Individuals with mild-to-moderate hip osteoarthritis have lower limb muscle strength and volume deficits

Predictive and classification capabilities of the timed up and go as a physical performance measure in hip osteoarthritis: a retrospective study of 606 patients

INTRODUCTION

Hip osteoarthritis (OA) is a common joint pathology that significantly constrains functional capacity. Assessing the impact of hip OA on functionality is crucial for research and clinical practices. The study aimed to assess hip OA patients' functionality using the Timed Up and Go (TUG) test and to evaluate its diagnostic ability to differentiate between different grades of hip OA. We hypothesized that the severity of hip OA would impact the time required to complete the TUG test.

MATERIALS AND METHODS

Patients (Ν = 606) with unilateral, primary hip OA were selected from de-identified data and divided according to the radiographic Kellgren-Lawrence classification system (groups: Grade 2, Grade 3, and Grade 4). Groups' differences were assessed using the X2 test of independence and the one-way ANOVA model. Correlations between dependent and independent variables were assessed using Pearson's correlation coefficient (r). A receiver operating characteristic (ROC) analysis was conducted to assess the TUG test's ability to differentiate between the hip OA grades.

RESULTS

Statistically significant differences were found among the three groups in age, gender distribution, TUG test, and occasional cane use (all p-values < 0.001). The correlation analysis shows a significant and strong positive correlation between TUG performance time and hip OA grades (r = .78, p < .001). The adjusted odds ratios (OR) were: Grade2-3=(2.29[95%CI: 1.89, 2.77], p < .001) and Grade3-4=(1.47[95%CI: 1.34, 1.62], p < .001). The TUG cut-off points from the ROC analysis were: Grades 2-3 = 10.25 s, Grades 2-4 = 11.35 s, and Grades 3-4 = 12.8 s.

CONCLUSIONS

This study provides evidence that the duration of the TUG test significantly increased with the severity of the disease. TUG can offer real-time data on the management and progression of hip OA. Future studies should explore the correlation between hip OA and the TUG test, as understanding the relationship can influence treatment and patient outcomes.

Individual joint contributions to forward propulsion during treadmill walking in women with hip osteoarthritis

As we age, reliance on the ankle musculature for push-off during walking reduces and increased reliance on the hip musculature is observed. It is unclear how joint pathology like osteoarthritis may affect this distal-to-proximal redistribution of propulsion. Here, we revisited a proof-of-concept study to study the effect of split-belt treadmill training, designed to reduce step length asymmetry, on forward propulsion during walking. Eleven women with hip osteoarthritis and five age-matched control participants walked on an instrumented split-belt treadmill at their preferred speed (hip osteoarthritis: 0.73 ± 0.11 m/s; controls: 0.59 ± 0.26 m/s). Women with hip osteoarthritis had less ankle power and propulsive force than controls, and greater hip contributions to forward propulsion on their involved limb. Following split-belt treadmill training, propulsive force increased on the involved limb. Five of 11 participants experienced a change in redistribution ratio that was greater than the minimal clinically meaningful difference. These "responders" had greater variability in pre-training redistribution ratio compared to non-responders. Women with hip osteoarthritis had poorer propulsive gait mechanics than controls yet split-belt treadmill training improved propulsive force. Redistribution ratio also changed in participants with high baseline variability. Our results suggest that split-belt treadmill training may be beneficial to people with hip osteoarthritis who have high variability in walking parameters. Further, the age-related shift to increased hip contributions to propulsion across populations of older adults may be due to increased variability during walking.

Mobility Requirements and Joint Loading during Straight Walking and 90° Turns in Healthy Older People and Those with Hip Osteoarthritis

Background/Objectives: Hip mobility and joint loading in hip osteoarthritis (HOA) patients are mostly assessed during straight walking. Yet, mobility limitations in the frontal and transverse planes are rarely found during this task in subjects with mild-to-moderate symptoms. Turning movements are frequently encountered during everyday life and might require larger hip mobility compared to straight walking, especially in the frontal and transverse planes. Thus, hip mobility and hip loading during straight walking and 90° turns in persons with HOA and healthy older adults were compared in this study. Methods: A retrospective analysis was conducted on 21 subjects with mild-to-moderate HOA and 21 healthy controls. Hip angles and moments were assessed during straight walking and 90° step and spin turns. Gait analysis was conducted using a motion capture system and a force plate. Group and movement task differences were assessed with a mixed-model ANOVA. Results: Peak abduction and adduction angles were largest during the step and spin turn, respectively, as were the group differences between HOA subjects and healthy subjects. Both turns require a greater transverse hip range of motion compared to straight walking. Limitations in transverse hip mobility in the HOA group were especially prominent during the step turn. Both turns cause higher joint moments than straight walking. Conclusions: The additional inclusion of 90° step and spin turns into gait analysis can enhance early identification of hip mobility limitations in the frontal and transverse planes in subjects with mild-to-moderate hip osteoarthritis. Early diagnosis is crucial for the timely application of conservative treatment strategies.

Comparative Efficacy of Various Exercise Therapies and Combined Treatments on Inflammatory Biomarkers and Morphological Measures of Skeletal Muscle among Older Adults with Knee Osteoarthritis: A Network Meta-Analysis

Osteoarthritis is associated with high risks of sarcopenia in older populations. Exercise interventions are promising treatments for musculoskeletal impairments in knee osteoarthritis (KOA). The purpose of this study was to identify the comparative effects of exercise monotherapy and its adjunct treatments on muscle volume and serum inflammation for older individuals with KOA. A literature search in the electronic databases was comprehensively performed from this study's inception until April 2024 to identify relevant randomized controlled trials (RCTs) that reported muscle morphology and inflammation outcomes after exercise. The included RCTs were analyzed through a frequentist network meta-analysis (NMA). The standard mean difference (SMD) with a 95% confidence interval was estimated for treatment effects on muscle morphology and inflammation biomarkers. The relative effects on each main outcome among all treatment arms were compared using surface under the cumulative ranking (SUCRA) scores. The certainty of evidence (CoE) was assessed by the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) ranking system. Probable moderators of the treatment efficacy were investigated by network meta-regression analysis. This study included 52 RCTs (4255 patients) for NMA. Among the 27 identified treatment arms, isokinetic training plus physical modality as well as low-load resistance training plus blood-flow restriction yielded the most optimal treatment for inflammation reduction (-1.89; SUCRA = 0.97; CoE = high) and muscle hypertrophy (SMD = 1.28; SUCRA = 0.94; CoE = high). The patient's age (β = -0.73), the intervention time (β = -0.45), and the follow-up duration (β = -0.47) were identified as significant determinants of treatment efficacy on muscle hypertrophy. Exercise therapy in combination with noninvasive agents exert additional effects on inflammation reduction and muscle hypertrophy compared to its corresponding monotherapies for the KOA population. However, such treatment efficacy is likely moderated by the patient's age, the intervention time, and the follow-up duration.

Association of mid-thigh quadriceps muscle quality with postoperative outcomes in patients with hip osteoarthritis undergoing total hip arthroplasty: a retrospective cohort study

PURPOSE

Muscle quality is more important than muscle mass for assessing physical function. Computed tomography (CT) is used to evaluate intramuscular fatty infiltration. The mid-thigh quadriceps CT attenuation values (CTV) expressed in Hounsfield units (HU) negatively correlate with physical function. Patients with hip osteoarthritis (HOA) have lower extremity muscle atrophy, including decreased cross-sectional area (CSA), CTV, and muscle strength. Using preoperative CT images, we investigated the association between mid-thigh quadriceps CSA, CTV, and postoperative outcomes in patients with HOA.

METHODS

This study included 62 patients who had unilateral HOA (62 hips) and underwent total hip arthroplasty (THA). We investigated the association between preoperative and postoperative Japanese Orthopaedic Association (JOA) hip scores, 12-item Short Form survey (SF-12), mid-thigh quadriceps CSA, and CTV.

RESULTS

The mean age was 64.7 ± 10.1 years, with 15 men (24.2%), and the mean body mass index was 24.3 ± 4.3 kg/m2. Secondary HOA was present in 79.0% of patients. The mean CSA and CTV of the mid-thigh quadriceps on the operative side were 38.8 ± 9.8 cm2 and 40.3 ± 7.8 HU, respectively. Multiple regression analyses adjusted for age and sex showed that preoperative mid-thigh quadriceps CSA was not associated with preoperative and postoperative JOA hip scores or SF-12. The preoperative mid-thigh quadriceps CTV was associated with the postoperative JOA hip score in the gait ability domain and SF-12 in the physical component summary domain.

CONCLUSION

Preoperative muscle quality is associated with postoperative outcomes in patients who have HOA regardless of age and sex.

