Bursitis

Populations and Risk Factors

• Occupational exposure: Repetitive joint loading or sustained pressure — roofers and carpet layers (prepatellar), students and desk workers (olecranon), overhead laborers (subacromial), long-distance runners (trochanteric, pes anserine)
• Age: Incidence increases after age 40 as tendons lose elasticity and bursal walls become less resilient to repetitive stress; subacromial bursitis peaks between ages 40–60
• Sex prevalence: Trochanteric bursitis is 2–4 times more common in women, likely related to wider pelvis geometry and greater Q-angle; pes anserine bursitis also shows female predominance
• Comorbidities: Rheumatoid arthritis (synovial inflammation extends to bursae), gout and pseudogout (crystal deposition within bursal fluid), diabetes (increased infection susceptibility)
• Prior trauma or surgery: Direct blow to a superficial bursa (olecranon, prepatellar) can cause acute hemorrhagic bursitis; post-surgical adhesions may irritate adjacent bursae
• Biomechanical factors: Lower crossed syndrome and hip abductor weakness increase trochanteric bursal loading; pes planus and genu valgum predispose to pes anserine bursitis
• Broken skin over a superficial bursa: Portal of entry for Staphylococcus aureus — the primary organism in septic bursitis

Causes and Pathophysiology

• Repetitive mechanical friction (most common cause): Tendons gliding repeatedly over bony prominences create shear stress on the bursal wall. The synovial lining responds with increased fluid production (effusion) to buffer the friction. When the rate of microtrauma exceeds the rate of repair, the bursal wall thickens and becomes chronically inflamed. This explains why bursitis is an overuse condition — the bursa is doing its job (reducing friction) but is overwhelmed by volume.
• Acute traumatic bursitis: A direct blow or fall onto a superficial bursa (olecranon, prepatellar) ruptures capillaries within the bursal wall, producing hemorrhagic effusion. The blood within the bursa triggers an inflammatory cascade, and if not reabsorbed, can organize into fibrous adhesions that thicken the wall permanently. This is why post-traumatic bursitis often becomes chronic even after the initial trauma resolves.
• Crystal deposition: In gout, monosodium urate crystals precipitate within the bursal fluid, activating neutrophils and producing an acute inflammatory response indistinguishable from septic bursitis on clinical examination alone. Calcium pyrophosphate crystals (pseudogout) produce a similar reaction. The clinical significance is that crystal-induced bursitis requires medical differentiation from infection before massage is appropriate.
• Septic bursitis: Bacteria (most commonly Staphylococcus aureus) enter through broken skin over a superficial bursa. The confined bursal space becomes an abscess-like environment — purulent fluid accumulates, the bursal wall becomes erythematous and edematous, and systemic signs (fever, malaise) may develop. Septic bursitis affects superficial bursae almost exclusively because deep bursae lack a direct cutaneous portal. This is why warmth, erythema, and broken skin over an olecranon or prepatellar bursa are red flags requiring medical referral.
• Autoimmune bursitis: In rheumatoid arthritis, the same pannus formation that erodes joint cartilage can involve the synovial lining of bursae. The bursa becomes chronically inflamed independent of mechanical stress. This explains why RA patients develop bursitis in multiple locations simultaneously, and why the bursitis recurs despite activity modification.
• Site-specific pathomechanics:
• Subacromial bursa: Lies between the supraspinatus tendon and the coracoacromial arch. During shoulder abduction, the supraspinatus passes beneath the acromion, compressing the bursa — maximal compression occurs between 70–130 degrees (the painful arc). Acromial morphology (Type III hooked acromion) reduces subacromial space and predisposes to impingement. The bursa inflames secondary to repetitive impingement, and its effusion further reduces subacromial space, creating a self-perpetuating cycle.
• Trochanteric bursa: Lies between the gluteus medius/minimus tendons and the greater trochanter. Hip abductor weakness or ITB tightness increases compressive loading over the trochanter with each gait cycle. The trochanteric bursa is now understood as part of greater trochanteric pain syndrome (GTPS), which frequently involves concurrent gluteal tendinopathy — pure isolated trochanteric bursitis is less common than previously thought.
• Olecranon bursa: Lies superficially over the olecranon process. Sustained pressure (leaning on elbows) or direct impact causes wall inflammation. Because the bursa is subcutaneous, swelling produces the characteristic visible "goose egg" that is diagnostically distinctive.
• Prepatellar bursa: Lies between the patella and the overlying skin. Prolonged kneeling (housemaid's knee) compresses the bursa against the patella. Like the olecranon, its superficial location makes swelling visually obvious and palpation straightforward.
• Pes anserine bursa: Lies between the conjoined tendon of sartorius, gracilis, and semitendinosus and the medial tibial plateau. Friction increases with genu valgum, pes planus, and tight hamstrings. Tenderness is 2–3 cm distal and medial to the joint line — this location distinguishes it from MCL tenderness (at the joint line) and medial meniscal pathology.

