Hip Muscle Weakness Research Articles

Anterior-approach total hip arthroplasty in patients with poliomyelitis: Long-term outcomes

ObjectiveIn patients with residual poliomyelitis-related impairments, total hip arthroplasty (THA) is challenging due to the high frequency of risk factors such as hip dysplasia, dislocation, muscle weakness, and fracture. The objective of this study was to assess the long-term functional and radiographic outcomes of anterior-approach THA with a ceramic-ceramic, dual-mobility, or constrained implant in patients with poliomyelitis sequelae. HypothesisTHA via the anterior approach with a ceramic-ceramic, dual-mobility, or constrained implant is a reliable technique that is not associated with excess risks of instability or aseptic loosening. Material and methodsThis single-centre retrospective study included consecutive patients with poliomyelitis sequelae who underwent THA between January 1998 and September 2019 via the anterior approach, with implantation of a ceramic-ceramic, dual-mobility, or constrained implant. The Harris Hip Score (HHS), implant position, and complications (e.g., infection and loosening) were collected during the most recent in-person visit. ResultsThe study included 19 patients (23 hips). Mean follow-up was 5.2 ± 4.2 years (range, 2.0–10.6 years). Only six of the 23 procedures were done on the side with greater muscle weakness. The mean HHS at last follow-up was 80.4 ± 10.4. A single procedure (1/23, 4%) was followed by a complication, consisting in intra-prosthetic dislocation 2 years after implantation of a dual-mobility cup. At last follow-up, the HHS was not associated with psoas and gluteus muscle strength (rs = 0.35, p = 0.11 and rs = 0.37, p = 0.09, respectively) and was not significantly different between the weaker vs. stronger side (82.7 ± 8.0 vs. 79.5 ± 11.3, respectively; p = 0.53). Cup position was more horizontal, thereby optimising function, when the procedure was done on the weaker vs. the stronger side (39.9° ± 4.3 vs. 45.0° ± 6.8, respectively; p = 0.02). ConclusionTHA is a good option for improving function in patients with poliomyelitis sequelae. THA via the anterior approach with a ceramic-ceramic, dual-mobility, or constrained implant is a reliable method that is not associated with an excess risk of instability or loosening. Level of evidenceIV.

Effects of static exercises on hip muscle fatigue and knee wobble assessed by surface electromyography and inertial measurement unit data

Hip muscle weakness can be a precursor to or a result of lower limb injuries. Assessment of hip muscle strength and muscle motor fatigue in the clinic is important for diagnosing and treating hip-related impairments. Muscle motor fatigue can be assessed with surface electromyography (sEMG), however sEMG requires specialized equipment and training. Inertial measurement units (IMUs) are wearable devices used to measure human motion, yet it remains unclear if they can be used as a low-cost alternative method to measure hip muscle fatigue. The goals of this work were to (1) identify which of five pre-selected exercises most consistently and effectively elicited muscle fatigue in the gluteus maximus, gluteus medius, and rectus femoris muscles and (2) determine the relationship between muscle fatigue using sEMG sensors and knee wobble using an IMU device. This work suggests that a wall sit and single leg knee raise activity fatigue the gluteus medius, gluteus maximus, and rectus femoris muscles most reliably (p < 0.05) and that the gluteus medius and gluteus maximus muscles were fatigued to a greater extent than the rectus femoris (p = 0.031 and p = 0.0023, respectively). Additionally, while acceleration data from a single IMU placed on the knee suggested that more knee wobble may be an indicator of muscle fatigue, this single IMU is not capable of reliably assessing fatigue level. These results suggest the wall sit activity could be used as simple, static exercise to elicit hip muscle fatigue in the clinic, and that assessment of knee wobble in addition to other IMU measures could potentially be used to infer muscle fatigue under controlled conditions. Future work examining the relationship between IMU data, muscle fatigue, and multi-limb dynamics should be explored to develop an accessible, low-cost, fast and standardized method to measure fatiguability of the hip muscles in the clinic.

Position- and Sex-Related Differences in Sagittal and Frontal Plane Concentric Isokinetic Hip Muscle Peak Torques and Agonist-Antagonist Ratios.

