Atrophy of hip abductor muscles is related to clinical severity in a hip osteoarthritis population

Muscle Fat and Volume Differences in People With Hip-Related Pain Compared With Controls: A Machine Learning Approach

BACKGROUND

Hip-related pain (HRP) affects young to middle-aged active adults and impacts physical activity, finances and quality of life. HRP includes conditions like femoroacetabular impingement syndrome and labral tears. Lateral hip muscle dysfunction and atrophy in HRP are more pronounced in advanced hip pathology, with limited evidence in younger populations. While MRI use for assessing hip muscle morphology is increasing, with automated deep-learning techniques showing promise, studies assessing their accuracy are limited. Therefore, we aimed to compare hip intramuscular fat infiltrate (MFI) and muscle volume, in individuals with and without HRP as well as assess the reliability and accuracy of automated machine-learning segmentations compared with human-generated segmentation.

METHODS

This cross-sectional study included sub-elite/amateur football players (Australian football and soccer) with a greater than 6-month history of HRP [n = 180, average age 28.32, (standard deviation 5.88) years, 19% female] and a control group of sub-elite/amateur football players without pain [n = 48, 28.89 (6.22) years, 29% female]. Muscle volume and MFI of gluteus maximus, medius, minimis and tensor fascia latae were assessed using MRI. Associations between muscle volume and group were explored using linear regression models, controlling for body mass index, age, sport and sex. A convolutional neural network (CNN) machine-learning approach was compared with human-performed muscle segmentations in a subset of participants (n = 52) using intraclass correlation coefficients and Sorensen-Dice index.

RESULTS

When considering adjusted estimates of muscle volume, there were significant differences observed between groups for gluteus medius (adjusted mean difference 23 858 mm3 [95% confidence interval 7563, 40 137]; p = 0.004) and tensor fascia latae (6660 mm3 [2440, 13 075]; p = 0.042). No differences were observed between groups for gluteus maximus (18 265 mm3 [-21 209, 50 782]; p = 0.419) or minimus (3893 mm3 [-2209, 9996]; p = 0.21). The CNN was trained for 30 000 iterations and assessed its accuracy and reliability on an independent testing dataset, achieving high segmentation accuracy (mean Sorenson-Dice index >0.900) and excellent muscle volume and MFI reliability (ICC2,1 > 0.900). The CNN outperformed manual raters, who had slightly lower interrater accuracy (Sorensen-Dice index >0.800) and reliability (ICC2,1 > 0.800).

CONCLUSIONS

The increased muscle volumes in the symptomatic group compared with controls could be associated with increased myofibrillar size, sarcoplasmic hypertrophy or both. These changes may facilitate greater muscular efficiency for a given load, enabling the athlete to maintain their normal level of function. In addition, the CNNs for muscle segmentation was more efficient and demonstrated excellent reliability in comparison to manual segmentations.

Automated evaluation of hip abductor muscle quality and size in hip osteoarthritis: Localized muscle regions are strongly associated with overall muscle quality

Limited information exists regarding abductor muscle quality variation across its length and which locations are most representative of overall muscle quality. This is exacerbated by time-intensive processes for manual muscle segmentation, which limits feasibility of large cohort analyses. The purpose of this study was to develop an automated and localized analysis pipeline that accurately estimates hip abductor muscle quality and size in individuals with mild-to-moderate hip osteoarthritis (OA) and identifies regions of each muscle which provide best estimates of overall muscle quality. Forty-four participants (age 52.7 ± 16.1 years, BMI 23.7 ± 3.4 kg/m2, 14 males) with and without mild-to-moderate radiographic hip OA were recruited for this study. Unilateral hip magnetic resonance (MR) images were acquired on a 3.0 T MR scanner and included axial T1-weighted fast spin echo and 3D axial Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation (IDEAL-IQ) spoiled gradient-recalled echo (SPGR) with multi-peak fat spectrum modeling and single T2* correction. A three dimensional (3D) V-Net convolutional neural network was trained to automatically segment the gluteus medius (GMED), gluteus minimus (GMIN), and tensor fascia lata (TFL) on axial IDEAL-IQ. Agreement between manual and automatic segmentation and associations between axial fat fraction (FF) estimated from IDEAL-IQ and overall muscle FF were evaluated. Dice scores for automatic segmentation were 0.94, 0.87, and 0.91 for GMED, GMIN, and TFL, respectively. GMED, GMIN, and TFL volumetric and FF measures were strongly correlated (r: 0.92-0.99) between automatic and manual segmentations, where all values fell within the 95% limits of agreement of [-9.79 cm3, 17.43 cm3] and [-1.99%, 2.89%], respectively. Axial FF was significantly associated with overall FF with the strongest correlations at 50%, 50%, and 65% the length of the GMED, GMIN, and TFL muscles, respectively (r: 0.93-0.97). An automated and localized analysis can provide efficient and accurate estimates of hip abductor muscle quality and size across muscle length. Specific regions of the muscle may be used to estimate overall muscle quality in an abbreviated evaluation of muscle quality.

The effect of experimentally induced gluteal muscle weakness on joint kinematics, reaction forces, and dynamic balance performance during deep bilateral squats

Squatting is a common daily activity and fundamental exercise in resistance training and closed kinetic chain programs. The aim of this study was to investigate the effects of an experimentally induced weakness of the gluteal muscles on joint kinematics, reactions forces (JRFs), and dynamic balance performance during deep bilateral squats in healthy young adults. Ten healthy adults received sequential blocks of (1) branch of the superior gluteal nerve to the tensor fasciae latae (SGNtfl) muscle, (2) superior gluteal nerve (SGN), and (3) inferior gluteal nerve (IGN) on the dominant right leg. At the control condition and following each block, the participants were instructed to perform deep bilateral squats standing on two force plates. Hip, knee, ankle, and pelvis kinematics did not differ significantly following iatrogenic weakness of gluteal muscles. The most important finding was the significant differences in JRFs following SGN and IGN block, with the affected hip, patellofemoral, and ankle joint demonstrating lower JRFs, whereas the contralateral joints demonstrated significantly higher JRFs, especially the patellofemoral joint which demonstrated an average maximum difference of 1.43 x body weight compared with the control condition. When performing a deep bilateral leg squat under SGN and IGN block, the subjects demonstrated an increased center of pressure (CoP) range and standard deviation (SD) in mediolateral compared with the control condition. These results imply that squat performance changes significantly following weakness of gluteal muscles and should be considered when assessing and training athletes or patients with these injuries.

