Radiographic aid of prosthetic fitment in transtibial amputation

Abstract

Prosthetic appropriateness plays an important role in the rehabilitation of a lower-limb amputee. Reduced compliance to wearing prosthesis may be due to consequences of the amputation or an ill-fitting prosthesis. Assessment of prosthetic fitment can be tedious, expensive and inaccessible. Here, we discuss a case of transtibial amputee where prosthetic fitment was assessed by the use of plain radiographs, and modifications were made accordingly. The timeline of events is also described in brief. The patient is a 35-year-old woman, who underwent a below-knee amputation after developing necrotising fasciitis, secondary to a snake bite. After being mobilised with a transtibial prosthesis, the patient was noted to have recurrent ulcers at the distal end of the residual limb. On radiological evaluation and comparison with the radiographs taken in the immediate post-operative period, sequestral bone formation was noted at the distal end of the tibia. Fibular end was noted to be unbevelled and at a longer level than of the tibia. Weight-bearing and non-weight-bearing radiographs with the prosthetic limb showed a reduction of distal end clearance due to pistoning action, indicative of improper prosthetic fitting. Through the use of radiographs, we were able to substantiate objectively, the need for surgical revisions as well as prosthetic modification. Plain radiographs may serve as a cost-effective tool to assess quantitatively and qualitatively the fitting of a prosthesis. In the Indian scenario, it becomes relevant in making surgical and prosthetic decisions, especially in a low-resource setting.