Hip muscle weakness is associated with many musculoskeletal conditions and athletic injuries. Isokinetic testing is often performed to measure a patient's strength or to assess treatment response. Patient sex and positioning during isokinetic strength testing may influence peak torque production and the agonist-antagonist peak torque ratios. However, different test positions are used clinically and in research to measure hip muscle strength. It is unknown how patient test position or sex impacts test results. The purpose of this study was to determine whether concentric isokinetic peak torques of sagittal and frontal plane hip muscles differ when tested in recumbent versus standing positions and if results were impacted by patient sex. Cross-sectional observational. Forty healthy adults (20 male, 20 female) participated. Concentric isokinetic hip torques of the hip flexors, extensors, abductors, and adductors were measured with participants in two positions (recumbent versus standing; 60°/second angular velocity). Peak torque values were normalized by body mass and height. Data were analyzed with mixed-model ANOVAs (sex x position). Effect sizes were examined using partial eta squared. No significant interactions or main effects for sex were found. Significant main effects for position were found for hip extensor and abductor peak torques and for hip flexor-extensor ratio. Hip extensor peak torque was greater when tested supine versus standing with a large effect size (p=.02, effect size =.14). Hip abductor peak torque was greater when tested sidelying versus standing with a medium effect size (p=.03, effect size =.12). Hip flexor-extensor agonist-antagonist ratio was greater when tested standing versus supine with a large effect size (p<.001, effect size =.27). Hip extensor and abductor concentric isokinetic peak torques were greater when tested in recumbent versus standing positions. In contrast, hip flexor-extensor ratio was greater when tested in standing versus supine. 3.

Concentric and eccentric hip musculotendon work depends on backpack loads and walking slopes

Hip muscle weakness is associated with low back and leg injuries. In addition, hiking with heavy loads is linked to high incidence of overuse injuries. Walking with heavy loads on slopes alters hip biomechanics compared to unloaded walking, but individual muscle mechanical work in these challenging conditions is unknown. Using movement simulations, we quantified hip muscle concentric and eccentric work during walking on 0° and ±10° slopes with, and without 40% bodyweight added loads, and with and without a hip belt. For gluteus maximus, psoas, iliacus, gluteus medius, and biceps femoris long head, both concentric and eccentric work were greatest during uphill walking. For rectus femoris and semimembranosus, concentric work was greatest during uphill and eccentric work was greatest during downhill walking. Loaded walking had greater concentric and eccentric work from rectus femoris, biceps femoris long head, and gluteus maximus. Psoas concentric work was greatest while carrying loads regardless of hip belt usage, but eccentric work was only greater than unloaded walking when using a hip belt. Loaded and uphill walking had high concentric work from gluteus maximus, and high eccentric work from gluteus medius and biceps femoris long head. Carrying heavy loads uphill may lead to excessive hip muscle fatigue and heightened injury risk. Effects of the greater eccentric work from hip flexors when wearing a hip belt on lumbar spine forces and pelvic stability should be investigated. Military and other occupational groups who carry heavy backpacks with hip belts should maintain eccentric strength of hip flexors and hamstrings.

Hip-focused physical therapy versus spine-focused physical therapy for older adults with chronic low back pain at risk for mobility decline (MASH): a multicentre, single-masked, randomised controlled trial

