Smith's Fracture

Definition/Description

Smith's Fracture is a fracture of the distal end of the radius caused by a fall on the back of the hand, resulting in a volar displacement of the fractured fragment. It is also known as a reverse Colles fracture. The Smith's fracture was named by Irish surgeon Robert William Smith in 1847, however, this injury was first named for French Physician Jean-Gaspard-Blaise Goyrand (1746-1814) and is commonly known as a Goyrand fracture in French literature.

Aetiology

The cause of the fracture is a fall on a flexed wrist or as a direct blow to the dorsal aspect of the wrist accompanied by a volar displacement of the distal radius can occur with a fall onto the palm of the hand.

Mechanism of Injury

Injury resulting from a fall on the palm of the hand, the dorsum or ulno‐dorsum of the hand, or a fisted hand or a direct blow to the back of the wrist.

The mechanism of injury included:

• tripping forward while walking or
• falling while cycling or
• slipping backward

Epidemiology

The injury site, i.e., the distal radius, is the most common fracture site in the upper limb, accounting for the second most common fracture in the elderly. Smith fracture makes up approximately 5% of all combined radial and ulnar fractures.

The highest incidence of Smith's fractures is in young males after sustaining high-energy falls and in elderly females who suffering a low energy fall due to osteoporosis

Classification:

Smith fractures divide into three types:

• Type I - most common type, accounting for about 85% of cases, is an extra-articular fracture through the distal radius
• Type II - less common, accounting for approximately 13%, is an intra-articular oblique fracture, also referred to as a reverse Barton fracture
• Type III - uncommon, less than 2%, is a juxta-articular oblique fracture

Clinical Presentation

The patient may present with an above mentioned traumatic event with the following clinical features:

• swelling,
• pain
• deformity of the distal forearm

Diagnosis

X-rays

AP and the lateral radiograph of the wrist can diagnose the fracture. It can show the presence of a distal radial fracture with volar angulation, the fracture location (extra-, juxta-, or intra-articular), the degree of angulation, and displacement. It can also comment on carpal malalignment, carpal fractures, and the articulation of the radio-lunate and radio-scaphoid joints. Additional radiographs of the wrist such as traction, oblique, and fossa lateral views may provide critical information about the associated soft tissue injuries.   

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CT Scan

In cases of comminuted or intra-articular fracture, a CT scan assists not only the pattern of injury but also helps the surgeon plan for a strategy for operative reduction.

Outcome Measures

The patient outcome can be assessed using several variables: X-rays, ROM, grip strength, pinch strength, and patient-rated functional outcome measures.

• Disabilities of the Arm, Shoulder (DASH) is a validated outcome measure that comprises a 30-question survey, with a lower score showing the better function.
• Michigan Hand Questionnaire (MHQ) measures outcomes using 6 scales including overall hand function, activities of daily living, pain, work performance, aesthetics, and satisfaction with hand function.

Management

Conservative

Treatment of a non-displaced and a stable Smith's fracture is by closed reduction and splint or cast. The closed reduction can be done under procedural sedation, hematoma block, regional nerve block, intravenous regional/Bier block, or general anesthesia. AAOS clinical guidelines suggest weekly radiographs for the first three weeks after reduction and immobilization and before the removal of splints. 

Patients can also be treated with closed reduction and percutaneous pinning for distal radius fractures using Kirschner wires. Pinning is an efficacious, low-cost treatment option for 2- and 3-part distal radius fractures with excellent long-term outcomes, however, it is not recommended in presence of poor bone quality and multiple fragments. Pinning may cause injury to the tendons, nerves, or vasculature, pin migration, fracture settling, and a pin site track infection.

Surgical

Indications for surgical management include:

1. Dorsal or volar comminution
2. Intra-articular involvement
3. Instability post-reduction
4. Surface angulation greater than 20 degrees
5. Articular surface step-off over 2 mm
6. Radial shortening greater than 5 mm

Open reduction internal fixation (ORIF) is the best option for treating an unstable or not reducible fracture. According to the American Academy of Orthopaedic Surgeons (AAOS) guidelines, volar plate internal fixation is recommended as it reduces the risk of extensor tendon rupture and also preserves the blood supply of the metaphysis.

Pain management in the postoperative period can be managed by discussing with the operative team and primary care. Research suggests transdermal buprenorphine and codeine-acetaminophen provided superior pain control than celecoxib in the six weeks following ORIF with a volar locking plate, thus citing better compliance and faster functional recovery, however, the use of opioid analgesics should be limited outside the acute management environment.

Physiotherapy

• Stable fractures are immobilized for 4 to 8 weeks followed by rehabilitation exercises and bracing another 4 to 6 weeks until pain-free ROM and have achieved normal strength.
• Unstable fractures are often immobilized for 6 to 12 weeks, followed by rehabilitation for regaining motion and strength.
• Pain management can be achieved with cryotherapy and elevation.
• AAOS 2009 Clinical Practice Guidelines recommend adjuvant treatment with vitamin D for the prevention of complex regional pain syndrome (CRPS) development following distal radius fractures (moderate level of recommendation).
• Preventive measures of distal radius fractures mainly revolve around fall prevention, which is especially relevant in the elderly population.

Prognosis

Research shows a closed reduction yields a good outcome in patients, with functional healing around six weeks. Low-level medical evidence is available for long-term outcomes of early postoperative mobilization. For athletes, stable fixation, edema management, early mobilization with rehabilitation, and functional bracing is essential for an early return to sports activity.