Imaging of peripheral nerve causes of chronic buttock pain and sciatica.

Chronic buttock pain is a common and debilitating symptom, which severely impacts daily activities, sleep, and may affect athletic performance. Lumbar spine, posterior hip, or hamstring pathology are usually considered as the primary diagnoses; however, pelvic neural pathology may be a significant cause of chronic buttock pain, particularly if there are prolonged (>6 months) buttock and/or radicular symptoms. The subgluteal space is the site of most pelvic causes of neural-mediated buttock pain, primarily relating to entrapment neuropathy of the sciatic nerve (deep gluteal syndrome), although other nerves within the subgluteal space including the gluteal nerves, pudendal nerve, and posterior cutaneous nerve of thigh may also be involved. Additionally, cluneal nerve entrapment at the iliac crest may result in "pseudo-sciatica". Anatomical variants of the pelvic girdle muscles and functional factors, including muscle spasm and pelvic instability, may contribute to development of deep gluteal syndrome, along with neural senescence. Imaging findings primarily relate to the presence of sciatic neuritis and peri-sciatic pathology, including neural compression and peri-neural adhesions or fibrosis. This imaging review describes the causes, magnetic resonance imaging and ultrasound imaging findings and imaging-guided treatment of pelvic neural causes of chronic buttock pain and sciatica.

Angiosomal Vascular Occlusions, Deep-Tissue Pressure Injuries, and Competing Theories: A Case Report.

ABSTRACT: Compression of the soft tissue between a support surface and a bony prominence has long been the accepted primary mechanism of pressure injury (PrI) formation, with the belief that said compression leads to capillary occlusion, ischemia, and tissue necrosis. This explanation presupposes an "outside-in" pathophysiologic process of tissue damage originating at the local capillary level. Despite advances in prevention protocols, there remains a stubbornly consistent incidence of severe PrIs including deep-tissue injuries, the latter usually evolving into stage 4 PrIs with exposed bone or tendon. This article presents just such a perioperative case with the aim of providing further evidence that these more severe PrIs may result from ischemic insults of a named vessel within specific vascular territories (labeled as angiosomes). Pressure is indeed a factor in the formation of severe PrIs, but these authors postulate that the occlusion occurred at the level of a named artery proximal to the lesion. This vascular event was likely attributable to low mean arterial pressure. The authors suggest that the terminology proposed three decades ago to call both deep-tissue injuries and stage 4 PrIs "vascular occlusion pressure injuries" should be the topic of further research and expert consensus.

Appropriate sites for the measurement of the cross-sectional area of the gluteus maximus and the gluteus medius muscles in patients with hip osteoarthritis.

PURPOSE: To evaluate the relationship between the volume, cross-sectional area, and peak isometric muscle strength of the gluteus maximus and gluteus medius muscles in patients with hip osteoarthritis, and to use this information to identify effective sites for measurement of the cross-sectional area of these muscles. METHODS: Twenty-four patients with hip osteoarthritis were included. The muscle cross-sectional area and volume were calculated from magnetic resonance images. The cross-sectional area was calculated at three levels: the inferior point of the sacroiliac joint, just above the femoral head, and at the greatest muscle diameter. Peak isometric strength was assessed using hand-held dynamometry, using the extension and external rotation for the gluteus maximus and abduction and internal rotation for the gluteus medius. Measured outcomes were compared between the two muscles, and the association between muscle volume, cross-sectional area, and peak isometric muscle strength was evaluated using Pearson's correlation. RESULTS: Volume was correlated with the cross-sectional area in the gluteus maximus (r ≥ 0.707) and with the cross-sectional area (r ≥ 0.637) and peak isometric strength (r ≥ 0.477) in the gluteus medius. There was no difference between the cross-sectional area measured at the greatest muscle diameter and just above the femoral head (p = 0.503) for the gluteus maximus and at the inferior point of the sacroiliac joint (p = 0.651) for the gluteus medius. CONCLUSION: The cross-sectional area, when used to calculate the muscle volume, should be evaluated just above the femoral head for the gluteus maximus and at the inferior point of the sacroiliac joint for the gluteus medius.

