Hip Bursitis MRI and Ultrasound Signs: Trochanteric Bursa

The two conditions frequently coexist but are anatomically distinct. Trochanteric bursitis refers to inflammation of one or more bursae between the greater trochanter and the overlying iliotibial band or gluteal tendons. Gluteal tendinopathy involves intrinsic tendon degeneration of the gluteus medius or minimus at their trochanteric insertions. On MRI, bursitis appears as T2 hyperintense fluid signal in the subgluteal space lateral and posterior to the trochanter. Tendinopathy manifests as intrasubstance T2 signal within the tendon footprint, with or without partial-thickness tearing, detectable on coronal fat-suppressed sequences. Distinguishing the two is clinically important because isolated bursitis responds well to corticosteroid injection, while gluteal tendinopathy is best managed with load-management physiotherapy and may require tendon repair or augmentation if a full-thickness tear is present.

Diagnostic ultrasound is useful for real-time dynamic assessment of the greater trochanteric region, detecting hypoechoic bursal fluid, tendon tears, and iliotibial band snapping. It is particularly valuable for guided injection procedures: ultrasound-directed corticosteroid injection into the trochanteric bursa is significantly more accurate than landmark-based injection and improves short-term pain outcomes. Ultrasound also allows sequential imaging to monitor treatment response and guides percutaneous needling (barbotage) of calcific deposits within the gluteal tendons. For equivocal cases where the diagnosis is unclear or tendon integrity needs precise characterization, MRI remains the definitive investigation.

MRI can show trochanteric or subgluteal bursal fluid, peritrochanteric edema, gluteal tendon disease, and marrow reaction near the greater trochanter. These findings support the imaging impression, but a clinician still needs to match them with the pain location, examination, and other possible causes of lateral hip pain.

X-ray and CT can support the workup by showing hip osteoarthritis, fracture, enthesophytes, calcific deposits, or hardware-related causes of lateral hip pain, but they usually cannot confirm bursitis itself. MRI and ultrasound are better for seeing trochanteric bursal fluid, gluteus medius or minimus tendon disease, and peritrochanteric edema.

CT is better when the main question is cortical fracture, hardware position, post-operative bone detail, or mineralized calcification around the greater trochanter. MRI is usually better for bursitis, gluteal tendons, marrow edema, and other soft-tissue causes. CT findings should not be used alone to confirm or exclude symptomatic bursitis.

A clinician should confirm that the pain is lateral and reproducible over the greater trochanter, check hip abductor strength and gait, review gluteus medius and minimus tendons, and consider referred lumbar, intra-articular hip, inflammatory, infectious, or post-surgical causes when the story does not fit simple greater trochanteric pain syndrome.

AI can point out visible imaging patterns, but it cannot prove which structure is the true pain generator, diagnose infection or systemic inflammatory disease, decide whether an injection is appropriate, or replace a radiologist or orthopedic clinician. Treat the output as an informational second look, not a diagnosis.

Several biomechanical and systemic factors increase recurrence risk. Leg length discrepancy alters pelvic obliquity and elevates iliotibial band tension over the trochanter. Reduced hip abductor strength leads to excessive contralateral pelvic drop during gait (Trendelenburg pattern), increasing compressive and tensile loads on the trochanteric region. Wide pelvis anatomy, particularly in women, raises the Q-angle and iliotibial band traction. Systemic factors such as rheumatoid arthritis, calcium pyrophosphate deposition, and prior hip surgery or hardware also predispose to bursal inflammation. Effective long-term management requires identifying and correcting the underlying mechanical contributors rather than relying on repeated corticosteroid injections, which may paradoxically weaken adjacent tendon tissue with multiple administrations.