Approach to the Radial Head and Neck

What it exposes. The lateral approaches give direct access to the radial head, the radial neck, the lateral capsule and the lateral collateral ligament complex. They are the workhorse exposures for radial head ORIF, radial head arthroplasty, lateral ligament reconstruction and release of post-traumatic stiffness, and they are continuous distally with the dorsal (Thompson) approach to the radial shaft. Why lateral (and which interval). Three lateral intermuscular intervals reach the radial head, and the nerve supply of each muscle defines the safe dissection. The Kocher (anconeus to ECU) is the workhorse posterolateral plane; the Kaplan (ECRB to EDC) sits anterolateral and better protects the LUCL; and the EDC split is the most nerve-sparing option for simple partial-head fractures. Position & landmarks. Supine with the arm on a hand table, shoulder internally rotated so the lateral elbow faces the surgeon, elbow flexed roughly 70 to 90 degrees over a supporting roll. Keep the forearm pronated throughout the deep dissection to protect the posterior interosseous nerve. Use a high-arm pneumatic tourniquet, exsanguinate with an Esmarch bandage, drape the arm free to allow full flexion-extension and pronation-supination for stability testing, and have an image intensifier available. Alternatives are the across-chest position (when a hand table is unavailable) and lateral decubitus or prone for combined posterior work. Palpate and mark before incision: the lateral epicondyle (centre of capitellar rotation), the radial head (just distal to the capitellum - rotate the forearm to feel it spin), the olecranon tip and lateral gutter, and the supinator crest of the ulna (the distal LUCL attachment). Trace the line of the LUCL from the lateral epicondyle toward the supinator crest.

Incision planning. The Kocher (posterolateral) incision is a gently curved line beginning just proximal to the lateral epicondyle and passing obliquely distally toward the posterior border of the ulna and ECU - this is the workhorse. The Kaplan (anterolateral) incision lies just anterior to this, centred over the radial head and aimed toward Lister's tubercle, developing the ECRB-EDC plane. Keep the incision directly over the radial head and avoid crossing the posterior skin crease at a right angle to minimise contracture.

Work down through the layers along the posterolateral (Kocher) line, developing the anconeus-ECU interval to the capsule, opening the capsule anterior to the lateral ulnar collateral ligament, and pronating to swing the posterior interosseous nerve away before any work at the neck.

Kaplan (anterolateral) variation. After skin and fascia, identify the ECRB-EDC interval anterior to the Kocher plane; develop it bluntly, retracting ECRB anteriorly and EDC posteriorly. The capsule is reached more anteriorly, keeping the LUCL safely posterior. Pronation remains essential because the PIN still crosses the field within supinator.

Structures at risk, by layer

The posterior interosseous nerve in detail. The PIN is the deep motor branch of the radial nerve. After piercing supinator - often through the tendinous arcade of Frohse - it winds around the radial neck within the muscle and emerges on the dorsal forearm to supply the extensor muscles, crossing the radial neck a short and variable distance distal to the radiocapitellar joint. Protection is non-negotiable: pronate the forearm to move the PIN away from the lateral field, stay proximal within about 2 cm of the head, avoid anterior retraction against the neck, and document finger and thumb extension before and after as a PIN function check.

