Trochanteric Bursitis

Greater trochanteric pain syndrome (GTPS) is the modern term for lateral hip pain arising around the greater trochanter. Trochanteric bursitis, gluteal tendinopathy and iliotibial band (ITB) friction syndrome are sub-diagnoses under this umbrella. "Trochanteric bursitis" is historically entrenched but anatomically imprecise, so do not use it as a catch-all in the exam: say GTPS, then specify the underlying pathology.

Why it matters. GTPS is one of the most common musculoskeletal complaints, with an estimated incidence of 1.8 per 1000 per year, and the third most frequent reason for a primary care musculoskeletal consultation after low back pain and knee pain. It is frequently misdiagnosed as hip osteoarthritis or lumbar radiculopathy, which delays treatment or sends it the wrong way. Distinguishing GTPS from lumbar spine referral and hip OA is a classic exam differential.

Who. Between 10 and 25 percent of adults will experience lateral hip pain. The female-to-male ratio is approximately 4:1, the peak age is 40-60 years, and perimenopausal women are at highest risk. It is associated with obesity, lumbar spine pathology, hip OA and total hip replacement, and up to one-third of cases are bilateral.

The footprint. The "rotator cuff of the hip" analogy is only useful if you know the footprint, which is examinable anatomy: it explains where tears occur and where injections should, and should not, go. The greater trochanter has four facets (Pfirrmann/Robertson anatomy):

• Anterior facet - insertion of gluteus minimus
• Lateral facet - the main insertion of gluteus medius
• Superoposterior facet - the second insertion of gluteus medius
• Posterior facet - the "bald" facet, with no tendon insertion, covered by the trochanteric (subgluteus maximus) bursa

The bursae. Three main bursae lie around the greater trochanter. The subgluteus maximus bursa, the trochanteric bursa proper, is the largest and the one most commonly inflamed in clinical "trochanteric bursitis"; it overlies the trochanter, between gluteus maximus and the greater trochanter and gluteus medius tendon. The subgluteus medius bursa lies deep to the gluteus medius tendon at its insertion, and the subgluteus minimus bursa deep to the gluteus minimus tendon. The ITB overlies the greater trochanter, and friction there can contribute to pain.

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The hip's rotator cuff. Gluteus medius is the primary hip abductor and pelvic stabiliser during gait, and its insertion on the greater trochanter is analogous to the supraspinatus insertion on the greater tuberosity. Like rotator cuff disease, an overloaded tendinopathy progresses from reactive to degenerative, and partial-thickness tears may progress to full-thickness tears. The tear sequence mirrors the cuff as well: anterior gluteus minimus and lateral gluteus medius fail first, analogous to supraspinatus.

Where the tears are. Gluteus minimus tears are anterior. Gluteus medius tears, the commonest, are at the lateral and superoposterior facets, directly under the point of maximal tenderness.

Tendon more often than bursa. Modern imaging with MRI and ultrasound shows that true bursitis accounts for only a minority of cases. The majority of patients have gluteus medius or minimus tendinopathy, with or without bursal inflammation, and the bursae may be secondarily inflamed by adjacent tendon pathology, mechanical friction or direct pressure. The distinction changes management: tendinopathy requires progressive loading, the evidence-based treatment, not just anti-inflammatory measures, and corticosteroid may give temporary relief but risks further tendon degradation.

GTPS is divided by the structure at fault, and the subtype guides management: tendinopathy needs loading, bursitis needs anti-inflammatory measures, and ITB syndrome needs stretching and biomechanical correction.

Mixed disease. Approximately 15-25 percent have tendinopathy with secondary bursitis, and show features of both tendon and bursal pathology.

Severity. Grading guides escalation. Mild cases may resolve with self-management, while severe cases need imaging and specialist input to rule out tendon tears.

