Long-Term Knee Health in Adults with a History of Adolescent Osgood–Schlatter: A National Cohort Study of Patients in Secondary Care in Denmark 1977–2020

Background: Osgood–Schlatter has, until recently, been suggested to be a benign condition, affecting adolescents in terms of knee pain and decreased sports participation during growth, with no long-term consequences seen later in adulthood. Objectives: The objectives of this study were to describe the long-term knee health in adults with a history of Osgood–Schlatter, compare these findings with healthy population estimates, and investigate if explanatory variables are associated with current knee health. Methods: The Danish Patient Registry identified patients ≥ 18 years diagnosed with adolescent Osgood–Schlatter in hospitals during 1977–2020. All cases participated in a survey about knee-related health and comorbidities. Existing literature was sourced for the healthy population estimates for comparisons. Explanatory variables were recalled Osgood–Schlatter duration, pain levels, restrictions, and current tibial tubercle prominence. Results: Of 1281 identified patients, 400 responded. Most reported having a current bony prominence of the tibial tubercle (85%) and sustained pain/problems from the same area (73%). Compared with healthy population estimates, Osgood–Schlatter cases scored lower on the Knee Injury and Osteoarthritis Outcome Score on all subscales (p < 0.05), particularly for “sport/rec” and “quality of life” (Cohen’s d > 0.8). Similarly, cases exhibited a large risk of “jumper’s knee” (odds ratio: 70.4 [95% confidence intervals, CI: 32.9; 155.0], p < 0.0001). Symptom duration and pain levels were negatively associated with several outcomes (p < 0.05). Conclusions: Adults with a history of Osgood–Schlatter have significantly worse long-term knee health than what is observed from healthy population estimates. Recalled longer symptom duration and higher pain levels were associated with worse current knee health. This information should potentially guide management to maintain knee health over time, as the condition is not always as benign and self-limiting as previously thought. Registration: NCT04313621.