Jordy van Sambeeck

A detaching, V-shaped tibial tubercle osteotomy is a safe procedure with a low complication-rate 4 59 Introduction Patellofemoral instability is a common problem in adolescents. In case of recurrent patellar instability, surgical management results in a lower risk of recurrent dislocation than conservative management [1]. Tibial tubercle osteotomy (TTO) is indicated in patients with recurrent patellar dislocations due to patella alta or an increased tibial tubercle trochlear groove (TT-TG) distance. Several types of osteotomies are described: the modified Elmslie-Trillat medialisation technique [2], the Fulkerson anteromedialisation technique [3], a sliding tibial tubercle osteotomy [4] and techniques in which the tibial tuberosity is completely detached [5]. A systematic review by Payne et al. concluded that the risk of complications is related to the employed technique [6]. In his review the complication rate lies between 3.3 and 10.7%. When performing a V-shaped TTO, the tibial tubercle with periosteum is completely detached from the tibia and a step cut osteotomy is used [7]. Some authors suggest that maintaining the medial and/or distal periosteum at the tubercle when performing an osteotomy is crucial for preserving the vascularization and osteotomy union [8, 9]. Also, the fear of causing a tibial stress fracture when using a step-cut osteotomy lives among surgeons [10]. Payne et al. stated that osteotomies that involve complete detachment of the tubercle have an increased risk of non-union and tibial fractures compared with those in which a distal cortical hinge is maintained [6]. However, the hypothesized advantages of the V-shaped TTO are that the risk on non-union is low due to the triangular shape of the bone block with a twice as big bone contact area of trabecular bone and the intrinsically stable nature of the shape of the osteotomy in comparison to a sliding flat osteotomy. Only small sample size studies have been performed on this subject to our knowledge [5, 11]. Large studies reporting complication rates of a V-shaped tibial tubercle osteotomy are missing, but necessary to give a clearer view on this and can help determine the optimal technique. The aim of this study was to report complication rates directly related to the surgical technique of a V-shaped TTO, where the tubercle is completely released from its periosteum using a step-cut osteotomy. Material and methods Data collection All patients operated between March 2004 and October 2017 in the Radboud University Medical Centre, Nijmegen, using a V-shaped tibial tubercle osteotomy (TTO) were included. The indication for a tibial tubercle transfer was recurrent patellar dislocations in combination with a patella alta (Caton-Deschamps index > 1.2), as underlying anatomical risk factor after failure of conservativemanagement with or without an increased TT-TG distance. Two experienced surgeons using a similar surgical technique performed all procedures. Additional simultaneous procedures were performed if indicated such as a medial patellofemoral ligament