsal angle is secondary to this. 6. It is suggested that hallux valgus should be regarded primarily and fundamentally as a subluxation, or tendency to subluxation, of the first metatarso-phalangeal joint