Diagnosis and treatment of tuberculosis of the foot and ankle-A literature review

Abstract

Foot osteoarticular tuberculosis is uncommon. Late diagnosis and sub-optimal management can lead to significant morbidity, deformity and even death. Preservation of life, limb and function can be achieved with prompt diagnosis and treatment. In 1882, Robert Koch published his discovery of mycobacterium tuberculosis as the causative agent of tuberculosis (TB), and showed the disease was infectious rather than inherited. Over two centuries later, TB remains one of the top 10 causes of death worldwide. Whilst in 90% of cases TB infects the respiratory system, in 10% it is extrapulmonary and can infect the skeletal, nervous, lymphatic and genitourinary systems. The spine is the most frequently affected site in the musculoskeletal system and this is known as Pott's disease. The foot and ankle is affected in only 0.13% cases of extrapulmonary TB. A high index of suspicion is thus required. This infrequency in incidence, heterogeneity of its presentation along with the difficulty in early diagnosis often causes significant delays in its treatment and hence results in a considerable disability. The medical treatment is well established but the role of surgery, its usefulness and its correct timing remain controversial. The main diagnostic issues include imaging being non-specific. Plain radiographs remain the first line imaging modality. MRI and CT scans provide greater detail and capture the disease at an earlier stage. Microbiological testing has low sensitivity and specificity becasue TB lesions are paucibacillary. Bone biopsy is of significant diagnostic value as it not only allows histological examination to detect granulomas but enables sensitivity and resistance testing of anti-tuberculous therapy (ATT). Issues relating to treatment include timing, duration, combination of chemotherapy and the challenge of multi drug resistant tuberculosis MDR-TB. The selection and timing of appropriate surgical techniques and optimal duration of follow-up are further points to consider. In this article we aim to review the literature on diagnosis and treatment of foot and ankle TB.

Keywords: Diagnosis; Foot and ankle; Osteoarticular; Surgery; Treatment; Tuberculosis.