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Both-Bone Forearm Diaphyseal ORIF (Radius & Ulna)

Surgical technique guide for open reduction and internal fixation of adult both-bone forearm diaphyseal fractures - restoring the radial bow and interosseous space, Henry vs Thompson approaches, PIN protection, Galeazzi and Monteggia, and radioulnar synostosis prevention

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intermediate
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Anatomical reduction and rigid plate fixation of the adult both-bone forearm to restore the radial bow and forearm rotation | intermediate

Surgical Imaging

Critical Danger Structures and Exam Traps

Posterior Interosseous Nerve (PIN)

Location: The PIN is the deep (motor) branch of the radial nerve, passing through the supinator muscle around the proximal radius, often via the arcade of Frohse. It is the structure most at risk during proximal radius exposure.

The fix: In the dorsal (Thompson) approach, identify the PIN within or distal to the supinator and protect it before subperiosteal dissection. In the volar (Henry) approach, fully SUPINATE the forearm so the PIN and supinator insertion rotate dorsally away from the surgical field at the radial neck.

Loss of the Radial Bow

The trap: Reducing the radius to length but leaving it 'too straight' (loss of the normal lateral radial bow) — the radius then cannot clear the ulna and forearm rotation is lost even with a healed, well-aligned-looking fracture.

The fix: Restore the magnitude AND location of the radial bow; compare intra-operatively with a contralateral forearm radiograph. Schemitsch & Richards correlated bow restoration with rotation and grip recovery.

Radioulnar Synostosis

Why it happens: Bony bridging across the interosseous space welds the radius and ulna, abolishing rotation. Risk rises with single combined incision, fractures at the same level, high-energy/comminuted injuries, associated head injury, and bone graft spilled into the interosseous space.

The fix: Use SEPARATE radius and ulna incisions; keep graft out of the interosseous space; avoid stripping the interosseous membrane; minimise soft-tissue trauma.

Compartment Syndrome

Recognition: Escalating analgesia-resistant pain, pain on passive finger/wrist stretch, tense swollen compartments — especially in high-energy or open injuries and after fixation. Pulselessness and paralysis are LATE.

The fix: Have a low threshold for compartment pressures and volar (+/- dorsal) fasciotomy. Never close skin under tension over a swollen forearm; consider leaving the fascia open.

Galeazzi — 'Fracture of Necessity'

Definition: Radial SHAFT fracture (classically distal third) with disruption of the distal radioulnar joint (DRUJ). Non-operative treatment fails — hence 'fracture of necessity'.

The fix: Anatomically reduce and plate the radius first; then test and address DRUJ stability (reduced and stable, reduced but unstable -> pin in supination, or irreducible -> open the DRUJ for interposed ECU/soft tissue).

Monteggia — Radial Head Dislocation

Definition: Proximal ULNA fracture with radial head dislocation (Bado I-IV by direction). The radial head dislocation is easily MISSED if the elbow is not imaged and the radiocapitellar line not checked.

The fix: Restore ulnar length, alignment and bow anatomically — this reduces the radial head in the great majority. Persistent dislocation means the ulna is not truly anatomic (residual angulation/length) or there is interposition.

Mnemonic

F.O.R.E.A.R.MFOREARM — Principles of Both-Bone ORIF

Mnemonic

S.A.F.E B.O.WSAFE BOW — Intra-operative Reduction Checklist

Why the Forearm Behaves as a Joint

The radius and ulna form a functional unit — a "forearm joint" — linked proximally at the proximal radioulnar joint (PRUJ), distally at the distal radioulnar joint (DRUJ), and along the shaft by the interosseous membrane. The radius rotates around a relatively fixed ulna to produce pronation and supination, sweeping in its characteristic lateral radial bow so that it clears the ulna.

Because of this, a displaced both-bone shaft fracture is biomechanically equivalent to an intra-articular fracture: anything less than anatomical restoration of length, rotation, axial alignment and the radial bow compromises rotation. This is the central principle driving the management of these injuries.

Surgical Indications

Absolute Indications

  • Displaced both-bone forearm fracture in an adult (the overwhelming majority) — closed treatment fails to maintain reduction
  • Open fractures — debridement plus fixation (plate fixation if soft tissues allow)
  • Galeazzi fracture (radial shaft + DRUJ disruption) — a "fracture of necessity"
  • Monteggia fracture (proximal ulna + radial head dislocation) — anatomic ulna fixation required
  • Fractures with compartment syndrome requiring fasciotomy — stabilise the skeleton at the same setting

Relative Indications

  • Minimally displaced both-bone fractures in adults — still usually fixed, as even minor malalignment costs rotation
  • Segmental or comminuted patterns — bridge plating principles, restore length/alignment/rotation
  • Polytrauma — early skeletal stabilisation aids overall management

Contraindications / Cautions

Absolute:

