Radial Head Dislocations

Based on the direction of the Radial Head dislocation (and Ulna apex).

• Type I (Anterior): Most common in kids (70%). Anterior head dislocation. Anterior ulna apex.
• Type II (Posterior): Most common in adults (80%). Posterior head dislocation. Posterior ulna apex. Associated with radial head fractures.
• Type III (Lateral): Lateral head dislocation. Lateral ulna apex. (Rare, associated with PIN palsy).
• Type IV: Fracture of both Radius and Ulna with dislocation.

• Congenital (rare):
  • Hereditary: Associated with syndromes (Nail-Patella, Klippel-Feil, Ehler-Danlos).
  • Bilateral: 60% of cases.
  • Radiology:
    • Dome shaped radial head (convex).
    • Hypoplastic capitellum.
    • Short ulna (Negative ulnar variance).
    • Anterior dislocation (usually).
  • Treatment: Leave it alone! Reducing a congenital head will cause massive stiffness and pain.
• Traumatic (Acquired):
  • Unilateral.
  • Concave head (normal).
  • Normal capitellum.
  • History of trauma (or missed trauma).
  • Plastic Deformation: In kids, the head may be out because the ulna is bowed (plastic deformation). The ulna must be straightened (Osteoclasis) to allow the head to reduce.

Classification of Radial Head Fractures (often associated with dislocation):

• Type I: Non-displaced (less than 2mm). Stiff but stable. Treat non-operatively.
• Type II: Displaced (greater than 2mm) but reconstructible. Treat with ORIF (Lag screw or Plate).
• Type III: Comminuted, not reconstructible. Treat with Excision (if MCL intact) or Replacement (if MCL torn).

Pulled Elbow (Subluxation):

• Reduction:
  1. Hyperpronation: Hold elbow at 90. Firmly pronate wrist. Usually clicks. High success rate.
  2. Supination-Flexion: Supinate wrist, then flex elbow.
• Post-Reduction: Child should use arm within 10-15 mins. No cast needed.

Principle: "Reduce the Ulna, and the Head will follow."

• Paediatric (Type I):
  • Reduction: Longitudinal traction with the elbow in extension (to disengage the head) followed by flexion.
  • Immobilization: Long arm cast in 100-110 degrees of flexion and fully supinated (to relax Biceps and tighten IOM).
  • Follow-up: Weekly X-rays. If the ulna angulates, the head will sublux.
• Adult:
  • ORIF Ulna (Plate): Anatomical reduction is mandatory. The ulna length must be restored perfectly.
  • Head Stability: After plating the ulna, assess the radial head.
    • Stable: No further action. Start early motion.
    • Unstable: Check for interposed annular ligament. Repair LCL?
  • This is a posterior dislocation variant.
  • Sequence:
    1. Fix Coronoid (or suture capsule).
    2. Fix/Replace Radial Head.
    3. Repair LCL.
    4. Protect in hinged brace.
  • Pearl: Do NOT repair the MCL unless instability persists after lateral reconstruction.

Always check stability in pronation (most stable).

Problem: Ulnar malunion leads to permanent dislocation.

• Treatment: Ulnar Osteotomy (Lengthening + Angulation) + Open Reduction of Radial Head + Reconstruction of Annular Ligament (Triceps fascia or Palmaris).
• Timing: Best results if done before age 4. After age 10, reconstruction has poor outcomes (stiffness).

Congenital Syndromes:

• Nail-Patella Syndrome: Hypoplastic nails, absent patellae, radial head dislocations.
• Klippel-Feil: Cervical fusion, low hairline, radial head issues.
• Cornelia de Lange: Multiple anomalies.
• Ehlers-Danlos: Ligamentous laxity leading to habitual dislocation.

Indications: Irreducible acute dislocation or Chronic reconstruction.

