Combined patellofemoral arthroplasty and medial patellofemoral ligament reconstruction for chronic patellar instability with trochlear dysplasia: a report of two cases.

Deepening trochleoplasty combined with other patella stabilization procedures is often performed to correct patellar instability with trochlear dysplasia. However, various complications following trochleoplasty including patellofemoral osteoarthritis and anterior knee pain can be negative factors affecting the clinical results. Here, we describe two cases of chronic patellar instability with trochlear dysplasia on whom we performed patellofemoral arthroplasty (PFA), instead of trochleoplasty, in conjunction with medial patellofemoral ligament (MPFL) reconstruction. In both cases, PFA, acting as metallic trochleoplasty, improved the congruency of patellofemoral joint, and achieved good clinical results for up to 3 years postoperatively without recurrent patellar instability. This procedure could be considered as one option for cases of chronic patellar instability with trochlear dysplasia.