Injuries

Vascular injuries

Vessel division

A partial injury of an artery will not contract and seal itself so it continues to bleed. Bleeding should be controlled with pressure — it is dangerous to use a tourniquet (which can be forgotten) or to clip the vessel blindly (which spoils the chance for repair and can damage the nearby nerve).

Compartment syndrome

Following crush injuries and fractures of the forearm or hand, or prolonged ischaemia from vessel damage, tourniquet or tight dressings, a compartment syndrome can develop. The pressure within the fascial compartments (superficial flexor, deep flexor, extensor, interossei, thenar and hypothenar) rises and occludes the microcirculation which supplies the muscles and nerves. The symptoms are pain, tingling, cold; the signs are tightness, tenderness and swelling of the muscles, and pain on passive stretching of the muscles in the compartment. The main vessels will not necessarily he occluded as their closing pressure is greater than the pressure required to cut off the microcirculation. Any cast and dressings should be released and, if this does not relieve the ischaemia, then a surgical fasciotomy should be performed. Measurement of the compartment pressures can help in a few cases, but should not delay fasciotomy if the clinical picture is clear.

Fractures

Scaphoid

This bone is fractured by a fall on the outstretched hand. The fracture is easily overlooked — it causes little deformity or pain and does not always show clearly on plain radiographs. However, it is notorious for two reasons — it may not unite (par­ticularly in the relatively avascular proximal pole) or it may present later with intercarpal collapse and osteoarthritis. If there is doubt about the diagnosis, the wrist is best immobilised and radiographs repeated 2 weeks later. If there is still doubt, isotope bone scanning or MRI scanning will confirm the diag­nosis. Plaster immobilisation is needed for at least 8 weeks; delayed union (e.g. if not healed by about 3 months) may merit bone graft and internal fixation (Fig. 30.6). Some unstable displaced fractures probably need early internal fixation.

Distal radius

This is commonly injured. There are broadly three groups of fracture.

  Children. Usually a Salter Harris type 2 physeal injury, with the distal ulna sometimes fractured as well. Manipulation and plaster fixation for a few weeks is usually ade­quate. Percutaneous Kirschner wires are sometimes needed for unstable injuries.

  Young adults. Usually a high-energy injury, with several intra-articular fragments. Perfect anatomical reduction is most likely to give the best result; this may need a selection of techniques, including bone graft, percutaneous wires, internal fixation and distraction with an external fixator.

  Older adults. Typically through osteoporotic bone in a postmenopausal female after a fairly minor fall. This is the classic Colles’ fracture. The distal fragment is tilted dorsally and radially; the radius is shortened because of impaction. Reduction is easily achieved by manipulation under regional anaesthesia or haematoma block, but slippage is common and percutaneous wires may be chosen for some.

Metacarpals and phalanges

 

  Fifth metacarpal neck: usually caused by a punch (hence Boxer’s fracture’). Up to 600 of flexion at the fracture site can be accepted because of the spare hyperextension in the fifth metacarpophalangeal joint and because the little finger’s function is to flex — a loss of extension is not functionally too important. It is treated with elevation and splintage for a few days and then gentle mobilisation. Sur­gery is rarely required. The ‘dropped knuckle’ deformity is permanent.

       Metacarpal shaft fractures: most metacarpal fractures are stable and undis placed, and need a resting splint for 1—2 weeks followed by careful mobilisation. If spiral, the finger rotates (no longer points to the scaphoid tubercle along with the other fingers when flexed into the palm); if angulated the prominent metacarpal head can be uncomfortable when gripping. Therefore some metacarpal fractures need manipulation and fixation with plates or percutaneous Kirschner wires.

  Phalangeal fractures: whatever the fracture and its management, the fingers must be moved within a few days of injury to avoid stiffness. Most phalangeal fractures are undisplaced or can be manipulated under local anaesthetic into a stable, anatomical position. The hand is splinted and elevated for a few days then the fractured finger is strapped to a neighbouring finger and mobilised. If the fracture is displaced and unstable, or if the joint surface is disrupted, accurate reduction and fixation is needed. Rigid fixation with miniplates and screws allows early mobilisation which prevents stiffness, but unfortunately the soft-tissue dissection required paradoxically can cause stiffness. Therefore, percutaneous wires are generally preferred unless open surgery is needed for reduction.

Ligaments

Carpal instability

No tendons attach to the scaphoid, lunate or triquetral. These bones are called the ‘intercalated segment’, and their position and stability are controlled by the stout ligaments interconnecting them. Damage to these ligaments, usually after a fall on the outstretched hand, causes the bones to rotate abnormally in relation to each other (Fig. 30.7). If the scapholunate ligament is ruptured, the lunate tilts dorsally and the scaphoid flexes forward; on the posteroanterior radiograph the flexed scaphoid looks like a ‘ring’ and the scapholunate gap opens up. Early repair and temporary stabilisation with wires should be considered.