Are the Effects of Resistance Exercise on Pain and Function in Knee and Hip Osteoarthritis Dependent on Exercise Volume, Duration, and Adherence? A Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of this study was to determine dose parameters for resistance exercise associated with improvements in pain and physical function in knee and hip osteoarthritis (OA) and whether these improvements were related to adherence.

METHODS

We searched six databases, from inception to January 28, 2023, for randomized controlled trials comparing land-based, resistance exercise-only interventions with no intervention, or any other intervention. There were four subgroups of intervention duration: 0 to <3 months, 3 to 6 months, >6 to <12 months, ≥12 months. The between-group effect was calculated for immediate postintervention pain and physical function (activities of daily living [ADL] and sports/recreation [SPORT]).

RESULTS

For both knee and hip, data from 280 studies showed moderate benefit for pain, physical function ADL, and physical function SPORT in favor of interventions 3 to 6 months. For the knee, there was also a moderate benefit for physical function ADL in favor of interventions >6 to <12 months. From 151 knee and hip studies that provided total exercise volume data (frequency, time, duration), there was no association between volume with the effect size for pain and physical function. A total of 74 studies (69 knee, 5 hip) reported usable adherence data. There was no association between adherence with the effect size for pain and physical function.

CONCLUSION

In knee and hip OA, resistance exercise interventions 3 to 6 months (and for the knee >6 to <12 months) duration improve pain and physical function. Improvements do not depend on exercise volume or adherence, suggesting exercise does not require rigid adherence to a specific dose.

Muscle and joint mechanics during maximum force biting following total temporomandibular joint replacement surgery

Total temporomandibular joint replacement (TMJR) surgery is the established treatment for severe temporomandibular joint disorders. While TMJR surgery is known to increase mouth-opening capacity, reduce pain and improve quality of life, little is known about post-surgical jaw function during activities of daily living such as biting and chewing. The aim of this study was to use subject-specific 3D bite force measurements to evaluate the magnitude and direction of joint loading in unilateral total TMJR patients and compare these data to those in healthy control subjects. An optoelectronic tracking system was used to measure jaw kinematics while biting a rubber sample for 5 unilateral total TMJR patients and 8 controls. Finite element simulations driven by the measured kinematics were employed to calculate the resultant bite force generated when compressing the rubber between teeth during biting tasks. Subject-specific musculoskeletal models were subsequently used to calculate muscle and TMJ loading. Unilateral total TMJR patients generated a bite force of 249.6 ± 24.4 N and 164.2 ± 62.3 N when biting on the contralateral and ipsilateral molars, respectively. In contrast, controls generated a bite force of 317.1 ± 206.6 N. Unilateral total TMJR patients biting on the contralateral molars had a significantly higher lateral TMJ force direction (median difference: 63.6°, p = 0.028) and a significantly lower ratio of working TMJ force to bite force (median difference: 0.17, p = 0.049) than controls. Results of this study may guide TMJ prosthesis design and evaluation of dental implants.

Balancing act: Unraveling the link between muscle strength, proprioception, and stability in unilateral hip osteoarthritis

The objectives of this study are to compare hip muscle strength, hip joint proprioception, and functional balance between individuals with unilateral hip OA and asymptomatic individuals and to examine the relationships among these variables in the hip OA population. In a prospective cross-sectional study, 122 participants (unilateral Hip OA: n = 56, asymptomatic: n = 56) were assessed at the CAMS/KKU musculoskeletal Physical Therapy laboratory. Ethical standards were upheld throughout the research, with informed consent obtained. Hip muscle strength was measured using a hand-held dynamometer, hip joint proprioception with a digital inclinometer, and functional balance using the Berg Balance Scale (BBS) and Timed Up and Go (TUG) test. Hip OA individuals exhibited significantly lower muscle strength and proprioceptive accuracy, and poorer functional balance than controls (p < 0.003). Correlation analyses revealed a positive correlation between muscle strength and BBS scores (r = 0.38 to 0.42) and a negative correlation with TUG test times (r = -0.36 to -0.41). Hip joint reposition sense (JRS) in flexion showed a negative correlation with balance (r = -0.46), while JRS in abduction was positively correlated (r = 0.46). The study highlights the clinical importance of muscle strength and proprioception in functional balance among individuals with unilateral hip OA. The results support the incorporation of muscle strengthening and proprioceptive training in interventions to improve balance and mobility in this population.

Effects of Electromyographic Biofeedback-Assisted Exercise on Functional Recovery and Quality of Life in Patients after Total Hip Arthroplasty: A Randomized Controlled Trial

The goal of the trial was to examine the effects of adding electromyographic biofeedback (EMG-BF) to the conventional program of physiotherapy after total hip arthroplasty (THA) on functional recovery and quality of life. The trial was designed as a prospective, interventional, single-blinded randomized controlled study. Ninety patients were randomized into an experimental group (EG) (n = 45; mean age 63.9 ± 8.8) and control group (CG) (n = 45; mean age 63.9 ± 9). All patients received 21 days of physiotherapy which consisted of therapeutic exercise (land-based and aquatic), electrotherapy, and education. Electromyographic biofeedback was added to a portion of the land-based exercise in EG. The Hip Disability and Osteoarthritis Outcome Score (HOOS), Numeric Rating Scale (NRS), Short Form Health Survey-36 (SF-36), use of a walking aid, 30 s chair stand test (CST) as well as the Timed Up and Go (TUG) test were used for outcome measurement. A higher proportion of the participants in both groups did not need a walking aid after the intervention (p < 0.05). All participants improved their 30 s CST and TUG results (p < 0.001), as well as their NRS and HOOS scores (p < 0.05). No significant differences between the groups were found. There were no additional benefits from adding EMG-BF to the conventional physiotherapy protocol.

Comparison of postoperative isokinetic quadriceps and gluteal muscular strength after primary THA: is there an early benefit through enhanced recovery programs?

PURPOSE

Although total hip arthroplasty (THA) is expected to result in a postoperative loss of muscular strength, no study investigated the benefit of an enhanced-recovery-after-surgery (ERAS) concept on the hip muscles in detail. We evaluated if (1) an ERAS-concept for primary THA results in reduced loss of muscular strength five days and four weeks postoperative. We (2) compared the two groups regarding Patient-Related-Outcome-Measures (PROMs), WOMAC-index (Western-Ontario-and-McMaster-Universities-Osteoarthritis-Index), HHS (Harris-Hip-Score) and EQ-5d-3L-score.

METHODS

In a prospective, single-blinded, randomized controlled trial, we compared isokinetic muscular strength of 24 patients receiving primary THA with an enhanced recovery concept with early mobilization (n = 12, ERAS-group) and such receiving conventional THA (n = 12, non-ERAS). Isokinetic muscular strength was measured with a Biodex-Dynamometer before, as well as five days and four weeks after surgery (peak-torque, total-work, power). Furthermore, WOMAC, HHS, PROMs and EQ-5d-3L were imposed.

RESULTS

The ERAS group revealed significant higher isokinetic strength (peak-torque, total-work, power) at both time points. Both groups showed a significant pain decrease at both time points meeting very high rates of patient satisfaction resembled by good results in PROMs, WOMAC, HHS, EQ-5d. There was no significant difference in any of the scores between both groups.

CONCLUSION

We proved a significant reduced loss of muscular strength five days and four weeks after primary THA in combination with an ERAS concept. However, the reduced loss of muscular strength is not reflected by patient's functional outcome and quality of life, showing no significant differences in WOMAC, HHS, EQ-5d-3L, PROMs and NRS. Therefore, this study supports the implementation of an ERAS concept for primary THA in terms of isokinetic strength. Further studies are needed to evaluate the development of muscular strength over a long period.

Identifying Muscle Function-based Phenotypes Associated With Radiographic Progression of Secondary Hip Osteoarthritis

OBJECTIVE

The purposes of our study were to (1) identify muscle function-based clinical phenotypes in patients with hip osteoarthritis (OA) and (2) determine the association between those phenotypes and radiographic progression of hip OA.

DESIGN

Prospective cohort study.

SETTING

Clinical biomechanics laboratory of a university.

PARTICIPANTS

Fifty women patients with mild-to-moderate secondary hip OA (N=50) were recruited from the orthopedic department of a single institution.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Two-step cluster analyses were performed to classify the patients, using hip flexion, extension, abduction, and external/internal rotation muscle strength (cluster analysis 1); relative hip muscle strength to total hip strength (ie, hip muscle strength balance; cluster analysis 2); and both hip muscle strength and muscle strength balance (cluster analysis 3) as variables. The association between the phenotype and hip OA progression over 12 months (indicated by joint space width [JSW] >0.5 mm) was investigated by logistic regression analyses. Hip joint morphology, hip pain, gait speed, physical activity, Harris hip score, and SF-36 scores were compared between the phenotypes.