Ischial tuberosity: new donor site for bone grafts in animal cleft research.

In the context of cleft repair in animal research in rat models, different areas can be used for bone grafting. The aim of the present study was to present the tuberosity of the ischium as a new donor site and to evaluate its quality in relation to an artificial alveolar cleft. Four weeks after creating experimental alveolar clefts in seven Wistar rats, the repair was performed in the now twelve-week-old male animals using bone blocks grafted from the ischial tuberosity. Two days before surgery and two as well as twenty-eight days after surgery, microCT scans were performed, and the grafted bone blocks were analyzed regarding height, width, thickness, and volume. Additionally, bone mineral density (BMD) and bone volume fraction (BV/TV) were measured in the repaired cleft. The mean bone volume of the graft was about 19.77 ± 7.77mm3. Immediately after jaw reconstruction the BMD and BV/TV were about 0.54 ± 0.05 g/cm3 and 54.9 ± 5.07% for the transplant and about 1.13 ± 0.08 g/cm3 and 94.5 ± 3.70%, respectively, for the surrounding bone. Four weeks later the BMD and BV/TV were about 0.57 ± 0.13 g/cm3 and 56.60 ± 13.70% for the transplant and about 11.17 ± 0.07 g/cm3 and 97.50 ± 2.15%, respectively, for the surrounding bone. A hip fracture was found in four of the animals after surgery. The ischial tuberosity offers large bone blocks, which are sufficient for cleft repair in the rat model. However, the bone quality regarding BMD and BV/TV is less compared with the surrounding bone of the alveolar cleft, even after a period of 4 weeks, despite recognizable renovation processes.

Pain Syndromes Secondary to Cluneal Nerve Entrapment.

PURPOSE OF REVIEW: The purpose of this review is to provide an overview of the cluneal nerves, present a summary of pain syndromes secondary to clunealgia, and evaluate current literature for diagnostic and treatment modalities. RECENT FINDINGS: Multiple trials and studies have reported success with numerous modalities ranging from nerve blocks, neuroablation, and even peripheral neuromodulation with varying degrees of clinical benefit. Cluneal nerve entrapment or chronic impingement can cause buttock pain or referred pain to nearby areas including the lower back, pelvic area, or even the lower extremities. Clunealgias and associated pain syndromes can often be challenging to diagnose and differentiate. An appreciation of the pathophysiology of clunealgias can assist with patient selection for interventional pain strategies targeted towards the cluneal nerves, including nerve blocks, neuroablation, and peripheral neuromodulation. More research is needed to better delineate the efficacy of these procedures for clunealgias.

Cross-cultural adaptation and validation of the Victorian Institute of Sports Assessment for gluteal tendinopathy questionnaire in Italian and investigation of the association between tendinopathy-related disability and pain.

BACKGROUND: The Victorian Institute of Sports Assessment for gluteal tendinopathy (VISA-G) questionnaire has recently been proposed as a condition-specific patient reported outcome measurement tool to assess the tendinopathy-related disability. AIM: The aim was to evaluate the reliability of the Italian version of the VISA-G questionnaire and its construct validity and to investigate the association between tendinopathy-related disability and pain. DESIGN: It consists in a cross-sectional study. SETTING: The location of the study was a university laboratory. POPULATION: We evaluated patients with gluteal tendinopathy (N.=38) and healthy controls (N.=38). METHODS: Subjects were asked to fill the VISA-G questionnaire twice to evaluate its reliability. The construct validity was evaluated by comparing the VISA score with the Oswestry Disability Index score. Moreover, pain intensity, extent and location were also investigated. RESULTS: The VISA-G scores showed non-significant changes in the median values and the values of intraclass correlation coefficient showed very high correlation between the first and second administration (ICC>0.90 in both populations). No significant correlations were found between VISA-G score and either pain extent (R=-0.05, P=0.76), or resting pain intensity (R=-0.13, P=0.45), or palpation pain intensity (R= 0.01, P=0.97). Conversely, a high (and significant) negative correlation was obtained between VISA-G score and Oswestry Disability Index score (R=-0.80, P<0.0001). CONCLUSIONS: These results indicated that the VISA-G Italian version presents excellent test-retest reliability. CLINICAL REHABILITATION IMPACT: The evaluation of gluteal tendinopathy-related disability through VISA-G can be useful for the prognostic assessment and/or follow-up of tendinopathy patients in combination with the pain drawing assessment of pain extent.