Previously, we identified a population of older adults with chronic low back pain, hip pain, and hip muscle weakness who had worse 12-month low back pain and functional outcomes than age-matched adults with only low back pain, indicating an increased risk for future mobility decline. We sought to determine whether tailored, hip-focused physical therapy reduced pain and functional limitations in this high-risk population compared with non-tailored, spine-focused physical therapy. We did a multicentre, single-masked, randomised controlled trial at three research-based sites in the USA. We recruited older adults (aged 60-85 years) with hip pain and weakness who reported moderate low back pain intensity at least half the days in the last 6 months. Patients were randomly assigned to hip-focused physical therapy or spine-focused physical therapy using permuted blocks with random block size, stratified by site and sex (ie, male or female). The primary outcomes were self-reported disability using the Quebec Back Pain Disability Scale (QBPDS) and performance-based 10-Meter Walk Test (10MWT) at 8 weeks. All analyses were done in the intention-to-treat population. Adverse events were collected by study staff via a possible adverse event reporting form and then adjudicated by site investigators. This trial was registered with ClinicalTrials.gov, NCT04009837. Between Nov 1, 2019, and April 30, 2022, 184 participants were randomly assigned to receive hip-focused (n=91) or spine-focused physical therapy (n=93) interventions. The mean age was 70·7 (SD 6·2) years. 121 (66%) of 184 participants were women, 63 (34%) were men, and 149 (81%) were White. At 8 weeks, the mean between-group difference on the QBPDS was 4·0 (95% CI 0·5 to 7·5), favouring hip-focused physical therapy. Both groups had similar, clinically meaningful gait speed improvements (10MWT) at 8 weeks (mean difference 0·004 m/s [95% CI -0·044 to 0·052]). No serious adverse events were related to study participation. Tailored hip-focused physical therapy demonstrated greater improvements in low back pain-related disability at 8 weeks. However, both hip-focused physical therapy and spine-focused physical therapy produced clinically meaningful improvements in disability and function for this high-risk population at 6 months. These findings warrant further investigation before clinical implementation. US National Institute on Aging of the National Institutes of Health.

Is there hip muscle weakness in adults with chronic non-specific low back pain? A cross-sectional study

BackgroundPatients with chronic low back pain may present changes in hip muscles. However, there is still limited and controversial evidence of the association between hip muscle weakness and chronic low back pain and whether this weakness can be assessed with functional tests. The purpose of this study was to assess whether there is hip muscle weakness in patients with non-specific chronic low back pain and whether there is an association between the positive Trendelenburg and Step-Down tests and hip muscle strength.MethodsThis cross-sectional study included 40 patients with chronic low back pain and 40 healthy participants, assessed in an outpatient clinic in Vitória, Espírito Santo, Brazil. Muscle strength was measured for the hip abductors, adductors, extensors, internal rotators, and external rotators using isometric manual dynamometry and functional stability was measured by the Trendelenburg and Step-Down tests. Muscle strength was compared using the t test for independent samples and the chi-square test. The association between the tests and strength was performed using a binary logistic regression analysis.ResultsHealthy participants showed a statistically significant greater muscle strength for the right hip abductors (mean difference [MD]: 28.1%, 95% confidence interval [CI]: 9.4 to 46.9), right adductors (MD: 18.7%, 95% CI: 6.2 to 31.2), right internal rotators (MD: 8.7%, 95% CI: 1.5 to 15.8), right extensors (MD: 21.1%, 95% CI: 6.2 to 31.2), left abductors (MD: 30.4%, 95% CI: 11.9 to 49), left adductors (MD: 18.4%, 95% CI: 3.7 to 33.2), and left extensors (MD: 21.6%, 95% CI: 6.6 to 36.5). There was no difference between groups for the positive functional tests, and there was no association between the tests and hip muscle strength.ConclusionPatients with chronic low back pain tend to have hip abductors, adductors, and extensors weakness. Furthermore, the functional tests should not be associated to hip muscle strength in patients with chronic low back pain.

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

BackgroundPeople 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 questionDo muscle contributions to the acceleration of the COM during walking differ between individuals with mild-to-moderate hip OA and controls? MethodsEleven 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. ResultsThere 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. SignificanceSubtle 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.

Knee pain – thinking beyond degeneration: a systematic review

Abstract Knee pain is the most common and challenging pain, that affects the performance and activities of daily living. Apart from the bones, the surrounding neuromuscular structures too are an integral part of the knee joint. The development of knee pain due to these surrounding neuromuscular structures, i.e. hip joint and ankle-foot complex is studied in this literature review. This systematic review was done for the purpose to summarise the literature mainly related to various neuromuscular factors related to neuro-muscle imbalances that affect knee pain other than degeneration. Observational studies related to knee pain published up to 2020 were reviewed in this paper. Strength of hip muscles and foot alignment were included in the study. We searched electronic database online for articles on ‘muscular imbalance that causes knee pain’ from Google scholar &amp; PubMed the quality of the selected researches was measured by using PEDro scale. Of the total, 14 selected studies demonstrated that individuals with knee pain had decreased muscular strength for hip abduction, external rotation and extension on the affected side compared with healthy individuals. Flat foot, abnormal Q angle and over pronation or supination of foot can also results in knee pain. This review concluded that hip muscle weakness and abnormal subtalar mal-alignment place extra stress on knee and create muscular imbalance leading to knee pain. This should be prevented by either proper posture or strengthening programs.

