Vol.:(0123456789) 1 3 Knee Surgery, Sports Traumatology, Arthroscopy https://doi.org/10.1007/s00167-020-06146-7 KNEE Mean femoral cartilage thickness is higher in athletes as compared with sedentary individuals Naila Babayeva 1  · Gürhan Dönmez 1  · Levent Özçakar 2  · Şerife Şeyma Torgutalp 1  · Levend Karaçoban 1  · Emre Gedik 3  · Feza Korkusuz 1  · Mahmut Nedim Doral 4 Received: 21 January 2020 / Accepted: 10 July 2020 © European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2020 Abstract Purpose It is unclear how high-intensity physical activity (HIPA) afects the knee joint, specifcally the femoral cartilage (FC). Therefore, the aims of this study were to evaluate FC thickness via ultrasound among elite athletes involved in diferent types of HIPA, and to determine whether there is a correlation between serum cartilage oligomeric matrix protein (sCOMP) and rectus femoris (RF) thickness. Method A total of 132 male individuals participated in this study and were assigned to two groups, the sedentary (n = 43, 23.9 ± 3.7) and athlete groups (n = 89, 22.7 ± 4.6), which did not signifcantly difer in age. The athletes were elite and performed HIPA during sports such as volleyball (n = 20), soccer (n = 21), basketball (n = 28), and weightlifting (n = 20). RF thickness and three (mid-point) measurements were obtained for each knee. The mean FC thickness for each knee was defned as the sum of the medial, lateral condyles, and intercondylar areas. Blood samples for sCOMP analyses were also obtained. Results All the measurements of the FC of both knees were signifcantly higher in the athletes than in the sedentary individu- als (p < 0.001 and p = 0.001). The mean right and left FC values were also higher in the athletes (p < 0.001). Multiple linear regression analysis showed that participation in sporting activities was a signifcant predictor associated with the right and left mean FC thickness (p < 0.001 for both). No signifcant diferences in the sCOMP levels were found between the two groups. Conclusion It was found that the mean FC was higher among athletes than among sedentary individuals. As a result, it is suggested that sports’ participation is an independent factor associated with the right and left mean FC thickness. Level of evidence III. Keywords Femoral cartilage · Thickness · Rectus femoris · sCOMP · Athletes Introduction Mechanical stimulation is considered a regulator of the mus- culoskeletal system and may be the most important external factor responsible for joint homeostasis. It is well known that mechanical stimulation is necessary for the development and maintenance of healthy weight-bearing joints [22, 23, 46]. The ability of tissues to develop and maintain their struc- ture and properties in response to certain types of mechani- cal stimulation is called “functional adaptability” [13]. Although functional adaptation has been clearly observed. in several musculoskeletal system tissues, such as bone and muscle, it is unknown to what extent articular cartilage can withstand repeated loads [6]. The cartilage of the knee joint is a complex tissue, the main functions of which are dissipating stress and pro- viding a surface without friction during movement of the joint [5]. There are conficting fndings regarding whether articular cartilage can tolerate contact peak stresses without incurring damage [6, 7, 47]. According to some studies, an acute bout of running decreases the cartilage thickness of the knee joint [24, 33]. On the other hand, some evidence suggests that prolonged immobilization might be associated * Naila Babayeva nailababayeva@hotmail.com 1 Department of Sports Medicine, Medical Faculty, Hacettepe University, Ankara, Turkey 2 Department of Physical Therapy and Rehabilitation, Medical Faculty, Hacettepe University, Ankara, Turkey 3 Department of Basic Oncology, Cancer Institute, Hacettepe University, Ankara, Turkey 4 Department of Orthopaedics and Traumatology, Ufuk University, Ankara, Turkey