ROUNDS RESPONSE.
Rounds is your vehicle for sharing your orthopaedic skills and experience. Your response to Rounds will be published in a future issue of Body Cast. We invite you to suggest questions for this column. Please address all submissions to: The Editor, Body Cast, 18 Wynford Drive, Suite 715A, North York, Ontario, M3C 3S2.

This Issue's Rounds Question -
Please tell us:
What is Osteitis Pubis?

(responses to be published in next issue)

In the last issue of Body Cast, Rounds asked:
What is scapholunate dissociation? Why is it important?

The following responses were received:

From Ed Clancey and Neil Lockyer:
Scapholunate dissociation is the most common carpal instability associated with increased scaphoid flexion and pronation with associated lunate extension.
Several studies have shown that disruption of the scapholunate interosseous ligament changes carpal motion.

Often seen on radiographs in the AP plain as an abnormal gap between the scaphoid and lunate, "Terry Thomas" sign, normal (1 mm to 2 mm), abnormal 3mm.
This is important because the abnormal articulation causes an increased concentration of load, leading to the development of degenerative arthritis.

From John Yarnell:
Scapholunate dissociation is the most common carpal instability injury, aka the Terry Thomas sign. A gap of 1 mm to 2 mm is normal, 3 mm is abnormal. Instability of the scapholunate joint involves tears in the scapholunate interosseous and palmar radioscaphoid ligaments, creating a dorsal intercalated segment instability. This is important because if untreated it can lead to wrist instability and reduced grip strength, as well as degenerative arthritis.

From Brian Lavallee:
Scapholunate dissociation is the most common carpal instability. Scapholunate instability is associated with increased scaphoid flexion and pronation with associated lunate extension. The abnormal kinematics lead to a decrease in surface area contact at the radioscaphoid joint. This abnormal articulation causes an increased concentration of load, leading to the development of degenerative arthritis. Watson and coworkers described the typical pattern of wrist arthritis related to scapholunate instability, which has been termed scapholunate advanced collapse SLAC wrist. The goals of the surgical reconstructions for a scapholunate dissociation are to relieve the symptoms associated with the instability, maintain motion, and prevent the development of degenerative arthritis.

Responses were also received from: R. Aceron, L. Arseneau, R. Bartel, T. Bellon, F. Brooks, D. Brown, M.J. Buchner, L. Burk, J. Cannon, J. Carragher, M. Christenson, E. Christiansen, A. Crossman, V Dairon, D. Edwards, W. Fast, H. Fehr, M. Gillingham, R. Grenier. S. Groulz, E. Hayes, L. Head, S. Hutchinson, R. Ip Fung Chun, S. Jankowski, B. Letourneau, C.Longphee, L. Lough, L. MacDonald, G.Marshall, B Matheson, J. Mauhucci, J. McCulloch, J. Movasseli, E. Oborowsky, R. Pagay, R. Passmore, J.P. Piche, J. Pike, L. Pizzale, E. Place, P. Power, J. Punwassie, B. Rawlings, C. Rivers, V. Robichaud, K. Shaw, B. Sheppard, S. Shivpaul, V. Stockdale, A. Tarambikos, M. Walker, A. Wentzell, J. Wilson, H. Wong, N. Yao, T. Yorke, and M. Young