Thumb ulnar collateral ligament

The ulnar collateral ligament of the thumb metacarpophalangeal joint is crucial for stable pinch. It can be torn when the thumb is wrenched radially (~skier’s thumb’). A relatively stable sprain is splinted for about 3 weeks; an unstable ligament should be repaired; often the adductor pollicis tendon is trapped between the torn ligament and its insertion. The thumb ulnar collateral ligament can also be stretched with chronic overuse (‘gamekeeper’s thumb’).

Triangular fibrocartilage complex

This important structure attaches the base of the ulnar styloid to the ulnar side of the distal radius. It is continuous with the dorsal and palmar capsule of the ulnar side of the wrist. The TFCC stabilises the distal radioulnar joint. It can be torn, leading to instability of the distal radioulnar joint and ulnar sided wrist pain. The diagnosis is confirmed by arthrography or arthroscopy, and some tears can be repaired.

Dislocations

Peri lunate

A fall on the outstretched hand can cause the lunate to dislocate from the surrounding carpus, or for the carpus to dislocate around the lunate. The scaphoid may also be fractured. Median nerve compression may result. The injury is easily missed on radiographs. Prompt reduction should be supplemented by ligament repair and temporary Kirschner wires.

Metacarpophalangeal joints

These can be simple, which reduce easily, or complex, which usually need open reduction through a dorsal approach because the palmar plate (the thickened palmar capsule) is wedged in the joint.

Bennett’s fracture-dislocation

This unstable intra-articular fracture of the thumb carpometacarpal joint is difficult to treat with plaster; closed reduction and percutaneous wire fixation for 5 weeks is more reliable.

Interphalangeal joints

These are usually easy to reduce and are stable. However, an associated fracture of the condyles, tendon avulsion, palmar plate avulsion or collateral ligament tear may need specific treatment.

Tendons

Mallet finger

Forced flexion of the distal interphalangeal joint can rupture the insertion of the long extensor tendon. There may be a bone fragment. Closed reduction and splintage in full exten­sion for 8 weeks is preferable to surgery which has a high complication rate.

Flexor tendons

Flexor tendon injuries have a poor reputation. Surgery is particularly demanding in Bunnell’s ‘no man’s land’ — other­wise known as zone II — between the metacarpophalangeal joint and distal interphalangeal joint where both flexor digitorum superficialis and flexor digitorum profundus run in an intricate, tight fibrous sheath (Fig. 30.8). The best outcome is probably with primary repair by an experienced surgeon using special sutures under magnification (Fig. 30.9). Rehabilitation must be meticulous to avoid either stiffness or rupture. Various splints and mobilisation protocols have been recommended.

Extensor tendons

Extensor tendon injuries generally have a better outcome than flexor tendon injuries. They usually recover well with careful primary suture and splintage for about 4 weeks. There are two sites where special care must be taken.

 

  Cuts over the proximal interphalangeal joint, if untreated, can lead to a ‘boutonniere’ (buttonhole) deformity because the central slip no longer extends the proximal joint whilst the remaining extensor mechanism hyperextends the distal joint and flexes the .proximal joint. Early repair and splin­tage is therefore important.

  Cuts over the metacarpophalangeal joint, especially following a punch, usually enter the joint and must be thoroughly cleaned.

Fingertip injuries

The choice of treatment depends on the type of injury, as well as the patient’s occupation, hobbies and cosmetic demands. Many fingertip injuries will heal when left alone beneath a semi permeable dressing. If more than 1 cm2 of skin is lost, a skin graft will speed up the overall time to healing. If the pulp is lost and bone exposed then many techniques are available to cover the bone and maintain the length of the finger. If early return to manual work is important, then shortening through the distal interphalangeal joint is considered (‘terminalisation’). Careful attention to detail is important —trimming the condyles, tailoring well-vascularised skin flaps, burying the nerve ends and completely removing the nail bed. If length, sensation and appearance are important (particularly in the thumb and index finger) then a flap may be preferred: for example, a cross-finger flap or a V to Y advancement flap (Fig. 30.10).

Replantation

With microsurgical techniques, it is sometimes both possible and advisable to replant amputated parts (Fig. 30.11). Amputated parts should be wrapped in a sterile cloth soaked in sterile saline, and placed in a plastic bag which is placed in water and crushed ice. Replantation is not always advisable. The choice must always be tailored to the individual injury and the individual patient. A single digit replanted proximal to the superficialis insertion is likely to become very stiff, with imperfect sensation and the prospect of a considerable time off work after the first, and often subsequent, surgery. Amputation is often a better option. The thumb, in contrast, functions well enough even if stiff, and replantation should be considered.

Replantation

Indications:

Thumb

Single digits in children

Single digits at distal interphalangeal joint level

Multiple digits

Hand, wrist, forearm

  Relative contraindications:

Single digits in adults

Crushed, mangled or avulsed parts

Poor general condition of patient

Long warm ischaemic time