Distal Radius Shortening as a result of Fracture - Philippa Rust 14/5/2005Normal measurements
Distal Radial Length
Acceptable Reduction
Management When radial shortening is due to comminution, then external fixation maybe the most reliable method of restoring length; Change in Ulnar Variance Functional anatomy In neutral variance, 80% of load is born by radius and 20% by ulna 2 mm increase in ulnar variance will increase load borne by ulno-carpal joint from 18% to 42% 2.5 mm decrease in the ulno-carpal variance will decrease the load borne by the ulno-carpal joint to 4.3% Effect of positive ulnar variance Fibrocartilage complex abnormalities. (TFCC) Significant loads are transmitted to the forearm unit through the distal ulna via the triangular fibrocartilage complex. The anatomic relationships between the distal radius and ulna and ulnar carpus are precise, and even minor modification in these relationships leads to significant load changes and resultant pain syndromes Palmer m-A-K. Hand-Clin. 1987 Feb. 3(1). P 31-40.
ulnar side of the wrist is supported by the TFCC, which articulates w/ both the lunate and the triquetrum; TFCC is prone to injury due to the axial and shear forces that are applied to it as the carpi rotate over the radius and ulna; Therefore with disruption of the normal smooth surface between the ends of the radius & ulna the TFCC is prone to tears
positive ulnar variance or non union of distal ulnar fracture Positive ulnar variance leads to loading of the ulnocarpal joint and resultant Lunotriquetral Dissociation, lunate chondral lesion, (and TFCC tears ) Exam Findings: positive ulnar stress test; tenderness with direct palpation of the ulnar carpal joint; Radiographs : radiographic findings may be subtle; may show flattening, subchondral sclerosis, and/or lytic changes in lunate and/or triquetrum with similar changes seen over the distal ulna; patients may have increased ulnar variance ; in subtle cases, a pronation grip radiograph may demonstrate ulnar variance; bone scan may be positive; Lunotriquetral ligament tears & Lunotriquetral Dissociation Ulnar side carpal instability; Involves disruption of lunotriquetral & volar radiolunotriquetral ligaments & attentuation or rupture of dorsal radiotriquetral attachments with a isolated tear of the LT interosseous ligament, There will be only a small amount of increased motion, however, even this is enough to cause symptoms; Mechanism: may occur as result of positive ulnar variance injury occurs w/ forced extension or extension-radial deviation, as scaphoid induces the lunate into a further flexion stance while triquetrum extends; w/ advanced injury, lunotriquetral, volar radiolunotriequetral, & dorsal radiotriquetral ligaments are torn; VISI collapse deformity develops; Other causes of positive ulnar variance: previous excision of radial head increasing age may develop in child gymnasts, due to "stress related changes" in the distal radial physis; and chronic compressive loads borne by the radius, leads to premature closure of the distal radial physis; Negative ulnar variance is associated w/ Kienbock's disease Treatment Avoid mal-union of distal radius fractures, accurate reduction and fixation: use of locking plates or external fixators (non-bridging McQueen). Correction osteotomy of distal radius, opening wedge and rigid buttress plate fixation young patients only, complex procedure, Jupiter advises caution Distal ulnar arthroplasty: selection depends on: slope of the distal RU joint surface whether it is congruent (an incongruent joint might be made congruent with an oblique ulnar shortening); whether it has degenerative changes (in which case, a resection arthroplasty or Sauve-Kapandji may be indicated); Ulnar shortening/ realignment osteotomy – Most indicated for ulnar impaction syndrome ; this procedure unloads the distal ulna, and thereby relieves distal ulnar impingement symptoms; Osteotomy may be performed using a transverse, oblique, or step cut osteotomy Wafer procedure – a wafer of upto 2-4 mm of distal ulnar head is removed, while the styloid process TFCC , and attached ligaments remain attached; the procedure is contra-indicated if more than 4 mm of positive variance; may be indicated for symptomatic positive ulnar variance , ulnocarpal impaction syndrome , or symptomatic TFCC tears ; some authors feel that for this procedure to be successful, the TFCC must be intact; Bower’s procedure involves resection of ulnar articular head, leaving shaft and styloid relationship intact. It may be indicated to restore passive pronation and supination of the forearm. Darrach procedure - for symptomatic malunion of Colle's frx in elderly patients, low demand patient, especially when stiffness is present; Sauve-Kapandji Procedure is indicated for arthritic RU Joint w/ limitation of motion it can also be used following malunion of fractures resulting in arthritis as long as ulna is shortened as part of the procedure: osteotomy: performed just proximal to the RU joint articular cartilage, or just proximal to the flare of the ulnar head; a second cut is made 15 mm proximal to the first cut and the segment of ulna is removed; RU joint articular cartilage is removed & ulnar head is applied to the radius and is held. Wrist fusion Ulnar Sided Wrist Pain, osseous related pain: hamate fracture ; pisiform fracture or OA , ulnar styloid frx , base of the fifth metacarpal TFCC , distal radioulnar joint (DRUJ) , radioulnar joint instability , ulnocarpal impingement syndrome carpal instability : , triquetrolunate instability; mid carpal instability , vascular related pain : hypothenar hand syndrome , neurologic related pain: ulnar nerve entrapment at Guyon's canal , ulnar dorsal sensory branch neuritis; tendon related pain: extensor carpi ulnaris tendonitis., flexor carpi ulnaris International Distal Radius Study Group http://www.eradius.com/ RADIAL SHORTENING : 1 BIOMECHANICAL STUDIES a) Pogue, Viegas, Patterson, et al. (1990, JHS) method: five cadavers, pressure-sensitive film, examine contact areas and pressures results: 2 mm shortening created statistically significant increase in the lunate contact areas b) Adams (1993, JHS) method: six cadavers results: radial shortening was the most significant change affecting the kinematics of the DRUJ and the TFC 2 CLINICAL STUDIES a) Jupiter and Masem (1988, Hand Clinics) review article, Reconstruction of Post-Traumatic Deformity of the Distal Radius > 6 mm of shortening caused DRUJ pain, decreased pro- and supination radial shortening most disabling of malunited fractures b) McQueen (1988, JBJS[B]) 30 patients with Colles' fracture, four year follow-up > 2 mm shortening statistically significant increase in symptoms in terms of strength, ADL, ROM, and pain c) Jenkins (1988, JHS) prospective study of 61 consecutive patients treated with closed reduction, cast immobilization mean shortening was 4.0 mm strong correlation between radial length and strength and ROM mean radial shortening in patients with pain: 4.7 mm mean radial shortening in patient without pain: 2.3 mm (statistically significant) d) Kopylov (1993, JHS[B]) retrospective review of 76 patients, 26-36 years after distal radius fracture, average follow-up of 30 years radial shortening most important factor after intraarticular step-off 1 mm radial shortening had a 50% increased risk of DJD in the DRUJ 1 mm radial shortening had a 20% increased risk of DJD in the RC joint 2 mm radial shortening had a 50% increased risk of DJD in the RC joint 3 RECOMMENDATIONS Weiland (OKU-Trauma, AAOS, 1996) Accept no > than 2 mm radial shortening ASSH Regional Review Course (1994) Accept no > than 3 mm radial shortening ASSH Specialty Day at AAOS (Trumble, 1999) Accept no > than 2 mm radial shortening Kopylov (1993, JHS[B], 30 year follow-up study) Goal: no > than 1 mm radial shortening Baratz (ASSH Specialty Day at AAOS, 1998) Accept no > 5 mm radial shortening 3 mm or less is optimal
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