Acceptable outcome following resection of bilateral large popliteal space heterotopic ossification masses in a spinal cord injured patient: a case report

Abstract

Spinal cord injury is a well-known predisposing factor for development of heterotopic ossification around the joints especially hip and elbow. Heterotopic ossification about the knee is usually located medially, laterally or anteriorly; besides, the knee is generally fixed in flexion. There are only a few reports of heterotopic bone formation at the posterior aspect of the knee (popliteal space) and fixation of both knees in extension; so, there is little experience in operative management of such a problem.Here, we present a 39-years old paraplegic man who was referred to us five years after trauma with a request of above knee amputation due to sever impairment of his life style and adaptive capacity for daily living because of difficulties in using wheelchair. The principle reason for the impairment was fixed full extension of both knees as the result of bilateral large heterotopic ossification masses in popliteal fossae. The bony masses were surgically resected with acceptable outcome. The anatomic position of the ossified masses as well as ankylosis of both knees in full extension, and the acceptable functional outcome of surgery which was done after a long period of five years following injury makes this case unique.

Figure 1

Physical examination of the patient, the knee is stiff in extension and ankle is fixed in equinus position.

Figure 2

Lateral radiography of the right knee, large mass of heterotopic bone is seen bridging the knee joint posteriorly.

Figure 3

CT Angiography of the knees; both popliteal arteries encased in grooves of the heterotopic bone.

Figure 4

Gastrocnemius and the hamstrings were not involved in the heterotopic bone mass.