The Effect of Corrective Osteotomy on in Vivo Cartilage Mechanobiology in Patients With Knee Osteoarthritis
Condition: Knee Osteoarthritis
MeSH terms: Osteoarthritis; Osteoarthritis, Knee
Study type: Observational

Summary: 
      Our overall hypothesis is that a sudden ambulatory load reduction (caused by corrective
      osteotomy) leads to changes in cartilage biology that delay or reverse osteoarthritic
      processes determining the clinical outcome and representing an in vivo model for assessing
      cartilage mechanosensitivity.
    

Detailed description: 
      Although osteoarthritis (OA) is the most common degenerative joint disease and despite
      international research efforts, to date the factors involved in the initiation and
      progression of this debilitating disease are poorly understood, diagnostic markers are
      lacking and there is no cure. High tibial osteotomy (HTO) is a well-accepted therapy for
      patients with knee OA and varus alignment aimed at re-establishing a more even distribution
      of ambulatory load between the affected medial knee compartment and the lateral knee
      compartment. However, the survival rate of HTO is only around 75% after 5 years. There is
      some evidence that the change in ambulatory load after HTO may be more relevant than the
      post-operative static alignment although this relationship has not yet been investigated.
      Because of the large changes in ambulatory load with HTO, the investigators propose that
      corrective osteotomy may serve as a valuable model for studying the effect of changes in
      ambulatory load on in vivo cartilage mechanobiology in patients with knee osteoarthritis. Our
      previous work has shown that serum biomarkers for cartilage increase after a 30-minute
      walking exercise (termed 'walking stress test') and indicated that these changes may be
      associated with the accumulated ambulatory load during the test.

      Patients with medial compartment knee OA and varus alignment will be clinically assessed
      (including mechanical axis measurement from radiographs) and complete questionnaires on
      physical function prior to corrective osteotomy. Patients will complete a walking stress test
      with blood sampling to assess load-induced changes in serum biomarker concentrations, and
      undergo gait analysis to assess the external knee adduction moment. Once full load bearing is
      achieved, the mechanical axis will be measured from radiographs. Patients will complete the
      questionnaires and a second walking stress test with blood sampling and undergo gait analysis
      6 months after corrective osteotomy. At the 12-month follow-up, subjects will complete the
      questionnaires.
    

Intervention name(s): Corrective osteotomy
Intervention type(s): Procedure
Intervention description(s): corrective osteotomy for varus alignment
Other intervention name(s): Corrective osteotomy (CO)
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        patients with knee osteoarthritis scheduled for corrective osteotomy
      
Biospecimen description: 
      serum, synovium biopsies