Jordy van Sambeeck

Chapter 1 20 Treatment Tibial tubercle osteotomy and trochleoplasty Treatment of patients with patellofemoral instability is challenging due to the many interacting factors that can contribute to the pathology of an individual patient. In a recent thesis on treatment of patellofemoral instability, Rood et al. formulated an algorithm for treatment of objective lateral patellar dislocation based on clinical experience and studies in the thesis which may help to identify the specific treatment for an individual patient with certain pathology. Treatment after a first time lateral patellar dislocation starts non-operatively. The optimal non-operative treatment is functional treatment with minimal immobilization of the knee and stimulating early active rehabilitation 20 . For patients with recurrent patellar instability despite adequate non-operative therapy, surgical treatment can be considered. Different procedures may be combined, the corner stone of optimal patella stabilizing surgery is reconstruction of the medial patellofemoral ligament. This can be combined with a procedure which addresses the bony anatomy such as a medializing and/or distalizing tibial tubercle osteotomy (TTO) and a trochleoplasty. In some cases even distal femoral osteotomy could be added correcting for rotation or malalignment in the coronal plane. In this thesis the trochlear osteotomy and tibial tubercle osteotomy will be addressed. A more general term for trochlear osteotomies or procedures which modify the trochlea is ‘trochleoplasty’. Trochleoplasty procedures are technically challenging procedures. Different techniques have been described historically 21 . The different techniques could be categorized in trochlear deepening and lateral facet elevating or elongating techniques (figure 8). The general aim of a trochleoplasty is to reshape the trochlear groove in a way that the patella engages into the trochlear groove in early flexion and is then restrained from lateralization during the whole arc of motion of the patella when flexing and extending the knee. Trochleoplasties are intra-articular osteotomy procedures and have inherently a risk of damaging the patellofemoral joint during the procedure. Despite a careful surgical technique, possible complications could include osteochondral damage, osteochondral fracture, osteochondral necrosis or ligamentous damage. Extensive intra- articular procedures such as a trochleoplasty could also have an increased risk on arthrofibrosis (causing stiffness) of the knee. Besides the direct and short term complications, modification of the trochlea could also have long term effects. The congruency of the patellofemoral joint is modified only at the trochlear side and not on the patellar side. There may be a relationship between patella and trochlea morphologic development during growht 22 . So, modifying only the trochlea results in some kind of increased incongruency of the joint. This could, amongst other factors or complications, possibly lead to early patellofemoral osteoarthritis.