Dynamic changes of the transverse carpal arch during flexion-extension of the wrist: Effects of sectioning the transverse carpal ligament The width of the carpal arch, represented in this study by the distance between the tips of two Kirschner wires-one inserted into the trapezium and another into the hook of the hamatewas measured with precision calipers in 21 patients with carpal tunnel syndrome, both before and after sectioning of the transverse carpal ligament and in different wrist positions. With the ligament intact, most of the wrists showed a decrease in the distance in both flexion and extension. The distance increased an average of 11% after sectioning of the transverse carpal ligament. The dynamic behavior of the carpal arch, however, was not substantially modified by this procedure. (J HAND SURG 1992jI7A:I017·9.)

Marc Garcia-Elias, MD, Jose M. Sanchez-Freijo, MD, Josep M. Salo, MD, and Alberto L. Lluch, MD, Barcelona, Spain

The transverse carpal arch is not a rigid structure. There is slight rotational motion between the bones of the distal carpal row as the wrist moves. I, 2 The transverse dimensions of the carpal arch also appear to change from wrist flexion to extension.l" The magnitude and direction of those changes, however, remain unclear. This study was designed to clarify whether sectioning of the transverse carpal ligament (TCL) modifies the dynamic behavior of the carpal arch. The distance between the tips of two Kirschner (K-)wires inserted into the trapezium and the hook of the hamate, with the wrist in flexion, neutral, and extension positions, before and after division of the TCL, was measured in patients with carpal tunnel syndrome.

From the Department of Orthopedic Surgery, Hospital General de Catalunya, Sant Cugat del Valles, the Department of Orthopedic Surgery, Hospital General de Manresa, Unitat Assistencial Sant Joan de Deu Manresa; and the Department of Orthopedic Surgery Hospital Santa Creu i Sant Pau, Barcelona. Received for publication Oct. 4, 1990; accepted in revised form Sept. 27,1991. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: M. Garcia-Elias, MD, Hospital General de Catalunya, La Gomera sin, 08190 Sant Cugat del Valles, Barcelona, Spain.

3/1/35023

Material and methods Twenty-one patients (19 women and 2 men ranging in age from 30 to 73 years with a mean of 48 years) with idiopathic carpal tunnel syndrome requiring surgery agreed to participate in this study. Surgery was always performed with the patient under axillary block anesthesia, and the limb was exsanguinated with the use of an Esmarch bandage. The incision to the TCL was a 4 cm straight incision in line with the ring finger, as suggested by Lluch."? Guyon's canal was explored, and its contents were protected. Before release of the TeL, the tip of the hook of the hamate was localized and an 0.045-inch K-wire was inserted perpendicular to the coronal plane of the hand. Another 0.04S-inch K-wire was inserted percutaneously into the trapezium, parallel to the first wire and also perpendicular to the coronal plane (Fig. 1). The two protruding wires were cut 2 em from the skin. With the wrist resting in neutral position, the distance between the tips of the two wires was measured with sterile precison calipers, accurate up to 0.1 mm. The average of three separate determinations was the value used in this study. Identical measurements were made after the wrist was positioned into full flexion and full extension. Finally, the TCL was sectioned, and all the measurements in neutral, flexion, and extension were repeated. All distances were expressed as a percentage of the distance between the two wires with the wrist in neutral

THE JOURNAL OF HAND SURGERY

1017

1018

The Journal of HAND SURGERY

Garcia-Elias et al.

~

......,

o

20"':

16-

p=O.07

-f -,-,' -----1--

o : - - - - - - - - - - ....c>--..:;. - - - - -- -' ,. ,. p=O.055

-5':

p