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.

Standardised radiographs of the weight-bearing foot were analysed in fifty young patients undergoing osteotomy of the first metatarsal for hallux valgus. True metatarsus primus varus was not found more frequently than in a control series. The intermetatarsal angle was significantly greater in affected feet compared with controls. The structural abnormality in hallux valgus in the young is therefore due to a valgus disposition of the second and subsequent metatarsals, rather than varus inclination of the first metatarsal

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. A group of cases is presented in which the os intermetatarseum took the form of an intermetatarsal spur, from which (in members of one family) there arose a tendon-like structure whose distal attachment was to the lateral aspect of the proximal phalanx of the great toe. The suggestion is made that this may represent a lost first plantar interosseous muscle. 2. Another effect of the presence of an os intermetatarseum is the production of metatarsus primus varus by its action as a wedge which spreads apart the bases of the two metatarsal bones. A very small wedge may at times produce considerable deviation (Case 4), and resection of the os can result in satisfactory correction. 3. It is also felt that over-development of extensor hallucis brevis may at times contribute to the formation of hallux valgus