Total Versus Robotic Assisted Unicompartmental Knee Replacement

Total Versus Robotic Assisted Unicompartmental Knee Replacement (TRAKER) for Medial Compartment Osteoarthritis: Randomised Controlled Trial

The purpose of this research is to compare the functional outcomes of patients with end stage medial compartment OA of the knee undergoing a conventional mTKA to those undergoing rUKA and to assess the associated cost economics of such technology.

Unicompartmental knee arthroplasty (UKA) is an accepted surgical alternative to total knee arthroplasty (TKA) for patients with isolated medial compartmental joint disease with the potential advantages of accelerated recovery, improved functional outcomes and retention of anatomical knee kinematics. However, some surgeons continue to favour TKA over UKA due to a lower revision rate. The higher revision rates associated with UKA are thought to be primarily due to component malpositioning and postoperative limb malalignment.

Robotic-arm assisted (r)UKA offers a greater level of precision of component positioning compared to manual UKA and more recently the survivorship of rUKA has been shown to be greater than manual UKA. Early functional outcomes following robotic UKA appear to be better than those observed after manual TKA. Therefore, the benefits of UKA could potentially be enjoyed by the patient without the increased risk of revision when compared to TKA for those with medical compartment disease.

The primary aim of this study is to compare the early knee specific functional outcome of rUKA with manually performed (m)TKA when performed for patients with medial compartment osteoarthritis of the knee.

A single centre randomised control trial will be carried out powered to the Oxford knee score.

Inclusion Criteria:

• Listed for elective primary TKA for end stage medial compartment osteoarthritis
• Intact anterior cruciate ligament
• Full thickness and good quality lateral cartilage
• Correctable intra-articular varus deformity and intact medial collateral ligament
• American Society of Anesthesiologists (ASA) grades 1 and 2
• Male or female, age 50 - 75 at the time of listing for surgery
• Suitable candidate for a cruciate retaining TKA (Triathlon prosthesis) and a UKA

Exclusion Criteria:

• Varus deformity of > 20 degrees
• Fixed flexion of >10 degrees
• Patient is unable to comply with the study protocol (incl. refusal for CT scan) or functional assessments
• Female participants who are pregnant, lactating or planning pregnancy during the course of the study
• Requires patella resurfacing or lateral compartment has significant OA
• Inability to understand the patient information for the study, provide written informed consent or answer study questionnaires for cognitive or language reasons
• Inflammatory disorder e.g. rheumatoid arthritis
• Symptomatic foot, hip or spine pathology
• Prior surgery (other than arthroscopy) or septic arthritis of the knee
• Any other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the study,