Why off-the-shelf clavicle plates rarely fit: anatomic analysis of the clavicle through statistical shape modeling

Abstract

Background The clavicle presents a large variability in its characterizing sigmoid shape. Prominent and nonproperly fitting fixation plates (FP) cause soft tissue irritation and lead to hardware removal. It is therefore key in FP design to account for shape variations. Statistical shape models (SSMs) have been built to analyze a cluster of complex shapes. The goal of this study was to describe the anatomical variation of the clavicle using SSMs. Methods Two different SSMs of the clavicle were created and their modes of variation were described. One model contained 120 left male and female clavicles. The other model consisted of 76 left and corresponding right clavicles, 41 originating from men and 35 from women. Results The model of 120 left clavicles showed that 10 modes of variation are necessary to explain 95% of the variation. The most important modes of variation are the clavicle length, inferior-superior bow, and medial and lateral curvature. Statistically significant differences between male and female clavicles were seen in length, sigmoid shape, and medial curvature. Comparison in men between left and right revealed significant differences in length and medial curvature. For women, a statistically significant difference between left and right was only seen in the length. Conclusion Although the operative treatment of displaced midshaft clavicular fractures has clear benefits, the variable anatomy of the clavicle often makes it challenging for the surgeon to make the plate fit adequately. Based on the identified variability in the clavicle's anatomy, it seems unlikely that a clavicle plating system can fit the entire population.

Anatomical Variation of the Tibia – a Principal Component Analysis

“…Thirdly, these corresponding points are input for the N-ICP-T registration algorithm described by Amberg et al . 18,21 . After performing the non-rigid registration, all tibiae were aligned using a Procrustes analysis and PCA was performed in Matlab (Mathworks, USA).…”

“…Secondly, the generalization was calculated. This number expresses how well a random tibia can be described with the SSM, by calculating the average distance between the original tibia mesh and the mesh obtained by the SSM 18 .…”

“…In an era of personalized medicine, this allows us to strive for the best implant fit for every patient. Statistical shape models (SSM) are promising tools for displaying these variations within a population 18 . Therefore, we aimed to provide a better insight into the anatomical variations of the tibia and particularly the tibial plateau by analyzing the components of the SSM that we created.…”

The variance of clavicular surface morphology is predictable: an analysis of dependent and independent metadata variables

“…The variability in clavicle anatomies is well reported in literature and has also been investigated by means of principal component analysis. 6 , 13 , 14 , 23 These analyses showed that the major source of variability (PC1: 70.5% 6 -79% 13 ) is the CL. The large overall anatomic variability of the clavicle is also visible in the reported parameters of this study.…”

Computer tomographic analysis of anatomic characteristics of the ulna – essential parameters for preshaped implants

“…The threshold of 700 Hounsfield units for the corticocancellous interface is an empirical chosen value, which may not exactly correlate with the density of cortical bone in living humans [22]. An anatomic analysis of the same patient collective with statistical shape modeling as described for other bones is planned to validate our manually acquired results [30][31][32]. Based on the acquired data, a novel intramedullary anatomically preshaped implant could be developed and successfully tested in a biomechanical study and on cadaveric bones.…”