Jordy van Sambeeck

Chapter 9 150 As outlined in the introduction of this thesis, the occurrence of major osteotomy specific complications after a TTO might be related to the technique that is performed 5 . Nonunion and fracture are two complications that could be related to surgical technique and postoperative care. The studies in chapter 3 and 4 do not answer the question on how these different techniques affect blood supply and biomechanical strength. It does answer the final outcome in terms of rates of nonunion and postoperative fracture. Both techniques have a low rate of nonunion (maximum 0.6%) and postoperative fracture (maximum 0.8%). For the self-centering sliding TTO it is essential to maintain the blood supply from the medial periosteum. The V-shaped TTO receives enough endosteal blood supply due to the large contact area of trabecular bone that is created. We conclude that both techniques are safe techniques with a low rate of nonunion and fracture. The decision on which technique to perform could be based on the goal of the osteotomy (medializing and/or distalizing). When only distalization is required, both the self-centering sliding TTO and the V-shaped TTO are good options. The self-centering TTO has the advantage of centering the patella, which is inherently part of the technique. When additional or only medialization is required, the self- centering sliding TTO is the preferred technique. Trochleoplasty Research questions: 1. What is the effect of age on patient reported outcome after a lateral facet elevating trochlear osteotomy? (Chapter 5) 2. Do the clinical and radiological results of a lateral facet elevating trochlear osteotomy deteriorate in patients with a minimum of 12 year follow-up? (Chapter 6) 3. What is the rate of complications after various techniques used for trochleoplasty? (Chapter 7) In Chapter 5 of this thesis, we analyzed the effect of age on the patient reported outcome of a lateral facet elevating trochlear osteotomy. The outcome of 125 surgical procedures was evaluated. In our cohort of patients with a mean age of 19.8 years (range 12.5-46.3) at surgery, multivariable regression analysis revealed a correlation between age at time of surgery and VAS pain at rest. The clinical relevance of the small increase is doubtful. Age at time of surgery did not have a significant effect on the other outcome measurements. The mean KKS in our study was 73, which is acceptable in our opinion. A notable result of this study was the rate of patella redislocation (13 patients, 10%). These patients were relatively young. The average age of these patients with