Summary
Cartilage lesions progress significantly between primary and revision ACL reconstruction, based on 20 years of data from 2,845 patients with second-look arthroscopy.
Abstract
Background
Cartilage lesions are a significant concern following ACL reconstruction (ACLR), potentially contributing to long-term joint deterioration and osteoarthritis. However, limited data exist on how cartilage injuries progress over time. This study leverages one of the largest available datasets, using longitudinal second-look data from the Swedish National Knee Ligament Registry (SNKLR) to track cartilage lesion evolution.
Methods
We analyzed all ACL revisions recorded in the SNKLR since its inception, comprising 2,845 patients who underwent both primary and revision ACLR. Cartilage injuries were assessed intraoperatively at both time points and classified by anatomic location, lesion size (<2 cm vs. =2 cm), and severity (ICRS grade). We examined:
1. Prevalence and Distribution: Cartilage lesion frequency at primary vs. revision ACLR.
2. New Cartilage Lesions: Development of new cartilage injuries between primary and revision ACLR.
3. Risk Factors: Identified predictors of cartilage lesions at revision using logistic regression.
Results
At primary ACLR, 533 patients (19%) had at least one cartilage lesion, with a total of 796 lesions (mean 1.5 lesions per knee). At revision ACLR, 1,025 patient (36%), had lesions, totalling 1,936 (mean 1.9 lesions per knee; p < 0.0001).
The medial femoral condyle was the most frequently affected site at both time points, increasing from 374 patients (13%) at primary ACLR to 750 (26%) at revision. The trochlea (OR: 2.11, p = 0.0001) and medial tibia (OR: 1.69, p = 0.0007) showed the greatest increases in prevalence. Severe lesions (ICRS grade 3–4) were most common in the trochlea at revision (32%). Among patients without a cartilage lesion at primary ACLR, 29% developed a new lesion at revision. The medial femoral condyle had the highest incidence of new lesions (20%).
Risk factor analysis identified pre-existing cartilage lesions at primary ACLR as the strongest predictor of revision lesions (OR: 4.18, p < 0.0001). Other significant risk factors included meniscal lesions at revision (OR: 2.12, p < 0.0001), meniscal sutures (OR: 2.38, p < 0.0001), meniscectomy at primary ACLR (OR: 1.50, p = 0.0005), and older age at primary ACLR (OR: 1.03 per year, p < 0.0001).
Conclusion
Cartilage lesions progress significantly between primary and revision ACLR, with both increasing prevalence and severity over time. Pre-existing cartilage lesions, meniscal pathology, and older age are key risk factors. These findings emphasize the need for strategies to slow cartilage deterioration following ACL injury.