Mylène Jansen

172 Chapter 9 Treatment KJD was performed according to a standardized surgical protocol. 12,15 In short: fixating the external distraction device to the femur and tibia medially and laterally using bone pins, placed in pairs at 4 different locations (tibia/femur and medial/lateral). After positioning, a distraction distance of 2 mm was applied intra-operatively. After surgery, patients stayed in the hospital for another 2 to 3 days, during which the device was gradually distracted further until 5 mm distraction was reached. Afterwards, the distraction distance was checked on weight-bearing radiographs and adapted if needed. During the 6-week distraction period weight-bearing was encouraged, supported by crutches if needed. After 6 weeks, the distraction frame was removed and knee manipulation (flexion-extension) was performed at day-treatment. Procedures were identical for the KneeReviver prospective study and the 2 RCTs using the Dynamic Monotubes. Clinical and radiographic evaluation For this interim analysis data was collected for included patients at screening, directly before placement of the KJD frame, and 1 year after treatment. At all 3 time points, patients filled out the Knee injury and Osteoarthritis Outcome Score (KOOS) and VAS of pain. The Short-Form 36 (SF-36) was filled out at screening and 1 year after treatment. The KOOS questionnaire was used to calculate the total WOMAC scale and its subscales (pain, function, stiffness). From the SF-36, the physical component scale (PCS) and mental component scale (MSC) were calculated for quality of life analysis. For the KOOS/WOMAC and VAS, the results at screening and directly before frame placement were averaged to obtain the baseline clinical results. For the WOMAC, KOOS and SF-36, higher values indicate a better condition, while for the VAS lower values indicate a better condition. Standardized weight-bearing, semi-flexed posterior-anterior radiographs were performed according to the Buckland-Wright protocol at screening and at 1-year follow-up. 16,17 Images of all included patients were checked in pairs for consistency of acquisition between baseline and 1 year follow-up by 2 observers (MJ, FL; blinded to any data) and excluded in case of considerable inconsistencies. The most affected compartment (MAC) and least affected compartment (LAC) were determined visually from the radiographs. Images were evaluated using knee images digital analysis (KIDA) software to analyze the JSW; an aluminum step wedge was used as a reference standard. 18 Calculated JSW parameters were the minimum JSW, the MAC JSW and LAC JSW, and the mean joint JSW. All image analyses were performed by a single, experienced observer, blinded to patient characteristics, and the intra-observer variation of this measurement method was shown to be good (for all different parameters ICC = 0.73–0.99). 18 Data collection and evaluation were identical for the KneeReviver prospective study and the 2 RCTs.