Background/Purpose: Traumatic knee injuries, such as tears and ruptures of the anterior cruciate ligament (ACL) and/or menisci, are associated with osteoarthritis (OA). Surprisingly little is known, however, about the etiology and pathology underlying this association. Large epidemiologic studies of populations with high rates of knee injury are needed to enhance our understanding of the onset and progression of injury-mediated OA. We investigated radiographic OA, symptoms, and patient-reported outcomes in military officers with and without a history of traumatic knee injury.

Methods:

Participants were 439 military officers who either had a history of ACL and/or meniscal injuries (knee injury group) or were injury-free (uninjured group). Participants were recruited from an existing cohort of 6452 military officers originally enrolled between 2004 and 2008 as matriculating cadets at the U.S. Air Force Academy, U.S. Military Academy, or U.S. Naval Academy. The knee injury group (n=167) experienced ACL/meniscal injuries prior to, during, or after their 4-year academy career. The uninjured group (n=272) was site-matched from the same source cohort but had no history of ACL/meniscal injuries. Injury status was established using a self-reported injury history questionnaire, confirmed by clinical record review. Knee OA was assessed using 1) a single-item measure of knee pain, aching, or stiffness in the past 30 days, 2) a patient-reported knee outcome measure (Knee injury and OA Outcome Score [KOOS]; 0 [extreme] – 100 [no problems]), and 3) standardized weight-bearing posteroanterior radiographs of the tibiofemoral joint obtained using a fixed-flexion knee positioning frame. Radiographic knee OA was defined as Kellgren-Lawrence grade ≥2. Knee-injured and non-injured groups were compared using descriptive statistics and prevalence ratios (PR) with 95% confidence intervals (95%CI).

Results: Enrollment was completed on March 31, 2017, and collection of survey and radiographic data is on-going. Currently available data are presented. Among 403 participants with survey data, mean age was 28 years and mean body mass index was 25 kg/m². Per the parent cohort, 40% were women. Mean time from first ACL/meniscal injury to follow-up assessment was 8.6 years. Among participants with available knee radiographic data, 19.0% (16/84) of knee-injured had radiographic knee OA, compared to 0% (0/104) of the uninjured (PR=40, p<0.001). Nearly 38% (51/136) of participants with knee injury reported moderate-severe symptoms vs. 13% (20/156) of the uninjured (PR=2.9, 95%CI: 1.8, 4.7, p<0.001). Among 292 participants with available KOOS data, the knee-injured had clinically-relevant deficits on KOOS symptoms, sports/recreation, and quality of life scales (mean differences: -7.7, -8.1 and -11.0, respectively vs. non-injured, all p<0.001).

Conclusion: Traumatic knee injuries are strongly linked to early-onset knee OA, which greatly impacts quality of life and knee function during physically-vigorous activities. At a mean age of <30 years, young officers with a history of knee trauma experience substantial limitations from OA that impede their military performance.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/relationship-of-traumatic-knee-injuries-to-early-onset-knee-osteoarthritis-in-young-military-officers/