Abstract
Objectives
Osteochondral ankle defects (OCDs) mainly occur in a young, active population. In 63% of cases the defect is located on the medial talar dome. Arthroscopic debridement and microfracture is considered the primary treatment for defects up to 15 mm. To treat patients with a secondary OCD of the medial talar dome, a 15-mm diameter metal implant (HemiCAP ®) was developed. The set of 15 offset sizes was designed to correspond with the anatomy of various talar dome curvatures. Recently, two independent biomechanical cadaver studies were published, providing rationale for clinical use. The present study was undertaken to evaluate the clinical effectiveness and safety of the metal implantation technique for osteochondral lesions of the medial talar dome in a prospective study.
Material and methods
Since October 2007, twenty patients have been treated with the implant. Four patients who did not meet the inclusion criteria and four patients who had less than one-year follow-up at the time of writing were left out of this analysis. Twelve patients are reported with one year (n=8) or two years (n=4) follow-up. All patients had had one or two earlier operations without success. On preoperative CT-scanning, the mean lesion size was 16 × 11 (range, 9–26 × 8–14) mm. Outcome measures were: Numeric Rating Scale pain (NRS) at rest and when walking, Foot Ankle Outcome Score (FAOS), American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot score, and clinical and radiographic complications. Data are presented as median and range. The Wilcoxon signed ranks test was used to calculate p-values.
Results
All patients recovered well from surgery. The NRS at rest improved from 3 (0–7) preoperatively, to 0.5 (0–4) after 1 year and 1 (0–1) after 2 years follow-up (p < 0.05). The NRS when walking was 6.5 (4–8) preoperatively, improving to 1.5 (0–5) at 1 year and 1 (0–2) at 2 years follow-up (p < 0.05). The five subscales of the FAOS improved from 14–64 preoperatively, to 53–91 after 1 year and 63–100 after 2 years (p < 0.05). The AOFAS improved from 70 (42–75) before surgery to 86 (58–100) at 1 year, and 89 (82–90) at 2 years follow-up (p < 0.05). There were no clinical or radiographic complications.
Conclusion
The metallic implantation technique appears to be a promising treatment for secondary OCDs of the talus, but more patients and longer follow-up are necessary to draw firm conclusions.
