Total knee prosthesis infected with Mycobacterium tuberculosis

Abstract

Mycobacterium tuberculosis (MTB) infection of a prosthetic joint is rarely reported in developed countries.¹ Typically, MTB infection involves the hips or knees, and the infection can occur secondary to crushing and degradation of the granuloma during surgery or, less commonly, from distant foci spreading through the blood. In the present case, MTB infection likely resulted from haematogenous spread since multiple hot spots suggestive of MTB infection were noted in other sites. Early diagnosis allows for antitubercular therapy with retention of the prosthesis, while late diagnosis frequently results in removal and reimplantation of the joint. To avoid major surgery, a high index of suspicion is required to diagnose prosthetic joint tuberculosis.

Figure 1

PA and lateral plain radiograph of the (L) knee joint showing the prosthesis with soft tissue swelling in addition to knee joint effusion. PA, postero-anterior.

Figure 2

(A and B) Increased activity around the left knee prosthesis extending to the lower third of the left femur. (C) A focal increased tracer uptake in fifth and seventh ribs anteriorly.

Figure 3

A white cell count scan revealed abnormal increased white cell count uptake in the region of the left knee before (A) and following treatment (B).