Current trends in sport and exercise hip conditions: Intra-articular and extra-articular hip pain, with detailed focus on femoroacetabular impingement (FAI) syndrome

First-line treatment for femoroacetabular impingement syndrome and hip-related quality of life: study protocol for a multicentre randomised controlled trial comparing a 6-month supervised strength exercise intervention to usual care (the Better Hip Trial)

INTRODUCTION

Femoroacetabular impingement syndrome (FAIS) is a motion-related and position-related clinical condition of the hip associated with pain, reduced physical function and hip-related quality of life (QoL). Interestingly, higher maximal muscle strength is associated with less pain, better physical function and improved QoL in people with FAIS. Furthermore, preliminary evidence suggests that a proportion of patients with FAIS respond positively to strength exercise as first-line treatment. Nonetheless, there is little evidence supporting a specific exercise intervention offered as a first-line treatment. We will conduct a randomised controlled trial investigating the clinical effectiveness and cost-effectiveness of a 6-month strength exercise intervention compared with usual care as first-line treatment in patients with FAIS.

METHODS AND ANALYSIS

This is a multicentre randomised controlled trial that will be conducted at hospitals and physiotherapy clinics across Denmark and Australia. A total of 120 patients with FAIS will be randomised (1:1) to 6 months of supervised strength exercise or usual care. The primary outcome is the change in hip-related QoL measured using the International Hip and Outcome Tool 33 (iHOT-33) from baseline to the end of intervention. A health economic evaluation will be conducted from a societal and healthcare perspective based on the data collection over a 12-month period starting at baseline. The analysis will calculate incremental cost-effectiveness ratios using quality-adjusted life-years and iHOT-33 scores while estimating costs using microcosting and cost questionnaires. Secondary outcomes include objectively measured physical function at baseline and after 6 months and patient-reported outcomes measured at baseline, 3-month, 6-month and 12-month follow-up.

ETHICS AND DISSEMINATION

The trial has been approved by the Committee on Health Research Ethics in the Central Denmark Region (journal no 1-10-72-45-23) and La Trobe University Human Ethics Committee (HEC24042) and is registered at the Central Denmark Region List of Research Projects (journal no 1-16-02-115-23). Informed consent will be obtained from each participant before randomisation. Results will be published in international peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

NCT05927935.

Patient-Perceived Outcomes Improve Faster Than Hip Strength in Recovery After Surgical Correction for Symptomatic Femoroacetabular Impingement

Background: Patients with symptomatic femoroacetabular impingement (FAI) have hip strength deficits, instability, and increased risk for concomitant injury. While surgical intervention is an effective method of treatment for FAI, more information is needed about the recovery process. Purposes: We sought to understand how patients with FAI recover from surgical correction in the short term. Do patients' perceptions of improvement correspond with measured improvements in hip strength? Methods: We conducted a prospective cohort study of 17 patients (11 male, age range: 16-38 years) who were diagnosed with symptomatic FAI at a single surgeon's practice. Hip strength (flexion, extension, and abduction) was measured preoperatively and at 14, 26, and 52 weeks postoperatively. Patient-reported outcomes using the modified Harris Hip Score (mHHS) and Hip Outcome Osteoarthritis Score (HOOS) subscales were measured at the same time points and at 2 weeks postoperatively. Results: Compared with preoperative values, there was a significant increase in postoperative values at 26 and 52 weeks in normalized isokinetic hip extension (29% and 38%, respectively) and normalized hip abduction (48% and 55%, respectively). No differences in strength were observed at 14 weeks. Modified Harris Hip Score and all HOOS subscales were decreased by 2 weeks postoperatively, and by 14 weeks mHHS improved by 21%, and HOOS subscales improved as well (activities of daily living by 18%, pain by 34%, quality of life by 69%, sport and recreation by 36%, and symptoms by 28%). Conclusion: We observed that patient-reported outcomes including symptoms, function, and satisfaction improved at 14 weeks, while objective measures of hip strength improved at 26 weeks following surgical correction of FAI. More rigorous study is indicated.

Exercise in patients with acetabular retroversion and excessive anterior pelvic tilt: A feasibility and intervention study

BACKGROUND

Acetabular retroversion is associated with femoroacetabular impingement syndrome (FAIS). Anterior pelvic tilt enhances risk of FAIS.

OBJECTIVES

To investigate feasibility and change in patient-reported symptoms of a home-based exercise intervention in patients with acetabular retroversion and excessive anterior pelvic tilt, in comparison with a prior control period.

