SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Abduction

168

In total hip arthroplasty, determining the impingement free range of motion requirement is a complex task. This is because in the native hip, motion is restricted by both impingement as well as soft tissue restraint. The aim of this study is to determine a range of motion benchmark which can identify motions which are at risk from impingement and those which are constrained due to soft tissue. Two experimental methodologies were used to determine motions which were limited by impingement and those motions which were limited by both impingement and soft tissue restraint. By comparing these two experimental results, motions which were limited by impingement were able to be separated from those motions which were limited by soft tissue restraint. The results show motions in extension as well as flexion combined with adduction are limited by soft tissue restraint. Motions in flexion, flexion combined with abduction and adduction are at risk from osseous impingement. Consequently, these motions represent where the maximum likely damage will occur in femoroacetabular impingement or at most risk of prosthetic impingement in total hip arthroplasty.

Concepts: Hip replacement, Hip, Pelvis, Orthopedic surgery, Extension, Abduction, Adduction, Gracilis muscle

35

Hip adductor injuries are frequent in football, and players with low adductor strength appear to be at increased risk of injury. High adductor muscle activity has been shown in the Copenhagen Adduction exercise (CA); however, an associated strength gain has not been investigated. This study aims to examine the eccentric hip adduction strength (EHAD) gain using the CA in-season. Two U-19 sub-elite football teams, including 24 football players, were randomized to either an 8-week supervised progressive training program in addition to the usual training (intervention) or to continue training as usual (control). EHAD, eccentric hip abduction strength (EHAB), and side-bridge endurance were measured using reliable test procedures at baseline and follow-up by a blinded tester. There was a significant interaction between group and time on EHAD, EHAB, and EHAD/EHAB ratio (P < 0.025). The intervention group demonstrated a 35.7% increase in EHAD (P < 0.001); a 20.3% increase in EHAB (P = 0.003), and 12.3% increase in EHAD/EHAB ratio (P = 0.019). No significant within-group differences were found in the control group (P > 0.335). Compliance was 91.25%, and median muscle soreness ranged from 0 to 2. The CA implemented in-season with an 8-week progressive training program elicited a large significant increase in EHAD, EHAB, and EHAD/EHAB ratio.

Concepts: Randomized controlled trial, Hip, Abduction, Adduction, Gracilis muscle, Muscles of the hip, Adductor muscles of the hip

28

The relevance of Henry’s pelvic deltoid and its contribution to hip abductor strength is often not considered in hip arthroplasty. This small cadaveric study (n = 11) aimed to quantify the relative contributions of the pelvic deltoid muscles to abductor strength and to assess how different surgical approaches(anterolateral, direct lateral and posterior) impact on each of these muscle groups. We inspected the path of each approach and measured the cross-sectional area of the hip abductors, from which the contribution of each muscle to abductor moment was derived. We concluded that the posterior approach has the least impact on the pelvic deltoid and overall abductor moment.

Concepts: Muscle, Hip replacement, Hip, Pelvis, Orthopedic surgery, Joint replacement, Human anatomy, Abduction

27

: Children with obstetrical brachial plexus injury often develop an internal rotation and adduction contracture about the shoulder as a secondary deformity, resulting in an inability to externally rotate and abduct the shoulder. The Hoffer procedure is evaluated for its potential benefit in improving shoulder abduction and external rotation and its impact on activities of daily living.

