Gluteal Tendinopathy

Original Editor - Mariam Hashem

Lead Editors  

Introduction

Gluteal Tendinopathy (GT) is defined as moderate to sever disabling pain over the Greater Trochanter (lateral hip pain). It is often referred to as Greater Trochanter Pain Syndrome (GTPS) and was traditionally diagnosed as Trochanteric Bursitis, however, recent research defines non-inflammatory tendinopathy of the gluteus medius(GMed) and/or gluteus minimus (GMin) muscles to be the main source of lateral hip pain.

This condition affects both athletes (particularly runners) and less active people. One of four females over 50 years is likely to be affected by GT.

GT has significant impacts on the quality of life, with similar symptoms to those of hip OA. It interferes with sleep (side lying) and common weight bearing tasks.

Pathoanatomy/Pathomechanics

Tendon structure and loading capacity are influenced by mechanical loading which triggers physiological responses within the tendon. Under normal conditions, the tendon undergoes a cycle of balanced  catabolic and anabolic processes. Changes in loading type, intensity or frequency disrupt this harmony. Eccentric contractions in outer ranges (when the muscle is active and the tendon is lengthening simultaneously) represent the greatest form of  loading. Failure to adapt to loading, due to rapid increase in intensity and/or frequency with insufficient recovery time, results in a series of catabolic effects which in turn result in altering tenocyte behaviour, reducing load-bearing capacity and  predisposing tendons to injury at relatively low tensile loads. A combination of both tensile loading and compression are found to be more damaging than either alone.

GMed and GMin tendons are subjected to compression due to several factors:

1- Joint position: the ITB presents a compressive force on gluteal tendons that magnifies as the hip moves into further adduction. Birnbaum et al. reported a change from 4 to 106 N ITB compression as the angle of hip adduction increased from 0 to 40 degrees.  Adopting a constant or a repetitive hip adduction during static and dynamic tasks possibly contribute to the development of GT.

Examples of activities and positions:

• standing with one hip in adduction
• sitting with knees together crossed in adduction
• excessive lateral pelvic tilt or shift during dynamic single leg loading tasks.
• Running with a midline or cross-midline foot-ground contact pattern

ITB tension also exert loads on GMed and GMin tendons at higher degrees of flexion through the fascial confluence of the ITB with the gluteal fascia  .  These findings suggest that combining adduction and flexion, such as in sitting with the knee crossed or adducted, further increases the exerted ITB tension, thus worsens the condition.

2-Muscle Force: an imbalance in controlling frontal plane movement between the trochanteric abductors (GMed and GMin) and the ITB-tensioners (upper abducting portion of gluteus maximus (UGM), tensor fascia lata (TFL) and vastus lateralis (VL) was observed in patients with GT. Suggesting an an altered biomechanical force distribution and abnormal mechanical loading on gluteal tendons, however, further studies are needed to confirm this hypothesis.

3-Bony Factors: a biomechanical study using cadaveric modeling showed increased compressive force associated with reduced femoral neck angle. Another study related the severity of GT to lower femoral neck-shaft angle compared with pain-free subjects with hip OA. Lower neck-shaft angle is likely to contribute to greater offset (the difference between the width of the iliac wings and that of the greater trochanters). All these bony factors are suggested to influence ITB compression against gluteal tendons.

Females are more likely to develop GT. A study concluded that females, in general, tend to have a relatively smaller GMed insertion on the femur along with shorter moment arm resulting in reduced mechanical efficiency, particularly significant in those with smaller femoral neck shaft angle.

Clinical Presentation

Lateral hip pain caused by tendinopathy may be challenging to diagnose because of the long list of referred pain possibilities.

Pain is the main characteristic of GT, frequently insidious, gradually worsens with time and with different loads and tasks. The pain might be significant after a strong guarding contraction of the adductors during a slip or fall. It gets worse at nigh and sleeping on the affected side worsens the symptoms, affecting the quality of sleeping.

Assessing functional limitation and levels of discomfort is important. Patients usually report pain with single-loading tasks such as walking and stairs negotiation. Tasks that require active hip extension, such as  sit to stand,  are also accompanied with pain and stiffness. The latter is a mutual feature between GT and hip OA, however, patients with OA usually have difficulties manipulating shoes and socks (hip flexion) but this problem is not relevant with GT.

