Fracture Handbook

  

1. Finger Metacarpals

 

1.1. Metacarpal Base (Extra-articular)


The two halves of the broken bones (fracture) are typically only mildly tipped or separated (displaced) and do well with early movement. If the two halves of the broken bone are markedly separated (displaced) the surgery is usually needed. This may be performed under local anaesthetic but typically is performed under general anaesthetic. Usually the fracture does not need to be opened up. Rather the main fragment can be pushed into place (manipulated) and held with 1-3 wires passed through the skin known as K wires. These usually protrude through the skin so they can easily be removed in the outpatient's clinic. Some surgeons will bury the wire under the skin. Then a further operation is needed usually under local anaesthetic. The wires typically remain in place for 4-5 weeks. During this time the fracture and wires will need support in a plaster cast either a full cast or a partial cast. Any fingers or parts of fingers not held by the plaster should be moved to reduce stiffness. Most patients do very well following these injuries.

 

1.2. Metacarpal Base (Intra-articular) including fracture/dislocations

This break (fracture) typically affects the ring finger (RF) or the little finger (LF). These are due to a high energy injury such as a fall or a punch. The can just give a dislocation of the joint at the bottom of the metacarpal without a fracture. This joint is called the carpometacarpal joint (CMC joints).

All dislocations or fracture dislocations should to be put back in joint (reduced) and held in joint until healed. Sometimes the injury will pop back into joint and be stable enough to hold in a plaster cast. If so they need careful supervision with repeat X-rays for 2-3 weeks from injury to make sure they do not slip out again. If the joint is not that stable it will need to be held with 1-3 wires passed through the skin known as K wires. These usually protrude through the skin so they can easily be removed in the outpatient's clinic. Some surgeons will bury the wires under the skin. Then a further operation is needed usually under local anaesthetic.
Only occasionally is open surgery required i.e. a formal cut is made on the back of the hand over the injury.
The wires typically remain in place for 4-5 weeks. During this time the fracture and wires will need support in a plaster cast either a full cast or a partial cast. Any fingers or parts of fingers not held by the plaster should be moved to reduce stiffness. Most patients do very well following these injuries. Inevitably there will be long-term X-ray changes of arthritis in the injured joint but most people do not develop problems from this.


1.3. Metacarpal Shaft (middle of the bone)

(A) Transverse / Short oblique
Fractures of the middles of the bone (shaft) typically affect the little finger, sometimes the ring finger, and rarely all four fingers. Because of the long lever arm i.e. there are big fragments of bone either side of the break, these can often be pushed straight and held in a plaster cast for 4 weeks. The position should be checked weekly for at least 2 weeks to ensure the position of the fracture does not slip. The bones generally heal well with excellent hand function but there may be a residual bump in the middle of the bone if it heals with a slight angle. This does not prevent excellent function and is usually of minimal concern to patients.

If the fracture is off-ended i.e the fragments completely separated it may not go straight enough to hold in a plaster cast. In that case, it will require pushing under an anaesthetic in an operating theatre and held in place with 1-3 wires passed through the skin known as K wires. These usually protrude through the skin so they can easily be removed in the outpatient's clinic. Some surgeons will bury the wires under the skin. Then a further operation is needed usually under local anaesthetic.
The wires typically remain in place for 4-5 weeks. During this time the fracture and wires will need support in a plaster cast either a full cast or a partial cast. Any fingers or parts of fingers not held by the plaster should be moved to reduce stiffness. Most patients do very well following these injuies.
Some surgeons favour open surgery using plate and screws but this increases the risks for little extra reward so we try to avoid it.

B) Spiral / Long oblique
Twisting injuries can lead to spiral fractures of the metacarpal bones. A fall can lead to a long break line known as a long oblique fracture. Our research has shown that the best treatment for these injuries if early movement. The bone fragments heal with a little overlap giving slight shortening of the finger - typically only 2-5 mm. This is of almost no cosmetic concern. Early movement allows early return to work and sport and almost always results in full and painless movement.

 

1.4. Metacarpal Neck (Extra-articular)

This injury is very common. It is usually caused by a punch and is known as a ‘boxer's' fracture. The injury typically occurs in the little and sometimes the ring finger. A tilt at the break of even up to 70° is well tolerated, although at > 50°, often a push (manipulation) can reduce the angle of the break (angulation) in part and is recommended. For lesser angulations patients are best treated with early movement, ensuring they make a full fist early. There may be lack of full straightening of the finger at the knuckle joint for 2-4 weeks and there will be a long-term dropped knuckle but typically these injuries result in an excellent outcome.


1.5. Metacarpal Head (into the joint)


These are typically a longitudinal split. Usually most of the metacarpal head is fine i.e. not broken and attached to the rest of the bone. The small bit that is broken is off to the side and fortunately this is a joint that will tolerate some mal-alignment out to the side i.e. not quite perfect healing. Surgery is therefore not typically needed. These fractures may however be unstable and need to be protected in a plaster cast and watched for at least 2 weeks from injury with further X-rays. Physiotherapy is usually required after 3 weeks, and there will often be some joint stiffness long-term.
If there is a significant step or gap of more than 1 - 2 mm, in the mid part of the joint open surgery is recommended. The joint is opened from the back of the hand. The broken bones are aligned correctly and fixed with screws or wires. This is not an easy operation. There is often some remaining malalignment of the fragments i.e. they are not put back together perfectly as it is so difficult and typically some long-term joint stiffness.

 

1.6. Metacarpal Head (Contaminated open injury)


This injury is almost always sustained by a punch with the opponent's tooth penetrating the joint. There will often be a cut over the knuckle (metacarpal head). The injury occurs with the finger but the patient often comes up with the finger less bent for comfort. The cut in the joint lining (capsule) will therefore not be in line with the skin cut and so it will look like the injury has not gone into the joint.
All of these injuries should be explored thoroughly under local anaesthetic, even if only in A & E. If a track down to the joint is found the patient should receive formal and urgent exploration and washout in an operating theatre.
These injuries should ideally be operated upon on the night of injury. If it is not possible to get in to theatre that acutely, at the very least a local anaesthetic washout should be undertaken in the A & E Department. The patient will need come into hospital, be given antibiotics into their veins and possibly cover for tetanus. There is typically a divot out of the joint surface that may not show on X-rays. This usually does not need fixation, as it is stable.
In severe injuries the washout in the operating theatre may need to be repeated but that is very uncommon in our experience.
Most patients do very well but if there is delay and infection becomes established the joint surfaces may be destroyed. This often leads to a stiff and sometimes painful joint that may require later reconstructive surgery such as a joint replacement.

 

 
 

The Hand to Elbow Clinic
29a James Street West
Bath BA1 2BT

Tel 01225 316895
Fax 01225 484949
info@handtoelbow.com
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