MDR ExploR Radial Head System PMCF

Inclusion Criteria: Patient must have undergone primary elbow arthroplasty with the ExploR Radial Head System according to a cleared indication, which includes the following: * Replacement of the radial head for degenerative or post-traumatic disabilities presenting pain, crepitation and decreased motion at the radio-humeral and/or proximal radio-ulnar joint with: Joint destruction and/or subluxation visible on x-ray Resistance to conservative treatment * Primary replacement after fracture of the radial head * Symptomatic sequelae after radial head resection Patient must be 18 years of age or older. Patient must be willing and able to follow directions. Exclusion Criteria: * Infection * Sepsis * Osteomyelitis * Uncooperative patient or patient with neurological disorders who are incapable of following directions * Osteoporosis * Metabolic disorders which may impair bone formation * Osteomalacia * Distant foci of infections which may spread to implant site * Rapid joint destruction, marked bone loss or bone resorption apparent on roentgenogram * Patient is a prisoner. * Patient is a current alcohol or drug abuser. * Patient has a psychiatric illness or cognitive deficit that will not allow for proper informed consent * Patient is known to be pregnant or breastfeeding. * Patient is unwilling to sign informed consent.