The non-articulating safe zone for plating. Only the lateral non-articulating portion of the radial head and neck lacks contact with the lesser sigmoid (radial) notch of the ulna during rotation. This arc measures approximately 110 degrees and is the only place a plate can sit without impinging in the proximal radioulnar joint. Landmark it intra-operatively by pronating and supinating to find the arc that never rotates into the joint, referenced off Lister's tubercle dorsally and the radial styloid laterally. A plate outside this zone blocks rotation and causes pain and stiffness. Extensile options. Extend proximally along the lateral supracondylar ridge to expose the lateral column and capitellum (useful for capitellar fractures); the dissection stays lateral and the radial nerve is not encountered as long as you remain distal to the spiral groove. Extend distally by continuing the Kocher interval as the dorsal (Thompson) approach to the radial shaft - here the PIN becomes the dominant risk within supinator, so identify and protect it before any distal extension, developing the plane subperiosteally on the dorsal radius to keep the nerve safe with the supinator. Closure. Irrigate and confirm haemostasis; repair the capsule and any incised annular ligament with absorbable suture; repair the LUCL if it was released or damaged using suture anchors or bone tunnels to the lateral epicondyle at the centre of capitellar rotation (mandatory to prevent posterolateral rotatory instability); repair the common extensor origin if the Kocher interval was developed through it; close the fascia loosely to avoid a compartment problem; close skin and consider a drain; splint in extension or 90 degrees flexion only if stability demands, otherwise begin early motion. | Complication | Cause | Prevention | Management | |--------------|-------|------------|------------| | Posterior interosseous nerve palsy | Traction or retractor compression at the radial neck | Pronate, stay proximal, blunt retractors on bone | Splint, EMG at 3 weeks, explore if no recovery by 3 months | | Posterolateral rotatory instability | LUCL not repaired or repaired off-axis | Incise capsule anterior to LUCL; repair to centre of rotation | Ligament reconstruction; hinged external fixator | | Proximal radioulnar joint impingement | Plate placed outside the safe zone | Plate within the ~110-degree non-articulating arc | Remove or reposition hardware once healed | | Heterotopic ossification | Trauma and dissection in high-risk patients | Gentle handling; prophylaxis in head-injury or burn patients | Range of motion, indomethacin; excision when mature | | Stiffness and flexion contracture | Prolonged immobilisation | Early active motion in a stable construct | Static-progressive splintage; arthroscopic or open release | | Over-stuffing of the joint | Oversized radial head prosthesis | Size to the excised head and check with fluoroscopy | Revision to a correctly sized component | Post-operative care. From 0 to 2 weeks, splint for comfort only if the construct is stable, otherwise protect the lateral ligament repair avoiding varus and shoulder abduction, and begin active flexion-extension and pronation-supination within days. From 2 to 6 weeks, progress active motion, wean the splint, and avoid resisted extension for six weeks to protect the common extensor origin and lateral ligament repair. From 6 to 12 weeks, regain full active range with light strengthening and confirm radiographic healing or a stable prosthesis. Beyond 12 weeks, return to activity and work as comfort and range allow.

• Radial head ORIF - partial articular (Mason II) and selected reconstructable whole-head (Mason III) fractures.
• Radial head arthroplasty (replacement) - comminuted unreconstructable Mason III fractures, fracture-dislocations, and Essex-Lopresti lesions to restore longitudinal stability.
• Radial head excision or resection - salvage in selected low-demand patients, now largely replaced by arthroplasty.
• Annular ligament repair or reconstruction - chronic radial head dislocation and neglected Monteggia lesions.
• Lateral collateral ligament repair or reconstruction - posterolateral rotatory instability and terrible-triad reconstructions.
• Synovectomy and drainage - inflammatory arthritis and septic elbow.
• Lateral capsular release - post-traumatic elbow stiffness affecting flexion.

Guidelines, Registries & Global Practice Management of fractures of the radial head and neck has converged across examination systems. The principles - preserve the radial head where reconstructable, replace it when not, protect the posterior interosseous nerve by pronation, plate within the non-articulating safe zone, and repair the lateral collateral ligament - are common to international practice. Side-by-side principles (where guidance converges): | Body | Position on radial head fractures |

|------|-----------------------------------| | AO Foundation | Anatomic reduction and stable fixation of reconstructable partial and whole-head fractures; modular metallic prostheses for unreconstructable comminution; restore the lateral column and ligaments as part of complex instability | | AAOS (clinical practice guidance) | Operative treatment for fractures blocking rotation or associated with elbow instability; arthroplasty preferred over excision for comminuted fractures with ligamentous injury; avoid over-stuffing the joint | | BOAST (UK elbow fracture-dislocation) | Restore a stable, congruent elbow; fix or replace the radial head as a key secondary stabiliser; repair the lateral ulnar collateral ligament; early motion in a stable construct | Global practice variation. In high-resource settings, modular metallic radial head prostheses and precontoured head-specific plates are standard, and the lateral approach is routine. In resource-limited settings, the same surgical intervals are used with small-fragment reconstruction plates contoured into the safe zone, and silicone or excision strategies persist where prostheses are unavailable - with the recognised risks of proximal migration and silastic synovitis. Consent (globally applicable): discuss posterior interosseous nerve injury (mostly transient, but can be permanent), hardware irritation or impingement if the plate lies outside the safe zone, posterolateral rotatory instability if the lateral ligament is not restored, stiffness and heterotopic ossification, and the possibility of later revision to arthroplasty if fixation fails.