RESULTS

Radiographic progression of hip OA was observed in 42% of the patients. The patients were classified into 2 phenotypes in each of the 3 cluster analyses. The solution in cluster analyses 1 and 3 was similar, and high-function and low-function phenotypes were identified; however, no association was found between the phenotypes and hip OA progression. The phenotype 2-1 (high-risk phenotype) extracted in cluster analysis 2, which had relative muscle weakness in hip flexion and internal rotation, was associated with subsequent hip OA progression, even after adjusting for age and minimum JSW at baseline (adjusted odds ratio [95% confidence interval], 3.60 [1.07-12.05]; P=.039).

CONCLUSION

As preliminary findings, the phenotype based on hip muscle strength balance, rather than hip muscle strength, may be associated with hip OA progression.

Protocol for a randomised feasibility trial comparing a combined program of education and exercise versus general advice for ankle osteoarthritis

BACKGROUND

Ankle osteoarthritis (OA) is a serious problem with high associated pain and disability. While education and exercise are recommended for the initial management of OA, this has not been investigated in ankle OA. The primary aim of this study is to establish the feasibility of running a full-scale randomised controlled trial (RCT) investigating a combined education and exercise program compared to a general advice program for people with ankle OA. The secondary aims are to collect preliminary data which will inform sample size calculations, and understand the perspectives of people with ankle OA on their participation in the trial.

METHODS

Thirty individuals aged 35 years or older with symptomatic radiographic ankle OA will be recruited from the community and randomised to receive either a combined education and exercise program or a general advice program, both of which will be delivered by a physiotherapist in a group setting. Primary outcomes of feasibility include responses to study advertisements, number of eligible participants, recruitment rate, adherence with the intervention, fidelity of the intervention, adverse events, drop-out rate, and credibility and expectancy of the intervention. Secondary participant-reported outcomes will include global rating of change, patient acceptable symptom state, severity of ankle pain and stiffness, self-reported function, quality of life, satisfaction with treatment, and use of co-interventions. Follow up will be at 8 weeks and 3 months. Physical measures of 40 m walking speed, timed stairs descent, heel raise endurance and ankle dorsiflexion range of motion will be collected at baseline and 8 weeks. Primary feasibility outcomes will be reported descriptively, and estimates of the variability of secondary participant-reported and physical outcomes will be calculated. Semi-structured interviews will be conducted with participants to understand perspectives about the intervention and participation in the trial, with data analyzed thematically.

DISCUSSION

Study findings will establish the feasibility of running a full-scale RCT to investigate a combined education and exercise program compared to a general advice program for people with ankle OA. This study is a necessary first step to advance the international research agenda of evaluating the efficacy of exercise in the management of ankle OA.

TRIAL REGISTRATION

ACTRN12623000017628. Registered 10 January 2023, https://www.anzctr.org.au/ACTRN12623000017628.aspx .

Individual muscle contributions to the acceleration of the centre of mass during gait in people with mild-to-moderate hip osteoarthritis

BACKGROUND

People with mild-to-moderate hip osteoarthritis (OA) exhibit hip muscle weakness, alterations in hip kinematics and kinetics and hip contact forces during gait compared to healthy controls. However, it is unclear if those with hip OA use different motor control strategies to coordinate the motion of the centre of mass (COM) during gait. Such information could provide further critical assessment of conservative management strategies implemented for people with hip OA.

RESEARCH QUESTION

Do muscle contributions to the acceleration of the COM during walking differ between individuals with mild-to-moderate hip OA and controls?

METHODS

Eleven individuals with mild-to-moderate hip OA and 10 healthy controls walked at a self-selected speed while whole-body motion and ground reaction forces were measured. Muscle forces during gait were obtained using static optimisation and an induced acceleration analysis was performed to determine individual muscle contributions to the acceleration of the COM during single-leg stance (SLS). Between-group comparisons were made using independent t-tests via Statistical Parametric Modelling.

RESULTS

There were no between-group differences in spatial-temporal gait parameters or three-dimensional whole-body COM acceleration. The rectus femoris, biceps femoris, iliopsoas and gastrocnemius muscles in the hip OA group contributed less to the fore-aft accelerations of the COM (p < 0.05), and more to the vertical COM acceleration with the gluteus maximus (p < 0.05), during SLS, compared to the control group.

SIGNIFICANCE

Subtle differences exist in the way people with mild-to-moderate hip OA use their muscles to accelerate the whole-body centre of mass during the SLS phase of walking relative to healthy controls. These findings improve understanding of the complex functional consequences of hip OA and enhance our understanding of how to monitor the effectiveness of an intervention on biomechanical changes in gait in people with hip OA.

Intra- and inter-rater reliability, agreement, and minimal detectable change of the handheld dynamometer in individuals with symptomatic hip osteoarthritis

INTRODUCTION

The handheld dynamometer has been validated to measure muscle strength in different muscle groups. However, to date, it has not been tested in individuals who experience pain induced by hip osteoarthritis. The current study aimed to evaluate the intra- and inter-rater reliability, agreement, and minimal detectable change of the Lafayette handheld dynamometer, model 1165, to assess the peak force (Pk) and average peak force (Af) of hip muscles in individuals with symptomatic hip osteoarthritis.

METHODS

Twenty participants with hip osteoarthritis (mean ± SD age: 58.7±15.3 years; body mass index: 28.8±4.2 kg/m2) and pain intensity on the Visual Analogue Scale ≥ 4 (8.05±1.2) were recruited to participate in this study. Pk and Af of hip flexors (seated position), abductors and adductors (supine position), and extensors (prone position) were collected in a single day by two independent raters, each one obtaining test and retest in randomly ordered separate sessions.

RESULTS

The intra-rater intraclass correlation coefficient (ICC) was classified as good (>0.75) or excellent (≥0.90) for all muscle groups and all inter-rater ICCs were classified as excellent. Rater A had a lower standard error of measurement compared to rater B, ranging from 0.15 to 0.58 kilogram-force (Kgf) compared with 0.34 to 1.25 kg, respectively. However, the inter-rater comparison showed a minimal detectable change (MDC) of < 10% for all Pk and Af measures for hip adductors and extensors. Finally, the inter-rater Bland-Altman analysis demonstrated good agreement for abductors, adductors, and extensors.

CONCLUSION

Despite pain and dysfunction related to hip osteoarthritis, the mean of two measures using a handheld dynamometer was shown to be a reliable tool to assess hip muscle strength, with good to excellent intra- and inter-rater ICCs, satisfactory agreement, and small values for MDC.

Magnetic resonance-based hip muscles retrospective analysis shows deconditioning and recovery after total hip arthroplasty surgery

PURPOSE

The purpose of this study is to estimate the effect of unilateral hip osteoarthritis (OA) on hip muscle volume and fatty infiltration and to evaluate changes of muscles after total hip arthroplasty (THA) surgery.

METHODS

A retrospective analysis was conducted on patients with unilateral hip OA subjected to THA with perioperative pelvic girdle 1.5 T magnetic resonance imaging (MRI). Thirty-five patients were included. Ten of these have also postoperative MRIs. Medius gluteus (MG) and iliopsoas (IP) muscles were manually segmented on the MRI scans, the corresponding 3D muscle geometries were reconstructed, and the volumes extracted. Muscle quality was assessed using the Goutallier classification on coronal MRI images. Volume and muscle quality differences were calculated between healthy and affected side.

RESULTS

Pre-operatively, MG and IP on the affected side presented a mean muscle volume 17.5 ± 18% (p < 0.001) and 14.4 ± 15.8% (p < 0.001) smaller than the healthy counterpart, respectively. Muscles on the affected side showed a significant higher grade of fatty infiltration compared to the healthy side (p < 0.05 for MG; p < 0.001 for IP). At an average follow-up of 13 ± 5.3 months after THA, MG, and IP muscles of the affected hip showed an average 22.8% (p < 0.001) and 28.2% (p < 0.001) volume increase after THA. Also, the healthy side showed a significant increase of muscle volume for IP (17.1% p < 0.001). No significant change for MG muscle was observed.

CONCLUSIONS

The study demonstrated preoperative reduced muscle volume and higher fatty infiltration at the muscles of the OA hip compared to the contralateral healthy one. A significant positive effect of THA on hip muscle volume was observed. These findings give an interesting insight on muscle deconditioning and recovery in patients undergoing THA.

