Comparison of Clinical, Radiologic, and Arthroscopic Outcomes Between the Microfracture and Microdrilling Techniques for Articular Cartilage Defects in Medial Opening-Wedge High Tibial Osteotomy

Abstract

Background: Microfracture is the most common procedure for cartilage lesions during medial opening-wedge high tibial osteotomy (MOWHTO), but microdrilling has recently been introduced as an alternative technique.

Purpose: To compare the clinical, radiologic, and arthroscopic outcomes of microfracture and microdrilling during MOWHTO.

Study design: Cohort study; Level of evidence, 3.

Methods: Included were 92 patients who underwent MOWHTO with either microfracture (n = 46) or microdrilling (n = 46), with a minimum follow-up of 24 months. Clinical outcomes included visual analog scale (VAS) for pain, Lysholm score, International Knee Document Committee (IKDC) subjective score, Western Ontario and McMaster Universities index (WOMAC), and objective IKDC grade. Medial femoral condyle (MFC) cartilage repair status was evaluated at 12 months postoperatively using the MOCART (magnetic resonance observation of cartilage repair tissue) 2.0 and the International Cartilage Regeneration & Joint Preservation Society (ICRS) Cartilage Repair Assessment (CRA) grade.

Results: At 6 months postoperatively, the microdrilling group exhibited higher minimal clinically important difference achievement rates than the microfracture group for VAS pain (63.1% vs 41.3%; P = .04), Lysholm (61.2% vs 41.3%; P = .02), and IKDC subjective score (78.3% vs 45.7%; P = .001). At 12 months postoperatively, the microdrilling group exhibited significantly better VAS pain (33.7 ± 17.6 vs 25.7 ± 18.1; P = .03), Lysholm (57.8 ± 12.2 vs 67.9 ± 21.4; P = .007), and IKDC subjective score (52.9 ± 13.5 vs 61.9 ± 10.4; P = .001) compared with the microfracture group, but this difference was not observed at 24 months. WOMAC scores were superior in the microdrilling group at 6 months (32.1 ± 16.7 vs 48.4 ± 16.2; P = .004), 12 months (25.4 ± 15.4 vs 38.1 ± 17.0; P = .03), and 24 months (21.4 ± 13.9 vs 37.3 ± 14.6; P = .02). MFC cartilage repair status was superior in the microdrilling versus microfracture group (ICRS CRA grade, 8.2 ± 2.2 vs 6.7 ± 2.1 [P = .005]; MOCART 2.0 score, 56.3 ± 12.8 vs 49.7 ± 8.9 [P = .02]). At 24 months postoperatively, the microdrilling group had a higher proportion of IKDC A or B grades (84.8% vs 50.0%; P = .001).

Conclusion: Combining MOWHTO with microdrilling for MFC defects resulted in earlier clinical recovery and superior functional outcomes over 24 months postoperatively compared with microfracture and demonstrated excellent cartilage repair on postoperative evaluation.