Mylène Jansen

Two-year results of KJD compared with HTO and TKA 63 4 The similarities and differences in selection criteria of both trials are listed in Table 1. In both trials, insuperable, patients and physicians were aware of treatment assignment after allocation. The statistical methods of the patient selection and randomization process have been described elaborately before. 11 Both trials were performed in accordance with the ethical principles from the Declaration of Helsinki and all patients gave written informed consent. 11 Treatments TKA was performed using the Genesis II posterior stabilized system (Smith & Nephew, Warsaw, Indiana) with fixation using GentaPalacos cement (Heraeus, Hanau, Germany). For HTO treatment, bi-plane medial-based opening-wedge osteotomy was performed. TomoFix medial high tibial plates and screws (DePuy Synthes, Switzerland) or Synthes locking compression plate system (DePuy Synthes, Switzerland) were used for fixation. The method of Miniaci 15 was used to preoperatively define the size of the opening. After both TKA and HTO, routine rehabilitation and thrombo-embolism prophylaxis was provided after surgery. Distraction surgery was performed with a proof-of-concept device consisting of 2 dynamic monotubes (Triax, Stryker, 45 kg spring with 3 mm displacement) bridging the knee joint medially and laterally. Each monotube was fixed to 2 bone-pins on each end (tibia and femur). The tubes were distracted by 2 mm during surgery and by 1 mm every day post-surgery, until a total distraction of 5 mm was reached, confirmed on radiographs. Afterwards patients were discharged, with heparin prescribed for 9 weeks, and allowed full weight-bearing of the distracted knee, supported by crutches if needed. At 3 to 4 weeks after surgery, radiographic evaluation of distraction and clinical evaluation of pin tracts was performed in the outpatient clinic. After 6 to 7 weeks the frame and pins were surgically removed. Patient-reported outcome measures Primary outcome was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC, version 3.1) to score clinical improvement. As secondary measures, we used the validated Dutch Knee injury and Osteoarthritis Outcome Score (KOOS) (normalized to a 100-point scale; 100 being the best condition); the Intermittent and Constant Osteoarthritis Pain score (ICOAP) for the knee was assessed (0–100, 0 reflecting no pain); a Visual Analogue Scale for pain (VAS pain; 0–100 mm, 0 reflecting no pain); the EuroQol (EQ)-5D-3L for quality of life (transformed to an EQ-5D index score; 0–1, 1 being the best); and the Short Form 36 (SF-36) for general health (transformed to the physical (PCS) and mental (MCS) component summary score; 0 – 100, 100 being the best). All clinical outcome parameters were assessed at baseline (0), and after 3, 6, 12, 18, and 24 months except for the SF-36, which was not assessed at 3 months (no change within this time period for the SF-36 anticipated).