Segmental bioelectrical impedance analysis can detect differences between the affected and non-affected limbs in individuals with hip osteoarthritis

OBJECTIVE

To analyze the bioelectrical impedance parameters of the lower limbs of individuals with hip osteoarthritis and healthy individuals.

DESIGN

Cross-sectional study.

SETTING

The study was carried out at the Hip Surgery Outpatient Clinic.

PARTICIPANTS

The volunteers had to be between 45 and 70 years of age, of both sexes, with a clinical and radiological diagnosis of hip osteoarthritis for at least three years, unilateral involvement, or a significant complaint in one hip.

METHODS

This was a cross-sectional study. Fifty-four individuals were recruited for the study, 31 individuals with hip osteoarthritis (OA group) and 29 healthy individuals for the control group (C group). Demographic and anthropometric data were collected and then the Numerical Pain Rating Scale, WOMAC, Harris Hip Score, and bioimpedance assessment were applied.

MAIN OUTCOME MEASURE(S)

Electrical bioimpedance parameters. Phase angle (PhA), impedance, reactance, and muscle mass.

RESULTS

There was a significant difference in phase angle (PhA), impedance, and muscle mass at 50 kHz frequency on the side affected by OA when compared to the contralateral side. In the OA group, there was a significant decrease in phase angle (PhA) -0.54 (-0.85 to -0.23) and muscle mass - 0.29 (-0.40 to -0,19), as well as an increase in impedance at the 50 kHz frequency on the side affected by OA when compared to contralateral side 21.71 (13.69 to 29.74). In the C group, there was no difference between the dominant and non-dominant sides (P > 0.05).

CONCLUSION

The segmental electrical bioimpedance equipment can detect differences between limbs affected and unaffected by hip osteoarthritis.

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.

The complexity of decision-making for total hip arthroplasty in early osteoarthritis

Cite this article: Bone Joint Res 2023;12(5):306–308.

The influence of induced gait asymmetry on joint reaction forces

Chronic injury- or disease-induced joint impairments result in asymmetric gait deviations that may precipitate changes in joint loading associated with pain and osteoarthritis. Understanding the impact of gait deviations on joint reaction forces (JRFs) is challenging because of concurrent neurological and/or anatomical changes and because measuring JRFs requires medically invasive instrumented implants. Instead, we investigated the impact of joint motion limitations and induced asymmetry on JRFs by simulating data recorded as 8 unimpaired participants walked with bracing to unilaterally and bilaterally restrict ankle, knee, and simultaneous ankle + knee motion. Personalized models, calculated kinematics, and ground reaction forces (GRFs) were input into a computed muscle control tool to determine lower limb JRFs and simulated muscle activations guided by electromyography-driven timing constraints. Unilateral knee restriction increased GRF peak and loading rate ipsilaterally but peak values decreased contralaterally when compared to walking without joint restriction. GRF peak and loading rate increased with bilateral restriction compared to the contralateral limb of unilaterally restricted conditions. Despite changes in GRFs, JRFs were relatively unchanged due to reduced muscle forces during loading response. Thus, while joint restriction results in increased limb loading, reductions in muscle forces counteract changes in limb loading such that JRFs were relatively unchanged.

Artificial intelligence-based volumetric analysis of muscle atrophy and fatty degeneration in patients with hip osteoarthritis and its correlation with health-related quality of life

PURPOSE

Artificial intelligence (AI) technologies have enabled precise three-dimensional analysis of individual muscles on computed tomography (CT) or magnetic resonance images via automatic segmentation. This study aimed to perform three-dimensional assessments of pelvic and thigh muscle atrophy and fatty degeneration in patients with unilateral hip osteoarthritis using CT and to evaluate the correlation with health-related quality of life (HRQoL).

METHODS

The study included one man and 43 women. Six muscle groups were segmented, and the muscle atrophy ratio was calculated volumetrically. The degree of fatty degeneration was defined as the difference between the mean CT values (Hounsfield units [HU]) of the healthy and affected sides. HRQoL was evaluated using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index and the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ).

RESULTS

The mean muscle atrophy rate was 16.3%, and the mean degree of muscle fatty degeneration was 7.9 HU. Multivariate correlation analysis revealed that the WOMAC stiffness subscale was significantly related to fatty degeneration of the hamstrings, the WOMAC physical function subscale was significantly related to fatty degeneration of the iliopsoas muscle, and the JHEQ movement subscale was significantly related to fatty degeneration of the hip adductors.

CONCLUSION

We found that fatty degeneration of the hamstrings, iliopsoas, and hip adductor muscles was significantly related to HRQoL in patients with hip osteoarthritis. These findings suggest that these muscles should be targeted during conservative rehabilitation for HOA and perioperative rehabilitation for THA.

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 a targeted resistance intervention compared to a sham intervention on gluteal muscle hypertrophy, fatty infiltration and strength in people with hip osteoarthritis: analysis of secondary outcomes from a randomised clinical trial

Background

People with hip osteoarthritis are typically offered a combination of education and exercise to address muscle atrophy and weakness. Limited evidence exists to assess the efficacy of exercise programs on muscle structure or function in this population. The aim of this study was to evaluate the effects of targeted resistance exercise on gluteal muscle hypertrophy and strength in people with mild-to-moderate hip osteoarthritis.

Methods

Twenty-seven participants with radiologically confirmed hip osteoarthritis recruited from a single site of a multi-site, double-blind clinical trial were randomly allocated to receive a 12-week targeted gluteal intervention or sham intervention. Magnetic resonance imaging and hand-held dynamometry were used to determine change in gluteal muscle volume, fatty infiltration and hip muscle strength. For gluteal muscle volume and strength outcomes mixed model analyses of variance (ANOVA) were conducted. A general linear model (ANOVA) analysis with fixed effects parameter estimates was used to assess the impact of sex on gluteal muscle size and strength of the affected limb only. For muscle fat index a mixed method ANOVA was used to assess the differences between groups and over time.

Results

In the targeted intervention group, gluteus minimus volume increased from baseline to post-intervention in both limbs (pooled mean difference: 0.06 cm³/kg, 95% confidence interval: 0.01 to 0.11) while no change occurred in the sham group (time x group effect: P = 0.025). Gluteus medius, gluteus maximus and tensor fascia lata volume did not change significantly over time. Hip strength (abduction, adduction, flexion, extension, external and internal rotation) improved similarly in both groups (time main effect: P ≤ 0.042). There was a consistent, albeit non-significant, pattern of reduced fatty infiltration after the targeted intervention.

Conclusion

Targeted resistance exercise resulted in gluteus minimus hypertrophy, but improvements in hip strength occurred in both groups. Clinicians delivering hip osteoarthritis rehabilitation programs might consider implementing a targeted exercise program to attenuate disease associated changes within gluteal muscles.

Trial registration

Australian New Zealand Clinical Trials Registry, ID: ACTRN12617000970347. Registered prospectively on 5 July 2017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05907-4.

The reliability of the measurement of muscle volume using magnetic resonance imaging in typically developing infants by two raters

To assess intra-rater and inter-rater reliability of the manual segmentation of Magnetic Resonance Imaging (MRI) for the in vivo measurement of infant muscle volume of the knee extensor and flexor muscles by two raters. Muscles of the knee extensor and flexor muscle of ten typically developing infants (86 days ± 7 days) were scanned with MRI (Proton density sequence). Scans were then segmented using Slicer software, and volumes rendered by two raters. Intra-rater and inter-rater reliability were assessed using intra-class correlation (ICC), with mean difference (MD), standard error of the mean (SEM), and minimal detectable change (MDC) for each muscle calculated. ICCs for Intra-rater reliability of the segmentation process for the muscle volume of the muscles of the knee extensors and flexor muscles were 0.901-0.972, and 0.776-0.945 respectively, with inter-rater reliabilities between 0.914-0.954 and 0.848-0.978, for the knee extensor and flexors muscles respectively. For intra-rater reliability, MD ≤ - 0.47 cm³, MDCs for were < 1.09 cm³ and for inter-rater MD ≤ - 1.40 cm³, MDCs for were < 1.63 cm³ for all muscles. MRI segmentation for muscle volumes showed good to excellent reliability, though given the small volumes of the muscles themselves, variations between raters are amplified. Care should be taken in the reporting and interpretation of infant muscle volume.

