Tuberculosis is a generalized disease with a local manifestation. When tuberculosis infection affects the bone and joints, it is termed as Osteoarticular tuberculosis.
Causative agents of osteoarticular tuberculosis are Mycobacterium tuberculosis, Mycobacterium Bovis, Mycobacterium Africanum, and BCG.
Any osteoarticular tubercular lesion is the result of hematogenous dissemination from a primary infected visceral focus.
The primary focus may be active or quiescent, apparent or latent, either in the lungs or in lymph nodes of the mediastinum, mesentery or cervical region or kidney, or other viscera.
The infection reaches the skeletal system through vascular channels, generally the arteries as a result of bacteremia or rarely in axial skeletal through Batson’s venous plexus.
Bone and joint tuberculosis are said to develop generally 2 to 3 years after the primary focus.
Osteoarticular tuberculosis is usually seen in the first three decades of life; however, no age is immune.
Usually, the onset of osteoarticular tuberculosis is insidious with constitutional symptoms like a low-grade fever, lassitude, anorexia, loss of weight, night sweats, tachycardia, and anemia.
Local signs are pain, night cries, painful limitation of movements, muscle wasting, and regional lymph node enlargement.
There are four stages of tuberculosis of the joint.
Stage I is the stage of synovitis where there is a terminal restriction of movements (>75% of movement are present).
Stage II is the stage of early arthritis where 50 to 75% of movements are preserved.
Stage III is the stage of advanced arthritis with loss of movement > 75% in all directions.
Stage IV is the stage of advanced arthritis with subluxation or dislocation of joints.
Blood investigation like complete blood count, erythrocyte sedimentation rate (ESR), CRP is the basic investigations.
Other investigations are the Mantoux test, synovial fluid analysis, and serological investigation.
The basic radiologic investigation includes orthogonal plain radiographic of the affected part and chest radiographs followed by higher investigations like ultrasonography, computed tomography, and magnetic resonance imaging.
Biopsy demonstrating the caseation necrosis with tubercle is the diagnostic of tuberculosis.
General measures include rest, immobilization with braces, or traction to correct the deformity and to maintain limb in a functional position.
The specific measure includes anti-tubercular drug therapy with surgical intervention if necessary.
Osteoarticular tuberculosis treated in early stages results in a good response with complete resolution of the lesion.
Inadequately or inappropriately treated cases result in gross deformities with ankylosis and limb length discrepancy.