The effects of running on lower limb cartilages
J.-F. Esculier Osteoarthritis and Cartilage VOLUME 25, SUPPLEMENT 1, S145, APRIL 01, 2017
Purpose: While several reviews have examined the long-term association between running and osteoarthritis, no review has explored the effects of running specifically on lower limb cartilages. Therefore, the objective of this systematic review is to summarize the literature with regards to the prospective effects of running on hip, knee and ankle cartilage structure and physiology.
Methods: Database searches were performed in Pubmed, Embase, CINAHL, SportDiscus, Web of Science and the Cochrane Central Registry of Controlled Trials up to July 1, 2016. The strategy included a combination of the following keywords: (lower limb, hip, coxofemoral, knee, tibiofemoral, patellofemoral, ankle, foot) AND (running, runner) AND (cartilage, osteoarthritis, magnetic resonance imaging [MRI]). Hand searches of retrieved articles reference lists were also conducted. Full-length peer-reviewed papers investigating the prospective effects of running on lower limb cartilages in humans using MRI were included. Studies could either evaluate the effects of a single bout of running or repeated exposure. Two raters independently evaluated the methodological quality of each included article using a structured critical appraisal tool. The effects of running on joint imaging variables were classified as short term if MRI was performed within 24 hours after a single bout of running, medium-term if between 24 hours and 2 weeks after a single run, and long-term when more than 2 weeks or when studying the effects of multiple running trainings. Outcomes included cartilage thickness, volume, T2-T2* relaxation time, glycosaminoglycans (GAG) content and cartilage lesions.
Results: A total of 2420 titles were retrieved and analyzed for appropriateness based on inclusion and exclusion criteria. Twenty-four studies were included in analyses: 23 articles studied the effects of running on knee cartilages, while only 1 investigated hip and ankle cartilages. Thirteen studies were rated as high quality, 8 as moderate quality and 3 as low quality. Short-term effects.
Overall, there is strong evidence that a bout of running decreases femoral, tibial and patellar cartilage thickness and volume. Moderate evidence suggests that T2 relaxation time is decreased at the femoral and tibial cartilages immediately after a short bout of running; after a marathon, however, very limited evidence indicates increased T2*. Based on limited evidence, running seems to have no negative effects on pre-existing knee cartilage lesions.
Medium-term effects. There is moderate and very limited evidence that running has no detrimental effects on the number or grade of cartilage lesions at the knee and hip, respectively.
Long-term effects. Very limited evidence indicates that long-term running has no effect on knee cartilage thickness, but there is conflicting evidence regarding volume. As for T2 relaxation time, limited evidence supports increased values up to 3 months post-marathon. There is very limited evidence that repeated exposure to running through a start-to-run program causes an increase in GAG content at the tibiofemoral cartilage. Moderate evidence indicates that running has no detrimental effects on the number or grade of lesions in the knee in the long term. At the ankle joint, limited evidence suggests that an ultra-endurance running event has no effect on cartilage thickness. Limited evidence also suggests increased T2* relaxation times during the first half of the event, followed by a decrease indicative of partial regeneration.
Conclusions: This systematic review highlights the disparity between the reported effects of running on lower limb cartilages depending on study design. According to current evidence, cartilages may present short-term decreases in thickness, volume and relaxation time secondary to temporary loss of fluid following repeated compressions. However, cartilages may well tolerate mechanical loading sustained during running and adapt to repeated exposure.