Background/Purpose: Traumatic knee injuries, such as injuries to the anterior cruciate ligament and menisci, are associated with the early onset and progression of osteoarthritis (OA). However, our understanding of the pathobiologic processes underlying this association is limited. This study examined the precipitating effect of knee ligament and/or meniscal injury on radiographic OA in military officers, a population at high risk of knee injury that also experiences sustained biomechanical loads on the knee joint.

Methods: Radiographic OA was assessed in military officers with a prior history of knee ligament and/or meniscal injuries (injury group) and comparison participants (injury-free group), both selected from a cohort of 6452 military officers enrolled between 2004 and 2009, when participants matriculated at the U.S. Air Force Academy, U.S. Military Academy, or U.S. Naval Academy. The injury group had knee ligament and/or meniscal injuries prior to, during, or after their 4-year academy career (n=115). The injury-free group was site-matched from the same source cohort but had no history of knee ligament and/or meniscal injuries (n=114). Both groups had bilateral knee radiographs taken by radiographic technicians at military treatment facilities who followed a standardized image acquisition protocol using fixed-flexion knee positioning. All images were digitally transferred to a single, highly-experienced musculoskeletal radiologist reader (JBR). Radiographic OA was defined as Kellgren-Lawrence grade 2 or greater. Injury status was established using a standardized questionnaire (first surveys completed between 08/15/15 and 12/13/17; all injuries were verified by clinical record review).

Results: Mean age was 27.7 years (injured: 27.7 years; non-injured 27.7 years) and 38% were women (injured: 34%; non-injured: 42%). Mean weight was 77.4 kg and body mass index was 25.1 kg/m². Mean time from first knee ligament and/or meniscal injury (“knee injury” hereafter) to radiographic assessment was 8.8 years. Officers with a history of knee injury had a greater prevalence of radiographic OA (16.5%) than injury-free officers (0.0%, p<0.001). Officers with knee injury were more likely to have osteophytes (40.9% vs. 7.0%, p<0.001) and joint space narrowing (22.6% vs. 0.9%, p<0.001). Surprisingly, OA prevalence was only weakly related to timing of injury. Specifically, prevalence differences (PDs, injury-free as reference) were similar for those who sustained their first knee injury at high school age (PD=14%, 95%CI: -2%, 31%), collegiate age (PD=20%, 95%CI: 3%, 36%), and post college graduation (PD=13%, 95%CI: -13%, 38%). Similar PDs were obtained from sub-analyses of the unilateral injury subgroup using non-injured limbs (rather than non-injured people) as the reference category.

Conclusion: Nearly 1 out of every 5 officers with knee injury progresses to radiographic OA before age 30. This progression rate may reflect the physically-demanding nature of their occupation. We observed no relationship to timing of injury, suggesting that these “early-progressors” react quickly to the physical insults of knee trauma and surgery.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/association-of-knee-ligament-and-or-meniscal-injury-with-radiographic-knee-osteoarthritis-in-military-officers/