Deformity is most commonly seen in primary osteoarthritis of the knee joint -: (A) Genu valgum, (B) Germ recurratum, (C) Genu varus, (D) Procurvaturn.
Answer is C. In knee joint osteoarthritis, medial joint space is affected earliest and causes asymmetrical joint space narrowing. This results in varus deformity (genu varus).