Jnl Wrist Surg 2019; 08(01): 061-065
DOI: 10.1055/s-0038-1673344
Scientific Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

The Twist X-Ray: A Novel Test for Dynamic Scapholunate Instability

Sheena K. Sikora
1  Division of Hand Surgery, Department of Orthopaedic Surgery, Dandenong Hospital, Monash University, Melbourne, Australia
,
Stephen K. Tham
1  Division of Hand Surgery, Department of Orthopaedic Surgery, Dandenong Hospital, Monash University, Melbourne, Australia
2  Victorian Hand Surgery Associates, Melbourne, Victoria, Australia
,
Jason N. Harvey
1  Division of Hand Surgery, Department of Orthopaedic Surgery, Dandenong Hospital, Monash University, Melbourne, Australia
3  Orthosports Victoria, Epworth Hospital, Melbourne, Victoria, Australia
,
Marc Garcia-Elias
4  Institut Kaplan, Barcelona, Spain
,
Tony Goldring
5  Victoria House Medical Imaging, Melbourne, Victoria, Australia
,
Andrew H. Rotstein
5  Victoria House Medical Imaging, Melbourne, Victoria, Australia
,
Eugene T. Ek
1  Division of Hand Surgery, Department of Orthopaedic Surgery, Dandenong Hospital, Monash University, Melbourne, Australia
6  Melbourne Orthopaedic Group, Melbourne, Victoria, Australia
7  Department of Surgery, Monash Medical Centre, Monash University, Australia
› Author Affiliations
Further Information

Publication History

18 September 2017

27 August 2018

Publication Date:
03 October 2018 (online)

Abstract

Background Scapholunate instability (SLI) is the most common form of carpal instability. Early detection of SLI is imperative as early reconstructive procedures can potentially prevent the natural history of progressive degenerative arthritis. After wrist arthroscopy, magnetic resonance imaging (MRI) remains the next best noninvasive diagnostic option; however, access still remains costly and is often limited in many health care systems worldwide. In this article, we describe a novel device that allows for dynamic X-rays to be taken, accentuating the scapholunate (SL) widening.

Description of Technique Twist X-ray views are generated by the patient clenching a device that combines the standard clenched fist views with ulnar deviation and supination. The test is easy to perform and functions by combining a higher grip force with the ulnar deviation and pronation effects of the extensor carpi ulnaris tendon, thus accentuating the SL gap in dynamic instability.

Patients and Methods We present a series of four patients with dynamic SLI and compare the findings of the Twist X-rays with conventional wrist X-rays series, including standard anteroposterior, lateral, radial, and ulna deviation, clenched fist, and pencil grip views.

Results In all the four patients, there was substantial dynamic SL widening. The SL interval increased from a mean of 1.8 mm (range: 1.5–2.8) on posteroanterior X-rays to 6.3 mm (range: 4.6–8.2) with the Twist views. Interestingly, on the pencil grip view, the mean widening was only 1.5 mm (range: 1–2.8 mm).

Conclusion The authors describe a novel device that allows for improved detection of dynamic SL ligament instability when performing stress X-ray views of the wrist.

Level of Evidence This is a Level IV study.

Ethical Approval

The ethical approval was granted by Avenue Hospital Human Ethics Approval, Trial No. 199 (29/4/16).