Prophylactic administration of miR-451 inhibitor decreases osteoarthritis severity in rats

Transfection of chondrocytes with microRNA-451(miR-451), present in growth zone cartilage of the growth plate, upregulates production of enzymes association with extracellular matrix degradation. miR-451 is also present in articular cartilage and exacerbates IL-1β effects in articular chondrocytes. Moreover, when osteoarthritis (OA) was induced in Sprague Dawley rats via bilateral anterior cruciate ligament transection (ACLT), miR-451 expression was increased in OA cartilage compared to control, suggesting its inhibition might be used to prevent or treat OA. To examine the prophylactic and therapeutic potential of inhibiting miR-451, we evaluated treatment with miR-451 power inhibitor (451-PI) at the onset of joint trauma and treatment after OA had developed. The prophylactic animal cohort received twice-weekly intra-articular injections of either 451-PI or a negative control (NC-PI) beginning on post-surgical day 3. OA was allowed to develop for 24 days in the therapeutic cohort before beginning injections. All rats were killed on day 45. Micro-CT, histomorphometrics, OARSI scoring, and muscle force testing were performed on samples. 451-PI mitigated OA progression compared to NC-PI limbs in the prophylactic cohort based on histomorphometric analysis and OARSI scoring, but no differences were detected by micro-CT. 451-PI treatment beginning 24 days post-surgery was not able to reduce OA severity. Prophylactic administration of 451-PI mitigates OA progression in a post-trauma ACLT rat model supporting its potential to prevent OA development following an ACLT injury clinically.

Effectiveness of Exercise in Patients with Overweight or Obesity Suffering from Knee Osteoarthritis: A Systematic Review and Meta-Analysis

OBJECTIVES

The main purpose of this study was to review the evidence about the effectiveness of exercise in patients with overweight or obesity suffering from knee osteoarthritis.

METHODS

Randomized clinical trials (RCTs) published between January 2002 and May 2022 were included.

RESULTS

A total of 64 articles were identified, of which six met the criteria for meta-analysis. The pain scale score was higher in the control group (mean difference 0.95; confidence interval 0.42-1.47; p < 0.001; I2 = 44%). The physical function scale (lower scores indicate lower levels of symptoms or physical disability) presented a higher score in the control group (mean difference 3.74; confidence interval 0.85-6.53; p < 0.05; I2 = 56%). Moreover, the intervention group achieved a greater distance (meters) walking in a 6 min interval (mean difference 38.18; confidence interval 20.01-56.35; p < 0.001; I2 = 0%).

CONCLUSIONS

Exercise interventions seem effective in improving quality of life in people with overweight or obesity suffering from knee osteoarthritis, reducing pain and improving physical function.

Association between sarcopenia and osteoarthritis: A protocol for meta-analysis

Background

Sarcopenia, a relatively new syndrome referring to the age-related decline of muscle strength and degenerative loss of skeletal muscle mass and function, often resulting in frailty, disability, and mortality. Osteoarthritis, as a prevalent joint degenerative disease, is affecting over 250 million patients worldwide, and it is the fifth leading cause of disability. Despite the high prevalence of osteoarthritis, there are still lack of efficient treatment potions in clinics, partially due to the heterogeneous and complexity of osteoarthritis pathology. Previous studies revealed the association between sarcopenia and osteoarthritis, but the conclusions remain controversial and the prevalence of sarcopenia within osteoarthritis patients still needs to be elucidated. To identify the current evidence on the prevalence of sarcopenia and its association with osteoarthritis across studies, we performed this systematic review and meta-analysis that would help us to further confirm the association between these two diseases.

Methods and analysis

Electronic sources including PubMed, Embase, and Web of Science will be searched systematically following appropriate strategies to identify relevant studies from inception up to 28 February 2022 with no language restriction. Two investigators will evaluate the preselected studies independently for inclusion, data extraction and quality assessment using a standardized protocol. Meta-analysis will be performed to pool the estimated effect using studies assessing an association between sarcopenia and osteoarthritis. Subgroup analyses will also be performed when data are sufficient. Heterogeneity and publication bias of included studies will be investigated.

PROSPERO registration number

CRD42020155694.

Neuromuscular Consequences of Lumbopelvic Dysfunction: Research and Clinical Perspectives

Injuries involving the lumbopelvic region (ie, lumbar spine, pelvis, hip) are common across the lifespan and include pathologies such as low back pain, femoroacetabular impingement syndrome, labrum tear, and osteoarthritis. Joint injury is known to result in an arthrogenic muscle response which contributes to muscle weakness and altered movement patterns. The purpose of this manuscript is to summarize the arthrogenic muscle response that occurs across lumbopelvic region pathologies, identify methods to quantify muscle function, and propose suggestions for future research. While each lumbopelvic region pathology is unique, there are a few common impairments and a relative consistent arthrogenic muscle response that occurs across the region. Hip muscle weakness and hip joint range of motion limitations occur with both lumbar spine and hip pathologies, and individuals with low back pain are known to demonstrate inhibition of the transversus abdominis and multifidus. Assessment of muscle inhibition is often limited to research laboratory settings, but dynamometers, ultrasound imaging, and electromyography offer clinical capacity to quantify muscle function and inform treatment pathways. Future studies should systematically determine the arthrogenic muscle response across multiple muscle groups and the timeline for changes in muscle function and determine whether disinhibitory modalities improve functional outcomes beyond traditional treatment approaches.

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.

Does Isolated Unilateral Hip or Knee Osteoarthritis Lead to Adverse Changes in Extremity Composition?

BACKGROUND

While muscle atrophy is a function of normal aging, loss of muscle in the setting of hip and knee osteoarthritis (OA) has been observed using radiographic studies. There is limited data available regarding changes in extremity composition using bioimpedance (BIA). The purpose of this study was to assess the changes in extremity composition in patients with isolated, unilateral hip or knee OA using BIA.

METHODS

Patients presenting to our institution's adult reconstruction clinic from February 2020 to April 2021 were retrospectively reviewed to identify those with isolated, unilateral hip and knee OA. The InBody 770 Body Composition Analyzer (InBody USA, Cerritos, California) was used to perform a complete body composition assessment, per protocol. Lean extremity mass (LEM), fat mass (FM), intracellular water (ICW), extremity body water (EBW = ICW + extracellular water (ECW)) and phase angle (PA) were determined. Differences between the affected (OA) and unaffected (no OA) extremities were compared using t-tests.

RESULTS

38 patients had isolated hip OA. The mean age was 60.8 (±11.7) years, mean BMI was 31.7 (±6.8) kg/m2, and 39.5% were female. LEM, FM, EBW, ICW, and PA were significantly decreased in the hip OA extremity (LEM: 20.0 vs. 20.4 kg, p=0.0008, FM: 8.8 vs. 8.9 kg, p=0.0049, EBW: 15.7 vs 16.0, p=0.0011, ICW: 9.5 vs. 9.7 L, p=0.0004, PA: 4.5 vs 4.9º, p<0.0001). There were 25 patients with isolated knee OA. Mean age was 62.8 (±11.3) years, mean BMI was 33.6 (±6.9) kg/m2, and 52.0% were female. FM and PA were significantly lower in the knee OA extremity (11.3 vs 11.4 kg, p=0.0291, 4.5 vs 4.9º, p<0.0001). There were no significant differences in LEM, EBW, and ICW between the knee OA extremity and the unaffected extremity.

CONCLUSION

Patients with isolated, unilateral hip OA had decreased LEM, FM, EBW, and ICW in the affected extremity. Both unilateral hip and knee OA was associated with decreased PA, suggestive of greater underlying dysfunction in muscle or cellular performance. Further study is needed to better define when these abnormalities develop, how they progress over time, and the impact of targeted interventions in reversing these changes. Level of Evidence: III.

Simulating Ideal Assistive Strategies to Reduce the Metabolic Cost of Walking in the Elderly

OBJECTIVE

Development of walking assist exoskeletons is a growing area of study, offering a solution to restore, maintain, and enhance mobility. However, applying this technology to the elderly is challenging and there is currently no consensus as to the optimal strategy for assisting elderly gait. The gait patterns of elderly individuals often differ from those of the younger population, primarily in the ankle and hip joints. This study used musculoskeletal simulations to predict how ankle and hip actuators might affect the energy expended by elderly participants during gait.

METHODS

OpenSim was used to generate simulations of 10 elderly participants walking at self-selected slow, comfortable, and fast speeds. Ideal flexion/extension assistive actuators were added bilaterally to the ankle or hip joints of the models to predict the maximum metabolic power that could be saved by exoskeletons that apply torques at these joints.

RESULTS

Compared to the unassisted scenario, the use of ideal hip actuators resulted in 215%, 265%, and 306% reductions in average metabolic power consumption at slow, comfortable, and fast walking speeds, respectively; use of ideal ankle actuators resulted in 123%, 142%, and 161% metabolic savings, respectively.

CONCLUSION

The simulations suggest that providing hip assistance to elderly individuals during walking can result in significantly greater metabolic savings than ankle assistance, assuming kinematics and total joint moments do not change substantially with assistance.

