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Total or Partial Knee Arthroplasty Trial (TOPKAT)

This study is ongoing, but not recruiting participants.
University of Aberdeen
Information provided by (Responsible Party):
University of Oxford Identifier:
First received: April 20, 2011
Last updated: October 25, 2013
Last verified: October 2013

In the majority of patients with osteoarthritis of the knee the disease originates in the medial compartment. There are two different approaches to replacing this arthritic area. Some surgeons feel that it is always best to replace both the knee compartments with a Total Knee Replacement (TKR). Others feel it is best to replace just the damaged component of the knee with a Unicompartmental Knee Replacement (UKR). There is little agreement amongst knee surgeons. Both interventions are established and well documented procedures, yet little evidence exists to support either practice. Each intervention is considered standard care. There exists little evidence, however, to prove the clinical and cost effectiveness of either management option.

The aim of the Total or Partial Knee Arthroplasty Trial (TOPKAT) will be to assess the clinical and cost effectiveness of Total Knee Replacements versus Unicompartmental Knee Replacements in patients with medial osteoarthritis. This will be examined using an appropriate patient base and long term assessments.

The trial has a combined device/expertise based allocation depending on the local situation. Surgeons who are in equipoise and have sufficient experience to perform both TKR and UKR, randomisation and allocation can be based on "device" (UKR or TKR). The same surgeon will perform the operation for both arms of the study.

For surgeons who hold a preference for one treatment over the other, an "expertise" based randomisation will then occur. UKR surgeons will work alongside TKR surgeons. Patients recruited to the study from these sites will be randomised to one of the treatment options and treated by the appropriate surgeon. In such cases the patient is internally referred to the other surgeon's operating list.

Patients will be recruited by their consultant knee surgeons in collaboration with the local research team. TOPKAT are hoping to recruit 500 patients altogether, with 250 per arm of the trial.

Condition Intervention
Knee Osteoarthritis
Procedure: Unicompartmental Knee Replacement
Procedure: Total Knee Replacement

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment

Resource links provided by NLM:

Further study details as provided by University of Oxford:

Primary Outcome Measures:
  • Pain and Function [ Time Frame: Year 5. ] [ Designated as safety issue: No ]
    This will be measured by using the Oxford Knee Score, a pateint reported outcome questionnaire.

Secondary Outcome Measures:
  • Range of Motion and Function [ Time Frame: Year 5. ] [ Designated as safety issue: No ]
    This will be measured using the American Knee Society Score (AKSS). A clinician assessed score examining pain, stability, range of movement and function.

  • Activity level [ Time Frame: Year 5. ] [ Designated as safety issue: No ]
    This will be measured using two patient reported questionnaires, the University of California, Los Angeles (UCLA) Activity Score and the High Activity Arthroplasty Score.

  • Economic Evaluation [ Time Frame: Year 5. ] [ Designated as safety issue: No ]
    The EuroQol (EQ-5D) a patient reported questionnaire will provide data for economic evaluation.

  • Patient Satisfaction [ Time Frame: Year 5. ] [ Designated as safety issue: No ]
    Patient satisfaction will be measured using the Lund Score.

Estimated Enrollment: 500
Study Start Date: January 2010
Estimated Study Completion Date: December 2018
Estimated Primary Completion Date: September 2018 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Unicompartmental Knee Replacement Procedure: Unicompartmental Knee Replacement
Total Knee Replacement Procedure: Total Knee Replacement


Ages Eligible for Study:   40 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria

  • Medial compartment osteoarthritis with exposed bone on both femur and tibia
  • Functionally intact Anterior Cruciate Ligament (superficial damage or splitting is acceptable)
  • Full thickness and good quality lateral cartilage present
  • Correctable intra-articular varus deformity (suggestive of functionally intact medical cruciate ligament)
  • Medically fit showing an American Society of Anesthesiologists (ASA) of 1 or 2

Exclusion Criteria

  • Require revision knee replacement surgery
  • Have rheumatoid arthritis or other inflammatory disorders
  • Are unlikely to be able to perform required clinical assessment tasks
  • Have symptomatic foot, hip or spinal pathology
  • Previous knee surgery other than diagnostic arthroscopy and medial menisectomy
  • Previously had septic arthritis
  • Have significant damage to the patella-Femoral Joint especially on the lateral facet.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01352247

United Kingdom
Nuffield Orthopaedic Centre NHS Trust
Oxford, Oxfordshire, United Kingdom, OX3 7LD
Sponsors and Collaborators
University of Oxford
University of Aberdeen
Principal Investigator: David Beard, DPhil University of Oxford
  More Information

Additional Information:
No publications provided by University of Oxford

Additional publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: University of Oxford Identifier: NCT01352247     History of Changes
Other Study ID Numbers: 09/H0606/88, ISRCTN03013488
Study First Received: April 20, 2011
Last Updated: October 25, 2013
Health Authority: United Kingdom: National Institute for Health Research
United Kingdom: Research Ethics Committee

Additional relevant MeSH terms:
Osteoarthritis, Knee
Joint Diseases
Musculoskeletal Diseases
Rheumatic Diseases processed this record on November 20, 2014