Greater trochanter of the hip: attachment of the abductor mechanism and a complex of three bursae--MR imaging and MR bursography in cadavers and MR imaging in asymptomatic volunteers

Ultrasound-Guided Hip Procedures

This article describes the techniques for performing ultrasound-guided procedures in the hip region, including intra-articular hip injection, iliopsoas bursa injection, greater trochanter bursa injection, ischial bursa injection, and piriformis muscle injection. The common indications, pitfalls, accuracy, and efficacy of these procedures are also addressed.

Greater Trochanteric Pain Syndrome

Patients who have lateral hip pain historically have been diagnosed with trochanteric bursitis and treated with nonsteroidal anti-inflammatory medications, corticosteroid injections, and physical therapy. Although this strategy is effective for most patients, a substantial number of patients continue to have pain and functional limitations. Over the past decade, our understanding of disorders occurring in the peritrochanteric space has increased dramatically. Greater trochanteric pain syndrome encompasses trochanteric bursitis, external coxa saltans (ie, snapping hip), and abductor tendinopathy. A thorough understanding of the anatomy, examination findings, and imaging characteristics aids the clinician in treating these patients. Open and endoscopic treatment options are available for use when nonsurgical treatment is unsuccessful.

Prevalence and pattern of gluteus medius and minimus tendon pathology and muscle atrophy in older individuals using MRI

PURPOSE

To evaluate gluteus medius and minimus tendon pathology and muscle atrophy in older individuals using MRI.

METHODS

A retrospective MRI study of 185 individuals was performed. The inclusion criterion was age ≥50. Exclusion criteria were hip surgery, fracture, infection, tumor, or inadequate image quality. Greater trochanteric bursitis was graded none, mild, moderate, or severe. Gluteus medius, gluteus minimus, and iliopsoas tendinopathy was graded normal, tendinosis, low-grade partial tear, high-grade partial tear, or full thickness tear. Gluteus medius, gluteus minimus, tensor fascia lata, and iliopsoas muscle atrophy was scored using a standard scale. Insertion site of tendinopathy and location of muscle atrophy were assessed. Descriptive and statistical analysis was performed.

RESULTS

There was increasing greater trochanteric bursitis and gluteus medius and minimus tendinopathy and atrophy with advancing age with moderate to strong positive associations (p < 0.0001) for age and tendinopathy, age and atrophy, bursitis and tendinopathy, and tendinopathy and atrophy for the gluteus medius and minimus. There is a weak positive association (p < 0.0001) for age and tensor fascia lata atrophy, and no statistically significant association between age and tendinopathy or between age and atrophy for the iliopsoas. Fisher's exact tests were statistically significant (p < 0.0001) for insertion site of tendon pathology and location of muscle atrophy for the gluteus medius.

CONCLUSIONS

Gluteus medius and minimus tendon pathology and muscle atrophy increase with advancing age with progression of tendinosis to low-grade tendon tears to high-grade tendon tears. There is an associated progression in atrophy of these muscles, which may be important in fall-related hip fractures.

A review of surgical repair methods and patient outcomes for gluteal tendon tears

Advanced hip imaging and surgical findings have demonstrated that a common cause of greater trochanteric pain syndrome (GTPS) is gluteal tendon tears. Conservative measures are initially employed to treat GTPS and manage gluteal tears, though patients frequently undergo multiple courses of non-operative treatment with only temporary pain relief. Therefore, a number of surgical treatment options for recalcitrant GTPS associated with gluteal tears have been reported. These have included open trans-osseous or bone anchored suture techniques, endoscopic methods and the use of tendon augmentation for repair reinforcement. This review describes the anatomy, pathophysiology and clinical presentation of gluteal tendon tears. Surgical techniques and patient reported outcomes are presented. This review demonstrates that surgical repair can result in improved patient outcomes, irrespective of tear aetiology, and suggests that the patient with "trochanteric bursitis" should be carefully assessed as newer surgical techniques show promise for a condition that historically has been managed conservatively.

Cystic lesion around the hip joint

This article presents a narrative review of cystic lesions around the hip and primarily consists of 5 sections: Radiological examination, prevalence, pathogenesis, symptoms, and treatment. Cystic lesions around the hip are usually asymptomatic but may be observed incidentally on imaging examinations, such as computed tomography and magnetic resonance imaging. Some cysts may enlarge because of various pathological factors, such as trauma, osteoarthritis, rheumatoid arthritis, or total hip arthroplasty (THA), and may become symptomatic because of compression of surrounding structures, including the femoral, obturator, or sciatic nerves, external iliac or common femoral artery, femoral or external iliac vein, sigmoid colon, cecum, small bowel, ureters, and bladder. Treatment for symptomatic cystic lesions around the hip joint includes rest, nonsteroidal anti-inflammatory drug administration, needle aspiration, and surgical excision. Furthermore, when these cysts are associated with osteoarthritis, rheumatoid arthritis, and THA, primary or revision THA surgery will be necessary concurrent with cyst excision. Knowledge of the characteristic clinical appearance of cystic masses around the hip will be useful for determining specific diagnoses and treatments.

