Jordy van Sambeeck

General introduction 21 1 Figure 8. Lateral facet elevating trochlear osteotomy. The osteotomy is performed with osteotomes, the proximal is further advanced medially than the distal osteotome. A triangular bone graft or tricalcium phosphate wedge is used to hold the achieved correction. Historically there have been multiple procedures addressing lateralization of the patellar tendon insertion. A bony procedure is preferred due to the better healing potential of bone compared with tendons and more accurate measurable correction, bony procedures are consequently the most often described option in recent literature. Some bone-specific complications of surgical intervention include fracture and non-union. Different surgical techniques may lead to a different amount of these bone-specific complications. Factors that could contribute are disruption of blood supply to the bony fragment or technique of fixation. The occurrence of major procedure specific complications after a TTOmight be related to the technique that is performed 23 . Nonunion and fracture are two complications that could be related to surgical technique and postoperative care. Bone healing can occur as primary or as secondary bone healing, these are different methods of healing, which require different methods of immobilization. For the TTO primary bone healing is the desired method of bone healing, requiring absolute stability and compression over the ‘osteotomy’. This is accomplished by using lag screws as fixation. Next to the method of stabilization, there needs to be enough blood supply to the osteotomy supplying nutrients and oxygen which are essential for healing. Blood supply to the bone can be either periosteal or endosteal. Surgical dissection interferes with the blood supply of the bone. Different techniques can differently affect these ways of blood supply and could therefore theoretically lead to different rates of (non)union. Next to the effect on blood supply, different