Jordy van Sambeeck

Twelve year follow-up of a stand-alone lateral condyle elevating trochlear osteotomy 6 87 Introduction Patellar instability is associated with a number of predisposing factors 1 with trochlear dysplasia as the largest contributor to prevent the lateral patellar displacement 2, 3 . In patients with persistent patellofemoral instability due to trochlear dysplasia, a trochleoplasty can be an effective way to permanently regain stability 4, 5 , especially in cases with high grades trochlear dysplasia or in cases where other procedures have failed 6 . Based on the Dejour classification 7 , a trochleoplasty can be indicated in trochlear dysplasia grade B,C and D 6, 8, 9 . The main goal of a trochleoplasty is to restore the lateral bony restraint to normal biomechanical parameters. Due to the nature of this procedure, it could potentially lead to cartilage damage and an increased risk of early osteoarthritis as it changes the congruency of the articulating surface of the distal femur 9 . Multiple techniques and specific procedures have been described 6, 9-12 . Opposed to a sulcus deepening trochleoplasty, a procedure in which the central part of the trochlea is deepened 9 , another option is to raise the lateral side of the trochlea through an elevating anterior lateral femoral condyle osteotomy. A primitive version of this technique was described by Albee in 1915 12 . Although most review articles mention this technique as a reasonable option 8 , literature on the results of this technique is limited 13, 14 . The only two previous reports are of poor methodologic quality and included only a few patients. The general perception is that a lateral condyle elevating trochleoplasty will raise patellofemoral contact pressures and therefore initiate patellofemoral pain and cartilage degeneration 9 . The scientific evidence for this presumption is scarce and is only supported by one biomechanical study by Kuroda et al. who found raised pressures when the trochlea was elevated 6 to 10 mm in a cadaver model 15 . We have used this procedure for high grade trochlear dysplasia and in patients with trochlear dysplasia in which other procedures failed. We previously published short term results of this trochlear osteotomy in these difficult to treat patients 16 . We found no residual instability in 17 out of 19 knees and marked improvement in pain and functional scores in most patients at a mean follow-up of 51 months, and concluded that the results were satisfactory. Purpose and hypothesis In order to establish the long-term results of this procedure, we now re-evaluated these same patients to investigate the long-term outcomes of this lateral condyle elevating trochlear osteotomy. The aim of this study is to describe the clinical and radiological results of this surgical technique in patients at a minimum of 12 years post-operative with emphasis on (1) the clinical results with regard to functional scores and patellar stability and (2) the occurrence of osteoarthritis. We hypothesized that both the clinical and radiologic results would deteriorate over time.