Distal Radial Malunion

Definition

 

Unacceptable position of radius post fracture

 

1.   Radial Shortening > 4mm at DRUJ

 

Radial Malunion Shortening

 

2.   Radial Inclination < 15°

 

Distal Radial Malunion APRadial Maluion Loss Radial Inclination

 

3.   Radial Tilt 

- > 15° Dorsal 

- > 20° Volar

 

Distal Radial Malunion Dorsal Tilt

 

4.   Articular incongruity > 2mm

 

Distal Radial Step OADistal Radial Step OA 2

 

5.  Positive ulna variance > 4mm

 

Radial Malunion

 

Biomechanics

 

Dorsal Tilting 

 

1.  Increases dorsal load

- maintain midcarpal alignment

 

2.  DISI / CIND

- midcarpal instability

- get DISI pattern without interosseous ligament disruption

- may be increased in patients with ligamentous laxity

 

Radial shortening

 

1.  Alter kinematics of DRUJ

 

2.  Ulnocarpal abutment

 

Clinical Presentation

 

DDx Pain 

- synovitis

- RC OA 

- ulnocarpal abutment

- DISI

- TFCC tear

- RSD

 

Functional Loss of ROM

- DF loss > PF

- supination loss > pronation

- weak grip

 

Investigation

 

PA film in neutral 

- wrist neutral

- elbow & shoulder at 90°

 

5 Measurements

 

1.  Radial inclination

2.  Radial length 

3.  Ulnar Variance 

4.  Radial Tilt  

5.  Radial Shift 

- radial Styloid from longitudinal axis

- compare to contralateral side

 

NHx Painless malunion

 

No evidence for development OA

 

Operative Management

 

Indications

 

Pain

Disability

 

Contraindications

 

OA in RCJ / carpus 

Osteoporosis

CRPS

 

Timing

 

Early > late results

- Jupiter 1996

- < 2/12 since fracture best

 

However, period of non operative treatment is often desirable

 

Surgical Options

 

1.  Ulna shortening

2.  Radial osteotomy

3.  Radial osteotomy + ulna shortening

4.  Radial osteotomy + ulna ablation

5.  Intra-articular ostetomy

6.  Soft tissue releases

 

Ulnar Shortening

 

Indications

- short radius, positive ulna variance

- acceptable alignment distal radius

- acceptable DRUJ articular surface

 

Distal Radial Osteotomy

 

Indications

- positive ulna variance / shortening

- dorsal tilt

- DRUJ reducible by radial osteotomy

- acceptable DRUJ articular surface

 

Options

- dorsal opening wedge

- volar opening wedge

- volar closing wege

 

Dorsal Opening wedge osteotomy

 

Distal Radial Malunion Dorsal OsteotomyDistal Radial Malunion Dorsal Osteotomy

 

Advantage

- lengthens the distal radius

- may be easier to correct in coronal and sagittal plane

- this makes it the most popular

 

Disadvantage

- dorsal approach / dorsal plate (extensor tendon issues)

- usually requires bone graft

- increased instability

- increased risk of non union

 

Template

- xray normal wrist

- calculate correction / size of bone graft

 

Dorsal opening wedge

- 3rd dorsal compartment

- expose distal radius

- can use half pins to control distal fragment

- check osteotomy site with II (metaphyseal, site of deformity)

- protect structures with homan retractors

- osteotomy with microsagittal saw

- correct radial articular surface in sagittal & coronal planes

- trapezoidal bi-cortical iliac crest autograft / synthetic graft

- dorsal locking plate

 

Volar opening wedge

 

Radial Malunion Volar Opening Wedge OsteotomyRadial Malunion Volar Opening Wedge Osteotomy Lateral

 

Advantage

- volar approach

- apply volar plate to gain correction

 

Disadvantage

- require dorsal approach to bone graft

 

Technique

- bed of FCR approach

- protect radial with homans, osteotomy

- apply volar plate

- then either leave gap dorsally or

- second dorsal approach to insert bone graft

 

Closing wedge osteotomy

 

Advantages

- volar approach  / plate better tolerated

- nil bone graft, direct bone to bone contact

 

Disadvantage

- can shorten radius / may need to perform ulna shortening as well

 

Distal Radial Osteotomy & Ulnar Shortening

 

Indications

- unacceptable radial alignment

- DRUJ not reduced by radius osteotomy

- acceptable DRUJ articular surface

 

Distal Radial Osteotomy & Ulnar Ablation

 

Indications

- unacceptable radial alignment

- DRUJ irreducible by radial osteotomy

- unacceptable DRUJ articular surface

 

Options

- Bower's hemiresection

- Darrach's

- Suave-Kapandji

 

Intra-articular Osteotomy

 

Issues

 

A.  Scaphoid facet malunion

- intra-articular osteotomy

- radial styloidectomy

- proximal row carpectomy

 

B.  Lunate facet malunion

- osteotomy 

- radio-lunate fusion

 

C.  Global wrist involvement

- early intra-articular osteotomy

- total wrist fusion

 

D.  Anterior / Posterior rim malunion

- simple bone resection

 

Soft Tissues Releases

 

Options

 

DRUJ volar capsulotomy 

- restores supination

 

DRUJ dorsal capsulotomy 

- restores pronation

 

+/-  Pronator Quadratus release