Radius and Scaphoid Fractures

Transcription

1 Page 1 of 7 Return to the Table of Contents Site Map Your Account Support About Us Marketplace Offerings: Medscape.com Charts Mobile Logician CBSHealthwatch American Academy of Orthopaedic Surgeons Annual Meeting Day 4 - March 18, 2000 Radius and Scaphoid Fractures Ralph Purcell, MD Longitudinal Instability of the Forearm Introduction Radial head and neck fractures require continued attention because of the number of associated short and long-term complications of the elbow and wrist. At the American Orthopaedic Society for Sports Medicine (AOSSM) Specialty Day Meeting, Dr. Robert Hotchkiss [1] explained the importance of radial neck and head fractures to both elbow and wrist function. He discussed the pathophysiology of such fractures and provided a practical classification system with the practitioner in mind. Treatment options were discussed for each of the fracture patterns and suggestions were made for maximizing functional outcome following the proximal radius fracture. A discussion of radial head and neck fractures needs to begin with a look at the interosseous membrane, a structure that must be considered as a ligament transferring forces across the forearm. It is this property that leads to concomitant wrist pathology when radial neck/head fractures are associated with IOL (interosseous ligament) incompetency. The triangular fibrocartilage complex (TFCC) tears, the ulna styloid impacts on the ulnar carpus, and the distal radio-ulnar joint becomes deranged. Furthermore, ulno-carpal instability can arise. When chronic Essex-Lopresti lesions are corrected, the IOL remains incompetent because it becomes scarred and loses its normal load-transferring properties. As a result, attention to rapid restoration of the radial length is indicated for long-term forearm function. Dr. Hotchkiss has modified the Mason x-ray classification of radial neck/head fractures to determine appropriate treatment parameters: Classification Definition Type I Nondisplaced or mildly displaced fractures of the radial head or neck Clinical Characteristics No mechanical block but may have decreased pronation and supination secondary to acute pain and/or swelling Treatment Requires early mobilization without cast treatment to avoid elbow and forearm contractures Type II Displaced (>2 May have Usually require open

2 Page 2 of 7 mm) fractures of the head or neck (angulated) incongruity at the fracture site and mechanical blockage to movement. Normally encompasses more than a marginal lip of the radial head. Lack severe comminution. reduction and internal fixation (ORIF) but may benefit from excision in select circumstances such as the elderly. If radial neck comminution is present, then consideration of bone grafting is warranted. During the ORIF procedure, care needs to be given to avoiding the posterior lateral corner to avoid posterior lateral elbow instability. Type III Severely comminuted fracture of the radial head and neck Associated with adjacent injuries such as TFCC tears, IOL tears of the forearm, or elbow dislocations (usually posterior) with or without choronoid fractures. Need to be excised for restoration of forearm movement. Tears of the IOL are associated with type II and III fracture patterns and when diagnosed acutely, require ORIF of the radial head, if possible. Conversely, type II fractures associated with IOL disruption require a prosthesis to prevent proximal migration of the radius. In the past, silicon prostheses, allografts, or metallic prostheses, such as titanium, have been used to prevent such migration. Allograft radial heads are now associated with late fragmentation and failure. Silicon prostheses with sufficient cyclical loading lead to compression deformity and thus lose the ability to maintain longitudinal forearm stability. Even the titanium prosthesis has a 10% failure rate associated with loosening. After application of the prosthesis, pinning the wrist in supination for 4 weeks is desirable to help re-establish the distal radio-ulnar joint complex. Repair of concomitant TFCC tears should also be considered to maximize ulno-carpal stability. Delayed treatment of ulnar positive deformity associated with IOL injury remains controversial and fraught with unpredictability. Radial-ulnar synosthosis, a salvage procedure, is disabling, as it permanently limits forearm rotation. Frozen radial head allografts following Ilizarov lengthening is both time-consuming and of unknown durability. Replacement of IOL with bone-tendon-bone is still experimental and unreliable. Titanium radial head prostheses remain the most reliable option at this time. It is important to recognize that the radial head/neck fixation in low-demand individuals without Essex-Lopresti injuries or without high-energy injuries does not require radial head replantation. The treating physician must nevertheless look for signs and symptoms of IOL

3 Page 3 of 7 injury, such as soreness in the forearm and swelling at the distal radio-ulnar joint. In addition, one must be aware of late radial migration. Scaphoid Fractures Nonoperative Treatment Although scaphoid fractures are common, their treatment remains controversial. Dr. Richard L. Uhl [2] discussed nonoperative treatment options for scaphoid fractures, which include the type of cast mobilization, duration of mobilization, role of electrical stimulation, and time to healing. Anatomy drives the healing potential of scaphoid fractures. The vascularity of the scaphoid remains precarious, with blood vessels only on the dorsal ridge and tuberosity. The sole blood supply to the proximal pole is endosteal and retrograde because the proximal pole is intraarticular and cartilaginous. Healing is most rapid where blood flow is greatest and progressively diminishes closer to the proximal pole. Stability also varies according to location. Scaphoid tuberosity fractures and incomplete waist fractures maintain the greatest stability, while complete waist fractures tend toward humpback deformity and collapse with subsequent carpal collapse (DISI). The proximal pole fractures are associated with the least stability. Stability can be assessed with PA and ulnar deviation PA x-rays. Lateral x-rays best reveal carpal instability patterns. If greater than 1 mm displacement is present on x-ray evaluation, then instability is likely. Visualization of incomplete waist fractures or humpback deformity is likely to require computed tomography (CT) scan evaluation in the plane of the long axis of the scaphoid. Once the goals of cast immobilization are clarified, then decisions about duration and type of immobilization can be made. Casting cannot stabilize an unstable fracture or reduce a displaced fracture, nor can it encourage blood supply to the scaphoid. The cast only protects the fracture site from outward trauma and immobilizes the stable fracture, hopefully allowing healing. As of 2000, different fractures require different immobilization treatment. Acute scaphoid tuberosity fractures usually require 4 to 6 weeks for healing, while stable incomplete waist fractures usually require 8 to 10 weeks. Patients with clinical signs of scaphoid fracture but negative initial radiographs may benefit from CT scan evaluation to determine whether a fracture line is present. Conversely, a short-arm cast or splint can be used for 2 weeks until a repeat radiograph is obtained. Long-arm thumb spica casting is advocated for the first 4 weeks followed by short-arm thumb spica casting for 4 to 6 weeks as needed. The thumb spica component further immobilizes the fracture and helps limit load transference across the fracture site. If no healing occurs by 10 weeks, then consideration of operative treatment is warranted. Similarly, if fracture displacement or intercarpal displacement such as a DISI pattern occurs, then surgical care should be pursued. Operative Management Dr. Fischer, [3] of Indiana University School of Medicine and the Indiana Hand Center, discussed ORIF of scaphoid fractures. He reiterated Osterman's 1988 statement that rigid fixation of the scaphoid is required to correct the deformity. He stressed that the anatomy

