Scaphoid ORIF - Dorsal Approach (Proximal Pole)

Indication. Operative fixation of a proximal pole scaphoid fracture through a dorsal approach, chosen when the fragment must be visualized directly and/or a vascularized graft from the dorsal radius is planned. The absolute indications are: - Displaced proximal pole fracture (Herbert B3) — displacement greater than 1mm.

• Proximal pole non-union — failed conservative management or delayed presentation.
• Avascular necrosis (AVN) of the proximal pole — requires a 1-2 ICSRA vascularized bone graft plus fixation. Relative indications are a non-displaced proximal pole fracture in a high-demand patient (athlete, manual labourer), a failed volar approach to the proximal pole (inadequate visualization or fixation), and a proximal pole fracture with a scapholunate ligament injury that allows direct SL repair at the same sitting. Contraindications. Absolute: severe comminution where the fragment is too small for any fixation (salvage may be needed) and active infection (debride first). Relative: severe osteoporosis (consider K-wire augmentation), and a waist or distal pole fracture — for these the volar approach is preferred for better access and to avoid the stiffness the dorsal approach can cause. Pre-operative imaging is the whole plan. - Plain radiographs — PA, lateral, scaphoid view (PA with ulnar deviation) and oblique.
• CT — assess fragment size (can it accept a screw?), displacement, comminution and any arthritic change.
• MRI — essential to assess AVN; a dark T1 signal predicts the need for a vascularized graft. Decision algorithm. (1) Fragment size — greater than 25% of scaphoid length is required for a retrograde screw. (2) AVN — if present on MRI, plan a 1-2 ICSRA vascularized graft. (3) Screw trajectory — retrograde (proximal-to-distal) preferred; antegrade (distal-to-proximal) if the fragment is too small. (4) Graft — non-vascularized cancellous for non-union without AVN; vascularized ICSRA for AVN. Equipment checklist. Mini C-arm positioned for perfect scaphoid views BEFORE draping; a headless compression screw set (lengths 16-30mm); a 0.045-inch guidewire and cannulated drill bits; K-wires for provisional fixation and joystick control; microsurgical instruments if an ICSRA graft is planned; and a wrist bump for 10-20 degrees of flexion. Consent specifically for the 30-50% AVN risk despite optimal surgery, prolonged healing (12-20 weeks), superficial radial nerve numbness or neuroma, possible EPL irritation/rupture, non-union (15-20%), and the possible need for a bone graft (and, with AVN, a vascularized graft or later salvage). Setup. Supine, arm on a hand table, forearm pronated with the wrist flexed 10-20 degrees over a bump (flexion opens the dorsal scaphoid space and brings the proximal pole into the field — the opposite of the volar approach). Test the C-arm for perfect PA, lateral and oblique scaphoid views BEFORE draping. Loupe magnification is recommended for nerve and vessel identification.

The goal: expose the proximal pole through the dorsal EPL-EDC interval over Lister's tubercle, preserve the dorsal ridge blood supply, reduce the fracture anatomically, and stabilize it with a headless compression screw — adding a vascularized 1-2 ICSRA graft when the fragment is avascular. The exposure (Steps 1-5 below) is the heart of the operation and is laid out in full.

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Rehabilitation | Phase | Timing | Immobilisation | Therapy & monitoring | |-------|--------|----------------|----------------------| | 1 | 0-2 weeks | Thumb spica splint, wrist neutral, thumb column, IP joint FREE | Elevation, ice, finger active range of motion; suture removal at 10-14 days | | 2 | 2-8 weeks | Thumb spica CAST (longer than for a waist fracture) | Light ADLs with the splint; X-rays at 2 and 6 weeks — expect minimal callus (intra-articular bone) | | 3 | 8-12 weeks | Removable thumb spica IF early union signs | Hand therapy AROM and gentle strengthening; CT often needed to confirm union | | 4 | 3-6 months | Splint for heavy tasks only | Progressive strengthening and proprioception; MRI at 3-6 months if AVN is suspected (T1 signal) | Proximal pole fractures take longer to unite than waist fractures — typically 12-20 weeks (versus 8-12 for the waist) — so immobilization is extended. Plain films are often inadequate to confirm proximal pole union, so a CT is frequently required. Expected outcomes with ORIF: union in 80-85% of acute fractures, 80-90% of contralateral wrist motion, 85-95% of contralateral grip at one year, and unrestricted activity at 4-6 months after solid union. Contact sports are deferred to 6 months (later than for waist fractures). Counsel the patient that AVN can still develop in 30-50% despite optimal surgery. Complications

Epidemiology & natural history. The proximal pole is the unforgiving part of the scaphoid: proximal pole fractures carry the highest AVN rate (30-50%) and the highest non-union rate (15-20%, versus 5-10% for the waist). Acute proximal pole fractures unite in 80-85% with ORIF (versus 60-70% non-operative), over 12-20 weeks. Left untreated, a scaphoid non-union progresses to SNAC arthritis in around 95% of cases within 10 years (Kerluke) — which is why achieving union matters. Pathoanatomy — the scaphoid blood supply (the critical concept). The scaphoid's vascularity is the key to the whole topic. The dorsal vessels (70-80%) are branches of the radial artery that enter at the dorsal ridge (junction of the middle and proximal thirds) and supply the entire proximal pole by retrograde intraosseous flow. The volar vessels (20-30%) enter at the tubercle and waist and supply only the distal 20-30%. The proximal pole has no direct blood supply — it is entirely dependent on retrograde flow from the dorsal ridge, so a proximal pole fracture interrupts that flow and renders the fragment avascular. This is why a dorsal exposure must minimise stripping at the dorsal ridge, while still giving access to the very same dorsal radius vessels used for ICSRA grafting. The volar approach is the least traumatic to this supply, but it cannot reach the proximal pole directly — hence the dorsal approach for this fracture. Surgical anatomy. The 3rd extensor compartment contains the single EPL tendon, which courses around Lister's tubercle; the 4th compartment contains the four EDC tendons plus EIP. The dorsal capsule is reinforced by the dorsal radiocarpal (DRC) and dorsal intercarpal (DIC) ligaments, and the dorsal scapholunate ligament (the strongest part of the SL complex and the primary stabilizer) sits just ulnar to the proximal scaphoid. The superficial radial nerve crosses the dorsal wrist radially; the radial artery gives off the dorsal carpal branch that supplies the scaphoid; and the 1-2 and 2-3 intercompartmental supraretinacular arteries run on the dorsal radius between compartments and are the basis of the vascularized grafts. Classification — SNAC arthritis staging (the long-term consequence of a missed or failed proximal pole fracture):

Outcomes & comparative evidence. With ORIF, acute proximal pole fractures achieve 80-85% union over 12-20 weeks; functional recovery is around 80-90% of contralateral wrist motion (extension most affected by the dorsal approach) and 85-95% of contralateral grip at one year, with 80-85% good-to-excellent results at 5 years. The dorsal approach is recommended specifically for the proximal pole (better visualization and ICSRA access, at the cost of a higher stiffness rate than the volar approach). Biomechanically, retrograde and antegrade screws achieve equivalent compression with perfect central placement; the choice is driven by fragment size. For a confirmed AVN proximal fragment, a vascularized graft roughly doubles union compared with non-vascularized fixation (Merrell); across all non-unions the two graft types are broadly similar (Pinder), so the vascularized advantage is concentrated in AVN.