Signs and Symptoms

Superficial Bursitis (Olecranon, Prepatellar)

• Visible swelling: Localized, well-circumscribed "goose egg" directly over the bursa — this is the most distinctive finding and differentiates superficial bursitis from deeper joint effusion
• Point tenderness: Exquisitely tender on direct palpation of the bursa
• Warmth and erythema: Present in acute inflammatory or septic cases; erythema spreading beyond the bursa suggests cellulitis or sepsis
• ROM: Often relatively preserved because the bursa is not within the joint capsule; pain occurs primarily with direct compression (e.g., leaning on the elbow, kneeling)
• Function: Limited by pain with direct pressure rather than by movement restriction

Deep Bursitis (Subacromial, Trochanteric, Pes Anserine)

• Subacromial: Pain with overhead reaching and shoulder abduction; painful arc between 70–130 degrees; night pain when lying on the affected side; pain may refer to the lateral deltoid insertion (C5 dermatome overlap)
• Trochanteric: Lateral hip pain over the greater trochanter; worse with side-lying (direct compression), climbing stairs, and prolonged walking; tenderness does not radiate into the groin (distinguishing it from hip joint pathology)
• Pes anserine: Medial knee pain 2–3 cm below the joint line; worse with stair climbing and resisted knee flexion; common in overweight individuals with OA knee; may be mistaken for medial meniscal or MCL pathology
• Swelling: Not visible in deep bursitis because the bursa is covered by muscle and fascia; palpation may detect boggy fullness but not the discrete "goose egg" of superficial bursitis
• Pain pattern: Worsened by both active and passive motion that compresses or stretches the bursa — this differentiates bursitis from pure tendinopathy, which is typically painful primarily on resisted (active) contraction

Assessment Profile

Subjective Presentation

• Chief complaint: Localized pain and swelling over a joint — superficial bursitis patients often describe a visible lump (olecranon, prepatellar); deep bursitis patients describe activity-related pain in a specific location (lateral shoulder, lateral hip, medial knee) without visible swelling
• Pain quality: Dull, aching pain at rest that becomes sharp with direct pressure or specific movements; subacromial bursitis produces a catching or pinching sensation during the painful arc; trochanteric bursitis produces a deep lateral ache
• Onset: Usually insidious with gradual worsening over weeks; acute onset occurs with direct trauma (fall onto knee or elbow) or crystal deposition (gout flare produces rapid-onset severe pain)
• Aggravating factors: Direct pressure on the bursa (lying on the affected side for trochanteric; kneeling for prepatellar; leaning for olecranon); movements that compress the bursa (overhead reaching for subacromial; stair climbing for pes anserine and trochanteric)
• Easing factors: Avoiding direct pressure; ice application reduces acute inflammation; subacromial bursitis eases with the arm resting at the side (bursa not compressed)
• Red flags: Fever, spreading erythema, or broken skin over a superficial bursa with warmth → suspect septic bursitis; medical referral; do not treat

Observation

• Local inspection: Superficial bursae — visible, well-circumscribed swelling ("goose egg") directly over the olecranon or patella; deep bursae — no visible swelling; subacromial bursitis may show deltoid atrophy in chronic cases; trochanteric bursitis has no visible findings
• Posture: Subacromial — protective shoulder elevation and guarding with the arm held at the side; trochanteric — lateral trunk lean toward the affected side to unload the abductors; pes anserine — genu valgum or antalgic stance favoring the affected knee
• Gait: Trochanteric bursitis — Trendelenburg gait or compensatory lateral trunk lean during stance phase on the affected side; pes anserine bursitis — antalgic gait with shortened stance phase; olecranon and prepatellar bursitis do not affect gait

Palpation

• Tone: Subacromial — upper trapezius, levator scapulae, and rotator cuff hypertonicity from protective guarding. Trochanteric — gluteus medius/minimus guarding with TFL and ITB tightness. Pes anserine — medial hamstring and adductor hypertonicity. Olecranon/prepatellar — minimal surrounding muscle involvement.
• Tenderness: Precisely localized to the bursa — this point tenderness is the most diagnostically significant palpation finding. Subacromial: tenderness inferior to the anterolateral acromion, increased with the arm in extension. Trochanteric: tenderness directly over the greater trochanter. Pes anserine: tenderness 2-3 cm distal and medial to the medial joint line (NOT at the joint line — this differentiates from MCL). Olecranon: tenderness over the posterior olecranon process. Prepatellar: tenderness directly over the patella.
• Temperature: Warmth over the bursa in acute inflammation; marked warmth with erythema in septic bursitis; chronic bursitis may show no temperature change; always compare bilaterally — asymmetric warmth over a superficial bursa with broken skin or systemic symptoms warrants immediate referral
• Tissue quality: Superficial bursae — fluctuant, boggy swelling that is compressible and ballotable (distinguishes fluid-filled bursa from solid mass); chronic bursitis produces a thickened, fibrotic bursal wall that feels less fluctuant and more rubbery; deep bursae — no direct palpation of the bursa possible, but surrounding tissue shows fibrotic changes and reduced fascial mobility over time

Motion Assessment

• AROM: Pain during movements that compress or stretch the bursa — subacromial: painful arc 70–130 degrees abduction; trochanteric: pain with active hip abduction and external rotation; pes anserine: pain with resisted knee flexion and tibial internal rotation; olecranon: pain at end-range elbow flexion (compresses bursa); prepatellar: pain with full knee flexion (direct compression)
• PROM / end-feel: Pain reproduced at end-range passive motion that compresses the bursa; end-feel varies — acute bursitis shows a guarded or protective end-feel; chronic bursitis may show a normal end-feel with pain only at the extreme; subacromial bursitis pain increases with passive abduction plus internal rotation (Hawkins position); the key finding is that PROM reproduces pain in bursitis, whereas pure tendinopathy typically does not reproduce pain with passive motion alone
• Resisted testing: Variable — if the overlying tendon is involved (common in subacromial and trochanteric presentations), resisted testing reproduces pain; if the bursa alone is inflamed without tendon involvement, resisted testing may be pain-free or only mildly provocative; this variability is why bursitis cannot be diagnosed by RROM alone and why it is often confused with tendinopathy

Special Test Cluster

For trochanteric bursitis: Add resisted hip abduction and Ober's test to differentiate from gluteal tendinopathy and ITB tightness. For pes anserine bursitis: add valgus stress test and McMurray's to rule out MCL sprain and meniscal pathology.

Differential Assessment