Boyd Approach to the Proximal Radius and Ulna

What it exposes. The Boyd approach is a posterolateral exposure of the proximal radius and ulna that uses a single subperiosteal flap — containing anconeus and the origin of supinator — to protect the posterior interosseous nerve while giving access to the radial head, radial neck, annular ligament and proximal ulna. It is the classic approach when both the ulna and the proximal radius must be reached through one incision. Why this approach is chosen. It allows simultaneous exposure of the proximal ulna and the radial head or neck through a single posterolateral incision, and the subperiosteal flap technique protects the posterior interosseous nerve without requiring its formal identification or dissection. It is the standard approach for Monteggia fracture-dislocations, where the ulnar fracture and the radial head dislocation are addressed together, and for radial head arthroplasty or complex ORIF combined with ulnar fixation. Primary indications - Monteggia fracture-dislocations (Bado types I to IV) requiring ulnar fixation and radial head reduction.

• Radial head fractures (Mason III or IV, or comminuted) needing ORIF or arthroplasty.
• Annular ligament reconstruction or repair in chronic Monteggia or radial head instability.
• Complex proximal ulna fractures with associated radial head or neck injury.
• Revision surgery for failed radial head fixation or malunited Monteggia. Contraindications - Active infection over the proposed incision.
• Severe soft tissue compromise requiring an alternative exposure.
• An isolated radial head fracture better accessed through the Kocher or Kaplan approach (less invasive).
• Patient factors precluding lateral positioning. Alternative approaches

Position & landmarks. Position the patient in lateral decubitus with the affected arm on a padded arm board or bolster, elbow flexed 90 degrees; a supine position with the arm across the chest (shoulder internally rotated, elbow flexed) is a widely used alternative that allows easy conversion to anterior approaches. Apply the tourniquet high on the arm with exsanguination before inflation, and prepare from axilla to wrist including the hand so forearm rotation can be assessed intraoperatively. Palpate and mark the olecranon, the lateral epicondyle, the radial head (palpable anterior to the lateral epicondyle with forearm rotation) and the subcutaneous border of the ulna. The anconeus triangle — bounded by the olecranon, the lateral epicondyle and the radial head — is the key soft-tissue landmark. Plan a longitudinal incision along the subcutaneous ulnar border, centred over the radial head for isolated radial head work and extendable proximally and distally as required.

Work down through the layers along the subcutaneous ulnar border, develop the anconeus–ECU interval, then elevate the anconeus and supinator origin off the ulna as a single subperiosteal flap and reflect it radially — carrying the posterior interosseous nerve safely within the muscle mass. The internervous plane. The classical superficial interval lies between anconeus (radial nerve) and extensor carpi ulnaris (posterior interosseous nerve). The deep safety of the Boyd approach, however, does not come from internervous dissection: it comes from elevating the common origin of anconeus and supinator from the ulna as a single subperiosteal flap and reflecting it radially, with the posterior interosseous nerve carried within it.

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Structures at risk, by layer

Extensile options and approach variants. The incision extends proximally along the lateral border of the triceps tendon to expose the olecranon and distal humerus, and distally along the subcutaneous ulnar border for ulnar shaft fixation in Monteggia injuries (elevating extensor carpi ulnaris subperiosteally as needed). Never cross the interosseous space to the radius at any level, to avoid synostosis.

Closure. Reattach the subperiosteal flap (the anconeus and supinator origin) to the ulna using heavy absorbable or non-absorbable sutures through drill holes or to the periosteal sleeve, then close the fascia over extensor carpi ulnaris and close the subcutaneous tissue and skin in layers. A drain is rarely required. Immobilise the elbow in 90 degrees of flexion and neutral rotation for 7 to 10 days if an annular ligament repair was performed; otherwise encourage early gentle motion.

• Radial head arthroplasty — press-fit or cemented stems for comminuted Mason III or IV fractures.
• ORIF of radial head fractures — plate or headless screw fixation.
• Paediatric Monteggia fracture-dislocation — ulnar plate with radial head reduction.
• Annular ligament reconstruction or repair using a tendon graft.
• Open reduction of radial neck fractures in adults and children.
• Excision of the radial head (rarely indicated now).