Prevalence of Chondral Defects in Athletes' Knees: A Systematic Review

David C. Flanigan; Joshua D. Harris; Thai Q. Trinh; Robert A. Siston; Robert H. Brophy


Med Sci Sports Exerc. 2010;42(10):1795-1801. 

In This Article

Abstract and Introduction


Purpose: To determine the prevalence of full-thickness focal chondral defects in the athlete's knee.
Methods: We conducted a systematic review of multiple databases, evaluating studies of the prevalence of articular cartilage defects in athletes. Because of the heterogeneity of data, a meta-analysis could not be performed.
Results: Eleven studies were identified for inclusion (931 subjects). All studies were level 4 evidence. Defects were diagnosed via magnetic resonance imaging, arthroscopy, or both. Forty percent of athletes were professionals (NBA and NFL). The overall prevalence of full-thickness focal chondral defects in athletes was 36% (range = 2.4%–75% between all studies). Fourteen percent of athletes were asymptomatic at the time of diagnosis. Patellofemoral defects (37%) were more common than femoral condyle (35%) and tibial plateau defects (25%). Medial condyle defects were more common than lateral (68% vs 32%), and patella defects were more common than trochlea (64% vs 36%). Meniscal tear (47%) was the most common concomitant knee pathological finding, followed by anterior cruciate ligament tear (30%) and then medial collateral ligament or lateral collateral ligament tear (14%).
Conclusions: Full-thickness focal chondral defects in the knee are more common in athletes than among the general population. More than one-half of asymptomatic athletes have a full-thickness defect. Further study is needed to define more precisely the prevalence of these lesions in this population.


Articular cartilage defects of the knee demonstrate limited regenerative potential in response to injury and, therefore, have been implicated as a potential risk factor in the development of early-onset osteoarthritis.[1,13,41] Chondral defects are seen in 34%–62% of knee arthroscopies,[2,12,18,52] while full-thickness focal lesions of with an area of at least 1–2 cm2 are seen in 4.2%–6.2% (range of prevalence among referenced studies) of all arthroscopies[2,12,18,52] in patients younger than 40 yr. These studies document the prevalence of chondral defects in all patients within the general population, athletes and nonathletes alike, of any age requiring knee arthroscopy for any reason. Younger patients with large, isolated, full-thickness defects represent those most amenable to cartilage repair or restoration with marrow stimulation techniques, osteochondral autograft transfer system (OATS/mosaicplasty), osteochondral allograft, or cell-based therapy with autologous chondrocyte implantation (ACI).[10,35]

The natural history of the isolated chondral defect and to what degree the isolated defect may become symptomatic is not completely understood.[8] The presence of concomitant injuries, whether acute or chronic, further influences management of these lesions. Insufficiency of the anterior cruciate ligament (ACL),[19,45,51] deficiency of the menisci, and malalignment of both the patellofemoral and tibiofemoral compartments must be addressed during surgery.[10,53] Intra-articular knee injuries are known to occur more frequently in an athletic population and may lead to degenerative changes in the knee.[26] Compared with the general population, athletes place a higher demand on the knee and, as a result, are 12 times more likely to develop osteoarthritis.[13,41] Epidemiologic data suggest that athletes subjected to both acute contact trauma and repetitive joint loading during pivoting and twisting are more likely to show signs of joint degeneration.[13,41]

A recent systematic review of microfracture concluded that early treatment of chondral defects with microfracture was associated with positive clinical and histologic outcomes.[36] Another systematic review[17b] reported that early treatment of defects with either ACI or microfracture was associated with positive clinical outcomes and earlier return to sport. Therefore, early diagnosis and treatment of chondral defects in the knee of the athlete may facilitate a quicker return to sport after injury and decrease the risk of developing osteoarthritis in the future.[35] Although the prevalence of chondral defects in the general population, athletes and nonathletes together, has been well documented, the prevalence of chondral defects in an exclusively athletic population is currently unknown. The purpose of this systematic review was to report the prevalence of full-thickness chondral defects in athletes using the currently available evidence. We hypothesize that the prevalence of articular cartilage lesions in the athlete is higher than published standards for the general population.


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