DWYER OSTEOTOMY FOR THE TREATMENT OF CHRONIC ANKLE INSTABILITY WITHOUT OVERT LAXITY: 15 CASES

Abstract

Purpose: Chronic ankle instability is generally related to lateral laxity of the tibiotalar joint. Stress x-rays may however be negative. Varus of the hindfoot is another possibility. In such cases, it would be logical to propose Dwyer valgus osteotomy of the calcaneum. The objective of this work was to review patients who underwent Dwyer osteotomy from 1992 to 2000.

Material and methods: The series included fifteen patients, nine men and six women, who complained of chronic ankle instability with no evidence of laxity. All presented a varus hindfoot (mean 5°, range 3–10°). Thirteen patients practiced sports, including eight at the competition level. Sixty percent had experienced instability accidents during sports activities. Associated lesions were fissures of the fibular tendons (n=2), osteochondral lesion of the talar dome (n=1), Haglund disease (n=1) and stage II pes cavus (n=2). Lateral closed Dwyer osteotomy was performed in all cases, generally with fixed with two screws in a 2-hole 1/3 plate. Associated procedures were: lateral ligamentoplasty (n=1), osteotomy to raise M1 (n=2), regularisation of an osteochondral lesion of the talar dome (n=1), Zadek osteotomy (n=1) and anterior arthrolysis (n=1). The same surgeon reviewed the patients clinically and radiologically, independent of the operator.

Results: Mean follow-up was 3.5 years (range 1–9, SD 2.5). There were no complications except one case of cutaneous necrosis in the patient who had simultaneous osteotomy and ligamentoplasty. Instability resolved in all patients. Ten patients experienced minor episodic pain (50% during sports activities). Eleven patients (70%) resumed their sports activities within eight months (3–36) and 33% at their former level. The mean Kitaoka score was 92 (85–100) and 80% of the patients were satisfied or very satisfied.

Conclusion: Dwyer osteotomy provides quite satisfactory results for patients with chronic ankle instability without evidence of laxity and hindfoot varus. When a complementary ligamentoplasty appears to be necessary, it is preferable to wait for a second operation in order to avoid the risk of cutaneous necrosis.