5-Year Survivorship and Outcomes of Robotic-Arm-Assisted Medial Unicompartmental Knee Arthroplasty

摘要

Purpose. While unicompartmental knee arthroplasty (UKA) has demonstrated benefits over total knee arthroplasty (TKA) in selected populations, component placement continues to be challenging with conventional surgical instruments, resulting in higher early failure rates. Robotic-arm-assisted UKA (RA-UKA) has shown to be successful in component positioning through preop planning and intraop adjustability. The purpose of this study is to assess the 5-year clinical outcomes of medial RA-UKA. Methods. This study was a retrospective review of a single-center prospectively maintained cohort of 133 patients (146 knees) indicated for medial UKA from 2009 to 2013. Perioperative data and 2- and 5-year Knee injury Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Score (WOMAC), and Forgotten Joint Score (FJS) outcome measures were collected. Five-year follow-up was recorded in 119 patients (131 knees). Results. Mean follow-up was <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mn>5.1</a:mn> <a:mo>±</a:mo> <a:mn>0.2</a:mn> </a:math> years. Mean age and BMI were <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mn>68.0</c:mn> <c:mo>±</c:mo> <c:mn>8.1</c:mn> </c:math> years and <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" id="M3"> <e:mn>29.3</e:mn> <e:mo>±</e:mo> <e:mn>4.7</e:mn> </e:math> kg/m2, respectively. At 2-year follow-up, mean KOOS, WOMAC, and FJS were <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" id="M4"> <g:mn>71.5</g:mn> <g:mo>±</g:mo> <g:mn>15.3</g:mn> </g:math> , <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" id="M5"> <i:mn>14.3</i:mn> <i:mo>±</i:mo> <i:mn>7.9</i:mn> </i:math> , and <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" id="M6"> <k:mn>79.1</k:mn> <k:mo>±</k:mo> <k:mn>25.8</k:mn> </k:math> , respectively. At 5-year follow-up, mean KOOS, WOMAC, and FJS were <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" id="M7"> <m:mn>71.6</m:mn> <m:mo>±</m:mo> <m:mn>15.2</m:mn> </m:math> , <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" id="M8"> <o:mn>14.2</o:mn> <o:mo>±</o:mo> <o:mn>7.9</o:mn> </o:math> , and <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" id="M9"> <q:mn>80.9</q:mn> <q:mo>±</q:mo> <q:mn>25.1</q:mn> </q:math> , respectively. Mean change in KOOS and WOMAC was <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" id="M10"> <s:mn>34.6</s:mn> <s:mo>±</s:mo> <s:mn>21.4</s:mn> </s:math> and <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" id="M11"> <u:mn>11.0</u:mn> <u:mo>±</u:mo> <u:mn>13.6</u:mn> </u:math> , respectively ( <w:math xmlns:w="http://www.w3.org/1998/Math/MathML" id="M12"> <w:mi>p</w:mi> <w:mo>&lt;</w:mo> <w:mn>0.001</w:mn> </w:math> and <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" id="M13"> <y:mi>p</y:mi> <y:mo>&lt;</y:mo> <y:mn>0.001</y:mn> </y:math> ). For patient satisfaction at last follow-up, 89% of patients were very satisfied/satisfied and 5% were dissatisfied. For patient activity expectations at last follow-up, 85% met activity expectations, 52% were more active than before, 25% have the same level of activity, 23% were less active than before, and 89% were walking without support. All patients returned to driving after surgery at a mean <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" id="M14"> <ab:mn>15.2</ab:mn> <ab:mo>±</ab:mo> <ab:mn>9.4</ab:mn> </ab:math> days. Survivorship was 95% (95% CI 0.91-0.98) at 5 years. One knee (1%) had a patellofemoral revision, two knees (1.3%) were revised to different partial knee replacements, and five knees (3.4%) were converted to TKA. Conclusion. Overall, medial RA-UKA demonstrated improved patient-recorded outcomes, high patient satisfaction, met expectations, and excellent functional recovery. Midterm survivorship was excellent. Longitudinal follow-up is needed to evaluate long-term outcomes of robotic-arm-assisted UKA procedures.