Does Focused Gluteus Medius Muscle Stretching After Total Hip Arthroplasty Work? An Electromyographic Study.

BACKGROUND: The hypothesis of this randomized, prospective study was that focused stretching of the gluteus medius muscle, in addition to generalized physical therapy, is likely to improve muscle reaction time and positively impact the return to function of the patient after primary total hip arthroplasty (THA). METHODS: We prospectively recruited 28 patients undergoing primary THA from January 2021 to January 2023. The control group (13 patients) received a conventional rehabilitation protocol, while the intervention group (15 patients) received focused stretching exercises of the gluteus medius muscle in addition to the conventional rehabilitation protocol. Patients had preoperative and postoperative surface electromyography (sEMG) to assess muscle activity. RESULTS: Patients in the intervention group after surgery had better muscle activation according to sEMG during walking and during one leg stance compared to the control group. Also, patients from the intervention group had better strength of the gluteus medius muscle after surgery, but this did not reach statistical significance. CONCLUSIONS: The present prospective study demonstrated that implementation of focused gluteus medius muscle stretching results in statistically significantly higher muscle activation as measured by sEMG. The strength of the gluteus medius muscle is also higher as measured using a dynamometer, albeit not reaching statistical significance. Based on the findings of this sEMG study, it appears that focused stretching and strengthening of abductors muscles are beneficial.

Reduced Cross-Sectional Area of the Gluteus Medius Muscle is Associated With Decreased Activities of Daily Living in Older Adult Patients With Hip Fractures.

We investigated the association between the cross-sectional area (CSA) of the gluteus medius muscle (GMM) and activities of daily living in patients with hip fractures. This retrospective cohort study comprised 111 patients aged ≥65 years who underwent hip fracture rehabilitation. The CSA of the GMM was measured using computed tomography scans in the early stages of hospitalization. The group with decreased CSA of the GMM had a median GMI ≤17 cm2/m2 for male patients and ≤16 cm2/m2 for female patients. Patients in the group with decreased CSA of the GMM had lower functional independence measure gains than those in the control group. After adjusting for confounders, we found that decreased CSA of the GMM was significantly associated with lower functional independence measure gains (ß: -0.432, p < .001). In patients with hip fractures, decreased CSA of the GMM was associated with decreased activities of daily living.

A Gluteus Medius Muscle Biopsy to Confirm Amyloid Transthyretin Deposition in Wild-type Transthyretin Cardiac Amyloidosis: A Report of Two Cases.

In patients with wild-type transthyretin cardiac amyloidosis (ATTRwt-CA), the uptake of the tracer on technetium-99m-labeled pyrophosphate (99mTc-PYP) scintigraphy, which indicates amyloid transthyretin (ATTR) per se, is often observed in skeletal muscles, such as the abdominal oblique and gluteal muscles. Among extracardiac biopsies for confirming ATTR deposition in ATTRwt-CA, a 99mTc-PYP imaging-based computed tomography (CT)-guided core needle biopsy of the internal oblique muscle has relatively high sensitivity. In some patients, the 99mTc-PYP uptake is more pronounced in the gluteal muscles than in oblique muscles. We herein report two cases of ATTRwt-CA in which a CT-guided biopsy of the gluteus medius muscle with 99mTc-PYP uptake confirmed the presence of ATTR deposits.

Abductor muscle function after anterolateral approach in patients with unilateral end-stage hip osteoarthritis undergoing total hip arthroplasty: A prospective study.