  • Active infection at the operative site (treat infection first)
  • Non-reconstructable, contaminated soft-tissue envelope (temporise with external fixation)

Relative:

  • Children with substantial remodelling potential — most paediatric both-bone fractures are managed by closed reduction or flexible intramedullary nailing rather than rigid plating
  • Severe comorbidity precluding anaesthesia

Goals of Fixation (the "Four Restorations")

  1. Length — restore each bone to length to balance the forearm
  2. Rotation — correct rotational malalignment (use the bicipital tuberosity/radial styloid relationship and oblique fracture-line keys)
  3. Axial alignment — eliminate angulation in both planes
  4. Radial bow — restore the magnitude and the apex location of the radial bow

Clinical Pearl

Examiner framing: 'I treat the forearm as a joint. My aim in a displaced adult both-bone fracture is anatomical open reduction and rigid internal fixation of each bone separately, restoring length, rotation, axial alignment and — critically — the radial bow, because the bow is what allows the radius to clear the ulna and rotate. I confirm the bow against the contralateral forearm and test rotation on the table.'

Why Cast Treatment Fails in Adults

  • Powerful deforming forces act on the radius: biceps and supinator (supinate the proximal fragment), pronator teres (mid-shaft) and pronator quadratus (pronate the distal fragment) — a cast cannot neutralise these
  • Maintaining the radial bow and interosseous space in plaster is unreliable; loss of the bow -> loss of rotation
  • Historical series of closed treatment in adults show high rates of malunion, loss of rotation and nonunion, which is why rigid plate fixation became the standard

Timing and Open Fractures

  • Open fractures: urgent debridement; tetanus and antibiotic prophylaxis; definitive plate fixation at the index procedure is appropriate for most Gustilo I-IIIA injuries with a clean, closable wound
  • Severe contamination / IIIB-C: consider temporary external fixation and staged definitive fixation
  • Compartment syndrome: emergent fasciotomy; do not delay for fixation logistics

Named Forearm Fracture-Dislocations — Must-Knows


Clinical Decision Scenarios

Use these scenarios to practise clinical reasoning and management decisions

CLINICAL SCENARIOStandard

CLINICAL PROMPT

"A 32-year-old man falls from a ladder and sustains a closed, displaced midshaft fracture of both the radius and ulna of his dominant forearm. He is neurovascularly intact. Walk me through your management and the principles of your operation."

PRACTICAL APPROACH
This is a displaced adult both-bone forearm fracture, which I treat as an intra-articular-equivalent injury because the forearm functions as a joint — the radius must rotate around the ulna. Closed treatment reliably fails to maintain length, rotation and the radial bow, so my plan is open reduction and rigid internal fixation of each bone. **Assessment and resus**: ATLS principles if needed, but here an isolated closed injury. I would document a careful neurovascular examination — specifically PIN (finger/thumb extension), median and ulnar function and the radial pulse — and actively assess for compartment syndrome (pain, pain on passive stretch, tense compartment) given it can evolve. I image the whole forearm including the wrist and elbow to exclude an associated DRUJ injury (Galeazzi) or radial head dislocation (Monteggia). **Operative plan**: General or regional anaesthesia, supine, arm on a radiolucent table, tourniquet, prophylactic antibiotics. I plan SEPARATE incisions — a Henry (anterior) approach to the radius and a separate subcutaneous-border approach to the ulna — to reduce synostosis risk. During the proximal radius dissection in the Henry approach I keep the forearm fully supinated to displace the PIN dorsally away from the radial neck. **Reduction and fixation**: I reduce the simpler fracture first (often the ulna) to restore length and act as a template, then the radius, restoring the radial bow — I compare against the contralateral forearm radiograph because bow restoration determines rotation. I fix each bone with a 3.5 mm plate: compression mode for transverse fractures, or an interfragmentary lag screw with a neutralisation plate for oblique patterns, aiming for at least three bicortical screws each side. I keep any graft out of the interosseous space. **Confirm and close**: I image in two planes, take the forearm through full pronation/supination on the table, reassess compartments and close without tension. I document post-op nerve function and counsel against routine plate removal because of refracture risk.
CLINICAL SCENARIOStandard

CLINICAL PROMPT

"A 40-year-old woman has a displaced fracture of the distal third of the radial shaft. The ulna is intact, but she has pain and tenderness at the wrist. What is the diagnosis you must exclude, and how do you manage it?"

