- Email: [email protected]
The DRUJ Stabilizing Mechanism by Distal Interosseous Membrane in Ulnar Shortening Procedure: A Biomechanical Study
PAPER 12 ∙
Friday, October 8, 2010 8:49-8:56 AM Paper Session 1: Elbow and Ulnar Wrist
The DRUJ Stabilizing Mechanism by Distal Interosseous Membrane in Ulnar Shortening Procedure: A Biomechanical Study Not a clinical study v Sayuri Arimitsu, MD
SUMMARY POINTS ∙ We found a DRUJ stabilizing effect by increasing tension of the dIOM in ulnar shortening which has not been previously discussed. ∙ Ulnar shortening with osteotomy carried out proximal to the attachment of the dIOM had a favorable effect on DRUJ stability when compared with distal, especially in conditions with a DOB. REFERENCES 1. Noda K, et al. Interosseous membrane of the forearm: an anatomical study of ligament attachment locations. J Hand Surg Am, 2009. 34(3):415-22. 2. Moritomo H, et al. Interosseous membrane of the forearm: length change of ligaments during forearm rotation. J Hand Surg Am, 2009. 34(4):685-91. 3. Nishiwaki M, et al. Ulnar shortening effect on distal radioulnar joint stability: a biomechanical study. J Hand Surg Am, 2005. 30(4):719-26.
Hisao Moritomo, MD Takashi Kitamura, MD Kristin D. Zhao, MA Kai-Nan An, PhD Marco Rizzo, MD HYPOTHESIS The importance of the stabilizing effect of the distal interosseous membrane (dIOM) on the distal radioulnar joint (DRUJ) has been described, especially in patients with a distal oblique bundle (DOB) which was an obvious thick fiber within the dIOM. We hypothesized that the increased tension of the dIOM with an osteotomy carried out proximal to the attachment of the dIOM might improve DRUJ stability. METHODS 10 fresh frozen cadavers were used for this study. The DRUJ stability following ulnar shortening and the stiffness of ulnar shortening were evaluated between an osteotomy carried out proximal (proximal shortening) and distal (distal shortening) to the ulnar attachment of dIOM and between conditions of the dIOM with and without a DOB. The DRUJ laxity was evaluated as the volar and dorsal displacements of radius relative to the fixed ulna with 20 N tensile force applied. Testing was performed before the shortening and under the controlled shortening using custom made plate with a sliding hole at intervals of 1 mm up to 4 mm. The stiffness of the ulna due to ulnar shortening was quantified as the slope of the load-displacement curve obtained by displacing the distal ulnar segment proximally using a vertical uniaxial load frame. RESULTS In the proximal shortening a significantly greater DRUJ stability was obtained with only 1mm of shortening compared with the control, while the distal shortening showed the significant improvement in the DRUJ stability only after 4 mm or more of shortening (Figure 1 (a), (b)). A significantly greater DRUJ stabilizing effect was achieved with proximal shortening than distal shortening. We found a DOB in 4 of 10 specimens (40%). A significantly greater DRUJ stability was obtained compared to controls with a smaller amount of shortening in the group with DOB than without DOB (Figure 1(c), (d)), and the DRUJ stabilizing effect was significantly greater in the groups with a DOB than without a DOB. The stiffness in ulnar shortening was significantly greater in the proximal shortening than distal. The stiffness in proximal shortening was insignificantly greater in the group with DOB than without DOB. v Speaker has nothing of financial value to disclose
PAPER 13 ∙
Friday, October 8, 2010 8:00-8:07 AM Paper Session 2: Wrist
False Positive MRI’s for Scaphoid Fracture in Healthy Volunteers Not a clinical study v Andele de Zwart, Jr.
Frank J. P. Beeres, MD, PhD Sven Meylaerts, MD, PhD Daan Otis, Jr. MDavid C. Ring, MD, PhD Steven Rhemrev, MD HYPOTHESIS MRI is not 100% specific for diagnosing an occult scaphoid fracture.