CT in osteoarthritis: its clinical role and recent advances

Computed tomography (CT) is a widely available imaging method and considered as one of the most reliable techniques in bone assessment. Although CT has limited tissue contrast and needs radiation exposure, it has several advantages like fast scanning time and high spatial resolution. In this regard, CT has unique roles in osteoarthritis (OA) and its variable utilities have been reported. Hence, this review highlights the clinical role of CT in OA of representative joints. In addition, CT showed the several technical advancements recently, for example, acquiring the CT image with standing, obtaining the dual-energy data, and novel photon-counting detector development. Therefore, the recent studies and potential utility of these new CT systems in OA are also discussed.

Comparing the Effect of Exercises With Different Gluteal-to-Tensor Fasciae Latae Activation Index in Patients With Chronic Low Back Pain

CONTEXT

Hip muscle imbalance, especially between gluteal muscles and tensor fasciae latae (TFL), is one of the risk factors for developing low back pain which should be considered in rehabilitation programs. This study compared the effect of exercises with gluteal-to-TFL muscle activation index above and below 50 on pain intensity, disability, and lower limbs' range of motion (ROM) in patients with nonspecific chronic low back pain.

DESIGN

A semiexperimental intervention study with a pretest and posttest.

METHODS

A total of 45 patients with nonspecific chronic low back pain were randomly divided into 2 experimental groups of gluteal-to-TFL muscle activation index above 50 (n = 15), below 50 (n = 15), and a control group (n = 15). Pain intensity (visual analog scale), disability (Roland-Morris Disability Questionnaire), and lower limbs' ROM including hip extension, hip abduction, hip external rotation, and knee extension (goniometer) were assessed at pretest and after 8 weeks of intervention.

RESULTS

Within-group comparison showed significant improvement of pain, disability, and ROMs in both experimental groups. No significant changes were observed in the control group. In between-group analysis, significant differences were observed in group of gluteal-to-TFL muscle activation index above 50 for only pain (P = .03) and disability (P = .01). For ROMs, although clinical improvement of lower limbs' ROMs was higher in group of gluteal-to-TFL muscle activation index above 50, no statistically significant differences were found between 2 experimental groups. Both experimental groups were superior to the control group for all outcomes.

CONCLUSIONS

Findings indicate the statistically and clinically superior effectiveness of exercises with a gluteal-to-TFL muscle activation index above 50 in the reduction of pain and disability. Based on the clinical significance of exercises with a gluteal-to-TFL muscle activation index above 50 for improving ROMs, utilizing specific exercises that more activated gluteal muscle compared to TFL is recommended for patient with restricted lower limbs' ROMs.

Hip muscle activity in people with hip-related pain compared to asymptomatic controls: A systematic review

BACKGROUND

Altered hip and thigh muscle activity have been observed across a spectrum of articular hip pathologies, including hip osteoarthritis, femoroacetabular impingement syndrome, and labral pathology. No systematic reviews have examined muscle activity associated with hip pathology and hip-related pain across the life span. A greater understanding of impairments in hip and thigh muscle activity during functional tasks may assist in the development of targeted treatment strategies.

METHODS

We conducted a systematic review using the PRISMA guidelines. A literature search was performed in five databases (MEDLINE, CINAHL, EMBASE, Sports Discuss, and PsychINFO). Studies were included that (i) investigated people with hip-related pain (femoroacetabular impingement syndrome, labral tears) or hip osteoarthritis; and (ii) reported on muscle activity using electromyography of hip and thigh muscles during functional tasks such as walking, stepping, squatting, or lunging. Two independent reviewers performed data extraction and assessed risk of bias using a modified version of the Downs and Black checklist.

RESULTS

Non-pooled data demonstrated a limited level of evidence. Overall, differences in muscle activity appeared to be more prevalent in people with more advanced hip pathology.

CONCLUSIONS

We found that impairments in muscle activity in those with intra-articular hip pathology measured using electromyography were variable but appeared to be greater in severe hip pathology (e.g., hip OA).

Hip adduction angle during wider step-width gait affects hip adduction moment impulse

BACKGROUND

Decreasing an external hip adduction moment (HAM) impulse during stance is important to prevent the progression of hip osteoarthritis. A hip adduction angle (HAA) during walking influences the HAM impulse. Although a wider step-width (WS) gait is a gait modification to decrease a peak HAM, no study has reported the HAM impulse and HAA.

RESEARCH QUESTION

We investigated whether the HAA influences the peak HAM and HAM impulse during WS gait.

METHODS

Twenty-six healthy young adults walked with normal step-width (NS) and WS comfortably. They were not instructed about hip adduction motion during gait, and the peak HAM, HAM impulse, HAA, and other gait parameters were evaluated using a 3D motion capture system. The participants were divided into two groups according to the HAA size during WS gait. The percentage reduction of HAM variables (the WS condition relative to the NS condition) and other gait parameters were compared between the groups.

RESULTS

No difference in gait parameters was found between the groups. The percentage reduction of the HAM impulse in participants with smaller HAA was significantly higher than that in participants with larger HAA (14.5 % vs. 1.6 %, p < 0.01). Also, during normal step-width gait, the large HAA group showed a significantly larger HAA compared to the small HAA group (about 3°).

SIGNIFICANCE

Participants with smaller HAA could decrease the HAM impulse more effectively during WS gait compared with those with larger HAA. Thus, the HAA would influence the HAM impulse reduction effect on the WS gait. We recommend paying attention to the HAA to decrease the HAM with the WS gait.

Greater hip abductor size in prearthritic patients with developmental dysplasia of the hip versus femoroacetabular impingement

Developmental dysplasia of the hip (DDH) and femoroacetabular impingement (FAI) are common hip pathologies and important risk factors for osteoarthritis, yet the disease mechanisms differ. DDH involves deficient femoral head coverage and a shortened abductor moment arm, so this study hypothesized that the cross-sectional area (CSA) of the gluteus medius/minimus muscle complex and the stabilizing iliocapsularis muscle would be larger in DDH versus FAI, without increased fatty infiltration. A longitudinal cohort identified prearthritic patients with DDH or FAI who underwent imaging before surgery. Patients with DDH and FAI (Cam, Pincer, or Mixed) were 1:1 matched based on age, sex, and body mass index. Magnetic resonance imaging was used to measure the gluteus medius/minimus complex and iliocapsularis in two transverse planes. Amira software was used to quantify muscle and noncontractile tissue. Paired samples t-tests were performed to compare muscle size and composition (p < 0.05). There were no differences in the iliocapsularis muscle. Patients with DDH had significantly larger CSA of the gluteus medius/minimus complex at both transverse planes, and the noncontractile tissue proportion did not differ. The mean difference in overall muscle CSA at the anterior inferior iliac spine was 4.07 ± 7.4 cm² (p = 0.005), with an average difference of 12.1%, and at the femoral head this was 2.40 ± 4.37 cm² (p = 0.004), with an average difference of 20.2%. This study reports a larger CSA of the gluteus medius/minimus muscle complex in DDH compared to FAI, without a difference in noncontractile tissue, indicating increased healthy muscle in DDH.

