Jordy van Sambeeck

Chapter 4 62 Patient characteristics Number of patients 203 Number of knees 263 Mean age (range) 20.5 (12-49) N patients (%) Female 194 (74) Additional procedures performed None 123 (46) VMO plasty 51 (19) Trochlear osteotomy 50 (19) Lateral release 16 (6) MPFL reconstruction 7 (3) Combined 80 (30) Table 1. Descriptive statistics Major complications Thirteen knees (4.9%) had a major complication. An overview of complications is displayed in table 2. Two patients (0.76%) sustained a tibial shaft fracture at the side of the step cut performed during the transfer surgery. The first patient while jumping on one leg during rehabilitation 2.5 months after surgery, the other after 6.5 months after a fall. Both fractures were stabilized with a locking compression plate. There were two cases in which there was a problem with the part of bone removed from the distal side that was pressed into the proximal part of the osteotomy. In one patient the bone block became a loose body that was removed arthroscopically. In the second case this bone block was malpositioned directly underneath the patellar tendon and caused tendinopathy, and was surgically removed. There was one case of septic arthritis (0.38%) and one with a non-union (0.38%). The patient with a non-union was re-operated after 9 months. A fibrous layer on the V-shaped fragment was excised and a third screw was placed to increase stability, this resulted in consolidation after 5 months. Proximalisation of the tubercle without screw breakage was seen in three patients (1.14%), this was recognized after 10 days, 3 weeks and 3 months; all three patients had the screws revised after which the osteotomy fully consolidated. In one patient the malunion was seen after 4 years after a recurrent patellar dislocation. The bone was healed, but during the growth the screws were pulled oblique so the tubercle proximalised again. A correction TTO was performed. Screw breakage occurred only once, discovered 6 months after surgery but with consolidation of the osteotomy and a Caton index of 1.1 so no further action was needed. In one case the tibial tubercle fractured three days after surgery because of an epileptic insult with maximum quadriceps contraction so it was fixated with a small buttress plate.