Abstract
The pattern of injury to the carpal ligaments following wrist trauma is unclear. Different imaging techniques often prove inconclusive rendering the diagnosis difficult and hence the treatment controversial. This study aimed to observe and evaluate the differences in scapholunate kinematics before and after sectioning the scapholunate interosseous ligament (SLIL) and radioscaphocapitate ligament (RSC).
Twenty two embalmed cadaveric wrists were used. There were four males and seven females with an average age of 84 years. Their medical records confirmed the absence of previous history of wrist diseases or injuries. The extensor and flexors tendons of the wrist were removed leaving the capsule intact. Two drill bits (1.5 mm) were used to make a hole each in scaphoid and lunate, one centimeter apart. The drill bits were left in the bones to act as metal wires for calibration. Each wrist was moved through a set of motions and each movement was performed thrice; first one with the ligaments intact, second with SLIL sectioned and the last one with RSC excised. Digital photographs were taken and angles measured with MB Ruler software. Analysis of variance was done using SPSS 12.
There was no angle between the metal pointers when the ligaments were intact. There was movement and change in angle detected when SLIL and RSC were sectioned. The sectioning of the SLIL lead to a significant increase in the angle between the pointers in all the movements recorded (p value < 0.001). Subsequent sectioning of the RSC further increased this angle but this increase was much smaller compared to that after sectioning SLIL. On completion of the measurements the wrist capsule was opened to reveal that both the ligaments had been successfully sectioned and there were no degenerative changes in the bones or ligaments in any wrist.
This first cadaveric evaluation of alterations in scapholunate motion with sectioning of SLIL and RSC revealed that SLIL has a significant influence on the scapholunate kinematics, where as sectioning of the RSC has little additional effect. This in-vivo finding might have implications of importance of preserving SLIL during wrist surgeries and its role in management of carpal instabilities.
Correspondence should be addressed to Mr Carlos Wigderowitz, Senior Lecturer, University Department of Orthopaedic and Trauma Surgery, Ninewells Hospital and Medical School, Dundee DD1 9SY.
