Persona Partial Knee Study

This study will compare functional and clinical outcomes of partial knee joint replacement using the Persona Partial Knee (PPK) and a standard care total knee replacement. Reported benefits of unicompartmental knee arthroplasty (UKA) compared to total knee arthroplasty (TKA) are less invasive surgery, less post-operative pain, quicker recovery, shorter inpatient stay, preservation of the anterior cruciate ligament (ACL), better knee function and lower risk of complications. Also, the PPK more closely matches the anatomy of knee and has more sizing options. These aim to allow the surgeon to reconstruct the knee to better match the native knee and achieve natural function. Little data exists which investigates biomechanical function of patients after UKA or comparisons between UKA and TKA and none investigating the PPK. Available data focuses on level walking which is not particularly challenging for these patients and is unlikely to highlight biomechanical differences between UKA and TKA. The investigators will investigate biomechanical differences between UKA and TKA during more challenging activities. These will mirror activities of everyday life: sitting into/rising from a chair, stepping, walking on a slope. The investigators will investigate level walking as all studies of this nature report these data. Unlike TKA, UKA retains the ACL. The soft tissues of the knee play a role in balance control and the investigators will assess this with single leg balancing. Biomechanical differences will be assessed using 3D motion analysis before and after surgery (6 and 12 months). Comparisons will be made within and between groups and between the patient groups and existing healthy data. Radiographic and patient reported outcomes (satisfaction, pain and functional abilities) will be investigated. Fifty patients will be recruited and randomised to undergo TKA or UKA. Only patients who are suitable for UKA will be recruited. Data for 25 healthy, matched controls from the i