Background: Total hip arthroplasty (THA) is a successful procedure for treating end-stage hip osteoarthritis (OA). Regarding the surgical approach for THA, the anterolateral (AL) approach, which requires anterior hemimyotomy of the gluteus medius muscle, has shown a long-term favorable outcome. However, to date, complete information related to hip abductor muscle outcomes after the AL approach is unavailable. This study therefore aimed to evaluate the postoperative outcome of patients who undergo THA using the AL approach in terms of hip abductor muscle recovery, pain, function, and muscle healing status. Methods: Twenty patients diagnosed with unilateral end-stage hip OA underwent cementless THA with the AL approach. All patient procedures were performed by a single surgeon. Preoperative and postoperative data were collected at 2-week, 6-week, 3-month, and 6-month follow-up periods. Hip abductor muscle power was measured via handheld dynamometer. The healing of the musculotendinous repair was evaluated with magnetic resonance imaging at 9 months. Results: After THA, hip abductor muscle power in the operated hip significantly increased as early as 3 months post-procedure when compared with the preoperative value (p < 0.05). The other parameters-including pain score, Harris hip score, and WOMAC score-significantly improved as early as 2 weeks post-operation (p < 0.05). In all patients, MRI scans showed good healing of the muscle repair site without a gap in the gluteus medius muscle. However, three patients (15%) had some fibrosis and tendon swelling at the repair site. Conclusion: This study demonstrated that patients with end-stage hip OA could experience significantly improved hip abductor motor function as early as 3 months after undergoing THA with the AL approach. Moreover, despite patients experiencing anterior hemimyotomy of the gluteus medius muscle, no significant complications emerged at the muscle repair site in the AL approach.

Effect of psoas and gluteus medius muscles attenuation on hip fracture type.

INTRODUCTION: Sarcopenia is defined as a progressive loss of muscle mass and function with increased age. The measurement of muscle mass and attenuation on the axial computed tomography (CT) scan has been reported to be a good indicator for sarcopenia in previous literature. This study aimed to compare muscle mass between the intertrochanteric fracture and femoral neck fracture groups by accurately measuring muscle mass around the hip joint using a CT scan. METHODS: The cases were matched according to age and gender on a 1-to-1 basis. As a result, a total of 400 patients, 200 patients in each group with the same age and gender characteristics, were included in the study. At the disc of L4-L5 level, the cross-sectional area (CSA) of the psoas muscle was evaluated, and at the disc of L5-S1 level, the CSA of the psoas, iliacus and gluteus medius muscles were evaluated. In addition, attenuation was evaluated using the average Hounsfield Unit (HU) for the specific area. RESULTS: The mean age of 400 patients (262 females, 138 male) included in the study was 78.49 ± 7.67 years. It was observed that the mean HU values of the patients in the femoral neck fracture group were significantly higher than the intertrochanteric fracture group (p < 0.001, p = 0.008; respectively). At the same time, the mean HU values of the gluteus medius muscle were higher in the femoral neck fracture group (p < 0.001), but in contrast with the psoas muscle, the CSA values of gluteus medius muscle were significantly higher in the intertrochanteric fracture group (p = 0.017). CONCLUSIONS: Fatty degeneration of the psoas muscle among the muscles around the hip may affect the type of hip fracture. Elderly patients with strong psoas muscles may experience femoral neck fracture due to contraction and torsion during falling.

Effects of Kinesio Taping and Rigid Taping on Gluteus Medius Muscle Activation in Healthy Individuals: A Randomized Controlled Study.

BACKGROUND: Gluteus medius muscle (GMed) dysfunctions may be associated with pain and functional problems in the lumbar spine and lower limbs. The study sought to assess the effects of applying kinesio taping (KT) and rigid taping (RT) on GMed in the dominant leg of healthy individuals. Furthermore, an attempt was made to indicate which of the applied exercises brought about the greatest activation of GMed. METHODS: The study included 90 individuals, with an average age of 21.79. The participants were randomly assigned to one of three groups: kinesio tape (KT), rigid tape (RT) and placebo tape (C). GMed activation was assessed using sEMG during the performance of such exercises as glute bridge, unilateral glute bridge, clamshell, pelvic drop and lunge. Each of the participants was examined three times-before taping, immediately after and 48 h after taping. RESULTS: Before taping, the greatest GMed activation on the dominant side was noted in clamshell (54.12 %MVIC), whereas the lowest GMed activation was observed in glute bridge (36.35 %MVIC). The comparison of results obtained before and immediately after taping in all the groups revealed a statistically significant increase in GMed activation (p < 0.05), while the comparison of results achieved before and 48 h after taping showed significant differences in glute bridge in groups KT and RT. In all the groups, the differences in results obtained in the other exercises were not significant. Taking into account each of the applied exercises, at none of the three stages of examination were the differences between the groups significant. CONCLUSIONS: Regardless of the type of taping applied (KT, RT, C), a significant increase in GMed activation was noted in all the exercises immediately after taping. At none of the stages of examination were the differences between the groups significant.

