Osteoarthritis is a major cause of disability in older adults. History of an injury to a joint, particularly the hip or the knee, has been associated with an increased risk for osteoarthritis in retrospective studies. However, the studies may be biased because patients with osteoarthritis may be more likely to recall prior injury. Gelber and associates performed a prospective cohort study of 1,321 adults who were enrolled in their 20s to examine the risk of knee and hip osteoarthritis associated with joint injury occurring during young adult life.

Students who graduated from medical school between 1948 and 1964 were enrolled, and each subject received a thorough history and physical examination. These participants were followed with annual questionnaires to detect incident disease and update risk-factor status over time. Injury was defined as a report of trauma to the knee or hip joint, including internal derangement and fracture. The occurrence of osteoarthritis or degenerative arthritis was defined as a self-report of the presence of one or both of these entities. Only osteoarthritis at the knee and hip were included as outcomes. At the end of follow-up in 1995, all surviving participants who had previously reported osteoarthritis were mailed a more detailed questionnaire with symptom-related questions and a request for any radiologic test results performed on the hips or the knees.

By 1995, the median follow-up was 36 years. Overall, 141 participants had a history of joint injury at the knee, the hip, or both. Sixty-nine participants developed knee osteoarthritis, and 32 developed hip osteoarthritis. The cumulative incidence of knee osteoarthritis by 65 years of age was 13.9 percent among participants with a history of knee injury at baseline and 6.0 percent among those without such a history. In contrast, none of the participants with hip injury before graduation later developed hip osteoarthritis. With regard to participants who sustained a knee or hip injury at any time, including before and after graduation, the cumulative incidence of knee and hip osteoarthritis by 65 years of age was 11.0 percent and 2.2 percent, respectively. The incidence of hip osteoarthritis among participants who did not have hip injury was 0.7 percent.

The authors conclude that adolescents and young adults with traumatic injury to the knee joint, as well as persons with knee and hip injuries occurring during middle age, are at substantially increased risk for osteoarthritis of the same joint later in life. This high-risk group might benefit from primary prevention of osteoarthritis using some combination of joint-stabilizing braces and modification of high-impact exercise to minimize further damage. Proper sports equipment should be used under safe conditions to prevent joint injuries and decrease their long-term complications.