What causes a swollen elbow and how should it be treated?

Swollen Elbow: Causes and Treatment

The most critical first step is obtaining plain radiographs immediately to differentiate between urgent conditions like septic arthritis, fractures, and dislocations versus less urgent causes like bursitis, tendinopathy, or inflammatory arthritis. 1, 2

Immediate Diagnostic Approach

Order standard elbow radiographs (AP, lateral, and oblique views) as first-line imaging to identify:

• Fractures and dislocations requiring urgent intervention 1
• Septic arthritis (joint effusion with systemic infection signs) 2
• Intra-articular loose bodies 2
• Heterotopic ossification 2
• Osteochondral lesions 3
• Soft tissue calcification 3

If septic arthritis is suspected based on systemic signs of infection and joint effusion, perform immediate arthrocentesis with culture before starting empiric antibiotics. 2 This is the most urgent distinction because delayed treatment of septic arthritis leads to joint destruction. Image-guided aspiration is essential when imaging cannot distinguish infected from noninfected fluid collections. 2

Common Causes by Anatomic Location

Posterior Elbow Swelling

Olecranon bursitis is the most common cause of posterior elbow swelling. 4 It can be septic or aseptic:

• Aseptic (chronic microtraumatic) bursitis should be managed conservatively with rest, ice, and activity modification—avoid routine aspiration due to infection risk. 5
• Septic bursitis requires aspiration with fluid analysis (cell count, Gram stain, culture) to guide antibiotic therapy 4
• Surgical excision is reserved only for refractory cases failing conservative treatment 5

Lateral Elbow Swelling

Lateral epicondylitis (tennis elbow) is a degenerative tendinopathy, not inflammatory "tendonitis": 3

• Presents with pain and tenderness over the lateral epicondyle, worsened by wrist extension 3
• Most patients (80%) recover within 3-6 months with relative rest, ice, and eccentric strengthening exercises. 3
• NSAIDs provide acute pain relief but cannot be recommended over other analgesics for long-term use 3
• Corticosteroid injections relieve pain but use with caution due to potential complications 3, 2

Medial Elbow Swelling

Medial epicondylitis (golfer's elbow) follows similar pathophysiology and treatment as lateral epicondylitis 3

Diffuse Joint Swelling

CT with IV contrast can differentiate cellulitis, myositis, tenosynovitis, abscess, and septic arthritis when soft tissue infection is suspected. 2

Treatment Algorithm

For Traumatic Swelling:

1. Obtain plain radiographs immediately 1, 2
2. If fracture/dislocation present: assess stability under fluoroscopy—gross instability requires surgical fixation, mild instability can be managed conservatively 1
3. If soft tissue injury: rest with activity modification, NSAIDs for pain, ice to reduce swelling, early range-of-motion exercises to prevent stiffness 1
4. Physical therapy with eccentric strengthening if tendinopathy suspected 1

For Non-Traumatic Swelling:

1. Rule out septic arthritis first—if suspected, perform immediate arthrocentesis 2
2. If olecranon bursitis: conservative management with relative rest, ice, activity modification 5
3. If chronic tendinopathy: relative rest, eccentric exercises, NSAIDs for acute pain 3
4. Avoid complete immobilization—use relative rest with activity modification instead 5

Advanced Imaging Indications

MRI without IV contrast is appropriate when radiographs are normal or nonspecific and you suspect: 3, 2

• Ligamentous injuries (UCL, lateral collateral complex) 2
• Tendinous pathology 2
• Osteochondral lesions 3
• Loose bodies (enhanced by joint fluid on T2-weighted images) 3

Dynamic ultrasound detects nerve dislocation and snapping pathology with 96% sensitivity when clinical suspicion remains high despite negative static imaging. 1

Critical Pitfalls to Avoid

• Never assume all elbow swelling is "tendonitis"—most chronic cases are degenerative tendinopathy ("tendinosus"), not inflammatory. 3 This distinction matters because anti-inflammatory treatment is not superior to other analgesics for degenerative conditions.
• Do not routinely aspirate chronic microtraumatic olecranon bursitis—this introduces infection risk. 5
• Do not miss septic arthritis—it requires urgent treatment to prevent joint destruction. 2 Any systemic signs of infection with joint effusion mandate immediate aspiration.
• Static imaging may miss dynamic pathology—if symptoms persist despite negative MRI, consider dynamic ultrasound or stress fluoroscopy 1
• Chronic swelling in adolescent athletes raises suspicion for osteochondral defects requiring surgical intervention 6

Surgical Referral Indications

Refer for surgical consultation when: 3, 5, 2

• Conservative treatment fails after 3-6 months 3
• Unstable fractures or dislocations 1, 2
• Refractory olecranon bursitis 5
• Confirmed septic arthritis requiring debridement 2