[Repair of local cartilage defects in the patellofemoral joint]

Cartilage defects of the patellofemoral joint represent different entities. Results of patellofemoral cartilage repair are often variable. Concomitant pathologies, such as malalignment and instability are frequent. Currently no common treatment concept exists. Improvement of patellofemoral biomechanics, e.g. tubercle transfer, results in better outcome independent of the cartilage repair technique used. In patellofemoral instability reconstruction of the medial patellofemoral ligament (MPFL) has recently become a focus of interest. Microfracturing and osteochondral cylinder transfer/mosaicplasty are recommended for smaller defects, while comparative studies have shown advantages for autologous chondrocyte implantation (ACI) in defects larger than 4 cm². In our study patients with patellofemoral scaffold ACI (MACI®), better Lysholm scores were seen with isolated trochlea defects rather than patella defects or bipolar lesions. While trochlea defects can be effectively addressed, treatment of bipolar patellofemoral defects by scaffold ACI cannot generally be recommended. Follow-up treatment of the patellofemoral joint is more time and cost-consuming than other defect localizations. For the development of therapeutic algorithms further well-defined large randomized studies are necessary.