Summary

Microfracture treatment for cartilage lesions of the medial femoral condyle during ACLR is associated with the worst patient-reported outcomes, emphasizing the need for careful treatment selection.

Abstract

Background

Cartilage lesions of the medial femoral condyle (MFC) are common during primary ACL reconstruction (ACLR) and significantly influence patient-reported outcomes. While several treatment options are available for addressing cartilage lesions, their specific impact on subjective knee function remains insufficiently understood.

Purpose

To investigate the influence of different cartilage treatment strategies during primary ACLR on the Knee injury and Osteoarthritis Outcome Score (KOOS) two years postoperatively.

Methods

Patients with MFC cartilage lesions who underwent primary ACLR between 2008 and 2022 were retrospectively studied using data from the Swedish National Knee Ligament Registry. Cartilage lesions were treated with debridement, microfracture, other methods (osteochondral autograft transplantation, autologous chondrocyte implantation, or unspecified treatments), or non-surgically. Thresholds for minimal important change (MIC ≥9), patient acceptable symptom state (PASS ≥79), and treatment failure (TF ≤42) of the KOOS4 (mean score of the KOOS Pain, Symptoms, Sports/Rec, and QoL subscales) were applied.

Multivariable logistic regressions were performed to assess variables influencing MIC, PASS, and TF of the KOOS4. These were adjusted for the type of cartilage treatment performed, cartilage lesion characteristics (area ≥2 cm2, International Cartilage Repair Society (ICRS) grade 3-4, and isolated/multifocal extent), patient characteristics (age, sex, pivoting sports injury, concomitant meniscal tears, preoperative KOOS4), ACL graft type, time to surgery, and surgeon and clinic volume. Results were presented as odds ratios (OR) with 95% confidence intervals (CI).

Results

The study included 8,006 patients with MFC cartilage lesions at ACLR. Debridement was performed in 17.4% of cases, microfracture in 7.6%, other treatments in 1.1% and non-surgical treatment in 73.9%, p<0.001. Patients receiving microfracture and non-surgical treatment were younger (median age 32 and 31 years) than those having debridement and other treatments (median age 35 and 40 years), p<0.001. Larger lesions (≥2 cm²) were more common in patients receiving other treatment methods (52.9% vs. 35.8-39.3%), p=0.001. The percentage of patients with ICRS grade 3-4 lesions were the highest in the microfracture group (91.7% vs. 10.5-60.9%), and isolated chondral injuries were most common in patients treated with microfracture (74.1%) or debridement (67.2%), all p<0.001.

KOOS was completed by 48.6% of patients at two years, with no significant differences in rates between treatment groups. Fewer patients in the microfracture group achieved PASS (22.9% vs. 41.9-42.3%, p<0.001). Although not statistically significant, patients receiving microfracture had the lowest percentage of achieving MIC (63.3% vs. 64.7-73.8%, p=0.059) and the highest percentage experiencing TF (15.4% vs. 10.9-14.0%, p=0.175). Adjusted logistic regression analyses showed that patients treated with microfracture had significantly lower odds of achieving PASS (OR 0.36, 95%CI 0.23-0.57, p<0.001) and MIC (OR 0.55, 95%CI 0.36-0.85, p=0.007) compared to those having debridement. Treatment methods did not influence TF. Moreover, patient age, pivoting sports injuries, meniscal tears, isolated cartilage lesions, time to surgery and preoperative KOOS4 influenced the odds of MIC, PASS and TF.

Conclusion

Microfracture treatment for MFC cartilage lesions was associated with the worst patient outcomes in terms of reduced satisfaction and decreased improvement. These findings suggest the need for careful consideration when selecting treatment strategies for cartilage lesions during ACLR.