An evidence-based review of hip-focused neuromuscular exercise interventions to address dynamic lower extremity valgus

Deficits in proximal hip strength or neuromuscular control may lead to dynamic lower extremity valgus. Measures of dynamic lower extremity valgus have been previously shown to relate to increased risk of several knee pathologies, specifically anterior cruciate ligament ruptures and patellofemoral pain. Therefore, hip-focused interventions have gained considerable attention and been successful in addressing these knee pathologies. The purpose of the review was to identify and discuss hip-focused exercise interventions that aim to address dynamic lower extremity valgus. Previous electromyography, kinematics, and kinetics research support the use of targeted hip exercises with non-weight-bearing, controlled weight-bearing, functional exercise, and, to a lesser extent, dynamic exercises in reducing dynamic lower extremity valgus. Further studies should be developed to identify and understand the mechanistic relationship between optimized biomechanics during sports and hip-focused neuromuscular exercise interventions.

Evolution of the human hip. Part 2: muscling the double extension

Part 1 of this article outlined the extensive osseous adaptations around the hip that occurred in the development of a habitual bipedal gait in modern humans. The shortest summary of these osseous changes is 'double extension', i.e. extension of both the hip joint and the lumbar spine. Not surprisingly, these osseous changes went hand in hand with major muscular changes. The primary changes that accompanied the double extension were changes in relative muscle volume for the quadriceps, gluteus maximus and hamstrings, changes in moment arms for the iliopsoas, gluteus maximus and hamstrings, a change in function for the gluteus medius and minimus, while the functional anatomy of the adductors and hip rotators changed only slightly. The effect of these osseous and muscular changes was improved energy efficiency of human bipedal walking and (long distance) running. However, this occurred at the expense of maximum power, characteristic for activities such as tree climbing (in the apes), but equally so for sprinting. Recognizing these changes and their consequences may help us better understand and treat soft-tissue disorders around the hip.

Benefit of cup medialization in total hip arthroplasty is associated with femoral anatomy

BACKGROUND

Medialization of the cup with a respective increase in femoral offset has been proposed in THA to increase abductor moment arms. Insofar as there are potential disadvantages to cup medialization, it is important to ascertain whether the purported biomechanical benefits of cup medialization are large enough to warrant the downsides; to date, studies regarding this question have disagreed.

QUESTIONS/PURPOSES

The purpose of this study was to quantify the effect of cup medialization with a compensatory increase in femoral offset compared with anatomic reconstruction for patients undergoing THA. We tested the hypothesis that there is a (linear) correlation between preoperative anatomic parameters and muscle moment arm increase caused by cup medialization.

METHODS

Fifteen patients undergoing THA were selected, covering a typical range of preoperative femoral offsets. For each patient, a finite element model was built based on a preoperative CT scan. The model included the pelvis, femur, gluteus minimus, medius, and maximus. Two reconstructions were compared: (1) anatomic position of the acetabular center of rotation, and (2) cup medialization compensated by an increase in the femoral offset. Passive abduction-adduction and flexion-extension were simulated in the range of normal gait. Muscle moment arms were evaluated and correlated to preoperative femoral offset, acetabular offset, height of the greater trochanter (relative to femoral center of rotation), and femoral antetorsion angle.

RESULTS

The increase of muscle moment arms caused by cup medialization varied among patients. Muscle moment arms increase by 10% to 85% of the amount of cup medialization for abduction-adduction and from -35% (decrease) to 50% for flexion-extension. The change in moment arm was inversely correlated (R(2) = 0.588, p = 0.001) to femoral antetorsion (anteversion), such that patients with less femoral antetorsion gained more in terms of hip muscle moments. No linear correlation was observed between changes in moment arm and other preoperative parameters in this series.

CONCLUSIONS

The benefit of cup medialization is variable and depends on the individual anatomy.

