Elbow X-Ray — Findings & How to Read It

What Is This X-Ray?

Abnormal Findings in This X-Ray

1. Distal Humerus Fracture (Supracondylar Pattern)

2. Posterior Fat Pad Sign (Lateral View)

"Any posterior fat pad is pathological and indicates the presence of joint effusion. In the setting of trauma, patients with a radiological posterior fat pad sign are assumed to have an intra-articular skeletal injury." — Rosen's Emergency Medicine, 10th Ed.

3. Anterior Humeral Line Violation (Lateral View)

4. Significant Bony Displacement/Comminution

How to Systematically Read an Elbow X-Ray (Standard Method)

Step 1 — Confirm Two Views

Step 2 — AP View: Draw Baumann's Angle

Fig: (A) Normal AHL bisects middle third of capitellum. (B) Extension supracondylar fracture — line passes anterior to capitellum. — Rosen's Emergency Medicine

Step 3 — Lateral View: Draw the Anterior Humeral Line (AHL)

• Draw a line down the anterior cortex of the humerus
• It should bisect the middle third of the capitellum
• If the line passes through the anterior third or misses the capitellum → extension-type supracondylar fracture

Step 4 — Lateral View: Check Radiocapitellar Line

Step 5 — Lateral View: Fat Pad Signs

Fig: Lateral radiograph showing both anterior fat pad (sail sign) and posterior fat pad — both indicate haemarthrosis. — Tintinalli's Emergency Medicine

Step 6 — CRITOE Mnemonic (Paediatric Elbow Ossification Centers)

Step 7 — Look for Specific Fracture Lines

Textbook Reference: Gartland Classification of Supracondylar Fractures

Summary of This X-Ray

Neglected Posterior Elbow Dislocation (3 Months Old)

Correcting the Previous Diagnosis

X-Ray Findings in This Case (Explained)

Fig: Acute posterior elbow dislocation — Tintinalli's Emergency Medicine

On the AP View (left image of your X-ray):

On the Lateral View (right image):

Definition & Classification

"Untreated traumatic posterior dislocation of the elbow joint, 3 weeks or older, is defined as 'neglected posterior dislocation of the elbow'. Approximately 90% are of posterolateral type." — Pal et al., J Clin Orthop Trauma, 2021 [PMID: 33996454]

Pathological Changes at 3 Months (Why It's Difficult)

Radiological Checklist for Neglected Elbow Dislocation

1. ✅ Direction of dislocation — posterior (olecranon/radius behind humerus)
2. ✅ Radiocapitellar line disrupted — radial head not pointing to capitellum
3. ✅ Anterior humeral line disrupted — capitellum uncovered
4. ✅ Heterotopic ossification — peri-articular new bone (amount and location)
5. ✅ Associated fractures — coronoid process? radial head? medial epicondyle avulsion?
6. ✅ Degree of articular damage — joint space narrowing, subchondral changes
7. ✅ Bony remodelling — pseudoarthrosis or false joint formation?

Treatment of Neglected Posterior Elbow Dislocation (3 Months)

"Goal of surgical treatment is to achieve a painless, stable and mobile elbow with a congruent joint space." — Pal et al., 2021

Why Closed Reduction Fails at 3 Months

Surgical Treatment: Open Reduction (ORIF)

1. Ulnar nerve identification and protection (compulsory)
2. Release of posterior capsule and contractures
3. Excision of heterotopic bone / fibrous tissue blocking reduction
4. Release of medial and lateral collateral ligaments as needed (then repair)
5. Reduction of the joint under direct vision
6. Stabilisation — usually with hinged external fixator or K-wires if unstable
7. Collateral ligament repair/reconstruction

"23 patients treated via posterior approach surgery — average time onset to surgery 7.83 months. Mean DASH score 15.32, MEPI score 90 (satisfactory functional outcomes)." — Hadinoto et al., Malaysian Orthop J, 2026 [PMID: 42078978]

Post-operative Protocol

• Hinged elbow brace with early active motion
• Aggressive physiotherapy — crucial for regaining range of motion
• NSAIDs / low-dose radiation to prevent recurrence of heterotopic ossification

Complications

Summary Card