For Healthcare Professionals

Triathlon® Partial Knee Replacement (PKR) Outcomes Study


About the study

The purpose of this study is to compare the 10-year Knee Society Score (KSS) functional results of the Triathlon PKR Unicondylar Knee to the 10-year Knee Society Score (KSS) functional results of the Triathlon Cruciate Retaining (CR) Total Knee.

Who can take part

You may be eligible to participate in the study if you meet the following criteria:


  1. The subject is a male or non-pregnant female 21-75 years of age at the time of enrollment.
  2. The subject requires a primary cemented unicompartmental knee replacement.
  3. The subject has a diagnosis of osteoarthritis (OA) or posttraumatic arthritis (TA).
  4. The subject has clinically intact cruciate and collateral ligaments and no ligamentous instability is present.
  5. The subject has less than 10 degrees of flexion contracture and greater than 90 degrees of flexion.
  6. The subject's preoperative mechanical alignment is less than 15 degrees of varus and 15 degrees of valgus.
  7. The subject has signed the Institutional Review Board (IRB) approved study specific Informed Patient Consent Form.
  8. The subject is willing and able to comply with postoperative scheduled clinical and radiographic evaluations and rehabilitation.


  1. The subject has inflammatory arthritis or avascular necrosis(AVN).
  2. The subject is obese, BMI > 35.
  3. The subject has a history of total or unicompartmental (contralateral compartment and/or patellofemoral joint) reconstruction of the affected joint.
  4. The subject has a history of anterior cruciate ligament (ACL) reconstruction.
  5. The subject has had a high distal femoral, or proximal tibial osteotomy.
  6. 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.
  7. 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.
  8. The subject is immunologically suppressed, or is receiving chronic steroids (>30 days duration).
  9. The subject has a known sensitivity to device materials.
  10. The subject's bone stock is compromised by disease and/or infection which cannot provide adequate support and/or fixation to the prosthesis.
  11. The subject's bone stock is compromised by a prior implantation which cannot provide adequate support and/or fixation to the prosthesis.
  12. The subject has an active or suspected latent infection in or about the knee joint.
  13. The subject is a prisoner.
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Study Locations

Enter your ZIP code/Postal code/PIN code to locate study sites near you:

How to Apply

Contact the study center to learn if this study is a good match for you.
Phone iconCall 201-831-5893Email iconEmail Study Center

Study’s details


Arthroplasty, Replacement, Knee





Participants needed


Est. Completion Date

Jan 2029

Treatment type



Stryker Orthopaedics identifier


Study number


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