CLINICAL RELEVANCE

Cup medialization with compensatory increase of the femoral offset may be particularly effective in patients with less femoral antetorsion. However, cup medialization must be balanced against its tradeoffs, including the additional loss of medial acetabular bone stock, and eventual proprioceptive implications of the nonanatomic center of rotation and perhaps joint reaction forces. Clinical studies should better determine the relevance of small changes of moment arms on function and joint reaction forces.

Greater trochanter pain syndrome: a descriptive MR imaging study

OBJECTIVE

Greater trochanter pain syndrome (GTPS) is a diverse clinical entity caused by a variety of underlying conditions. We sought to explore the impact of (1) hip morphology, namely the center-edge angle (CEa) and femoral neck-shaft (NSa) angle, (2) hip abductor tendon degeneration, (3) the dimensions of peritrochanteric edema and (4) bursitis, on the presence of GTPS, using MR imaging.

MATERIALS AND METHODS

The presence of pain was prospectively assessed blindly by the senior author. CEa and NSa were blindly measured in 174 hip MR examinations, after completion of the clinical evaluation by another evaluator. The existence and dimensions of T2 hyperintensity of the peritrochanteric soft tissues, the existence and dimensions of bursae, as well as degeneration and tearing of gluteus tendons were also recorded.

RESULTS

Out of 174 examinations, 91 displayed peritrochanteric edema (group A) and 34 bursitis, all with peritrochanteric edema (group B). A number of 78 patients from both A and B groups, showed gluteus medius tendon degeneration and one tendon tear. CEa of groups A and B were 6° higher than those of normals (group C, P=0.0038). The mean age of normals was 16.6 years less than in group A and 19.8 years less than in group B (P<0.0001). Bursitis was associated with pain with a negative predictive value of 97% (P=0.0003).

CONCLUSION

Acetabular morphology is associated with GTPS and the absence of bursitis was proved to be clinically relevant. Peritrochanteric edema alone was not associated with local pain.

Development of a method for measuring femoral torsion using real-time ultrasound

Excessive femoral torsion has been associated with various musculoskeletal and neurological problems. To explore this relationship, it is essential to be able to measure femoral torsion in the clinic accurately. Computerized tomography (CT) and magnetic resonance imaging (MRI) are thought to provide the most accurate measurements but CT involves significant radiation exposure and MRI is expensive. The aim of this study was to design a method for measuring femoral torsion in the clinic, and to determine the reliability of this method. Details of design process, including construction of a jig, the protocol developed and the reliability of the method are presented. The protocol developed used ultrasound to image a ridge on the greater trochanter, and a customized jig placed on the femoral condyles as reference points. An inclinometer attached to the customized jig allowed quantification of the degree of femoral torsion. Measurements taken with this protocol had excellent intra- and inter-rater reliability (ICC2,1 = 0.98 and 0.97, respectively). This method of measuring femoral torsion also permitted measurement of femoral torsion with a high degree of accuracy. This method is applicable to the research setting and, with minor adjustments, will be applicable to the clinical setting.

Ultrasound evaluation of greater trochanter pain syndrome in patients with spondyloarthritis: are there any specific features?

Although greater trochanter pain syndrome (GTPS) is a prevalent cause of musculoskeletal pain in the general population, there is lack of imaging studies searching for differential features of inflammatory enthesitis in GTPS. We analyzed the features of GTPS using sonography and magnetic resonance imaging (MRI) to identify useful differential signs between spondyloarthritis (SpA) and other inflammatory or non-inflammatory musculoskeletal diseases. All patients with unilateral GTPS attended by our Arthritis Unit between February 2011 and March 2012 were included. Patients were classified as having SpA or mechanical (without inflammatory musculoskeletal disease) GTPS. Rheumatoid arthritis (RA) patients were also included as inflammatory controls. Ultrasound scans of the painful and contralateral, asymptomatic, greater trochanter were made. We assessed the gluteus medius and gluteus minimus tendons for signs suggestive of tendinopathy. Random MRI of the same regions was made in a subgroup of patients to validate the ultrasound findings. A total of 107 patients with unilateral GTPS were included, of whom 96 were female, with a mean age of 61.6 years: 34 had SpA, 48 had non-inflammatory musculoskeletal disease, and 25 had RA. No specific sonographic features for SpA were found. Pathological findings were more frequent in patients without musculoskeletal inflammatory disease (mainly bursitis and erosions). A large number of alterations were found in the asymptomatic side (around 40 % had cortical irregularities and 20 % bursa effusion). Signs of enthesopathy were more prevalent in the gluteus minimus tendon, regardless of the diagnosis (54.2 % had erosions, 39.3 % bursitis, 38.3 % calcifications and 37.4 % tendinosis). No patient had power Doppler signal. Age was the main factor in the appearance of tendinopathy. MRI confirmed the changes detected by ultrasound in all 40 patients evaluated. GTPS in patients with SpA has similar sonographic findings to those observed in patients with RA and patients without musculoskeletal inflammatory disease. Neither sonography nor MRI was clinically useful in classifying GTPS as a manifestation of SpA.

