Triathlon® Partial Knee Replacement (PKR) Outcomes Study

Inclusion Criteria:

- The subject is a male or non-pregnant female 21-75 years of age at the time of
enrollment.

- The subject requires a primary cemented unicompartmental knee replacement.

- The subject has a diagnosis of osteoarthritis (OA) or posttraumatic arthritis (TA).

- The subject has clinically intact cruciate and collateral ligaments and no ligamentous
instability is present.

- The subject has less than 10 degrees of flexion contracture and greater than 90
degrees of flexion.

- The subject's preoperative mechanical alignment is less than 10 degrees of varus and
10 degrees of valgus.

- The subject has signed the IRB approved study specific Informed Patient Consent Form.

- The subject is willing and able to comply with postoperative scheduled clinical and
radiographic evaluations and rehabilitation.

Exclusion Criteria:

- The subject has inflammatory arthritis or avascular necrosis(AVN).

- The subject is obese, BMI > 35.

- The subject has a history of total or unicompartmental (contralateral compartment
and/or patellofemoral joint) reconstruction of the affected joint.

- The subject has a history of ACL reconstruction.

- The subject has had a high distal femoral, or proximal tibial osteotomy.

- The subject has a mental, neuromuscular or neurosensory disorder, which would create
an unacceptable risk of prosthesis instability, prosthesis fixation failure, or
complications in post-operative care and/or limit the ability to assess the
performance of the device.

- The subject has a systemic or metabolic disorder leading to progressive bone
deterioration that the surgeon feels would affect the overall outcome of the study.

- The subject is immunologically suppressed, or is receiving chronic steroids (>30 days
duration).

- The subject has a known sensitivity to device materials.

- The subject's bone stock is compromised by disease and/or infection which cannot
provide adequate support and/or fixation to the prosthesis.

- The subject's bone stock is compromised by a prior implantation which cannot provide
adequate support and/or fixation to the prosthesis.

- The subject has an active or suspected latent infection in or about the knee joint.

- The subject is a prisoner.