Summary Ulnocarpal Abutment Syndrome is a common source of ulnar sided wrist pain secondary to excessive impact stress between the ulna and the carpal bones (primarily lunate). Diagnosis is made with PA wrist radiographs showing positive ulnar variance and sclerosis of the lunate. Treatment includes a trial of rest and splinting for minimally symptomatic patients. Operative ulnar shortening procedures are indicated depending on severity of symptoms. Etiology Pathoanatomy in a wrist with +2 mm ulnar variance approximately 40% of the load goes to the ulna 60% to the radius in a normal neutral wrist approximately 20% of the load goes to the ulna 80% to the radius Associated conditions positive ulnar variance can be seen in the setting of: scapholunate dissociation TFCC tears lunotriquetral ligament tears radial shortening from previous Colles fracture Presentation Symptoms pain on dorsal side of DRUJ increased pain with ulnar deviation of wrist pain with axial loading ulna sided wrist pain Physical exam Ballottement test dorsal and palmar displacement of ulna with wrist in ulnar deviation positive test produces pain Nakamura's ulnar stress test ulnar deviation of pronated wrist while axially loading, flexing and extending the wrist positive test produces pain fovea test used to evaluate for TFCC tear or ulnotriquetral ligament tear performed by palpation of the ulnar wrist between the styloid and FCU tendon Imaging Radiographs recommended views AP radiograph with wrist in neutral supination/pronation and zero rotation required to evaluate ulnar variance pronated grip view increases radiographic impaction arthrography can show TFCC tear and lunotriquetral ligament tear findings ulna positive variance sclerosis of lunate and ulnar head MRI evaluate for TFCC tears which may be caused by ulnocarpal impingement and often influences treatment Differential Ulnar styloid impaction syndrome DRUJ instability or arthritis TFCC tear LT ligament tear pisotriquetral arthritis ECU tendonitis or instability Lunotriquetral coalition Treatment Nonoperative supportive measures indications may attempt supportive measures as first line of treatment Operative ulnar shortening osteotomy indications most cases of ulnar positive variance most cases of DRUJ incongruity Wafer procedure technique 2 to 4mm of cartilage and bone removed from under TFCC arthroscopically Darrach procedure (ulnar head resection) indications reserved for lower demand patients complications risk of proximal ulna stump instability Sauvé-Kapandji procedure indications good option for manual laborers technique creates a distal radioulnar fusion and a ulnar pseudoarthrosis proximal to the fusion site through which rotation can occur ulnar hemiresection arthroplasty indications usually requires an intact or reconstructed TFCC appropriate treatment option in the presence of post-traumatic DRUJ with concomitant distal ulnar degenerative changes ulnar head replacement indications severe ulnocarpal arthrosis salvage for failed Darrach outcomes early results are promising, long-term results pending Techniques Ulnar shortening osteotomy approach subcutaneous to ulna technique often combined with arthroscopic TFCC repair