Seated buttocks anatomy and its impact on biomechanical risk.

AIM: The objective of this study was to describe the amount, types, and shapes of tissue present in the buttocks during sitting (i.e., seated buttocks soft tissue anatomy), and the impact of seated buttocks soft tissue anatomy on biomechanical risk. MATERIALS AND METHODS: The buttocks of 35 people, including 29 full-time wheelchair users with and without a history of pelvic pressure ulcers were scanned sitting upright on 3" of flat HR45 foam in a FONAR Upright MRI. Multi-planar scans were analyzed to calculate bulk tissue thickness, tissue composition, gluteus maximus coverage at the ischium, the contour of the skin, and pelvic tilt. RESULTS: Bulk tissue thickness varied from 5.6 to 32.1 mm, was composed mostly of adipose tissue, and was greatest in the able-bodied cohort. Skin contours varied significantly across status group, with wheelchair users with a history of pressure ulcers having tissue with a peaked contour with a radius of curvature of 65.9 mm that wrapped more closely to the ischium (thickness at the apex = 8.2 mm) as compared to wheelchair users with no pressure ulcer history (radius of curvature = 91.5 mm and apex thickness = 14.5 mm). Finally, the majority of participants presented with little to no gluteus coverage over their ischial tuberosity, regardless of status group. CONCLUSIONS: This study provides quantitative evidence that Biomechanical Risk, or the intrinsic characteristic of an individual's soft tissues to deform in response to extrinsic applied forces, is greater in individuals at greater risk for pressure ulcers.

A possible prediction of dystocia at the time of cesarean delivery: Gluteal muscle contracture, a single center experience from China.

The study assessed the pelvic dimensions by computed tomography (CT) performed for gluteal muscle contracture women, and evaluated the impact of malformations on several essential obstetric parameters.The CT pelvimetry was retrospectively performed in 25 gluteal muscle contracture women selected consecutively whether they had delivery history or not. Among the pelvic inlet plane, the mid plane and the outlet plane, 12 indicators including the transverse diameter of the pelvic inlet, the conjugate vera, the diagonal conjugate, the biischial diameter, the anteroposterior diameter of the middle pelvis, transverse outlet, the posterior sagittal diameter of outlet, the conjugate of the outlet, the anterior sagittal diameter of the outlet, the curvature and length of the sacrum, the angle of pubic arch were collected.Finally, the mean age of these women was 26.6 ±â€Š5.0 years. Most pelvises had anteroposterior elliptical appearance in inlet and size of the female pelvis. The most statistically different and most clinically significant indicator was the biischial diameter, gluteal muscle contracture women were 95.6 ±â€Š9.3 mm and the normal women from other study were 105.0 ±â€Š7.9 mm, the comparison showed a significant difference (P < .001).Generally, most gluteal muscle contracture women had features of anthropoid pelvis which were quite different from normal Chinese female. These results may serve as a basis for future studies to assess its utility and prognostic value for a safe vaginal delivery in gluteal muscle contracture women.

Gluteus medius dysfunction in females with chronic ankle instability is consistent at different walking speeds.

