Jordy van Sambeeck

Chapter 4 64 Discussion The major findings of this study are the low incidence of non-union and tibial fractures. Kanamiya et al suggest that when a complete detachment of the tibial tubercle is performed and the medial, lateral and distal periosteum is transected, this leads to a complete arrest of the blood flow and a higher chance of non- union [8]. From our data we cannot confirm this theoretical concept in practice. Compared to the non-union rate of 0.8% in 787 TTO’s published by Payne et al. [6] in their systematic review, the incidence in our group (0.38%) is even lower. This could be due to the bigger contact area of the V-shaped osteotomy with more trabecular bone for better bone healing (figure 2). a. b. c. Figure 2. Three-dimensional schematic imaging of the TTO technique before (a), during (b), and after (c) the V-shaped osteotomy. Secondly, tibial fractures were only seen in 0.76%, again less than reported by Payne et al. [6] (2.4% when using a detached TTO) or Luhmann et al. [10]. There were no early tibial fractures. After the second tibial fracture, the aftercare was changed where instead of 50% only 10% of weight bearing was allowed for six weeks. Although both tibial fracture were seen after this first six weeks, we think that protecting the tibia in the first stadium of bone healing will give less excessive stress on the damaged cortex at the distal cut, which is perpendicular to the shaft, and so prevents tibial shaft fractures. In both cases, the piece of bone that was resected was not placed back proximally because it did not fit. This might have caused a lack of stability, which could be the reason the tibial shaft broke. Secondly, it is very important to make the distal cut carefully and not too far into the cortex of the tibia. If this happens, this will be the weak spot for stress rising.