A 30-year-old HIV positive male who is on antiretroviral therapy has pain in the right hip joint for 2 months. He has difficulty in abduction and internal rotation. Which of the following is most likely diagnosis?
Avascular necrosis has been assosciated with antiretroviral therapy, also FABER (Flexion, Abduction, External Rotation) deformity is seen in AVN. On the other hand in AIDS progression of disease is very rapid from tubercular synovitis to arthritis hence there is deformity of FADIR (Flexion, Adduction and Internal Rotation) in tubercular arthritis and not FABER which is seen in tubercular synovitis. Hence AVN is a better answer here.
a. TB arthritis of the hip: The disease is of insidious in onset and runs a chronic course. Pain may be absent in the early stages, or if present, it may be referred to the knee. The patient complaints of ‘night cries’, caused by the rubbing of the two diseased surfaces when the movement occurs as a result of the muscle relaxation during sleep.
b. Gross deformities may be obvious on inspection. Minimal deformities are compensated for by pelvic tilt and can be made obvious by tests. Commonly it is flexion, adduction and internal rotation deformity of the hip. There is generally a true shortening of limb in T.B. of the hip, except in Stage I, in which an apparent lengthening occurs.
c. Stages of TB of the hip:
i. Stage I (stage of synovitis): There is effusion into the joint which demands the hip to be in a position of maximum capacity. This is a position of flexion, abduction and external rotation. This stage is also called the stage of apparent lengthening. It lasts for a very short period.
ii. Stage II (stage of the arthritis): Hip takes the attitude of flexion, adduction and internal rotation. This is also called the stage of apparent shortening.
iii. Stage III (stage of erosion): The attitude of the limb is the same as that in Stage II, i.e., flexion, adduction and internal rotation except for the fact that the deformities are exaggerated. There is true shortening of the limb because of the actual destruction of the bone.