Abductor muscle function after anterolateral approach in patients with unilateral end-stage hip osteoarthritis undergoing total hip arthroplasty: A prospective study

Background

Total hip arthroplasty (THA) is a successful procedure for treating end-stage hip osteoarthritis (OA). Regarding the surgical approach for THA, the anterolateral (AL) approach, which requires anterior hemimyotomy of the gluteus medius muscle, has shown a long-term favorable outcome. However, to date, complete information related to hip abductor muscle outcomes after the AL approach is unavailable. This study therefore aimed to evaluate the postoperative outcome of patients who undergo THA using the AL approach in terms of hip abductor muscle recovery, pain, function, and muscle healing status.

Methods

Twenty patients diagnosed with unilateral end-stage hip OA underwent cementless THA with the AL approach. All patient procedures were performed by a single surgeon. Preoperative and postoperative data were collected at 2-week, 6-week, 3-month, and 6-month follow-up periods. Hip abductor muscle power was measured via handheld dynamometer. The healing of the musculotendinous repair was evaluated with magnetic resonance imaging at 9 months.

Results

After THA, hip abductor muscle power in the operated hip significantly increased as early as 3 months post-procedure when compared with the preoperative value (p < 0.05). The other parameters-including pain score, Harris hip score, and WOMAC score-significantly improved as early as 2 weeks post-operation (p < 0.05). In all patients, MRI scans showed good healing of the muscle repair site without a gap in the gluteus medius muscle. However, three patients (15%) had some fibrosis and tendon swelling at the repair site.

Conclusion

This study demonstrated that patients with end-stage hip OA could experience significantly improved hip abductor motor function as early as 3 months after undergoing THA with the AL approach. Moreover, despite patients experiencing anterior hemimyotomy of the gluteus medius muscle, no significant complications emerged at the muscle repair site in the AL approach.

Effects of Kinesio Taping and Rigid Taping on Gluteus Medius Muscle Activation in Healthy Individuals: A Randomized Controlled Study

BACKGROUND

Gluteus medius muscle (GMed) dysfunctions may be associated with pain and functional problems in the lumbar spine and lower limbs. The study sought to assess the effects of applying kinesio taping (KT) and rigid taping (RT) on GMed in the dominant leg of healthy individuals. Furthermore, an attempt was made to indicate which of the applied exercises brought about the greatest activation of GMed.

METHODS

The study included 90 individuals, with an average age of 21.79. The participants were randomly assigned to one of three groups: kinesio tape (KT), rigid tape (RT) and placebo tape (C). GMed activation was assessed using sEMG during the performance of such exercises as glute bridge, unilateral glute bridge, clamshell, pelvic drop and lunge. Each of the participants was examined three times-before taping, immediately after and 48 h after taping.

RESULTS

Before taping, the greatest GMed activation on the dominant side was noted in clamshell (54.12 %MVIC), whereas the lowest GMed activation was observed in glute bridge (36.35 %MVIC). The comparison of results obtained before and immediately after taping in all the groups revealed a statistically significant increase in GMed activation (p < 0.05), while the comparison of results achieved before and 48 h after taping showed significant differences in glute bridge in groups KT and RT. In all the groups, the differences in results obtained in the other exercises were not significant. Taking into account each of the applied exercises, at none of the three stages of examination were the differences between the groups significant.

CONCLUSIONS

Regardless of the type of taping applied (KT, RT, C), a significant increase in GMed activation was noted in all the exercises immediately after taping. At none of the stages of examination were the differences between the groups significant.

Prefabricated contoured foot orthoses to reduce pain and increase physical activity in people with hip osteoarthritis: protocol for a randomised feasibility trial

INTRODUCTION

The aim of this randomised feasibility trial is to determine the feasibility of conducting an adequately powered randomised controlled trial (RCT) investigating the efficacy of prefabricated contoured foot orthoses in people with hip osteoarthritis (OA). The secondary aims of the trial are to compare the effect of prefabricated contoured foot orthoses to a flat shoe insert comparator on outcomes of hip-related pain, physical activity and quality of life. We hypothesise that the demand, implementation, acceptability and practicality of foot orthoses as a treatment option for people with hip OA will be deemed feasible, informing the development of an adequately powered RCT to evaluate the efficacy and long term outcomes.

METHODS AND ANALYSIS

We will recruit 28 people with hip OA who will be randomised to receive either prefabricated contoured foot orthoses or flat shoe inserts to use for a 6-week period. Both groups will receive standardised education on hip OA and physical activity. The study's primary outcome is the feasibility domains of demand, implementation, acceptability and practicality. The secondary outcomes include the change in Hip Osteoarthritis Outcome Score-12, Patient Health Questionnaire-9, Brief Fear of Movement Scale for OA, Physical activity accelerometry and the Physical Activity Questionnaire-short form. Descriptive statistics will be used to describe feasibility outcomes with limited efficacy analysis used for the secondary outcomes. Linear mixed models will be used to analyse between-group differences at 6 weeks, with baseline values used as covariates, treatment allocation as a fixed factor and participant as a random factor.

ETHICS AND DISSEMINATION

This trial has been approved by the La Trobe University Human Research Ethics Committee (HEC20427), St. Vincent's Hospital Melbourne, Human Research Ethics Committee (HREC 266/20) and Northern Health Research Governance (NH-2021-292862). The results will be disseminated via a peer-reviewed journal and presented at international conferences.

TRIAL REGISTRATION NUMBER

NCT05138380.

Towards defining muscular regions of interest from axial magnetic resonance imaging with anatomical cross-reference: a scoping review of lateral hip musculature

Background

Measures of hip muscle morphology and composition (e.g., muscle size and fatty infiltration) are possible with magnetic resonance imaging (MRI). Standardised protocols or guidelines do not exist for evaluation of hip muscle characteristics, hindering reliable and valid inter-study analysis. This scoping review aimed to collate and synthesise MRI methods for measuring lateral hip muscle size and fatty infiltration to inform the future development of standardised protocols.

