2011. 12. 4.

Gluteus Minimus Tear and Trochanteric Bursitis



MRI Web Clinic - May 2004
Gluteus Minimus Tear and Trochanteric Bursitis
by Michael E. Stadnick, M.D.
Clinical History: 70 year-old female with chronic left hip pain. Coronal T1-weighted (A), Coronal STIR (B), and Axial T2-weighted (C) images are provided. What are the findings? What is your diagnosis?
A
B
C
Findings
A

T1-weighted coronal image of the pelvis demonstrates abnormal intermediate signal lateral to the left greater trochanter (arrow).
B

STIR coronal image demonstrates increased signal lateral to the left greater trochanter (arrow).
C

T2-weighted axial image through the left hip demonstrates an irregular and attenuated gluteus minimus tendon (arrow), which is displaced from its site of insertion at the anterior facet of the greater trochanter (arrowhead).

Fluid signal is noted lateral to the lateral facet of the trochanter within the trochanteric bursa (short arrow).
Diagnosis
Gluteus minimus tear of the left hip with associated trochanteric bursitis.
Discussion
Lateral hip pain is frequently a challenging diagnostic and therapeutic problem. In the past, the presentation of chronic lateral hip pain with tenderness over the greater trochanter was attributed to trochanteric bursitis. This symptom complex, called greater trochanteric pain syndrome (GTPS),1 can mimic other serious causes of hip pain, including avascular necrosis, stress fracture, and arthritis of the hip. In addition, lateral hip pain is often not limited to the greater trochanter region but may extend into the buttock and groin, further complicating the clinical presentation. Abductor tendon (gluteus minimus and gluteus medius) tears are becoming increasingly recognized as a frequent cause of pain at the hip. In fact, tears of the abductor tendons, instead of trochanteric bursitis, are likely the most common cause of GTPS.2

The gluteus minimus and gluteus medius tendons insert on the greater trochanter and make up the "rotator cuff of the hip".3 The greater trochanter surface is composed of four distinct facets: anterior, lateral, posterior, and superoposterior (Figs D,E).

The gluteus minimus attaches to the anterior facet, and the gluteus medius inserts on the superoposterior and lateral facets (Figs D,E,F).

Although variable, three bursae are commonly encountered:
trochanteric, subgluteus medius, and subgluteus minimus (Fig D).4
D

Frontal and lateral views of the anatomy at the greater trochanter. The four facets of the greater trochanter are: anterior (A), lateral (L), posterior (P), and superoposterior (SP). The gluteus minimus tendon (Gmn) inserts on the anterior (A) facet and the gluteus medius (Gme) inserts on the superoposterior (SP) and lateral (L) facets. Three commonly encountered bursae are: trochanteric (TB), subgluteus minimus (SGmn), and subgluteus medius (SGMe).
E

T1-weighted coronal image demonstrates the level of axial images A and B.
Proton density-weighted axial image (A) demonstrates the normal appearance of the gluteus minimus tendon (arrow) inserting on the anterior facet of the greater trochanter.
Proton density-weighted axial image (B) at a higher level, demonstrates the gluteus medius tendon (arrow) inserting on the superoposterior facet.
F

T1-weighted coronal images through the anterior (top) and posterior (bottom) portions of the greater trochanter demonstrate the insertion of the gluteus minimus tendon (arrow) at the anterior facet and the gluteus medius tendon (arrowhead) at the superoposterior facet. The gluteus minimus (Gmn) and gluteus medius (Gme) muscles are labeled.
In a large majority of patients, trochanteric bursitis or distension will accompany an abductor tendon tear. The frequent coexistence of trochanteric bursitis and abductor tendinopathy has led some authors to suggest that bursitis may in fact be a result of the underlying tendinopathy.2 One should therefore be careful in providing an isolated diagnosis of trochanteric bursitis without first closely inspecting the abductor tendons.

The MRI appearance of tendinosis and tear of the abductor tendons of the hip is the same as in other locations and includes alterations in tendon signal and caliber. Partial thickness and complete tears of the gluteus minimus or medius tendons are visible with MRI (Fig G). Muscle atrophy is frequent with chronic large tears. If a larger field of view is utilized to incorporate both hips, tendon visualization is often limited and secondary signs become critical in detecting abductor tendon tears. The most frequently encountered secondary sign is a greater than 1 cm in diameter localized area of high signal superior to the greater trochanter (Fig H). A thin layer of increased signal intensity enveloping the lateral and superior aspect of the greater trochanter also correlates with the presence of abductor tendon tear. Tendon elongation of the gluteus medius, likely representing muscle atrophy, is an additional finding seen in slightly greater than 50% of patients with tendon tears (Fig I).5
G

Proton density-weighted axial images from the same patient. The image on the top demonstrates the normal appearance of the gluteus minimus (Gmn) and gluteus medius (Gme) tendons.
The image on the bottom demonstrates absence of the tendons at the anterior facet (arrowheads) and lateral facet (short arrows) of the greater trochanter, indicating tears of both the gluteus minimus and gluteus medius tendons. The trochanteric bursa (TB) is distended compatible with associated bursitis.
H

Secondary sign of tendon tear. A STIR coronal image demonstrates localized fluid signal (arrow) superior to the superoposterior facet, within the subgluteus medius bursa.
I

Secondary sign of tendon tear. T1-weighted coronal image of the pelvis demonstrates a lax and elongated appearing gluteus medius tendon (oval). Gluteus medius (Gme) and gluteus minimus (Gmn) muscles are labeled.
Early descriptions of abductor tendon tears at the hip emphasized involvement of the gluteus medius tendon as being most common.6 However, subsequent papers have revealed a roughly equal frequency of involvement of the gluteus minimus and medius tendons.5 As expected, the injury shares a similar age distribution with trochanteric bursitis, being most common between the fourth and sixth decades. Non-surgical management, which includes corticosteroid injections into the trochanteric bursa, is typically unsuccessful at providing long-term relief, and surgery may be necessary to repair a torn abductor tendon.6
Conclusion
Tendinopathy of the abductor tendons of the hip is becoming increasingly recognized as a significant cause of lateral hip pain. Trochanteric bursitis, rather than being the primary abnormality, is often a manifestation of underlying abductor tendon pathology. The presence of trochanteric bursitis should thus prompt a careful evaluation of the abductor tendons. MRI allows accurate detection of tears of the abductor tendons and allows effective treatment planning in such cases.


Calcific tendinitis

References
1 Shbeeb MI, Matteson EL. Trochanteric bursitis (greater trochanter pain syndrome). Mayo Clin Proc. 1996 Jun;71(6):565-9.

2 Kingzett -Taylor A, Tirman PF, Feller J, McGann W, Prieto V, Wischer T, Cameron JA, Cvitanic O, Genant HK. Tendinosis and tears of the gluteus medius and minimus muscles as a cause of hip pain: MR imaging findings. AJR 1999;173:1123-1126.

3 Bunker TD, Esler CN, Leach WJ. Rotator-cuff tear of the hip. J Bone Joint Surg Br 1997;79:618-20.

4 Pfirrmann CWA, Chung CB, Theumann NH, Trudell DJ, Resnick D. 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. Radiology 2001; 221:469-477.

5 Cvitanic O, Henzie G, Skezas N, Lyons J, Minter J. MRI Diagnosis of Tears of the Hip Abductor Tendons (Gluteus Medius and Gluteus Minimus). AJR 2004;182:137-143

6 Kagan A 2nd. Rotator cuff tears of the hips. Clin Orthop 1999; Nov;(368):135-140.