11
Friday, October 8, 2010 8:49-8:56 AM Paper Session 1: Elbow and Ulnar Wrist
The DRUJ Stabilizing Mechanism by Distal Interosseous Membrane in Ulnar Shortening Procedure: A Biomechanical Study Not a clinical study v Sayuri Arimitsu, MD
SUMMARY POINTS ∙ We found a DRUJ stabilizing effect by increasing tension of the dIOM in ulnar shortening which has not been previously discussed. ∙ Ulnar shortening with osteotomy carried out proximal to the attachment of the dIOM had a favorable effect on DRUJ stability when compared with distal, especially in conditions with a DOB. REFERENCES 1. Noda K, et al. Interosseous membrane of the forearm: an anatomical study of ligament attachment locations. J Hand Surg Am, 2009. 34(3):415-22. 2. Moritomo H, et al. Interosseous membrane of the forearm: length change of ligaments during forearm rotation. J Hand Surg Am, 2009. 34(4):685-91. 3. Nishiwaki M, et al. Ulnar shortening effect on distal radioulnar joint stability: a biomechanical study. J Hand Surg Am, 2005. 30(4):719-26.
Hisao Moritomo, MD Takashi Kitamura, MD Kristin D. Zhao, MA Kai-Nan An, PhD Marco Rizzo, MD HYPOTHESIS The importance of the stabilizing effect of the distal interosseous membrane (dIOM) on the distal radioulnar joint (DRUJ) has been described, especially in patients with a distal oblique bundle (DOB) which was an obvious thick fiber within the dIOM. We hypothesized that the increased tension of the dIOM with an osteotomy carried out proximal to the attachment of the dIOM might improve DRUJ stability. METHODS 10 fresh frozen cadavers were used for this study. The DRUJ stability following ulnar shortening and the stiffness of ulnar shortening were evaluated between an osteotomy carried out proximal (proximal shortening) and distal (distal shortening) to the ulnar attachment of dIOM and between conditions of the dIOM with and without a DOB. The DRUJ laxity was evaluated as the volar and dorsal displacements of radius relative to the fixed ulna with 20 N tensile force applied. Testing was performed before the shortening and under the controlled shortening using custom made plate with a sliding hole at intervals of 1 mm up to 4 mm. The stiffness of the ulna due to ulnar shortening was quantified as the slope of the load-displacement curve obtained by displacing the distal ulnar segment proximally using a vertical uniaxial load frame. RESULTS In the proximal shortening a significantly greater DRUJ stability was obtained with only 1mm of shortening compared with the control, while the distal shortening showed the significant improvement in the DRUJ stability only after 4 mm or more of shortening (Figure 1 (a), (b)). A significantly greater DRUJ stabilizing effect was achieved with proximal shortening than distal shortening. We found a DOB in 4 of 10 specimens (40%). A significantly greater DRUJ stability was obtained compared to controls with a smaller amount of shortening in the group with DOB than without DOB (Figure 1(c), (d)), and the DRUJ stabilizing effect was significantly greater in the groups with a DOB than without a DOB. The stiffness in ulnar shortening was significantly greater in the proximal shortening than distal. The stiffness in proximal shortening was insignificantly greater in the group with DOB than without DOB. v Speaker has nothing of financial value to disclose
PAPER 13 ∙
Friday, October 8, 2010 8:00-8:07 AM Paper Session 2: Wrist
False Positive MRI’s for Scaphoid Fracture in Healthy Volunteers Not a clinical study v Andele de Zwart, Jr.
Frank J. P. Beeres, MD, PhD Sven Meylaerts, MD, PhD Daan Otis, Jr. MDavid C. Ring, MD, PhD Steven Rhemrev, MD HYPOTHESIS MRI is not 100% specific for diagnosing an occult scaphoid fracture.
11