After scaling to body size hip strength of the residual limb exceeds that of the intact limb among unilateral lower limb prosthesis users

BackgroundHip muscles play a prominent role in compensating for the loss of ankle and/or knee muscle function after lower limb amputation. Despite contributions to walking and balance, there is no consensus regarding hip strength deficits in lower limb prosthesis (LLP) users. Identifying patterns of hip muscle weakness in LLP users may increase the specificity of physical therapy interventions (i.e., which muscle group(s) to target), and expedite the search for modifiable factors associated with deficits in hip muscle function among LLP users. The purpose of this study was to test whether hip strength, estimated by maximum voluntary isometric peak torque, differed between the residual and intact limbs of LLP users, and age- and gender-matched controls.MethodsTwenty-eight LLP users (14 transtibial, 14 transfemoral, 7 dysvascular, 13.5 years since amputation), and 28 age- and gender-matched controls participated in a cross-sectional study. Maximum voluntary isometric hip extension, flexion, abduction, and adduction torque were measured with a motorized dynamometer. Participants completed 15 five-second trials with 10-s rest between trials. Peak isometric hip torque was normalized to body mass × thigh length. A 2-way mixed-ANOVA with a between-subject factor of leg (intact, residual, control) and a within-subject factor of muscle group (extensors, flexors, abductors, adductors) tested for differences in strength among combinations of leg and muscle group (α = 0.05). Multiple comparisons were adjusted using Tukey’s Honest-Difference.ResultsA significant 2-way interaction between leg and muscle group indicated normalized peak torque differed among combinations of muscle group and leg (p < 0.001). A significant simple main effect of leg (p = 0.001) indicated peak torque differed between two or more legs per muscle group. Post-hoc comparisons revealed hip extensor, flexor, and abductor peak torque was not significantly different between the residual and control legs (p ≥ 0.067) but torques in both legs were significantly greater than in the intact leg (p < 0.001). Peak hip abductor torque was significantly greater in the control and residual legs than the intact leg (p < 0.001), and significantly greater in the residual than control leg (p < 0.001).ConclusionsOur results suggest that it is the intact, rather than the residual limb, that is weaker. These findings may be due to methodological choices (e.g., normalization), or biomechanical demands placed on residual limb hip muscles. Further research is warranted to both confirm, expand upon, and elucidate possible mechanisms for the present findings; and clarify contributions of intact and residual limb hip muscles to walking and balance in LLP users.Clinical Trial RegistrationN/A.

Loss of calpain3b in Zebrafish, a Model of Limb-Girdle Muscular Dystrophy, Increases Susceptibility to Muscle Defects Due to Elevated Muscle Activity.

Limb-Girdle Muscular Dystrophy Type R1 (LGMDR1; formerly LGMD2A), characterized by progressive hip and shoulder muscle weakness, is caused by mutations in CAPN3. In zebrafish, capn3b mediates Def-dependent degradation of p53 in the liver and intestines. We show that capn3b is expressed in the muscle. To model LGMDR1 in zebrafish, we generated three deletion mutants in capn3b and a positive-control dmd mutant (Duchenne muscular dystrophy). Two partial deletion mutants showed transcript-level reduction, whereas the RNA-less mutant lacked capn3b mRNA. All capn3b homozygous mutants were developmentally-normal adult-viable animals. Mutants in dmd were homozygous-lethal. Bathing wild-type and capn3b mutants in 0.8% methylcellulose (MC) for 3 days beginning 2 days post-fertilization resulted in significantly pronounced (20-30%) birefringence-detectable muscle abnormalities in capn3b mutant embryos. Evans Blue staining for sarcolemma integrity loss was strongly positive in dmd homozygotes, negative in wild-type embryos, and negative in MC-treated capn3b mutants, suggesting membrane instability is not a primary muscle pathology determinant. Increased birefringence-detected muscle abnormalities in capn3b mutants compared to wild-type animals were observed following induced hypertonia by exposure to cholinesterase inhibitor, azinphos-methyl, reinforcing the MC results. These mutant fish represent a novel tractable model for studying the mechanisms underlying muscle repair and remodeling, and as a preclinical tool for whole-animal therapeutics and behavioral screening in LGMDR1.

