Jordy van Sambeeck

Complications of a self-centering sliding tibial tubercle osteotomy for patellofemoral complaints 3 53 These findings are in line with results published in previous literature, describing a higher change of decreased ROM after all types of trochlea osteotomy and after MPFL reconstruction 13-15 . Patients with preoperative patellofemoral pain and female patients had a higher chance of postoperative hardware removal. Depending on imaging alone for the degree of correction, has a risk of overcorrection of the tibial tubercle in medial direction, which might lead to medial dislocations or hypothetically to higher joint pressure and consequently early patellofemoral osteoarthritis. To prevent overcorrection, other authors use different intra operative measurements. Recently Arendt described a new physical exammeasurement, the tubercle-sulcus angle (TSA), which can be performed in the operating room 16 . With a self-centering sliding technique overcorrection in medial direction is highly unlikely and intraoperative measurement are unnecessary. In our cohort, there were no postoperative medial dislocations. In a previous article on this technique, there was only a modest increase in radiological patellofemoral osteoarthritis of 0.35 with a maximum of grade 2 on the Kellgren-Lawrence scale at ten years follow up 6 . Limitations The main weakness of this study is its design, a historical case series with heterogenic additional procedures. However, data on complications and recurrent dislocations were collected prospectively, and all patient records were reviewed to avoid data loss and prevent underestimation of early complications. Although it was not the goal of this study to evaluate patient reported outcomes, its absence is a weakness of the study. As well as the lack of postoperative CT or MRI to measure difference in TT-TG. A distinct advantage of this study is its large sample size, uniform technique of tibial tubercle osteotomy and protocolized postoperative care. Competing interests We have received no funding for this study and have no competing interests to declare. Authors’ contributions JS and SK initiated the study by defining the research question and purpose of the study. JS performed data collection and analysis and drafted the manuscript together with AR. SK was the first author to review drafts of the manuscript and gave final approval of the version to be submitted. SG and ST were second reviewers of drafts of the article and added important feedback for interpretation of the results and for discussion section.