Outcome of Arthroscopic Treatment for Femoroacetabular Impingement
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Open Access Protocol BMJ Open: first published as 10.1136/bmjopen-2015-008952 on 7 September 2015. Downloaded from The Horsens-Aarhus Femoro Acetabular Impingement (HAFAI) cohort: outcome of arthroscopic treatment for femoroacetabular impingement. Protocol for a prospective cohort study Signe Kierkegaard,1 Bent Lund,1 Ulrik Dalgas,2 Henrik Sørensen,2 Kjeld Søballe,3 Inger Mechlenburg3 To cite: Kierkegaard S, ABSTRACT Strengths and limitations of this study Lund B, Dalgas U, et al. The Introduction: During the past decade, it has Horsens-Aarhus Femoro become increasingly more common to offer hip ▪ Acetabular Impingement This prospective cohort study collects objectively arthroscopic surgery when treating people with (HAFAI) cohort: outcome of measured and self-reported data from patients arthroscopic treatment for femoroacetabular impingement (FAI). Nevertheless, undergoing arthroscopic hip surgery for femor- femoroacetabular the latest reviews conclude that it still remains to be oacetabular impingement. impingement. Protocol for a properly investigated how surgery affects the ▪ All patients are operated by the same experi- prospective cohort study. patients. Specifically, detailed information on the enced surgeon. BMJ Open 2015;5:e008952. functional, muscular and mechanical impact of ▪ Patient data are compared with an age-matched doi:10.1136/bmjopen-2015- surgery in larger groups is lacking. Furthermore, and gender-matched healthy reference group. 008952 the long-term outcome of the surgery is still to be ▪ For ethical reasons, it is not possible to evaluate investigated. the reference group radiologically. ▸ Prepublication history for Methods and analysis: In this prospective cohort this paper is available online. study, a total of 60 patients with FAI scheduled for To view these files please arthroscopic surgery will be followed and tested visit the journal online preoperatively, and again after 3, 6, 9 and 12 months. http://bmjopen.bmj.com/ (http://dx.doi.org/10.1136/ Assessment includes isokinetic dynamometry BACKGROUND bmjopen-2015-008952). evaluating hip flexion and extension; evaluation of Femoroacetabular impingement (FAI) is Received 1 June 2015 functional capacity in a three-dimensional motion caused by an abnormality in the acetabular Revised 27 July 2015 laboratory; pain assessment; self-reported function, shape or orientation (pincer-type), by a Accepted 17 August 2015 quality of life, expectation and satisfaction with the shape abnormality in the proximal femur surgery; recording of previous and present sporting (cam-type) or by a mix of the two condi- activities and accelerometry. In addition, data on tions.12FAI causes repeated minor damage surgical procedure, rehabilitation progress, adverse to the labrum and edge of the acetabulum, events and failure will be recorded. Patients will be on September 25, 2021 by guest. Protected copyright. compared with an age-matched and gender-matched labral tears and damage to the cartilage reference group of 30 persons with no hip, knee, lining of the hip joint resulting in pain from 3 ankle or back problems. Long-term follow-up of this the hip and groin region. The prevalence of 1Department of Orthopaedic cohort may evaluate possible reoperations and cam and/or pincer deformities has previ- Surgery, Horsens Hospital, development of hip osteoarthritis. Furthermore, ously been investigated in asymptomatic indi- Horsens, Denmark analysis on how subgroups respond to the treatment viduals with a mean age of 25 years, where a 2Section of Sports, could be performed together with identification of higher prevalence of cam deformity was seen Department of Public Health, possible “non-responders”. in athletes (37%) compared with the general Aarhus University, Aarhus, Ethics and dissemination: The study is population (23%).4 Asymptomatic pincer Denmark approved by the Central Denmark Region 3Department of Orthopaedic deformities were seen in 67% of the popula- Committee on Biomedical Research Ethics Surgery, Aarhus University tion, although they were less well defined in ( Journal No 1-10-72-239-14). The results from Hospital, Aarhus, Denmark the literature.4 It is unknown why only some this study will be presented at national and deformities become symptomatic, although Correspondence to international congresses and published in peer- Signe Kierkegaard; reviewed journals. the symptomatic deformities seem to be signekierkegaard@hotmail. Trial registration number: NCT02306525. linked to a combination of lifestyle factors 5 com and genetics. Kierkegaard S, et al. BMJ Open 2015;5:e008952. doi:10.1136/bmjopen-2015-008952 1 Open Access BMJ Open: first published as 10.1136/bmjopen-2015-008952 on 7 September 2015. Downloaded