Many principles governing bone healing in civilian blunt trauma do not apply to war wounds and therefore treatment differs.*
*Beware of the 'expert' who has no experience of war wounds!
Immaculate reduction and primary bone healing are rarely possible; the comminuted nature of the fractures forces the surgeon to rely on secondary or periosteal bone healing (callus formation) to heal the fractures.
The excisional aspect of the surgery of bone wounds is particularly important. Loose bone fragments, haematoma and surrounding dead tissues must all be removed to produce a well-vascularized environment that is conducive to callus formation. The method of fracture fixation is of secondary importance to the wound management. A potent stimulator of secondary bone formation is multiaxial movement of the fracture; neither the extent of movement required nor its mechanism of osteoblastic stimulation is fully understood. However, the surest way to eliminate secondary bone healing of the war-injured long bone is to ignore the wound complex and to fix the fracture rigidly. Sadly, this is common where external fixation is widely used by unsupervised surgeons who are unfamiliar with the technique and unfamiliar with war wounds. Immobilization is important in the initial management of limb wounds; rigid fixation is not.
Equipment for internal fixation should not be made available for early management of war wounds; it is readily abused, with disastrous results.
For any wound with a fracture, the advantages and disadvantages of each method of immobilization should be considered. Any method, if badly applied or unsupervised, can lead to poor results.
• Good access to the soft tissue wound (cases 4 and 10).
• Early mobilization of the patient and joints adjacent to the fracture.
• Reducing the gap between bone ends is possible if limb shortening is acceptable.
• Delay in callus formation (Fig. 3.1). (This can be avoided by early movement of the fracture within the first 2 weeks.)
• Incorrect placing of pins causing stiff joints, muscle tethering with prolonged swelling, nerve palsies and pain.
• Pin-site infection.
• The surgical time used in application.
Figure 3.1 Radiograph of the right thigh of a child of 11 years. He had been wounded 2 months beforehand. External fixation was applied at the time of wound excision. Note: the lack of callus crossing the fracture; callus production in response to infection of the second pin from the top; lucency of the bone around this pin indicating that it is infected and loose.
External fixation is not the best way to treat all fractures in war surgery. Very good results can be achieved with external fixation when it is correctly applied for the correct indications. The surgeon should recognize that, for some wounds, its disadvantages outweigh the advantages.*
*No other subject brings out rigid beliefs like external fixation.
When the surgeon is able to achieve early wound closure the advantages relating to wound access are minimized.
External fixation does not need to be applied as an emergency procedure. It is easier at the same time as delayed closure. The small movement of the fracture in the period between wound excision and rigid fixation may help stimulate callus. (This is a controversial view.)
The surgeon must be familiar with the equipment before starting the operation.
For the pins, the skin should be incised with a scalpel, making sure there is no tension.
A guide must be used when drilling bone.
The pins should not be inserted:
• nearer than 2 cm to a joint
• nearer than 2 cm to the fracture
• through the soft tissue wound
• into one cortex only
There should be at least two pins either side of the fracture, placed as far apart as possible.
On the leg, the pins should be placed in the anteromedial, subcutaneous part of the tibia.
On the thigh, the pins should be placed posterolaterally, so avoiding tethering of the quadriceps. Placing the lowest pins with the knee flexed to 90° helps later knee mobilization.
On the forearm, the pins should be placed laterally into the radius or into the subcutaneous border of the ulna.
A nerve palsy should be recorded before applying the external fixator (especially the radial nerve in humerus fractures).
The pins of the external fixation should not be used as a form of internal fixation.
Intrafragmentary compression of the pins may prevent pin loosening at a later date.
Interfragmentary compression can reduce the bone gap in a comminuted fracture with bone loss; the patient's disability increases with the degree of shortening.
A surgeon who is unfamiliar with the technique of external fixation is advised to begin by applying it for tibial fractures only; here it is easier and the complications are less.
It is not clear whether external fixation permits primary bone healing in fractures without bone loss (F1 fractures). To do so the frame must be absolutely rigid and must compress the fracture.
The use of external fixation across joints is considered below.
Factors which weigh in favour of the use of external fixation
• Multiple limb injuries, e.g. amputation of one leg and a tibial fracture in the other.
• A fracture and a vascular injury (the only indication for emergency application).
• A wound so large with the limb so unstable that external fixation is the only means to hold the limb in a reasonable position (Fig. 3.2); this is often the case with severe injuries of the knee or elbow, in which case the fixator must cross the joint.
• The need to transport the patient; this usually only applies to wounds of the thigh with femoral fractures.
Figure 3.2 Photograph of a young woman's thigh taken at the first dressing change in the operating theatre. She had been injured by a shell fragment and had wound excision on admission; the limb had been immobilized in skeletal traction. At the time the photograph was taken, after 4 days, the large wound was heavily infected and the remaining dead tissue was excised. It was then discovered that the shell fragment had passed through the thigh and then into the pelvis; faeces were fistulating into the vagina so contaminating a smaller wound on the medial side of the thigh. It was decided to apply the external fixator as shown because of the degree of tissue loss and because a prolonged period of ward dressing was foreseen. Laparotomy and sigmoid loop colostomy were also performed. She had a protracted hospital stay which included bone grafts of the femur and repair of the rectovaginal fistula. She was eventually discharged with a solid femur.
Factors which weigh against the use of external fixation
• Wounds in children.
• Wounds with no fracture.
• Closed fractures.
• When either one of the forearm or leg bones has a fracture but the other is intact.
• Absence of radiography.
• Lack of surgical follow-up.
