Is good muscle function a protective factor for early signs of knee osteoarthritis after anterior cruciate ligament reconstruction? The SHIELD cohort study protocol

Anna Cronström,May Arna Risberg,Martin Englund,Carl Johan Tiderius,Patrik Önnerfjord,André Struglics,Jonas Svensson,Pernilla Peterson,Sven Månsson,Eva Ageberg

doi:10.1016/j.ocarto.2020.100102

Abstract

Knee injury history and increased joint load, respectively, are major risk factors for the development of knee osteoarthritis (OA). Lower extremity muscle function, such as knee muscle strength, influence joint load and may be important for the onset of knee OA. However, the role of muscle function as a possible modifiable protective mechanism for the development of OA after anterior cruciate ligament reconstruction (ACLR) is not clear. In this prospective cohort study, 100 patients (50% women, 18-35 years) with ACLR will be recruited from Skåne University Hospital, Sweden and Oslo University Hospital, Norway. They will be assessed with a comprehensive test battery of muscle function including muscle strength, muscle activation, hop performance, and postural orientation as well as patient-reported outcomes, one year (baseline) and three years (follow-up) after ACLR. Primary predictor will be knee extension strength, primary outcome will be patient-reported knee pain (Knee injury and Osteoarthritis Outcome Score, subscale pain) and secondary outcomes include compositional MRI (T2 mapping) and turnover of cartilage and bone biomarkers. Separate linear regression model will be used to elucidate the influence of each baseline muscle function variable on the outcomes at follow-up, adjusted for baseline values. Twenty non-injured individuals will also be assessed with MRI. This study is approved by The Regional Ethical Review Board in Lund (Sweden) and Oslo (Norway). This study may have important clinical implications for using muscle function to screen for risk of early-onset knee OA and for optimizing exercise therapy after knee injury.

Highlights

An anterior cruciate ligament (ACL) injury is commonly associated with long-term functional limitations [1,2,3,4]
A recent systematic review and meta-analysis found that a previous ACL injury was associated with a four to six-fold increased risk of developing knee OA two to 22 years post knee injury [5]
Our study will be the first to investigate the role of different measures of muscle function as possible protective factors for possible markers of early OA development including patientreported pain, Magnetic resonance imaging (MRI), and biomarkers in patients with anterior cruciate ligament reconstruction (ACLR)

Summary

Introduction

An anterior cruciate ligament (ACL) injury is commonly associated with long-term functional limitations [1,2,3,4]. It is well established that a history of knee injury is a major risk factor for the development of knee osteoarthritis (OA). A recent systematic review and meta-analysis found that a previous ACL injury was associated with a four to six-fold increased risk of developing knee OA two to 22 years post knee injury [5]. Follow-up of approximately 5–10 years is required to detect radiographic features indicative of OA such as joint space narrowing and osteophytes, i.e., features found relatively late in the disease process [6], indicating that radiography is not useful for early detection of OA [7,8].

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Discussion

Conclusion