Easily misdiagnosed intramuscular hemangioma: a case report.

An intramuscular hemangioma is a benign vascular tumor that often occurs in the lower extremities. We herein report a rare case of an intramuscular hemangioma that occurred in the gluteus medius muscle and was misdiagnosed as lumbar disc herniation. A 36-year-old woman presented with incidental and infrequent pain of the left buttock. She was diagnosed with lumbar disc herniation and underwent treatment. Although her pain was slightly relieved, relapse soon occurred. X-ray examination and magnetic resonance imaging revealed a mass in the gluteus medius muscle. The mass was suspected to be a malignant tumor and was therefore resected. The final diagnosis was an intramuscular hemangioma. Her pain completely disappeared thereafter and did not recur. Patients with intramuscular hemangiomas usually have no specific symptoms; therefore, this tumor is often misdiagnosed. When a satisfactory treatment effect is not obtained, the diagnosis should be reassessed in a timely manner.

[Surgical repair of gluteus medius muscle in hip replacement surgery]. / Metodiki khirurgicheskogo lecheniia povrezhdenii srednei iagodichnoi myshtsy pri total'nom éndoprotezirovanii tazobedrennogo sustava.

Injury of gluteus medius muscle is a serious often complication after hip replacement surgery followed by pain, claudication and significant deterioration of the quality of life. Prevention of intraoperative injury of this muscle is especially relevant in young patients. Normal function of this muscle provides rapid rehabilitation and early postoperative recovery. However, hip replacement surgery through Hardinge's direct lateral approach is accompanied by fatty degeneration of gluteus medius muscle in 12-20% of cases. Moreover, two or more redo procedures lead to fatty degeneration of almost 70% of anterior and 40% of central muscular segment. Currently, there are many methods of surgical treatment of this complication including transosseous muscle fixation, endoscopic procedures, repair using Achilles tendon, gluteus maximus muscle, lateral head of quadriceps muscle and allografts. However, various publications devoted to this problem have certain disadvantages including short follow-up period, small sample size and often unsatisfactory outcomes. Therefore, the question of surgical repair of hip abductor function remains open.

Gluteus medius muscle decompression for buttock pain: a case-series analysis.

BACKGROUND: The causes of low back and buttock pain are variable. Elsewhere, we presented a surgical technical note addressing the gluteus medius muscle (GMeM) pain that elicited buttock pain treatable by surgical decompression. Here, we report minimum 2-year surgical outcomes of GMeM decompression for intractable buttock pain. METHODS: Between January 2014 and December 2015, we surgically treated 55 consecutive patients with a GMeM pain. Of these, 39 were followed for at least 2 years; they were included in this study. Their average age was 69.2 years; 17 were men and 22 were women. The affected side was unilateral in 24 patients and bilateral in the other 15 (total 54 sites). The mean follow-up period was 40.0 months (range 25-50 months). The severity of pre- and post-treatment pain was recorded on the numerical rating scale (NRS) and the Roland-Morris Disability Questionnaire (RDQ). RESULTS: Of the 39 patients, 35 also presented with leg symptoms. They were exacerbated by walking in all 39 patients and by prolonged sitting in 33 patients; 19 had a past history of lumbar surgery and 4 manifested failed back surgery syndrome. Repeat surgery for wider decompression was performed in 5 patients due to pain recurrence 15.8 months after the first operation. At the last follow-up, the symptoms were significantly improved; the average NRS fell from 7.4 to 2.1 and the RDQ score from 10.5 to 3.3 (p < 0.05). CONCLUSIONS: When diagnostic criteria are met, GMeM decompression under local anesthesia is a useful treatment for intractable buttock pain.

Effect of surgical approach for contralateral side hip arthroplasty in below knee amputees: a retrospective cohort study.

