Efficient radiological assessment of the internal snapping hip syndrome

Snapping Hip Syndrome: A Comprehensive Update

Purpose of review

This is a comprehensive literature review regarding the pathogenesis, diagnosis, and treatment of snapping hip syndrome (SHS). It covers the diverse etiology of the syndrome and management steps from conservative to more advanced surgical techniques.

Recent Findings

Recent advances in imaging modalities may help in diagnosing and treating SHS. Additionally, arthroscopic procedures can prove beneficial in treating recalcitrant cases of SHS and have recently gained popularity due to their non-invasive nature.

Summary

SHS presents as an audible snap due to anatomical structures in the medial thigh compartment and hip. While often asymptomatic, in some instances, the snap is associated with pain. Its etiology can be broadly classified between external SHS and internal SHS, which involve different structures but share similar management strategies. The etiology can be differentiated by imaging and physical exam maneuvers. Treatment is recommended for symptomatic SHS and begins conservatively with physical therapy, rest, and anti-inflammatory medications. Most cases resolve after 6-12 months of conservative management. However, arthroscopic procedures or open surgical management may be indicated for those with persistent pain and symptoms. Different surgical approaches are recommended when treating internal SHS vs. external SHS. Due to advancements in treatment options, symptomatic SHS commonly becomes asymptomatic following intervention.

Central compartment release versus lesser trochanter release of the iliopsoas tendon for the treatment of internal snapping hip: a comparative study

PURPOSE

To evaluate the results of 2 different techniques of endoscopic iliopsoas tendon release in the treatment of internal snapping hip syndrome.

METHODS

Between January 2008 and January 2012, a consecutive series of patients with the diagnosis of internal snapping hip syndrome were treated with endoscopic release of the iliopsoas tendon. The patients were divided into 2 groups according to the surgical technique used. Group 1 was treated with endoscopic iliopsoas tendon release at the lesser trochanter, and group 2 was treated with iliopsoas release from the central compartment. Hip arthroscopy of both the central and peripheral compartments was performed in both groups by the lateral approach. Associated injuries were identified and treated arthroscopically. The postoperative physical therapy protocol was the same for both groups. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were evaluated preoperatively and at last follow-up at a minimum of 24 months.

RESULTS

Twenty patients were included in the study: 6 in group 1 (4 male and 2 female patients; mean age, 35.6 years) and 14 in group 2 (5 male and 9 female patients; mean age, 32.7 years). Associated injuries were found and treated in 4 patients in group 1 and 10 patients in group 2. Every patient in both groups had an improvement in the WOMAC score. One patient in group 2 presented with recurrence of snapping that required surgical intervention. No complications were seen.

CONCLUSIONS

Both central compartment release and release at the lesser trochanter produced favorable results, based on WOMAC scores, for the treatment of internal snapping hip syndrome.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Medium-term and long-term outcomes of interventions for primary psoas tendinopathy

OBJECTIVE

To assess medium- and long-term outcomes of psoas tendinopathy to psoas tenotomy and image-guided steroid injections.

DESIGN

This is a 14-year retrospective case-control study to identify the efficacy of psoas tenotomy and image-guided steroid injections.

SETTING

This study was undertaken in a secondary care setting.

PATIENTS

Patients with confirmed psoas tendinopathy were followed up by postal questionnaire, which included a nonarthritic hip score (NAHS) and a study patient satisfaction questionnaire.

INTERVENTIONS

Patients underwent image-guided steroid injections. Depending on the analgesic or symptomatic relief, some patients proceeded to psoas tenotomy.

MAIN OUTCOME MEASURES

Response to steroid injection. Pain relief and symptomatic relief after the surgery.

RESULTS

Twenty-three patients were reviewed with a 70% follow-up over a time of 49 months for surgery (range, 13-144 months) and 77 months for injection (range, 14-160 months). Eight patients had a lasting response to injection and required no further intervention, and 15 patients proceeded to psoas tenotomy using a medial Ludloff approach. The average NAHS scores after the surgery and injection were 66.15 and 76.08, respectively. Ten patients reported pain relief after their tenotomy, and 5 patients reported no change in pain. All 8 patients, who only underwent injection, reported lasting pain relief.

