Distal Radius Corrective Osteotomy (Malunion)

Surgical Indications

Symptomatic Malunion — The Three Pillars

A distal radius malunion becomes a surgical indication when ALL THREE are present:

• Deformity beyond acceptable limits (dorsal tilt greater than 10-15 degrees, radial shortening greater than 3-5 mm, radial inclination loss greater than 5 degrees, intra-articular step greater than 2 mm)
• Symptoms attributable to the deformity — pain, weakness, restricted motion, ulnar-sided wrist pain
• Failure of non-operative management — typically a course of rest, activity modification, hand therapy, and a trial of splinting/medication

Absolute Indications

• Dorsal angulation greater than 20-25 degrees with significant functional impairment and no radiographic evidence of radiocarpal arthritis
• Radial shortening greater than 5 mm with positive ulnar variance and ulnocarpal abutment syndrome
• Intra-articular step greater than 2 mm in a young patient (under 45-50) with a discrete malunited fragment, no radiocarpal arthritis, and preserved cartilage
• Disabling DRUJ dysfunction (loss of pronosupination, painful clicking, arthrosis) that is at least in part due to the malunion
• Midcarpal instability (volar intercalated segment instability — VISI) secondary to the malunion

Relative Indications

• Radial shortening 3-5 mm with mild-moderate symptoms
• Dorsal tilt 10-20 degrees with weakness and functional limitation
• Concurrent carpal tunnel syndrome attributable to the malunited volar cortex (volar osteotomy decompresses simultaneously)
• Patient preference for correction after detailed counselling on risks, benefits, and prolonged recovery

Contraindications

Absolute:

• Established radiocarpal or DRUJ arthritis — salvage procedures (partial or total wrist fusion, arthroplasty) are preferred
• Active infection
• Medically unfit for anaesthesia with no reversible component

Relative:

• Heavy smoker unwilling to cease — markedly elevated nonunion risk; consider smoking cessation programme before surgery
• Complex regional pain syndrome (CRPS) — proceed cautiously; pre-op CRPS predicts worse outcomes
• Significant osteopenia that may compromise fixation
• Low functional demand with tolerable symptoms — non-operative management may be appropriate

Evidence Base

Outcomes of Corrective Osteotomy

• Systematic review (Lozano-Calderon 2006, PENDING PMID) — pooled functional outcomes from 15 case series; corrective osteotomy provides approximately 70-90% good-to-excellent results for pain relief and restoration of grip strength
• Pain reduction — most series report 60-80% of patients achieve meaningful pain reduction
• Grip strength improvement — average improvement of 30-50% of contralateral grip after correction
• Range of motion — modest gains in flexion-extension arc (typically 10-20 degrees improvement), more predictable correction of pronosupination if DRUJ is addressed

Patient-Specific Instrumentation

• 3-D CT templating with custom guides improves accuracy of correction — reported standard deviation of angular correction reduced from approximately 5 degrees (free-hand) to 2 degrees (guided) in comparative series
• Patient-specific plates (PSPs) allow precise pre-contoured fixation, particularly helpful in multiplanar deformity
• Cost-effectiveness debate — higher upfront cost balanced by reduced revision rates and improved functional outcomes in selected series

Concurrent DRUJ Procedures

• Ulnar shortening osteotomy is the most commonly performed concurrent procedure; transverse or oblique osteotomy with a compression plate
• Wafer resection (distal ulna arthroplasty) — alternative for positive ulnar variance less than 4 mm with TFCC pathology
• Sauvé-Kapandji — preferred when there is significant DRUJ arthrosis (creates a distal radioulnar fusion with a proximal pseudarthrosis)

Comparison of Osteotomy Techniques

Key Evidence

Deformity Anatomy — Distal Radius Malunion

Three-Plane Deformity

A distal radius malunion is a THREE-dimensional problem. The classic teaching is to address three radiographic parameters — but the actual deformity may include components in the axial, coronal, and sagittal planes plus rotation.

Pattern Recognition

• Colles' pattern (dorsal angulation, radial shortening, loss of inclination) — by far the most common. Treated with volar opening-wedge osteotomy at the metaphysis, restoring volar tilt
• Smith pattern (volar angulation) — less common. Treated with dorsal closing-wedge or volar opening-wedge on the dorsal cortex
• Barton-type intra-articular malunion — rare; intra-articular osteotomy only in young patients with preserved cartilage
• Die-punch malunion — depressed lunate facet fragment; technically demanding intra-articular correction

