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Concept: Adduction

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

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

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STUDY DESIGN: Controlled laboratory study, repeated measures design. OBJECTIVES: To compare hip abductor muscle activity during selected exercises using fine-wire electromyography (EMG), and determine which exercises are best for activating gluteus medius and the superior portion of gluteus maximus while minimizing activity of tensor fascia lata (TFL). BACKGROUND: Abnormal hip kinematics (i.e. excessive hip adduction and internal rotation) has been linked to certain musculoskeletal disorders. The TFL is a hip abductor but also internally rotates the hip. As such, it may be important to select exercises that activate the gluteal hip abductors while minimizing activation of TFL. METHODS: Twenty healthy persons participated. EMG signals were obtained from the gluteus medius, superior gluteus maximus, and TFL muscles using fine-wire electrodes as subjects performed 11 different exercises. Normalized EMG signal amplitude was compared among muscles for each exercise using multiple 1-way repeated measures analyses of variance (ANOVAs). A descriptive gluteal-to-TFL muscle activation (GTA) index was used to identify preferred exercises for recruiting the gluteal muscles while minimizing TFL activity. RESULTS: Both gluteal muscles were significantly (P<.05) more active than TFL in unilateral and bilateral bridging, quadruped hip extension (knee flexed and extending), the clam, side-stepping, and squatting. The GTA index ranged from 18 to 115, and was highest for the clam (115), side-step (64), unilateral bridge (59), and both quadruped exercises (50). CONCLUSION: If the goal of rehabilitation is to preferentially activate the gluteal muscles while minimizing TFL activation, then the clam, side-step, unilateral bridge, and both quadruped hip extension exercises would appear to be most appropriate.J Orthop Sports Phys Ther, Epub 16 November 2012. doi:10.2519/jospt.2013.4116.

Concepts: Extension, Adduction, Hip, Muscle, Gluteus maximus muscle, Gluteal muscles, Gluteus medius muscle, Electromyography

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

10

The purpose of this study was to compare the relationship between several measures of single-joint, isometric, eccentric, and squat strength and unilateral and bilateral landing mechanics at the hip and knee in females. Twenty six healthy female subjects with previous athletic experience (height 165.1 ± 7.01 cm, mass 60.91 ± 7.14 kg, age 20.9 ± 1.62 yrs) participated in this study. Hip and knee mechanics were measured using the MotionMonitor capture system (Innovative Sports Training Inc, Chicago, IL.) with 3-dimensional electromagnetic sensors during bilateral (60 cm) and unilateral drop jumps (30 cm). On a separate day, isometric hip extension, external rotation, and abduction strength (lbs) were measured using a handheld dynamometer (Hoggan Health Industries, Inc., West Jordan, Utah). Eccentric and isometric knee strength were measured on the Biodex IV Isokinetic Dynamometer (Biodex Medical Systems, Inc., Shirley, NJ). Free weight was used to measure the bilateral squat and a modified single-leg squat. The strongest correlations were found between squat strength and knee valgus (-0.77 ≤ r ≤ -0.83) and hip adduction (-0.5 ≤ r ≤ -0.65). After controlling for squat strength, hip external rotation strength and unilateral knee valgus (-0.41), hip abduction strength and bilateral knee valgus (-0.43), and knee flexion strength and bilateral hip adduction (-0.57) remained significant. Eccentric knee flexion strength and unilateral knee internal rotation was the only significant correlation for eccentric strength (-0.40). Squat strength appears to be the best predictor of knee valgus and was consistently related to hip adduction. Isometric and eccentric measures demonstrated few significant correlations with hip and knee excursion while demonstrating a low to moderate relationship. Hip and knee flexion and rotation do not appear to be related to strength. Squat strength should receive consideration during risk assessment for non-contact knee injury.

Concepts: Semimembranosus muscle, Sartorius muscle, Flexion, Gracilis muscle, Knee, Extension, Hip, Adduction

5

The FIFA 11+ was developed as a complete warm-up program to prevent injuries in soccer players. Although reduced hip adduction strength is associated with groin injuries, none of the exercises included in the FIFA 11+ seem to specifically target hip adduction strength.

