• Patient is 18 years of age or older.

• Patient must have signed Institutional Review Board (IRB)/Ethics Committee (EC)-approved informed consent.

• Patient is a candidate for primary or revision total elbow arthroplasty, based on symptoms including at least one of the following:

‣ Elbow joint destruction which significantly compromises daily living activities

⁃ Post-traumatic lesions or bone loss contributing to elbow instability

⁃ Ankylosed joints, especially cases of bilateral ankylosis from causes other than active sepsis

⁃ Advanced rheumatoid arthritis, post-traumatic, or degenerative arthritis with incapacitating pain

⁃ Instability or loss of motion when the degree of joint or soft tissue damage precludes reliable osteosynthesis

⁃ Acute comminuted articular fracture of elbow joint surfaces that precludes less radical procedures, including 13-C3 fractures of the distal humerus

• Patient is willing and able to complete scheduled follow-up evaluations as defined by the protocol.

∙ Additional Retrospective Arm Inclusion Criteria

• Patient must have undergone a total elbow replacement with the Nexel system between July 2013 and the date of the site initiation visit.

• Patient information available for each retrospective patient must, at minimum, include preoperative demographic information, preoperative physical exam information, the index surgery operative report, and details of the devices implanted.