Patient-Reported Activity Levels Correlate With Early Cartilage Degeneration After Anterior Cruciate Ligament Reconstruction

Abstract

Background: The association between activity level after anterior cruciate ligament (ACL) reconstruction (ACLR) and development of posttraumatic osteoarthritis (PTOA) remains unclear. This study investigated the relationship of patient-reported outcomes and progressive cartilage degenerative changes at 3 years after ACLR. Hypothesis: Higher activity levels, as measured by Marx scores, are significantly correlated with early cartilage degeneration after ACLR. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 35 patients (16 women; mean age, 31.0 ± 7.6 years) with isolated ACLR and without pre-existing arthritis were prospectively enrolled. Patients reported Marx activity scores and Knee injury and Osteoarthritis Outcome Score (KOOS) scores and underwent T1ρ magnetic resonance imaging (MRI) preoperatively, 6 months, 1 year, 2 years, and 3 years after ACLR with soft tissue graft (22 autograft). The change in cartilage relaxation times between preoperative and 3-year imaging was used to identify cartilage degeneration, defined as an increase in T1ρ values by 14.3%. Correlation between Marx activity levels, KOOS scores, and T1ρ degeneration was performed with the Spearman rank test. The Fisher exact test was used to test for association between Marx activity score cutoffs and degeneration. The Student t test was used to compare Whole-Organ Magnetic Resonance Imaging Score (WORMS) and T1ρ relaxation times. Significance was defined as P < .05. Results: Sixteen patients (45.7%) showed evidence of cartilage degeneration at 3 years, most frequently in the medial compartment (n = 12; 34%). Higher Marx activity scores at 3 years correlated with cartilage degeneration in the medial femur (rho = 0.34; P = .045), and medial tibia (rho = 0.43; P = .01). A Marx score of 11 or greater at 3 years was significantly associated with medial compartment degeneration ( P = .03), with a positive predictive value of 52.6%. No Marx score cutoff at years 1 or 2 predicted future cartilage degeneration. The KOOS Quality of Life score was inversely correlated with cartilage degeneration (rho = 0.38; P = .02). WORMS did not correlate with degeneration of the medial compartment. Conclusion: Increased activity at 3 years after ACLR was significantly associated with increased risk of medial compartment PTOA. While further research is needed to fully define these relationships, patients may be counseled that return to Marx activity levels of greater than 11 may be associated with a higher risk of medial compartment cartilage degeneration.

Physical Activity Associates with T1rho MRI of Femoral Cartilage Following Anterior Cruciate Ligament Reconstruction

“…Overall daily walking, measured with daily steps, and exercise intensity, measured with time spent in MVPA, should be monitored as individuals rehabilitate after ACLR. In agreement with our results, Friedman et al (24) found higher patient-reported activity levels (Marx activity scores) associated with greater T1rho cartilage compositional degeneration 3 yr after ACLR. Because of the cross-sectional nature of our study, it remains unknown how time spent in MVPA changes throughout ACLR rehabilitation.…”

“…T1rho MRI relaxation times are influenced by joint loading, undergoing transient increases during unloading (22) and decreasing throughout the day due to loading during daily activities (23). Recent literature suggests that higher patient-reported physical activity levels associate with lesser proteoglycan density after ACLR, indicating that higher physical activity levels may be detrimental to cartilage health (24). However, self-reported measures of physical activity are known to overestimate true physical activity levels compared with objective measures (25), and we hypothesize that evaluating objective physical activity outcomes rather than self-reported may yield different results.…”

Long-term Return to Sports After Anterior Cruciate Ligament Injury: Reconstruction vs No Reconstruction—A Comparison of 2 Case Series

“…It may be that modifying their sports reduced the likelihood of further injury and possibly the development of osteoarthritis, which may be higher in patients with reconstruction who are involved in higher-level activities. 14 This very important question will be addressed in a longer-term study.…”

Can we afford to ignore the biology of joint healing and graft incorporation after ACL reconstruction?

“…Li et al 45 evaluated postural stability in ACLR patients and found prolonged T1rho in asymmetric patients persisted up to 2 years where the asymmetric group also reported worse KOOS in all subscores than symmetric ACLR patients and controls. Finally, Friedman et al 46 showed that those achieving a Marx Activity Score of 11 or above at 3 years showed significantly greater T1rho elevations consistent with increasing degeneration over the same time frame. In addition, higher Knee Osteoarthritis and Injury Outcomes Score (KOOS) Quality of Life (QOL) scores correlated with more significant cartilage degeneration.…”