Strength Training Rehabilitation Incorporating Power Exercises (STRIPE) for individuals with patellofemoral pain: a randomised controlled trial protocol

Patellofemoral pain (PFP) is a chronic condition that presents with patellar pain during various daily and recreational activities. Individuals with PFP have a wide range of impairments that result in...

The effect of a telehealth exercise intervention on balance in adults with Down syndrome.

People with Down syndrome often present with balance deficits, which compromise safety during daily activity. While evidence shows that exercise can improve balance in the Down syndrome population, it is unclear if a telehealth method will elicit similar benefits. We aimed to examine the effects of a virtual exercise program on balance in adults with Down syndrome. Eighteen low-active participants with Down syndrome completed a 12-week telehealth exercise program based on the Mann Method. Balance testing took place before and after the intervention, which included: TUG, MCTSIB, FICSIT-4, and FRT. This study was registered as a clinical trial on ClinicalTrials.gov, identifier: NCT04647851. Significant improvement was seen in the TUG (p=.043), FICSIT-4 (p=.019) and FRT (p=.019). All participants achieved maximum scores on the MCTSIB in pre- and post-testing. Balance in low-active adults with Down syndrome significantly improved following the telehealth exercise program, which we attribute to the tailored exercises that address visual/vestibular deficits and hip muscle weakness.

Hip Adductor, Abductor Muscles Strength, and Performance in Participants with and without Low Back Pain

Introduction: Weakness of hip muscles is common in individuals with chronic non- specific low back pain (CNSLBP). Also, hip joint performance can be influenced by the weakness of hip muscles. This study aimed to compare the strength and performance of hip adductor and abductor muscles between subjects with and without CNSLBP and to investigate their association with disability level.&#x0D; Materials and Methods: This case-control study included 41 participants with CNSLBP and 41 healthy participants. The strength of hip abductor and adductor muscles were measured using a dynamometer and their performance was assessed using the one-leg hop test. The disability level in the CNSLBP group was assessed using the oswestry disability index (ODI). Data were analyzed using an independent sample t test and Pearson correlation coefficient.&#x0D; Results: No significant differences were observed between groups for hip muscle strength. One-leg hop test scores of the left lower extremity in the lateral direction were significantly higher in the CNSLBP group compared to the control group. Also, no significant relationships were observed between the total score of ODI and hip muscle strength or performance in the CNSLBP group.&#x0D; Conclusion: It’s recommended that evaluation and exercise therapy of participants with CNSLBP be performed during functional performance tasks.

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.

Gluteal Central Activation in Females With Patellofemoral Pain: A Preliminary Study

Lesser hip muscle strength is commonly observed in females with patellofemoral pain (PFP) compared with females without PFP and is associated with poor subjective function and single-leg squat (SLS) biomechanics. Hip muscle weakness is theorized to be related to PFP, suggesting centrally mediated muscle inhibition may influence the observed weakness. The central activation ratio (CAR) is a common metric used to quantify muscle inhibition via burst superimposition. However, gluteal inhibition has yet to be evaluated using this approach in females with PFP. The study objectives are to (1)describe gluteal activation in the context of subjective function, hip strength, and squatting biomechanics and (2)examine the relationship of gluteal activation with subjective function and squatting biomechanics in females with PFP. Cross-sectional. Seven females with PFP (age = 22.8 [3.6]y; mass = 69.4 [18.0]kg; height = 1.67 [0.05]m, duration of pain = 6-96mo) completed this study. Subjective function was assessed with the Anterior Knee Pain Scale, while fear-avoidance beliefs were assessed with the Fear-Avoidance Belief Questionnaire physical activity and work subscales. Biomechanical function was assessed with peak hip and knee angles and moments in the sagittal and frontal planes during SLS. Gluteus medius (GMed) and gluteus maximus (GMax) activation were assessed with the CAR. Descriptive statistics were calculated, and relationships between variables were assessed with Spearman rho correlations. The CAR of GMed and GMax was 90.5% (8.1%) and 84.0% (6.3%), respectively. Lesser GMed CAR was strongly associated with greater hip adduction during SLS (ρ = -.775, P = .02) and greater fear-avoidance beliefs-physical activity subscale (ρ = -.764, P = .018). We found a wide range in GMed and GMax activation across females with PFP. Lesser GMed activation was associated with greater hip adduction during SLS and fear of physical activity, suggesting that gluteal inhibition should be assessed in patients with PFP.

