COMPREHENSIVE MANAGEMENT OF SOFT-TISSUE INJURIES ASSOCIATED WITH DISTAL RADIUS FRACTURES BY DEAN W. SMITH, MD, AND MARK H. HENRY, MD Distal radius fractures can no longer be thought of in isolation. Increasing recognition is being given to the associated soft-tissue injuries that include: median nerve compression, radioulnar ligament injury, fibrocartilage disc substance tear, volar extrinsic ligament injury, dorsal extrinsic ligament injury, and intrinsic ligament injuries. Diagnosis, classification, and management of the associated soft-tissue injuries can be accomplished with a combination of endoscopic and arthroscopic techniques that balance well with current methods of distal radius fixation. The use of these less invasive but stable techniques facilitates an early rehabilitation program with the long-term goal of improved function. Copyright © 2002 by the American Society for Surgery of the Hand he management of distal radius fractures has results in the long term.1,2 Most classifications used evolved substantially over the past several de- for distal radius fractures hint at but do not directly Tcades. More surgeons are now agreeing on the address the pattern of associated soft-tissue injuries. importance of stable internal fixation, and increased The Frykman, Melone, Mayo, Universal, and AO clas- recognition is being given to the assessment and sification systems are all ultimately based on the pat- management of associated soft-tissue injuries. It is tern of the fracture lines. The Jupiter and Fernandez3 these injuries that often account for unsatisfactory classification is based on the mechanism of injury and thus at least indirectly suggests which soft-tissue in- juries may be present. A method of documenting the From the Houston Hand and Upper Extremity Center; and the associated soft-tissue injuries that tie them to existing Department of Orthopaedics, University of Texas School of Medicine, classifications for radius fractures would be of partic- Houston, TX. ular benefit in judging outcome reporting from dif- Address reprint requests to Dean W. Smith, MD, The Houston Hand and Upper Extremity Center, 1200 Binz St, Suite 1350, Houston, ferent centers during comparative literature assess- TX 77004. ment (Table 1). Overlooking the associated soft-tissue injuries in the past may be owing to less rigorous Copyright © 2002 by the American Society for Surgery of the Hand 1531-0914/02/0203-0005$35.00/0 assessments of outcome or because prolonged immo- doi:10.1053/jssh.2002.34797 bilization in casts or external fixators failed to show JOURNAL OF THE AMERICAN SOCIETY FOR SURGERY OF THE HAND ⅐ VOL. 2, NO. 3, AUGUST2002 153 154 SOFT-TISSUE INJURIES ⅐ SMITH & HENRY Median Nerve Compression TABLE 1 Median nerve compression in distal radius fractures Soft-Tissue Addendum Classification can occur in the acute, subacute, or late setting with Nerve Posttraumatic nerve compression a reported incidence of up to 8%.7 The incidence, requiring urgent surgical however, may be even higher in more severe, high- decompression and serving as the prime determinant of surgical timing energy, intra-articular injuries. In vivo carpal canal Intrinsic Intrinsic ligament rupture with instability pressure studies show an acute increase in pressure requiring open or arthroscopic repair within the canal before fracture reduction and for over with pinning 8 Extrinsic Extrinsic ligament rupture with instability 12 hours after reduction. Historically, treatment of requiring open or arthroscopic repair median nerve compression with associated distal ra- with pinning dius fractures has been controversial. Axelrod and Radioulnar Radioulnar ligament rupture with 9 instability requiring open or McMurtry noted common complaints of median arthroscopic repair with pinning nerve compression symptoms after open reduction and NOTE. Each letter would be added after the designation internal fixation with either a dorsal or volar approach given for the classification of the radius fracture itself. Strat- in patients with high-energy trauma and associated ification thus allows research outcomes to more fairly reflect soft-tissue wrist injuries. Subsequent prophylactic car- the magnitude of injury and give meaning to comparison between patients treated in different series by different in- pal tunnel release was recommended. vestigators (ie, if the Fernandez classification were chosen Three different injury scenarios may exist with the as the base classification, a fracture with combined mech- median nerve. First, the nerve may suffer a ballistic anisms and a high degree of comminution with a concomi- tant perilunate dislocation and radioulnar dissociation would contusion injury at the moment of impact and show be coded as a Fernandez type 5,I,R). diminished function