Scientific evidence for the use of modern unicompartmental knee arthroplasty

Abstract

Unicompartmental knee arthroplasty as a surgical treatment for monocompartmental knee arthritis remains a controversial procedure with questions surrounding the benefits and survivorship of the procedure versus osteotomies or total knee arthroplasties. The authors, by examining the complete body of literature for scientific evidence concerning the procedure, will describe the history of usage of these prostheses, their rationale for usage, modern devices and their results, and why they may have advantages as a treatment modality for monocompartmental knee arthritis. Outcomes of current unicompartmental designs will be presented and evaluated to determine which aspects of the design and patient selection technique are associated with success or failure. Commonly asked questions regarding the use of these devices will be addressed. The authors will also describe some potential modifications that might affect the use of these components in the future, including minimally invasive procedures and robotics, and how these devices may change over the next 5 years.

Unicompartmental and Total Knee Arthroplasty in the Same Patient

“…Preservation of the anterior cruciate ligament may also be beneficial and some studies have reported improved function in stair climbing and proprioception after unicompartmental knee arthroplasty. 22,23 Appropriate patient selection and component selection is important to increase survivorship in unicompartmental knee arthroplasty. These advantages may still have been obtained in the survivors who had a unicompartmental knee arthroplasty.…”

Obesity has no effect on outcomes following unicompartmental knee arthroplasty

“…Unicompartmental knee arthroplasty (UKA) has gained renewed interest in the past decade as an alternative to total knee arthroplasty (TKA) for selected patients with degenerative joint disease limited to the lateral or medial compartment of the knee [4, 33, 36]. The advantages of UKA over TKA are reduced blood loss, less perioperative morbidity, faster recovery and rehabilitation, as well as increased postoperative range of motion compared to total knee arthroplasty [6, 10, 17, 26, 34, 42].…”

“…Robotic‐assisted systems are available for UKA and have been shown to improve component positioning compared to conventional manual UKA procedures [15, 17, 31, 35, 43, 48]. UKA is technically challenging, and precise component placement is vital for implant survival [3, 17, 32, 36, 37, 47, 55], where over‐ or under‐correction by as little as 2° may lead to improper component placement, possibly increasing polyethylene wear of the tibial component, leading to progression of osteoarthritic changes in other compartments of the knee, or causing anterior knee pain [3, 16, 17, 25, 34, 37, 41, 42, 46]. In cadaveric and clinical studies, robotic‐assisted UKA was found to have less variability in implant position compared to manual component insertion by the same surgeon [14, 35].…”

Fixed- versus mobile-bearing unicondylar knee arthroplasty: are failure modes different?

“…The debate of whether MB UKA offers clinical and radiographic advantages over FB UKA for isolated end‐stage symptomatic osteoarthritis of the knee has continued to generate substantial controversy in the orthopedic community [5, 42, 63]. Although there is already a meta‐analysis on clinical differences between fixed‐ and mobile‐bearing UKAs [63], more RCTs have been coming out with different outcomes in the past few years [3, 7, 51, 67].…”