CONCLUSIONS

Local steroid injections can provide long-term relief for patients presenting with psoas tendinopathy. For those patients with only temporary relief from injection, psoas tenotomy can provide good long-term pain relief.

Emerging intra-articular causes of groin pain in athletes

Groin pain remains one of the most poorly understood conditions in clinical sports medicine. It may be caused by either extra-articular or intra-articular conditions. While extra-articular causes have been extensively studied and reasonably understood, a number of elusive intra-articular causes are emerging, many of which were previously unknown and therefore undiagnosed, leading to premature ending of many competitive careers. This article makes an attempt to look at various, elusive intra-articular causes of groin pain in athletes. This article also analyses the currently available evidence on trends in diagnosis and treatment for these conditions.

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.

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.

Diagnóstico por imagem nas síndromes do estalido ou do ressalto

A síndrome do estalido ou do ressalto ocorre durante a movimentação de várias articulações e pode ser acompanhada de dor local e de crepitação ou de estalido audível. Nem sempre o estalido audível ou a crepitação articular à palpação têm significado patológico ou implicam necessidade de tratamento. Esta síndrome tem causas variadas intra-articulares e extra-articulares e os achados clínicos podem ser pouco precisos, com dificuldade para definir o melhor método de imagem que confirme o diagnóstico. O objetivo deste trabalho é discutir as causas mais comuns da síndrome do estalido em cada articulação e enfatizar a indicação e a limitação de cada um dos diferentes métodos diagnósticos em situações específicas da prática clínica.

Clinical examination and ultrasound of self-reported snapping hip syndrome in elite ballet dancers

BACKGROUND

Although snapping hip syndrome is commonly reported in ballet dancers, the prevalence, impact, and underlying mechanism of this condition have not been formally studied within a cohort of dancers.

PURPOSE

To determine the prevalence, associated factors, and mechanisms of snapping hip and to investigate self-reported snapping with physical and ultrasound examination.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A snapping hip questionnaire was completed by 87 unselected elite ballet dancers at 2 institutions. Twenty-six of the dancers (50 hips) who were able to voluntarily snap their hips were selected from this group for further physical examination by 2 clinicians to determine whether there was a palpable snap, and each underwent an ultrasound examination of his or her hips.

RESULTS

Ninety-one percent of dancers reported snapping hip, of which most (80%) had bilateral symptoms. Fifty-eight percent had pain associated with the snap, and 7% had taken time off dance because of this condition. Sixty percent of the dancers could voluntarily snap their hip. One or more of 3 dance movements elicited the snapping in 81%. The clinicians could palpate 46 of the 50 self-reported snapping hips. Ultrasound showed a snapping iliopsoas tendon in 59% of the hips and the iliotibial band snapping in 4%. In one third of cases, ultrasound was not helpful in identifying the cause of the snapping.

CONCLUSION

Snapping hip is extremely common in ballet dancers. Some dancers have significant pain, yet many are asymptomatic. Self-reported snapping is likely to be palpable by the clinician. Iliotibial band snapping is evident by physical examination and ultrasound. Iliopsoas snapping was most common and required ultrasonic confirmation.

Hip pain in adults: MR imaging appearance of common causes

To determine the exact origin of hip pain can be challenging. Symptoms apparently originating from the hip may arise from the pelvis, the sacroiliac joint, the lumbar spine, periarticular structures such as muscles and bursae, or from unexpected sites such as the abdominal wall, the genitourinary tract, or the retroperitoneal space. This article reviews the differential diagnosis of hip pain arising from the hip and surrounding structures and the role of different imaging methods with emphasis on magnetic resonance imaging where most recent advances have occurred.

