Z-effect after intramedullary nailing systems for trochanteric femur fractures

Purpose： The aim of this study was to investigate the incidence of Z-effect after dual lag screw intramedullary nailing systems and risk factors contributing to this effect. We hypothesized that long nails provide more neck strength due to a longer lever than short nails and are therefore less likely to develop a misbalance of a higher head compressive strength than neck compressive strength, Methods： In this retrospective cohort study 103 patients treated operatively with a dual lag screw intramedullary nailing device for （sub）trochanteric hip fracture were included, We analysed patient charts regarding patient and operation characteristics. Furthermore we conducted radiologic mea- surements within the 2-year follow-up period to investigate the quality of fracture fixation, implant failure and predictors for Z-effect. The re-operation risk was investigated with multivariate regression analysis, Results： The incidence of （reversed） Z-effect in this study was 9% （n 80）; 6 out of 7 Z-effects occurred in the short nail group, which was not significant. Patients who were treated with a long nail had a significant larger number of complications in comparison with the short nail group （median 2 vs 0,5, p = 0.001）. The long nail group received more often erythrocytes blood transfusions （82% vs 31%, p 〈 0.01） and had a longer hospital stay （13 vs 21 days, p 〈 0.05）. Migration of lag screws （p 〈0.05） and unstable fracture type （p 〈 0.05）, were risk factors for re-operation. The re-operation rate within 2 year after surgery was 21%, of which one fourth was due to a Z-effect. Conclusion： The nail length was not associated with the development of a Z-effect. Migration of lag screws after intramedullary nailing is common and a risk factor for re-operation.

Thirty-day mortality of patients with hip fracture during COVID-19 pandemic and pre-pandemic periods:A systematic review and metaanalysis

BACKGROUND Timely intervention in hip fracture is essential to decrease the risks of perioperative morbidity and mortality.However,limitations of the resources,risk of disease transmission and redirection of medical attention to a more severe infective health problem during coronavirus disease 2019(COVID-19)pandemic period have affected the quality of care even in a surgical emergency.AIM To compare the 30-d mortality rate and complications of hip fracture patients treated during COVID-19 pandemic and pre-pandemic times.METHODS The search of electronic databases on 1st August 2020 revealed 45 studies related to mortality of hip fracture during the COVID-19 pandemic and pre-pandemic times.After careful screening,eight studies were eligible for quantitative and qualitative analysis of data.RESULTS The pooled data of eight studies(n=1586)revealed no significant difference in 30-d mortality rate between the hip fracture patients treated during the pandemic and pre-pandemic periods[9.63%vs 6.33%;odds ratio(OR),0.62;95%CI,0.33,1.17;P=0.14].Even the 30-d mortality rate was not different between COVID-19 non-infected patients who were treated during the pandemic time,and all hip fracture patients treated during the pre-pandemic period(OR,1.03;95%CI,0.61,1.75;P=0.91).A significant difference in mortality rate was observed between COVID-19 positive and COVID-19 negative patients(OR,6.99;95%CI,3.45,14.16;P<0.00001).There was no difference in the duration of hospital stay(OR,-1.52,95%CI,-3.85,0.81;P=0.20),overall complications(OR,1.62;P=0.15)and incidence of pulmonary complications(OR,1.46;P=0.38)in these two-time frames.Nevertheless,the preoperative morbidity was more severe,and there was less use of general anesthesia during the pandemic time.CONCLUSION There was no difference in 30-d mortality rate between hip fracture patients treated during the pandemic and pre-pandemic periods.However,the mortality risk was higher in COVID-19 positive patients compared to COVID-19 negative patients.There was no difference in time to surgery,complications and hospitalization time between these two time periods.