Osseous Anatomy Relevant to the Osteotomy

Metaphyseal Osteotomy Site

• The CORRECT location for the osteotomy is the METAPHYSIS — distal to the pronator quadratus insertion, proximal to the subchondral bone
• Too distal: enters the radiocarpal joint (intra-articular)
• Too proximal: risks damage to the median nerve and the FPL tendon (volar approach) or EPL tendon (dorsal approach)
• The volar cortex of the metaphysis is the SHORTENED side in a typical Colles malunion — this is where the opening-wedge is performed

Watershed Line

• A transverse ridge on the volar distal radius, approximately 2-3 mm proximal to the articular surface
• The DISTAL EDGE of any volar plate MUST lie proximal to this line — otherwise FPL attrition rupture can occur
• In corrective osteotomy, position the plate and confirm distal edge position with fluoroscopy

Neurovascular Anatomy

Volar Approach — Structures at Risk

• Median nerve — at risk during retraction; consider prophylactic release if there is concurrent carpal tunnel syndrome
• FPL tendon — runs along the volar radius; at risk from retractors and from the plate itself if not positioned correctly
• Radial artery — retracted radially with the brachioradialis; protect during the approach
• Palmar cutaneous branch of median nerve — emerges between FCR and radial artery at the wrist; protect by sub-FCR approach

Dorsal Approach — Structures at Risk

• EPL tendon — runs in the third dorsal compartment; release and retract
• Extensor tendon compartments 2, 3, 4 — retinacular flap should protect them; avoid dissection that violates individual compartments unnecessarily
• Posterior interosseous nerve (PIN) — resected to denervate the dorsal wrist capsule; provides wrist denervation in addition to correction
• Dorsal branch of the ulnar nerve — at the ulnar border of the approach; protect

DRUJ Anatomy

• TFCC — central disc and peripheral attachments; commonly attenuated or torn in malunion with positive ulnar variance
• DRUJ ligaments — dorsal and volar radioulnar ligaments; key stabilisers
• Ulnar styloid — non-union of the ulnar styloid base is common; usually asymptomatic but may require fixation if there is gross DRUJ instability
• ECU tendon subsheath — may be unstable in malunion with volar carpal supination

Carpal Alignment

Adaptive Carpal Malalignment

A distal radius malunion with dorsal tilt produces a compensatory CARPAL malalignment. Two patterns:

• Dorsal intercalated segment instability (DISI) — most common; capitate extends, scaphoid flexes; lunate follows dorsal tilt
• Volar intercalated segment instability (VISI) — less common; lunate flexes volarly; may indicate scapholunate or lunotriquetral ligament injury

Implication: Correcting the radial tilt often resolves the adaptive carpal malalignment. Intra-articular malunion is a different problem — requires direct articular correction.

Midcarpal Instability

A dorsal tilt of greater than 20-30 degrees may produce a volar midcarpal instability — the proximal row catches and reduces with a painful clunk. Restoring volar tilt is the key to managing this.

Positioning and Preparation

Patient position: Supine, arm abducted 90 degrees on a hand table, tourniquet applied to the upper arm (250-300 mmHg). Fluoroscopic image intensifier positioned on the opposite side of the table or from above, with AP and lateral images obtainable throughout.

Anaesthesia: General anaesthesia or regional (axillary brachial plexus block). Consider a pre-operative discussion of a supplemental regional catheter for post-op analgesia.

Pre-op templating:

• PA, lateral, and oblique radiographs of BOTH wrists
• CT with 3-D reconstruction is the standard for complex or multiplanar deformity
• Measure the contralateral wrist parameters — radial height, volar tilt, radial inclination, ulnar variance
• Calculate the osteotomy wedge size, location, and correction angle
• Plan concurrent procedures (ulnar shortening, wafer, Sauvé-Kapandji) if required
• Patient-specific cutting guides and pre-contoured plates can be manufactured from the CT data

Consent: Discuss risks of nonunion, under/over-correction, tendon rupture (FPL, EPL), neurovascular injury (median nerve, radial artery), DRUJ symptoms persisting, plate-related symptoms requiring removal, complex regional pain syndrome, stiffness, and the prolonged recovery (often 6-12 months to maximal improvement).

Volar Opening-Wedge Osteotomy — Step-by-Step

Step 1: Approach — Volar (Henry)

A standard volar approach to the distal radius, between FCR and the radial artery, with the pronator quadratus elevated from its radial origin. Extend the exposure distally into the carpal tunnel if concurrent release is planned.

Step 2: Identify the Osteotomy Level

On fluoroscopy, mark the osteotomy line. Aim for the metaphysis, perpendicular to the long axis of the radius in the coronal plane and at the apex of the deformity in the sagittal plane.

The CORRECT distal reference is approximately 15-20 mm proximal to the articular surface for a typical malunion. A line drawn perpendicular to the long axis of the radius at this level is the osteotomy reference.

