Inclusion Criteria:  Patients who have undergone surgical treatment for recurrent patellar dislocation in Helse Vest. The investigators will include patients with reconstruction of the medial patella femoral ligament, trochleaplasty, tibial tubercle osteotomy, Insall or concomitant procedures.  Exclusion Criteria:  Unable to give written informed consent. Medial patellar dislocation. unable to understand written or spoken Norwegian. patients with other knee injuries.