Methods

Five electronic databases (Medline, CINAHL, Embase, SportsDISCUS and AMED) were searched. Healthy or musculoskeletal pain populations that used MRI to assess lateral hip muscle size and fatty infiltration were included. Lateral hip muscles of interest included tensor fascia late (TFL), gluteus maximus, gluteus medius, and gluteus minimus. Data on MRI parameters, axial slice location, muscle size and fatty infiltrate measures were collected and analysed. Cross referencing for anatomical locations were made between MRI axial slice and E-12 anatomical plastinate sections.

Results

From 2684 identified publications, 78 studies contributed data on volume (n = 31), cross sectional area (CSA) (n = 24), and fatty infiltration (n = 40). Heterogeneity was observed for MRI parameters and anatomical boundaries scrutinizing hip muscle size and fatty infiltration. Seven single level axial slices were identified that provided consistent CSA measurement, including three for both gluteus maximus and TFL, and four for both gluteus medius and minimus. For assessment of fatty infiltration, six axial slice locations were identified including two for TFL, and four for each of the gluteal muscles.

Conclusions

Several consistent anatomical levels were identified for single axial MR slice to facilitate muscle size and fatty infiltration muscle measures at the hip, providing the basis for reliable and accurate data synthesis and improvements in the validity of future between studies analyses. This work establishes the platform for standardised methods for the MRI assessment of lateral hip musculature and will aid in the examination of musculoskeletal conditions around the hip joint. Further studies into whole muscle measures are required to further optimise methodological parameters for hip muscle assessment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05439-x.

Comparison between movement pattern training and strengthening on muscle volume, muscle fat, and strength in patients with hip-related groin pain: An exploratory analysis

The purpose of this exploratory analysis was to compare the impact of movement pattern training (MoveTrain) and standard strength and flexibility training (Standard) on muscle volume, strength and fatty infiltration in patients with hip-related groin pain (HRGP). We completed a secondary analysis of data collected during an assessor-blinded randomized control trial. Data were used from 27 patients with HRGP, 15-40 years, who were randomized into MoveTrain or Standard groups. Both groups participated in their training protocol (MoveTrain, n = 14 or Standard, n = 13) which included 10 supervised sessions over 12 weeks and a daily home exercise program. Outcome measures were collected at baseline and immediately after treatment. Magnetic resonance images data were used to determine muscle fat index (MFI) and muscle volume. A hand-held dynamometer was used to assess isometric hip abductor and extensor strength. The Standard group demonstrated a significant posttreatment increase in gluteus medius muscle volume compared to the MoveTrain group. Both groups demonstrated an increase in hip abductor strength and reduction in gluteus minimus and gluteus maximus MFI. The magnitude of change for all outcomes were modest. Statement of Clinical Significance: Movement pattern training or a program of strength/flexibility training may be effective at improving hipabductor strength and reducing fatty infiltration in the gluteal musculature among those with HRGP. Further research is needed to betterunderstand etiology of strength changes and impact of muscle volume and MFI in HRGP and the effect of exercise on muscle structure andfunction.

Hip Range of Motion and Strength Predict 12-Month Physical Function Outcomes in Older Adults With Chronic Low Back Pain: The Delaware Spine Studies

Objective

The objective of this study was to investigate whether poor hip range of motion (ROM) and strength predict 12‐month physical function decline among older adults with chronic low back pain (LBP) and whether hip osteoarthritis modifies those relationships.

Methods

At baseline, passive ROM and strength measurements were taken for hip flexion, extension, abduction, adduction, internal rotation, and external rotation; ultrasound images and self‐reported symptoms were used to evaluate hip osteoarthritis presence (eg, osteophytes and hip pain). At baseline and 12 months, performance‐based (repeated chair rise, self‐selected gait speed, 6‐minute walk test [6MWT]) and self‐reported (Quebec LBP Disability Questionnaire, Late‐Life Function & Disability Instrument [LLFDI] basic and advanced lower extremity scales) physical function outcomes were assessed. Regression models were constructed for each outcome predicted by baseline hip ROM and strength measures, with adjustment for potential covariates. To avoid collinearity, hip ROM and strength measures with the strongest unadjusted correlations were included in final models. The hip osteoarthritis presence by hip ROM/strength interaction was also explored.

Results

Hip abduction strength predicted repeated chair rise (β = −0.297, P < 0.001), gait speed (β = 0.160, P = 0.003), 6MWT (β = 0.159, P ≤ 0.001), Quebec LBP Disability Questionnaire (β = −0.152, P = 0.003), and LLFDI basic lower extremity scale (β = 0.171, P = 0.005) outcomes. Regarding hip ROM, extension predicted repeated chair rise (β = −0.110, P = 0.043) and LLFDI advanced lower extremity scale (β = 0.090, P = 0.007) outcomes, external rotation predicted gait speed (β = 0.122, P = 0.004) outcomes, and abduction predicted LLFDI basic lower extremity scale (β = 0.114, P = 0.026) outcomes. The hip osteoarthritis interaction was not significant for any model.

Conclusion

Reduced hip strength and ROM predict physical function decline; hip osteoarthritis presence may not modify these relationships.

Association of tensor fascia lata hypertrophy and fatty infiltration in the presence of abductor tendon tears: a radiographic study

Hip abductor tendon tears of the gluteus medius and minimus are becoming a well-recognized source of pain and dysfunction, primarily in middle-age females. Like the rotator cuff, fatty infiltration (FI) can occur after tearing of these tendons. While the association of TFL hypertrophy after abductor tendon tears has been established, its association with FI has not been well studied. Our hypothesis is that hypertrophy of the TFL will be associated with FI of the abductors. All patients &gt;18 years old undergoing primary surgical repair for a confirmed tears on MRI, without a history of prior hip surgery or osteoarthritis, were included. The following measurements were obtained from MRI: TFL cross-sectional area, TFL:sartorius volume ratio, and modified Goutallier grade of gluteus medius and minimus. Seventy patients met inclusion criteria and were divided in two groups, those with (n = 28) and those without FI (n = 42) of the abductors. The FI group was on average older (65 versus 58 years, P &lt; 0.00016). TFL hypertrophy and TFL:sartorius volume ratio were significantly associated with FI (P= 0.00069). Following abductor tendon tear and subsequent FI, there exists significant TFL hypertrophy in patients without a prior history of hip surgery in our patient cohort.