Step 3: Make the Osteotomy

With a thin oscillating saw blade, make the osteotomy. Take care to:

• Cool the saw blade with saline to prevent thermal necrosis
• Stop at (but do not breach) the dorsal cortex — leave it as a hinge
• Confirm the cut is complete and the fragment is mobile on the dorsal hinge with an osteotome if needed

Step 4: Open the Wedge

Insert a small laminar spreader or osteotome into the osteotomy and gradually open the volar cortex. The dorsal cortex acts as a hinge. The opening should be symmetric.

The wedge height is determined pre-operatively from templating. A rough rule: 1 mm of opening corresponds to approximately 1 degree of tilt correction in a typical radius. (Use the pre-op plan and intra-operative imaging — the rough rule is for guidance only.)

Step 5: Insert the Bone Graft

The structural graft (tricortical iliac crest autograft is gold standard) is shaped to fit the wedge defect. Alternatives: structural allograft, synthetic calcium phosphate wedges, or cancellous chips with internal fixation only.

Insert the graft into the wedge, ensuring it is fully seated and provides rigid structural support. The graft should fill the gap without overstuffing.

Step 6: Provisional Fixation with K-wires

Insert 2-3 K-wires across the osteotomy and graft to provide provisional fixation. Confirm position with fluoroscopy.

Step 7: Apply the Volar Locking Plate

A pre-contoured volar locking distal radius plate is applied. Ensure the DISTAL EDGE of the plate lies PROXIMAL to the watershed line to avoid FPL attrition rupture. Distal locking screws are placed in the subchondral bone under fluoroscopic guidance.

Step 8: Final Imaging

Obtain final AP, lateral, and oblique fluoroscopic images. Confirm:

• Volar tilt restored to approximately 11 degrees
• Radial height restored to within 2 mm of contralateral
• Radial inclination restored to 22-23 degrees
• Ulnar variance neutralised
• No intra-articular screw penetration
• Plate distal edge proximal to the watershed line
• Graft well-seated

Dorsal Closing-Wedge Osteotomy — Step-by-Step

Step 1: Approach — Dorsal

Dorsal approach to the distal radius, longitudinal incision centred over Lister's tubercle. Release the EPL sheath and retract the EPL tendon. Reflect the extensor retinaculum to expose the third and fourth extensor compartments.

A PIN neurectomy is often performed for denervation of the dorsal wrist capsule.

Step 2: Mark the Wedge

Plan the closing-wedge on the lateral view: a wedge of bone is removed from the dorsal cortex with the base dorsally and the apex on the volar cortex. The size of the wedge determines the correction.

Step 3: Two Parallel Cuts and Wedge Removal

Make two parallel transverse cuts in the metaphysis, leaving the volar cortex intact as a hinge. Remove the wedge of bone. Close the osteotomy with the volar hinge intact.

Step 4: Fix with Dorsal Plate or K-wires

Apply a dorsal plate (low-profile preferred to reduce EPL attrition), or fix with K-wires and a volar neutralisation plate. Confirm correction with fluoroscopy.

Intra-articular Osteotomy — Step-by-Step

Indication

Young patient (typically under 45), discrete intra-articular step, no radiocarpal arthritis, fragments large enough to hold fixation.

Technique

• Volar or dorsal approach depending on the location of the step
• Capsulotomy to expose the joint
• Mobilise the displaced fragment
• Reduce the fragment anatomically under direct vision
• Fix with headless compression screws, mini-fragment plates, or K-wires
• Confirm articular reduction with intra-operative imaging; consider arthroscopy

Concurrent DRUJ Procedure

Decision-Making

• Positive ulnar variance with ulnocarpal abutment AND/OR DRUJ arthrosis — concurrent procedure is indicated
• Choice depends on TFCC status, arthrosis, ulnar variance, and patient factors

Ulnar Shortening Osteotomy

• Separate incision over the distal ulna
• Transverse or oblique osteotomy at the diaphysis
• Shorten to neutral variance (0-1 mm)
• Apply a dedicated ulnar shortening compression plate (6-hole, 7-hole)
• Aim for compression at the osteotomy

Wafer Resection (Distal Ulna Arthroplasty)

• Indication: positive ulnar variance less than 4 mm, TFCC pathology amenable to repair
• Resect 2-4 mm of the distal ulnar head through a small arthrotomy
• Preserve the ulnar styloid base and TFCC attachments
• Consider arthroscopic wafer resection

Sauvé-Kapandji Procedure

• Indication: DRUJ arthrosis with positive ulnar variance, failed ulnar shortening
• Distal radioulnar arthrodesis with creation of a proximal ulnar pseudarthrosis
• Resect a 1-1.5 cm segment of ulna proximal to the arthrodesis
• Fix the arthrodesis with screws or a plate