DESIGN

Prospective intervention study.

METHODS

Patients (18-40 years) not eligible for surgery, with radiographic signs of acetabular retroversion and excessive anterior pelvic tilt were recruited. An 8-week control period was followed by an 8-week training period. The home-based intervention consisted of education and exercises for core stability, muscle strengthening and stretching for reducing anterior pelvic tilt. Feasibility assessments were dropout (≤10%), adherence (≥75% of sessions), exercise-related pain, and adverse events. Primary outcome was change in the Copenhagen Hip and Groin Outcome Score (HAGOS) pain-subscale. Pelvic tilt was measured by EOS scanning.

RESULTS

Forty-two patients (93% female, mean age 22.2 ± 4.2 years) were included. Dropout rate was 7% and satisfactory adherence was demonstrated by 85%. Exercise-related pain and adverse events were acceptable. Between-period mean change score for HAGOS-PAIN was 5.2 points (95% CI: -0.3-10.6) and -1.6° (95% CI: -3.9-0.7) of anterior pelvic tilt. Patients responding positively (≥10 points) (n = 10, 26%), had pre-exercise moderate pain (HAGOS-PAIN 47.5-70 points).

CONCLUSIONS

Current exercise intervention was feasible. However, we found no clinically relevant changes in self-reported hip-related pain or anterior pelvic tilt. Post hoc responder analysis revealed that patients with moderate pain at baseline might benefit from this exercise.

Effect of Sacroiliac Joint Pain on Outcomes in Patients Undergoing Hip Arthroscopy for the Treatment of Femoroacetabular Impingement Syndrome: A Matched Comparative Cohort Analysis at Minimum 2-Year Follow-up

BACKGROUND

Patients with femoroacetabular impingement syndrome (FAIS) may frequently have co-existing sacroiliac joint (SIJ) pain. It is known that patients with lower back pain undergoing total hip arthroplasty (THA) have inferior outcomes; however, it is unclear what the effect of SIJ pain is on outcomes after hip arthroscopy.

PURPOSE

To determine whether patients undergoing hip arthroscopy with SIJ pain either subjectively or on physical examination achieve similar postoperative improvement in patient-reported outcomes (PROs) compared with patients without SIJ pain at 2-year follow-up.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients with a minimum 2-year follow-up who underwent primary hip arthroscopy for FAIS with SIJ pain were matched in a 1:2 ratio to controls without SIJ pain. Baseline demographics, as well as postoperative PROs and rates of achievement of the minimal clinically important difference (MCID) or Patient Acceptable Symptom State (PASS) at 2-year follow-up were compared between the 2 groups.

RESULTS

A total of 73 patients (75 hips) with SIJ pain were matched to 150 control patients (150 hips) without SIJ pain. Both groups demonstrated statistically significant improvement in all PROs at 2 years (P < .05 for all). Patients with SIJ pain had significantly lower postoperative PRO scores for the Hip Outcome Score-Activities of Daily Living (HOS-ADL) (SIJ pain: 80.4 ± 22.4 vs no SIJ pain: 88.0 ± 15.1; P = .006), modified Harris Hip Score (mHHS) (SIJ pain: 73.2 ± 22.8 vs no SIJ pain: 80.0 ± 17.3; P < .001), and International Hip Outcome Tool-12 questionnaire (iHOT-12) (SIJ pain: 61.7 ± 25.9 vs no SIJ pain: 73.7 ± 23.7; P = .008). There were no statistically significant differences in improvement (delta) in PRO scores between the 2 groups (P > .05 for all). The SIJ pain group had significantly lower achievement of MCID for the HOS-ADL (SIJ pain: 65.2% vs no SIJ pain: 80.5%; P = .044) but not HOS-SS, mHHS, or iHOT-12 (P > .05 for all). The SIJ pain group had significantly lower achievement of PASS for the mHHS (SIJ pain: 27.5% vs no SIJ pain: 45.3%; P = .030) and iHOT-12 (SIJ pain: 31.0% vs no SIJ pain: 56.0%; P = .010) but not the HOS-ADL and HOS-SS (P > .05 for both). Only 4.1% of patients with SIJ pain and 2.4% of controls required revision surgery or converted to THA at the time of final follow-up (P = .69).

