Long-term results after microfracture treatment for full-thickness knee chondral lesions in athletes

Abstract

Purpose: Microfracture is a well-established treatment procedure for chondral defects in high-demand population with good short-term results. The purpose of our study was to evaluate long-term clinical outcome of microfracture treatment in athletes with full-thickness chondral defects.

Methods: Between 1991 and 2001, 170 patients were treated with microfracture for full-thickness knee chondral lesions at our institute and 67 of them were included in this study and prospectively followed up. Sixty-one athletes (91%) were available at final follow-up (average 15.1 years). Average lesion size was 401 ± 27 mm2. Lysholm, Tegner and International Knee Documentation Committee (IKDC) (subjective-objective) scores were utilized pre-operatively and at 2-year, 5-year and final follow-up; Knee injury and Osteoarthritis Outcome Score (KOOS), visual analog scale (VAS) and Marx scores were also collected at final follow-up.

Results: IKDC, Lysholm and Tegner scores increased significantly at 2 years, but gradually deteriorated at long term; however, average scores were significantly above baseline at final follow-up. Seven patients (11%) were considered as failures as they underwent another operation because of reinjury or persistent pain during the first 5 years. Pain and swelling during strenuous activities was reported only in nine patients by the end of 2 years and in 35 patients at final follow-up. Patients with smaller lesions (≤400 mm²) and younger patients (≤30 years) showed significantly better results in KOOS, VAS and Marx scores. Radiographs performed at final follow-up showed evidence of progression of osteoarthritis changes in 40% of the knees, with higher rate in older patients with large or multiple lesions (p < 0.05).

Conclusions: Microfracture when applied in young patients with smaller lesions can offer good clinical results at short- and long-term follow-up; lesion size is more important prognostic factor of outcome than age. Deterioration of the clinical outcome should be expected after 2 and 5 years post-treatment, and degenerative changes are present at long-term follow-up, with higher rate in older athletes with large, multiple lesions.

Level of evidence: IV.