Distal radius fracture with concomitant ulnar styloid fracture: does distal radioulnar joint stability depend on the location of the ulnar styloid fracture?

INTRODUCTION

Studies are conflicting regarding the relationship between ulnar styloid fracture (USF) location and distal radioulnar joint (DRUJ) instability in patients with distal radius fracture (DRF) and concomitant USF. The objective of this study was to determine the association of USF location with TFCC foveal tear and factors associated with DRUJ instability in patients with both DRF and USF.

MATERIALS AND METHODS

Fifty-four patients with both DRF and USF who had wrist MRI examination before surgery were analyzed. USF location (tip or base) and TFCC foveal insertion status (intact, partial tear, or complete tear or avulsion with fractured fragment) were evaluated. DRUJ stability was assessed intra-operatively after fixation of the radius. Factors potentially associated with DRUJ instability, such as age, gender, USF location, USF fragment gap, radioulnar distance, radial shortening, and TFCC foveal tear, were analyzed.

RESULTS

Among 54 patients, 37 (69%) and 17 (31%) had USF at the base and the tip, respectively. In patients with base fractures, TFCC foveal insertion was found to be disrupted in 89% (33/37) patients (complete tear in 11 and partial tear in 22) but intact in 11% (4/37). On the contrary, in patients with tip fractures, the insertion was found to be disrupted in 88% (15/17) patients (complete tear in 2 and partial tear in 13) but intact in 12% (2/17). After fixation of the radius, total 52% (28/54) patients showed DRUJ instability. Especially, DRUJ instability was found in 57% (21/37) of ulna styloid process base fracture patients and 41% (7/17) of ulna styloid process tip fracture patients. In univariate analysis, complete tear of TFCC foveal insertion and wider USF fragment distance were associated with DRUJ instability.

CONCLUSIONS

Tears of TFCC foveal insertion are common in patients with DRF and concomitant ulnar styloid base fractures. Based on the findings of this study, tear of TFCC foveal insertion seems to be also common in patients with DRF and concomitant ulnar styloid tip fractures. And also, DRUJ instability seems to be associated with a TFCC foveal tear independent of USF location.

Morphology of the Ulnar Insertion of the Triangular Fibrocartilage Complex and Related Osseous Landmarks

PURPOSE

In triangular fibrocartilage complex (TFCC) injuries, a foveal tear of the radioulnar ligament often requires surgery. Previous studies have suggested that surgeons should attach the TFCC to the center of the fovea. The TFCC and its insertion points are small structures, and few studies have reported details of the foveal insertion. This study aimed to clarify the morphology of the ulnar insertion of the TFCC and related osseous landmarks with 3-dimensional imaging.

METHODS

This study used 26 formalin-fixed cadavers. At the ulna, the TFCC was inserted from the fovea to the middle part of the ulnar styloid. After gross observation of the TFCC, the ulnar insertion was outlined using a 1.0-mm drill. We then created 3-dimensional images of the ulna using computed tomography and marked (with software) an outline of the foveal insertion of the TFCC. We measured the area and the long and short diameters of the TFCC insertion.

RESULTS

The area of the TFCC insertion was 34 mm² and positively correlated with the height of the ulnar styloid and the area of the ulnar head. The TFCC's highest point was 58% of the ulnar styloid height. The center of the TFCC insertion was 1.3 mm ulnar and 0.6 mm dorsal from the lowest point of the ulnar surface.

CONCLUSIONS

The center of the TFCC insertion was slightly ulnar of the lowest point of the ulnar surface. This study revealed the center, the area, and the osseous relation of the ulnar insertion of the TFCC.

CLINICAL RELEVANCE

When surgeons repair a TFCC foveal tear, they can find the anatomical center of the ulnar insertion efficiently and easily based on its osseous relationship.

Arthroscopic Trans-osseous Suture of Peripheral Triangular Fibrocartilage Complex Tear

The importance of foveal repair of the triangular fibrocartilage complex (TFCC) on stability of the distal radioulnar joint (DRUJ) has been emphasized with increasing knowledge of the anatomy and biomechanics of the TFCC and DRUJ. Although both open and arthroscopic techniques have been described for improving DRUJ stability, there has been a marked evolution of arthroscopic TFCC repair technique with successful clinical outcome. Recently, an arthroscopic trans-osseous technique has been described to repair foveal tears of the TFCC. The advantage of the technique is that it allows for anatomical repair of both the superficial and deep layers. This article describes the details of this novel technique.

Arthroscopic one-tunnel transosseous foveal repair for triangular fibrocartilage complex (TFCC) peripheral tear

PURPOSE

Arthroscopic repair of a peripheral triangular fibrocartilage complex (TFCC) tear is a promising, minimally invasive surgical technique, especially in patients with symptomatic distal radioulnar joint (DRUJ) instability. The purpose of this study was to evaluate the clinical result of arthroscopic one-tunnel transosseous foveal repair for peripheral TFCC tears.

METHODS

Sixteen patients who underwent TFCC foveal repair were retrospectively evaluated. The mean follow-up period was 31.1 months. The torn TFCC of all patients was repaired with the arthroscopic one-tunnel transosseous foveal repair technique. Postoperative outcomes were evaluated using the visual analogue scale (VAS) for pain, wrist range of motion, grip strength, Mayo wrist score, Quick Disabilities of the Arm, Shoulder and Hand (Quick DASH) score, and postoperative complications.

RESULTS

On arthroscopic examination, all 16 patients showed Palmer 1B type peripheral TFCC tears with foveal disruption. Among them, 13 patients had a proximal component TFCC tear (Atzei class 3) and 3 patients had a complete TFCC tear (Atzei class 2). At the final follow-up, the mean range of the pronation-supination arc (P = 0.03) and grip strength (P = 0.001) was significantly increased. Twelve patients had normal stability of the DRUJ and six patients showed mild laxity compared with the contralateral side. The mean VAS for pain perception decreased from 3.7 to 0.8 (P = 0.001). The modified Mayo wrist (P = 0.001) and Quick DASH (P = 0.001) scores showed significant functional improvement. No surgery-related complications occurred.

CONCLUSIONS

The present study shows that arthroscopic one-tunnel transosseous repair is a good treatment strategy for TFCC foveal tears in terms of reliable pain relief, functional improvement, and re-establishment of DRUJ stability.