Vol.:(0123456789) 1 3 Knee Surgery, Sports Traumatology, Arthroscopy https://doi.org/10.1007/s00167-019-05503-5 HIP Despite patient‑reported outcomes improve, patients with femoroacetabular impingement syndrome do not increase their objectively measured sport and physical activity level 1 year after hip arthroscopic surgery. Results from the HAFAI cohort Signe Kierkegaard 1  · Ulrik Dalgas 2  · Bent Lund 1  · Matthijs Lipperts 3  · Kjeld Søballe 4  · Inger Mechlenburg 4 Received: 30 November 2018 / Accepted: 1 April 2019 © European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2019 Abstract Purpose Patients with femoroacetabular impingement syndrome (FAIS) are young and middle-aged persons living physi- cally active lives including sports activities. However, measurements of the physical activity level before and after hip arthroscopic surgery in patients with FAIS using both self-reported and objective accelerometer-based measures are lacking. Furthermore, comparing patients with a reference group of persons reporting no hip problems and conducting subgroup analyses investigating changes in physical activity level and self-reported outcomes according to pre-surgery activity level may further highlight the activity pattern for patients. Methods Sixty patients with FAIS eligible for hip arthroscopic surgery were consecutively included in a prospective cohort study (HAFAI cohort) together with 30 reference persons reporting no hip problems. Participants completed the Copenhagen Hip and Groin Outcome Score (HAGOS) together with questions regarding their sports activities. Furthermore, participants wore a three-axial accelerometer for fve consecutive days during waking hours. The accelerometer-based data were analysed and presented as total activity and type, frequency and duration of activities. Results Patients experienced signifcant and clinically relevant changes in all HAGOS scores. 88% of patients participated in some kind of sports activity 1 year after surgery. Overall, objectively measured physical activity did not change from before to 1 year after surgery. However, subgroup analyses of the most sedentary patients preoperatively revealed signifcant changes towards a more active pattern. Compared to reference persons, patients performed less bicycling and running. Conclusion Despite clinically relevant changes in self-reported outcomes, patients did not increase their overall physical activity level 1 year after surgery. Physical activity levels were lower in patients than in the reference group and patients continued bicycling and running less compared with the reference group. Level of evidence II. Keywords Femoroacetabular impingement · Physical activity · Hip arthroscopy · Sport · Participation Introduction Femoroacetabular impingement syndrome (FAIS) involves pain and decreased hip function predominantly afecting young and middle-aged persons [3]. The patient group with FAIS consists of both sedentary persons and athletes. Patients gain improvements in self-reported outcomes after hip arthroscopy regardless of their activity level [15]. How- ever, the majority of patients do not reach reference levels of hip function when assessed by questionnaires at any time point after surgery [8]. The latest reviews conclude that objective data describing physical function are lacking in * Signe Kierkegaard signekierkegaard@hotmail.com 1 H-Hip, Department of Physio and Occupational Therapy and Orthopedic Surgery, Horsens Hospital, Sundvej 30, 8700 Horsens, Denmark 2 Department of Public Health, Section for Sport, Aarhus University, Aarhus, Denmark 3 Department of Medical Information, Communication and Technology, St. Anna Hospital, Geldrop, The Netherlands 4 Department of Orthopedic Surgery, Aarhus University Hospital, Aarhus, Denmark