Incidence and Prevalence: Lateral epicondylitis is at least 5 times more common than medial epicondylitis (Mercier). The exact incidence of lateral epicondylitis is difficult to determine, although among the US population it is estimated at 1% to 3% annually (Bryant; Verhaar). Medial epicondylitis accounts for only about 10% to 20% of all epicondylitis (Young). Approximately 15% of patients experience bilateral symptoms.
Epicondylitis is much more common on the lateral side of the elbow (tennis elbow), rather than the medial side Why is lateral epicondylitis 5 times more common than medial epicondylitis?
Otoshi, Kenichi, Misa Takegami, Miho Sekiguchi, Yoshihiro Onishi, Shin Yamazaki, Koji Otani, Hiroaki Shishido, Shunichi Fukuhara, Shinichi Kikuchi, and Shinichi Konno. "Chronic hyperglycemia increases the risk of lateral epicondylitis: the Locomotive Syndrome and Health Outcome in Aizu Cohort Study (LOHAS)." SpringerPlus 4, no. 1 (2015): 1-9.
In this study, the overall prevalence of lateral and medial epicondylitis was 2.5 % and 0.3 %, respectively, which are comparable with previous epidemiologic studies conducted in the general population.
I wonder whether it is due to human activities or some intrinsic differences between lateral and medial epicondyles.