Abnormalities in and Around the Hip: MR Imaging Versus Sonography

Sonography and MR imaging should be considered complementary rather than competing modalities. They demonstrate similar abnormalities of the soft tissues, but MR imaging is able to demonstrate intraosseous and articular abnormalities and offers a better anatomic overview because of its larger field of view, whereas sonography offers dynamic evaluation and can provide real-time guidance for percutaneous procedures. Both of these modalities have roles in the imaging evaluation of injuries in and around the hip.

Internal snapping hip syndrome: treatment by endoscopic release of the iliopsoas tendon

PURPOSE

The internal snapping hip syndrome is caused by slippage of the iliopsoas tendon over the iliopectineal eminence or the femoral head. Open surgical techniques have been successfully used to treat this condition. More recently, endoscopic techniques have become available to address this problem. The purpose of this study was to investigate an endoscopic technique for release of the iliopsoas tendon and its short-term results.

TYPE OF STUDY

Consecutive case series.

METHODS

Six patients (7 hips) with an average age of 38.5 years had an endoscopic release of the iliopsoas tendon for internal snapping hip syndrome. Hip arthroscopy was performed in every patient. Special inferior portals were used for psoas bursoscopy. The iliopsoas tendon was identified and released at the level of the lesser trochanter in all cases.

RESULTS

Intra-articular concomitant injuries were identified and treated in 4 cases. No snapping symptoms were present in any patient after surgery nor at the last follow-up at, on average, 21 months. Significant loss of flexion strength was present after surgery but had improved by 8 weeks.

CONCLUSIONS

In our hands, the endoscopic technique for iliopsoas tendon release was effective and reproducible and our results compare well with results of open procedures in the short term.

LEVEL OF EVIDENCE

Level IV.

Characterization of a linear streak artifact with pulse inversion tissue harmonics in musculoskeletal sonography

OBJECTIVE

To understand a linear artifact that projects deep to reflective structures that move rapidly while using tissue harmonic imaging with pulse inversion (PI) sonography. We hypothesize that this artifact is due to a cancellation error between firings in PI imaging, and it is, therefore, similar in generation to the twinkling artifact in color Doppler sonography. This artifact could be studied with the use of surfaces of different roughness to represent different rates of motion, in which roughness corresponds to spatial fluctuations in surface height. Given very slight variations in beam focusing as occurs with sonographic imaging arrays, these spatial fluctuations translate into temporal fluctuations in the received signal as would occur with tissue motion.

METHODS

We scanned 4 different sandpaper grits and a smooth surface through a water path using fundamental and PI mode, 1- and 2-pulse techniques, respectively. The sandpaper and the smooth surface were scanned through a water path at mechanical indices of 0.1 to 0.7. Four independent images were subtracted pairwise to remove nonfluctuating signals. These noise pixels were counted and analyzed.

RESULTS

Analysis of variance showed that the noise generated behind the different surfaces was highly significantly different. Two-tailed t tests generally showed significant differences in the quantity of noise between fundamental and harmonic imaging behind the roughest 3 grades of sandpaper. A multiple regression model showed significantly greater slopes for harmonic imaging for all grades of sandpaper and the smooth surface.

CONCLUSIONS

The noise and, by extension, the linear streak artifact in musculoskeletal imaging are dependent on the mechanical index and are functions of sandpaper roughness. This would be equivalent to a subtraction error between 2 firings due to soft tissue motion, and the artifact may be a way to identify rapid soft tissue motion in PI images.

MR imaging of sports-related hip disorders

Hip arthroscopy is being used increasingly for the diagnosis and treatment of hip disorders. MR imaging performed with appropriate technical considerations may aid not only in preoperative planning but in the appropriate selection of patients, which tends to lead to better postoperative results. Although the painful hip is imaged most commonly by radiography, MR imaging is considered the next imaging test of choice for evaluation of most common hip abnormalities in athletes, including labral injuries, ligament injuries, osteochondral injuries, fractures, bursitis, and musculotendinous injuries. MR arthrography can be a particularly useful technique for dedicated assessment of hip joint internal derangements.