Relationship between the ulnar styloid fracture and druj instability

48

THE JOUIZNAI..

OF HAND

SURGERY

VOL. 2813 SUPPLEMENT

I

SESSION 11: FOREARM AND WRIST 3 85.

THE SHAPE OF THE TRIANGULAH FIBROCARTILAGE

87.

RELATIONSHIP BETWEEN THE ULNAR STYLOID

DURING ROTATION

FRACTURE AND DRUJ INSTABILITY

Toshiyasu

Toshiyasu

Nakamura, Akio Makita, Osamu Watanabe.

Department qf Orthopaedic Surgery, School of Medicine, Keio University, 35 Shinanomachi, Shunjuku-ku, 160 Tokyo, Jupan Changes in shape of the triangular fibrocartilage (TFC) during rotation were studied in the disarticuIated and articulated wrists. Fourteen fresh cadavers were used. Small metal markers were set on the TFC. Changes in shape of the TFC were measured through photographs of disarticulated wrists and radiographs of the ‘articulated specimens in three dimensions. The Influence of ulnar lengthening on distortion of the disc was also examined using an external fixator. In the disarticulated wrists, there was a slight distortion in the TFC in the ulnar neutral variance specimens. The more distortion was noted in the more positive ulnar variance specimens or ulnar lengthening specimens. However, in the articulated wrist, the TFC demonstrated little change in shape during rotation in either the neutral, ulnar positive variance or ulnar lengthening specimens. These findings suggest that increased ulnar variance would produce distortion in the disc but the carpus helps to maintain the shape of the TFC during pronation-supination, due to the force transmission between the ulnar carpus and the ulnar head through the TFC.

86.

EVALUATION OF THE 42 TFCC TEARS BY ARTHROSCOPY

Nakamura’,

Owen J. May’,

Clayton

A. Peimer’.

‘Departmentqf Orthopaedic Surgery, School of Medicine, Keio Univeristy, 35 Shinanomuchi, Shunjuku-ku, 160 Tokyo, Japan; 2Hund Center of Western New York, Stute University qf New York, B@alo. NZ USA \+‘e examined changes in DRUJ stiffness after simulating four types of ulnar styloid fracture. Ten fresh-frozen cadavers were used. After the tip, middle, base horizontal, and base oblique type of the ulnar styloid fracture was made sequentially, changes in dorsopalmar DRUJ stiffness were measured in intact wrist, each fracture sequence at 60 degree pronation, neutral and GO degree supination. Additional cutting of the radioulnar ligament was also simulated with base horizontal fracture. Loss of DRUJ stiffness was calculated in each simulated fracture, and RUL sectioning. The tip and middle portion of the styloid fractures did not demonstrate significant loss of stiffness compared with the intact. The base horizontal fracture demonstrates lo-22% loss of dorsopalmar stiffness of the DRUJ. The base oblique fracture indicates significant instability of the DRUJ (30.70% loss). Additional section of the radioulnar ligament induced significant (25-46%) loss of stiffness of the DRUJ with the intact. From these findings, large styloid fractures including the RUL origin may destabilize the DRUJ. Tip or middle ulnar styloid fracture did not indicate DRUJ instability, because it does not include TFCC origin.

AND MRl

F. Garcia de Lucas, J.M. Abad Morenilla, J.R. Almoguera, G. L6pez, R. Carrillo. Hospital FREMAR Majadahonda, Madrid, Spain Introduction:

Disorders of the TFCC are responsible for many of the ulnar-sided wrist symptoms that clinically affect patients’ function. Recognition and treatment of these injuries to the TFCC relieve pain about the ulnar aspect of the wrist, with a good prognosis for functional return. Aims: Evaluation of MRI in the tears of the TFCC. Material and methods: Wrist arthroscopy were carried out in forty-two patients with symptomatic wrist and preoperative MRI studies of the TFCC tears. All arthroscopies were carried out by two of the surgeons hand (G de L and A M). Results: Traumatic tears were noted in 9 patients and degenerative tears in 24 patients. Nine patients noted normal TFCC. MRI studies showed: true negative in 5 wrist, false positive in 4 wrist and false negative in 5 wrist. The sensitivity was 85%, the specificity was 56% and accuracy was 79%. Discussion and Cunclusions: The lo&ion by MRI of the TFCC tears is more accurate on the radial side than on the ulnar side. MRI does not differentiate between traumatic and degenerative tears. Arthroscopy is more accurate diagnostic technique than MRI studies and besides it is a therapeutic technique for management of the TFCC tears.

88.

PREVALENCE OF SUBLUXATION OF DISTAL

RADIOULNAR JOINT OR SCAPHOLUNATE DISSOCIATION AFTER DISTAL RADIUS FRACTURE

Kim Byung Sung, Won-Sik Choy. Eulji Meciical University Hospital, Duejeon, South Korea Purpose: To analyze the distal radioulnar

subluxation and scapholunate dissociation after distal radius fracture Materials and methods: Forty six cases were analyzed clinically and radiographically, and were followed up for at least one year. Twenty four cases were treated by closed reduction and percutaneous k-wire fixation, twelve cases by closed reduction, k-wire and external lixator application, ten cases by open reduction and plate fixation. For functional evaluation, Gartland score, ROM, and grip power were analyzed. For radiological evaluation, scapholunate gap and angle, radiolunate angle, ulnar variance and distal radioulnar joint subluxation were analyzed. Results: Distal radius fractures with fracture line involving DRUJ have a significant decrease of supination and grip power. After 1 year 6 of the 46 patients have DRUJ subluxation. The wrists with DRUJ subluxation have more positive ulnar variance than the wrists without DRUJ subluxation. The wrists with DRUJ subluxation show 2 cases of DISI and lcase of VISI pattern. The wrists with Initial fracture line involving DRUJ, ulnar styloid process involvement or initial dorsal angulation (>20”) did not significantly