• Approach: Kocher (Interval: Anconeus/ECU) or Kaplan (EDC/ECRB).
• Technique:
  • Position: Supine, arm over chest or on hand table. Tourniquet high arm.
  • Incision: Lateral over the RH, extending distally towards the ulna.
  • Interval (Kocher): Between Anconeus (Radial n) and ECU (PIN). The internervous plane is safe distally but the PIN is at risk proximally if extending too far anteriorly.
  • Dissection: Elevate Anconeus posteriorly. Incise capsule anterior to the LUCL.
  • Identify R-C joint.
  • Maneuver: Remove interposed soft tissue (Annular ligament may be folded in).
  • Reduction: Flexion and pronation usually reduces the head.
  • Repair: Annular Ligament repair is difficult. If stable, leave it. If unstable, reconstruct (Bell-Tawse procedure using Triceps strip).
  • Closure: Close the interval (Anconeus fascia) securely.

Pre-Operative Planning:

• Templating: Measure the normal side (if bilateral films available) to estimate radial head size.
• Ulna Length: If chronic, measure the ulnar length discrepancy. You may need to lengthen the ulna by 1-2cm.
• Implants: Have small fragment set (3.5mm), mini-fragment set (2.0/2.4mm for head/coronoid), and radial head replacement options (Simplex or Modular) available.

Surgical Pearls:

• The "Shotgun" Approach: For comminuted proximal ulna fractures, extend the incision distally. Expose the shaft. Reduce the shaft first to restore length. The proximal fragments often "explode" outwards.
• Coronoid Check: After fixing the ulna, check the coronoid. If fractured, it MUST be fixed (suture lasso or screws) as it prevents posterior instability.
• Head Height: If replacing the head, do not "overstuff" the joint. The prosthetic head should be level with the coronoid tip. Overstuffing causes stiffness and capitellar wear.
• LCL Repair: Reattach the LCL to the isometric point on the lateral epicondyle (center of curvature of the capitellum). Use suture anchors.
• Scope: If unsure about reduction, an arthroscope can be placed (if available) to view the R-C joint from inside.

For Chronic Monteggia:

• The ulna is usually shortened and angulated.
• Osteotomy: Proximal ulna.
• Correction: Lengthen (distract) and Angulate (usually extension for Type I) to "push" the radial head back.
• Fixation: Plate or Ex-Fix.

Osteola Procedure:

• Used for Missed Monteggia in older children.
• Involves:
  1. Open Reduction of Radial Head (remove fibrosis).
  2. Reconstruction of Annular Ligament (Triceps/Palmaris).
  3. Proximal Ulnar Osteotomy (Angulated + Lengthened).
  4. Fixation with Plate.
• Result: Good if less than 3 years from injury.

Annular Ligament Reconstruction:

• Indication: Chronic instability where the native ligament is incompetent.
• Graft Options:
  • Triceps Fascia (Bell-Tawse): Strip of triceps fascia left attached to the ulna, passed around the radial neck and sutured back to itself.
  • Palmaris Longus: Free graft.
• Technique:
  • Pass graft from posterior to anterior around the neck.
  • Anchor to the crista supinatoris of the ulna.
  • Critical: Do not make it too tight (loss of rotation).

Salvage:

• Indication: Painful chronic dislocation in mild-demand adult.
• Contraindication: Children (Growth arrest), DRUJ instability (will cause proximal migration).
• Result: Relieves pain but lose strength.

• Acute Reduced:
  • Splint in Supination (Type I) or Extension (Type II).
  • Weekly X-rays for 3 weeks.
• Post-Op:
  • Splint for 2 weeks.
  • Protected ROM (Hinge brace).
  • Avoid heavy lifting for 3 months.

Detailed Rehab Phases (Adult Monteggia):

• Phase 1 (Week 0-2):
  • Long arm splint.
  • Edema control (Elevation).
  • Finger/Shoulder ROM.
• Phase 2 (Week 2-6):
  • Removal of splint/sutures.
  • Hinged Elbow Brace (0-100 degrees).
  • Active Assist ROM: Flexion/Extension.
  • Forearm Rotation: Done with elbow at 90 degrees (protects LCL).
  • Avoid: Varus stress (shoulder abduction).
• Phase 3 (Week 6-12):
  • Wean brace.
  • Static progressive splinting if stiff (Turnbuckle).
  • Begin strengthening (Theraband).
• Phase 4 (Month 3+):
  • Work hardening.
  • Return to sport (if contact, wait for solid union 4-6 months).