Jordy van Sambeeck

Twelve year follow-up of a stand-alone lateral condyle elevating trochlear osteotomy 6 95 trochleoplasty 10. On the Iwano scale, they reported a grade 1 in 14 knees, grade 2 in 7, grade 3 in 2 and grade 4 in 1 knee. Ntagiopoulos et al 22 remarkably found no radiological osteoarthritis at all at a mean of 7 years follow up after their sulcus deepening trochleoplasty. In contrast, Rouanet et al found grade 2 or more radiological osteoarthritis on the Iwano scale in 20 out of 34 knees at 15 years follow up in their series of a sulcus deepening trochleoplasty and 7 knees were already converted to a total knee arthroplasty after the same procedure 31. General perception on the Albee or lateral condyle elevating procedures is that by raising the lateral condyle, pressures in the patellofemoral joint increase and thus would lead to patellofemoral osteoarthritis. This idea is supported by a study by Kuroda et al who found increased contact pressures in a cadaver model after the lateral trochlea was raised 15 . In contrast, other authors have reported that a larger sulcus angle, i.e. a flatter trochlea, especially in the proximal trochlea, leads to increased cartilage loss 32-34 . Raising the lateral condyle, and thus restoring the normal inclination of the lateral wall of the trochlea, would then act to preserve the cartilage of the patellofemoral joint instead of leading to an increase in osteoarthritis. Based on our results and the reported results from other studies, we must conclude that a lateral condyle elevating trochlear osteotomy leads to an increase in patellofemoral osteoarthritis, but it does not exceed the amount of osteoarthritis reported in other types of trochleoplasties. The major strength of this study is its long term follow-up and thorough evaluation at final follow up with physical examination and radiographs. Due to the nature of this procedure, it is indicated in relatively few cases of patellar instability. In this study only 19 knees were included in the original series of which 15 were available for final follow up. Therefore 4 out of 19 knees (21.1%, including the one patient who could not be evaluated due to the conversion to a patellofemoral arthroplasty) were not available for follow up, diminishing the power of the study. Additionally, no Kujala score was performed pre-operatively, whichmakes a proper comparison to other studies difficult as not pre- and post-operative difference could be determined. Conclusion Based on this study, we must conclude that a single lateral condyle elevating trochlear osteotomy leads to a high amount of residual patellofemoral instability when compared to studies in which trochleoplasty was combined with other realignment procedures. We therefore advice not to use it as a stand-alone procedure but always perform a simultaneous medial patellofemoral ligament reconstruction. After 12 years follow-up we did not find that the development of patellofemoral osteoarthritis exceeded the findings from other case series of trochleoplasties.