Are muscle knots causing my hip tightness and weakness?

In this presentation, I will present the role of trigger points (TrPs) in chronic non-specific low back pain (CNSLBP). Travell and Simons define a TrP as “a hyperirritable spot in skeletal muscle that is associated with a hypersensitive palpable nodule in a taut band” (Simons et al., 1999, p. 5). Active and latent TrPs are proposed to cause restricted range of movement (ROM) and muscle weakness. Simons and Travell pioneered TrP research with their publications of “The Trigger Point Manuals” (1983 &amp; 1992); subsequently research into TrPs has informed knowledge of musculoskeletal disorders. The prevalence of TrPs in people with CNSLBP is high; especially in the gluteus medius (GMed) muscles. CNSLBP is a complex and costly condition; with which treatment is not always successful. In this population, decreased hip ROM and hip muscle weakness are common findings. This study investigated if the presence of active TrPs was associated with these deficits in the hips, when compared with participants with latent TrPs and zero TrPs. Forty-two participants with CNSLBP underwent hip passive ROM and hip muscle strength testing; with palpation of their GMed muscles to identify the presence and type of TrPs. Analysis showed varying results regarding hip ROM and TrP status. There was an association between hip strength and TrP status. Participants with zero TrPs were the strongest and those with TrPs were weaker. In general, those with latent TrPs were the weakest. This study adds knowledge to the role that TrPs play in muscle strength and the characteristics of TrPs. This is significant for the treatment of CNSLBP and the development of more effective treatment of this multi-factorial condition.

Hip Microinstability: Understanding a Newly Defined Hip Pathology in Young Athletes

Microinstability is an increasingly recognized diagnosis in young athletes presenting with hip pain. Causes of microinstability may include abnormality of the hip bony anatomy, acetabular labral tears, joint capsule laxity or injury, and muscle dysfunction. Borderline hip dysplasia is an increasingly recognized factor predisposing to microinstability. The capsuloligamentous structures of the hip, particularly the iliofemoral ligament, provide important restraints to femoral head motion, and iatrogenic defects can predispose patients to instability after surgery. Injury to the acetabular labrum may disrupt its important hip-stabilizing properties including the suction seal and improved acetabular depth. Hip muscle weakness or imbalance may result in increased femoral head motion within the acetabulum. The diagnosis of hip microinstability can be challenging, and the history is often nonspecific. Physical examination maneuvers include the anterior apprehension, prone instability, axial distraction, and abduction-hyperextension-external rotation tests. Radiographic features may include borderline hip dysplasia, femoral head-neck junction cliff sign, and an elevated femoral-epiphyseal acetabular roof index. Magnetic resonance arthrography may demonstrate a capsular defect, capsular thinning, or labral pathology. Diagnostic intra-articular injection of anesthetic can confirm the intra-articular nature of the pathology. Management of hip microinstability focuses on strengthening the dynamic stabilizers of the hip through focused physical therapy. Surgery may be considered in recalcitrant cases where symptoms persist despite optimization of hip stabilizer strength. In such cases, addressing the primary source of instability through labral repair or reconstruction and capsular repair or plication can be considered. In highly selected cases, surgery can result in excellent outcomes.

Effects of Whole-Season Training and Match-Play on Hip Adductor and Abductor Muscle Strength in Soccer Players: A Pilot Study.

