Proximal first metatarsal opening wedge osteotomy with a low profile plate.

BACKGROUND: Many surgical procedures have been described for the correction of metatarsus primus varus associated with hallux valgus deformity. The purpose of this study was to present the results of the proximal metatarsal opening wedge (PMOW) osteotomy using the Arthrex LPS(R) first metatarsal system.

MATERIALS AND METHODS: Eighty-four patients (90 feet) underwent PMOW osteotomy with distal bunionectomy. There were 78 patients (93%) and 84 (93%) feet available for followup. Mean followup was 2.4 (range, 2.0 to 3.2) years from the time of the index surgery. Pre- and postoperative clinical examination, level of activity, patient derived subjective satisfaction score, radiographic measurements, and visual analogue scale (VAS) score for pain were obtained and evaluated retrospectively.

RESULTS: The mean preoperative VAS score was 5.9 (+/- 2.2), compared with a mean postoperative score of 0.5 (+/- 0.8). The mean 1-2 IMA preoperatively was 14.5 (+/-3.3) degrees, compared with postoperative measurements of 4.6 (+/- 2.8) degrees. The mean hallux valgus angle (HVA) improved from a mean of 30 (range, 22 to 64) degrees preoperatively to 10 (range, -15 to +18) degrees. The mean time to radiographic union was 5.9 (range, 4 to 14) weeks. There was one nonunion, one delayed union, mild hallux varus in two patients, severe hallux varus in two patients, recurrent hallux valgus in three patients (including the nonunion) and no instances of plate failure there was no significant difference in mean preoperative (74.8 degrees +/- 11) compared to postoperative (67.9 degrees +/- 10) total MTP joint range of motion. Ninety percent of patients reported good to excellent subjective results after the index surgery.

CONCLUSION: We believe PMOW osteotomy was near ideal in terms of reliable, predictable correction and healing. Length of the first metatarsal was maintained and patients ambulated safely in a CAM walking boot immediately after surgery. We believe a first web space release may result in hallux varus and increased distal metatarsal articular angle (DMAA) was associated with hallux valgus recurrence.