Acute calcific tendinitis of the gluteus medius: an uncommon source for back, buttock, and thigh pain

OBJECTIVE

This study was conducted to describe the imaging features and clinical manifestations in acute calcific tendinitis (CaT) of the gluteus medius muscle (GMe).

METHODS

A retrospective analysis was conducted, aimed at six patients with acute calcific tendinitis of the gluteus medius muscle (CaT-GMe), who were seen between January 2011 and December 2012. Clinical presentations, radiologic data (radiography, CT, and MRI), and laboratory reports were all subject to review.

RESULTS

All patients presented with pain and decreased range of motion (ROM) at the hip. Two of the six patients experienced pain in the anterolateral thigh and groin, with antalgic gait (anterior group). The other four complained of low back, buttock, and posterolateral thigh pain, accompanied by difficulty in standing and antalgic gait (posterior group). Edema within the GMe or effusion surrounding the muscle was regularly identified on MRIs. Calcific deposits were conspicuous in the gluteus medius tendon attachments to the lateral (anterior group) and superoposterior (posterior group) facets of the greater trochanter on radiography, CT, or MRI. Complete resolution of symptoms was uniformly achieved in 5-10 days with conservative management.

CONCLUSIONS

Acute CaT-GMe should be considered in any patient suffering lateral hip pain (with either groin or low back pain) and ROM limitation. Images of the hip characteristically show edema of the gluteus medius and calcifications lateral or superior to the greater trochanter.

Ultrasound-guided corticosteroid injections for treatment of greater trochanteric pain syndrome: greater trochanter bursa versus subgluteus medius bursa

OBJECTIVE

The purpose of this study was to evaluate the effectiveness of corticosteroid injections into the greater trochanteric bursa as opposed to the subgluteus medius bursa in patients with greater trochanteric pain syndrome.

MATERIALS AND METHODS

We retrospectively reviewed 183 injections (149 performed in women, 34 performed in men; age range 23-90 years; median, 53 years) performed for treatment of greater trochanteric pain syndrome. A 10-cm visual analog scale survey was used to assess pain level before the procedure and 14 days after the procedure. A 3-mL corticosteroid solution was injected into either the greater trochanteric bursa or the subgluteus medius bursa under direct ultrasound guidance. Procedure images were retrospectively reviewed to determine the site of injection. Diagnostic images obtained at the time of the procedure were also reviewed for findings of tendinopathy, bursitis, and enthesopathy. Statistical analysis of differences in pain reduction was performed, as was analysis for association between pain relief and demographic variables of age, sex, previous injections, and ultrasound findings.

RESULTS

Sixty-five injections met the inclusion criteria; 56 performed in women and nine performed in men (age range, 30-82 years; median, 53 years). Forty-one injections were into the greater trochanteric bursa and 24 into the subgluteus medius bursa. There was a statistically significant difference in pain reduction between greater trochanteric bursa and subgluteus medius bursa injections with a median pain reduction of 3 as opposed to 0 (p < 0.01). There was no statistically significant association between pain relief and demographic variables or ultrasound findings.

CONCLUSION

Corticosteroid injections into the greater trochanteric bursa may be more effective than injections into the subgluteus medius bursa for treatment of greater trochanteric pain syndrome.

Hip arthroscopy for extra-articular hip disease

The increasing popularity and success of hip arthroscopy has led to the development of related techniques for treating hip pathologies external to the joint proper. These minimally invasive endoscopic procedures serve in a diagnostic role to complement clinical evaluations and offer a therapeutic alternative to traditional open techniques. The indications for extra-articular hip endoscopy continue to expand. Recent literature describes applications for treating greater trochanteric pain syndrome, internal snapping hip, deep gluteal syndrome, and subspine impingement and for diagnosing and treating extra-articular sources of hip pain in patients who have undergone hip arthroplasty.

