Mylène Jansen

178 Chapter 9 Discussion As hypothesized, patients treated with KJD using the KneeReviver, which was developed with input of surgeons, patients, and engineers and with CE certification and the intended use ‘knee joint distraction’, showed significant clinical benefit 1 year after treatment. Almost all evaluated parameters, both regarding clinical outcome measures and tissue structure repair, showed a statistically significant improvement at 1-year follow-up. Effects were not statistically significantly different when compared to patients previously treated with the Dynamic Monotubes (originally designed for trauma surgery). The only parameter that did not show a significant change in both groups was the mental component scale of the SF-36. This is anticipated since this parameter is insensitive to knee OA treatments in general, as HTO or TKA did not induce a change in this parameter either. 8–10 Although the 1-year results between the 2 frames were not statistically significantly different, the second hypothesis could only partially be confirmed as the total WOMAC, being 1 of the primary outcome parameters for which the study was powered, was inconclusive when corrected for baseline in the non- inferiority evaluation. Changes in all other outcome parameters 1 year after treatment, including minimum JSW as the other primary outcome parameter, were shown to be non-inferior for patients treated with the KneeReviver as compared to the Dynamic Monotubes. However, it should be mentioned that the difference between the 2 treatments in minimum JSW change was in favor of the Dynamic Monotubes and the non-inferiority level was taken quite liberally. Complications were not directly compared between trials, but as reported previously in patients treated with the Dynamic Monotubes, pin tract infections were the most occurring complication and a relatively high number of patients experienced them. 22 In order to decrease treatment burden, this number should be reduced as much as possible. One option may be including the use of cadexomer iodine ointment in the wound care protocol during treatment, as this has shown a significant reduction in pin tract infections in patients treated with KJD. 23 While these first analyses show positive results for the KneeReviver, the long-term results will become the most interesting. Previous analyses have shown that the first-year increase in minimum radiographic JSW is predictive of long-term survival of KJD treatment (viz. the duration till TKA after KJD). The chance of being without a prosthesis 9 years after KJD treatment was significantly higher for patients with a larger initial JSW increase. None of the patients with a first-year minimum JSW increase of less than 0.5 mm had their native knee 9 years later. 7 Patients treated with the KneeReviver showed a smaller average minimum JSW increase in the 1 st year, 0.4 mm compared to 0.6 mm for the Dynamic Monotubes. It has also been shown that more severely affected joints show a better tissue repair response. 24 Compared to patients treated with the Dynamic Monotubes, the KneeReviver patients seem to have less affected joints with respect to baseline JSW with 1 mm versus 0.5 mm for the minimum JSW and 2.7 mm versus 2.2 mm for the MAC JSW, both nearing statistical significance. As such,