Henderson Nancy, Riddle Daniel L
Assistant Professor, Department of Rehabilitation Sciences, Georgia Southern University- Armstrong campus, Savannah, GA, USA.
Departments of Physical Therapy, Orthopaedic Surgery and Rheumatology, Virginia Commonwealth University, 900 East Leigh Street, Room 4:100, Richmond, VA, USA.
J Clin Epidemiol. 2022 Dec;152:201-208. doi: 10.1016/j.jclinepi.2022.10.019. Epub 2022 Oct 28.
Traditionally, the minimal clinically important difference (MCID) is used to judge the meaningfulness of outcomes in total knee arthroplasty (TKA). However, MCID estimates do not consider patient costs, potential side effects, and inconveniences. MCIDs vary substantially across TKA studies and have several conceptual and psychometric problems. A more scientifically sound alternative for estimating benefits patients expect TKA is the smallest worthwhile effect (SWE), measured with the benefit-harm trade-off method.
We recruited 121 participants and followed them for 6 months after surgery. All participants completed Knee Injury and Osteoarthritis Score (KOOS) Pain and Function, and underwent an interview using the benefit-harm trade-off method.
The absolute SWE at the 50th percentile (approximating the average patient) was 31 points KOOS Pain improvement and 28 points for KOOS Function, daily living. Construct validity was supported with strong associations between meeting SWE (yes or no) and satisfaction with 6-month outcome (yes or no) using Pearson Chi Square (24.5, P < 0.001).
Current MCID-based methods for interpreting KOOS change scores have flaws while the SWE method is conceptually superior. We determined the SWE of TKA that would justify the costs, risks, and inconveniences of surgery. SWE estimates suggest that patients expect a substantially greater change in KOOS scores than would be expected using MCID estimates. Clinicians can use SWE estimates when discussing likely outcomes and potential TKA benefits and risks with their patients.
传统上，最小临床重要差异（MCID）用于判断全膝关节置换术（TKA）结果的意义。然而，MCID评估未考虑患者成本、潜在副作用和不便之处。TKA研究中的MCID差异很大，并且存在一些概念和心理测量问题。一种在科学上更合理的评估患者对TKA预期益处的替代方法是最小值得效果（SWE），采用利弊权衡法进行测量。
我们招募了121名参与者，并在术后对他们进行了6个月的随访。所有参与者完成了膝关节损伤和骨关节炎评分（KOOS）疼痛与功能评估，并采用利弊权衡法进行了访谈。
第50百分位数（接近平均患者）的绝对SWE为KOOS疼痛改善31分，KOOS功能（日常生活）改善28分。使用Pearson卡方检验（24.5，P < 0.001），达到SWE（是或否）与对6个月结果的满意度（是或否）之间存在强关联，支持了结构效度。
当前基于MCID解释KOOS变化分数的方法存在缺陷，而SWE方法在概念上更具优势。我们确定了TKA的SWE，该SWE能够证明手术的成本、风险和不便之处是合理的。SWE估计表明，患者期望KOOS分数的变化幅度比使用MCID估计所预期的值要大得多。临床医生在与患者讨论可能的结果以及TKA的潜在益处和风险时可以使用SWE估计。
