Opening Wedge High Tibial Osteotomy (OHTO)

High Tibial Opening Wedge Osteotomy and Conservative Treatment in Medial Knee Osteoarthritis - A Randomised Controlled Trial

A prospective, randomised controlled trial where clinical and radiological outcome of high tibial opening wedge osteotomy with physiotherapy is compared to physiotherapy alone while treating symptomatic medial knee osteoarthrosis.

90 Symptomatic patients with mild to moderate medial knee osteoarthrosis are randomized to two groups: Group 1 (HTO-group) receive an diagnostic arthroscopy with high tibial opening wedge osteotomy (Tomofix-plate). Postoperatively a supervised physiotherapeutic rehabilitation program is started. Group 2 (FT-group) receive the same supervised physiotherapeutic rehabilitation program without the HTO or arthroscopy. Primary outcome measure is composite score of Knee injury and Osteoarthritis Outcome Score (KOOS5). Secondary outcome measures are pain (VAS), KOOS subscales, objective physical performance measurements, progression of osteoarthrosis (X-ray, MRI), change of mechanical axis, complications, treatment costs, rate of reoperation, revision to total knee arthroplasty (TKA), biological markers of arthrosis progression, 15D (quality of life assessment), QALY (Quality-Adjusted Life-Year), Work Productivity and Activity Impairment Questionnaire, Work Productivity and Activity Impairment Questionnaire, sum of governmental benefits received. Outcomes will be measured at 24, 60 and 120 months after the intervention.

Group receives opening wedge high tibial osteotomy with Tomofix -plate. Operative intervention is followed by supervised physiotherapeutic rehabilitation.

Time (seconds) taken to rise from a chair, walk 3 m, turn, walk back to the chair, then sit down wearing regular footwear and using a walking aid if required.

At 24, 60 and 120 month follow-up blood and synovial fluid samples are analyzed for HA concentration. This will be measured with antibody-ELISA at mg/g from 10µl of fluid. The same measurement will be conducted on blood serum.

At 24, 60 and 120 month follow-up blood and synovial fluid samples are analyzed for fatty acid (FA) profiling. FA will be analyzed from 75 µl of synovial fluid and 200 µl of blood serum with gas chromatography as mol-%.

At 24, 60 and 120 month follow-up synovial fluid samples are analyzed for composition. Synovial fluid composition will be assessed visually with confocal microscopy with a HA-biding fluorescent probe and Nile red probe that show both HA particles and the association of these particles on extracellular vesicles to assess the significance of vesicle-mediated HA secretion into synovial fluid.

At 24, 60 and 120 month follow-up blood and blood serum samples are analyzed for general variables reflecting inflammatory status (leucocytes, C-reactive protein, IL-6).

The amount of benefits are gathered from: The hospital discharge register (maintained by National Institute for Health and Welfare) National benefits paid by The Social Insurance Institution of Finland Pension decision made by Finnish Centre for Pensions

Inclusion Criteria: Pain: Subjective pain in the knee most of the month for at least one month during past 12 months. Knee range of motion (ROM) at least 5-120 degrees X-ray: medial joint space Altman > 1. Lateral joint space Altman < 2. Mechanical axis > 3 degrees varus alignment. Medial proximal tibial angle (MPTA) < 90 degrees age 25-55. Written consent, accepts both treatment arms. Exclusion Criteria: Pain is caused by something else than medial knee osteoarthrosis deficient ROM (flexion contracture > 10 degrees, flexion < 110 degrees) significant ligament instability post traumatic OA clinically relevant neurological disease (e.g. Alzheimer´s disease) clinically relevant metabolical disease (e.g. Diabetes) alcohol/drug abuse infectious/inflammatory joint disease previous knee area osteotomy or lower limb arthroplasty smoking (> 0 cigarette per day) obesity (BMI > 33) pregnancy or hope of pregnancy in the following two years