Biomechanical evaluation of the ligamentous stabilizers of the scaphoid and lunate: part III

Abstract

Purpose: This study continued our previous investigations of the ligaments stabilizing the scaphoid and lunate in which we examined the scapholunate interosseous ligament, the radioscaphocapitate, and the scaphotrapezial ligament. In this current study, we examined the effects of sectioning the dorsal radiocarpal ligament, dorsal intercarpal ligament, scapholunate interosseous ligament, radioscaphocapitate, and scaphotrapezial ligaments. In the current study, the scapholunate interosseous ligament, radioscaphocapitate, and scaphotrapezial ligaments were sectioned in a different order than performed previously.

Methods: Three sets of 8 cadaver wrists were tested in a wrist joint motion simulator. In each set of wrists, only 3 of the 5 ligaments were cut in specific sequences. Each wrist was moved in continuous cycles of flexion-extension and radial-ulnar deviation. Kinematic data for the scaphoid and lunate were recorded for each wrist in the intact state, after the 3 ligaments were sectioned in various sequences and after the wrist was moved through 1,000 cycles of motion.

Results: Dividing the dorsal intercarpal or scaphotrapezial ligaments did not alter the motion of the scaphoid or lunate. Dividing the dorsal radiocarpal ligament alone caused a slight statistical increase in lunate radial deviation. Dividing the scapholunate interosseous ligament after first dividing the dorsal intercarpal, dorsal radiocarpal, or scaphotrapezial ligaments caused large increases in scaphoid flexion and lunate extension.

Conclusions: Based on these findings, we concluded that the scapholunate interosseous ligament is the primary stabilizer and that the other ligaments are secondary stabilizers of the scapholunate articulation. Dividing the dorsal radiocarpal, dorsal intercarpal, or scaphotrapezial ligaments after cutting the scapholunate interosseous ligament produces further changes in scapholunate instability or results in changes in the kinematics for a larger portion of the wrist motion cycle.

Figure 1

Average scaphoid flexion and extension as a function of wrist flexion and extension in the intact wrist and after sequential ligamentous sectioning in the first group of arms. The graph represents the motion of the scaphoid during a complete cycle of wrist motion from flexion to extension to flexion. Flexion is positive.

Figure 2

Average lunate flexion and extension as a function of wrist flexion and extension in the intact wrist and after sequential ligamentous sectioning in the first group of arms. The graph represents the motion of the lunate during a complete cycle of wrist motion from flexion to extension to flexion. Flexion is positive.

Figure 3

Average minimum distance between the scaphoid and lunate in the intact wrist and after sequential sectioning in the first group of arms. The graph represents the portion of the wrist motion cycle as the wrist is moving from wrist flexion to extension.

Figure 4

Average minimum distance between the scaphoid and lunate in the intact wrist and after sequential ligament sectioning in the first group of arms. The graph represents the portion of the wrist motion cycle as the wrist is moving from radial to ulnar deviation.

Figure 5

Average scaphoid radial and ulnar deviation as a function of wrist flexion and extension in the intact wrist and after sequential ligamentous sectioning in the second group of arms. The graph represents the motion of the scaphoid during a complete cycle of wrist motion from flexion to extension to flexion. Flexion and radial deviation are positive.

Figure 6

Average lunate radial and ulnar deviation as a function of wrist flexion and extension in the intact wrist and after sequential ligamentous sectioning in the second group of arms. The graph represents the motion of the lunate during a complete cycle of wrist motion from flexion to extension to flexion. Flexion and radial deviation are positive.

Figure 7

Average scaphoid flexion and extension as a function of wrist radial and ulnar deviation in the intact wrist and after sequential ligamentous sectioning in the second group of arms. The graph represents the motion of the scaphoid during a complete cycle of wrist motion from radial deviation to ulnar deviation to radial deviation. Flexion and radial deviation are positive. The irregular ends of the curves are the result of including only the data points common to all 8 arms during a range of motion. Some arms continued beyond the shown end points.

