Fifty-seven percent of athletes returned to preinjury sport at their preinjury level. This is considerably lower than a previously reported return to sport rate of 87% and may reflect that the present study used a clear and strict definition of return to sport. Of note, only one-third of athletes who returned to preinjury sport at preinjury level reported their sports performance to be optimal, corresponding to 16.9% of the study sample. Better self-reported hip and groin function was observed in athletes who were playing preinjury sport at preinjury level compared with athletes who were not.

Statistically and clinically relevant improvements in HAGOS and mHHS results after hip arthroscopy and rehabilitation can be seen at 3 months and up to 1 year. However, specific HAGOS subscales suggest that a patient's ability to function and participate in sport and physical activity is still markedly reduced 1 year after surgery. Furthermore, the majority of patients undergoing hip arthroscopy cannot expect to reach the level of the healthy population on self-reported pain and function within the first year after surgery.

The Danish Hip Arthroscopy Registry (DHAR) was initiated in January 2012 as a web-based prospective registry. The purpose of this study was to evaluate and report the first registry based outcome data of a national population with radiological and clinical femoroacetabular impingement (FAI) undergoing hip arthroscopic treatment. Our primary hypothesis was that patients undergoing hip arthroscopy would improve significantly in pain, quality of life and sports related outcome measurements in Patient Related Outcome Measures (PROM). Peri-operative data and Patient Reported Outcome Measures (PROM) data from DHAR between January 2012 and November 2015 were extracted. Radiological pincer-type FAI was defined as LCE > 35° and cam FAI as alpha-angle > 55°. These data were combined with FAI surgical data such as osteochondroplasty and labral repair or resection. PROMs consisting of HAGOS, EQ-5 D, HSAS and NRS pain scores were submitted online by the patients pre-operatively and at 1 and 2-years follow-up. 2054 FAI procedures in 1835 patients were included in this study (219 patients had bilateral procedures performed). HAGOS demonstrated significant improvement in all subscales at follow up. EQ-5 D demonstrated improvement after 1 and 2 years from 0.66 pre-op to 0.78 at 2 years. HSAS improved significantly from 2.5 to 3.3. Pain score data demonstrated improvement in NRS-rest 39 to 17 and NRS Walk 49 to 22 at follow-up. We conclude that patients with FAI undergoing hip arthroscopy experience improvement in pain, quality of life and also in function and sports related outcome measures during the first 2 years after surgery.

Danish Hip Arthroscopy Registry (DHAR) was initiated in 2012 as a web-based prospective registry. The purpose of this study was to evaluate and report the epidemiologic and perioperative data of the first 2000 procedures in a Danish hip arthroscopy population and to describe the development of DHAR. We describe the use of various Patient Related Outcome Measures related to non-arthritic hip patients. The 2000 procedures consisted of 56% females and 44% males. Mean age 37.5 years, mean surgical time was 86.5 min and mean traction time 50.5 min. The most frequently performed procedure was CAM and Pincer resection in 93.5% of the cases. Labral refixation or repair was done in 70.3% of the cases. The most common type of acetabular chondral damage was grade II lesions (36.6%). Grade III and IV changes were seen in 36.1% of the cases. The preoperative iHOT12 was 45 (mean) based on all 12 items. EQ-5D was 0.65 and HAGOS sub-scores were 51 (pain), 49 (symptoms), 53 (ADL), 35 (sport), 20 (physical activity) and 29, respectively. We conclude that patients undergoing hip arthroscopy report considerable pain, loss of function, reduced level of activity and reduced quality-of-life prior to surgery. The problems with development and maintaining a large clinical registry are described and further studies are needed to validate data completeness. We consider the development of a national clinical registry for hip arthroscopy as a successful way of developing and maintaining a valuable clinical and scientific tool.