To the Editor:

I read with interest the paper by Sillanpàà et al. [1] entitled “Ligament Reconstruction Versus Distal Realignment for Patellar Dislocation” published in the June 2008 issue. I congratulate the authors on their study, for the long-term followup and for the comparative study with distal realignment. However, I ask for clarification of two issues.

First, what are the indications for medial patellofemoral ligament reconstruction? Do you perform this surgical technique in all patients with patellar recurrent dislocation? Soft tissue abnormalities, such as lateral retinacular tightness, and some bony geometric knee parameters, such as the tibial tubercle-trochlear groove distance, patella alta, and trochlea dysplasia, can cause patellofemoral instability. Do you combine additional surgical procedures, such as a distal realignment and/or lateral retinacular release, when you find an abnormal Q angle (> 10°), or a great tibial tubercle-trochlear groove distance (> 20 mm), or a flattened trochlea? Trochlea dysplasia is thought to lead to excessive load on the medial patellofemoral ligament reconstruction, and tibial tuberosity transfer would, in theory, reduce the load to the reconstruction.

Second, I believe a surgical technique can prevent degenerative changes when it improves patellofemoral tracking and corrects some abnormal geometric parameters, such as congruence angle or lateral patellofemoral angle. Have you assessed postoperatively by radiographs or MRI whether the ligament reconstruction was able to correct the above-mentioned parameters, in comparison to the contralateral knee?