Paper # 148: Microfracture for Focal Full-Thickness Articular Cartilage Defect of Medial Femoral Condyle in Old Aged Osteoarthritis

Abstract

Arthroscopic microfracture for full-thickness articular cartilage defect of medial femoral condyle in old patients produced worse results compared with meniscectomy alone. The purpose of this study was to determine the effectiveness of the microfracture technique for the treatment of focal full-thickness cartilage lesions of the medial femoral condyle in the degenerative arthritis. This study included 40 patients with symptomatic medial meniscus tears, single full thickness cartilage defect on medial femoral condyle and age over 60 years old. Exclusion criteria was Kellgrene-Lawrence grade IV osteoarthritis, varus alignment over 5 degree and lateral compartment cartilage defect. Mean age was 62.8 years (range, 60- 69 years) and there were 36 female and 4 male patients. Only partial medial meniscectomy was done and preserved the subchondral bone integrity without microfracture in 20 patients (group I). Partial medial meniscectomy and microfracture on medial femoral condyle were performed in 20 patients (group II). Follow up period was minimum of 12 months (mean, 16 months; range, 12 to 38 months). Knee function was evaluated with Lysholm score and joint space narrowing was evaluated with anteroposterior plane radiographs taken at postoperative 1 year. Medial meniscus tears were degenerated posterior horn tear in all patients and treated with partial meniscectomy. The size of medial femoral cartilage lesion was 1.7 cm2 (1.0 to 3.2 cm2) and located on weight bearing dome in the range of 10 to 90 degree knee flexion. No difference in the size was found in both groups. In group I, Lysholm scores were 58 preoperatively and improved as 86 at final follow up. In group II, Lysholm scores were improved as 72 from 55. The knee function evaluated with Lysholm score was significantly improved in group I (p= 0.0073). Joint space was decreased in both groups. But in group II, joint space narrowing was progressed faster from 3 months after operation and more severe. In group II, total knee arthroplasty was performed eventually in 3 patients due to severe pain on medial compartment. Arthroscopic microfracture for full-thickness articular cartilage defect of medial femoral condyle in old patients produced worse results compared with meniscectomy alone. One hypothesis is that microfracture can lead to distruction of subchondral bone integrity that was important for sustaining weight loading. Even though the technique of microfracture have advantages like procedure simplicity and low morbidity, the principles of technique and protection from full weight bearing after surgery should be kept for preventing the destruction of subchondral bone integrity.