Once the fracture has been reduced and fixed, it becomes possible to make a proper assessment of the soft tissue component of the injury, and carry out an initial excision of irreparably damaged tissue, skin, fascia and muscle. The criteria for assessing viability of skin have already been described, and the excision of damaged fascia can safely be radical, since the muscle surface exposed will accept a graft.
Excision of fascia may also have the beneficial effect of decompressing muscle swollen and oedematous as a result of the injury. The only structure, vessels and nerves apart, which should be managed conservatively throughout is, as already stressed, periosteum. Even at this early stage, some idea of the reconstruction likely to be required is usually possible, and a provisional strategy can be drawn up.
If skin grafting is considered feasible, it is not obligatory to apply the graft there and then. There is much to be said for a ‘second look’, with a further debridement in order to improve the surface. Carried out 2-3 days later, the further debridement should leave only viable soft tissue exposed, and definitive decisions regarding reconstruction can be made.
When a skin graft is used after such a delay, the ultimate healing time may actually be reduced, with take of the graft becoming 100%, rather than being patchy.
The decision regarding the best form of skin
cover will depend very much on the site of the injury, the state of the bone, and the surface it presents. This, in turn, may well depend on the type of fracture, whether it is comminuted or not, and the estimated viability of any detached fragments.
The site most often involved by such a mixed injury is the lower half of the tibia, and in that site, if a reconstruction requires more than merely a free skin graft, the most effective alternative is likely to be a free flap, and the greater the deficiency in depth the more valuable will be the muscle component of the free flap. This aspect might determine whether or not a latissimus dorsi or rectus abdominis muscle flap is chosen.
The timing of free flap reconstructions remains
controversial -whether they should be carried out at the acute stage or postponed for a few days. The advocates of definitive free flap reconstruction at the acute stage tend to be enthusiasts for the method, but for most plastic surgeons the more severe forms of these mixed injuries are infrequent, and the results claimed for ‘acute’ free flap transfers are not necessarily repeatable by the occasional operator, who perhaps should be more cautious.
What can be stated with certainty is that, if the decision is made to use an immediate or even a delayed primary free flap, the debridement which immediately precedes the application of the flap should be more than usually thorough, making sure that no non-viable tissue is left to provide a focus of potential infection.
In managing these injuries, the question must
arise at some stage whether or not a damaged lower leg and foot is salvageable.
The question is not whether the limb can be preserved viable, but whether the result will be a useful functioning limb. Severely injured lower limbs are salvaged today in a manner which would
have been inconceivable until comparatively recently, and this is extremely satisfactory. As with many advances, however, the pendulum may have swung further than is ultimately desirable, with limbs being preserved which are never likely to function effectively.
Such results represent a triumph of enthusiasm for a technique over realism concerning its results. The injury which is likely to be most crippling in the long term is one where there is anaesthesia of the weightbearing surface of the foot. Experience in other contexts has shown that such a foot does not do well. It would be wrong to deprive a patient of the chance to save his lower limb entire but it should also be recognised that on occasion conservation can be carried too far.
With the currently available prostheses, a below-knee amputation need not be a significant disability, and the surgeon needs to compare the alternatives both in terms of final function and in terms of time spent in hospital. Without suggesting that a decision should be made at the acute stage, the possibility that amputation may be required, if the possibility is a real one, should be put to the patient early on, and a decision, if it has to be made, should not be delayed.
As time goes on the patient is likely to become increasingly unrealistic, and unwilling to face an unpleasant truth and, having already spent time, may wish to continue in the forlorn hope of ultimate success.
A further aspect of the management of tibial fractures associated with skin loss which is often neglected concerns the ankle and foot.
In the absence of positive steps taken to prevent its occurrence, one regularly sees clawing of the toes being allowed to develop, often with a degree of foot-drop as well. This becomes increasingly difficult to correct, and left uncorrected, the patient ends up unable to walk properly, even after the fracture is united and the soft tissues are stable.