SIGNIFICANCE

The achieved research results and analysis provide exoskeleton developers guidance on optimally designing walking assist exoskeletons, thus promoting consensus toward the optimal strategy for assisting elderly individuals.

Metabolomic signatures for the longitudinal reduction of muscle strength over 10 years

Background

Skeletal muscles are essential components of the neuromuscular skeletal system that have an integral role in the structure and function of the synovial joints which are often affected by osteoarthritis (OA). The aim of this study was to identify the baseline metabolomic signatures for the longitudinal reduction of muscle strength over 10 years in the well-established community-based Tasmanian Older Adult Cohort (TASOAC).

Methods

Study participants were 50–79 year old individuals from the TASOAC. Hand grip, knee extension, and leg strength were measured at baseline, 2.6-, 5-, and 10-year follow-up points. Fasting serum samples were collected at 2.6-year follow-up point, and metabolomic profiling was performed using the TMIC Prime Metabolomics Profiling Assay. Generalized linear mixed effects model was used to identify metabolites that were associated with the reduction in muscle strength over 10 years after controlling for age, sex, and BMI. Significance level was defined at α=0.0004 after correction of multiple testing of 129 metabolites with Bonferroni method. Further, a genome-wide association study (GWAS) analysis was performed to explore if genetic factors account for the association between the identified metabolomic markers and the longitudinal reduction of muscle strength over 10 years.

Results

A total of 409 older adults (50% of them females) were included. The mean age was 60.93±6.50 years, and mean BMI was 27.12±4.18 kg/m² at baseline. Muscle strength declined by 0.09 psi, 0.02 kg, and 2.57 kg per year for hand grip, knee extension, and leg strength, respectively. Among the 143 metabolites measured, 129 passed the quality checks and were included in the analysis. We found that the elevated blood level of asymmetric dimethylarginine (ADMA) was associated with the reduction in hand grip (p=0.0003) and knee extension strength (p=0.008) over 10 years. GWAS analysis found that a SNP rs1125718 adjacent to WISP1gene was associated with ADMA levels (p=4.39*10^-8). Further, we found that the increased serum concentration of uric acid was significantly associated with the decline in leg strength over 10 years (p=0.0001).

Conclusion

Our results demonstrated that elevated serum ADMA and uric acid at baseline were associated with age-dependent muscle strength reduction. They might be novel targets to prevent muscle strength loss over time.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13395-022-00286-9.

Recovery of Muscle Atrophy and Fatty Infiltration in Patients With Acetabular Dysplasia After Total Hip Arthroplasty

INTRODUCTION

Hip osteoarthritis (OA) with acetabular dysplasia negatively affects pelvic alignment and muscle function. We aimed to investigate the changes in muscle atrophy and fatty infiltration of the hip and trunk muscles 1 year after total hip arthroplasty (THA) in patients with hip OA with acetabular dysplasia.

METHODS

This study included 51 female patients who underwent THA for unilateral hip OA with acetabular dysplasia. The cross-sectional area (CSA) and muscle density of the gluteus maximus, gluteus medius, gluteus minimus, piriformis, iliopsoas, rectus abdominis, and abdominal oblique muscles using computer tomography and pelvic inclination angle using radiographs were assessed before and 1 year after THA.

RESULTS

At the 1-year follow-up, the CSA and muscle density of the gluteus medius (2,078 to 2,522 mm2 and 30.3 to 39.4 hounsfield units [HU]), iliopsoas (715 to 901 mm2 and 40.3 to 50.8 HU), and rectus abdominis (336 to 363 mm2 and 28.6 to 30.6 HU) of the affected limb had increased significantly (P < 0.05). The CSA and muscle density of the gluteus maximus (2,429 versus 2,884 mm2 and 23.7 versus 32.6 HU), gluteus minimus (636 versus 785 mm2 and 14.3 versus 37.1 HU), piriformis (505 versus 607 mm2 and 23.4 versus 31.6 HU), and iliopsoas (901 versus 997 mm2 and 50.8 versus 54.5 HU) in the affected limb were lower than those in the unaffected limb (P < 0.01). Postoperatively, the CSA and muscle density of the rectus abdominis were not significantly different between the limbs, and the pelvic inclination angle (35.2° to 32.1°, P < 0.01) was significantly decreased.

DISCUSSION

Compared with the nonoperated limb, substantial atrophy and fatty infiltration of most hip muscles persisted in the operated limb 1 year after THA in patients with acetabular dysplasia; asymmetry in the rectus abdominis muscle fully resolved. In patients with acetabular dysplasia, the surgical technique and postoperative rehabilitation should be further considered to optimize hip muscle recovery.

Biomechanics of Cam Femoroacetabular Impingement: A Systematic Review

PURPOSE

To assess how biomechanical gait parameters (kinematics, kinetics, and muscle force estimations) differ between patients with cam-type femoroacetabular impingement (FAI) and healthy controls, through a systematic search.

METHODS

A systematic review of the literature from PubMed, Scopus, and Medline and EMBASE via OVID SP was undertaken from inception to April 2020 using PRISMA guidelines. Studies that described kinematics, kinetics, and/or estimated muscle forces in cam-type FAI were identified and reviewed.

RESULTS

The search strategy identified 404 articles for evaluation. Removal of duplicates and screening of titles and abstracts resulted in full-text review of 37 articles, with 12 meeting inclusion criteria. The 12 studies reported biomechanical data on a total of 173 cam-FAI (151 cam-specific, 22 mixed-type) patients and 177 healthy age-, sex-, and body mass index-matched controls. Patients with cam FAI had reduced hip sagittal plane range of motion (mean difference -3.00° [-4.10, -1.90], P < .001), reduced hip peak extension angles (mean difference -2.05° [-3.58, -0.53] , P = .008), reduced abduction angles in the terminal phase of stance, and reduced iliacus and psoas muscle force production in the terminal phase of stance compared to the control groups. Cam FAI cohorts walked at a slower speed compared with controls.

CONCLUSIONS

In conclusion, patients with cam-type FAI exhibit altered sagittal and frontal plane kinematics as well as altered muscle force production during level gait compared to controls. These findings will help guide future research into gait alterations in FAI and how such alterations may contribute to pathologic progression and furthermore, how such alterations can be modified for therapeutic benefit.

LEVEL OF EVIDENCE

Systematic review of Level III studies.

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.

Rehabilitation after a Complete Avulsion of the Proximal Rectus Femoris Muscle: Considerations from a Case Report

BACKGROUND

A complete avulsion of the proximal rectus femoris muscle is a rare but severity injury. There is a lack of substantial information for its operative treatment and rehabilitation; in particular there is a lack of biomechanical data to evaluate long-term outcomes.

CASE PRESENTATION

The case report presents the injury mechanism and surgical treatment of a complete avulsion of the proximal rectus femoris muscle in a 41-year-old recreational endurance athlete. Moreover, within a one-year follow-up period, different biomechanical tests were performed to get more functional insights into changes in neuromuscular control, structural muscle characteristics, and endurance performance. Within the first month post-surgery, an almost total neuromuscular inhibition of the rectus femoris muscle was present. A stepwise reduction in inter-limb compensations was observable (e.g., in crank torque during cycling) during the rehabilitation. Muscular intra-limb compensations were shown at six months post-surgery and even one year after surgery, which were also represented in the long-term adaption of the muscle characteristics and leg volumes. A changed motor control strategy was shown by asymmetric muscle activation patterns during ergometer cycling, while the power output was almost symmetric. During rehabilitation, there might be a benefit to normalizing neuromuscular muscle activation in ergometer cycling using higher loads.

CONCLUSIONS

While the endurance performance recovered after six months, asymmetries in neuromuscular control and structural muscle characteristics indicate the long-term presence of inter- and intra-limb compensation strategies.

Relationship between single-leg stance test with light touch and hip muscle strength in healthy young adults

[Purpose] This study investigated the relationship between the single-leg stance test with light touch and hip rotator muscle strength. [Participants and Methods] Thirty-one healthy young adults participated in the study. A single leg stance test with light touch was performed to evaluate the participants’ static balance ability. The duration that an individual could successfully perform the single leg stance test with light touch in the eyes open was measured. The participants were instructed to slightly touch their right index fingertip on the digital scale. The hip muscle strength of the internal rotators and external rotators were measured by the isometric peak torque. The internal/external rotator strength ratio was calculated by dividing the strength of the internal rotator by that of the external rotator. [Results] The hip external rotator muscle strength was higher in males than in females. Moreover, there was a significant correlation between the single-leg stance test with light touch and hip external rotator muscle strength in males and between the single leg stance test with light touch and hip internal rotator muscle strength in females. Furthermore, a significant positive correlation was found between the single leg stance test with light touch and hip internal rotator/external rotator ratio in males. [Conclusion] We concluded that the single leg stance test with light touch is a useful tool to evaluate static hip muscle strength.