Figure 8

Average minimum distance between the scaphoid and lunate in the intact wrist and after sequential ligamentous sectioning in the second group of arms. The graph represents the portion of the wrist motion cycle as the wrist is moving from wrist flexion to extension.

Figure 9

Average scaphoid flexion and extension as a function of wrist flexion and extension in the intact wrist and after sequential ligamentous sectioning in the third group of arms. The graph represents the motion of the scaphoid during a complete cycle of wrist motion from flexion to extension to flexion. Flexion is positive.

Figure 10

Average scaphoid flexion and extension as a function of wrist radial and ulnar deviation in the intact wrist and after sequential ligamentous sectioning in the third group of arms. The graph represents the motion of the scaphoid during a complete cycle of wrist motion from radial deviation to ulnar deviation to radial deviation. Flexion and radial deviation are positive. The irregular ends of the curves are the result of including only the data points common to all 8 arms during a range of motion. Some arms continued beyond the shown end points.

Figure A1

Average scaphoid radial and ulnar deviation as a function of wrist flexion and extension in the intact wrist and after sequential ligamentous sectioning in the first group of arms. The graph represents the motion of the scaphoid during a complete cycle of wrist motion from flexion to extension to flexion. Flexion and radial deviation are positive.

Figure A2

Average lunate radial and ulnar deviation as a function of wrist flexion and extension deviation in the intact wrist and after sequential ligamentous sectioning in the first group of arms. The graph represents the motion of the lunate during a complete cycle of wrist motion from flexion to extension to flexion. Flexion and radial deviation are positive.

Figure A3

Average scaphoid flexion and extension as a function of wrist radial and ulnar deviation in the intact wrist and after sequential ligamentous sectioning in the first group of arms. The graph represents the motion of the scaphoid during a complete cycle of wrist motion from radial deviation to ulnar deviation to radial deviation. Flexion and radial deviation are positive. The irregular ends of the curves are the result of including only the data points common to all 8 arms during a range of motion. Some arms continued beyond the shown end points.

Figure A4

Average scaphoid radial and ulnar deviation as a function of wrist radial and ulnar deviation in the intact wrist and after sequential ligamentous sectioning in the first group of arms. The graph represents the motion of the scaphoid during a complete cycle of wrist motion from radial deviation to ulnar deviation to radial deviation. Flexion and radial deviation are positive. The irregular ends of the curves are the result of including only the data points common to all 8 arms during a range of motion. Some arms continued beyond the shown end points.

Figure A5

Average lunate flexion and extension as a function of wrist radial and ulnar deviation in the intact wrist and after sequential ligamentous sectioning in the first group of arms. The graph represents the motion of the lunate during a complete cycle of wrist motion from radial deviation to ulnar deviation to radial deviation. Flexion and radial deviation are positive. The irregular ends of the curves are the result of including only the data points common to all 8 arms during a range of motion. Some arms continued beyond the shown end points.

Figure A6

Average lunate radial and ulnar deviation as a function of wrist radial and ulnar deviation in the intact wrist and after sequential ligamentous sectioning in the first group of arms. The graph represents the motion of the lunate during a complete cycle of wrist motion from radial deviation to ulnar deviation to radial deviation. Flexion and radial deviation are positive. The irregular ends of the curves are the result of including only the data points common to all 8 arms during a range of motion. Some arms continued beyond the shown end points.

Figure A7

Average scaphoid flexion and extension as a function of wrist flexion and extension in the intact wrist and after sequential ligamentous sectioning in the second group of arms. The graph represents the motion of the scaphoid during a complete cycle of wrist motion from flexion to extension to flexion. Flexion is positive.

Figure A8

Average lunate flexion and extension as a function of wrist flexion and extension in the intact wrist and after sequential ligamentous sectioning in the second group of arms. The graph represents the motion of the lunate during a complete cycle of wrist motion from flexion to extension to flexion. Flexion is positive.