CONCLUSION

Patients with FAIS and SIJ pain on history or physical examination experience significant improvement in PROs at 2 years after hip arthroscopy. However, they may be less likely to achieve the MCID or PASS and have significantly lower postoperative PROs compared with a matched cohort of patients without SIJ pain. Overall rates of revision and conversion to THA were similarly low in both groups.

A Novel Model of Hip Femoroacetabular Impingement in Immature Rabbits Reproduces the Distinctive Head-Neck Cam Deformity

BACKGROUND

Femoroacetabular impingement (FAI) is a leading cause of hip pain in young adults and often leads to degenerative osteoarthritis (OA). A small animal model of hip deformities is crucial for unraveling the pathophysiology of hip OA secondary to FAI.

PURPOSES

To (1) characterize a new minimally invasive surgical technique to create a proximal femoral head-neck deformity in a skeletally immature rabbit model and (2) document the effect of an injury to the medial proximal femoral epiphysis on head-neck morphology at 28 days after the injury.

STUDY DESIGN

Controlled laboratory study.

METHODS

Six-week-old New Zealand White rabbits (n = 10) were subjected to right hip surgery, with the left hip used as a control. An epiphyseal injury in the medial femoral head was created using a 1.6-mm drill. Hips were harvested bilaterally at 28 days after surgery. Alpha and epiphyseal shaft angles were measured on radiographs. Alpha angles at the 1- and 3-o'clock positions were measured on the oblique axial plane of micro-computed tomography images. Bone bar formation secondary to growth plate injuries was confirmed using alcian blue hematoxylin staining.

RESULTS

All hips in the study group showed a varus-type head-neck deformity, with lower epiphyseal shaft angles on anteroposterior radiographs versus those in the control group (133°± 8° vs 142°± 5°, respectively; P = .022) and higher epiphyseal shaft angles on lateral radiographs (27°± 12° vs 10°± 7°, respectively; P < .001). The mean alpha angles in the study group were higher at both the 1- (103°± 14° vs 46°± 7°, respectively; P < .002) and 3-o'clock (99°± 18° vs 35°± 11°, respectively; P < .002) positions than those in the control group. Alcian blue hematoxylin staining of all hips in the study group indicated that the injured physis developed a bony bar, leading to growth plate arrest on the medial femoral head.

CONCLUSION

The proposed model led to growth arrest at the proximal femoral physis, resulting in a femoral head-neck deformity similar to human FAI.

CLINICAL RELEVANCE

Our novel small animal model of a femoral head-neck deformity is a potential platform for research into the basic mechanisms of FAI disease progression and the development of disease-modifying therapies.

Association between femoroacetabular impingement syndrome and limited lateral hip rotation in young athletes: A case-control study

PURPOSE

Hip pain is very common in athletes. One of the main disorders causing hip pain is femoroacetabular impingement syndrome. This study aimed to identify a new etiological risk factor for femoroacetabular impingement in the hip.

METHODS

This case-control study included 88 young athletes, 34 with pains in the hip (supposedly with femoroacetabular impingement) and 54 controls. Femoroacetabular impingement was diagnosed with a flexion, adduction, internal, and rotation test and a particular type of hip pain during sports activities. The medial (internal) and lateral (external) hip ranges of rotation have been measured with an inclinometer. The data were analyzed using a t-test, the Wilcoxon test, the Mann-Whitney U test, and logistic regression.

RESULTS

There is a statistically significant difference in the external hip rotation range between the athletes with hip pain and controls. Logistic regression analysis showed that external hip range of motion is significantly associated with femoroacetabular impingement.

CONCLUSION

Limited external hip range of motion was found to be significantly associated with the diagnosis of femoroacetabular impingement in young athletes. A biomechanical explanation of the hypothesis that limited external hip rotation can predict femoroacetabular impingement is given. Based on our results, the hip's lateral range of motion screening can be advised within the regular screening of young athletes. Kinesiotherapeutic procedures for stretching the muscles of the medial hip rotors can be advised to prevent the lateral hip rotation restriction and lower the risk of femoroacetabular impingement in case the limited rotation is due to muscular restriction.

LEVEL OF EVIDENCE

level III-case-control study.

Correlação entre intensidade da dor e incapacidade com as lesões intra-articulares em pacientes com síndrome do impacto femoroacetabular

Objective  To correlate radiographic alterations and lesions in intra-articular structures of the acetabulum with the intensity of pain and disability of patients diagnosed with femoroacetabular impingement syndrome.

