Incidence and Risk Factors for Chronic Anterior Knee Pain

Chronic anterior knee pain is a common clinical entity, more so in the active individual. The incidence and risk factors, however remain unexplored. We investigated the correlation of demographic and occupational risk factors as well as the incidence of chronic anterior knee pain in an active military population. We performed a retrospective review of all U. S. Military active duty service members with the diagnosis of chondromalacia patellae, representative of the clinical syndrome of chronic anterior knee pain, between 2006 and 2012 using the Defense Medical Epidemiology Database. The demographic and occupation risk factors were categorized and the subgroup and overall incidence rates were determined via multivariable analysis. A total of 42,040 cases of chondromalacia patellae were identified in an at-risk population of 9,723,449, corresponding to an incidence rate of 4.32 cases per 1,000 person-years. Increasing chronological age, female sex, Black race, junior enlisted rank, and primary ground forces (Marines and Army) significantly correlated with an increased risk for chronic anterior knee pain. This study is the first report of incidence and risk factors for chondromalacia patellae in a large athletic population. We determined that sex, age, race, branch of service, and rank all correlated with the incidence of chondromalacia patellae in an active population.