Swimming is a widespread sporting activity generally regarded as an ideal form of exercise, which has little or no impact on the knees. However, overuse or repetitive microtrauma injuries may often affect the knee joint of young competitive swimmers. These early lesions are frequently asymptomatic for a considerable period of time before causing discomfort or joint pain.
The aim of the present study is to use MRI to evaluate the knee joints of asymptomatic young elite swimmers and to compare them with age- and sex-matched controls who do not practice any impact sports regularly.
Cross-sectional case-control study.
MATERIAL AND METHODS:
The authors performed a cross-sectional controlled study to evaluate 54 knees of 27 asymptomatic male adolescents aged 14-15 years, paired by age and weight. Participants were divided in two groups: 13 elite swimmers and 14 control adolescents. The authors performed all the exams using a 0.35-T open-field MRI unit and evaluated by two experienced radiologists blinded to study groups. The images were evaluated to detect the presence or absence of abnormalities.
One or more imaging abnormalities were detected in 18 knees in the group of swimmers (69.2%; p=0.013). The most prevalent findings in the athletes were infrapatellar fat pad edema (53.8%; p=0.049), followed by bone marrow edema (26.9%; p=0.022), edema of prefemoral fat pad (19%; p=0.022) and joint effusion (15.3%; p=0.047).
Significantly more MRI abnormalities were found in the knee joints of asymptomatic adolescent elite swimmers. This high prevalence of positive imaging findings in swimmers may correspond to benign changes or preclinical lesions, which should be evaluated in a follow-up study.
Practical Application: Though swimming is a relatively safe, low impact activity there is still increased risk of knee injury. This study indicates that the repetitive knee motion required for swimming training does lead abnormalities in the joint even in swimmers who do not have knee pain. It is important to realize that these abnormalities increase the likelihood of injury. Recognizing signs of injury early, and referring to a rehabilitation specialist, will help to improve the likelihood of long term success.
Practical Application by: Erin Cameron DPT
In 4th grade, when asked what she wanted to be when she grew up Dr. Erin Cameron, DPT replied “physical therapist,” a rather unconventional response for a child that age. She was a young swimmer with shoulder pain, desperate to return the to sport that she loved so dearly.
The dedication of her physical therapist allowed her to pursue her passion and eventually go on to compete at the collegiate level. While swimming at the University of Michigan she studied to obtain a Bachelor of Science in Movement Science from the School of Kinesiology.
During her collegiate swimming career, she earned the following accolades: two-time CSCAA Honorable Mention Scholar All-American, three-time Big Ten Distinguished Scholar, team captain and the Michigan Leadership Academy Leader of Distinction award.
Erin has dedicated much of her life to the sport of swimming. In addition to competing in the sport for 15 years, she has coached at various elite swim camps and clinics growing her expertise in stroke technique and video critique. She has also served as a volunteer staff member for Division I, II and III swim programs aiding in both coaching and developing exercise programs/educational sessions for upper extremity injury prevention.
Erin received her Doctorate in Physical Therapy from Northwestern University’s Feinberg School of Medicine. During her time in physical therapy school, she developed a special interest in treating patients with a broad range of orthopedic injuries and promoting general health and wellness.
1. Soder RB1, Mizerkowski MD, Petkowicz R, Baldisserotto M. MRI of the knee in asymptomatic adolescent swimmers: a controlled study. Br J Sports Med. 2012 Mar;46(4):268-72. doi: 10.1136/bjsm.2010.083345. Epub 2011 Apr 3.