BACKGROUND: The gluteus medius muscle plays a very important role in the stability of the gait, especially in patients with amputation of the lower limbs. Therefore, choosing the appropriate type of approach for hip arthroplasty is very important. Hence, this study aimed to compare the outcomes and complications between the anterolateral approach (ALA) and posterior approach (PA) for hip arthroplasty in patients with contralateral below knee amputation. METHODS: From January 1999 to November 2014, 67 patients who underwent hip arthroplasty with contralateral below knee amputation were retrospectively analyzed. The study subjects were divided into two groups: the PA group (33 cases) and the ALA group (34 cases). The results of the clinical functional recovery with Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, Harris Hip Score, and activity of daily living scale were compared between the two groups. During the follow-up period, complications related to gait such as fall, dislocation, and periprosthetic fractures (PPFs) were investigated. RESULTS: The Harris Hip Score (p = 0.024) and the activity of the daily living scale (p = 0.043) of the ALA group were significantly lower at 3 months compared to the PA group, but no significant difference was observed between the two groups from 6 months postoperatively to the last follow-up. The WOMAC score was not significantly different between the two groups. Within 3 months after surgery, falls occurred in 3 cases in the PA group and in 11 cases in the ALA group (p = 0.019) Dislocation and PPF were caused by prosthesis-related trauma. Two dislocations and 1 PPF occurred 8 years postoperatively in the PA group. PPF occurred in 3 patients in the ALA group, of which 2 occurred within 3 months after surgery. CONCLUSION: Orthopedic surgeons should pay particular attention in patients with hip arthroplasty on the contralateral side hip who had below knee amputation because functional recovery is delayed until 3 months after ALA compared with PA.

Differences in foetal topographical anatomy between insertion sites of the iliopsoas and gluteus medius muscles into the proximal femur: a consideration of femoral torsion.

BACKGROUND: Prenatal twisting of the femoral neck seems to result in an angle of anteversion or torsion, but the underlying process has not been elucidated. MATERIALS AND METHODS: This study analysed sagittal, frontal and horizontal sections of 34 embryo and foetal specimens of gestational age (GA) 6-16 weeks (crown-rump length 21-130 mm). At GA 6-7 weeks, the iliopsoas (IP) and gluteus medius (GME) muscles were inserted into the anterior and posterior aspects of the femur, respectively, allowing both insertions to be viewed in a single sagittal section. RESULTS: At GA 8 weeks, the greater trochanter and the femoral neck angle became evident, and the GME tendon was inserted into the upper tip of the trochanter. At GA 9 weeks, the location of IP insertion was to the medial side of the GME insertion. After 9 weeks, the IP insertion consisted of a wavy, tendino- us part of the psoas muscle and another part of the iliacus muscle, with many fibres of the latter muscle attached to the joint capsule. After GA 12 weeks, the IP was inserted into the anteromedial side of the greater trochanter, while the aponeurotic insertion of the GME wrapped around the trochanter. At GA 15-16 weeks, a deep flexion at the hip joint caused an alteration in the relative heights of the lesser and greater trochanter, with the former migrating from the inferior to the slightly superior side. CONCLUSIONS: These findings indicate that twisting of the femoral neck started at GA 8-9 weeks.

Surgical treatment of middle cluneal nerve entrapment neuropathy: technical note.

OBJECTIVE The etiology of low-back pain (LBP) is heterogeneous and is unknown in some patients with chronic pain. Superior cluneal nerve entrapment has been proposed as a causative factor, and some patients suffer severe symptoms. The middle cluneal nerve (MCN) is also implicated in the elicitation of LBP, and its clinical course and etiology remain unclear. The authors report the preliminary outcomes of a less invasive microsurgical release procedure to address MCN entrapment (MCN-E). METHODS The authors enrolled 11 patients (13 sites) with intractable LBP judged to be due to MCN-E. The group included 3 men and 8 women ranging in age from 52 to 86 years. Microscopic MCN neurolysis was performed under local anesthesia with the patient in the prone position. Postoperatively, all patients were allowed to walk freely with no restrictions. The mean follow-up period was 10.5 months. LBP severity was evaluated on the numerical rating scale (NRS) and by the Japanese Orthopaedic Association (JOA) and the Roland-Morris Disability Questionnaire (RDQ) scores. RESULTS All patients suffered buttock pain, and 9 also had leg symptoms. The symptoms were aggravated by standing, lumbar flexion, rolling over, prolonged sitting, and especially by walking. The numbers of nerve branches addressed during MCN neurolysis were 1 in 9 patients, 2 in 1 patient, and 3 in 1 patient. One patient required reoperation due to insufficient decompression originally. There were no local or systemic complications during or after surgery. Postoperatively, the symptoms of all patients improved statistically significantly; the mean NRS score fell from 7.0 to 1.4, the mean RDQ from 10.8 to 1.4, and the mean JOA score rose from 13.7 to 23.6. CONCLUSIONS Less invasive MCN neurolysis performed under local anesthesia is useful for LBP caused by MCN-E. In patients with intractable LBP, MCN-E should be considered.

