DOS 2017

132

· DOS Abstracts

STATIC AND DYNAMIC RADIOSTEREOMETRIC ANALYSIS

FOR EVALUATION OF INSTABILITY IN THE DISTAL RA-

DIOULNAR JOINT BEFORE AND AFTER TFCC LESIONS

Janni Kjærgaard Thillemann, Sepp De Raedt, Peter Bo Jørgensen, Bart Kaptein, Lone

Rømer, Torben Bæk Hansen , Maiken Stilling

Department of Orthopaedics, University Clinic of Hand, Hip and Knee Surgery, Hos-

pital Unit West, DK ; Nordic Roentgen Technique, Aarhus, DK, ; Department of Clini-

cal Medicine, Aarhus University, DK; Leiden University Medical Center, Leiden, NL,

; Department of Radiology, Aarhus University Hospital, DK; Department of Ortho-

paedics, University Clinic of Hand, Hip and Knee Surgery, Hospital Unit West, DK ;

Department of Clinical Medicine, Aarhus University, DK

Background:

Injury of the Triangular Fibrocartilage Complex(TFCC) can lead to dis-

tal radioulnar joint(DRUJ) instability. Wrist arthroscopy is the gold standard diagnos-

ing TFCC injuries since current imaging examinations are insufficient.

Purpose / Aim of Study:

To evaluate DRUJ kinematics without and with TFCC le-

sions using radiostereometry(RSA).

Materials and Methods:

DRUJ stability of 10 human donor arms were evaluated

with static RSA during Piano Key test and with dynamic RSA(dRSA) during radial-

ulnar wrist motion. Recordings were obtained before and after cutting first the distal

component(dc-TFCC) at the ulnar styloid, and next the proximal component(pc-

TFCC) from the ulna fovea. Lesions were checked with wrist arthroscopy. CT based

bone models were used for kinematic analysis with non-commercial AutoRSA soft-

ware. Ulnar variance, DRUJ gapping and DRUJ translation was calculated. Anatomical

coordinate system was used.

Findings / Results:

Static RSA: The Piano Key test had a mean 1.80mm(CI95

0.64-2.95) DRUJ translation with intact TFCC, increasing to mean 2.66mm(CI95

1.80- 3.52) with dc-TFCC/pc-TFCC lesion(p=0.02). dRSA: DRUJ gapping and ulnar

variance was reduced in ulnar wrist deviation compared to radial wrist deviation with

both intact and cut dc-TFCC and pc-TFCC(p<0.01). The change in gapping and ul-

nar variance was similar before and after lesion of the TFCC(p>0.07). DRUJ transla-

tion was mean 0.83mm(CI95 0.57- 1.09) with intact TFCC. After dc-TFCC lesion

DRUJ translation was similar(p=0.13), while a combined dc-TFCC/pc-TFCC lesion

increased(p=0.02) DRUJ translation to mean 1.36mm(CI95 0.95-1.77).

Conclusions:

Successive lesion of the dc-TFCC and pc-TFCC resulted in increasing

DRUJ instability. dRSA is a novel non-invasive, low-dose radiological method. dRSA

options in vivo quantification of DRUJ stability in patients during symptom provoking

wrist motions.

No conflicts of interest reported

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