Interindividual anatomical variations affect the plate-to-bone fit during osteosynthesis of distal radius fractures

Anatomic variability of the human femur and its implications for the use of artificial bones in biomechanical testing

Aside from human bones, epoxy-based synthetic bones are regarded as the gold standard for biomechanical testing os osteosyntheses. There is a significant discrepancy in biomechanical testing between the determination of fracture stability due to implant treatment in experimental methods and their ability to predict the outcome of stability and fracture healing in a patient. One possible explanation for this disparity is the absence of population-specific variables such as age, gender, and ethnicity in artificial bone, which may influence the geometry and mechanical properties of bone. The goal of this review was to determine whether commercially available artificial bones adequately represent human anatomical variability for mechanical testing of femoral osteosyntheses. To summarize, the availability of suitable bone surrogates currently limits the validity of mechanical evaluations of implant-bone constructs. The currently available synthetic bones neither accurately reflect the local mechanical properties of human bone, nor adequately represent the necessary variability between various populations, limiting their generalized clinical relevance.

Three-dimensional imaging of the distal radius with reference to volar locking plate surgery

BACKGROUND

The watershed line is widely accepted as the distal limit of the volar locking plate (VLP); however, the VLP placement could vary depending on the plate contour and morphology of the distal radius. The aim of this study was to investigate the morphology of the distal radius and VLP fitting using 3D images.

HYPOTHESIS

We hypothesized that attachment of the VLP would affect the contour of the volar prominence of the distal radius.

PATIENTS AND METHODS

Variable-angle LCP two-column volar distal radius Plate 2.4 and 16 formalin-fixed cadavers were studied. The plate and forearm were scanned using a computed tomography scanner. The plate was fixed to the radial shaft in the most distal position without flexor pollicis longus tendon contact. Postero-antero and lateral radiographs were obtained using fluoroscopy. Postero-antero radiographs were superimposed on a 3D image of the distal radius. The virtual plate was attached to the distal radius in the computer simulations and the plate was adjusted in the sagittal plane. In the postero-antero radiographs, the distance between the plate and distal end of the radius (DPR) was measured. In the sagittal plane, the height of the volar lunate facet (VLF) and the plate-to-bone distance of each locking screw hole was measured. The volar cortical angle (VCA) was measured as the angle formed by a line drawn along the volar surface and a line drawn on the radial shaft on the sagittal plane at each locking screw plane.

RESULTS

A significant correlation was observed between the height of the VLF and the DPR and between the height of the VLF and the VCA. The plate-to-bone distance at the ulnar screw hole was significantly smaller than that of the other screw holes.

DISCUSSION

Our study revealed that the higher the VLF, the more proximal is the VLP. The plate fits on the bone surface at the ulnar side, whereas the radial side has more space between the plate and bone.

LEVEL OF EVIDENCE

III, diagnostic Level.

Analysis of the Curvature and Morphologic Features of the Lumbar Vertebral Endplates Through the Transverse Section: A Radioanatomical Study

BACKGROUND

Knowledge concerning the curvature of the vertebrae through the transverse section is of clinical significance. However, relevant reports are scarce. This study investigated the features based on the cross-sections of lumbar vertebral endplates to provide information for clinical practice.

METHODS

Computed tomography images of 78 subjects were retrospectively reviewed. The geometric morphometrics was performed, and the curvature of the vertebral endplates was calculated by the self-written MATLAB algorithm. The principal component analysis, the canonical variate analysis, the discriminant function analysis, and the Mann-Whitney U test were performed. Statistical significance was set at P < 0.05.

RESULTS

No gender difference was found. In contrast, a morphologic difference was found between the superior and inferior lumbar vertebral endplates and between different segments. More specifically, the shape of the endplates gradually changes from the renal shape at superior L1 to the shell-like shape at inferior L5. The mean curvature values of the lateral anterior border were all around 0.60 cm^-1, whereas the mean curvature values of the lateral posterior borders range from 0.66 to 1.09 cm^-1 from L1 to L5. From L1 to L3, the mean and maximum curvature of the lateral posterior superior vertebral endplates decrease. The trend could also be found on the lateral posterior border of the inferior endplates from L1 to L3.

