A Herbert screw is an instrument is used in internal fixation of unstable scaphoid fracture. It is a headless screw with thread along its entire length. The two halves of the screw have a different pitch though, which causes compression of the fracture.
Unstable scaphoid fractures which include:
- displacement >1 mm
- scapholunate angle >60o
- radiolunate angle >15o
- ineffective in long standing nonunion scaphoid fractures
- 1. Parajuli NP, Shrestha D, Dhoju D et-al. Scaphoid fracture: functional outcome following fixation with Herbert Screw. Kathmandu Univ Med J (KUMJ). 2012;9 (36): 267-73. Pubmed citation