History. The pain is over the lateral aspect of the hip and may radiate to the lateral thigh, but not below the knee. Night pain is common, with difficulty sleeping on the affected side. Onset is insidious in tendinopathy and acute in bursitis. The aggravating activities are characteristic:

• Lying on the affected side
• Climbing stairs
• Rising from a chair
• Crossing the legs

Function suffers on stairs, with prolonged walking and in side-sleeping. Record any previous treatment (NSAIDs, physiotherapy, injections) with its response and how long it lasted.

Examination. Watch the gait for a Trendelenburg pattern and pelvic tilt, and look for gluteal wasting. Point tenderness over the greater trochanter, most commonly its posterolateral aspect, is the hallmark but is non-specific. Hip range of motion is usually full, unlike hip OA, which restricts internal rotation. The provocative tests:

• Single-leg stance for 30 seconds - the best provocative test; pain reproduced within 30 seconds is highly sensitive for GTPS
• Resisted abduction in side-lying at 30 degrees - provokes gluteal tendon pain at the trochanter, pointing to gluteal tendinopathy
• Trendelenburg sign - the pelvis drops on the contralateral side during single-leg stance, abductor weakness that points to tendinopathy
• Neurological screen - lumbar spine, femoral nerve stretch and sensation over the lateral thigh, to exclude radiculopathy

Differential diagnosis. The cause of lateral hip pain is not always the trochanter. L4-L5 radiculopathy or facet pain may refer to the lateral hip, and radiculopathy also brings reflex changes, positive neural tension signs and tenderness over the lumbar paraspinals rather than the trochanter. Hip OA may present with lateral hip pain, not just groin pain, femoroacetabular impingement or labral tears may refer laterally, and lateral knee OA or ITB syndrome may present similarly.

The diagnosis of GTPS is primarily clinical, and imaging is not required for typical presentations. When it is used, radiographs exclude other pathology and MRI defines the lesion.

Radiographs. An AP pelvis and a lateral hip (cross-table lateral or frog lateral). They are often normal in isolated GTPS, and their primary role is excluding other pathology such as hip OA, fracture and tumour. Look for:

• Greater trochanteric enthesophytes and calcific tendinopathy
• Hip OA (joint space narrowing)
• Femoral neck stress fracture, which may be normal early
• Pelvic pathology

MRI. The gold standard for differentiating bursitis from tendinopathy and for grading tendon tears. Bursitis shows fluid distension of the subgluteal bursae (high T2 signal) and peritrochanteric oedema. Tendinopathy shows increased T2 signal within the gluteus medius and minimus tendons, tendon thickening, partial or full-thickness tears and tendon retraction. The same scan assesses the hip joint for concurrent labral tears, chondral damage and femoroacetabular impingement. Request MRI when:

1. Symptoms are refractory to conservative management, after a minimum of 6-8 weeks (the conservative protocol's formal review falls at 12 weeks)
2. There is significant abductor weakness or a Trendelenburg sign, suggesting a gluteal tendon tear
3. There is diagnostic uncertainty: possible hip OA, stress fracture or lumbar pathology
4. Surgical planning is being considered

Ultrasound. The alternative, and the dynamic one: it assesses the peritrochanteric structures in motion. It shows bursal fluid, tendon thickening and calcifications, assesses ITB snapping in real time, and guides injection, so diagnostic and therapeutic injection can be done at one sitting under direct visualisation. It is operator-dependent and cannot assess deep structures or the hip joint as well as MRI.

Management escalates from conservative care to image-guided injection to surgery.

The most clinically significant "complication" of GTPS is incorrect diagnosis. Patients with lumbar radiculopathy, hip OA, femoral neck stress fractures or femoroacetabular impingement may present with lateral hip pain and be inappropriately treated for bursitis.

Prognostic factors. The best prognosis belongs to isolated bursitis, an acute presentation, compliance with physiotherapy, a normal BMI and no associated lumbar or hip pathology. Chronic symptoms (over 6 months), gluteal tendon tears, obesity, concurrent lumbar spine pathology, previous hip surgery (especially lateral approach THR) and poor compliance with rehabilitation carry a poor prognosis. Early and accurate diagnosis with appropriate rehabilitation gives the best outcomes.