Arthroscopic Inside-Out Transosseous or Over-the-Top Foveal Triangular Fibrocartilage Complex (TFCC) Repairs with Distal Radioulnar Joint (DRUJ) Instability: A Biomechanical Study

The TFCC is the primary stabilizer of the DRUJ. Injury to the deep part, or a foveal injury, can cause ulnar-sided wrist pain and DRUJ instability.The aim of this study was to assess DRUJ translation and stability after TFCC foveal repair using an arthroscopic Over-the-Top technique.

After obtaining institutional approval, eight fresh frozen cadavers were used in this study. The stability of the DRUJ with an intact foveal insertion followed by its repair via the Over-the-Top technique was performed, examining the affects of different suture configurations. DRUJ translation was assessed in three positions: neutral, pronation at 60 degrees, and supination at 60 degrees.

Distal radioulnar joint (DRUJ) instability significantly increased between the intact and injured conditions [mean translation difference: 6.39 mm in neutral (P = 0.008), 5.18 mm in pronation (P = 0.049), and 6.40 mm in supination (P = 0.012)]. Stability improved with the 1-suture group (42.3%, 50.3%, 54.7%), the 2-suture group (85.3%, 81.4%, 82.8%), and the 3-suture group (98.4%, 102.6%, 95.6%) compared to baseline (all P < 0.05). However, no significant improvement was found when comparing the 2-suture group to the 3-suture group (13.1%, 21.2%, 12.9%; all P > 0.05) in neutral, pronation, and supination, respectively.

Over the Top TFCC foveal repair can enhance the stability of the DRUJ. A single suture repair provides about half the stability compared to the injured state, while the two-suture group may provide similar stability comparable to the three-suture group.

Keywords: TFCC injury, DRUJ instability, Foveal injury, Arthroscopic foveal repair,