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.

Effects of step length and cadence on hip moment impulse in the frontal plane during the stance phase

Background

An excessive daily cumulative hip moment in the frontal plane (determined as the product of hip moment impulse in the frontal plane during the stance phase and mean number of steps per day) is a risk factor for the progression of hip osteoarthritis. Moreover, walking speed and step length decrease, whereas cadence increases in patients with hip osteoarthritis. However, the effects of step length and cadence on hip moment impulse in the frontal plane during the stance phase are not known. Therefore, this study aimed to examine the effects of step length and cadence on hip moment impulse in the frontal plane during the stance phase.

Methods

We used a public dataset (kinetic and kinematic data) of over-ground walking and selected 31 participants randomly from the full dataset of 57 participants. The selected participants walked at a self-selected speed and repeated the exercise 15 times. We analyzed the data for all 15 trials for each participant. Multiple regression analysis was performed with the hip moment impulse in the frontal plane during the stance phase as the dependent variable and step length and cadence as independent variables.

Results

The adjusted R² in this model was 0.71 (p < 0.001). The standardized partial regression coefficients of step length and cadence were 0.63 (t = 5.24; p < 0.001) and −0.60 (t =  − 4.58; p < 0.001), respectively.

Conclusions

Our results suggest that low cadence, not short step length, increases the hip moment impulse in the frontal plane. Our findings help understand the gait pattern with low hip moment impulse in the frontal plane.

Effects of Protein-Rich Nutritional Composition Supplementation on Sarcopenia Indices and Physical Activity during Resistance Exercise Training in Older Women with Knee Osteoarthritis

Older adults with knee osteoarthritis (KOA) are at high risk of sarcopenia. Protein-rich nutritional composition supplementation (PS) combined with resistance exercise training (RET) improves muscle gains and facilitates physical activity in older adults. However, whether PS augments the effects of RET on muscle mass and PA in patients with KOA remains unclear. Therefore, this study identified the effects of PS on sarcopenic indices and PA in older women with KOA subjected to an RET program. Eligible older women aged 60–85 years and diagnosed as having KOA were randomly assigned to either the experimental group (EG) or the control group (CG). Both groups performed RET twice a week for 12 weeks. The EG received additional PS during this period. Outcome measures included appendicular lean mass index, walking speed, physical activity, and scores on the Western Ontario and McMaster Universities Osteoarthritis Index—WOMAC). All measures were tested at baseline and after intervention. With participant characteristics and baseline scores as covariates, analysis of variance was performed to identify between-group differences in changes in all outcome measures after intervention. Statistical significance was defined as p < 0.05. Compared with the CG, the EG achieved greater changes in appendicular lean mass index (adjusted mean difference (aMD) = 0.19 kg/m², p < 0.01), physical activity (aMD = 30.0 MET-hour/week, p < 0.001), walking speed (aMD = 0.09 m/s, p < 0.05), and WOMAC global function (aMD = −8.21, p < 0.001) after intervention. In conclusion, PS exerted augmentative effects on sarcopenic indices, physical activity, and perceived global WOMAC score in older women with KOA through 12 weeks of RET.

Strength and endurance deficits in adults with moderate-to-severe hip osteoarthritis, compared to healthy, older adults

PURPOSE

This study compares lower limb muscle strength and endurance in adults with hip osteoarthritis, to an age-matched control group.

METHODS

Thirteen adults with moderate-to-severe hip osteoarthritis (as graded by the Oxford Hip Score) and fifteen older adults participated. Maximal voluntary isometric contraction of the knee extensors, knee flexors and hip abductors and isotonic endurance of the knee extensors were measured using a dynamometer. Function was assessed using the 30-second chair stand test, the 40 m fast-paced walk test and a stair negotiation test. Data were compared between groups using t-tests.

RESULTS

Participants with hip osteoarthritis demonstrated weakness in the affected limb when compared to the control limb during knee flexion (34%, p = 0.004) and hip abduction (46%, p = 0.001). Weakness was also observed in the contralateral knee flexors (31%, p = 0.01). When compared to the control limb, the knee extensors of the hip osteoarthritis group were exhausted prematurely in the affected (70%, p = 0.001) and contralateral limb (62%, p = 0.005). The hip osteoarthritis group took twice as long to stair climb (p = 0.002), walked 40% slower, (p < 0.001), and had a 35% lower sit-stand performance (p < 0.001).

CONCLUSIONS

Moderate-to-severe hip osteoarthritis may be characterised by bilateral deficits in lower-limb maximal strength, markedly lower knee extensor endurance and impaired functional performance.Implications for rehabilitationIn addition to bilateral deficits in maximal strength of the hip and knee muscles, moderate-to-severe hip osteoarthritis may be characterised by markedly lower muscular endurance of the knee extensors and impaired functional performance.The endurance capacity of the knee extensors can play an important role in daily function, and thus it is important to consider endurance training principles when prescribing exercise for this patient group.Research studies evaluating exercise programmes underpinned by endurance training principles are required to understand the benefits to patients with hip osteoarthritis, and to inform specific exercise prescription in clinical practice.

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.

Could the Evaluation of Muscle Strength Imbalances Be Used as a Predictor of Total Hip Arthroplasty?

Loss of muscle strength characterizes the period before total hip arthroplasty (THA). Little is known about whether muscle strength imbalances caused by muscle strength decline could be considered another clinical predictor for THA. This study aimed to determine whether muscle imbalances may be used as a clinical predictor for THA surgery. Thirty-six participants were enrolled in the study. Eighteen patients had THA (THA group), while 18 were healthy elders (CON group). Ipsilateral (H/Q) and bilateral (% Def) muscle imbalances of the knee were assessed. THA patients showed impairment of the extensors on the affected extremity compared to those unaffected. A comparison between the groups proved there were weakened flexors in the THA group on both extremities. A comparison of the imbalances revealed a significant bilateral imbalance of the extensors and ipsilateral imbalance of both extremities in the THA group. We computed two logistic regressions using bilateral and ipsilateral imbalance as the predictors of THA surgery. We found that bilateral extensor imbalance may be used as a predictor for THA (Nagelkerke R² = 0.22). A decrease of the bilateral extensors imbalance by 8% decreases the probability of THA by 8%. The most interesting finding is that the evaluation of the bilateral extensor imbalance may be used as another clinical predictor for THA.

Exercise in patients with hip osteoarthritis - effects on muscle and functional performance: A randomized trial

Background: It is believed that clinical management of osteoarthritis should address muscle weakness to improve physical function and prevent disability and frailty.Objectives: This sub-study investigated the effects of supervised progressive resistance training (RT), supervised Nordic Walking (NW), and unsupervised home-based exercise (HBE) on muscle and functional performance; and associations between these exercise-induced changes in persons with hip osteoarthritis.Methods: Forty-two patients with hip osteoarthritis were recruited from a larger RCT (NCT01387867). All the groups (RT, n = 15; NW, n = 12; HBE, n = 15) exercised 1 h 3 times/week for 4 months. Quadriceps cross-sectional area (QCSA, MRI-determined); quadriceps strength (QMVC); leg extensor power (LEP); functional performance (chair stands (30sCS); stair climbs (TSC); and 6-minute walk (6MWT)) were assessed at baseline and 4 months.Results: Per protocol analyses (one-way ANOVA and Bonferroni test) showed significant between-group differences for improvements in QCSA in the most symptomatic leg favoring RT versus NW (2.3 cm², 95% CI [0.6, 3.9]) and HBE (2.3 cm² [0.8, 3.9]); and 30sCS (1.8 repetitions [0.2-3.3]), and 6MWT (35.1 m [3.5-66.7]) favoring NW versus HBE. Associations existed between exercise-induced changes in QCSA and QMVC (r = 0.366, p = .019) for the most symptomatic leg and between changes in 6MWT and QMVC (r = 0.320, p = .04) and LEP (r = 0.381, p = .01), respectively, for the least symptomatic leg.Conclusions: Resistance training appeared effective for improving muscle mass, but less effective for improving muscle strength, power, and functional performance. Only exercise-induced changes in muscle strength and power of the least symptomatic leg, not the most symptomatic leg, were related to changes in functional performance.

