Quantifying in vivo scaphoid, lunate, and capitate kinematics using four-dimensional computed tomography.

OBJECTIVE: We aimed to establish a quantitative description of motion patterns and establish test-retest reliability of the four-dimensional CT when quantifying in vivo kinematics of the scaphoid, lunate, and capitate. MATERIALS AND METHODS: We assessed in vivo kinematics of both wrists of 20 healthy volunteers (11 men and 9 women) between the ages of 20 and 40 years. All volunteers performed active flexion-extension and radial-ulnar deviation with both wrists. To test for reliability, one motion cycle was rescanned for both wrists approximately 15 min after the first scan. The coefficient of multiple correlation was used to analyze reliability. When two motion patterns are similar, the coefficient of multiple correlation tends towards 1, whereas in dissimilar motion patterns, it tends towards 0. The root mean square deviation was used to analyze the total motion patterns variability between the two scans. RESULTS: Overall, mean or median coefficient of multiple correlations were higher than 0.86. The root mean square deviations were low and ranged from 1.17° to 4.29°. CONCLUSION: This innovative non-invasive imaging technique can reliably describe in vivo carpal kinematics of uninjured wrists in healthy individuals. It provides us with a better understanding and reference values of carpal kinematics of the scaphoid, lunate, and capitate.

Dynamic assessment of wrist after proximal row carpectomy and 4-corner fusion.

PURPOSE: To investigate the effect of 4-corner fusion (4CF) or proximal row carpectomy (PRC) on wrist motion, strength, and outcome for 2 different cohorts from 2 separate institutions performing either 4CF or PRC for stage 2/3 scaphoid nonunion advanced collapse and scapholunate advanced collapse. METHODS: The researchers assessed 46 subjects (24 4CF and 22 PRC), mean age 54 years, with a flexible electrogoniometer to measure maximum wrist motion and circumduction and compare it with the nonsurgical wrist. We analyzed the shape, size, rate, and smoothness of the circumduction curves. We assessed the maximum grip and sustainability of grip for 60 seconds using a digital grip analyzer. Patient evaluation measure and Michigan Hand Questionnaires measured patient-reported outcomes. RESULTS: Flexion-extension in the surgically treated wrist was 50% of the nonsurgical side after a 4CF and 65% after a PRC. The radioulnar deviation component in circumduction of the surgically treated wrist was similar but markedly decreased after either procedure. The mean area of circumduction of the surgically treated wrist was similar after a PRC and a 4CF but was 30% of the nonsurgical wrist. The center of the circumduction ellipse after a PRC was closer than after a 4CF to the opposite wrist. The orientation of the plane of circumduction was 22° to the vertical flexion-extension plane after a PRC. After a 4CF, the plane was more vertical (9°). The peak grip strength and the area under the force time curve was 80% of the nonsurgical side after a PRC and 60% after a 4CF. The Michigan Hand Questionnaire result was 90% of the score for the nonsurgical hand after a PRC and 75% of score for the nonsurgical hand after a 4CF. CONCLUSIONS: The PRC provided improved flexion-extension with a circumduction curve concentric with the nonsurgical wrist. The 4CF limited extension and ulnar deviation more than did a PRC. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Four-dimensional CT analysis of carpal kinematics: An explorative study on the effect of sex and hand-dominance.

Wrist pathology is often diagnosed by using the contralateral wrist as a comparison of baseline motion and strength. However, recent range of motion studies suggest that females have different carpal motion patterns compared to males and that the dominant carpal bones have different motion patterns. The purpose of this study is to evaluate the effect of sex and hand dominance on in vivo kinematics of the scaphoid, lunate and capitate using four-dimensional computed tomography (4D-CT) analysis in healthy uninjured volunteers. In this prospective study, both wrist of 20 uninjured Caucasian volunteers (11 men and 9 women) were assessed using 4D-CT during active flexion-extension and radial-ulnar deviation. A linear mixed model was used to compare the carpal motion patterns. Sex had no influence on carpal kinematics. Hand-dominance in males did have a significant effect on carpal kinematics. During flexion-extension of the male wrist, more radial-ulnar deviation of the lunate, scaphoid and capitate of the non-dominant hand was seen. During radial-ulnar deviation of the male wrist, radial-ulnar deviation and pro-supination of the lunate was more in the dominant hand. This study provides a better understanding of carpal kinematics and the effect of sex and hand-dominance on the scaphoid, lunate and capitate in uninjured wrists.

Effects of axial load on in vivo scaphoid and lunate kinematics using four-dimensional computed tomography.

This in vivo study investigated the effect of axial load on lunate and scaphoid kinematics during flexion-extension and radial-ulnar deviation of the uninjured wrist using four-dimensional computed tomography. We found that applying axial load to the wrist results in a more flexed, radially deviated and pronated position of the lunate and scaphoid during flexion-extension of the wrist compared with when no load is applied. A larger pronation and supination range of the lunate and scaphoid was seen when the wrist was flexed and extended under axial load, whereas a larger flexion and extension range of the lunate and scaphoid occurred during radial-ulnar deviation of the wrist when axial load was applied.

A four-dimensional-CT study of in vivo scapholunate rotation axes: possible implications for scapholunate ligament reconstruction.

Additional fixation of the palmar scapholunate interosseous ligament has been advocated to improve the long-term results of dorsal scapholunate interosseous ligament reconstruction. To investigate the validity of this approach, we determined normal scapholunate motion patterns and calculated the location of the scapholunate rotation axis. We hypothesized that the optimal location of the scapholunate interosseous ligament insertion could be determined from the scapholunate rotation axis. Four-dimensional computerized tomography was used to study the wrist motion in 21 healthy participants. During flexion-extension motions, the scaphoid rotates 38° (SD 0.6°) relative to the lunate; the rotation axis intersects the dorsal ridge of the proximal pole of the scaphoid and the dorsal ridge of the lunate. Minimal scapholunate motion is present during radioulnar deviation. Since the scapholunate rotation axis runs through the dorsal proximal pole of the scaphoid, this is probably the optimal location for attaching the scapholunate ligament during reconstructive surgery.