Quantitative Evaluation of Hip Muscle Atrophy in Patients with Unilateral Slipped Capital Femoral Epiphysis Based on Magnetic Resonance Imaging

RATIONALE AND OBJECTIVES

Hip muscle atrophy commonly occurs in patients with unilateral slipped capital femoral epiphysis (SCFE), its effect in patients with unilateral SCFE is worthy of further investigation. This study aimed to investigate the relationship between hip muscle cross-sectional area (M-CSA) and unilateral SCFE using magnetic resonance imaging.

MATERIALS AND METHODS

Overall, 32 unilateral SCFE patients (SCFE group) and 15 asymptomatic subjects (control group) were evaluated. All patients underwent magnetic resonance imaging and frog-leg lateral radiograph examinations. M-CSA and Southwick angle were evaluated to calculate the M-CSA ratio of the affected side over the healthy side (A/H) ratio in the SCFE group and the control group. Associations between the A/H ratio, Southwick angle, and the disease time course were investigated with Spearman correlation test. An independent sample t-test, one-way analysis of variance tests, and intraclass correlation coefficients were also applied.

RESULTS

A/H ratios of the control group were significantly higher than those of the SCFE group (anterior muscles group: 1.09 ± 0.14 vs 0.86 ± 0.12, medial muscles group: 1.02 ± 0.15 vs 0.82 ± 0.18, posterior muscles group: 1.03 ± 0.07 vs 0.84 ± 0.11, all p < 0.01). A/H ratios of the medial and posterior muscle groups were significantly correlated with severity of SCFE (r = -0.504, p = 0.003, and r = -0.438, p = 0.012, respectively).

CONCLUSION

Hip muscle atrophy is associated with SCFE severity in patients with unilateral SCFE. The A/H ratio can reflect the patients' prognosis and rehabilitation status. Maintenance of hip muscle morphology and function may be beneficial to clinical performance and prognosis of patients with unilateral SCFE.

Relative Efficacy of Weight Management, Exercise, and Combined Treatment for Muscle Mass and Physical Sarcopenia Indices in Adults with Overweight or Obesity and Osteoarthritis: A Network Meta-Analysis of Randomized Controlled Trials

Aging and osteoarthritis are associated with high risk of muscle mass loss, which leads to physical disability; this loss can be effectively alleviated by diet (DI) and exercise (ET) interventions. This study investigated the relative effects of different types of diet, exercise, and combined treatment (DI+ET) on muscle mass and functional outcomes in individuals with obesity and lower-limb osteoarthritis. A comprehensive search of online databases was performed to identify randomized controlled trials (RCTs) examining the efficacy of DI, ET, and DI+ET in patients with obesity and lower-extremity osteoarthritis. The included RCTs were analyzed through network meta-analysis and risk-of-bias assessment. We finally included 34 RCTs with a median (range/total) Physiotherapy Evidence Database score of 6.5 (4-8/10). DI plus resistance ET, resistance ET alone, and aerobic ET alone were ranked as the most effective treatments for increasing muscle mass (standard mean difference (SMD) = 1.40), muscle strength (SMD = 1.93), and walking speed (SMD = 0.46). Our findings suggest that DI+ET is beneficial overall for muscle mass in overweight or obese adults with lower-limb osteoarthritis, especially those who are undergoing weight management.

Tensor Fascia Latae Muscle Structure and Activation in Individuals With Lower Limb Musculoskeletal Conditions: A Systematic Review and Meta-Analysis

BACKGROUND

Dysfunction of the tensor fascia latae (TFL) muscle is often clinically implicated in many musculoskeletal disorders.

OBJECTIVE

To systematically review the literature of the TFL muscle to determine whether there are differences in its structure and activation between individuals with and without lower limb musculoskeletal conditions.

DATA SOURCES

A comprehensive search in MEDLINE, EMBASE, CINHAL, and LILACS was undertaken from year of inception to 9 July 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies that directly investigated the structure or activity of the TFL muscle between individuals with a lower limb musculoskeletal condition and a pain-free control group.

RESULTS

Seventeen studies were included (n = 556 participants), eight reporting structure and ten activation of the TFL muscle. Conditions included lateral hip pain, hip joint pathology, ACL injury, iliotibial band syndrome, and patellofemoral joint osteoarthritis. Meta-analysis identified with low confidence (p value = 0.07) a small tendency towards hypertrophy in the affected side of participants with hip joint diseases (SMD 0.37, 95% CI [- 0.02, 0.77]). Moderate effect sizes were found for a higher cross-sectional area of the TFL/sartorius ratio in abductor tendon tear (SMD 0.74; 95% CI [0.05, 1.43, p value = 0.04), and for a smaller body mass normalized TFL volume in patellofemoral joint osteoarthritis (SMD - 0.61; 95% CI [- 1.23, 0.00], p value = 0.05). Normalised electromyography (EMG) amplitude did not differ between groups for any condition, but when EMG was analysed as linear envelopes or synergies, some differences in pattern of TFL activation were observed between individuals with lateral hip pain and controls. Timing of TFL activation did not differ between individuals with knee conditions and controls.

CONCLUSIONS AND IMPLICATIONS

Common clinical assumptions of the role of TFL muscle in lower limb musculoskeletal conditions are not well investigated and poorly supported by current research. There are contradictory findings on the muscle size of TFL. Differing methodology in muscle activation studies precludes a clear interpretation for comparison between groups.

PROSPERO REGISTRATION NUMBER

CRD42017076160.

Gluteal atrophy and fatty infiltration in end-stage osteoarthritis of the hip: a case-control study

Aims

The gluteus minimus (GMin) and gluteus medius (GMed) have unique structural and functional segments that may be affected to varying degrees, by end-stage osteoarthritis (OA) and normal ageing. We used data from patients with end-stage OA and matched healthy controls to 1) quantify the atrophy of the GMin and GMed in the two groups and 2) describe the distinct patterns of the fatty infiltration in the different segments of the GMin and GMed in the two groups.

Methods

A total of 39 patients with end-stage OA and 12 age- and sex frequency-matched healthy controls were prospectively enrolled in the study. Fatty infiltration within the different segments of the GMin and the GMed was assessed on MRI according to the semiquantitative classification system of Goutallier and normalized cross-sectional areas were measured.

Results

The GMin was smaller in the OA-group (p < 0.001) compared to the control group, but there was no group difference in the size of the GMed (p = 0.101). Higher levels of fatty infiltration were identified in the anterior segment of the GMin (p = 0.006) and the anterior (p = 0.006) and middle (p = 0.047) segments of the GMed in the OA group. All subjects in the control group had fatty infiltration of the anterior segment of the GMin, but all except one had no fatty infiltration in the entire GMed.