Trochanteric area pain, the result of a quartet of bursal inflammation

Bursitis is quite responsive to therapeutic intervention, once the afflicted area is accurately identified. This is especially notable for some hip complaints. Patients’ use of the term “hip” can relate to anything from the low back to groin to lateral thigh pain. Trochanteric area surface localization of “hip” pain may afford an opportunity for immediate cure. Effectiveness of therapeutic intervention is predicated upon injection of not one or two, but all four peri-trochanteric bursa with a depot (minimally water-soluble) corticosteroid. The term trochanteric bursitis suggests that the inflammation is more focal than what is clinically observed. While easier to express, perhaps it is time to refer to inflammation in this area, naming all four affected bursae.

MR imaging and ultrasound correlation of hip pathologic conditions

Magnetic resonance (MR) imaging has become the workhorse in the imaging evaluation of the painful or clinically abnormal hip. It provides an excellent anatomic overview and demonstration of the bony structures, articular surfaces, and surrounding soft tissues. Conversely, sonography can also demonstrate superficial intraarticular structures and the periarticular soft tissues, is quickly performed, allows dynamic evaluation of tendons and muscles, and can guide percutaneous procedures. These two modalities are complementary, and this article concentrates on the MR imaging-sonographic correlations of several entities about the hip.

Posterior hip pain in an athletic population: differential diagnosis and treatment options

Context:

Posterior hip pain is a relatively uncommon but increasingly recognized complaint in the orthopaedic community. Patient complaints and presentations are often vague or nonspecific, making diagnosis and subsequent treatment decisions difficult. The purposes of this article are to review the anatomy and pathophysiology related to posterior hip pain in the athletic patient population.

Evidence Acquisition:

Data were collected through a thorough review of the literature via a MEDLINE search of all relevant articles between 1980 and 2010.

Results:

Many patients who complain of posterior hip pain actually have pain referred from another part of the body—notably, the lumbar spine or sacroiliac joint. Treatment options for posterior hip pain are typically nonoperative; however, surgery is warranted in some cases.

Conclusions:

Recent advancements in the understanding of hip anatomy, pathophysiology, and treatment options have enabled physicians to better diagnosis athletic hip injuries and select patients for appropriate treatment.

The role of ultrasound in the assessment of post-operative complications following hip arthroplasty

Hip arthroplasty is one of the most commonly performed orthopedic procedures. Clinicians can be faced with the diagnostic dilemma of the patient presenting with a painful hip following arthroplasty and satisfactory post-operative radiographs. Identifying the cause of symptoms can be challenging and ultrasound is increasingly being utilized in the evaluation of potential soft tissue complications following hip surgery. In this article, we describe the common surgical approaches used during hip arthroplasty as this can influence the nature and location of subsequent complications. A review of the literature is presented along with the imaging appearances frequently encountered when imaging this patient population.

The diagnostic accuracy of magnetic resonance imaging and ultrasonography in gluteal tendon tears--a systematic review

Gluteal tendon tears are one of the many pathologies causing pain around the greater trochanter that are often labelled as trochanteric bursitis. We systematically reviewed the peer-reviewed literature to establish the accuracy of magnetic resonance imaging and ultrasonography in the diagnosis of gluteal tendon tears in patients with persistent lateral hip pain or Greater Trochanteric Pain Syndrome (GTPS). 7 studies met the inclusion criteria, comparing either imaging modality with a reference standard of surgical findings. Included studies were assessed for methodological quality using the QUADAS checklist. MRI had sensitivity of 33-100%, specificity of 92-100%, positive predictive value of 71-100% and negative predictive value of 50%. False-positives were common. High signal located superior to the trochanter had a stronger association with tears. Ultrasonography had a sensitivity of 79-100% and positive predictive value of 95-100%. The amount and quality of literature on the subject is limited and further well-designed studies are required to establish the optimum diagnostic strategy in this condition. Ultrasonography may prove to be the investigation of choice, despite requiring a skilled practitioner. The orthopaedic surgeon should liaise with an experienced musculoskeletal radiologist to best investigate and diagnose gluteal tendon tears in the clinical picture of GTPS.

Hip abductor muscle volume in women with lateral hip pain: a case-controlled study

Pathology of the hip abductor muscles and their associated tendons is implicated in the aetiology of lateral hip pain (LHP). Muscle atrophy is an important factor to consider in the diagnosis of this condition as it could result in reduced muscle volume and associated decreases in strength.

PURPOSE

(1) To estimate the volumes of the gluteus medius (GMed), gluteus minimus (GMin) and tensor fascia lata (TFL) muscles, and (2) to examine pathological changes of the soft tissues in the vicinity of the hip joint, in women with and without LHP.

METHODS

Twenty female participants (10 with LHP and 10 age-matched controls) underwent magnetic resonance imaging. Two radiologists reviewed the images for signs of pathological changes. Hip abductor muscle volumes were estimated using cross-sectional areas and Cavalieri's method. Differences in volume between sides, study groups and the three muscles were assessed.

