Abstract
INTRODUCTION
Successful clinical outcomes following unicompartmental knee arthroplasty (UKA) depend on component positioning, soft tissue balance and overall limb alignment which can be difficult to achieve using manual instrumentation. Recently, robotically guided technology has been used to improve post-operative implant positioning, and limb alignment in UKA with the expectation that this will result in greater implant longevity. This multi-center study examines the survivorship of this robotically guided procedure coupled with a novel, anatomically designed UKA implant at two years follow up.
OBJECTIVES
This study examines the two year survivorship and patient satisfaction of an anatomically designed UKA implant using a new robotically guided technology that has been shown to improve implant positioning and alignment.
METHODS
788 patients (890 knees) from 6 surgeons underwent robotically guided unicompartmental arthroplasty surgery and reached a minimum two year follow-up. The tibial component was a fixed bearing, metal backed onlay design. Patients were consecutive for each respective surgeon and were also each surgeon's first series of patients for that implant system. As part of an IRB approved study, every patient was contacted and asked a series of five questions to determine implant survivorship and patient satisfaction at a two year follow up. 620 patients (701 knees) enrolled in the study; the overall enrollment rate was 79%. There were 352 males and 266 females; the average age was 70 ± 9.23 years (range: 39–93) and the average BMI was 29.35 ± 4.59 (range: 18.97–47.77). The average follow up at the time the patients were contacted was 30 ± 5.53 months (range: 22–42).
RESULTS
Eight knees were reported as revised within 24 months after the index procedure, yielding a two year revision rate of 1.1%. The average time to revision was 11 months. Five patients returned to their same surgeon for the revision procedure. Seven knees were revised to a total knee arthroplasty; one knee was revised to another unicompartmental knee arthroplasty. 71% of patients reported feeling “Very Satisfied” with their overall knee function. 22% of patients reported feeling “Satisfied,” 3% of patients reported feeling “Neutral,” 3% of patients reported feeling “Dissatisfied,” and 1% of patients reported feeling “Very Dissatisfied”.
CONCLUSIONS
Excellent survival and satisfaction outcomes were noted in this subset of patients at two years post-operative. This robotically guided procedure shows promise of improved survivorship rates for UKA compared to what is currently reported in implant registries and comparative studies. These promising results indicate that improved implant placement accuracy achieved with robotic assistance leads to improved implant survivorship and patient outcomes.