Treatment of Extensive Gluteus Muscle Tears With Transosseous Fixation and a Nonresorbable Collagen Patch.

BACKGROUND: Extensive tearing of the gluteus muscles (spontaneous or subsequent to hip arthroplasty) is difficult to treat. We are carrying out osseous fixation with securement of the suture anchor by a nonresorbable collagen patch. The objective of this study is to examine the follow-up data of 30 patients and to assess whether the clinical outcomes depended on the extent of the fatty degeneration of the gluteus medius. METHODS: Thirty patients (28 female and 2 male) with a mean age of 76.8 ± 4.3 years (68-83 years) were followed for a mean of 46.8 ± 23.1 months (24-101 months). RESULTS: Pain improved significantly from a preoperative visual analog scale score of 7.0 ± 1.52 (6-10) to 0.83 ± 0.77 (0-3) 24-month postoperative. The gluteus medius muscle force increased from 2.09 ± 0.81 to 3.3 ± 0.78 using the British Medical Research Council Scale. All patients exhibited a severe limp before the operation. Postoperatively, only 5 patients had a severe limp, while 14 exhibited a mild limp and 11 no limp at all. The modified Harris Hip Score increased from a preoperative value of 44.5 ± 4.2 (26-66) to a value of 81.1 ± 7.79 (60-100) 24-month postoperative. The functional results were dependent on the level of fatty degeneration of the muscle. CONCLUSION: The first results for this surgical technique appear to be very promising for the treatment of extensive tearing of the gluteus musculature that has a degree of fatty degeneration less than 75%.

A porcine gluteus medius muscle genome-wide transcriptome analysis: dietary effects of omega-6 and omega-3 fatty acids on biological mechanisms.

BACKGROUND: The level of omega-6 and omega-3 polyunsaturated fatty acids can affect many cellular systems and function via nuclear receptors or the bioactive lipid regulation of gene expression. The objective of this study was to investigate changes in the muscle transcriptome and the biological functions regulated by increased consumption of omega-3 and omega-6 fatty acids in the pig gluteus medius muscle. RESULTS: The transcriptome of the gluteus medius muscle was studied for pigs subjected to either a control diet or a diet supplemented with linseed and rapeseed oil to increase polyunsaturated fatty acid content. Next-generation sequencing (NGS) was used to generate the muscle tissue transcriptome database pointing differentially expressed genes (DEG). Comparative expression analyses identified 749 genes significantly differing at least in the twofold of change between two groups of animals fed with divergent level of omega-3 and omega-6 fatty acids. The expression of 219 genes was upregulated, and the expression of 530 genes was downregulated in the group of pigs supplemented with omega-3 and omega-6 fatty acids in relation to control group pigs. Results of RNA-seq indicated a role of fatty acid in the regulation of the expression of genes which are essential for muscle tissue development and functioning. Functional analysis revealed that the identified genes were important for a number of biological processes including inflammatory response, signaling, lipid metabolism, and homeostasis. CONCLUSIONS: Summarizing, obtained results provide strong evidence that omega-6 and omega-3 fatty acids regulate fundamental metabolic processes in muscle tissue development and functioning.

Superior Cluneal Nerve Entrapment Neuropathy and Gluteus Medius Muscle Pain: Their Effect on Very Old Patients with Low Back Pain.