Concepts: Strength training, Stretching, Association football, Adduction, FIFA, FIFA World Cup, Exercise, Randomized controlled trial

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Tendinopathy of the gluteus medius and gluteus minimus tendons is now recognized as a primary local source of lateral hip pain. The condition mostly occurs in mid-life both in athletes and in subjects who do not regularly exercise. Females are afflicted more than males. This condition interferes with sleep (side lying) and common weight-bearing tasks, which makes it a debilitating musculoskeletal condition with a significant impact. Mechanical loading drives the biological processes within a tendon and determines its structural form and load-bearing capacity. The combination of excessive compression and high tensile loads within tendons are thought to be most damaging. The available evidence suggests that joint position (particularly excessive hip adduction), together with muscle and bone elements, are key factors in gluteal tendinopathy. These factors provide a basis for a clinical reasoning process in the assessment and management of a patient presenting with localized lateral hip pain from gluteal tendinopathy. Currently, there is a lack of consensus as to which clinical examination tests provide best diagnostic utility. On the basis of the few diagnostic utility studies and the current understanding of the pathomechanics of gluteal tendinopathy, we propose that a battery of clinical tests utilizing a combination of provocative compressive and tensile loads is currently best practice in its assessment. Management of this condition commonly involves corticosteroid injection, exercise or shock wave therapy, with surgery reserved for recalcitrant cases. There is a dearth of evidence for any treatments, so the approach we recommend involves managing the load on the tendons through exercise and education on the underlying pathomechanics.

Concepts: Tendinopathy, Gluteus minimus muscle, Management, Adduction, Muscle, Gluteal muscles, Tendon, Gluteus medius muscle

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

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PURPOSE: Patellofemoral pain (PFP) is the leading cause of knee pain in runners. Proximal and distal running mechanics have been linked to the development of PFP. However, the lack of prospective studies limits establishing a causal relationship of these mechanics to PFP. The purpose of this study was to prospectively compare running mechanics in a group of female runners who went on to develop PFP compared to healthy controls. It was hypothesized that runners who go on to develop PFP would exhibit greater hip adduction, hip internal rotation, and greater rear foot eversion. METHODS: 400 healthy female runners underwent an instrumented gait analysis and were then tracked for any injuries that they may have developed over a 2 year period. Fifteen cases of PFP developed which were confirmed by a medical professional. Their initial running mechanics were compared to an equal number of runners who remained uninjured. RESULTS: We found that female runners who developed PFP exhibited significantly greater hip adduction (p=0.007). No statistically significant differences were found for the hip internal rotation angle (p=0.47) or rearfoot eversion (p=0.1). CONCLUSIONS: The finding of greater hip adduction in female runners who develop PFP is in agreement with previous cross sectional studies. These results suggest that runners who develop PFP utilize a different proximal neuromuscular control strategy than those who remain healthy. Injury prevention and treatment strategies should consider addressing these altered hip mechanics.

Concepts: Locomotion, Human Development Index, Experiment, Epidemiology, Medicine, Adduction, Statistical significance, Causality

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Study Design Ancillary analysis, time-controlled randomized clinical trial. Background Movement pattern training (MPT) has been shown to improve function among patients with chronic hip joint pain (CHJP). Objective Determine the association among treatment outcomes and mechanical factors associated with CHJP. Methods Twenty-eight patients with CHJP, 18-40 years, participated in MPT, either immediately after assessment or after a wait-list period. MPT included task-specific training to reduce hip adduction motion during functional tasks and hip muscle strengthening. Hip-specific function was assessed using modified Harris Hip Score (MHHS) and Hip disability and Osteoarthritis Outcome Score (HOOS). 3D kinematic data were used to quantify hip adduction motion, dynamometry to quantify abductor strength, and magnetic resonance imaging to measure femoral head sphericity using alpha angle. Paired t-tests assessed change from pre- to post-treatment. Spearman correlations assessed associations. Results There was significant improvement in MHHS and HOOS (P<.02), adduction motion (P=.045) and abductor strength (P=.01) between pre- and post-treatment. Reduction in hip adduction motion (r=-0.67, P<.01) and lower body mass index (r=-0.38, P=.049) correlated with MHHS improvement. Alpha angle and abductor strength change were not correlated with change in MHHS or HOOS. Conclusion After MPT, patients reported improvements in pain and function that was associated with their ability to reduce hip adduction motion during functional tasks. Level of Evidence Therapy, level 2b. J Orthop Sports Phys Ther, Epub 16 Mar 2018. doi:10.2519/jospt.2018.7810.

Concepts: Waist-hip ratio, Hip, Body mass index, Magnetic resonance imaging, Adduction, Improve, Spearman's rank correlation coefficient, Better