Computer-assisted Analysis Of The Morphological Features Of Three-dimensional Reconstruction Of Proximal Humeral Medullary Cavity

Background and Object:Proximal humerus fractures(PHF),the third most common Osteoporotic fractures,which incidence is raised from year to year with population aging.Locking compression plate(LCP)fixation has been widely used in the treatment of PHF because of biomechanical benefit.However,there are some adverse situations existing in some PHF cases.The "intramedullary support+extramedullary fixation" proposed,intramedullary support is a promising treatment because of efficiency and micro-invasion.The suitable shape of impant is the key to osteoporotic fracture treatment,while the shape is diverse in clinic.In this study,using the methods of computer-assisted three-dimensional(3D)reconstruction,we tend to obtain aan antomic shape that is suitable by analyzing the morphological characteristics of the proximal humeri medullary cavity and study the curative effect of anatomical fibular allograft for intramedullary suppot,which could provide morphological evidence to the design of anatomical intramedullary implant and clinical application.Methods:1.The 3D model of proximal humerus was reconstructed in MIMICS software.2.The reference and parameters of measurement was established.3.We then finished the procedure of measurement.4.We read the results of measurement and correlation analysis to get the interpretation.5.Clinical follow-up:104 patients with proximal humeral fractures of the elderly treated with simple LCP fixation(61 cases)and LCP combined with allogeneic fibula(43 cases).The long-term efficacy and complication rate were compared between two groups.The follow-up evaluation indicators included:Constant-Murley score(CMS),DASH score,UCLA score,ROM score,VAS score and postoperative radiologic evaluation.Results:1.The proximal humeral medullary cavity was gradually expanded in all sections with aging and bone loss while the upper section expanded much more obviously.2.There were significant differences in the parameters measurements of medullary cavity,eortical bone area and transition zone as gender difference.3.The supporting angle was(44.95±1.95)°.4.There is a correlation between the change of the medial medullary offset and the axial displacement(R>0.8).5.There is a correlation among the parameters of medullary cavity,cortical bone area and transition zone.6.There was no statistical difference between the two groups at the baseline level(P>0.05).There was no statistical difference between the two groups in fractures healed time after operation(P>0.05).The differences in the height loss of humeral heads and the change of neck-shaft angles between the two groups were statistically significant(P<0.05).The difference of the rate of complications in two groups was statistically significant(P<0.05).The differences in the postoperative function evaluations between the two groups were statistically significant(P<0.05).There was no statistical difference between the two groups in the VAS score(P>0.05).Conclusion:1.With aging and bone loss,the proximal humeral medullary cavity expanded in upwards and inwards directions,especially in the head-and-neck.2.The proximal humeral medullary cavity expanded toward the glenohumeral joint like the bell of saxophone while the cortical bone thickness decreased.3.Patients treated by LCP with intramedullary anatomical fibular allograft have a better functional outcome and a lower complication rate comparted to LCP alone for older patients with displaced proximal humerus fractures.