Distal Radius Fracture

Synonyms
Wrist fracture

INTRODUCTION

Definition

Fracture of the distal radius with or without fracture of the distal ulna. 

Epidemiology

  • Most common upper extremity fracture (> 300,000 per year) in the United States.
    • Accounts for 17.5% of all fractures in adults.
  • There is a bimodal distribution:
    • Occurs in younger patients due to high energy mechanisms, e.g., motor vehicle accident and fall from height. 
    • In elderly persons with osteoporotic bone it is seen after low-energy falls (i.e. FOOSH).
  • More common in females (2-3:1).
  • Open injuries more common in young patients.
  • Most common in white women that are older than age 50 years.
  • Risk factors: Osteoporosis.
    • There is a high incidence of distal radius fractures in women > 50 years old. DEXA scan is recommended for women with distal radius fractures.
    • Distal radius fractures are a predictor of subsequent fractures.

Relevant Anatomy

  • The articular surface is biconcave and articulates with scaphoid (via scaphoid fossa/facet), lunate (via lunate fossa/facet) and distal ulna (via ulnar/sigmoid notch). 
  • The distal radius is responsible for 80% of axial load.
  • Distal radioulnar joint (DRUJ) is a joint where there is articulation with ulna at the sigmoid notch.
  • Lister tubercle (dorsal tubercle) is a small dorsal prominence. It is the landmark for dorsal approach to wrist.
  • The metaphysis of the distal radius has a thin cortex and is therefore vulnerable to bending forces.
  • The brachioradialis muscle is the major deforming force.

Mechanism of Injury

The mechanism is usually fall onto an outstretched hand (FOOSH). But it can also be due to higher energy mechanisms, e.g. motor vehicle accident (MVAs). 

Classification

Most classification are descriptive and they largely fail to help predict treatment or prognosis.
  • Eponyms: These predate radiography.
    • Colles-fracture: Low energy extra-articular fracture that is dorsally displaced. 
    • Smith-fracture: Low energy extra-articular fracture that is volarly displaced. 
    • Barton-fracture: Fracture-dislocation of radiocarpal joint with intra-articular fracture that involves the volar or dorsal lip (called volar Barton or dorsal [reverse] Barton fracture). 
    • Chauffer’s fracture: Fracture of the radial styloid.
    • Die-punch fracture: Depressed fracture of the lunate fossa of the articular surface of the distal radius.
  • Other classification:  
    • AO: Comprehensive classification. Mostly used. 
    • Frykman: Based on joint involvement (radiocarpal and/or radioulnar) with or without ulnar styloid fracture.
    • Fernandez: Based on mechanism of injury.
    • Melone: Divides intra-articular fractures into 4 types based on displacement.

CLINICAL FEATURES

Symptoms

  • The patient will present with wrist pain and swelling.
  • Will usually present after a fall onto outstretched hand (FOOSH)

Signs

Inspection: Swelling, hematoma/ecchymosis, deformity at the wrist if displaced (e.g. dinner fork)
Palpation: Diffuse wrist tenderness.
  • Examine for concurrent anatomic snuffbox (scaphoid fracture) and ulnarsided wrist tenderness (TFCC injury).
Neurovascular examination: Assess median and ulnar nerve function.
  • Acute carpal tunnel syndrome (CTS): The patient will present with progressive, evolving paresthesias and disproportionate pain. CTS after a distal radius fracture requires emergency median nerve decompression (carpal tunnel release).
  • Ulnar nerve palsy: Can occur after a high-energy displaced distal radius fracture.

Associated Injuries
DRUJ injury: DRUJ must be evaluated. The patient usually has ulnarsided wrist tenderness.  
Radial styloid fractures: This indicates higher energy mechanism.
Soft tissue injuries: Are seen in 70 %.
  • TFCC injury (40 %).
  • Scapholunate ligament injury (30 %).
  • Lunotriquetral ligament injury (15 %).

DIAGNOSIS

X-ray

Recommended views: Frontal (AP), lateral, oblique.
  • Evaluate intraarticular involvement: Evaluate fracture pattern, gap, and step-off.
  • Assess DRUJ involvement: This can be asses with the true lateral radiograph for DRUJ alignment.
Findings
  • Normal findings
    • Radial height: Average is 11 mm.
    • Radial inclination: Average is 22°.
    • Volar tilt (lunate fossa inclination): Average is 11°.
    • Ulnar variance: Shouled be neutral. With fracture it can be positive or negative.
      • Assessed with forearm in neutral rotation.
      • Compare to contralateral side.
  • Fracture: 50 % of the distal radius fractures are intraarticular. 
  • Associated fractures: Unar styloid, distal ulna, carpus.
    • Isolated fracture of radial styloid (chauffeur fracture): Observe that it may be associated with scapholunate ligament disruption.

Computer Tomography (CT)

CT is indicated to evaluate the intra-articular involvement and for surgical planning.

Magnetic Resonance Imaging (MRI)

MRI is indicated to look for occult fracture, bone contusion and associated soft tissue injury (TFCC injuries, scapholunate ligament injuries, lunotriquetral injuries). 

TREATMENT

Overview

  • The goals of all treatment are to maintain optimize the anatomy, reduction until union, restore function, prevent symptomatic posttraumatic radiocarpal osteoarthrosis.
  • Treatment factor to be considered are age, medical condition, activity demands, bone quality, fracture stability, and associated injuries.
  • Treatment options include:
    • Closed reduction and cast immobilization
    • Closed reduction and percutaneous pinning with or without external fixation.
    • Open reduction and internal fixation (ORIF).

