Jordy van Sambeeck

Summary, general discussion and future perspectives 9 149 − MRI ° Patient supine with knee in 10° flexion ° 3D morphology of trochlea ° PTI and 3D measurement patellar height ° 3D measurement lateralization Tibial tubercle osteotomy Research questions: 1. What is the incidence of postoperative complications, specifically fracture and non-union, after a self-centering tibial tubercle osteotomy? (Chapter 3) 2. What is the incidence of postoperative complications, specifically fracture and non-union, after a V-shaped tibial tubercle osteotomy? (Chapter 4) In Chapter 3 and Chapter 4 the risk of procedure specific postoperative complications of respectively the self-centering sliding tibial tubercle osteotomy (TTO) and V-shaped TTO are quantified. In Chapter 3 the results and complications in a large case series (447 patients, 529 knees) on the self-centering sliding TTO are presented. Major complications related to the osteotomy were reported in 9 cases (1.7%). These include 3 patients with a non-union and two patients with a fracture of the tibia/tibial tubercle during follow-up both at the site of previous realignment surgery. In Chapter 4 the study on the rate of complications after a V-shaped TTO is presented, this study includes 263 knees in 203 patients. Major complications occurred in 13 knees (4.9%). Two patients sustained a tibial shaft fracture. In two cases, there was a problem with the part of bone that was replaced proximally after removal from the distal side of the osteotomy, needing further surgery. There was one patient with a septic arthritis and one patient with a non-union. In three patients, proximalization of the tibial tubercle without screw breakage was seen. The main weakness of both of these studies is the retrospective design. All currently available patient records were reviewed; however, a few cases might be lost due to registration bias. Both of the studies were performed in hospitals with a specialized character of clinical practice on patellofemoral instability. This focus has led to a good administration of surgical treatment and follow-up of these patients. This has also led to the distinct advantages of these studies such as the large sample size with a uniform technique of TTO and protocolized postoperative care.