Construction and internal validation of a nomogram model for predicting early tibial component loosening after unicompartmental knee arthroplasty in elderly patients with osteoporosis

LI Jiangbo; ZHANG Eryang; WANG Kunzheng

doi:10.3969/j.issn.1674-3806.2026.02.05

Abstract：Objective To construct and internally validate a nomogram model for predicting early tibial component loosening after unicompartmental knee arthroplasty(UKA)in elderly patients with osteoporosis.Methods The clinical data of 125 elderly patients with osteoporosis who underwent UKA in Yuncheng Central Hospital Affiliated to Shanxi Medical University due to knee osteoarthritis from May 2022 to May 2023 were retrospectively collected.Among the patients,21 patients had early tibial component loosening after the operation(loosening group),and 104 patients did not have early tibial component loosening after the operation(non-loosening group).Multivariate logistic regression was used to analyze the influencing factors for developing early tibial component loosening after UKA in the elderly patients with osteoporosis.A nomogram model was constructed based on the independent predictors and was internally validated by using Bootstrap(1 000 iterations),and the prediction efficacy of the nomogram model for developing early tibial component loosening after UKA in the elderly patients with osteoporosis was evaluated by using receiver operating characteristic(ROC)curve.Results Compared with those in the non-loosening group,the maximum total point motion(MTPM)measured by radiostereometric analysis(RSA)was significantly increased(P＜0.05),and the volumetric bone mineral density(vBMD)of proximal tibia measured by quantitative computed tomography(QCT)was significantly decreased(P＜0.05),and the beta-carboxy-terminal cross-linking telopeptide of type Ⅰ collagen(β-CTX)level was significantly increased in the loosening group(P＜0.05).Multivariate logistic regression analysis showed that MTPM measured by RSA[OR(95％CI)=3.32(2.11-5.21)]and β-CTX[OR(95％CI)=1.13(1.06-1.20)]were independent risk factors for developing early tibial component loosening after UKA(P＜0.05),while the vBMD of proximal tibia measured by QCT[OR(95％CI)=0.63(0.44-0.82)]was an independent protective factor inhibiting development of early tibial component loosening after UKA(P＜0.05).The nomogram model constructed based on the above 3 indicators was verified internally to have good discrimination(C-index=0.785,AUC=0.792),and the decision curve analysis showed that the model had high net clinical benefit within the threshold probability range of 0.15-0.38.Conclusion The nomogram model constructed according to the vBMD of proximal tibia measured by QCT,MTPM measured by RSA and bone resorption indicator β-CTX has good predictive performance and clinical application potential,and can be used for risk assessment of early tibial component loosening and stratified management.