Jordy van Sambeeck

Age at surgery is correlated with pain scores following trochlear osteotomy in lateral patellar instability 5 79 this in mind, a redislocation rate of 10% can be seen as proof of the effectiveness of a trochlear osteotomy in terms of stability. The mean KKS in our study was 73, this is an acceptable score in our opinion. The systematic review of Balcarek et al. demonstrates higher KKS-scores after trochleoplasty procedures (range 81-92) 33 . However, due to the inclusion- and exclusion criteria (for example the exclusion of studies in which treatment included additional procedures) of their review, it´s difficult to compare our cohort with the studies they have included. Loss in range of motion occurred in four patients (2%), which was lower in our study than in previously published reports 17 . The standard use of a CPM might have contributed to this. Four patients had a complication related to the TCP- wedge. The results of our study, including a relatively high rate of patellar redislocation and KKS of 73, emphasizes that patient selection and strict indication for this type of trochleoplasty is highly important for a better outcome. A recent consensus statement from the AOSSM/PFF Patellofemoral Instability Workshop stated that trochleoplasty is rarely indicated in patients with patellar instability 34 . In determining whether surgery for recurrent patellar instability is warranted, trochlear morphology, patellar height, lateralization of the tibial tubercle, sufficiency of the MPFL, age and gender should be considered. None of the different types of dysplasia according to the Dejour were correlated with outcome measurements of this study. The indications for a lateral facet elevating trochlear osteotomy have decreased in recent years. However, we think that there is still a place for this type of trochlear osteotomy in patients with recurrent patellar dislocation with a J-sign at physical exam, underlying trochlear dysplasia without a trochlear bump but with a convex proximal trochlea. In these cases, outcomes are most predictable and the risk of serious complications is low. This is the first study to investigate the effect of age on the postoperative outcomes of a lateral facet elevating trochlear osteotomy. The strength of this study is the large patient cohort and the use of PROMs which reflect the outcome as experienced by patients and not based on radiographs assessed by clinicians. Despite the minimal number of indications, we are convinced that it´s important to present the outcomes of this type of trochlear osteotomy, studied in a large cohort, in the perspective of personalized treatment for the individual patient. Our study has also some potential limitations. First, our study population was heterogenic (e.g. different types of dysplasia, multiple additional procedures, etc.). Although intrinsic heterogeneity in patient characteristics and treatment strategy exists in this study, we think that this population reflects the patients seen during daily practice. Second, patients were not physically examined by a clinician. Our study demonstrates that patient reported outcomes, in conjunction with