Fractured Shaft of Humerus

Dr. D. N. Bid [PT]

Mechanism of injury

• A fall on the hand may twist the humerus, causing a spiral fracture.

• A fall on the elbow with the arm abducted exerts a bending force, resulting in an oblique or transverse fracture.

• A direct blow to the arm causes a fracture which is either transverse or comminuted.

• Fracture of the shaft in an elderly patient may be due to a metastasis.

Pathological anatomy

• With fractures above the deltoid insertion, the proximal fragment is adducted by pectoralis major.

• With fractures lower down, the proximal fragment is abducted by the deltoid.

• Injury to the radial nerve is common, though fortunately recovery is usual.

Clinical features

• The arm is painful, bruised and swollen.

• It is important to test for radial nerve function before and after treatment.

• This is best done by assessing active extension of the metacarpophalangeal joints;

active extension of the wrist can be misleading because extensor carpi radialis longus is sometimes supplied by a branch arising proximal to the injury.

X-ray

• The site of the fracture, its line (transverse, spiral or comminuted) and any displacement are readily seen.

• The possibility that the fracture may be pathological should be remembered.

Treatment• Fractures of the humerus heal readily.

• They require neither perfect reduction nor immobilization; the weight of the arm with an external cast is usually enough to pull the fragments into alignment.

• A ‘hanging cast’ is applied from shoulder to wrist with the elbow flexed 90 degrees, and the forearm section is suspended by a sling around the patient’s neck.

• This cast may be replaced after 2–3 weeks by a short (shoulder to elbow) cast or a functional polypropylene brace which is worn for a further 6 weeks.

• The wrist and fingers are exercised from the start.

• Pendulum exercises of the shoulder are begun within a week, but active abduction is postponed until the fracture has united (about 6 weeks for spiral fractures but often twice as long for other types);

• once united, only a sling is needed until the fracture is consolidated.

• OPERATIVE TREATMENT• Patients often find the hanging cast

uncomfortable, tedious and frustrating; • they can feel the fragments moving and that is

sometimes quite distressing.

• The temptation is to ‘do something’, and the ‘something’ usually means an operation.

• It is well to remember:– (a) that the complication rate after internal

fixation of the humerus is high and – (b) that the great majority of humeral fractures

unite with non-operative treatment.– (c) There is no good evidence that the union rate

is higher with fixation (and the rate may be lower if there is distraction with nailing or periosteal stripping with plating).

• There are, nevertheless, some well defined indications for surgery:• severe multiple injuries• an open fracture• segmental fractures• displaced intra-articular extension of the fracture• a pathological fracture• a ‘floating elbow’ (simultaneous unstable humeral and forearm fractures)• radial nerve palsy after manipulation• non-union• problems with nursing care in a dependent person.

• Fixation can be achieved with either :– (1) a compression plate and screws, – (2) an interlocking intramedullary nail or semi-

flexible pins, or – (3) an external fixator.

• Plating permits excellent reduction and fixation, and has the added advantage that it does not interfere with shoulder or elbow function.

• However, it requires wide dissection and the radial nerve must be protected.

• Too much periosteal stripping or inadequate fixation will probably increase the risk of non-union.

• Antegrade nailing is performed with a rigid inter-locking nail inserted through the rotator cuff under fluoroscopic control.

• It requires minimal dissection but has the disadvantage that it causes rotator cuff problems in a significant proportion of cases (the reported incidence ranges from 5–40 per cent).

• The nail can also distract the fracture which will inhibit union; if this happens, exchange nailing and bone grafting of the fracture may be needed.

• Retrograde nailing with multiple flexible rods is not entirely stable. Retrograde nailing with an interlocking nail is suitable for some fractures of the middle third.

• External fixation may be the best option for high-energy segmental fractures and open fractures.

• However, great care must be taken in placing the pins as the radial nerve is vulnerable.

Complications

• EARLY• Vascular injury • If there are signs of vascular insufficiency in the

limb, brachial artery damage must be excluded. • Angiography will show the level of the injury. • This is an emergency, requiring exploration and

either direct repair or grafting of the vessel. • In these circumstances, internal fixation is

advisable.

• Nerve injury • Radial nerve palsy (wrist drop and paralysis of the

metacarpophalangeal extensors) may occur with shaft fractures, particularly oblique fractures at the junction of the middle and distal thirds of the bone (Holstein–Lewis fracture).

• If nerve function was intact before manipulation but is defective afterwards, it must be assumed that the nerve has been snagged and surgical exploration is necessary.

• Otherwise, in closed injuries the nerve is very seldom divided, so there is no hurry to operate as it will usually recover.

• The wrist and hand must be regularly moved through a full passive range of movement to preserve joint motion until the nerve recovers.

• If there is no sign of recovery by 12 weeks, the nerve should be explored.

• It may just need a neurolysis, but if there is loss of continuity of normal-looking nerve then a graft is needed.

• The results are often satisfactory but, if necessary, function can be largely restored by tendon transfers (see Chapter 11).

• LATE• Delayed union and non-union : Transverse fractures

sometimes take months to unite, especially if excessive traction has been used (a hanging cast must not be too heavy).

• Simple adjustments in technique may solve the problem; as long as there are signs of callus formation it is worth persevering with non-operative treatment, but remember to keep the shoulder moving.

• The rate of non-union in conservatively treated low-energy fractures is less than 3 %.

• Segmental high energy fractures and open fractures are more prone to both delayed union and non-union.

• Intramedullary nailing may contribute to delayed union, but if rigid fixation can be maintained (if necessary by exchange nailing) the rate of non-union can probably be kept below 10 per cent.

• A particularly vicious combination is incomplete union and a stiff joint.

• If elbow or shoulder movements are forced before consolidation of the fracture, or if an intramedullary nail is removed too soon (e.g., because of shoulder problems), the humerus may re-fracture and non-union is then more likely.

• The treatment of established non-union is operative.

• The bone ends are freshened, cancellous bone graft is packed around them and the reduction is held with an intramedullary nail or a compression plate.

• Joint stiffness • Joint stiffness is common. It can be minimized by early

activity, but transverse fractures (in which shoulder abduction is ill-advised) may limit shoulder movement for several weeks.

SPECIAL FEATURES IN CHILDREN

• Fractures of the humerus are uncommon; in children under 3 years of age the possibility of child abuse should be considered and tactful examination for other injuries performed.

• Taking advantage of the robust periosteum and the power of rapid healing in children, the humeral fracture can usually be treated by applying a collar and cuff bandage for 3 or 4 weeks.

• If there is gross shortening, manipulation may be needed.

• Older children may require a short plaster splint.

Thank you…………..