BACKGROUND: Patients with chronic ankle instability often present with altered gait mechanics compared to ankle sprain copers. There is increasing evidence to suggest proximal neuromuscular alterations contribute to the injury etiology, however little is known about how these changes manifest during gait. The purpose of this study was to investigate ipsilateral gluteus maximus and medius functional activity ratios throughout treadmill walking at three speeds (preferred, 120% preferred, and 1.35 m per second) in chronic ankle instability patients compared to copers. METHODS: 28 females (14 chronic ankle instability, 14 copers) walked at the three gait speeds in randomized order. Ground reaction forces and 10-s gluteal ultrasound clips were simultaneously recorded. Clips were reduced using ground reaction forces to extract 55 measurement frames. Normalized gluteal thickness measures were used to determine functional activity ratios. 2 × 3 analyses of variance were run to assess group and speed effects on gluteal outcomes throughout walking using statistical parametric mapping. Post-hoc t-tests, mean differences, and Cohen's d effect sizes were assessed for significant findings (P ≤ .05). FINDINGS: The chronic ankle instability group had significantly decreased gluteus medius activity throughout the entire gait cycle when compared to the coper group, independent of gait speed (P < .001, mean differences: 0.10-0.18; d: 1.00-3.17). There were no significant group or speed main effects, nor an interaction for gluteus maximus activity. INTERPRETATION: Gluteal dysfunction throughout walking was identified in chronic ankle instability. The coper group remained within healthy reference muscle activity ranges, suggesting that proximal muscle activation alterations are associated chronic ankle impairments.

How weakness of the tensor fascia lata and gluteus maximus may contribute to ACL injury: A new theory.

Anterior cruciate ligament (ACL) injuries are common in sports including a significant failure rate following reconstruction. The iliotibial band (ITB) is an important stabilizer of the lateral portion of the knee and also an important lateral rotator of the tibia. Both the tensor fascia lata (TFL) and gluteus maximus (Gmax) muscles insert into the ITB proximally. This paper describes a theory that implicates weakened TFL and Gmax muscles as possible contributors to anterolateral rotatory instability. If the TFL and Gmax are important contributors to anterolateral rotatory instability, physical therapists can emphasize assessing for their weakness and developing a rehabilitation program to restore their strength.

Could the tendon degeneration and the fatty infiltration of the gluteus medius affect clinical outcome in total hip arthroplasty?

PURPOSE: The aim of this prospective study was to perform a clinical and radiologic evaluation of patients undergoing total hip arthroplasty (THA). The hypothesis is that there is a correlation between the pre-operative degeneration state of the gluteal muscle-tendinous unit and the clinical outcome in terms of functional recovery. METHODS: Fifty-five patients have met inclusion criteria. All patients included in the sample were subjected to clinical evaluation. The ultrasound examination of the patients of the study was conducted and the following parameters were assessed: Thickness in mm of the gluteus medius tendon; Quality of the gluteus medius tendon; and Trophy and muscular composition. RESULTS: The degree of degeneration of the pre-operative tendon shows a negative statistical correlation with all the pre- and post-operative clinical scales, but presents statistical significance (p < 0.05) only with the post-operative Harris, the post-operative Oxford, the Harris and HOOS-modified post-operative, lameness, and Trendelenburg; it correlates positively with the quality of the macroscopic tendon detected intra-operatively, the degree of the pre-operative contralateral tendon, and the operated and contralateral pre-operative muscle (p < 0.05). The degree of fatty degeneration of the pre-operatively operated muscle correlates negatively (p < 0.05) with all pre- and post-operative clinical scales except for the pre-operative WOMAC and HOOS modified, with the lameness and the Trendelenburg sign; it correlates positively (p < 0.05) with age, the quality of the macroscopic tendon detected intra-operatively, degree of tendon degeneration, fatty infiltration of the contralateral pre- and post-operative muscle and of the post-operative operated muscle. CONCLUSION: Tendon degeneration and fatty infiltration of the gluteus medius muscle appeared to be determinants of the post-operative persistence of lameness and Trendelenburg sign positivity in patients undergoing hip arthroplasty.

