Jordy van Sambeeck

Chapter 7 116 Almost all studies were retrospective or prospective case series. None of the studies were randomized or described a difference between two cohorts. Because of this lack of methodological quality, we did not perform a quality assessment; all studies were regarded low-level evidence. Publication bias may be present since “negative” results of case series of surgical procedures are less likely to be submitted for publication. Measurement bias may have occurred due to failure of thorough administration of complications, especially forminor complications in retrospective studies also due to diligence and increased awareness of the screening resulting in higher report of complications. There might also be sampling bias, since most surgeons who performed trochleoplasty in the articles in this review were experienced surgeons, thus the number of complications might be an underestimation of the true number. With the limited high-quality evidence available, we think the results of this study a sufficiently accurate represent the complication rate after trochleoplasty procedures including any additional procedures. Conclusions This systematic review and meta-analysis demonstrates that the complications after a Bereiter and Dejour trochleoplasty including additional procedures are in the range of those of other patellar stabilizing procedures. For four other techniques, no meta-analysis could be performed. Competing interests We have received no funding for this study and have no competing interests to declare. Authors’ contributions JvS, SvdG, NV and GH designed the study and drafted the research protocol. JvS and SvdG performed the literature search, selection, data extraction and drafted the manuscript. JvS and GH developed the search strategy and performed the data analysis. JvS, SvdG, NV and GH contributed in the interpretation of the data. SvdG gave final approval of the version to be submitted. Acknowledgements We thank Alice Tillema, Medical Information Specialist, Medical Library, Radboud university medical center, Nijmegen, the Netherlands, for her help during the development of the search strategy.