Microfracture treatment of single or multiple articular cartilage defects of the knee: a 5-year median follow-up of 110 patients

We compared the results of microfracture in single versus multiple symptomatic articular cartilage defects in the knee in 110 patients with a median age of 38 years (range 15–60). Cases of reoperation of the cartilage defect were classified as failures. Clinical outcome in non-failures was evaluated by the Lysholm score and grading of knee pain and function of the knee by the use of patient-administered visual analog scales (VAS; 0–100). Data were prospectively collected before the operation and at the 2- to 9-year follow-up. The single lesion or the largest of multiple lesions were located on the medial femoral condyle (n = 62), trochlea (n = 18), lateral tibia (n = 11), patella (n = 10) or lateral femoral condyle (n = 9). We treated one (n = 76), two (n = 27) or three (n = 7) lesions with a median total area of 4 cm² (range 1–15). A total of 24 failures (22%) were registered—18% in the single-defect subgroup and 29% in the multiple-defects subgroup. In the remaining group of patients (n = 86), the mean Lysholm score, mean pain-score (0 = no pain; 100 = worst possible pain) and mean function-score (0 = useless; 100 = full function) improved from 51, 52 and 41, respectively, to 71 (P < 0.001), 30 (P < 0.001) and 69 (P < 0.001) at the follow-up. The pain-score was significant lower (P = 0.042), and the function-score significantly higher (P = 0.001) in the group of patients with a single lesion compared to the group with 2 or 3 lesions. The Lysholm score did not differ significantly between the two subgroups (P = 0.06).