Recovery of the menisci and articular cartilage of runners after cessation of exercise: Additional aspects of in vivo investigation based on 3-dimensional magnetic resonance imaging

Background: It is still unclear whether long-distance running has a deleterious effect on joint health; therefore, this study was undertaken to examine the rate of recovery from alterations occurring at the knee joint in marathon runners due to loading. Hypothesis: Tibial, patellar, and meniscal cartilaginous volumes are able to recover adequately from changes due to repeated loading immediately after cessation. Study Design: Controlled laboratory study. Methods: Twenty knees of male athletes were studied (mean age, 38 ± 14 years). The participants ran 20 km around a predetermined and precisely measured course. Cartilaginous volume was measured by magnetic resonance imaging before the run (60-min rest before exercise), immediately after the run (3-min delay), and after a recovery period of 1 hour. Results: After the 20-km run, there was a significant transient decrease in cartilage volume. After 1 hour of rest, no significant reduction of cartilage volume was measured for the patella (-2.1%), the tibia (-1.2%), the lateral meniscus (-3.2%), or the medial meniscus (-5.9%). However, the values recorded for the menisci were borderline, which indicates that recovery of meniscus volume lags behind that of articular cartilage. Conclusion: Our data indicate a clear tendency toward rapid recovery of the cartilaginous and meniscal volumes at the knee. The results of this study lead to the assumption that the cartilage and the menisci are well able to adapt to the loads caused by running. Investigation of more subtle changes would require more specific magnetic resonance imaging techniques, including T2-weighted mapping and T1-weighted rho sequences, to assess cartilage biochemistry. Clinical Relevance: The articular structures were investigated on a general magnetic resonance imaging level and were found to recover rapidly so that exercise could be continued after a short time without reservation.