Methods  A retrospective analysis of the preoperative data of 182 patients (190 hips) was performed. Clinical variables such as age, gender, the practice of physical activity, and radiographic variables, such as the Wiberg and alpha angles, were evaluated. Through an intraoperative video, the extent of the chondral and labial lesions was evaluated considering the clock-face method, the degree of joint involvement by the Outerbridge classification, and the presence of wave lesions. The variables were analyzed by linear regression, with the intensity of the pain assessed by the Visual Analog Scale (VAS), and functional disability measured by the Modified Harris Hip Score (mHHS).

Results  The mean age of the patients was of 38.5 ±  9.6 years, the mean intensity of the pain was of 7.8 ± 1.6, and the mean mHHS score was of 56.3 ±  12.7. In total, 61% of the sample were classified as Outerbridge III or IV, and 12.6% had wave lesions. There was a correlation between the male gender (r = 0.497) and lower intensity of the pain, and a correlation of age (r = -0.27), the male gender (r = 8.419) and physical activity with higher functional scores on the mHHS (r = 4.729).

Conclusion  There was no correlation of the radiographic and arthroscopic parameters of the present study and the intensity of pain and the disability of the patients. The male gender is related to lower intensity of pain, and higher functional ability is related to the male gender, lower age, and the practice of physical activity.

Level of Evidence IV.

Long-standing groin pain syndrome in athletic women: a multidisciplinary assessment in keeping with the italian consensus agreement

BACKGROUND

Long-standing groin pain syndrome (LSGPS) is a form of groin pain syndrome in which the cohort of symptoms reported by patients is experienced for a long period, typically for over 12 weeks, and is recalcitrant to any conservative therapy. The aim of this prospective epidemiological study was to describe the clinical causes of LSGPS in 37 female athletic subjects in Italy through the Groin Pain Syndrome Italian Consensus Conference on terminology, clinical evaluation and imaging assessment in groin pain in athletes classification and guidelines.

METHODS

Thirty-seven female athletes affected by LSGPS were evaluated following the guidelines issued by the Groin Pain Syndrome Italian Consensus Conference on terminology, clinical evaluation and imaging assessment of groin pain in athletes.

RESULTS

In the considered population, each patient presented only one pathological cause for LSGPS. The most frequent aetiologies were inguinal pathologies (54.05% of the cases), acetabular labrum tear (18.92%) and pelvic floor disorders (8.11%). Adductor tendinopathy represented only 2.70% of cases.

CONCLUSIONS

Female athletic patients affected by LSGPS show a similar incidence of inguinal and hip pathologies as in male populations. However, these clinical situations do not seem to be associated in women unlike in the male population. This difference is probably due to particular anatomical differences related to gender. For this reason, women affected by LSGPS represent an important subset of patients. Moreover, adductor tendinopathy is probably overrated as an etiopathogenetic source of LSGPS in women.

Open MRI assessment of anterior femoroacetabular clearance in active and passive impingement-provoking postures

Aims

Cam and pincer morphologies are potential precursors to hip osteoarthritis and important contributors to non-arthritic hip pain. However, only some hips with these pathomorphologies develop symptoms and joint degeneration, and it is not clear why. Anterior impingement between the femoral head-neck contour and acetabular rim in positions of hip flexion combined with rotation is a proposed pathomechanism in these hips, but this has not been studied in active postures. Our aim was to assess the anterior impingement pathomechanism in both active and passive postures with high hip flexion that are thought to provoke impingement.

Methods

We recruited nine participants with cam and/or pincer morphologies and with pain, 13 participants with cam and/or pincer morphologies and without pain, and 11 controls from a population-based cohort. We scanned hips in active squatting and passive sitting flexion, adduction, and internal rotation using open MRI and quantified anterior femoroacetabular clearance using the β angle.

Results

In squatting, we found significantly decreased anterior femoroacetabular clearance in painful hips with cam and/or pincer morphologies (mean -11.3° (SD 19.2°)) compared to pain-free hips with cam and/or pincer morphologies (mean 8.5° (SD 14.6°); p = 0.022) and controls (mean 18.6° (SD 8.5°); p < 0.001). In sitting flexion, adduction, and internal rotation, we found significantly decreased anterior clearance in both painful (mean -15.2° (SD 15.3°); p = 0.002) and painfree hips (mean -4.7° (SD 13°); p = 0.010) with cam and/pincer morphologies compared to the controls (mean 7.1° (SD 5.9°)).

