MANAGED. EVEN WITH GOOD CLINICAL SKILLS AND DIAGNOSTIC TESTS, AN ACCURATE DIAGNOSIS IS NOT ALWAYS POSSIBLE

Relationship to the wrist Several tendons, nerves and blood vessels cross the wrist, all of which can be injured or cause pain.

The following structures pass anterior to the flexor retinaculum (medial to lateral): n FCU tendon (which attaches to the pisiform bone) n Ulnar nerve n Ulnar artery n Palmaris longus tendon attaching to the flexor retinaculum and palmar aponeurosis n Palmar cutaneous branch of the median nerve n FCR

Structures passing beneath the flexor retinaculum (medial to lateral) n FDS and FDP (they share a common synovial sheath) n Median nerve n FPL.

The following structures pass posterior to the extensor retinaculum (medial to lateral): n Posterior cutaneous branch of the ulnar nerve n Superficial branch of radial nerve.

Structures passing beneath the extensor retinaculum include the fibrous septae from six compartments containing the extensor tendons. Each numbered compartment has a synovial sheath. From radial to ulnar, they are: 1. APL and EPB 2. ECRL and ECRB (posterior to the distal radio-ulnar joint) 3. EPL

4. ED and EI

5. EDM 6. ECU.

The radial artery passes between the first and second compartments.

INVESTIGATIONS X-rays Plain X-rays can confirm a bone or joint injury. However, a negative X-ray does not exclude a bony injury. A clenched-fist view may

demonstrate an acute scapho-lunate ligament rupture, with the gap widening as the joint is axially loaded. Scaphoid views should be taken if there is clinical suspicion of a scaphoid injury, and repeated 2 weeks later if still suspicious (by which time, fracture-line resorption and shift in the fracture’s position usually discloses the injury). Use a carpal tunnel view, with the wrist in dorsiflexion, if a hook of hamate fracture is suspected.

MAGNETIC RESONANCE IMAGING

Magnetic resonance imaging (MRI) is the most sensitive method of diagnosing an acute ligament or bone injury and has superseded isotope bone scanning for this purpose. In the non-acute setting when a TFCC or interosseous ligament tear is suspected, the accuracy is enhanced by intra-articular contrast (arthrography).

Computed tomography Computed tomography (CT) is the most specific method of identifying bone anatomy (which does not show so well on MRI). CT is best used to define cortical margins that are difficult to define on plain X-ray (eg. comminuted

WRIST INJURIES IN SPORT ARE OFTEN POORLY DIAGNOSED AND INADEQUATELY

fractures, hook of hamate fracture, displaced scaphoid fractures requiring fixation, declaration or otherwise of a healed scaphoid fracture). CT arthrography enhances accuracy.

Ultrasound

This is an excellent investigation to assess soft-tissue injuries, tendinopathies and superficial ganglia. It is cheap and can be used in an outpatient setting and can also be used dynamically. However, it is user- dependent.

Wrist arthroscopy This is a very valuable way of investigating the wrist, as most structures can be visualised and passive movements assessed.

ACUTE WRIST INJURIES These occur mainly from acute trauma, such as being hit by an object or falling on to an outstretched hand. There is also a proportion of athletes who injure their wrists in weight training, where poor technique or the use of weights that are too heavy leads to hyperextension injuries. This may be prevented or reduced by wearing appropriate prophylactic strapping in order to prevent hyperextension.

Common injuries n Fracture distal radius n Fracture scaphoid n Wrist “sprain” (a common eventual diagnosis – the exact cause can still be difficult to diagnose even after thorough investigation; it is therefore a diagnosis of exclusion) n Scapho-lunate sprain and other intercarpal ligament sprains n TFCC tear n Scapho-lunate tear n Bone bruising.

History

A clear history of the mechanism of injury may give a clue to the diagnosis (eg. a fall on an outstretched hand for a fractured scaphoid or forced ulnar deviation and rotation for a TFCC tear).

Inspection Look for swelling, bruising and deformity.

Palpation Feel systematically to assess each bone, joint and tendon for tenderness.

22 sportEX medicine 2009;41(Jul):21-26