Reconstruction of the medial patellofemoral ligament with autologous grafts with or without osteotomy and transfer of tibial tuberosities.

It is expected that the subjective status of the knee will significantly improve after surgical stabilisation of the patellar joint. The change in subjective knee status will be measured with EQ-5D (European quality of life in 5 dimensions; min 0, max 100). Higher scores on the questioner mean a better outcome.

It is expected that the subjective status of the knee will significantly improve after surgical stabilisation of the patellar joint. The change in subjective knee status will be measured with KOOS (Knee osteoarthritis outcome score; min 0, max 100). Higher scores on the questioner mean a better outcome.

It is expected that the subjective status of the knee will significantly improve after surgical stabilisation of the patellar joint. The change in subjective knee status will be measured with Tegner activity scale (min 0, max 10). Higher scores on the scale mean a better outcome.

It is expected that the subjective status of the knee will significantly improve after surgical stabilisation of the patellar joint. The change in subjective knee status will be measured with Kujala questioner (min 0, max100). Higher score means a better outcome.

It is expected that the subjective status of the knee will significantly improve after surgical stabilisation of the patellar joint. The change in subjective knee status will be assessed with IKDC (International knee documentation committeemin; 0, max 100) questioner. Higher score on the questioner means a better outcome.

The height of the patella in the late post-operative period is not expected to differ from its position immediately after the procedure. The patellar height will be assessed with Caton-Deschamp index on standard lateral X-rays before surgery, immediately after surgery and at least six months after surgery. Reference values for normal patellar height are 0.8 - 1.2.