Nonoperative Treatment

Indication: Minimally displaced low-energy injuries, especially in functionally low-demand patients. These are likely to remain stable.
  • Postreduction benchmarks (American Academy of Orthopaedic Surgeons guideline):
    • Radial shortening should be less than 3 mm.
    • Dorsal articular tilt should be less than 10°.
    • Intraarticular step-off should be less than 2 mm.
Metod: Cast immobilization, e.g. sugar tong plaster splint with three-point mold. 
  • Keep MCP and IP joints free for motion.
  • Closed reduction indicated in displaced fractures with abnormal radiographic parameters, especially in functionally high-demand patients.
  • Closed reduction indicated in displaced fractures.
    • Dorsal hematoma block with local anesthetic.
    • Finger traps, upper arm counterweight for ligamentotaxis.
    • Recreate deformity, manipulate distal fragment.
Follow up:
  • X-ray control after 7-10 days.
    • In some cases the radiographs at obtained weekly for first 3 weeks.
  • Cast removal and a clinical control after 4-6 weeks. 

Operative Treatment

Indications: Loss of reduction correlates with increasing age.
  • Surgical treatment indications relate to infirmity, functional demands, tolerance of deformity, and personal preferences but also age.
  • Injury and patient characteristics meriting a discussion of surgical treatment include the following:
    • Loss of reduction, including ulnar variance 5 mm or more positive; dorsal articular tilt ≥15° (ie, volar apex angulation); and loss of radial inclination >10°.
    • Articular gap or step of 2 mm or more
    • Unstable volar extra-articular fractures (Smith fracture)
    • Intra-articular volar shear fracture (Barton fracture)
    • Open fractures
    • Fractures with associated neurovascular injuries
    • Fractures with associated intercarpal ligament injuries
    • Multiple trauma, such as bilateral distal radius fractures or the need to use
Method:
  • Closed reduction and percutaneous pinning (CRPP).
  • External fixation.
  • Distraction plating.
  • Open reduction with internal fxation (ORIF).
  • Fragment-specifc.
  • Intramedullary nailing.
  • Arthroscopic assistance.

Treatment Choice
MethodIndication
CRPPExtra-articular fracture with stable volar cortex.
External fixation
  • Open fractures.
  • Highly comminuted fractures.
  • Medically unstable patients unable to undergo a lengthy procedure.
ORIF
  • Dorsal angulation > 10-20°.
  • Displaced intra-articular fractures > 2 mm.
  • Radial shortening > 5 mm.
  • Associated ulnar fracture. Observe that this does not include ulnar styloid fractures.
  • Articular margin fractures (dorsal and volar Barton fractures).
  • Comminuted and displaced extra-articular fractures (Smith’s fractures).
  • Die-punch fractures.
  • Progressive loss of volar tilt and loss of radial length following closed reduction and casting. This includes also follow-up control x-ray.
Distraction plating Alternative to external fixation in highly comminuted fractures or in elderly patients with severe osteoporosis.

Surgical Techniques

Closed reduction and percutaneous pinning (CRPP): Kan be used with Kapandji intrafocal pinning.
External fixation:
  • Might be used with bridging and nonbridging techniques described.
  • Role in fractures with open contaminated wounds.
  • Diffcult to restore articular alignment and volar tilt.
  • Overdistraction may lead to increased risk of complex regional pain syndrome (CRPS).
Distraction plating (bridge plating, “internal ex fix”):
  • It will secure the second or third metacarpal and radial shaft.

COMPLICATIONS AND PROGNOSIS

Complications

Prolonged immobilization (> 8 weeks): May lead to wrist and digit stiffness, muscle atrophy, and disuse
osteopenia.
Median nerve palsy: May be acute or delayed onset and is the most common complication following a distal radius fracture.
Complex regional pain syndrome (CRPS). Also called reflex sympathetic dystrophy (RSD). Vitamin C supplementation has been recommended to prevent incidence of CRPS postoperatively. This includes doses of at least 500 mg/day for 50 days which may decrease the incidence of CRPS in women older than age 50 treated for a distal radius fracture.
Extensor pollicis longus (EPL) tendon rupture:
  • Most common extensor tendon injured.
  • Occurs most commonly as a late complication following closed treatment because of sheath hematoma, attritional wear and/or vascular insuffciency near the Lister tubercle. May also occur after volar plating volar due to due to drill-bit penetration or dorsally prominent screws.
  • Typically presents as a painless, acute loss of thumb extension.
  • Can be treated with palmaris longus (PL) intercalary autograft or extensor indicis proprius (EIP)-to-EPL tendon transfer
Flexor pollicis longus (FPL) tendon rupture: Most common rupture after volar plating. Occurs potentially due to improper plate placement distal to watershed zone.
Nonunion and malunion:
  • Nonunion is uncommon.
  • Asymptomatic malunion in a functionally low-demand patient does not require treatment.
Osteoartritis (osteoarthrosis): Radiocarpal osteoarthrosis can occur after an intraarticular distal radius fracture with residual step-off. It does not necessarily correlate with patient-reported symptoms.

Prognosis

Poorer functional outcomes are associated with:  
  • Worker’s compensation.
  • Low socioeconomic status.
  • Low education levels.
  • Low bone density (osteoporosis).
Successful outcomes are seen with
  • Good reduction, especially articular reduction.
  • Restoration of anatomy.
  • Early efforts to regain motion of wrist and fingers.
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References