Jordy van Sambeeck

Chapter 6 88 Patients and Methods In our previous study we reported on 16 consecutive patients (19 knees) 16 . Inclusion criteria were objective patellar instability due to isolated trochlear dysplasia as established on true lateral conventional radiographs and closed physes. Patients were treated with a stand-alone anterior lateral femoral osteotomy without simultaneous procedures between June 1995 and October 2002 by the senior author (AK) (see: Operative Technique ). We approached all 16 patients (19 knees) to participate in this study. Two patients were unwilling to participate and 1 patient could not be contacted and was considered lost to follow-up. As already reported in our previous study 16 , one patient had a patellofemoral arthroplasty 3 years after her trochlear osteotomy, at age 46 years, due to progressive osteoarthritis. A grade 2 osteoarthritis on the Iwano scale was seen at time of the trochlear osteotomy and a grade 3 when she received the patellofemoral arthroplasty. She underwent a lateral release and medial reefing prior to her trochlear osteotomy. Because of the nature and inherent drawbacks of this procedure we were not able to compare her results (clinical, radiologic and functional scores) with the other patients. Follow-up could therefore be obtained in 12 patients and 15 knees. Fourteen knees were available for physical evaluation as one patient was unwilling to travel to our clinic. She did complete the scores and radiographs were performed elsewhere. The study had ethical approval (Registration number: NL48316.091.14) and all participating patients gave informed consent. Data collection was conducted at a single outpatient visit. Medical history since last follow-up and validated questionnaires were taken: late complications, subsequent surgeries, the number of recurrent dislocations, VAS pain and Lysholm 17 and WOMAC knee scores were recorded. The Kujala 18 score was not previously recorded but noted at final follow up to make our study results more comparable to other studies as all recent reports use the Kujala score. Physical examination of the knee was performed. In patients who had undergone bilateral surgery, each knee was evaluated separately. The function and stability of the knee were examined with tests for maltracking and instability including the apprehension test and the Rabot and J-signs. Conventional radiographs were taken in an AP, true lateral 19 and 30° patella skyline view. Osteoarthritis was graded using the Kellgren-Lawrence (K-L) scale 20 in the medial and lateral compartments of the tibiofemoral joint and using the Iwano scale 21 for the patellofemoral joint. The mean follow-up was 14.3 years (range 11.9 to 19.0 years). Mean age at follow up was 36.5 years (range 28.9-47.1 years). There were 3 males (4 knees) and 9 females (11 knees). Seven knees had realignment procedures of different kind prior to trochlear osteotomy. These included two Roux-Goldwaith procedures, two tibial tubercle transfers, one medial reefing and lateral release, one combined tibial tubercle transfer and medial reefing and one knee was treated with a medial reefing, lateral release and followed by a varus inducing osteotomy. In one knee only an arthroscopy was performed and 7 knees did not have any previous