An analysis of iatrogenic complications from the total contact cast.

BACKGROUND

Many physicians continue to fear iatrogenic complications of the total contact cast, and use of this modality has remained restricted to a segment of the orthopaedic and podiatric communities. I examined the actual rate of complications and the factors associated with them in a large consecutive series of total contact casts drawn from the practice of a single surgeon to determine whether this modality is safe for multiple conditions in the neuropathic foot and ankle.

METHOD

A consecutive series of 398 total contact casts spanning a 28-month period from the practice of a single physician were analyzed. All casts were placed by the same team of orthotists. This study comprised 70 patients with severe peripheral neuropathy; an average of 5.69 sequential casts per patient were placed. Three-hundred and sixty-seven casts were placed in diabetic patients, and 31 in patients with idiopathic peripheral neuropathy. By protocol, the initial cast was changed at an interval of no more than 1 week. On occasion, subsequent casts were left on longer, but on average casts were left in place for 7.69 days. Logistic regression analysis was used to analyze the contribution of patient factors to the chance of ulceration.

RESULTS

Complications occurred in 22 casts, including six new pretibial ulcers, six new midfoot ulcers, four forefoot or toe ulcers, five hindfoot ulcers, and one malleolar ulcer. In no case was a preexisting ulcer made worse. This corresponds to an overall complication rate of 5.52% per cast. Overall, 30% of patients suffered one complication during the course of their treatment. With one exception, all new ulcers healed with simple modalities within 3 weeks, often with continued total contact casting. A single cast led to a proximal interphalangeal ulceration that exposed the joint and eventually required toe amputation. The rate of permanent sequelae from cast-related injuries was therefore 0.25%. In no case were the resultant odds ratios statistically different from 1.0, but several trends were observed. Charcot arthropathy represented the highest risk (odds ratio 1.46), while the presence of neuropathic ulceration was surprisingly benign (odds ratio 0.69). The presence of diabetes as opposed to other causes of neuropathy was associated with increased risk (odds ratio 1.34). The use of a cast after deformity-correcting surgery in a neuropathic patient was remarkably safe (odds ratio 0.44), as were casts in which the patient was instructed to remain nonweightbearing (odds ratio 0.27). Patient age was not a factor (odds ratio 1.03). The length of time the cast was left on was not statistically important (odds ratio 0.99), although strict protocols for cast changing likely altered this data.

CONCLUSION

A frequently changed total contact cast is a safe modality for the offloading and immobilization of the neuropathic foot, albeit with an expected constant rate of minor, reversible complications. Patients should be informed of these complications and risks before cast application.