Introduction Frequently occur with distal radius fractures but must be considered independently common cause of pain and limited ROM after distal radius fractures often underappreciated and ignored Etiology Associated conditions ulnar styloid and distal ulna fractures TFCC tears ulnar impaction syndrome Essex-Lopresti injuries Galeazzi fractures Anatomy DRUJ arthrology articulation occurs between the ulnar head and sigmoid notch (a shallow concavity found along ulnar border of distal radius) most stable in supination primary stabilizers volar and dorsal radioulnar ligaments TFCC TFCC attaches to the fovea at the base of the ulnar styloid components include central articular disc meniscal homologue volar and dorsal radioulnar ligaments ulnolunate and ulnotriquetral ligament origins floor of the ECU tendon sheath biomechanics joint motion includes both rotation and translation Presentation Symptoms pain and instability with acute DRUJ dislocation associated with open distal radius fractures dorsal wrist pain and limited pronosupination with post-traumatic arthritis Physical exam post-traumatic arthritis snapping and crepitus proximal rotation of the forearm with compression of the ulna against the radius elicits pain decreased grip strength Imaging Radiographs AP shows widening of the DRUJ lateral shows dorsal displacement instability of the DRUJ is present when the ulnar head is subluxed from the sigmoid notch by its full width with the arm in neutral rotation Dynamic CT useful in the diagnosis of subtle chronic DRUJ instability sequential CT scans are performed with the forearm in neutral and full supination and pronation >50% translation compared to the contralateral side is abnormal MRI useful in the identification of TFCC injuries Treatment Nonoperative closed reduction, immobilization indications DRUJ instability resulting from purely ligamentous injury techniques closed reduction and immobilization in a position of stability for 4 weeks dorsal instability is stable with the forearm in supination volar instability is stable in pronation outcomes interposition of ECU may impede closed reduction Operative DRUJ pinning, radioulnar ligament repair indications highly unstable DRUJ techniques pinning across joint with 0.062-inch K-wires Ulnar Styloid Fractures Reflects high degree of initial fracture displacement Fractures through base often associated with TFCC rupture and instability In the absence of instability, ulnar styloid nonunions are not associated with worse outcomes Treatment nonoperative cast immobilization indications nondisplaced fractures proximal to the ulnar styloid operative ORIF, symptomatic fragment excision indications displaced fractures through the base with associated instability sigmoid notch fractures Galeazzi fracture patterns TFCC avulsions in the face of an unstable DRUJ techniques preserve ulnar attachments of TFCC with fragment excision TFCC Tears Etiology Mechanism of injury wrist extension, forearm pronation in pronation, volar ligaments prevent dorsal subluxation in supination, dorsal ligaments prevent volar subluxation Classification type I - traumatic type II - degenerative (ulnocarpal impaction) IIA - TFCC thinning IIB - IIA + lunate and/or ulnar chondromalacia IIC - IIB + TFCC perforation IID - IIC + LT ligament disruption IIE - IID + ulnocarpal and DRUJ arthritis Treatment nonoperative immobilization, NSAIDS indications all acute traumatic TFCC tears operative arthroscopic vs. open debridement and/or repair indications failure of nonoperative management persistent symptoms techniques type I injuries arthroscopic vs. open debridement and/or repair type II injuries TFCC pathology treated with arthroscopic or open debridement ulnocarpal impaction treated with ulnar shortening osteotomy (in the absence of DRUJ arthrosis) or wafer resection of the ulnar head Ulnar Impaction Syndrome Radial shortening leads to positive ulnar variance and altered mechanics Sequelae includes lunate chondromalacia degenerative TFCC tears Operative treatment TFCC debridement radial osteotomy ulnar shortening distal ulnar resection (Wafer procedure) preserve ulnar attachment of TFCC Essex-Lopresti Injuries Radial head fracture with an interosseous membrane injury extending to DRUJ unstable relationship between ulna and radius leads to proximal migration of the radius results in secondary DRUJ pathology and ulnocarpal abutment Treatment treat bony pathology (radial head or shaft) pin DRUJ for 6 weeks in neutral to facilitate ligamentous healing if pinning fails (or the initial injury is missed) radial head replacement may be required Galeazzi Fractures Distal one-third fracture of the radius and a DRUJ injury ECU entrapment may cause DRUJ to be irreducible Treatment nonoperative splint in supination indications rarely indicated for stable injuries operative radial ORIF and DRUJ pinning indications often required to achieve a stable reduction Complications DRUJ arthrosis treatment resection arthroplasty (resect distal ulna) matched resection vs. Darrach Darrach procedure reserved for low-demand, elderly patients an unstable, painful proximal ulna stump may result hemiresection or interposition arthroplasty ulnar insertion of TFCC is preserved radioulnar impingement is prevented by soft tissue interposition Sauve-Kapandji procedure DRUJ fusion with creation of a proximal ulnar neck pseudoarthrosis ulnar head prosthetic replacement creation of a one-bone forearm ultimate salvage procedure that eliminates forearm rotation Prognosis Primary method to prevent disability related to DRUJ injuries is anatomic reduction of the distal radius which often results in an anatomically-reduced DRUJ