OBJECTIVE: In the very elderly, their general condition and poor compliance with drug regimens can render the treatment of low back pain (LBP) difficult. We report the effectiveness of a less-invasive treatment for intractable LBP from superior cluneal nerve entrapment neuropathy (SCN-EN) and gluteus medius muscle (GMeM) pain. PATIENTS AND METHODS: Between April 2013 and March 2015, we treated 17 consecutive elders with LBP, buttock pain, and leg pain. They were 4 men and 13 women ranging in age from 85 to 91 years (mean 86.6 years). We carefully ascertained that their symptoms were attributable to SCN-EN and GMeM pain. The median follow-up period was 21.5 ± 12.2 months (range 2-35 months). RESULTS: SCN-EN was diagnosed in 15 patients (28 sites) and GMeM pain in 14 (27 sites). In 5 patients, we obtained symptom control by local block (Numerical Rating Scale for LBP: declined from 7.8 to 0.8 [P < 0.05], Roland-Morris Disability Questionnaire score: declined from 16.5 to 5.2). The other 12 were operated under local anesthesia (SCN neurolysis, GMeM decompression). As 3 patients reported the persistence of leg pain postoperatively, they subsequently underwent peroneal nerve neurolysis and surgery for tarsal tunnel syndrome. These treatments resulted in significantly symptom abatement (Numerical Rating Scale: from 8.2 to 1.7, Roland-Morris Disability Questionnaire score: from 12.8 to 8.6; P < 0.05). CONCLUSIONS: Even very old patients with intractable LBP, buttock pain, and leg pain due to SCN-EN or GMeM pain can be treated successfully by peripheral block and less-invasive surgery under local anesthesia.

Effect of motor control training on hip muscles in elite football players with and without low back pain.

OBJECTIVES: Previous research has shown that motor control training improved size and function of trunk muscles in elite football players with and without low back pain (LBP). Imbalances in hip muscles have been found in athletes with LBP and it is not known if motor control training can change these muscles. This study investigated if a motor control intervention program affected hip muscle size in elite football players with and without LBP. DESIGN: Panel-randomised intervention design. METHODS: Forty-six players from one club in the Australian Football League (AFL) participated in a motor control training program delivered across the season as a stepped-wedge intervention design with 3 treatment arms: 15 weeks intervention, 8 weeks intervention and a wait-list control who received 7 weeks intervention toward the end of the playing season. Presence of LBP was assessed by interview and physical examination. Cross-sectional areas of iliacus, psoas, iliopsoas, sartorius, gluteus minimus, and gluteus medius muscles were measured from magnetic resonance images taken at 3 time points during the season. RESULTS: Iliopsoas, sartorius and gluteus medius muscle size increased for players who received intervention (p<0.05). For players with current LBP, sartorius and gluteus medius muscle size increased for those who received motor control training (p<0.05). CONCLUSIONS: Motor control training programs aimed at the lumbo-pelvic region also benefit the hip muscles. For players with current LBP, the intervention mitigated sartorius muscle atrophy and increased gluteus medius muscle size. These findings may help guide the management of LBP in elite football players.

Decompression of the gluteus medius muscle as a new treatment for buttock pain: technical note.

PURPOSE: The clinical features and etiology of low back pain and buttock pain remain poorly understood. We report ten patients with buttock pain who underwent gluteus medius muscle (GMeM) decompression under local anesthesia. METHODS: Between December 2012 and November 2013 we surgically treated ten patients (four men, six women; mean age 65.1 years) for buttock pain. The affected side was unilateral in seven and bilateral in three patients (total sites, n = 13). The interval from symptom onset to treatment averaged 174 months; the mean postoperative follow-up period was 24 months. Decompression of the tight gluteal aponeurosis over the GMeM was performed under local anesthesia. Assessment of the clinical outcomes was on the numeric rating scale (NRS) for low back pain (LBP), the Japanese Orthopedic Association (JOA) score, and the Roland-Morris Disability Questionnaire (RDQ) score before and at the latest follow-up after treatment. RESULTS: There were no intraoperative surgery-related complications. The buttock pain of all patients was improved after surgery; their NRS decreased from 7.0 to 0.8 and JOA and RMDQ scores indicated significant improvement (p < 0.05). CONCLUSION: In patients with buttock pain, pain around the GMeM should be considered as a causative factor. Less invasive surgery with cutting and opening of the tight gluteal aponeurosis over the GMeM under local anesthesia yielded excellent clinical outcomes.

Preoperative gluteus medius muscle atrophy as a predictor of walking ability after total hip arthroplasty.