CONCLUSIONS

The current study described morphologic variations and curvature of the lumbar vertebral endplates, which have not been reported previously. The different curvature distribution could provide important information for surgeons and manufacturers.

Interpretations of the Term "Watershed Line" Used as Reference for Volar Plating

Objective  The objective of this systematic review is to provide an overview of all interpretations of the definition of the watershed line used in literature. Methods  The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were followed for this review. A comprehensive search was performed for definitions of the watershed line given in literature. A total of 32 studies giving an explicit interpretation of the definition of the watershed line or anatomical reference for plate positioning in writing and/or imaging were included. Results  In 32 studies, we found eight different landmarks used to refer to the watershed line or correct plate positioning. Five studies used two different soft tissue landmarks. Six different bony landmarks were described in 24 studies. These could further be subdivided into three anatomical interpretations, described in seven studies, in which the term "watershed line" is explained as a distinguishable anatomical line, and two surgical interpretations, described in 15 studies, which are purely reflecting the optimal location of the volar plate. One interpretation of the watershed line described in two studies combined both anatomical and surgical landmarks. Conclusion  The (mis)interpretation of the definition of the term "watershed line" as described by Orbay is subject to the type of landmarks and purpose used: soft tissue or bony landmarks and an anatomical or a surgical purpose. A clear distinction can be made between interpretations using bony landmarks, as the true watershed line is defined and definitions using soft tissue landmarks, which might represent the reference points surgeons use in clinical practice.

A systematic review of volar locking plate removal after distal radius fracture

BACKGROUND

Indication of volar locking plate (VLP) removal after bony healing of distal radius fracture (DRF) is controversial. Studies with various range of removal rate were reported. The purpose of this systematic review was to investigate the frequency and the reasons of hardware removal over the world. We hypothesized that more frequent VLP removal contribute to better clinical outcomes.

METHODS

The authors searched all available literature in the PubMed and EMBASE databases for articles reporting on outcomes of treatment using VLP for DRF. Data collection included hardware removal rate, complication rate, clinical and radiological outcomes. We analyzed correlation between hardware removal rate with clinical and radiological outcomes.

RESULTS

A total of 3472 articles were screened, yielding 52 studies for final review. The mean hardware removal rate was 9%, ranging from 0 to 100%. The mean removal rate in studies from France, Norway, Japan, and Belgium was as high as 19%. The mean removal rate in studies from the US was low (3%). The most frequent reasons for extraction were routine removal (22%), tendon irritation or tenosynovitis (14%), hardware problem (14%), and patient' request (13%). Although routine removal and patient' request were not counted as complication, correlation between removal rate with complication rate was strong (rho=0.64, p<0.001). Correlations between clinical and radiological outcomes were week except for volar tilt (rho=-0.42, p=0.009).

CONCLUSIONS

There was a diversity of removal rate and reasons in the studies over the world. High frequent VLP removal did not contribute to better clinical outcomes.

Treatment of Intra-articular Distal Radius Fractures

This review of current literature discusses the morphology of the volar aspect of the distal radius; the surgical procedure, arthroscopic findings, and clinical results of a plate presetting and arthroscopic reduction technique for acute intra-articular fractures; and a novel simulation guidance system for malunited intra-articular fractures. Classification of intra-articular distal radius fractures is also discussed, focusing on central depression fracture fragments, associated soft tissue injuries, and results for measuring scapholunate distances at different sites. Problems of the distal radioulnar joint are reviewed, in particular, functional outcomes of the authors' prospective cohort study on unstable intra-articular fractures involving the distal radioulnar joint.

Volar Distal Radius Anatomy Applied to the Treatment of Distal Radius Fracture

Volar locking plate (VLP) fixation has become the standard surgical treatment for distal radius fractures. However, flexor tendon rupture is one of the major complications following volar plating. This detailed review on the anatomy and morphology of the volar distal radius might facilitate appropriate placement of the volar plate and thereby avoid flexor tendon rupture. We introduce safe and secure VLP fixation along standard surgical procedures to avoid complications based on anatomy of the volar surface of the distal radius.