RESULTS

The volume of GMed was the largest (292.5 ± 33.3 cm3), followed by GMin (82.1 ± 12.1 cm3), then TFL (49.7 ± 18.9 cm3). No differences were evident in the volumes of the hip abductor muscles in individuals with LHP when compared to age- and sex-matched controls (GMed, p = 0.30; GMin, p = 0.40; TFL, p = 0.90). Pathology of the soft tissues was not specific to the symptomatic hips.

CONCLUSIONS

Novel muscle volume data are presented for GMed, GMin and TFL in the context of LHP. Further research is needed to determine if symptom severity and duration have an impact on the extent of muscle atrophy in this population.

Imaging of the bursae

When assessing joints with various imaging modalities, it is important to focus on the extraarticular soft tissues that may clinically mimic joint pathology. One such extraarticular structure is the bursa. Bursitis can clinically be misdiagnosed as joint-, tendon- or muscle-related pain. Pathological processes are often a result of inflammation that is secondary to excessive local friction, infection, arthritides or direct trauma. It is therefore important to understand the anatomy and pathology of the common bursae in the appendicular skeleton. The purpose of this pictorial essay is to characterize the clinically relevant bursae in the appendicular skeleton using diagrams and corresponding multimodality images, focusing on normal anatomy and common pathological processes that affect them. The aim is to familiarize radiologists with the radiological features of bursitis.

Anatomic and radiographic evaluation of the hip

The hip is a challenging joint to study is deeply located in the pelvis and surrounding by a large group of muscles with complex tendinous attachments. Our knowledge has recently increased together with the advent of new surgical techniques but further research is needed to better understand hip biomechanics and the relevance of some of radiological findings. Although recent techniques such as MR show anatomy exquisitely is essential to start with pelvis plain radiography for a good evaluation of bone structures and pelvis alignment. During this chapter we will be give a short overview of pelvis normal structures and some key points of MR and MR arthrography technique, because more detailed description is done on every specific chapter.

Functional outcome after antegrade femoral nailing: a comparison of trochanteric fossa versus tip of greater trochanter entry point

OBJECTIVES

This study was performed to explore the relationship between entry point-related soft tissue damage in antegrade femoral nailing and the functional outcome in patients with a proximal third femoral shaft fracture.

DESIGN

Retrospective clinical trial.

SETTING

Level I university trauma center.

PATIENTS

Seventeen patients with a high femoral shaft fracture treated with an antegrade femoral nail joined the study.

INTERVENTION

Nine patients with an Unreamed Femoral Nail (UFN; Synthes, Bettlach, Switzerland) inserted at the trochanteric fossa and eight patients with a long Proximal Femoral Nail (PFN; Synthes) inserted at the tip of the greater trochanter.

MAIN OUTCOME MEASUREMENTS

Pain, gait, nerve, and muscle function along with endurance.

RESULTS

Five patients with a UFN had a positive Trendelenburg sign and a reinnervated superior gluteal nerve after initial injury of the nerve at operation. None of these findings occurred in the long PFN group (P = 0.01). Isokinetic measurements showed diminished abduction as well as external rotator function in the UFN group rather than in the long PFN group. Leg endurance was significantly lower in patients with a UFN.

CONCLUSIONS

Compared with the trochanteric fossa, femoral nailing through the greater trochanter tip may decrease the risk of damage to the superior gluteal nerve and intraoperative damage to the muscular apparatus of the hip region, resulting in some improved muscle function. Therefore, a lateral entry point may be a rational alternative for conventional nailing through the trochanteric fossa.

Intramedullary femoral nailing through the trochanteric fossa versus greater trochanter tip: a randomized controlled study with in-depth functional outcome results

PURPOSE

In a level 1 university trauma center, an explorative randomized controlled study was performed to compare soft tissue damage and functional outcome after antegrade femoral nailing through a trochanteric fossa (also known as piriform fossa) entry point to a greater trochanter entry point in patients with a femoral shaft fracture.

MATERIALS AND METHODS

Nineteen patients were enrolled and randomly assigned to two nail insertion groups; ten patients were treated with an Unreamed Femoral Nail(®) (UFN, Synthes(®), Solothurn, Switzerland) inserted at the trochanteric fossa and nine patients were treated with an Antegrade Femoral Nail(®) (AFN, Synthes(®), Solothurn, Switzerland) inserted at the tip of the greater trochanter. The main outcome measures were pain, gait, nerve and muscle function, along with endurance. Magnetic resonance imaging (MRI), electromyography (EMG), and Cybex isokinetic testings were performed at, respectively, 2 and 6 weeks and at a minimum of 12 months after surgery.