Post-operative Protocol

Early Phase (Day 0-14)

• Splint: Short-arm volar splint in neutral wrist position for 10-14 days
• Elevation: Elevate the hand above heart level for the first 48-72 hours
• Analgesia: Multimodal — paracetamol, NSAIDs (consider gastroprotection), opioids for breakthrough
• Finger motion: Encourage active flexion and extension of all digits from day 1 to prevent stiffness and adhesions
• Oedema control: Compressive dressing, hand elevation
• Wound check: At 48-72 hours; inspect for haematoma, infection, dressing issues

Intermediate Phase (Weeks 2-6)

• Splint removal: At 10-14 days; transition to a removable wrist splint for comfort
• Suture removal: 10-14 days
• Radiographs: At 2 weeks and 6 weeks
• Hand therapy: Begin formal therapy at 2-4 weeks — active and passive wrist ROM, oedema control, scar management
• Grip strengthening: Begin at 6 weeks if union is evident

Later Phase (Weeks 6-12+)

• Progressive strengthening: From 6 weeks with confirmed union
• Return to light activities: 6-8 weeks
• Return to manual work / sport: 3-6 months depending on union and functional recovery
• Plate removal consideration: If symptomatic, typically after 6-12 months once union is mature

Rehabilitation Goals

• Wrist flexion 60-70 degrees; extension 50-60 degrees
• Pronation 70-80 degrees; supination 70-80 degrees
• Grip strength 70-80% of contralateral
• Functional return to ADLs and most work activities

Special Case: Intra-articular Malunion in Young Patients

Indication for Intra-articular Osteotomy

• Age typically under 45-50
• Discrete malunited articular fragment with step greater than 2 mm
• No radiocarpal arthritis on imaging (or minimal chondral damage at arthroscopy)
• Patient willing to accept prolonged rehabilitation and the risk of post-traumatic arthritis

Pre-operative Workup

• CT with 3-D reconstruction to map the malunited fragment
• Arthrogram or MRI to assess TFCC, scapholunate ligament, and chondral surfaces
• Wrist arthroscopy at the time of surgery to assess cartilage and aid reduction

Technique Specifics

• Use a volar or dorsal approach depending on the location of the displaced fragment
• Capsulotomy to expose the joint surface
• Mobilise the fragment; protect the dorsal and volar capsular attachments
• Reduce the fragment anatomically under direct vision
• Fix with headless compression screws (e.g. Acutrak, Herbert) or small-fragment plates
• Confirm reduction with arthroscopy and fluoroscopy
• Address associated intercarpal ligament injuries if present (often needed)

Outcomes

• Best results in young patients with early correction (within 6-12 months of injury)
• Higher rate of post-traumatic arthritis in long-term follow-up
• Compared with extra-articular osteotomy, the technical demands are higher

Special Case: Malunion with Concurrent Carpal Tunnel Syndrome

Clinical Picture

A distal radius malunion with dorsal tilt and radial shortening can produce:

• Adaptive carpal malalignment (DISI)
• Increased pressure within the carpal tunnel from the malunited volar cortex
• Acute or chronic carpal tunnel syndrome

Surgical Management

• Plan for volar corrective osteotomy AND carpal tunnel release in the same anaesthetic
• Use an extended volar approach that allows both procedures
• The volar osteotomy often decompresses the carpal tunnel by restoring radial anatomy
• Consider adding a formal open carpal tunnel release if pre-op symptoms are significant

Special Case: Elderly Patients with Lower Demand

Considerations

• Lower functional demand may justify non-operative management in some elderly patients
• However, patients with significant pain, loss of independence, or disability can still benefit from corrective osteotomy
• Decision-making should consider physiological age, comorbidities, hand dominance, and patient preference

Modifications

• Accept slightly less precise correction in low-demand patients
• Use allograft or synthetic wedges to avoid iliac crest harvest morbidity
• Consider shorter post-op immobilisation to allow earlier return to function

Special Case: Concurrent DRUJ Arthroplasty Considerations

Sauvé-Kapandji Procedure

• Indication: DRUJ arthrosis with positive ulnar variance, particularly if a concurrent radial osteotomy is being performed
• Technical: Fuse the distal radioulnar joint with a screw; create a proximal ulnar pseudarthrosis by resecting 1-1.5 cm of ulna
• Outcomes: Reliable pain relief and restoration of pronosupination

Ulnar Head Prosthesis (Distal Ulnar Arthroplasty)

• Indication: DRUJ arthrosis with failed prior procedures
• Available as metallic or pyrocarbon prostheses
• Consider in selected low-demand patients with intact sigmoid notch