Journal of Forensic Biomechanics

Abstract

Preventative Measures to Reduce Incidence of Handcuff Neuropathy

Geoffrey T Desmoulin*, Marc-André and Theodore E Milner

Neuropathy due to prolonged restraint in handcuffs remains a significant concern because handcuffs can be inadvertently over tightened, placing excess pressure on the superficial radial nerve. Recent modifications in handcuff design have begun to address this issue and warrant further investigation. It was hypothesized that a new handcuff design, which prevented over tightening of handcuffs, would prevent the pressure applied to the superficial radial nerve from exceeding nerve injury risk thresholds. To test this hypothesis we used a physical model of the wrist and superficial radial nerve which allowed measurement of the pressure applied by tightened and artificially loaded handcuffs. Three handcuff designs were tested, one of which was designed to prevent over tightening. Recorded pressure was compared to pressure thresholds for loss of function of the rat tibial nerve, a nerve which is similar in diameter to the human superficial radial nerve.

The results indicate that relatively low levels of force applied by tightened handcuffs produced pressures in the surrogate nerve which exceeded nerve injury risk thresholds in two of the handcuffs but not with the handcuff designed to prevent over tightening. The pressure produced by a given load depended on whether the single strand or the double strand of the handcuff was oriented over the surrogate nerve. The results suggest that handcuff designs which include features to prevent over tightening can significantly reduce the risk of injury to the superficial radial nerve even when handcuff restraints are applied for several hours. However, the results also suggest that struggling in the handcuffs can potentially lead to injury even when the handcuffs are not overly tight.

Published Date: 2023-12-29; Received Date: 2023-11-23