Figure A9

Average scaphoid radial and ulnar deviation as a function of wrist radial and ulnar deviation in the intact wrist and after sequential ligamentous sectioning in the second group of arms. The graph represents the motion of the scaphoid during a complete cycle of wrist motion from radial deviation to ulnar deviation to radial deviation. Flexion and radial deviation are positive.

Figure A10

Average lunate flexion and extension as a function of wrist radial and ulnar deviation in the intact wrist and after sequential ligamentous sectioning in the second group of arms. The graph represents the motion of the lunate during a complete cycle of wrist motion from radial deviation to ulnar deviation to radial deviation. Flexion and radial deviation are positive.

Figure A11

Average lunate radial and ulnar deviation as a function of wrist radial and ulnar deviation in the intact wrist and after sequential ligamentous sectioning in the second group of arms. The graph represents the motion of the lunate during a complete cycle of wrist motion from radial deviation to ulnar deviation to radial deviation. Flexion and radial deviation are positive.

Figure A12

Average minimum distance between the scaphoid and lunate in the intact wrist and after sequential ligamentous sectioning in the second group of arms. The graph represents the portion of the wrist motion cycle as the wrist is moving from radial to ulnar deviation.

Figure A13

Average scaphoid radial and ulnar deviation as a function of wrist flexion and extension in the intact wrist and after sequential ligamentous sectioning in the third group of arms. The graph represents the motion of the scaphoid during a complete cycle of wrist motion from flexion to extension to flexion. Flexion and radial deviation are positive.

Figure A14

Average lunate flexion and extension as a function of wrist flexion and extension in the intact wrist and after sequential ligamentous sectioning in the third group of arms. The graph represents the motion of the lunate during a complete cycle of wrist motion from flexion to extension to flexion. Flexion is positive.

Figure A15

Average lunate radial and ulnar deviation as a function of wrist flexion and extension deviation in the intact wrist and after sequential ligamentous sectioning in the third group of arms. The graph represents the motion of the lunate during a complete cycle of wrist motion from flexion to extension to flexion. Flexion and radial deviation are positive. The irregular ends of the curves are the result of including only the data points common to all 8 arms during a range of motion. Some arms continued beyond the shown end points.

Figure A16

Average scaphoid radial and ulnar deviation as a function of wrist radial and ulnar deviation in the intact wrist and after sequential ligamentous sectioning in the third group of arms. The graph represents the motion of the scaphoid during a complete cycle of wrist motion from radial deviation to ulnar deviation to radial deviation. Flexion and radial deviation are positive.

Figure A17

Average lunate flexion and extension as a function of wrist radial and ulnar deviation in the intact wrist and after sequential ligamentous sectioning in the third group of arms. The graph represents the motion of the lunate during a complete cycle of wrist motion from radial deviation to ulnar deviation to radial deviation. Flexion and radial deviation are positive. The irregular ends of the curves are the result of including only the data points common to all 8 arms during a range of motion. Some arms continued beyond the shown end points.

Figure A18

Average lunate radial and ulnar deviation as a function of wrist radial and ulnar deviation in the intact wrist and after sequential ligamentous sectioning in the third group of arms. The graph represents the motion of the lunate during a complete cycle of wrist motion from radial deviation to ulnar deviation to radial deviation. Flexion and radial deviation are positive.

Figure A19

Average minimum distance between the scaphoid and lunate in the intact wrist and after sequential ligamentous sectioning in the third group of arms. The graph represents the portion of the wrist motion cycle as the wrist is moving from wrist flexion to extension.

Figure A20

Average minimum distance between the scaphoid and lunate in the intact wrist and after sequential ligamentous sectioning in the third group of arms. The graph represents the portion of the wrist motion cycle as the wrist is moving from radial to ulnar deviation.