Arthroplasty, also known as joint replacement, is the operative procedure for construction of a new movable joint. It is a surgical procedure to restore the integrity and function of the joint. Common arthroplasties are of following types :1) Hip arthroplastyFollowing type of hip arthroplasties are there :Total hip replacement : Both parts of joint, i.e. femoral head and acetabulum, are replaced by prosthesis. Hemi-arthroplasty (hemi-replacement) : Only one part of the joint, i.e. femoral head, is replaced without putting acetabular component. Examples are Bipolar hemiarthroplasty and unipolar herniartroplasty (AMR). Surface replacement (resurfacing procedure) : Only diseased surface of femoral head is resected and is replaced by metal surface.'Important indications for TKRArthritis : Rheumatoid arthritis, ankylosing spondylitis, osteoarthritis (primary or secondary) Avascular necrosis of femoral head due to alcoholism, non-union femoral neck fracture and cortisone Bone tumor involving proximal femur or acetabulum. Failed hemiarthroplasty Old healed infection (TB or pyogenic)2) Knee arthroplastyKnee arthroplasties may be of following types :Total knee replacement : Complete joint, i.e. both condyles of femur, both tipial plateau and patella are resected and replaced by prosthesis. Unicondylar replacement : Only one condyle (medial or lateral) of femur is replaced. Patellar resurfacing : Diseased part of patella is resected and resurfaced.Important indications of TKRArthritis : RA, OA, Postraumatic arthritis, inflammatory arthritis (gout Hemophilia Tumors3)    Elbow arthroplastyThe elbow joint (heumero-ulnar joint) is replaced by an artificial hinged elbow prosthesis.Important indications for elbow replacementPain & instability Ankylosis in non-functional position (e.g. in RA)