Yohei Kawanishi1, Hisao Moritomo2, Shohei Omokawa1, Tsuyoshi Murase1, Kazuomi Sugamoto1, Hideki Yoshikawa1. 1. Department of Orthopedic Surgery, Osaka University Graduate School of Medicine, Yamada-oka, Suita; Department of Orthopedic Biomaterial Science, Osaka University Graduate School of Medicine, Yamada-oka, Suita; Department of Physical Therapy, Osaka Yukioka College of Health Science, Sojiji, Ibaraki-shi, Osaka; Department of Orthopedics, Nara Medical University, Kitayamato, Ikoma Nara, Japan. 2. Department of Orthopedic Surgery, Osaka University Graduate School of Medicine, Yamada-oka, Suita; Department of Orthopedic Biomaterial Science, Osaka University Graduate School of Medicine, Yamada-oka, Suita; Department of Physical Therapy, Osaka Yukioka College of Health Science, Sojiji, Ibaraki-shi, Osaka; Department of Orthopedics, Nara Medical University, Kitayamato, Ikoma Nara, Japan. Electronic address: moritomo@tcct.zaq.ne.jp.
Abstract
PURPOSE: To examine 3-dimensional carpal alignment and radioscaphoid joint (RSJ) congruity among normal wrists and those with Lichtman stage III Kienböck disease or scapholunate dislocation (SLD). METHODS: We conducted 3-dimensional analysis based on computed tomographic data to compare 10 wrists of stage III Kienböck disease (5 IIIa and 5 IIIb) with 5 normal wrists and 3 wrists with SLD. A markerless bone registration technique was used to investigate the 3-dimensional position of the scaphoid relative to the radius. To evaluate RSJ congruency, the inferred contact area between the scaphoid proximal pole and the distal radius was calculated from 3-dimensional bone models. RESULTS: The scaphoid position was not significantly different from normal wrists in stage IIIa Kienböck disease. Stage IIIb Kienböck disease was meaningfully associated with a flexed scaphoid and proximal translation of the centroid, but not dorsal translation of the scaphoid proximal pole, where RSJ congruity was preserved. With SLD, the scaphoid flexed to the same extent as that in stage IIIb Kienböck disease, and the proximal pole translated dorsally together with the capitate, producing RSJ incongruity. CONCLUSIONS: The patterns of carpal collapse differed between stage IIIb Kienböck disease and SLD in terms of RSJ congruity. Our study showed that stage IIIb Kienböck disease did not involve dorsal subluxation of the scaphoid proximal pole and that RSJ congruity was retained, unlike SLD. CLINICAL RELEVANCE: Our results suggest that carpal collapse in Kienböck disease is not associated with RSJ incongruity, which may explain why there are asymptomatic patients with Kienböck disease and carpal collapse.
PURPOSE: To examine 3-dimensional carpal alignment and radioscaphoid joint (RSJ) congruity among normal wrists and those with Lichtman stage III Kienböck disease or scapholunate dislocation (SLD). METHODS: We conducted 3-dimensional analysis based on computed tomographic data to compare 10 wrists of stage III Kienböck disease (5 IIIa and 5 IIIb) with 5 normal wrists and 3 wrists with SLD. A markerless bone registration technique was used to investigate the 3-dimensional position of the scaphoid relative to the radius. To evaluate RSJ congruency, the inferred contact area between the scaphoid proximal pole and the distal radius was calculated from 3-dimensional bone models. RESULTS: The scaphoid position was not significantly different from normal wrists in stage IIIa Kienböck disease. Stage IIIb Kienböck disease was meaningfully associated with a flexed scaphoid and proximal translation of the centroid, but not dorsal translation of the scaphoid proximal pole, where RSJ congruity was preserved. With SLD, the scaphoid flexed to the same extent as that in stage IIIb Kienböck disease, and the proximal pole translated dorsally together with the capitate, producing RSJ incongruity. CONCLUSIONS: The patterns of carpal collapse differed between stage IIIb Kienböck disease and SLD in terms of RSJ congruity. Our study showed that stage IIIb Kienböck disease did not involve dorsal subluxation of the scaphoid proximal pole and that RSJ congruity was retained, unlike SLD. CLINICAL RELEVANCE: Our results suggest that carpal collapse in Kienböck disease is not associated with RSJ incongruity, which may explain why there are asymptomatic patients with Kienböck disease and carpal collapse.