Mylène Jansen

KJD in regular care 121 6 Neither regular care versus trial treatment nor any of the other baseline characteristics had a significant influence on the 1-year change in total WOMAC score, neither in univariable nor multivariable models, or on being a responder. Experiencing pin tract infections or complications in general did not have a significant influence on 1-year WOMAC change or being a responder (all p> 0.2). Table 4 : Clinical outcome for patients treated with knee joint distraction in regular care and in clinical trials Regular care (n=41) Clinical trial (n=61) P- value WOMAC Total 22.2 (15.1–29.3)* 28.3 (23.5–33.1)* 0.080 WOMAC Pain 24.0 (16.2–31.9)* 29.5 (24.2–34.7)* 0.104 WOMAC Stiffness 20.4 (11.2–29.7)* 19.5 (12.9–26.1)* 0.463 WOMAC Function 21.9 (14.8–29.0)* 28.6 (23.7–33.6)* 0.069 Mean change and 95% confidence interval are given. Significant 1-year changes are calculated with paired t -tests indicated with * while the p- values indicate differences in 1-year changes between regular care and clinical trial patients, calculated with linear regression, corrected for baseline Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and distraction duration. Discussion Knee joint distraction is a relatively new, joint-preserving treatment for knee OA that after several clinical trials is now used in clinical practice to postpone a first TKA. This enabled evaluation if patients treated in regular care still have a similar indication profile, viz. similar characteristics as those treated in clinical trials and if KJD is still as clinically effective in regular care as it was shown to be in the trials. Despite the fact that regular care usually does not use selection criteria as strictly as clinical trials do, this study showed that the 84 patients treated with KJD in regular care between 2014 and 2018 had in general the same characteristics as the patients included in clinical trials the years before. Only the distraction duration was shorter in the regular care patients, which was expected because of the different protocol (eight weeks distraction instead of 6 weeks) used in the OPS. The fact that the distraction duration in regular care is longer than in clinical trials when excluding the OPS is probably a result of the dependence on OR planning in regular care and the difference, being on average 2.7 days on 6-week protocol, was limited. With an average intervention time of 53 minutes placing and 16 minutes removing the frame, the operative time is comparable to HTO and about half of the average time reported in literature for a TKA. 22–25 Complications were also described as similar to HTO and TKA 13– 15 , with pin tract infections, a common complication of external fixation in general 26 , being the most prevalent complication in KJD. Complications of treatment were comparable between KJD patients treated in regular care and those treated in trials. With 70% of patients experiencing pin tract infections based on oral antibiotic use, they occurred more often than