Conclusion

End-stage OA was associated with significant atrophy of the GMin and higher levels of fatty infiltration, particularly in the anterior segments of the GMin and GMed. Minor fatty infiltration of the anterior segment of GMin appears to be a normal part of ageing. Our study has demonstrated different patterns of atrophy and fatty infiltration between patients with end-stage OA and healthy matched peers.

Cite this article: Bone Jt Open 2021;2(1):40–47.

Effects of Muscle Strength Training on Muscle Mass Gain and Hypertrophy in Older Adults With Osteoarthritis: A Systematic Review and Meta-Analysis

OBJECTIVE

To investigate the effect of muscle strength exercise training (MSET) on lean mass (LM) gain and muscle hypertrophy in older patients with lower extremity osteoarthritis (OA).

METHODS

A comprehensive search of online databases was performed on April 20, 2019. Randomized controlled trials (RCTs) that reported the effects of MSET on LM, muscle thickness, and cross-sectional area (CSA) in older patients with OA were identified. A risk of bias assessment and meta-analysis were performed for the included RCTs.

RESULTS

We included 19 RCTs with a median Physiotherapy Evidence Database score of 6 of 10 (range 3-7). In total, data from 1,195 patients (65% women, 85% with knee OA) with a mean age of 62.1 years (range 40-86 years) were analyzed. MSET resulted in significantly higher LM gain (standardized mean difference [SMD] 0.49 [95% confidence interval (95% CI) 0.28, 0.71], P < 0.00001) than did the nonexercise controls. Meta-analysis results revealed significantly positive effects of MSET on muscle thickness (SMD 0.82 [95% CI 0.20, 1.43], P = 0.009) and CSA (SMD 0.80 [95% CI 0.25, 1.35], P = 0.004) compared with nonexercise controls. No significant effects in favor of MSET were observed for any muscle outcome compared with exercise controls. Five RCTs reported nonsevere adverse events in response to MSET, whereas no RCTs reported severe events.

CONCLUSION

MSET is effective in increasing LM and muscle size in older adults with OA. Clinicians should incorporate MSET into their management of patients at risk of low muscle mass to maximize health status, particularly for older individuals with OA.

A SYSTEMATIC REVIEW AND META-ANALYSIS OF COMMON THERAPEUTIC EXERCISES THAT GENERATE HIGHEST MUSCLE ACTIVITY IN THE GLUTEUS MEDIUS AND GLUTEUS MINIMUS SEGMENTS

Background

The gluteus medius (GMed) and gluteus minimus (GMin) muscle segments demonstrate different responses to pathology and ageing, hence it is important in rehabilitation that prescribed therapeutic exercises can effectively target the individual segments with adequate exercise intensity for strengthening.

Purpose

The purpose of this systematic review was to evaluate whether common therapeutic exercises generate at least high ( > 40% maximum voluntary isometric contraction (MVIC)) electromyographic (EMG) activity in the GMed (anterior, middle and posterior) and GMin (anterior and posterior) segments.

Methods

Seven databases (MEDLINE, EMBASE, CINAHL, AusSPORT, PEDro, SPORTdiscus and Cochrane Library) were searched from inception to May 2018 for terms relating to gluteal muscle, exercise, and EMG. The search yielded 6918 records with 56 suitable for inclusion. Quality assessment, data extraction and data analysis were then undertaken with exercise data pooled into a meta-analysis where two or more studies were available for an exercise and muscle segment.

Results

For the GMed, different variations of the hip hitch/ pelvic drop exercise generated at least high activity in all segments. The dip test, and isometric standing hip abduction are other options to target the anterior GMed segment, while isometric standing hip abduction can be used for the posterior GMed segment. For the middle GMed segment, the single leg bridge; side-lying hip abduction with hip internal rotation; lateral step-up; standing hip abduction on stance or swing leg with added resistance; and resisted side-step were the best options for generating at least high activity. Standing isometric hip abduction and different variations of the hip hitch/ pelvic drop exercise generated at least high activity in all GMin segments, while side-lying hip abduction, the dip test, single leg bridge and single leg squat can also be used for targeting the posterior GMin segment.

Conclusion

The findings from this review provide the clinician with confidence in exercise prescription for targeting individual GMed and GMin segments for potential strengthening following injury or ageing.

Level of Evidence

Level 1.

What is known about the subject

Previous reviews on GMed exercises have been based on single electrode, surface EMG measures at middle GMed segment. It is not known whether these exercises effectively target the other segments of GMed or the GMin at a sufficient intensity for strengthening.

What this study adds to existing knowledge

This review provides the clinician with confidence in exercise prescription of common therapeutic exercises to effectively target individual GMed and GMin segments for potential strengthening.

Behavior of the muscle quality index and isometric strength in elderly women

This study aimed (I) to compare the muscle quality index (MQI) and the isometric hip strength between younger and older women, and (II) to determine the relationship of the MQI with the sit-to-stand test (STS) and isometric hip strength in younger and older women. Twenty-eight elderly women (age= 66.2 ± 5.6 years) and twenty younger women (21.2 ± 2.2 years) participated in the study. The following dependent variables were measured: MQI, STS, body composition, and the peak isometric strength of the hip (PF) which was also normalized using three different methods (PF/Body Mass, PF/Fat-Free Mass, and PF/Body Mass^0,335). Older women presented a lower PF in hip flexion, extension and external rotation regardless of the method of normalization (p < 0.001), but the PF of hip abductors and internal rotators was higher for older women (p < 0.05). No significant differences were found in the MQI between older and younger women (p = 0.443). The MQI was negatively correlated with the time in the STS in older women (r = -0.706, p < 0.001) and younger women (r = -0.729, p < 0.001), while the correlations of MQI with isometric hip strength were weaker in older women (r range: -0.082 - 0.556) and younger women (r range: -0.020 - 0.309). MQI is a clinical and practical tool to assess the muscular power of the lower extremities.

Morphometric analysis of all 24 hip muscles: A cadaveric study of 18 hip specimens with proposal of a new classification of muscles

PURPOSE

There are few papers investigating the morphometry of hip muscles and reporting either a single muscle or a group of synergistic muscles. With the development of hip joint simulation, hip arthroplasty implants, and gait analysis, a set of biometric data covering all the muscles that act on the hip joint is needed.