from FAI has been suggested to lead to early hip osteoarth- In contrast to patients with OA, patients with FAI ritis (OA).6 Severe cam-type FAI and reduced internal perform the same level of steps per day as seen in rotation especially strongly predispose to fast progression healthy controls.24 This is surprising given that many of OA,12and an investigation of symptoms and func- patients report hip pain during daily activities and when tions related to the specific subtypes of FAI and their doing sports.15 No studies were found to evaluate predisposition to development of OA is warranted. objectively measured physical activity levels besides Surgical treatment of FAI has been analysed in a stride-level activity, and no studies evaluated physical variety of studies of the open, combined and arthro- activity after surgery. Our clinical experience is that – scopic methods, respectively,7 11 demonstrating that there is large variation in patient symptoms, ranging surgery can reduce symptoms caused by impingement in from some patients who can hardly engage in daily activ- a short-term to mid-term perspective and may prevent ities to others who only experience problems during future damage to the hip joint. However, different surgi- high-impact physical performance. Consequently, it is cal techniques are used and only a few long-term studies difficult to plan physical performance tests fitting all on relevant outcomes after surgery exist.89Moreover, patients into one category.25 26 This suggests that the most recent reviews conclude that evidence is still patients should be stratified according to symptom sever- lacking to ensure that this type of surgery is effective for ity, FAI subtype, gender and age groups when analysed patients with FAI,12 and that knowledge on how surgery in future studies. impacts functional performance for the patients in the short-term and long-term perspective is lacking.13 Hence, with the rise in arthroscopic treatment of FAI AIM seen in the past decade,14 it is important to investigate The aim of this prospective cohort study is to evaluate the outcome of surgery further. biomechanics, muscle strength, physical activity and The pathology of FAI alters the intra-articular conditions patient-reported outcomes in patients with FAI before of the hip joint, making people report pain during and after arthroscopic surgery compared with a refer- motion.15 Accordingly, studies have shown that the hip ence group without hip problems. sagittal plane, frontal plane and transverse plane move- 1. Biomechanics: The aim is to investigate movement ments are altered during walking, stair climbing and squat- patterns for patients with FAI before and 1 year after ting for the patients.16 17 Hence, it is interesting to surgery compared with a reference group. It is investigate the total movement pattern of the lower hypothesised that: extremity compared with a reference group with the aim A. Patient gait and stair ascending and descending of giving clinicians a measure of the total gait quality. This kinematics described by the Gait Deviation Index may be described with the Gait Deviation Index,18 quanti- are lower than reference values preoperatively fying how much patients demonstrate altered kinematics and will increase 1 year postoperatively. http://bmjopen.bmj.com/ compared with reference persons. Different surgical tech- B. Hip flexion moment and hip extension angle are niques may restore hip sagittal plane movement during lower during the stance phase of gait and stair walking to reference values, though not during stair climb- descending for the patients. Hip flexion moment ing.16 Although kinematics are altered for the patients, and hip extension angle will increase 1 year after – study results are conflicting regarding kinetics.19 21 surgery compared with the preoperative period. Nevertheless, a larger study,21 which, in contrast to the C. Furthermore, the movement patterns of stepping, other studies, was powered for the statistical analysis, found sit-stand-sit and jumping will be explored. altered hip flexion moment and hip external rotation D. Subanalyses will be performed after stratification on September 25, 2021 by guest. Protected copyright. moment during walking. Further investigation on this of patients according to the type of FAI. matter is necessary in larger groups evaluating hip bio- 2. Muscle function: The aim is to investigate hip flexion mechanics, subgrouping patients into FAI subtypes based and extension muscle strength before and 1 year on radiography, before clear conclusions on the biomech- after surgery and its relation to pain during testing. It anical phenomena may be conducted.22 is hypothesised that: Of note, hip muscle function is also altered in patients A. Compared with reference values, isometric, con- with FAI. Specifically, Casartelli