Jordy van Sambeeck

Trochleoplasty procedures show complication rates similar to other patellar stabilizing procedures 7 115 This is low compared with the natural course after patellar dislocation, or patients treated non-surgically being up to 24% according to Smith et al. 1, 37, 38 . From these results, it could be hypothesized that these two trochleoplasty techniques are successful in preventing recurrent dislocation and/or instability symptoms, also compared with other surgical interventions. Seven studies did not report about the presence of PF OA. The rate of development of PF OA would probably increase at longer follow-up, as the development and progression of PF OA in these patients depends on multiple factors, not only a stable patella. Registration of patellofemoral osteoarthritic changes on imaging does not mean that patients have complaints related to PF OA. The number of PF OA should be interpreted as an objective outcome measure and not as a clinically relevant outcome measure if it is asymptomatic. Most of the studies included in this review were not designed to detect PF OA as an outcome measure. The proportion presented in our results could be an underestimation of the true incidence of PF OA and should be interpreted with caution. Rare complications that were reported include medial subluxation 14 , patella baja 23 and venous thrombotic events 2, 13 , none were catastrophic. There was no mortality associated with trochleoplasty. One should be aware that these and potential other rare complications can occur after a trochleoplasty since it is a very complex procedure. Some potential limitations of our study have to be discussed. Despite the heterogeneity of the cohorts between studies of different techniques a meta- analysis was performed. Since no comparative studies are included, no direct comparison between different techniques could be made. No conclusion can be drawn as to whether one of the techniques is superior to the other in terms of complications of surgery. Furthermore, there is no clear consensus on the indication for trochleoplasty surgery, which makes a direct comparison between studies and/or techniques very difficult. The presented complications for different techniques should be interpreted in the context of the individual studies that have been published, including exact indication for surgery, duration and severity of symptoms, and patient factors. The definition of complications is always arguable and will differ between different clinicians and patients. Mild residual symptoms such as pain, swelling or clicking were classified as an outcome of surgery and not as complication of surgery. Some complications cannot be definitely assigned to either the trochleoplasty or the additional procedure, this introduces most likely some bias in complication rate. It should be noted that the absence of complications does not mean that a patient is free of complaints. The rate of complications found in this review is acceptable, but trochleoplasty is still a rather radical surgical procedure with significant risks.