The effect of a single high velocity low amplitude hip mobilization on strength in subjects with knee injuries.

BACKGROUND: Manual therapy have been used as a disinhibitory intervention to increase muscle activation before performing functional tasks that are limited by weakness. Knee injuries are commonly associated with weakness in quadriceps and gluteus. Currently, there is no evidence to support anecdotal experience that a hip distraction mobilization improves muscle performance in subjects with knee injuries and lower extremity weakness. OBJECTIVES: To determine if a hip distraction mobilization would result in an immediate change of maximal force output of the quadriceps and gluteus. DESIGN: Non-controlled observational pre-post design. METHODS: Forty individuals with knee pathology were included. Subjects underwent quadriceps, gluteus maximus, and gluteus medius muscle strength assessment before a single hip distraction of the symptomatic side. An immediate re-assessment of muscle strength of both symptomatic and asymptomatic sides followed the mobilization. RESULTS: /findings: Comparing pre-to post-mobilization strength on the symptomatic side, a significant increase was found with the gluteus maximus (average change = 2.0 kg [95%CI 0.6-3.4]; p < 0.01) but not gluteus medius (0.2 kg [-0.7-1.0]; p = 0.71) or quadriceps (0.1 kg [-1.4-1.7]; p = 0.86). When comparing the strength on the symptomatic side in subjects with weakness greater than the MDD95 (0.7-2.9 kg), a significant increase was again found for gluteus maximus (4.7 kg [2.6-6.8]; p < 0.01) but not for gluteus medius (0.2 kg [-1.0-1.4]; p = 0.71) or quadriceps (1.6 kg [-0.7-3.9]; p = 0.15). CONCLUSION: A single hip distraction resulted in a significant increase in gluteus maximus strength but did not produce a change in gluteus medius or quadriceps strength in subjects with knee injuries.

Do features of central sensitisation exist in Greater Trochanteric Pain Syndrome (GTPS)? A case control study.

BACKGROUND: Greater Trochanteric Pain Syndrome (GTPS), which is commonly due to Gluteal Tendinopathy, refers to pain over the lateral hip that can become persistent and disabling. Central nervous sensitisation has been implicated in upper limb tendinopathy, but no studies have investigated if it plays a role in GTPS. OBJECTIVES: To investigate if features of central sensitisation were present in people with GTPS. METHODS: Eighteen people with GTPS were matched with 18 healthy controls in this cross-sectional study. The VISA-G and Central Sensitisation Inventory (CSI) self-report questionnaires were completed and pressure pain detection thresholds (PPDTs) at local and remote sites were measured in all participants. Data were analysed for between-group differences using Mann-Whitney U tests. Correlation between CSI and PPDTs were assessed using Pearson correlation co-efficients. RESULTS: PPDT values were lower at local (symptomatic greater trochanter) and remote sites in the GTPS group, indicative of central sensitisation, resulting in statistically significant between-group differences. 44.4% of the GTPS group were classified as having symptoms of central sensitisation, based on the CSI. CONCLUSION: There is preliminary evidence of central sensitisation in people with GTPS. Results need to be validated using other objective quantitative sensory testing measures in larger samples.

Responsiveness of the Victorian Institute for Sport Assessment for Gluteal Tendinopathy (VISA-G), modified Harris hip and Oxford hip scores in patients undergoing hip abductor tendon repair.

