Maarten van Egmond

138 Chapter 6 Within the intervention group, most of the functional outcome measures significantly improved between T0-T1 and T1-T2, apart from ADL that significantly decreased during the first 6 weeks of the intervention and restored in the second period of 6 weeks. A possible explanation could be that after T0, patients mostly stayed at home because they felt too weak to keep up with their ADL. Moreover, in the first 6 weeks, the telerehabilitation intervention primarily focused on increasing muscle strength of the lower extremities. After 6 weeks, the shift was gradually made toward implementing the exercises in daily life, finally resulting in a significant increase in ADL in the second period of 6 weeks. Limitations This study has intrinsic limitations. First, only 22 patients were included in this study, of which 15 patients completed the study. This might limit the generalizability of our findings. However, despite the small sample size, the included participants represented the population of interest in terms of baseline characteristics and postoperative complications. Moreover, inclusion was terminated after the inclusion of the 22 nd participant, because no new findings were to be expected with adding new participants to the study. Second, this study was not a pilot feasibility trial, where patients were randomly assigned either to the intervention group or a control group to determine effectiveness of the investigational treatment. Instead, we compared the intervention group with a matched historical comparison group. Therefore, bias could not be ruled out completely. We were not able to compare functional status outcome measures half way through the telerehabilitation intervention because the historical controls were not measured T1. Third, patient satisfaction was measured with a modified TSUQ that had not been validated in this specific population. Kairy et al. 33 concluded in their systematic review investigating clinical outcomes, clinical process, health care utilization, and costs associated with telerehabilitation that patient satisfaction ratings were generally high, irrespective of the population. However, they also stated that operationalization and standardization of satisfaction were frequently lacking and too much focus was on the technology part instead of aspects of service delivery. The satisfaction questionnaire we used addressed both aspects, and therefore, we are confident that the satisfaction ratings were representative of the telerehabilitation intervention provided.