Concepts: Shoulder, Deltoid muscle, Brachial plexus, Abduction, Adduction

3

Study Design Cross-sectional cohort study. Background Athletes with femoroacetabular impingement (FAI) syndrome have cam and/or pincer morphology, pain on orthopaedic testing, and often have reduced hip range of motion (ROM) and strength. However, cam and pincer morphology are also common in asymptomatic hips. Therefore, it is currently unknown whether the ROM and strength deficits observed in athletes with FAI syndrome result from the variance in their bony hip morphology or hip condition. Objectives To investigate the relationship between musculoskeletal screening findings and bony hip morphology in asymptomatic male soccer players. Methods Male professional soccer players in Qatar were screened specifically for hip/groin pain in 2 consecutive seasons. The screening battery included: pain provocation, ROM and strength tests, and hip radiographs. Univariate and multivariate regression analyses using generalised estimating equations evaluated the relationship between musculoskeletal screening findings and each bony hip morphological variant (cam, large cam, pincer, and acetabular dysplasia). Results Asymptomatic hips with cam and large cam morphology were associated with lower ROM in internal rotation and bent knee fall out, and a higher likelihood of pain on provocation testing. Pincer morphology was associated with lower abduction ROM and higher abduction strength. Acetabular dysplasia was associated with higher abduction ROM. Each association was weak and demonstrated poor or failed discriminatory power. Conclusion Bony hip morphology is associated with hip joint ROM and abduction strength, but musculoskeletal screening tests have a poor ability to discriminate between the different morphologies. J Orthop Sports Phys Ther, Epub 16 Mar 2018. doi:10.2519/jospt.2018.7848.

Concepts: Regression analysis, Cohort study, Hip replacement, Hip, Pelvis, Sartorius muscle, Abduction, Adduction

2

Load is used to increasingly challenge muscle function and has been shown to increase muscle activity levels with no change in activation patterns during shoulder flexion, extension, adduction and rotation. However, the effect of load during shoulder abduction, a movement commonly used in assessment of shoulder dysfunction and to improve shoulder function, has not been comprehensively examined. Therefore, the purpose of this study was to determine if load influences shoulder muscle activation patterns and levels during scapular plane abduction in normal subjects.

Concepts: Muscle, Hip, Group, Shoulder, Deltoid muscle, Abduction, Adduction

2

Study Design Controlled laboratory study, repeated-measures design. Objectives To compare hip abductor muscle activity and hip and knee joint kinematics in the moving limb to the stance limb during resisted side-stepping and also to determine if muscle activity was affected by the posture (upright standing versus squat) used to perform the exercise. Background Hip abductor weakness has been associated with a variety of lower extremity injuries. Resisted side-stepping is often used as an exercise to increase strength and endurance of the hip abductors. Exercise prescription would benefit from knowing the relative muscle activity level generated in each limb and for different postures during the side-stepping exercise. Methods Twenty-four healthy adults participated in this study. Kinematics and surface electromyographic (EMG) data from the gluteus maximus, gluteus medius, and tensor fascia lata (TFL) were collected as participants performed side-stepping with a resistive band around the ankle while maintaining each of 2 postures: 1) upright standing and 2) squat. Results Mean normalized EMG signal amplitude of the gluteus maximus, gluteus medius, and TFL was higher in the stance limb than the moving limb (P≤.001). Gluteal muscle activity was higher, while TFL muscle activity was lower, in the squat posture compared to the upright standing posture (P<.001). Hip abduction excursion was greater in the stance limb than in the moving limb (P<.001). Conclusions The 3 hip abductor muscles respond differently to the posture variations of side-stepping exercise in healthy individuals. When prescribing resisted side-stepping exercises, therapists should consider the differences in hip abductor activation across limbs and variations in trunk posture. J Orthop Sports Phys Ther, Epub 10 Jul 2015. doi:10.2519/jospt.2015.5888.

Concepts: Muscle, Exercise, Electromyography, Hip, Gluteal muscles, Abduction, Gluteus medius muscle, Squat