BACKGROUND: A lack of consensus exists on which patient-reported outcome measures (PROMs) best evaluate change following hip abductor tendon (HAT) repair. OBJECTIVES: To compare the responsiveness of the Victorian Institute for Sport Assessment for Gluteal Tendinopathy (VISA-G), Oxford Hip (OHS) and modified Harris Hip (mHHS) scores in patients undergoing HAT repair. STUDY DESIGN: Prospective case series. METHODS: 56 patients underwent HAT repair and were evaluated pre-surgery and 3, 6 and 12 months post-operatively using the VISA-G, OHS, mHHS and a Global Rating of Change (GRC) scale. Internal and external responsiveness, the minimal clinically important change (MIC) and the presence of ceiling effects were evaluated. The extent to which VISA-G change was associated with mHHS and OHS change was investigated, as was the extent to which PROM changes were discriminatory for GRC improvement. RESULTS: All PROMs demonstrated large standardized effect sizes (>1), with the VISA-G demonstrating responsiveness similar to the mHHS and OHS. At 12 months, the GRC correlated similarly with VISA-G (0.42, 95% CI: 0.17-0.61), mHHS (0.44, 95% CI: 0.17-0.61) and OHS (0.53, 95% CI: 0.31-0.70) changes. Using a GRC anchor of ≥4, an MIC of 29/100, 29/91 (32/100) and 16/48 (33/100) was observed for the VISA-G, mHHS and OHS, respectively. At 12 months ceiling effects existed for the mHHS (18/56, 32.1%) and OHS (13/56, 23.2%), but not VISA-G (1/56, 1.8%). CONCLUSION: The VISA-G demonstrated acceptable responsiveness and was more resistant to ceiling effects, though demonstrated similar change scores and correlations with perceived improvement to the mHHS and OHS. CLINICAL TRIAL REGISTRATION: This research trial is registered in the Australian New Zealand Clinical Trials Registry (ACTRN12616001655437).

Gluteal Burns from a Car Seat Heater in a Neurologically Intact Patient: A Case Report.

BACKGROUND: Car seat heaters are an increasingly common amenity in vehicles in the United States, but they have been shown to place neurologically impaired patients at risk for significant burns. CASE REPORT: We discuss the case of a neurologically intact and otherwise healthy 49-year-old man who presented to the Emergency Department with second-degree gluteal and posterior upper thigh burns after using a car seat warmer for 8 consecutive hours. At no point during the course of his drive did he experience discomfort beyond feeling slightly warm. The patient was treated with supportive therapy and standard wound care, and he had a full recovery after 10 days. We review the pathophysiology of burns and discuss how seat heaters can place even neurologically intact patients at risk for significant burn injuries. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Our case is the first published report of a neurologically intact patient sustaining significant burns from the use of a car seat heater. This case illustrates that burn injuries can develop after prolonged exposure even at low temperatures. Emergency physicians should perform a careful skin examination on all patients presenting with gluteal discomfort in whom a history of car seat warmer use is obtained.

Identification and differentiation of gluteus medius tendon pathology using ultrasound and magnetic resonance imaging.

BACKGROUND: It has been suggested that imaging findings play a role in directing treatment for Greater Trochanteric Pain Syndrome. Structural diagnoses associated with Greater Trochanter Pain Syndrome include gluteal tendinosis, and partial- or full-thickness gluteal tendon tears. However, few studies have compared imaging to confirmed tendon pathology observed during surgery. OBJECTIVE: To investigate the ability of magnetic resonance and ultrasound imaging to identify the presence of a pathological gluteus medius tendon in comparison to surgical and histological findings. STUDY DESIGN: Cross-sectional study. METHODS: 26 participants undergoing gluteal tendon reconstruction surgery or hip arthroplasty were included. Prior to surgery, participants underwent both magnetic resonance (MR) (n = 23) and ultrasound (US) (n = 25) imaging. A radiologist (MR) and nuclear physicians (US) classified the gluteus medius tendon as normal, tendinosis (no tear), partial-thickness tear, or full-thickness tear. RESULTS: Ultrasound identified 17 out of the 19 pathological gluteus medius tendons correctly. However, 5 of the 6 normal tendons were incorrectly identified as exhibiting pathology on ultrasound. Magnetic resonance rated 11 out of 17 pathological tendons as abnormal, with 4 out of 6 normal tendons identified correctly. Both imaging modalities were poor at identifying and differentiating between tendinosis and partial-thickness tears. CONCLUSION: Both imaging modalities showed a reasonable ability to identify tendon pathology. While limited by sample size, these early findings suggest that both imaging modalities may be limited in identifying specific pathoanatomical diagnoses, such as partial-thickness tears. These limitations may misdirect treatment.

