Prospective Multi-Center Study on Vanguard With E1 Bearing

Inclusion Criteria: Patients will be included in this study if they received Vanguard knee with E1 Bearing per the approved indications for use for Vanguard Knee. Specifically * Painful and disabled knee joint resulting from osteoarthritis or traumatic arthritis where one or more compartments are involved * Correction of varus, valgus, or posttraumatic deformity * Correction or revision of unsuccessful osteotomy Exclusion Criteria: Exclusion Criteria for this study should comply with the stated contraindications on package inserts of Vanguard™ Knee and the E1™ Tibial Bearing. These indications are stated below: Absolute contraindications include: infection, sepsis, osteomyelitis, and failure of a previous joint replacement Relative contraindications include: * Uncooperative patient or patient with neurologic disorders who are incapable of following directions, * Osteoporosis * Metabolic disorders which may impair bone formation * Osteomalacia * Distant foci of infections which may spread to the implant site * Rapid joint destruction, marked bone loss or bone resorption apparent on roentgenogram * Vascular insufficiency, muscular atrophy, neuromuscular disease * Incomplete or deficient soft tissue surrounding the knee