PRACTICAL APPROACH
An isolated distal-third radial shaft fracture with wrist symptoms must raise the suspicion of a Galeazzi fracture — a radial shaft fracture with disruption of the distal radioulnar joint. It is called a 'fracture of necessity' because non-operative treatment reliably fails; it needs surgery. **Confirm the diagnosis**: I assess and image the DRUJ specifically — looking for widening of the DRUJ on the AP view, dorsal/volar displacement of the ulna relative to the radius on the lateral, radial shortening, and ulnar styloid base avulsion. I clinically test DRUJ stability (it may be masked while the radius is displaced). **Operative plan**: I anatomically reduce and plate the radius first, typically through a Henry (anterior) approach, with a 3.5 mm plate — restoring length, rotation and the radial bow. Restoring the radius is usually what restores DRUJ alignment. **Then assess the DRUJ** after radial fixation: (1) if it is reduced and stable through a range of rotation, I splint in supination; (2) if it is reduced but unstable, I pin the DRUJ in supination with one or two K-wires proximal to the joint for about six weeks, and consider the TFCC; (3) if the DRUJ is irreducible, I open it — the extensor carpi ulnaris tendon is the classic structure interposed in the joint, and it must be extracted to achieve reduction. **After surgery**: I immobilise in supination if the DRUJ was unstable/pinned, remove DRUJ wires at about six weeks, then mobilise forearm rotation. I counsel about stiffness and the importance of restoring rotation.
CLINICAL SCENARIOStandard

CLINICAL PROMPT

"Three months after both-bone forearm ORIF, a patient has united fractures but has progressively lost almost all pronation and supination. Imaging shows a bony bridge between the radius and ulna. What has happened, why, and how do you manage it?"

PRACTICAL APPROACH
This is radioulnar synostosis — a bony bridge across the interosseous space welding the radius and ulna and abolishing forearm rotation. It is one of the most feared complications of both-bone forearm fixation. **Why it happens / risk factors**: synostosis is more likely after a single combined incision and shared surgical bed, fractures at the same level in the two bones, high-energy or comminuted injuries, associated head injury (heterotopic-ossification tendency), extensive interosseous membrane stripping, and bone graft spilled into the interosseous space. Prevention is through separate incisions, atraumatic technique, preserving the interosseous membrane and keeping graft out of the interosseous space. **Confirm and characterise**: I obtain a CT to define the location, size and maturity of the synostosis and its relationship to the bones — this guides timing and the operative plan. **Management**: I would not operate on an immature bridge. Once the synostosis is radiographically mature with no further progression — which can be as early as 6 to 12 months after injury — I excise the bony bridge completely, restore the interosseous space, and may interpose tissue (such as a fat or muscle/free fascial graft). Complete primary excision alone gives a low recurrence rate, so routine adjuvant prophylaxis (single-dose radiotherapy or indomethacin) is not mandatory, though it can be considered in high-risk patients. I follow with aggressive early rehabilitation to maintain the rotation gained at surgery. **Counselling**: I would be honest that recurrence is a real risk and that the functional gain depends heavily on early, dedicated therapy after excision.

Both-Bone Forearm Diaphyseal ORIF — Exam Day Summary

Clinical summary

Evidence Base

Compression-plate fixation in acute diaphyseal fractures of the radius and ulna

Level IV
Anderson LD, Sisk D, Tooms RE, Park WI 3rd • J Bone Joint Surg Am
Clinical Implication: The landmark series that established rigid compression plating as the standard of care for adult diaphyseal forearm fractures, with union rates that closed treatment cannot match.
Verify on PubMed (PMID 1091653)

The effect of malunion on functional outcome after plate fixation of fractures of both bones of the forearm in adults

Level III
Schemitsch EH, Richards RR • J Bone Joint Surg Am
Clinical Implication: The defining paper proving that restoring the radial bow (magnitude and apex location) is the key determinant of forearm rotation and grip after both-bone ORIF; template against the contralateral forearm intra-operatively.
Verify on PubMed (PMID 1522093)

Compression-plate fixation of acute fractures of the diaphyses of the radius and ulna

Level IV
Chapman MW, Gordon JE, Zissimos AG • J Bone Joint Surg Am
Clinical Implication: Confirms high union and function with 3.5 mm plates and that immediate plate fixation of open forearm fractures is safe; the 3.5 mm system also minimises post-removal refracture compared with 4.5 mm plates.
Verify on PubMed (PMID 2918001)

Functional outcome after fracture of both bones of the forearm

Level IV
Goldfarb CA, Ricci WM, Tull F, Ray D, Borrelli J Jr • J Bone Joint Surg Br
Clinical Implication: ORIF reliably gives acceptable function, but residual deficits in pronation and grip persist and track with lost rotation, reinforcing why anatomical reduction and bow restoration matter.
Verify on PubMed (PMID 15773649)

Management of posttraumatic radioulnar synostosis

Level V
Bergeron SG, Desy NM, Bernstein M, Harvey EJ • J Am Acad Orthop Surg
Clinical Implication: Operate on synostosis only once the bridge is mature (radiographically), and complete excision alone gives low recurrence; routine radiotherapy or indomethacin prophylaxis is not mandatory.
Verify on PubMed (PMID 22751164)