Medacta GMK Sphere® Multicenter Post-Market Outcomes Study

Inclusion Criteria:

- Patients willing to sign the informed consent

- Patients able to comply with follow-up requirements including postoperative weight
bearing restrictions and self evaluations.

- Male and non-pregnant female patients ages 21 - 80 years of age at the time of
surgery.

- Patients requiring a primary total knee replacement.

- Patients with a diagnosis of osteoarthritis (OA), traumatic arthritis (TA), or
avascular necrosis (AVN).

- Patients with intact collateral ligaments.

Exclusion Criteria:

- Patients with inflammatory arthritis.

- Patients that are morbidly obese, body mass index (BMI) > 40.

- Patients with a history of total or unicompartmental reconstruction of the affected
joint.

- Patients that have had a high tibial osteotomy or femoral osteotomy.

- Patients with neuromuscular or neurosensory deficiency, which would limit the ability
to assess the performance of the device.

- Patients with a systemic or metabolic disorder leading to progressive bone
deterioration.

- Patients that are immunologically compromised, or receiving chronic steroids (> 30
days).

- Patients bone stock is compromised by disease or infection, which cannot provide
adequate support and/or fixation to the prosthesis.

- Patients with knee fusion to the affected joint.

- Patients with an active or suspected latent infection in or about the knee joint.

- Patients that are prisoners.