Academic Unit of Trauma and Orthopaedics, University of Genoa, Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132, Genoa, Italy.
Academic Department of Trauma and Orthopaedics, School of Medicine, University of Leeds, Leeds General Infirmary, Clarendon wing, Level D, LS13EX, Leeds, West Yorkshire, UK.
Int Orthop. 2020 Jan;44(1):161-172. doi: 10.1007/s00264-019-04376-0. Epub 2019 Aug 22.
The aim of this case-control study was to develop a clinical decision rule to support assessment of the risk of long-bone non-union and plan for appropriate early intervention.
Two hundred patients (100 cases and 100 controls) were recruited. Risk factors identified to contribute to the development of non-union were recorded and analysed with a multivariable logistic regression model. Tabulation of the outcome (non-union/union) against each risk factor in turn (univariable analysis) was carried out. Odds ratios and confidence intervals were derived using Wald's method. A receiver-operator curve was calculated and the area under the curve was computed. Having established the eight most important risk factors, a non-union risk index was developed as the count of the risk factors present in each patient.
The five risk factors for non-union with greater effect size were post-surgical fracture gap > 4 mm (odds ratio (OR) = 11.97 95% CI (4.27, 33.53)), infection superficial/deep (OR 10.16 (2.44, 42.36)), not optimum mechanical stability (OR 10.06 (3.75, 26.97)), displacement > 75% of shaft width (OR 6.81 (2.21, 20.95)), and site of fracture-tibia (OR 4.33 (1.32, 14.14)). The ROC curve for the non-union index was 0.924, sensitivity 91%, specificity 77%.
The non-union index derived from counting risk factors predicts union for 0-4 risk factors and non-union for 5-8 risk factors. It can be readily applied and can guide clinicians about the risk of development of long-bone non-union. It can become a powerful aid for assessing fracture fixation outcome and to support early intervention.
本病例对照研究旨在制定临床决策规则，以支持评估长骨骨折不愈合的风险，并计划进行适当的早期干预。
共招募了 200 名患者（100 例病例和 100 例对照）。记录并分析了确定与骨折不愈合发生相关的危险因素，采用多变量逻辑回归模型。依次对每个危险因素（单变量分析）的结果（骨折不愈合/愈合）进行制表。使用 Wald 方法得出比值比和置信区间。绘制受试者工作特征曲线并计算曲线下面积。在确定了 8 个最重要的危险因素后，开发了骨折不愈合风险指数，即每位患者存在的危险因素数量。
五个具有较大影响大小的骨折不愈合危险因素为术后骨折间隙>4mm（比值比（OR）=11.97，95%可信区间（CI）（4.27，33.53））、浅表/深部感染（OR 10.16（2.44，42.36））、机械稳定性不理想（OR 10.06（3.75，26.97））、>75%骨干宽度的位移（OR 6.81（2.21，20.95））和骨折部位-胫骨（OR 4.33（1.32，14.14））。骨折不愈合指数的 ROC 曲线为 0.924，敏感性 91%，特异性 77%。
从计数危险因素得出的骨折不愈合指数可预测 0-4 个危险因素的愈合和 5-8 个危险因素的不愈合。它易于应用，可以指导临床医生评估长骨骨折不愈合的风险。它可以成为评估骨折固定效果和支持早期干预的有力辅助工具。
