Total or Partial Knee Arthroplasty Trial

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.