Pannus is seen in

Rheumatoid ahritis Distribution: Symmetric small joints- MCP, PIP joints and spares DIP joint Autoantibodies in RA Rheumatoid factor - An autoantibody directed against Fc region of IgG which is positive in about 50% of cases at presentation. Anti-cyclic citrullinated peptide (anti-CCP) antibodies - 90-98% specific for RA which correlate strongly with erosive disease.ACR Diagnostic criteria for RA: Morning stiffness in and around joint lasting for atleast 1 hour Ahritis in at least three or more jointsAhritis in hand jointsSymmetric ahritisRheumatoid nodules - Pathgnomonic Serum rheumatoid factorRadiographic changes like bony erosion, periaicular osteoporosis & narrowing of joint space Diagnostic criteria - At least 4 or more criteria must be present to diagnose RA Rheumatoid deformitiesSwan-neck deformity: flexion posture of the DIP and hyperextension posture of the PIP joints.Buttonhole or Boutonniere Deformity: PIP in flexion, DIP in hyperextension.Wind sweep deformity: hallux valgus on one side & hallux varus on other side- produce deformity which are parallel to each other. Intrinsic plus deformity: caused by tightness and contracture of the intrinsic muscles, seen in RA, Cerebral palsy etc. Here the IP joints are in extension & MCP joints are in flexion. Z deformity: Radial detion of wrist joint with ulnar detion of MCP joints.Pannus may form in RA, with underlying cailage destruction. With time, synol fibrosis occurs, resulting in joint stiffness(Refer: Mohindra's Fundamentals of Ohopedics, 2nd edition, pg no. 418, 419)