Previous investigations have associated weakness of hip muscles with a higher likelihood of developing hip groin injury. However, no previous investigation has examined the influence of soccer training and match-play during the season on maximal isometric hip adductor and abductor muscle strength. Maximal hip adductor and abductor muscle strength would increase after the preseason, maintaining relatively constant levels across the soccer season. Cross-sectional study. Level 3. A total of 26 semiprofessional male soccer players underwent measurements of maximal isometric hip adductor and abductor muscle strength at 3 time points of the soccer season: preseason, midseason, and end-season to investigate the longitudinal effect of soccer training and competition during a complete season on maximal isometric hip adductor and abductor muscle strength in the semiprofessional Spanish soccer player. Compared with preseason, hip abductor muscle strength increased in the midseason (14.2% and 17.1%, for dominant and nondominant limb, respectively; P < 0.001) and in the end-season (13.1%; P = 0.005, and 14.1%; P < 0.005). In contrast, hip adductor muscle strength remained unchanged across the season in both limbs. As a result, the adductor/abductor strength ratio in the nondominant limb was reduced at midseason and end-season time points (-14.6% and -18.4%, respectively; P < 0.001) with a corresponding tendency in the dominant limb (-9.3% and -15.0%, respectively; P > 0.05). While maximal hip abductor muscle strength increased throughout the season, hip adductor muscle strength remained stable across the season. This produced a substantial deficit in hip adductor/abductor strength ratio at midseason and end-season. The progressive imbalance in adductor/abductor strength across the soccer season may be an indicator of increased risk of groin injury and may reinforce the need for preventive rehabilitation activities focused on enhancing adductor muscle strength.

Confidence and Knowledge of Athletic Trainers in Managing Patellofemoral Pain.

Patellofemoral pain (PFP) is prevalent and challenging to manage. Most patients with PFP are unsatisfied with their knee function at 6 months after treatment and report ongoing pain up to 16 years after diagnosis. The confidence and knowledge of athletic trainers (ATs) in providing evidence-based care to people with PFP is unknown. To investigate the confidence and knowledge of ATs in the diagnosis, risk factors, prognosis, and treatment with current evidence for PFP. Cross-sectional study. Online survey. A random sample of 3000 ATs were invited to participate; 261 completed the survey (10% participation rate, 88% completion rate). We surveyed AT demographics, confidence in PFP management, and knowledge related to diagnosis, risk factors, prognosis, and treatment. The confidence and knowledge of ATs in managing PFP was assessed. Their beliefs about evidence were compared with the available evidence (ie, consensus statements, position statements, systematic reviews). Of the ATs surveyed, 91% were confident that their management of PFP aligned with the current evidence, but only 59% were confident in identifying risk factors for PFP development. In addition, 91% to 92% of ATs agreed that quadriceps and hip muscle weakness were risk factors for PFP, which aligns with the current evidence for the former but not the latter. Moreover, 93% to 97% of ATs' responses related to therapeutic exercise aligned with current evidence. However, 35% to 48% supported the use of passive treatments, such as electrophysical agents and ultrasound, which did not align with the current evidence. Most ATs were aware of supporting evidence for therapeutic exercise in PFP management and were confident providing it, creating a strong foundation for evidence-based care. However, varying levels of awareness of the evidence related to risk factors and passive treatments for PFP highlight the need for professional development initiatives to better align ATs' knowledge with the current evidence.

Influence of simulated hip muscle weakness on hip joint forces during deep squatting

ABSTRACT This study aimed to determine the effects of simulated hip muscle weakness on changes in hip joint forces during deep squat motion. Ten healthy individuals performed squat motion at three different positions (0° foot angle [N-squat], 10° toe-in [IN-squat], and 30° toe-out [OUT-squat]). A scaled musculoskeletal model for each participant was used to calculate the muscle and hip joint forces. For each hip muscle, models of full strength, mild muscle weakness (15% decrease), and severe muscle weakness (30% decrease) were created. The muscles affecting the hip joint forces were identified, and the rate of change in the joint forces was compared among the three squat conditions. The anterior hip joint force was increased in the muscle weakness models of the inferior gluteus maximus (iGlutMax) and iGlutMax+deep external rotator (ExtRot) muscles. With 30% muscle weakness of these muscles, statistically significant differences in the rate of increase in the anterior joint force were observed in the following order: IN-squat (iGlutMax, 29.5%; iGlutMax+ExtRot, 41.4%), N-squat (iGlutMax, 18.3%; iGlutMax+ExtRot, 27.8%), and OUT-squat (iGlutMax, 5.6%; iGlutMax+ExtRot, 9.3%). OUT-squat may be recommended to minimize the increase in hip joint forces if accompanied by hip muscle weakness.