METHODS

Using a rigorous dissection process on 18 cadaveric hips, measurements of all 24 hip muscles and bone parameters were conducted. We measured the following: (a) total femur, femoral shaft, and neck lengths, (b) total muscle lengths, (c) intra-muscular and extra-muscular (free) tendon lengths, (d) bone angles, (e) muscle pennation, sagittal, and frontal angles, (f) muscle weight, (g) muscle volume, (h) muscle cross-sectional area, and (i) and bending moment. Data on more than 12,000 morphometric or anatomical parameters were collected. Correlation values between bone variables, muscle variables, and in-between muscle variables were computed. Based on their compliance, muscles were classified using the ratio of belly length over the sum of intra-muscular and free tendons.

RESULTS

Values of the neck, shaft, and total femur lengths were highly correlated in relation to each other. The long muscles and the pelvitrochanteric muscles were highly correlated with femoral bone lengths. The proximal and distal intra-muscular tendon lengths were correlated to the total muscle length for all long muscles, independently of free tendon (extra-muscular) or muscle belly lengths. A very significant correlation was found between muscle weight variations among specimens. Three groups of muscles were identified based on their compliance.

CONCLUSION

This is the first comprehensive anatomical morphometric study which includes all the 24 muscles acting on the hip joint. It generates a unique anatomical dataset comprising all necessary data for musculoskeletal modeling and arthroplasty implants of the hip joint. A new muscle classification was proposed based on compliance where muscles of the same group would exhibit similar compliance and functional anatomy.

Gluteus medius and minimus activity during stepping tasks: Comparisons between people with hip osteoarthritis and matched control participants

BACKGROUND

Altered gluteus minimus (GMin) activity has been identified in people with hip osteoarthritis (OA) during gait with some evidence of altered gluteus medius (GMed) activity in patients with advanced OA. It is not known whether these muscles also exhibit altered activity during other functional tasks.

RESEARCH QUESTION

Does gluteal muscle activity during stepping tasks differ between people with hip OA and healthy older adults?

METHODS

Participants included 20 people with unilateral hip OA and 20 age-and sex-matched controls. Muscle activity in the three segments within GMed and two segments of GMin were examined using intramuscular electromyography during step-up, step-down and side-step tasks.

RESULTS

Participants in the OA group demonstrated reduced muscle activity early in the step-up task and a later time to peak activity in most muscle segments. Greater activity was identified in anterior GMin in people with hip OA during the side-step task. A delay in time to peak activity was identified in most muscle segments in people with OA during the side-step task.

SIGNIFICANCE

For participants with OA, reduced activity in most muscle segments and increased time spent in double limb stance during the step-up task could reflect the decreased strength and pain associated with single limb stance on the affected limb. This study provides further evidence of altered function of the deep gluteal muscles in people with hip OA and highlights the importance of addressing these muscles in rehabilitation.

Reconnecting the Brain With the Rest of the Body in Musculoskeletal Pain Research

A challenge in understanding chronic musculoskeletal pain is that research is often siloed between neuroscience, physical therapy/rehabilitation, orthopedics, and rheumatology which focus respectively on 1) neurally mediated effects on pain processes, 2) behavior and muscle activity, 3) tissue structure, and 4) inflammatory processes. Although these disciplines individually study important aspects of pain, there is a need for more cross-disciplinary research that can bridge between them. Identifying the gaps in knowledge is important to understand the whole body, especially at the interfaces between the silos-between brain function and behavior, between behavior and tissue structure, between musculoskeletal and immune systems, and between peripheral tissues and the nervous system. Research on "mind and body" practices can bridge across these silos and encourage a "whole person" approach to better understand musculoskeletal pain by bringing together the brain and the rest of the body. PERSPECTIVE: Research on chronic musculoskeletal pain is limited by significant knowledge gaps. To be fully integrated, musculoskeletal pain research will need to bridge across tissues, anatomical areas, and body systems. Research on mind and body approaches encourages a "whole person" approach to better understand musculoskeletal pain.

Association between hip muscle cross-sectional area and hip pain and function in individuals with mild-to-moderate hip osteoarthritis: a cross-sectional study

BACKGROUND

To examine the associations between hip muscle cross-sectional area and hip pain and function in community-based individuals with mild-to-moderate hip osteoarthritis.

METHODS

This study included 27 participants with mild-to-moderate hip osteoarthritis. Cross-sectional area of hip muscles, including psoas major, rectus femoris, gluteus maximus, gluteus medius and minimus, adductor longus and magnus, obturator internus, and obturator externus, were measured from magnetic resonance images. Hip pain and function were evaluated using the Hip Disability and Osteoarthritis Outcome Score (HOOS) categorised into 5 subscales: pain, symptoms, activity of daily living, sport and recreation function, and hip-related quality of life (for each subscale 0 representing extreme problems and 100 representing no problems).

RESULTS

Mean age of the 27 participants was 63.2 (SD 7.6) years and 66.7% (n = 18) were female. After adjusting for age and gender, greater cross-sectional area of adductor longus and magnus was associated with a higher HOOS score in quality of life (regression coefficient 1.4, 95% confidence interval (CI) 0.2-2.7, p = 0.02), activity of daily living (regression coefficient 1.3, 95% CI 0.1-2.6, p = 0.04) and sport and recreation function (regression coefficient 1.6, 95% CI 0.1-3.0, p = 0.04). There was a trend towards an association between greater cross-sectional area of psoas major and a higher quality of life score (regression coefficient 3.6, 95% CI - 0.5 to 7.7, p = 0.08). The cross-sectional area of hip muscles was not significantly associated with HOOS pain or symptom score.

CONCLUSION

Greater cross-sectional area of hip adductors was associated with better function and quality of life in individuals with mild-to-moderate hip osteoarthritis. Greater cross-sectional area of hip flexors might be associated with better quality of life. These findings, while need to be confirmed in longitudinal studies, suggest that targeting the hip adductor and flexor muscles may improve function and quality of life in those with mild-to-moderate hip osteoarthritis.

