The Danish Hip Arthroscopy Registry: Registration Completeness and Patient Characteristics Between Responders and Non-Responders

PURPOSE: To report completeness of registered surgeries in the Danish hip arthroscopy registry (DHAR) and proportion of patients completing patient-reported outcome measures (PROMs) prior to surgery and at 1-year follow-up. PATIENTS AND METHODS: Completeness was determined as the number of surgeries registered in DHAR in comparison with the number of surgeries registered in the Danish National Patient Registry database (DNPR). The number of patients self-reporting pre-surgical PROMs was compared to the total number of surgeries registered in DHAR. Further, we evaluated potential differences in baseline characteristics between the groups of responders and non-responders at 1-year follow-up. Patient characteristics included age, sex, activity levels measured by the hip sports activity scale (HSAS), and PROMs (Copenhagen Hip and Groin Outcome Score, EQ-5D-3L and general hip status). Age was stratified in three groups (<25, 25–39, ≥40). RESULTS: From February 2012 to September 2018, 5565 arthroscopic hip surgeries were registered in DNPR, and 4937 were registered in DHAR (89%). The yearly rate of registrations in DHAR compared to DNPR increased from 77% in 2012 to 85% in 2018 and peaking in 2015 at 94%. A total of 3294 DHAR-registered patients (67%) had self-reported their pre-surgical outcome scores, and of those, 2886 (58%) completed PROMs at 1-year follow-up. More males (45 vs 41%, p = 0.002) and individuals younger than 25 years of age (24% vs 18%, p<0.001) had not completed follow-up questionnaire. The PROM baseline scores of the responders at follow-up did not differ from the non-responders. CONCLUSION: The proportion of arthroscopic hip surgeries registered in the Danish Hip Arthroscopy Registry and the proportion of self-reporting PROM scores have increased to acceptable levels, whereas the proportion of patients with follow-up data is comparably low. For further quality improvement, more attention should be given to patients completing PROMs, focusing on younger males and follow-up PROMs.