Conclusion

Our results support the anterior femoroacetabular impingement pathomechanism in hips with cam and/or pincer morphologies and highlight the effect of posture on this pathomechanism.

Cite this article: Bone Jt Open 2021;2(11):988–996.

Open MRI validation of a hip model driven with subject-specific motion capture data in predicting anterior femoroacetabular clearance

BACKGROUND

Cam and/or pincer morphologies (CPM) are potential precursors to hip osteoarthritis (OA) and important contributors to non-arthritic hip pain. However, only some CPM hips develop OA and/or pain, and it is not clear why. Anterior impingement between the femoral head/neck contour and acetabular rim during motion is a proposed pathomechanism. Understanding how activity and deformity combine to produce impingement may shed light on the causes of hip degeneration/pain. The objective of this study was to determine the accuracy of a subject-specific hip model driven by subject-specific motion data in predicting anterior impingement.

METHODS

We recruited 22 participants with CPM (both with and without pain) and 11 controls. We collected subject-specific 3D kinematics during squatting and sitting flexion, adduction, and internal rotation (FADIR) (an active and a passive maneuver, respectively, proposed to provoke impingement). We then developed 3D subject-specific hip models from supine 3T hip MRI scans that predicted the beta angle (a measure of anterior femoroacetabular clearance) for each frame of acquired kinematics. To assess the accuracy of these predictions, we measured the beta angle directly in the final position of squatting and sitting FADIR using open MRI scans. We selected the frame of motion data matching the static imaged posture using the least-squares error in hip angles. Model accuracy for each subject was calculated as the absolute error between the open MRI measure of beta and the model prediction of beta at the matched time frame. To make the final model accuracy independent of goodness of match between open MRI position and motion data, a threshold was set for least-squares error in hip angles, and only participants that were below this threshold were considered in the final model accuracy calculation, yielding results from 10 participants for squatting and 7 participants for sitting FADIR.

RESULTS

For squatting and sitting FADIR, we found an accuracy of 1.1°(0.8°) and 1.3°(mean (SD), and root mean squared error, respectively) and 0.5°(0.3°) and 0.6°, respectively.

CONCLUSION

This subject-specific hip model predicts anterior femoroacetabular clearance with an accuracy of about 1°, making it useful to predict anterior impingement during activities measured with motion analysis.

Physical impairments in longstanding hip and groin pain: Cross-sectional comparison of patients with hip-related pain or non-hip-related groin pain and healthy controls

OBJECTIVES

To compare physical impairments between patients with hip-related pain and those with non-hip-related groin pain, and to compare both patient groups with healthy controls.

DESIGN

Cross-sectional.

PARTICIPANTS

Eighty-one hip and groin pain patients were consecutively included and categorized into having hip-related pain or non-hip-related groin pain. Twenty-eight healthy controls were recruited.

SETTINGS

Tertiary care.

MAIN OUTCOME MEASURES

All participants performed physical impairment testing including hip ROM, muscle function, and functional tasks. An analysis of covariates was used for analysis between patients groups and controls.

RESULTS

Patients with hip-related pain showed reduced hip ROM in internal rotation compared to patients with non-hip-related groin pain and controls (p ≤ 0.026, d -0.65; -0.97). No differences in muscle function or performance in functional tasks were observed between patients with hip-related pain and those with non-hip-related groin pain (p ≥ 0.136, d 0.00; 0.68). Both patient groups had worse muscle function and worse performance in functional tasks compared to controls (p ≤ 0.048, d -0.67; -1.83).

CONCLUSIONS

Both patients with and without hip-related pain had worse muscle function and worse performance in functional tasks compared to matched controls but no differences were observed between the patient groups. Only patients with hip-related pain had reduced ROM in internal rotation.

Hip muscle activity in male football players with hip-related pain; a comparison with asymptomatic controls during walking

OBJECTIVES

Compare muscle activity between male football players with and without hip-related pain. Morphological and intra-articular features of hip-related pain are proposed pre-cursors to hip osteoarthritis. Altered muscle activity is a feature of severe hip osteoarthritis, but it is not known whether differences exist earlier in the pathological spectrum.

DESIGN

Cross-sectional; SETTING: University laboratory; PARTICIPANTS: Forty-two male football players with hip-related pain; and 19 asymptomatic controls.

MAIN OUTCOME MEASURES

Hip muscle activity (Gluteus maximus, gluteus medius, tensor facia latae, adductor longus and rectus femoris) was recorded during walking using surface electromyography (EMG).

