Impact of Design on Force between Flexor Tendons and Distal Radius Volar Plates

Study of the position of six volar locking plates for distal radius fracture relative to the watershed line

INTRODUCTION

Volar plate malpositioning in the treatment of distal radial fracture can lead to tendinitis or even tendon tear, especially when the plate position is very distal. We studied the impact of design on plate position in the distal radius. The primary aim was to compare the position of six volar wrist plates relative to the watershed line using the Soong classification. The secondary objectives were to assess the epidemiology of volar locking plate fixation within the administrative Département of Finistère (northwestern France) and to study whether the type of fracture played a role in plate position.

HYPOTHESIS

The plate design itself influences positioning relative to the watershed line on the Soong classification.

MATERIALS AND METHODS

A total of 2723 volar locking plate fixation cases were analyzed and categorized according to the Soong classification. Plates used were divided into six groups based on design: Zimmer Biomet®, Newclip Technics®, Stryker®, Synthes®, Medartis® and Medartis® Footprint. The number of Soong 0 + 1 plates (i.e., plates graded 0 and 1 taken together) was determined for each design, then compared using the Marascuilo procedure with a significance level of α = 0.05.

RESULTS

On the Marascuilo procedure, we found significant differences in the number of Soong grade 0 + 1 plates. The Zimmer Biomet and Newclip Technics® plates were significantly more often proximal to the watershed line than the Synthes and Medartis Footprint plates. Plate position with the Medartis® design was significantly more proximal to the watershed line than for its companion design, the Medartis® Footprint plate. The rate of volar locking plate fixation of distal radial fractures over the past 10 years increased in Finistère. Also, the type of fracture affected the choice of plate when different designs were available within a hospital center (Medartis® Footprint plate used in 2R3A fractures).

CONCLUSION

Our study highlights a significant difference in volar locking plate position relative to the watershed line between the various models available. Plate design is a deciding factor when treating distal radial fracture, to avoid impingement when implant removal is not routinely planned.

LEVEL OF EVIDENCE: 3

Analysis of risk factors associated with flexor pollicis longus injury after volar plating of distal radius fractures

Objective

This study was performed to analyze the risk factors associated with flexor pollicis longus (FPL) attrition or rupture after volar plating of distal radius fractures.

Methods

Three hundred thirty-eight patients with distal radius fractures were included in this retrospective study. Univariate analysis and multivariate logistic regression analysis were performed to predict risk factors.

Results

Univariate analysis showed that sex, volar tilt, the Soong grade, the plate-to-critical line distance (PCLD), the plate-to-volar rim distance (PVRD), and the time of plate removal were significantly associated with FPL attrition or rupture. Multivariate logistic regression analysis demonstrated that decreased volar tilt, Soong grade 2, PCLD of >2 mm, PVRD of <3 mm, and plate removal at ≥1 year were the risk factors significantly associated with FPL attrition or rupture.

Conclusions

Reduced volar tilt, Soong grade 2, PCLD of >2 mm, and PVRD of <3 mm appear to be risk factors that are significantly associated with FPL attrition or rupture. The findings of this study also suggest that the risk of tendon rupture is lower if a Soong grade 2 plate is removed, the PCLD is >2 mm, the PVRD is <3 mm, or reduced volar tilt is achieved earlier (at <1 year).