thereafter. In this clinical situa- tion, the nerve will not be aided by decompression and is expected to recover spontaneously. The second sce- nario is that of no apparent initial injury, but as the soft-tissue deficiencies during the initial aftercare. swelling develops over hours to days the nerve be- Current trends in radius fracture management include earlier and more aggressive motion protocols. In this comes critically compressed. Surgical release of the setting, soft-tissue injuries become more apparent. transverse carpal ligament will decompress the me- The following potential injuries should be assessed as dian nerve. The third scenario is that of initial con- part of the evaluation and management of a distal cussive injury that shows diminished function on radius fracture: (1) median nerve compression; (2) physical examination from the outset that then masks radioulnar ligament injury; (3) fibrocartilage disc sub- the evolving compartment syndrome in the carpal stance tear; (4) volar extrinsic ligament injury; (5) canal. This scenario is the most dangerous and is dorsal extrinsic ligament injury; and (6) intrinsic lig- sometimes missed, resulting in a permanent deficit. ament injury. Considering the earlier-mentioned pitfalls, minimally The rates of associated soft-tissue injury identified invasive surgical decompression of the median nerve is at the time of fracture surgery continue to be quan- indicated in situations in which the physical exami- tified.2,4 Furthermore, definitive classifications for nation reveals lost nerve function to a degree that each of these injury patterns have not been agreed on suggests permanent nerve damage may result. Deter- universally, although the biomechanics of each injury mining when this threshold has been reached is dif- and its consequences have been defined.5,6 ficult. Serial examinations with monofilaments are performed to quantify sensibility. The inability to SURGICAL CONSIDERATIONS perceive the 4.31-g monofilament is suggestive of significant median nerve dysfunction. uantitative motor and sensory testing are used to After surgery, the degree of swelling may increase Qjudge the involvement of the median nerve. The the pressure on the median nerve above preoperative other 5 soft-tissue injuries are diagnosed and levels. In cases involving high-energy injuries and graded through combined physical stress testing and complicated reconstructions, it is often wise to decom- arthroscopic examinations. press the median nerve, even when the preoperative SOFT-TISSUE INJURIES ⅐ SMITH & HENRY 155 physical examination showed limited abnormalities. the torn fibrocartilage flap, which may be performed The endoscopic technique may be safely used and is, with equal success at a later date. The injury described in fact, simpler after acute trauma than in elective in this section is a Palmer type IA fibrocartilage tear cases when abundant synovitis can obscure visualiza- (Fig 2). True Palmer type IB and ID lesions are tion of the transverse carpal ligament fibers. Open actually radioulnar ligament injuries. Palmer type IC decompression is also a viable alternative. lesions are volar extrinsic ligament injuries. Radioulnar Ligament Injury Volar Extrinsic Ligament Injury Perhaps one of the most poorly understood wrist True volar extrinsic ligament injuries in association ligaments is the radioulnar ligament. Previous studies with distal radius fractures are exceedingly rare. The have reached seemingly opposing conclusions over the pattern of injury that may be more frequently encoun- importance of the dorsal and volar bundles for distal tered is a shearing pattern of fracture dislocation of the radioulnar joint stability in pronation and supina- radiocarpal joint, as described by Jupiter and Fernan- tion.10-12 A recent biomechanical study found that the dez.3 A pure fracture dislocation of the joint may dorsal and volar bundles of the radioulnar ligament appear to have taken place, however, there is usually a function in concert such that each cannot be consid- small volar fragment that carries the origin of one or ered independently.13 When associated with a distal more volar extrinsic ligaments (radioscaphocapitate, radius fracture, injuries to this ligament complex oc- long radiolunate, short radiolunate). Direct reduction cur in 3 patterns. The ulnar styloid may fracture at its and stabilization of the small bony fragment and the base and be carried radially with the ligament because associated volar ligaments re-establishes stability. Pin- it displaces according to movement of the sigmoid ning across the radiocarpal joint for 4 weeks may still notch (most frequent). If unstable, reduction and ten- be a necessary adjunct to avoid subluxation or failure sion band wiring around 2 K-wires (0.035