Protective Role of Muscle Function for Early Features of Knee Osteoarthritis After Anterior Cruciate Ligament Injury
Condition: Knee Osteoarthritis; Anterior Cruciate Ligament Injury; Osteoarthritis, Knee; Muscle Weakness
MeSH terms: Osteoarthritis; Osteoarthritis, Knee; Muscle Weakness; Wounds and Injuries; Anterior Cruciate Ligament Injuries
Study type: Observational

Summary: 
      In this longitudinal prospective cohort study including young people with anterior cruciate
      ligament reconstruction (ACLR), the aims are to 1) study the association between different
      measures of muscle function and early future of knee osteoarthritis (OA) assessed as
      patient-reported pain, 2) explore potential associations between muscle function and features
      indicative of early radiographic OA measured with MRI, and early detection of OA in biomarker
      profiles, respectively, 3) monitor the patients' functional status, and early OA development
      over time and 4) investigate the prevalence of early knee OA in individuals 1 and 3 years
      post ACLR, respectively, compared to non-injured controls.The main hypothesis is that knee
      extensor weakness predicts future symptomatic OA of the knee (KOOS pain).
    

Detailed description: 
      This is a longitudinal, prospective, cohort study. The reporting will adhere to the STROBE
      guidelines. Approximately 100 patients 12 months (range 10 - 16 months) after anterior
      cruciate ligament reconstruction (ACLR) will be recruited from Skåne University Hospital,
      Sweden and Ullevål Hospital, Oslo, Norway. The majority of the patients (approx. 80 %) will
      be recruited in Sweden. As a sample of convenience, 20 age- and sex-matched non-knee injured
      individuals will be recruited among students in Lund, Sweden.

      A research coordinator at each site will determine eligibility for the study, based on
      pre-specified inclusion and exclusion criteria. Patients will be provided with written and
      oral information about the study. Patients who accept to participate will be assessed with
      various measures of muscle function, patient-reported outcomes, MRI, and blood samples for
      biomarker analyses, at baseline (1 year after ACLR) and 2 years later (3 years after ACLR).

      For descriptive purposes, the mean difference (95% CI), or median (quartiles), between
      baseline and follow-up assessments will be used as appropriate. Separate linear regression
      model will be used to elucidate the influence of change in each muscle function variable on
      change in primary, secondary and exploratory outcomes (biomarkers), adjusted for baseline
      values. Separate linear regression models will also be used to elucidate the influence of
      demographic factors on change in muscle function, self-reported outcomes, and early OA.
      Assuming a clinically relevant correlation of 0.30 between knee extension strength and
      self-reported pain, 84 patients are needed with 80% power at the 5% significance level. Based
      on this calculation, 100 patients will be included, including an approximate drop-out of 15%.
      For explorative purposes, an analysis of covariance (ANCOVA) will be used to investigate
      differences in the presence of early knee OA between the 100 patients with ACLR and twenty
      sex and age matched non-injured individuals, adjusting for activity level.
    

Intervention name(s): Measures of muscle function
Intervention type(s): Other
Intervention description(s): The participants will be assessed with various measures of muscle function at baseline and at follow up including: Isokinetic knee muscle strength, Isometric strength of trunk and lower extremity, single-leg hop for distance (SLHD), side hop, postural orientation errors (single leg-squat, stair descending, forward lunge, SLHD), hip and ankle range of motion, and muscular activation patterns.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients will be recruited from the Department of Orthopedics, Skåne University Hospital,
        Sweden and the Department of Orthopedics, Ullevål Hospital, Oslo, Norway. The majority of
        patients (approx. 80%) will be included in Sweden.

        Non-injured controls will be recruited among students at Lund University, Lund, Sweden.
      
Biospecimen description: 
      Whole blood, serum, plasma