RESULTS

The MRI and EMG showed, in both groups, signs of iatrogenic abductor musculature lesions (four in the UFN group and four in the AFN group) and superior gluteal nerve injury (five in the UFN group and four in the AFN group). The isokinetic measurements and the patient-reported outcomes showed moderate reduction in abduction strength and endurance, as well as functional impairment with slight to moderate interference with daily life in both groups, with no appreciable differences between the groups.

CONCLUSIONS

Anatomical localization of the entry point seems to be important for per-operative soft tissue damage and subsequent functional impairment. However, the results of this study did not show appreciable differences between femoral nailing through the greater trochanter tip and nailing through the trochanteric fossa.

Partial-thickness tears of the gluteus medius: rationale and technique for trans-tendinous endoscopic repair

Tears in the gluteus medius and minimus tendons, often misdiagnosed as trochanteric bursitis, have recently emerged as an important cause of recalcitrant greater trochanter pain syndrome. Advances in endoscopic surgery of the hip have created opportunities to better evaluate and treat pathology in the peritrochanteric compartment. We reviewed the literature on trochanteric pain syndrome and gluteus medius tendon injuries. Existing techniques for endoscopic and open gluteus tendon repair and potential challenges in restoration of abductor function were analyzed. Partial-thickness undersurface tears of the gluteus medius were identified as a common pathologic entity. Although these tears are otherwise analogous to partial-thickness tears of the rotator cuff, the lack of arthroscopic access to the deep side of the gluteus medius tendon represents a unique technical challenge. To address the difficulty in visualizing and thus repairing undersurface tears of the gluteus medius, a novel endoscopic trans-tendinous repair technique was developed. The purposes of this article are to review the anatomy, pathology, and existing repair techniques of gluteus medius tendon tears and to describe the rationale and surgical steps for endoscopic trans-tendinous repair.

The hip abductors at MR imaging

Imaging of the hip abductors plays an increasing role for the evaluation of greater trochanteric pain in patients with and without total hip arthroplasty. This review article addresses the anatomy of the hip abductors and their intervening bursae. It highlights different possible imaging appearances such as tendinopathy or partial and full thickness tears of the gluteal tendons. Muscle atrophy or fatty degeneration of the gluteal muscles is an important reason for limping. Inflammatory diseases such as hydroxyapatite crystal deposition disease or spondylarthritis have to be considered. Knowledge of these different entities is important to achieve optimal treatment and outcomes.

Electromyographic analysis of the three subdivisions of gluteus medius during weight-bearing exercises

BACKGROUND

Gluteus medius (GM) dysfunction is associated with many musculoskeletal disorders. Rehabilitation exercises aimed at strengthening GM appear to improve lower limb kinematics and reduce pain. However, there is a lack of evidence to identify which exercises best activate GM. In particular, as GM consists of three distinct subdivisions, it is unclear if GM activation is consistent across these subdivisions during exercise. The aim of this study was to determine the activation of the anterior, middle and posterior subdivisions of GM during weight-bearing exercises.

METHODS

A single session, repeated-measures design. The activity of each GM subdivision was measured in 15 pain-free subjects using surface electromyography (sEMG) during three weight-bearing exercises; wall squat (WS), pelvic drop (PD) and wall press (WP). Muscle activity was expressed relative to maximum voluntary isometric contraction (MVIC). Differences in muscle activation were determined using one-way repeated measures ANOVA with post-hoc Bonferroni analysis.

RESULTS

The activation of each GM subdivision during the exercises was significantly different (interaction effect; p < 0.001). There were also significant main effects for muscle subdivision (p < 0.001) and for exercise (p < 0.001). The exercises were progressively more demanding from WS to PD to WP. The exercises caused significantly greater activation of the middle and posterior subdivisions than the anterior subdivision, with the WP significantly increasing the activation of the posterior subdivision (all p < 0.05).

DISCUSSION

Posterior GM displayed higher activation across all three exercises than both anterior and middle GM. The WP produced the highest %MVIC activation for all GM subdivisions, and this was most pronounced for posterior GM. Clinicians may use these results to effectively progress strengthening exercises for GM in the rehabilitation of lower extremity injuries.

