Mylène Jansen

Return to sport and work after KJD and HTO 87 5 Introduction Demand for knee arthroplasty (KA) is rising worldwide, especially in younger patients. If this trend continues, by 2035 up to 50% of KAs will be performed in patients younger than 65 years of age. 1–3 Younger knee osteoarthritis (OA) patients are generally more active, are often still working and therefore frequently have high demands and expectations from their surgery. 4,5 Also, KA patients 50–65 years of age have a significantly increased risk of revision surgery, compared to older populations (>65 years), with 1 study reporting a lifetime revision risk of 1 in 3 in patients aged 50–55 years. 6,7 Also, higher rates of dissatisfaction have been reported in younger patients 8 , and up to 50% of younger patients reported residual symptoms and limitations after contemporary total KA. 9 Hence, performing KA in this younger active population is unappealing to many surgeons, and as a treatment not a guarantee for satisfaction and return to desired activities for patients. Consequently, KA is often postponed in younger patients with severe functional limitations, who now find themselves trapped inside the so- called ‘treatment gap’. 10,11 To address this gap, the global interest for joint-sparing alternatives has significantly increased. Cartilage regeneration techniques are progressively studied, but still lack the scientific basis to justify broad implementation of these techniques in clinical practice. 12–14 However, osteochondral allograft transplantation techniques can successfully restore joint function in young (up to 55 years of age) and active patients with large focal or multifocal articular cartilage lesions. 15–17 High tibial osteotomy (HTO) has also been increasingly advocated to treat this younger patient population 18,19 and thus expected to rise in the coming years. The pooled 10-year HTO survivorship, using KA as an endpoint, was 92% for opening-wedge HTO and 85% for closing wedge HTO. 20 Also, rates of return to sport (RTS) of 82–85% and return to work (RTW) of 85–95% have been reported after HTO. 21–23 Knee joint distraction (KJD) is a less well-known but promising alternative joint-sparing treatment option in relatively young osteoarthritis patients with severe complaints. With KJD, an external distraction device creates a temporary load reduction between focal areas of cartilage surfaces in the knee. 24 Intema et al. showed that KJD treatment resulted in radiographic improvement of joint space width (JSW) and increased cartilage thickness on MRI, indicative of tissue structure modification that may have beneficial effects on patients’ knee pain and symptoms. 25 A preserved treatment effect up to 5 years has been described, with increased minimum JSW at 5 years post-treatment compared to pre-treatment. 26 In addition, a randomized controlled trial (RCT) comparing KJD with HTO, for patients with medial compartment OA who were eligible for HTO, reported similar improvements for both groups in patient-reported clinical outcomes including the KOOS, WOMAC, VAS pain scores and