Diagnostic Procedures

A thorough hip examination is needed basically by obtaining patient's history to understand the nature of the symptoms and rule out Red Flags. Then, the assessor should go into PE with a hypothesis that to be confirmed with clinical tests. The following tests, although have weak diagnostic properties, are commonly used in MSK settings to confirm GT diagnosis:

• Ober's test
• Single stance assessment for 30 sec: recommended over Trendlenberg's test.
• Adduction/External Rotation with resistance
• FABER test: the hip ROM is not limited in GT.

Pain provocation and reproduction of symptoms by loading abductors are the aims of these test. Assessing active abduction in a position of hip adduction may be more useful.Further provocation could be elicited by testing the glueal muscles internal rotation function at a 90 degree hip flexion and maximal external rotation. The traditional Trendelenburg test was useful in diagnosing partial and complete abductor tendon tears at advanced stages of the pathology.

Pain on palpation of the structures over the greater trochanter is considered a cardinal sign in diagnosing Greater Trochanter Pain Syndrome. If the direct compression over this area failed to elicit pain then GT may be excluded and other conditions would be considered. The available literature has not yet provided a clear combination of diagnostic tests to confirm GT diagnosis. Further research is required to reach accurate and objective set of criteria and/or tests.

Assessing GT could be addressed from a different approach. Functional loading tests as prescribed by Cook and Purdam can be used to assess and track the tendon's response to therapy. Reduced pain on single leg standing and hopping indicates improved loading tolerance of the gluteal tendons. Longer standing time on one leg or  increased number of hops to onset of pain reflect improvement. Inadequate eccentric pelvic control in single leg loading tasks indicates a greater hip adduction moment arm and possible gluteal tendons compression. Video analysis of is suggested for athletes to observe pelvic tilt and femoral adduction in running and changing direction.

Imaging could be indicated, particularly if there was trauma involved, to exclude sever injury, fracture or other sinister pathology. Ultrasound is superior to MRI in diagnosing bursae, however, MRI is the  gold standard in distinguishing direct (soft tissue oedema, tendon thickening, intrasubstance signal abnormality and focal discontinuity or absence of tendon fibres) and indirect signs (fatty atrophy of the GMed and GMin muscles) of GT.

Differential Diagnosis

Hip OA

Avascular Necrosis

Femoral-acetabular Impingement (FAI)

Greater Trochanter Pain Syndrome

Trochanteric Bursitis

Management / Interventions

Tendon reloading principles are suggested in managing tendonpathies as a general. A randomized clinical trial by Mellor et al. compared the effectiveness of load management education plus exercise, corticosteroid injection and wait-and see approach. Education and exercise resulted in favorable outcomes in terms of pain and global improvement. 

Education

Educating patients on avoiding provocative movements that apply direct pressure on gluteal tendons for such as:

• Direct Pressure: by lying over the affected side
• Hip adduction: prolonged sitting with crossed knee, particularly on low seat, and prolonged weight shifting on one leg (handing on hip).
• Sustained postures and stretches
• Minimizing exposure to walking uphill, hopping, running and power walking in the short term.

This also includes training patients on using proper body mechanics when doing functional activities that require single-leg loading ,such as stairs negotiation, to be performed without excessive hip adduction and minimal trunk lean to minimize high external hip adduction moment.

Exercises

The exercise program suggested in Mellor et al. study utilized a combination of low load activation of abduction, pelvic control in frontal plane exercises and abductor loading in frontal plane.

To relief pain and activate abductors, isometric exercises were utilized from supine and standing positions using the belt as a resistance.

Bridging variations, squatting and lunges were used for functional Loading progressions and pelvic control training. It is important to integrate functional exercises at different positions to optimize the motor control.

To load abductors in frontal plane. subjects in exercise group performed different abduction exercises against spring resistance.

Motoring load appropriately is recommended by increasing load gradually without pain aggravation.

Steroid Injection

Corticosteriod injections provided analgesic effect,yet the pain doesn't resolve completely and and  often recurrent.  Corticosteriods exhibit non-inflammatory effect. on the other hand, GT is reported to be a degenerative condition rather than inflammatory.  The pain relieving effect following crticosteriods might interfer with the tendon capacity to respond appropriately to loading.

Surgical Intervention

Surgery is considered in persistent pain and failed conservative treatment. 90% long-term improvement was reported following GMed tendon repair in 72 patients. Endoscopic repairs provide an accelerated rehabilitaion and less invasive approach with reduced rates of post-operative infection, scar tissue formation and pain. Patients with larger tears are not suitable for endoscopic techniques.

Removal of trochanteric bursae and ITB release is utilized in patients without gluteal tears.  Studies report good to excellent short-medium term outcomes, however, most studies lacked control group and the rationale behind the mechanism of efficacy remains unclear.