Introduction To investigate patient reported outcome measurement (PROM) reference data on a national cohort of patients between 15-19 years with prior patella dislocation and trochlear dysplasia.

Material and Methods All inhabitants in the Faroe Islands between 15 to 19 years were invited to answer an online survey. The survey included questions concerning prior patellar dislocation and the PROMs: Banff Patella Instability Instrument (BPII), Kujala score, Marx score and the EQ-5D-5L. Three cohorts were established: 1) The background cohort consisting of the participants with no prior patellar dislocation, 2) The patellar dislocation cohort consisting of all participants with prior patellar dislocation, 3) The trochlear dysplasia cohort consisting of participants with prior patellar dislocation who had trochlear dysplasia.

Results 3749 persons were contacted and 1119 (30%) completed the demographic survey and at least one PROM. 43 persons had prior surgery to the knee and were excluded. 102 reported prior patellar dislocation, of whom 57 were found to have trochlear dysplasia. All PROMs except the Marx score reflected worse quality of life and function after patellar dislocation compared with the background population, most pronounced in the BPII. The percentage of people experiencing problems in the EQ-5D-5L dimensions were increased for the patellar dislocation cohort and the trochlear dysplasia cohort inn all EQ-5D-5L domains, except for anxiety/depression.

Conclusion Young people (age 15-19) with prior patellar dislocation report seriously affected quality of life and function measured with the BPII, the Kujala, the EQ-5D-5L index values, and all EQ-5D-5L domains except anxiety/depression