The images which accompany this article speak for themselves. The patient is in the 6th decade of life and relies on daily doses of Insulin to assist them to manage their diabetic condition. The patient is overweight and not particularly mobile. They had undergone surgery for a bimalleolar fracture of the ankle joint, during which the injury was plated some five weeks prior to these images being recorded.
The patient was sent to the plaster room because of a complaint of pain inside the cast around the heel. This was a significant complaint because the patient had suffered for many years with diabetes induced neurovascular deficits and had severely limited sensory appreciation around the foot and ankle. The cast was a below knee non weight-bearing cast and it had two windows of around 5 square centimetres in size cut from the cast and left overlying each malleolus. This was done ostensibly to ensure that the sutures, which were inserted at the time of surgery, could be removed easily at a later date.
On examination, the cast was constructed from a premium quality white, lightweight, non fibre-glass casting tape (Delta Cast Elite) and it appeared to be padded in the expected manner. Both cast windows were almost completely green in colour suggesting an infection with pseudomonas aeruginosa; if the purulent exudate dripping from both the lateral and medial wounds was anything by which to judge. There was also an overpowering smell that it was impossible to ignore. The patient had been admitted to a hospital medical ward for a pyrexia of unknown origin some three weeks previously. Temperatures of 39.5 degrees celsius were routinely recorded while the patient was in hospital.
The cast was removed and the wounds which appear in these illustrations were discovered. Additionally, there was a necrotic area on the heel that would have been giving the patient discomfort and considerable pain and which had caused them to make a complaint about the pain to the nursing staff; which was never acted upon. The cast windows were not replaced accurately after the sutures were removed. There was no padding with orthopaedic wool or felt under the windows neither were there any wound dressings applied under each of the cast windows.
The image above is the lateral wound. It is very deep and wet with frank pus exudate and erythematous skin surrounding the wound. It is highly unlikely that the metalwork on the lateral side has been spared from this deep wound infection.
The image above depicts the medial wound infection. Ulceration, erythema and necrotic tissue indicate the seriousness of the condition of three week old untreated infected area. Once again it was unlikely that the metalwork on the medial side was spared from becoming infected.
The image above demonstrates an extensive necrotic area, which underlines the continuous pressure which must have been placed on the heel of this patient. This problem has arisen mainly because of a failure of clinical care and lack of attention, which being inadequate had failed to keep the patient safe. A contributing factor may have been due to the patient being almost wholly sensorily deprived in the foot and ankle area because of the neurovascular deficit induced by the diabetic condition. It is no excuse for the failure to care properly for the patient.
No regular wound checks or dressings were carried out after suture removal. No padding to the windows of the cast was supplied. No understanding by the nursing staff was evident when considering the cause of the bilateral cast window discolouration and the strong smells emanating from the cast.
A formal surgical washout and debridement of both wounds was performed. The metalwork had to be removed in this case, thereby undoing the carefully performed surgical procedure. Drug therapy to fight the infection, while hopefully preventing any spread of infection to the bone, was also required. These are the disasterous complicating factors, which may turn out to be progressive and require a below knee amputation.
In general terms, windows cut in casts are not a method of good clinical practice. They are difficult to reapply (especially for non plaster room trained staff) and they are never usually large enough to create an appropriately sized window through which an adequately sized sterile field can be created. They become dirty easily and they encourage wound care that is infrequent because the inspection process may take staff (who are not familiar with a window in a cast) some considerable time.
Windows in casts are usually cut when the limb soft tissues are likely to be vulnerable and increasingly swollen after the insult of surgery. This makes it likely that the soft tissues will protrude through the window if the covers are not replaced firmly. Cast windows are to be deprecated as very poor practice and should be discouraged. If a wound needs inspecting, then it should not be hidden under a completed cast. A well applied posterior slab will support a bony injury repaired with a formal open reduction and an internal fixation procedure.