Individuals with Unilateral Mild-to-Moderate Hip Osteoarthritis Exhibit Lower Limb Kinematic Asymmetry during Walking But Not Sit-to-Stand

Asymmetry during gait is associated with the evolution of secondary osteoarthritis. Kinematic asymmetry has been reported in advanced stages of hip osteoarthritis but has not been evaluated in earlier stages of the disease or has it been directly compared with unilateral and bilateral hip osteoarthritis. Our objective was to evaluate within-group symmetry and compare between-group asymmetry for three-dimensional pelvis, hip, knee, and ankle kinematics during walking and sit-to-stand in individuals with unilateral mild-to-moderate hip OA, bilateral mild-to-moderate hip osteoarthritis, and healthy controls. Twelve individuals with unilateral mild-to-moderate hip OA, nine individuals with bilateral mild-to-moderate symptomatic and radiographic hip OA, and 21 age-comparable healthy controls underwent three-dimensional motion analysis during walking and sit-to-stand. Pelvis and lower limb joint angles were calculated using inverse kinematics and between-limb symmetry was assessed for each group. Any resulting asymmetries (most affected minus contralateral limb) were compared between groups. Participants with unilateral hip osteoarthritis exhibited significantly less hip extension (7.90°), knee flexion (4.72°), and anterior pelvic tilt (3.38°) on their affected limb compared with the contralateral limb during the stance phase of walking. Those with unilateral hip osteoarthritis were significantly more asymmetrical than controls for sagittal plane hip and pelvis angles. No significant asymmetries were detected within- or between-groups for sit-to-stand. Individuals with unilateral hip osteoarthritis exhibited lower limb asymmetries consistent with those reported in advanced stages of disease during walking, but not sit-to-stand. Consideration of the possible negative effects of gait asymmetry on the health of the affected and other compensating joints appears warranted in the management of hip OA.

Walking energetics and abductor strength are associated with physical activity in older women with hip osteoarthritis

BACKGROUND

Osteoarthritis (OA) can hinder physical activity in older adults for reasons that are not fully understood. Functional barriers may exist such as reduced muscle strength around the affected joint, potentially affecting physical activity. Aging-associated declines in energy capacity may also be exacerbated by OA. These factors may work together to influence physical activity in people with OA.

RESEARCH QUESTION

Our objective was to evaluate the combined role of walking energetics and hip abductor strength on physical activity in older women with hip OA.

METHODS

We evaluated 30 women with moderately symptomatic hip OA (61 ± 10 yrs; 30.7 ± 4.9 kg/m²) in this cross-sectional observational study. We measured physical activity using the UCLA activity score and quantified activity frequency and intensity using accelerometers worn for seven days (7 ± 2 days). We used a portable oxygen exchange system to measure energy used during walking at preferred speeds (relative to total energy capacity assessed using a six-minute walk test) and a dynamometer to measure hip abductor strength. We used Pearson correlations and regression analysis to test our hypotheses.

RESULTS

Greater energy used during walking was associated with lower self-reported physical activity (R=-0.626, p < 0.001), more sedentary time (R = 0.567, p = 0.002), and less light activity time (R=-0.644, p < 0.001). Lower hip abductor strength was associated with lower self-reported physical activity (R = 0.406, p = 0.039). While there was no association between hip abductor strength and energy used during walking, together these variables predicted 55.5 % of the variance in self-reported physical activity.

SIGNIFICANCE

Results suggest intervention targets to promote physical activity in this population.

Development of a Predictive Algorithm for Symptomatic Hip Abductor Tears in Patients Undergoing Primary Hip Arthroscopy

BACKGROUND

Patients presenting with lateral hip pain may pose a difficult diagnostic challenge, as pain can be due to various causes.

PURPOSE/HYPOTHESIS

The purpose was to identify risk factors and predictors for symptomatic hip abductor tears in a cohort of patients undergoing primary hip arthroscopy for femoroacetabular impingement syndrome. We hypothesized that body mass index (BMI), female sex, age, and presence of chondral damage would be significant predictors of hip abductor pathologies.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

Data were prospectively collected and retrospectively reviewed. Patients were included if they underwent primary hip arthroscopy between March 2009 and December 2019. Patients with Tönnis grade >1, previous hip conditions, incomplete radiographic data, or open procedures were excluded. All demographic variables, intraoperative measurements, and radiographic measurements were assessed using a bivariate analysis. A stepwise logistic regression was used to determine predictive variables.

RESULTS

In total, 255 hips with a hip abductor tear that underwent hip arthroscopy and 2106 hips without a tear that underwent hip arthroscopy were included. The stepwise logistic regression successfully created a predictive model using age, sex, BMI, lateral joint space, and alpha angle as variables. The efficiency of the predictive model was 90.7%, with an area under the curve of 0.894. The odds of having a hip abductor tear were 7.41 times higher in females (odds ratio [OR], 7.41; 95% CI, 4.61-11.9). Each additional year of age was associated with a 13.7% (OR, 1.137; 95% CI, 1.12-1.16) increase in the odds of having a tear. Similarly, with each 1-unit increase in BMI, the odds of having a tear increased by 3.4% (OR, 1.034; 95% CI, 1.01-1.06).

CONCLUSION

This study successfully created a predictive model that identified female sex (OR, 7.41), increasing age (OR, 1.137 for each year), and increased BMI (OR, 1.034 for each unit of BMI) as significant independent predictors of the presence of hip abductor tears in patients undergoing hip arthroscopy for femoroacetabular impingement syndrome. This model can be used in support of physical examination and imaging suggestive of hip abductor pathology to preoperatively identify the probability of a symptomatic hip abductor tear in these patients.

Lab-based feasibility and acceptability of neuromuscular electrical stimulation in hip osteoarthritis rehabilitation

INTRODUCTION

Neuromuscular electrical stimulation (NMES) could provide an alternative or adjunct treatment modality to induce muscle hypertrophy in the hip osteoarthritis population. This preliminary study evaluates the feasibility and acceptability of NMES to evoke involuntary muscle contractions in adults with advanced hip osteoarthritis.

METHODS

Thirteen adults with moderate-to-severe hip osteoarthritis and fifteen healthy, older adults were invited to a lab-based testing session. NMES was applied unilaterally to the knee extensors and hip abductors for one continuous, five-minute testing session. Data were collected on device acceptability, tolerability and muscle contractile force, and compared between groups.

RESULTS

Electrical stimulation of the knee extensors elicited a visible muscular contraction in 11 participants (85%) with hip osteoarthritis and 15 controls (100%) at an intensity acceptable to the participant. Electrical stimulation of the hip abductors elicited a muscular contraction in eight participants (62%) with osteoarthritis, and ten controls (67%). Muscle contractile force, pain, discomfort and acceptability did not differ between groups, however NMES of the knee extensors was favoured across all measures of assessment when compared to the hip abductors.

CONCLUSIONS

Electrical stimulation of the knee extensors may be a feasible and acceptable treatment modality to address muscle atrophy in adults with advanced hip osteoarthritis.

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.

STRENGTH AND FATIGUE MEASUREMENTS OF THE HIP FLEXOR AND HIP EXTENSOR MUSCLES: TEST-RETEST RELIABILITY AND LIMB DOMINANCE EFFECT

Background

Standardized testing of hip muscle strength and fatigue in the sagittal plane is important for assessing, treating and preventing a number of trunk and lower extremity pathologies. Furthermore, individuals displaying asymmetries of muscle strength between limbs are more likely to sustain an injury.

Purpose

To evaluate the test-retest reliability of isometric strength and isokinetic fatigue measurements of the hip flexor and hip extensor muscles, and to examine whether there is a significant limb dominance effect on strength, fatigue and flexor-extensor ratios.

Study design

Cross-sectional study.

Methods

To evaluate reliability, 30 healthy individuals (33.2 + /- 13.1 years) were included. On a separate occasion, 24 healthy individuals (29.0 + /- 10.3 years) participated to assess between-limb differences. Reliability was established using intraclass correlation coefficients (ICCs), standard error of measurements (SEM) and minimal detectable change (MDC). Isometric strength (best peak torque of three maximal contractions; Nm/kg), isokinetic fatigue (total work of 20 consecutive maximal concentric flexor-extensor contractions at 120 °/s; Joule/kg), and flexor-extensor ratios, were recorded using a Biodex dynamometer.

Results

Reliability was good-to-excellent (ICCs>0.83) and measurement errors were acceptable (SEM<13.6% and MDC%<37.8%). No significant between-limb differences in strength, fatigue and flexor-extensor ratios were detected.

Conclusions

Isometric strength and isokinetic fatigue of the hip flexor and hip extensor muscles can be reliably assessed in healthy individuals using the Biodex dynamometer. Limb dominance did not significantly affect strength, fatigue or flexor-extensor ratios.

Level of Evidence

2b.