1

Study Design Secondary analysis, cross-sectional study. Background Chronic hip joint pain (CHJP) can lead to limitations in activity participation, but the musculoskeletal factors associated with the condition are relatively unknown. Understanding the factors associated with CHJP may help develop rehabilitation strategies to improve quality of life of individuals with long-term hip pain. Objectives To compare measures of hip abductor muscle volume and hip abductor muscle strength between women with CHJP and asymptomatic controls. Methods Thirty women, 15 with CHJP and 15 matched asymptomatic controls (18-40 years of age), participated in this study. Magnetic resonance imaging was used to determine the volume of the primary hip abductor muscles, consisting of gluteus medius (GMed), gluteus minimus (GMin), a small portion of gluteus maximus (GMax), and tensor fascia latae (TFL), within a defined region of interest. Break tests were performed using a handheld dynamometer to assess hip abductor strength. During the strength test, the participant was positioned in sidelying with the involved hip in 15° abduction. Independent-sample t tests were used to compare muscle volume and strength values between those with CHJP and asymptomatic controls. Results Compared to asymptomatic controls, women with CHJP demonstrated significantly increased gluteal muscle volume (228±40cm(3) versus 199±29cm(3); p=.032), but decreased hip abductor strength (74.6±16.8Nm versus 93.6±20.2Nm; p=.009). There were no significant differences in TFL muscle volume between the two groups (p=.640). Conclusions Women with CHJP appear to have larger gluteal muscles, but decreased hip abductor strength compared to asymptomatic controls. J Orthop Sports Phys Ther, Epub 9 Oct 2017. doi:10.2519/jospt.2017.7380.

Concepts: Hip, Gluteus maximus muscle, Gluteal muscles, Abduction, Adduction, Gluteus medius muscle, Squat, Gluteus minimus muscle

1

Weak hip abductors may be related with increased hip adduction and knee abduction angular movement, which may be risk factors of lower extremity injuries. Since the role of eccentric hip abduction strength (EHAS) on hip adduction angular movement and the knee abduction angular movement (KABD) remains unclear and the purpose of the present study was to explore the association between EHAS and hip- and knee angular movement. In 100 healthy male recreational runners, EHAS was quantified using an isokinetic dynamometer, while hip- and knee angular movement were collected using pressure sensitive treadmill and Codamotion active marker system. By using multiple linear regression models (n=186 legs), no relationships between EHAS and hip- and knee kinematics were found. A possible reason for the lack of relationship between EHAS and hip and knee kinematics may be owing to differences in the running kinematics. Some runners with weak EHAS may compensate the weakness by leaning towards the stance limb and thereby reduces the demand on the hip abductors with the consequence of increased knee abduction moment, which may lead to an increased knee abduction angular excursion. Possible, others mechanism as the quadriceps strength and activity in the hip and thigh muscles may also be able to explain the lack of relationship that may or may not exist. Despite the inconclusive results of the present study, the findings may suggest that weak hip abductor muscles may be a relevant factor to focus on in future studies. This article is protected by copyright. All rights reserved.

Concepts: Regression analysis, Linear regression, Hip, All rights reserved, Copyright, Abduction, Adduction, Muscles of the hip

1

Study Design Systematic review with meta-analysis. Background The optimum type of exercise interventions for people with knee osteoarthritis may be guided by a complete understanding of impairments associated with the condition. Our current understanding of hip strength deficits in this population is based on studies with conflicting findings and small samples. There is a need to systematically review and pool current evidence. Objectives To determine if hip strength deficits exist in people with symptomatic knee osteoarthritis. Methods Electronic databases (MEDLINE, CINAHL, EMBASE, COCHRANE, and Psycinfo) were searched through February 2016. Studies comparing hip strength in people diagnosed with symptomatic knee osteoarthritis to healthy control participants were included in the review. A meta-analysis with random effects was applied to relevant data from included studies and a modified GRADE approach was used to evaluate the quality of evidence for each pooled analysis. Results Five studies were included in the review. Meta-analysis revealed moderate quality evidence of weaker isometric and isokinetic hip abduction strength in people with knee osteoarthritis (moderate difference; 7% to 24% weaker); very low quality evidence of no difference in isometric hip adduction strength. There was very low to moderate quality evidence of weaker isokinetic hip strength in the remaining planes of motion (moderate to large differences; 14% to 54% weaker). Conclusion Significant hip strength deficits exist in people with knee osteoarthritis. Hip strength assessment should be considered in clinical practice and may assist with directing targeted management strategies. Level of Evidence Symptom prevalence, 1a. J Orthop Sports Phys Ther, Epub 3 Jul 2016. doi:10.2519/jospt.2016.6618.

Concepts: Evidence-based medicine, Systematic review, Strength training, Meta-analysis, Abduction, Adduction, Muscles of the hip, 2016