RESULTS

Men with hip-related pain had sustained rectus femoris activity prior to toe-off (47-51% of the gait cycle) (p = 0.01, ES = 0.51) unlike controls who had reduced activity. In men with severe hip-related pain, gluteus maximus EMG was sustained into mid-stance (12-20% of the gait cycle) (F = 6.15, p < 0.01) compared to controls.

CONCLUSIONS

Differences in rectus femoris and gluteus maximus activity were identified between male footballers with and without hip-related pain. The pattern of gluteus maximus EMG relative to peak, approaching mid-stance in severe hip-related pain, is consistent with observations in severe hip osteoarthritis. This supports the hypothesis that symptom severity may influence muscle activity across the spectrum of hip degeneration.

Hip Pain: Imaging of Intra-articular and Extra-articular Causes

Hip pain is a common and complex clinical entity. The causes of hip injuries in athletes are many and diverse, requiring efficient, accurate diagnosis for proper management. Imaging is an important step in the clinical evaluation of hip pain, and familiarity with multiple imaging modalities as well as characteristic imaging findings is a helpful tool for sports medicine clinicians. This article discusses imaging recommendations and gives imaging examples of common causes of intra-articular and extra-articular hip pain including femoroacetabular impingement, labral tears, cartilage defects, ligamentum teres injuries, snapping hip syndrome, femoral stress injuries, thigh splints, athletic pubalgia, avulsion injuries, and hip dislocation.

The Management between Comorbidities and Pain Level with Physical Activity in Individuals with Hip Osteoarthritis with Surgical Indication: A Cross-Sectional Study

Background and Objectives: The degenerative pathology of the hip joint appears in young age groups, related to fem-oroacetabular impingement, and in advanced age, due to other inflammatory causes, with greater potential for severity in the presence of comorbidities. Objectives: To evaluate the participation of the main causes of osteoarthritis in relation to physical activities, s Body Mass Index (BMI) and television time (TV). Materials and Methods: 54 patients with surgical indication treated at an orthopedic referral university hospital were stratified into groups (Impact: I, Osteonecrosis/rheumatic: II, Infectious/traumatic: III), and the influence of comorbidities on physical activity performance, relative to BMI and TV time. Results: It was observed that the impact group was the most frequent (51.8%), with 79.6% under the age of 60 years. This group followed the general mean (p < 0.05), using the variables of comorbidity and the level of physical activity. Pain intensity, TV time, BMI showed no correlation with physical activity. Conclusion: Morphostructural changes (group I) represented the most frequent etiological group, and severe pain was common in almost the entire sample. Unlike BMI, comorbidity showed a significant relationship with the level of physical activity.

Lower-limb work during high- and low-impact activities in hip-related pain: Associations with sex and symptom severity

BACKGROUND

Hip-related pain (HRP) is described as a movement-related disorder. However, little attention is given to the way people with HRP move, especially in populations still participating in sport. Thus, limiting our understanding of movementbased impairments in HRP and their potential relationships with pain/symptoms.

RESEARCH QUESTION

(1) What are the differences in absolute and relative amounts of positive and negative lower-limb joint work during walking and the single-leg drop jump (SLDJ) in football players with and without HRP? (2) What are the relationships between lower-limb joint work and HRP burden?

METHODS

88 football players with HRP and 30 control football players were recruited. Positive and negative work done by the hip, knee, and ankle (and each joint's relative contribution to total work done) were calculated. The effect of sex on the relationship between HRP and work done, as well as the association between work done and International Hip Outcome Tool (iHOT33) scores, were assessed using linear and beta regressions models.

RESULTS

Walking: No joint work variables were significantly different between groups, nor were any relationships with iHOT33 scores evident. SLDJ: The knee's relative contribution to total lower-limb negative work done was 37.7 % and 42.4 % for women with and without HRP, respectively (P = 0.04). The iHOT33 was significantly associated with positive (P = 0.03 to <0.01) and negative (P = 0.02 to <0.01) work done by the hip as well as negative work done by the ankle (P = 0.03 to 0.01), independent of sex.

SIGNIFICANCE

Only one significant between-group comparison was revealed, involving the knee in female football players. In addition, football players with a greater selfreported burden of HRP tended to display lower hip joint work during the SLDJ. Rehabilitation programs could be targeted to address these impairments and normalize work done during high impact tasks in the management of HRP.