Ascension® Humeral Resurfacing Arthroplasty Follow-Up Study

Inclusion Criteria: * The following patient will be included in the study - Patient who: * Is treated with the Ascension HRA; * Is disabled by either non-inflammatory or inflammatory arthritis (i.e. rheumatoid arthritis, osteoarthritis and avascular necrosis; * Has mild or moderate humeral head deformity and /or limited motion; * Has post-traumatic arthritis; * Has an intact or reparable rotator cuff; * Has the means and ability to return for all required study visits * Is willing to participate in the study; * Has signed an Informed Consent Form; * Is at least 18 years of age and skeletally mature at the time of surgery; * Is less than 75 years of age at the time of surgery Exclusion Criteria: The following patients will be excluded from the study - Patients who: * Infection, sepsis, and osteomyelitis; * Osteoporosis; * Metabolic disorders which may impair bone formation; * Osteomalacia; * Rapid joint destruction, marked bone loss or bone resorption apparent on X-ray; * Revision procedures where other devices or treatments have failed * Refuses to be in the study; or does not have the means and ability to return for all required study visits; * Currently participating in another clinical study.