Does low back pain or leg pain in gluteus medius syndrome contribute to lumbar degenerative disease and hip osteoarthritis and vice versa? A literature review

[Purpose] Gluteus medius syndrome is one of the major causes of back pain or leg pain and is similar to greater trochanteric pain syndrome, which also presents with back pain or leg pain. Greater trochanteric pain syndrome is associated with lumbar degenerative disease and hip osteoarthritis. The objective of this review was to demonstrate gluteus medius syndrome as a disease entity by reviewing relevant articles to elucidate the condition. [Methods] Gluteus medius syndrome was defined as myofascial pain syndrome arising from the gluteus medius. We performed a search of the literature using the following keywords: “back pain”, “leg pain”, “greater trochanteric pain syndrome”, “degenerative lumbar disease”, “hip osteoarthritis”, and “gluteus medius”. We reviewed articles related to gluteus medius syndrome and described the findings in terms of diagnosis and treatment based on the underlying pathology. [Results] A total of 135 articles were included in this review. Gluteus medius syndrome is similar as a disease entity to greater trochanteric pain syndrome, which presents with symptoms of low back pain and leg pain. Gluteus medius syndrome is also related to lumbar degenerative disease, hip osteoarthritis, knee osteoarthritis, and failed back surgery syndrome. [Conclusion] Accurate diagnosis of gluteus medius syndrome and appropriate treatment could possibly improve lumbar degenerative disease and osteoarthritis of the hip and knee, as well as hip-spine syndrome and failed back surgery syndrome.

Muscle quality index and isometric strength in older adults with hip osteoarthritis

Background

Older adults with hip osteoarthritis (OA) suffer a progressive loss of muscle quality and strength, affecting their daily activities and quality of life. The purpose of this study is to compare the levels of isometric strength among older adults with and without hip OA and healthy young adults, and to determine the relationship between muscle quality index (MQI) and isometric strength.

Methods

Fourteen subjects with hip OA (65.6 ± 3.0 years), 18 healthy older adults (66.6 ± 6.5 years) and 32 young adults (20.7 ± 2.0 years) participated in the study. MQI, isometric muscle strength of the hip, ten time sit-to-stand tests, and body composition were measured.

Results

The MQI was lower in subjects with hip OA, with no significant differences between groups (p > 0.054). Subjects with OA produced significantly less isometric strength in hip extension (p < 0.001), flexion (p < 0.001), abduction (p < 0.05), adduction (p < 0.001), external (p < 0.05) and internal rotation (p < 0.05). Subjects with OA demonstrated longer time in the execution of the sit-to-stand test (p < 0.001) in comparison with healthy older and young adults. High correlations between MQI, sit-to-stand (r =  - 0.76, p < 0.01) and peak force during hip abduction (r = 0.78, p < 0.01) where found in subjects with OA. Moderate correlation between MQI and peak force during hip flexion (r = 0.55, p < 0.05) and external rotation (r = 0.61, p < 0.05) were found in the OA group.

Conclusions

Subjects with OA have lower MQI than old and young healthy controls. In subjects with OA, there was a significant relationship between isometric strength of hip muscles and performance on the sit-to-stand test and the MQI.

Muscle size and composition in people with articular hip pathology: a systematic review with meta-analysis

OBJECTIVE

To synthesise and evaluate the current evidence investigating muscle size and composition in non-inflammatory articular hip pathology.

METHODS

A systematic review of five electronic databases, using three concepts; articular hip pathology (e.g., osteoarthritis (OA)); hip muscles; and outcomes (e.g., muscle size and adiposity) was undertaken. Studies addressing non-inflammatory or non-traumatic articular hip pain, using measures of muscle size and adiposity were included and appraised for risk of bias. Data was extracted to calculate standardised mean differences (SMD) and pooled where possible for meta-analysis.

RESULTS

Thirteen cross-sectional studies were included; all studies measured muscle size and 5/13 measured adiposity. In OA, there was low to very low quality evidence of no difference in hip muscle size, compared with matched controls. In unilateral OA, there was low to very low quality evidence of smaller size in gluteus minimus (SMD -0.38; 95% confidence interval (CI) -0.74, -0.01), gluteus medius (-0.44; 95% CI: -0.83, -0.05) and gluteus maximus (-0.39; 95% CI: -0.75, -0.02) muscles in the symptomatic limb. Individual studies demonstrated non-uniform changes in muscle size in OA. No significant difference was observed in muscle size in other pathologies or in adiposity for any group.

CONCLUSION

There is some low quality evidence that specific hip muscles are smaller in unilateral hip OA. Variation in the magnitude of differences indicate changes in size are not uniform across all muscles or stage of pathology. Studies in larger cohorts investigating muscle size and composition across the spectrum of articular pathologies are required to clarify these findings.

Targeted gluteal exercise versus sham exercise on self-reported physical function for people with hip osteoarthritis (the GHOst trial - Gluteal exercise for Hip Osteoarthritis): a protocol for a randomised clinical trial

BACKGROUND

Clinical practice guidelines recommend exercise as the first line of management for hip osteoarthritis, yet high-quality evidence from Cochrane reviews suggest only slight benefits for pain and physical function; and no benefit on quality of life (low-quality evidence). However, the scope of physical impairments identified in people with hip osteoarthritis may not have been adequately addressed with targeted rehabilitation options in previous randomised controlled trials (RCTs). Potential targeted options include gait retraining to address spatio-temporal impairments in walking; motor control training to address deep gluteal (gluteus minimus) dysfunction; and progressive, high-intensity resistance exercises to address atrophy of the gluteal muscles. The aim of this study is to investigate the effect of a targeted gluteal rehabilitation programme that incorporates gait retraining, motor control and progressive, high-intensity resistance-strength training, to address physical activity levels and self-reported physical function in people with mild to moderate disability from hip osteoarthritis.

METHODS

Ninety people diagnosed with mild to moderately disabling hip osteoarthritis will be recruited and randomised to receive one of two exercise programmes (sham or GHOst programme). Interventions will be 12 weeks in duration, with weekly, supervised physiotherapy sessions, and daily home exercises. Both groups will receive standardised education. Outcomes will be assessed at baseline, 7 weeks, 13 weeks (primary time-point) and 25 weeks. The primary outcome will be self-reported physical function measured with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Secondary outcomes include physical activity measured with a tri-axial accelerometer, physical function tests, self-reported physical activity, isometric hip-muscle strength tests, hip-related patient-reported outcome measures, pain thoughts and depressive symptoms, quality of life, global rating of change, gluteal-muscle activity (electromyography (EMG)) and gluteal-muscle size and adiposity (magnetic resonance imaging (MRI)).

DISCUSSION

This will be the first study to compare a targeted gluteal rehabilitation programme to a sham exercise programme. The targeted GHOst programme includes exercises designed to address gait impairments as well as gluteal-muscle atrophy and dysfunction.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry, ID: ACTRN12617000970347 . Registered retrospectively on 5 July 2017. Protocol version 3.0.