PURPOSE: To elucidate the relation between certain preoperative physical parameters and walking with a limp after total hip arthroplasty (THA) and determine whether it is possible to predict the walking ability of patients 6 months after THA. METHODS: The subjects of this study comprised 74 female patients who had undergone unilateral THA. Before surgery, the hip abductor and knee extensor strengths were measured, the cross-sectional areas (CSAs) of the gluteus medius and rectus abdominis muscles were measured, and the Timed Up and Go test was conducted. The patients were then divided into two groups according to gait observation results 6 months postoperatively: walking without a limp (n=37) and walking with a limp (n=37). RESULTS: The discriminating criteria between the two groups were age (61 years), CSA of the gluteus medius muscle (2000 mm2), and CSA of the rectus abdominis muscle (340 mm2). In the multiple logistic regression analysis, the gluteus medius muscle was the only significant predictor of limping after THA (ß=1.64, R2=0.19, p<0.01). CONCLUSIONS: The results of the present study suggest that preoperative atrophy of the gluteus medius is an useful indicator for predicting walking with a limp 6 months postoperatively.

Light exercise causes adaptive changes in muscles of young Brasileiro de Hipismo horses / Atividade física leve causa mudanças adaptativas musculares em eqüinos jovens da raça Brasileiro de Hipismo

This study aimed to determine the changes in the Gluteus medius of 4 year-old Brasileiro de Hipismo (BH) horses submitted to light physical activity for 10 months. The study involved 11 horses from the "Nove de Julho" Battalion of the Military Police of São Paulo State (PM-SP). Percutaneous muscle biopsy was performed in horses at maintenance and in those that had participated in routine police work for 10 months with the PM-SP. Fragments of the left Gluteus medius muscle was removed at depths of 20mm and 60mm. To determine the fiber types, the histochemical analyses were performed for myofibrillar adenosine triphosphatase (mATPase) and nicotinamide adenine dinucleotide tetrazolium reductase (NADH-TR). The morphometry of the fibers was performed by calculating the cross sectional area (CSA), relative frequency distribution (F) and relative cross-sectional area (RCSA). After the period of physical activity, type IIA fibers showed an increase in F and RCSA at both depths. The type I fibers showed a decrease in F at a depth of 60mm and the type IIX fibers showed no change in F at the two depths. With regard to the results for RCSA, type I and IIX fibers also did not show alterations after 10 months of light physical activity. Low intensity physical activity produced significant adaptations in the Gluteus medius muscle of horses of the BH breed, including changes in metabolic and contractile properties as evidenced by the increase in the area occupied by type IIA fibers at both depths of the biopsy.

Este estudo objetivou determinar as adaptações do músculo Gluteus medius de cavalos da raça Brasileiro de Hipismo (BH), que participaram de atividades físicas leves por 10 meses. Foram utilizados 11 eqüinos, machos, da raça BH e com idade de 4 anos, provenientes do "Batalhão Nove de Julho" da Polícia Militar do Estado de São (PM-SP). Realizou-se a biópsia muscular percutânea nos animais inativos e, após participarem das atividades de ronda e policiamento desenvolvido pela PM-SP por 10 meses, foram retirados fragmentos do músculo Gluteus medius nas profundidades de 20mm e 60mm. Para a determinação dos tipos de fibra muscular, foram feitas análises histoquímicas por meio das técnicas de adenosina trifosfatase miofibrilar (mATPase) e nicotinamida adenina dinucleotídeo tetrazólio redutase (NADH-TR). Na análise morfométrica das fibras, calculou-se a área de secção transversal (AST), a freqüência média (F) e a área de secção transversal relativa (ASTR). Após o período de atividade física, as fibras tipo IIA apresentaram aumento da F e da ASTR nas duas profundidades. As fibras tipo I apresentaram diminuição da F na profundidade de 60mm e as fibras tipo IIX não sofreram alteração da F nas duas profundidades. A ASTR das fibras tipo I e IIX não apresentaram alteração após os 10 meses. A atividade física de baixa intensidade produziu adaptações significativas no músculo Gluteus medius de cavalos da raça BH, incluindo mudança nas propriedades metabólicas e contráteis evidenciadas pelo aumento da área ocupada pelas fibras tipo IIA, nas duas profundidades de biópsia.