Detection of Gluteal Changes Using Ultrasound Imaging During Phases of Gait in Individuals With Medial Knee Displacement.

Context: Medial knee displacement (MKD) is a common risk factor for lower-extremity injury and is related to altered gluteal muscle activity. Ultrasound imaging (USI) is a reliable means to explore mechanical muscle activity; however, no information exists regarding USI of the gluteals during gait in an MKD population. Objective: To determine differences in USI gluteal muscle activity during gait in individuals with and without MKD. Design: Descriptive laboratory study. Setting: University research laboratory. Participants: Out of 28 participants, 14 exhibiting MKD unilaterally during a single-leg squat (19.36 [1.51] y, 169.73 [7.50] cm, and 62.01 [10.57] kg; 10 females) and 14 matched non-MKD subjects (20.29 [1.73] y, 167.24 [9.07] cm, and 67.53 [16.03] kg). Interventions: Bilateral B-mode USI of the gluteus maximus (Gmax) and gluteus medius (Gmed) muscles during quiet stance, heel strike, and a 10-second treadmill walking clip. Main Outcome Measures: Gluteal thickness measures normalized to quiet stance yielded activity ratios, and percentage of muscle thickness change was assessed between heel strike and quiet stance. Differences between groups were assessed with Cohen's d effect sizes with 95% confidence intervals. Activity ratios with 90% confidence intervals plotted on 10% intervals from 0% to 100% of gait were used to compare groups and limbs. A subsample of images was measured to determine intertester reliability. Results: USI revealed decreased Gmax and Gmed percent change at heel strike (%change = -9.57% [7.15%] and -8.76% [4.26%], respectively). The MKD limb compared with the contralateral limb exhibited decreased Gmed activity ratio at 30% of gait (MKD = 0.89 [0.056]; non-MKD = 1.01 [.052]). Intertester reliability was excellent for gluteus maximus (intraclass correlation coefficient = .987 [.014]) and Gmed (intraclass correlation coefficient = .989 [.013]) measurements. Conclusions: USI highlighted gluteal activity differences of MKD limbs during gait, which may contribute to inadequate hip stabilization during this daily repetitive task. These findings potentiate the use of USI as an intervention- or screening-based visual tool.

Hip Abductor and Adductor Muscles Activity Patterns During Landing After Anterior Cruciate Ligament Injury.

CONTEXT: Hamstring and quadriceps activity adaptations are well known in individuals with anterior cruciate ligament deficiency (ACLD) and reconstructed (ACLR) to potentially compensate for knee joint instability. However, few studies have explored hip muscles activity patterns after ACL injury. OBJECTIVE: To examine the activation characteristics of gluteus medius (GMED) and adductor longus in ACLR and ACLD subjects compared with controls. DESIGN: Case-control study. SETTING: Athletic training room and university lab. PARTICIPANTS: Twelve healthy and 24 ACL-injured (12 ACLR and 12 ACLD) recreationally active male volunteers. INTERVENTIONS: Surface electromyography of the GMED and adductor longus were recorded during a single-leg vertical drop landing and normalized to maximum voluntary isometric contractions. MAIN OUTCOME MEASURES: Preparatory and reactive muscle activity and coactivation were analyzed from 100 milliseconds prior to initial contact to 250 milliseconds postcontact. RESULTS: During reactive activity, ACL-injured (ACLR and ACLD) participants demonstrated significantly lower peak GMED activity compared with controls (F = 4.33, P = .02). In addition, ACLR participants exhibited significantly lower reactive GMED:adductor longus coactivation muscle activity compared with controls (F = 4.09, P = .03). CONCLUSION: Our findings suggest neuromuscular adaptations of the hip musculature are present in people at least 2 years from ACL injury. GMED activation exercises should be considered in designing rehabilitation programs for ACL-injured individuals.