Reliability of pain pressure threshold algometry in persons with conservatively managed wrist fractures.

Abstract

Wrist fracture is a common injury in Norway. Pressure algometry is widely used to quantify patients' pain threshold in various anatomical locations. The aim of this study was to explore the reliability of pain pressure threshold (PPT) algometry in persons with conservatively managed distal radius fractures. In this cross-sectional study, three raters (A, B, and C) tested the PPT of participants (18-97years of age) with a unilateral distal radius fracture after removal of the cast. The raters conducted two measurements of both wrists. Intrarater reliability was examined in 75, 50, and 25 participants by Raters A, B, and C, respectively. Interrater reliability was tested in 50 and 25 participants by Rater Pairs A-B and A-C, respectively. Relative reliability was calculated with intraclass correlation coefficient (ICC1.1 ) and absolute reliability using within-subject standard deviation (Sw ). There was a significant difference in the PPT between the participants' injured and noninjured wrists (p<.0001). The mean PPT was 29% lower in the injured than in the noninjured wrists, 175kPa (SD±62) versus 248kPa (SD±83). Intrarater reliability (A) of PPT algometry was better in injured wrists than in noninjured wrists (ICC1.1 =0.825 vs. 0.765 and Sw =27 vs. 43kPa). Similarly, interrater reliability of PPT algometry was better in injured wrists than in noninjured wrists. In injured wrists, the interrater reliability of PPT algometry between Raters A and B was 0.617 (ICC1.1 ) and Sw was 51kPa, and between Raters A and C, the interrater reliability was 0.706 (ICC1.1 ) and Sw was 48kPa. PPT algometry is a useful measurement tool with acceptable reliability and thus suitable for monitoring and quantifying pain in persons with conservatively managed wrist fractures. To be more certain that a change has occurred, the same rater should perform the measurements.