Aftercare of external fixation
Pin-site problems are common; however, the pin only needs to be removed if there is evidence of infection at the pin - bone interface (pin loosening or lucency around the pin on radiography - Fig. 3.1). Soft tissue infection may respond to antibiotics and drainage. One should not confuse infection with allergy to an antiseptic used to clean around the pins.
Correct physiotherapy for a patient with an external fixator includes active and passive joint movement, appropriate weight bearing as soon as possible and mobilization with walking aids. The patient will not do this without encouragement and assistance.
It is difficult to know when to remove a fixator, especially if callus formation is slow. As a general rule the fixator should be removed as soon as the soft tissue wound is healed and then, if necessary, the limb can be put into a plaster of Paris cylinder. There may be advantages from the point of view of mobility to leave a femur fixator long after skin closure; 4 or 5 months may pass before there is enough bone healing to permit walking with crutches.
Removal of an external fixator may be very painful; it should be carried out under anaesthesia. The stability of the fracture can be checked by disconnecting the bar; if this is satisfactory, the pins can then be removed.
• Rapid callus formation (Fig. 3.3)
• Wound access can be difficult
• The patient is confined to bed for a long period
• Malunion occurs if the traction is not carefully supervised
Figure 3.3 (a) Radiograph of an adult's right thigh wounded by a bullet. There is a comminuted fracture (F2). The wound was 8 days old; the patient had wound excision and subsequent closure by secondary intention. The limb was immobilized by skeletal traction.
For femur fractures (case 2)
This can be effectively and most simply applied on a frame or in a split bed. A design for a traction frame which can be used for femur or tibial fractures is shown in Figure 3.4.
The pin is best applied to the tibial condyle. A supracondylar femoral pin is more painful as it pierces the quadriceps muscle and the iliotibial tract. It may then hinder knee mobilization.
In penetrating trauma, overlapping fractures rarely occur; many of the muscles have been damaged or divided by the missile and so their spasm does not have to be overcome. There is no need for the weight of traction to exceed 10% of the body weight initially; this can be reduced after 10-14 days.
Figure 3.3 (b) Radiograph of the same thigh taken after 5 weeks. Note the abundant callus formation. The patient was mobilized on crutches at this time.
The fracture should be so padded that the natural forward bow of the femur is exaggerated. If this is not done the fracture will sag into the traction frame and malunion will occur. If the patient has to be moved for follow-up radiography and care is not taken, the position of the fracture on the radiograph may not be representative.
The hip can be flexed by sitting the patient up and the knee flexed by dropping the leg, in traction, through the traction frame or split bed.
When the fracture is clinically solid and there is adequate callus formation on the radiograph, the traction can be removed (usually 4-6 weeks in a young patient).
Figure 3.4 (a) The design of a traction frame suitable for most lower limb wounds. It can be manufactured from a variety of materials.
Figure 3.4 (b) The bandaging gives a safe and comfortable base for the limb. The exact dimensions are given on the diagram
Figure 3.4 (c). It is possible to alter the direction of the traction by using the separate pulley attachment. Note that the frame is narrower where the upper thigh rests; this ensures that the corner of the frame does not press into the other thigh. (Frame designed by François Cappus and Daniel Odhiambo, physiotherapists in the ICRC hospital at Lokichokio, Kenya.)
(d) Photograph of a patient in the traction frame. Note that his heel is free of compression, the fracture is supported by extra padding and that the direction of pull of the traction is slightly below the line of the femur. This prevents sagging of the fracture into the frame.
(e) The patient receiving physiotherapy. Note that the leg portion of the frame bandage is removed to ensure that the knee can be flexed.
For tibial fractures
The pin should be placed through the calcaneus.
No more than 5 kg is required.
A plaster of Paris splint may also be necessary to prevent rotation of the foot (and therefore the fracture).
The patient should be moved into a full plaster of Paris as soon as possible and mobilized out of bed.
It is very difficult to mobilize the knee and ankle in calcaneal traction.
Plaster of Paris (cylinders (circular) or splints)
• Good patient mobility
• Rapid callus formation
• Poor wound access
• No mobility of the joints adjacent to the fracture
• Unsuitable for proximal limb fractures
Plaster of Paris splints
The application of a plaster splint, either as a single strip or as multiple strips, is a quick and effective means of immobilization of a limb, e.g. a U-splint for the humerus or a dorsal splint combined with a U-splint for the tibia.
The splint should be well-padded, especially over the heel, and applied outside the bulky wound dressing.
Neither the splint nor the over-bandaging should be constrictive.
The splint should incorporate the joint above and the joint below a fracture. The knee joint should be immobilized at 45° of flexion; the ankle in dorsiflexion; the elbow at 45° of flexion and in mid-pronation; the wrist in dorsiflexion.
A difficult limb wound can be managed with a series of splints being applied at the stages of wound surgery (case 1). This is only effective if the wound excision is complete (and therefore there is little need for frequent dressings and wound closure is rapid).
Plaster of Paris cylinders
These should not be used immediately after primary surgery. The limb is usually transferred to a plaster cylinder after a series of splints or external skeletal fixation. The plaster cylinder can be moulded as a cast brace to permit weight bearing.
The cylinders must be well-padded, especially over the heel.
On the lower limb, weight bearing should begin as soon as possible.
A plaster cylinder can have a window cut to dress a wound; however, the wound edges frequently swell and bulge out of the window. If the wound is clean there is no need for regular dressing changes and so the window may not be necessary. An extension of this principle is that a clean open wound can be left under a plaster undisturbed; this closed plaster technique (after Trueta) can be particularly useful with difficult wounds around the ankle.