Elsevier

The Journal of Hand Surgery

Volume 26, Issue 5, September 2001, Pages 828-832
The Journal of Hand Surgery

Original Communications
The influence of cross-sectional area on the tensile properties of flexor tendons*,**

https://doi.org/10.1053/jhsu.2001.26661Get rights and content

Abstract

Clinicians have long noted substantial variation in the cross-sectional size of flexor tendons in the hand; however, data indicating that surgical repair techniques of lacerated flexor tendons should be altered according to size are unavailable. Our objectives were to evaluate the cross-sectional size differences among tendons within the same hand and to correlate tendon size with tensile mechanical properties after suture repair. Fifty human cadaver flexor digitorum profundus tendons were measured with digital calipers to determine radioulnar and volardorsal diameters. Twenty tendons were used to measure resistance to suture pull-through; tendons were transected at the A2 pulley, and a transverse double-stranded 4–0 Supramid suture (S. Jackson, Inc, Alexandria, VA) was passed through the radioulnar plane of the tendon 1 cm from the transection site. The remaining tendons were transected and repaired by using a modified Kessler repair with double-stranded 4–0 Supramid suture. Both tendon repairs and tendon–suture pull-through specimens were tested to failure in tension by using a material testing machine. Dorsovolar tendon height and tendon cross-sectional area varied significantly between digits, with an average difference of approximately 40% between the values of the smallest (fifth) and largest (third) fingers. Yield and ultimate force determined by pull-through tests of the simple transverse suture correlated positively with tendon radioulnar width. Tensile properties of tendons repaired with a double-stranded modified Kessler repair, however, did not depend significantly on tendon size. These results indicate that the strength of the commonly used Kessler suture technique is not dependent on tendon cross-sectional size within the clinically relevant range of tendons evaluated. (J Hand Surg 2001;26A:828–832. Copyright © 2001 by the American Society for Surgery of the Hand.)

Section snippets

Measurement of cross-sectional dimension

Fifty tendons from 10 fresh-frozen cadaver hands were used. After thawing flexor digitorum profundus and flexor pollicis longus tendons were dissected distally at the insertion site and proximally to the musculotendinous junction. Before excision the tendons were marked at the distal edge of the A2 pulley with the digits in full extension. Width and height of the tendons were measured with digital calipers. These measurements were used to compute tendon cross-sectional area based on an

Results

ANOVA testing indicated that tendon dorsovolar height and cross-sectional area estimated with an elliptical approximation varied significantly between digits (p <.001). There was a 38% difference between mean values of height for the largest (middle finger) and the smallest (little finger) digits and a 42% difference in cross-sectional area (Table 1).

. Mean (±SD) values of flexor digitorum profundus tendon width (radioulnar), height (dorsovolar), and area approximated as an ellipse

DigitFirst

Discussion

We used ex vivo caliper measurements of flexor tendon cross-sectional area to evaluate the range of sizes of flexor digitorum profundus tendons between digits in the same hand. We found a size variation of approximately 40% between the smallest (little finger) and the largest (middle finger) flexor digitorum profundus tendons across specimens. Information on the relative cross-sectional sizes of intrasynovial digital flexor tendons within hands has been heretofore unavailable. The finding that

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*

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: Martin I. Boyer, MD, Department of Orthopaedic Surgery, One Barnes Hospital Plaza, Suite 11300, St Louis, MO 63110.

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