Scaphoid Fractures

The scaphoid is the most frequently fractured (broken) carpal bone in the wrist.

Pathology

The scaphoid is the most frequently fractured carpal bone in the wrist. This fracture is often the result of a fall from ground level with the wrist hyperextended and turned towards the thumb (radially deviated).

In lower energy injuries, patients with a scaphoid fracture may have minimal discomfort with no swelling. Furthermore, the fracture of the scaphoid when initially undisplaced is often times not visible on a plain x-ray. In this low energy presentation, the fracture is often misdiagnosed as a wrist sprain unless a high index of suspicion is present by the clinician. If a scaphoid fracture is missed and the wrist is not immobilized, a nonunion will develop, which is difficult to treat.

In higher energy injuries, such as a fall from a height, a sports injury, or a motor vehicle accident, the fracture and ligamentous injuries are more obvious. Patients with a scaphoid fracture may complain of thumb sided wrist pain, decreased range of motion of the wrist, swelling and weakness and on exam will demonstrate tenderness in an area of the wrist called the “snuff box”.

The scaphoid receives little blood supply and often fails to heal in 13- 50% of fractures. This percentage increases in fractures of the scaphoid involving the proximal pole. Due to the limited blood supply, scaphoid fractures have a prolonged healing time, ranging from nine months to one year for confirmed healing.

When a scaphoid fracture does not heal, it will progress to scaphoid collapse and progressive wrist arthritis. Treating a scaphoid fracture that doesn’t heal is very challenging and therefore an accurate diagnosis and timely treatment is preferable.

Treatment

Plain X-rays are initially obtained when suspicion of a scaphoid fracture exists after a wrist injury. Classically, patientswith clinical findings of a scaphoid fracture but normal x rays findings are still treated with immobilization in a cast. They are re-evaluated in two weeks with repeat x-rays because it takes time for the fracture line to appear on x-ray film when it is non-displaced.

If a physician has a high index of suspicion that a scaphoid fracture is present and immediate surgical intervention is the preferred method of treatment, an MRI (Magnetic Resonance Imaging) can be obtained.

An MRI will detect all occult fractures and is the gold standard when an early scaphoid fracture diagnosis is desired. A scaphoid fracture that is not displaced can be treated in a cast or fixed surgically with a screw.

If treated in a cast, it takes at least 12 weeks of continuous immobilization followed by a removable splint and frequent x-rays to assure the fracture healing is progressing in the correct direction. Patients may experience significant stiffness and weakness after such a prolonged period of wrist immobilization.

Surgical treatment consists in the application of specially designed headless screws that create stable fixation of the fracture. Surgical treatment has been reported to improve union rates to 95% or higher for all types of scaphoid fractures, improve the wrist range of motion and shortens the healing time.

Almost all proximal pole fractures and all displaced scaphoid fractures are best treated with surgery. Once surgically fixed, patients can be protected with a removable brace. The brace allows for early gentle hand and wrist activities while facilitating hygiene.

A therapy program may be necessary depending on the type of treatment selected and the patient’s limitations found after the fracture has healed.