Kleinman, J Hand Surg Am 2007 - Stability of the Distal Radioulna Joint: Biomechanics, Pathophysiology, Physical Diagnosis, and Restoration of Function What We Have Learned in 25 Years - Article Summary

Stability of the Distal Radioulna Joint: Biomechanics, Pathophysiology, Physical Diagnosis, and Restoration of Function What We Have Learned in 25 Years

Kleinman·J Hand Surg Am·2007·311 citations·Review article

Kleinman's 2007 Clinical Perspective synthesizes 25 years of research on DRUJ biomechanics, anatomy, physical diagnosis, and surgical reconstruction — focusing on what structures actually stabilize the DRUJ during loaded forearm rotation and how to identify and repair them when they fail.

Key Findings

The Ligamentum subcruentum (deep TFC fibers inserting into the ulnar fovea) is the principal DRUJ stabilizer — its obtuse angle of attack from medial radius to fovea gives it far greater mechanical advantage than the superficial radioulnar fibers inserting onto the styloid
In neutral wrist position, 84% of load passes to the radius and only 16% through the TFC disc; ulnar deviation shifts the axis medially onto the disc and ulnar pole
At end-arc rotation, <10% of the sigmoid notch remains in contact with the ulnar seat, rendering superficial TFC fibers mechanically irrelevant — only the Ligamentum subcruentum prevents subluxation
A displaced basilar ulnar styloid fracture means the Ligamentum subcruentum is avulsed from the fovea by the exact same displacement distance — DRUJ instability is guaranteed without anatomic restoration
Isolated Ligamentum subcruentum avulsion can exist with a normal ulnocarpal arthroscopy and intact superficial TFC (10 such cases confirmed at Indiana Hand Center); diagnosis requires provocative stress testing and open repair

Supplemental

Stability of the Distal Radioulna Joint: Biomechanics, Pathophysiology, Physical Diagnosis, and Restoration of Function What We Have Learned in 25 Years.