Late repair of abductor avulsion after the transgluteal approach for hip arthroplasty

The abductor release sometimes does not heal after a transgluteal approach for hip arthroplasty. Factors influencing the success of subsequent repair are unclear. We used magnetic resonance imaging (MRI) to compare the condition of the gluteus medius with clinical outcome after late repair of abductor dehiscence in 12 total hip patients. Evaluation included a pain rating, gait evaluation, Trendelenburg test, strength grading, and Harris Hip Score. Most had both prerepair and postrepair MRI studies to assess the repair and to grade abductor muscle fatty degeneration. Two repairs without MRI were explored surgically. Although average pain, limp, and strength scores improved significantly, rerupture occurred in 4 subjects and fatty degeneration in the gluteus medius did not improve, even with intact repair. Nine patients were satisfied; 7 of these had an intact repair. Magnetic resonance imaging and operative observations suggest that chronic degeneration in the abductor mechanism is the major impediment to successful repair.

Sonographic evaluation of the abductor mechanism after total hip arthroplasty

OBJECTIVE

The purpose of this series was to determine the frequency of abductor mechanism avulsion by sonography after total hip arthroplasty with the Hardinge approach (J Bone Joint Surg Br 1982; 64:17-19) and its relationship to the presence of insufficiency of this musculature in the postoperative period.

METHODS

Thirty-four consecutive patients were prospectively accessed in the postoperative period of hip arthroplasty by the Trendelenburg test, hip sonography, and abductor muscle electromyography. In patients who were found to have clinical insufficiency of the abductor musculature, we also measured the femoral offset in the preoperative and postoperative radiographs. Hip sonography was performed by an experienced musculoskeletal radiologist blinded to the other tests, and the tendons of the gluteus medius and gluteus minimus were visualized on longitudinal and transverse sections with a 7- to 10-MHz linear transducer.

RESULTS

Eight patients presented clinical insufficiency of the abductor musculature as detected by the Trendelenburg test. Four of these 8 patients with abductor insufficiency presented tendinous avulsion detected by sonography. One of the 4 patients with abductor insufficiency and normal sonographic findings had a decrease in the femoral offset caused by the arthroplasty itself. Two patients presented electromyographic changes of the abductor musculature, with no tendinous avulsion detected by sonography and no abductor insufficiency.

CONCLUSIONS

We concluded that in patients undergoing total hip arthroplasty by the Hardinge approach in whom insufficiency of the abductor musculature develops, sonography is an interesting method of investigation because it identified the cause of this problem in most of our patients.

Kinesiology of the hip: a focus on muscular actions

The 21 muscles that cross the hip provide both triplanar movement and stability between the femur and acetabulum. The primary intent of this clinical commentary is to review and discuss the current understanding of the specific actions of the hip muscles. Analysis of their actions is based primarily on the spatial orientation of the muscles relative to the axes of rotation at the hip. The discussion of muscle actions is organized according to the 3 cardinal planes of motion. Actions are considered from both femoral-on-pelvic and pelvic-on-femoral perspectives, with particular attention to the role of coactivation of trunk muscles. Additional attention is paid to the biomechanical variables that alter the effectiveness, force, and torque of a given muscle action. The role of certain muscles in generating compression force at the hip is also presented. Throughout the commentary, the kinesiology of the muscles of the hip are considered primarily from normal but also pathological perspectives, supplemented with several clinically relevant scenarios. This overview should serve as a foundation for understanding the assessment and treatment of musculoskeletal impairments that involve not only the hip, but also the adjacent low back and knee regions.

Greater trochanteric pain syndrome: a review of anatomy, diagnosis and treatment

Greater trochanteric pain syndrome (GTPS) is a term used to describe chronic pain overlying the lateral aspect of the hip. This regional pain syndrome, once described as trochanteric bursitis, often mimics pain generated from other sources, including, but not limited to myofascial pain, degenerative joint disease, and spinal pathology. The incidence of greater trochanteric pain is reported to be approximately 1.8 patients per 1000 per year with the prevalence being higher in women, and patients with coexisting low back pain, osteoarthritis, iliotibial band tenderness, and obesity. Symptoms of GTPS consist of persistent pain in the lateral hip radiating along the lateral aspect of the thigh to the knee and occasionally below the knee and/or buttock. Physical examination reveals point tenderness in the posterolateral area of the greater trochanter. Most cases of GTPS are self-limited with conservative measures, such as physical therapy, weight loss, nonsteroidal antiinflammatory drugs and behavior modification, providing resolution of symptoms. Other treatment modalities include bursa or lateral hip injections performed with corticosteroid and local anesthetic. More invasive surgical interventions have anecdotally been reported to provide pain relief when conservative treatment modalities fail.