Proximity of the Triangular Fibrocartilage Complex to Key Surrounding Structures and Safety Assessment of an Arthroscopic Repair Technique: A Cadaveric Study

Abstract

To quantify the distance of the dorsal ulnar sensory branch, floor of the extensor carpi ulnaris (ECU) subsheath, and ulnar neurovascular bundles from the triangular fibrocartilage complex (TFCC), and secondarily to assess the safety of an all-inside arthroscopic repair of the TFCC with a commonly used meniscal repair device with respect to the aforementioned structures. A custom K-wire with 1-mm gradation was used to determine the distance of at-risk structures from the periphery of the TFCC in 13 above-elbow human cadaver specimens. An all-inside repair of the TFCC at the location of a Palmer 1B tear was then performed using a commonly employed meniscal repair device. The distance from the deployed devices to the structure in closest proximity was then measured using digital calipers. The mean distance from the deployed device to the nearest structure of concern for iatrogenic injury was 9.4mm (range, 5-15mm). The closest structure to iatrogenic injury was usually, but not always, the dorsal ulnar sensory nerve in 9 of 13 wrists (69.2%) at 9.3mm (range, 5-15mm); on 3 occasions it was instead the ulnar nerve (23.1%) at 9.5mm (range, 9-10mm), and on 1 occasion 6mm from the flexor digitorum profundus to the little finger (7.7%). Forearm rotation had no significant effect on measured distances (ulnar nerve: P= .98; dorsal sensory: P= .89; ECU: P= .90). The largest influence of forearm rotation was a 0.4-mm difference between pronation and supination with respect to the distance of the TFCC periphery on the ECU subsheath. An all-inside arthroscopic TFCC repair using a commonly used meniscal repair device appears safe with respect to nearby neurovascular structures and tendons under typical arthroscopic conditions. An all-inside arthroscopic TFCC repair using a commonly employed meniscal repair device appears safe in terms of proximity to important structures although further clinical investigation is warranted.