Injury patterns and the role of tendons in protecting neurovascular structures in wrist injuries

Abstract

Purpose

The purpose of this study was to evaluate the anatomical features of injured structures, investigate the protection provided by the specific tendon of each corresponding important neurovascular structure (radial artery, median nerve, and ulnar nerve/artery) and to compare the results among the three categories of wrist injuries.

Methods

This study included 114 patients who underwent primary repair for damaged wrist structures; 40 patients sustained accidental damage without intention (group 1), 40 had self-inflicted damage (group 2), and 34 patients had a stab or penetrating wound caused by a sharp instrument during a conflict or violent event involving another person (group 3). The basic demographic factors, distribution pattern, area, and depth of the injured structures were investigated and compared. The barrier roles of the flexor carpi radialis (FCR) for the radial artery, palmaris longus (PL) for the median nerve, and flexor carpi ulnaris (FCU) for the ulnar nerve were estimated.

Results

In group 1, FCU injury was the most common single-structure injury. In group 2, PL ± median nerve injuries were the most common. Multiple-structure injuries involving more than five structures occurred more frequently in group 3 than in the other groups. FCU ± ulnar nerve injuries were more common in group 3 than in the other groups. Radial-side structures were injured most frequently in group 3, and central-side injuries occurred most frequently in groups 1 and 2. Superficial- and middle-layer injuries occurred at similar frequencies among the three groups. Particularly, deep-layer injuries were most weakly related to group 2 injuries. The barrier effects of the FCR, PL, and FCU were confirmed, respectively.

Conclusions

Wrist soft tissue injuries showed particular patterns of injured structures and depths according to the injury mechanism. These patterns included features such as single-structure injuries and the locations and depths of multiple-structure injuries with or without neurovascular injuries. In addition, the roles of FCR, PL, and FCU in protecting important wrist neurovascular structures were confirmed.

Level of evidence

Therapeutic III

Introduction

Wrist injuries are a major clinical concern for hand surgeons. The causes of the injuries and degree of damage to the anatomical structures are varied [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16]. Particularly, self-inflicted lacerations due to psychological problems show additional features associated with repetition and suicide attempts [3], [4], [5], [6], [7], [8], [9], [11], [13], [14], [15], [16], [17]. The epidemiology, injury patterns, psychological analysis, and method of psychological treatment in self-inflicted wrist injury patients have been reported. Some of these patients develop a “chronic wrist cutter” or “wrist-cutting syndrome” state.

Other than self-inflicted wrist injury, the wrist frequently incurs injuries caused by glass, falls, occupational procedures, traffic accidents, violent behaviour, or grinder/saw injuries. We classified these injury types into the following three categories (Fig. 1): (1) accidental damage without intention to injure (group 1), (2) self-inflicted damage regardless of the intention of a suicide attempt (group 2), and (3) stab or penetrating wounds by a sharp instrument during a conflict or violent event with another person regardless of its legality (group 3).

The purpose of the current study was to evaluate the anatomical features of injured structures and investigate the protection provided by tendons to important neurovascular structures (radial artery, median nerve, and ulnar nerve/artery) and to compare the results among the three categories. Our hypothesis was that statistical analysis of the injury patterns would elucidate features according to the injury mechanism or cause and the role of each tendon in protecting the major neurovascular structures in the wrist against an external slashing force.