252 Injury, 9. 252-253 Printed in Great Britain

Wrinkle Corner

A compact goniometer for the hand

Roger Austin 1 eicester Royal Infirmary

ACCURATE measurement of the range of move- ment of the finger joints may be difficult, par- ticularly when flexion is nearly full and the pulp of the fingertip is buried in the palm. Gonio- meters of various types are available but many of them are complicated and cumbersome. An effective instrument can be constructed from the type of plastic protractor and set-square found in a child’s geometry set (Fig. 1).

The protractor is cut off to allow measurement to 110”. The measuring arm is cut from the set square or from another convenient piece of plastic material and one end is bevelled. The two

Fig. 1. The materials are easily obtained and assem- bled. Note the short arm and bevelled end.

pieces are assembled with a small nut and bolt from a Meccano set. The hole in the protractor is ‘undersized’ so that the bolt grips while the nut acts as a lock.

The instrument is light and compact. It is easily held between the tips of the thumb and middle finger while the index finger adjusts the arm to fit over the joint being measured. Only one hand is required and the bevelling of the measuring arm allows good apposition of the edges to the finger even when the pulp is buried in the palm. It is not necessary to hold or manipulate the other fingers and the only variation from the normal gripping action is that the thumb needs to be extended by the patient to allow better access to the distal interphalangeal joints (Fig. 2). Measurement of the movement at the proximal interphalangeal and metacarpophalangeal joints is straight- forward. Hyperextension is measured from the palmar surface.

Fig. 2. The bevelled arm allows accurate measurement of flexion at the distal joint even in this position.

Requestsfor reprints should be addressed m: MI R. T. Austin, Consultant Orthopaedic Surgeon, L&ester Royal Infirmary, L&ester.