Comments on: "Recession wedge trochleoplasty as an additional procedure in the surgical treatment of patellar instability with major trochlear dysplasia: early results" by M. Thaunat, C. Bessiere, N. Pujol, P. Boisrenoult, P. Beaufils, published in Orthop Traumatol Surg Res 2011;97(8):833-45.

We read the article by Thaunat et al. using the recession edge trochleoplasty (RT) technique which was developed y our team, with interest. However, the indications for RT re different in the two articles. In our paper [1], RT is used n patellofemoral (PF) instability that has been stabilized, ut is still painful. In the article by Thaunat et al. RT is one f several procedures used to correct patellofemoral instaility with patellar dislocation or subluxation, procedures hich include 10 mm of frontal translation of the anteior tibial tuberosity (ATT) which is nearly always medial. ecause different procedures were associated, it was imposible for the authors to determine the exact role of RT in PF tabilization. We believe that the role of RT can be evaluated using a iagram which allowed us to study the effect of the postperative ATT.TG (anterior tibial tubercle trochlear groove istance) —trochlear angle (measured at 30◦ of flexion) on tabilization and postoperative pain after a mean followp of 8 years (5—14 years) in 63 cases of PF instability with t least one episode of patellar dislocation. Medial transer of the ATT was only performed in one case (associated ith resection of the lateral retinaculum) [2]. Values for ach knee were positioned on the diagram in relation to the ostoperative ATT.TG value — which is 6 mm less than that easured in extension [2] — and the trochlear angle (the rochlear prominence was not taken into account). Three reas were identified: one area of PF instability, one area f PF stability, pain free or nearly pain free, and one area f stablized but clearly painful PF. For each trochlear angle, F stability and lack of pain (or nearly) was obtained with he ATT.TG value in a range of 9 mm; the wider the trochlear ngle, the lower the ATT.TG values. An ATT.TG value that was bove this limit resulted in PF instability and a lower value