Weight-bearing test of traumatic triangular fibrocartilage complex lesion with unstable radioulnar joint

Abstract

Background: Ulnar-sided wrist pain might be caused by a lesion of the triangular fibrocartilage complex (TFCC). Patients with TFCC lesion may show an instability of the distal radioulnar joint (DRUJ). Before arthroscopic assessment, conservative therapy using a brace or splint may result in alleviation of symptoms. The results of our previous study showed that patients with a traumatic TFCC lesion and instability of the DRUJ had the smallest weight-bearing capacity and had the largest increase in application of the wrist brace (WristWidget).

Purpose: In this prospective study, we wanted to test if the weight-bearing capacity with and without the wrist brace can be used as a diagnostic tool to differentiate between patients with traumatic TFCC lesion and instability of the DRUJ. We tested if patients with traumatic TFCC lesion and instability of the DRUJ (1) have a lower weight-bearing capacity and (2) show a higher increase of weight-bearing capacity after application of a wrist brace compared to all other types of injury.

Study design: This was a prospective cohort study.

Methods: Forty-eight patients presented to an outpatient clinic with suspected TFCC lesion. We measured the dynamic weight-bearing capacity of both hands with and without the wrist brace (WristWidget) by letting the patients lean on an analog scale with extended arm and wrist. The stability of the DRUJ was assessed by clinical examination by a hand surgeon preoperatively and intraoperatively. Forty-five patients received an arthroscopy and were included in the analysis. During arthroscopy, the surgeon determined if there was a traumatic TFCC lesion and DRUJ instability. Patients with a traumatic lesion of the TFCC and DRUJ instability were compared to all other cases. We used the t-test for normally distributed values, Mann-Whitney U test for nonnormally distributed values, and the Chi-square test for categorical variables, respectively Fisher's exact if the expected cell count was less than five.

Results: Patients with a traumatic TFCC lesion and DRUJ instability had a higher weight-bearing capacity (22.8 kg) than all other cases (13.8 kg; p < 0.01). This is in contrast to our previous study, in which patients with a traumatic lesion of the TFCC had the tendency to show lower values of weight-bearing capacity than those with a degenerative lesion. While the wrist brace was worn, the relative gain was not significantly lower in patients with traumatic TFCC lesions and DRUJ instability compared to all other cases (21% vs 54%, p = 0.16). All included cases showed the same absolute increase of about 4 kg in weight-bearing capacity with the wrist brace (p = 0.93) CONCLUSIONS: The weight-bearing test cannot be used to identify patients with traumatic TFCC lesion and DRUJ instability among those with suspected TFCC lesion. The results of our previous study could be confirmed that the weight-bearing capacity on the injured side was higher with brace than without.

Keywords: Brace; Distal radioulnar joint instability; TFCC; Weight-bearing; Wrist; WristWidget.