4 Page 4 of 7 dictates treatment, both in axis of hardware and starting position of fixation devices. The isthmus, or waist of the scaphoid, is narrowed by dense subcortical bone and thus the direction of the fixation device is further limited. The marginal blood supply into the scaphoid further forces exacting consideration of the entry point for the fixation device. Articular surfaces must not be penetrated by overly long implants. Before consideration of surgery, the exact nature of the fracture must be assessed. Fracture comminution as well as fragment size and alignment can best be assessed with CT scan visualization. Pre-operative planning further improves radiographic templating, which helps determine appropriate size of the implant and the correct intrascaphoid angle. Intraoperatively, real-time fluoroscopy is required, and the screw threads of the implant must not cross the fracture site. The screw fixation must target the largest bone mass. The hand is left supine on a radiolucent hand table with C-arm availability. Fingertip distraction of 5 to 10 pounds is attached to the thumb and index to create ulnar deviation, scaphoid extension, as well as distraction of the fracture site and capsule tension. Lastly, a "bump" is used under the ulna to prevent scaphoid flexion. The choice of implant is varied from K-wires to an array of headless screws to compression AO cannulated screws with a threaded washer assembly. Cannulated screw fixation allows limited capsulotomy while headless screws with jigs require a larger arthrotomy/capsulotomy. Joysticks are helpful in manipulating and reducing the intrascaphoid angle, axial rotation and frontal plane deformities. Reduction is performed with traction but stabilization is pursued without traction. The need for osteotomizing the extraarticular margin of the trapezium at the STT joint was stressed for ease of jig placement. A dorsal approach through the third dorsal compartment was suggested for small proximal pole fragments. The need to avoid penetrating the dorsal ridge was stressed, as was the need to supply forcible wrist flexion at the time of implant placement. Dr. Fischer concluded with a discussion of recommended aftercare. He felt that 4 weeks of cast immobilization with solid fixation was necessary, but that serial x-ray evaluation might necessitate further casting. He felt that sports could be resumed with appropriate healing at 3 to 4 weeks, provided that fracture protection was available. Arthroscopic Management Dr. William Bennett Geissler [4] discussed percutaneous and arthroscopic screw fixation of scaphoid fracture as an alternative to closed management or traditional open treatment. He felt that atrophy, disuse, osteopenia, soft-tissue trauma of traditional surgery, and even financial hardship could possibly be ameliorated with more rapid surgical treatment in some patients, using a limited approach. Dr. Geissler acknowledged that previous studies revealed a high incidence of associated injury with scaphoid fractures. Thus, repair could conceivably be pursued simultaneously with scaphoid fracture treatment. Of note, only nondisplaced or minimally displaced but reducible scaphoid fractures were considered appropriate candidates for this procedure. In the procedure, a 1.5-cm incision over the volar tubercle of the trapezium just radial to the flexor carpi radialis is made. The scapho-trapezial joint is exposed through a T-shaped incisiion and the volar tubercle is then excised. The wrist is suspended for the arthroscopic component of this procedure and the radial-carpal and mid-carpal joints are visualized. The

5 Page 5 of 7 scaphoid fracture line is visualized and reduction with joysticks initiated. Once the reduction is confirmed, the alignment guide is utilized with the target hook placed 1 to 2 mm from the scapho-lunate ligament along the dorsal ligament of the proximal pole. The guide pin is then placed, its position evaluated with fluoroscopy, and the appropriately sized Herbert/Whipple screw is placed. Postoperatively, the wrist is splinted for 1 week, after which range of motion exercises are initiated. Athletes can return to sports in a protected splint 1 to 2 weeks following surgery, but proximal pole fractures require an additional month of immobilization before initiation of movement. Dr. Geissler noted healing rates similar to traditional open reduction and internal fixation, but with significantly reduced immobilization times. Whipple [5] reported radiographic healing within an average of 8.2 weeks, and Carlson reported union at 6 weeks in 12 of 13 patients with acute nondisplaced scaphoid fractures managed by percutaneous reduction using a dorsal approach. References 1. Hotchkiss R. Longitudinal instability of the forearm. From the 67 th annual meeting of the American Academy of Orthopaedic Surgeons (ASSH); March 15-19, 2000; Orlando, Fla. 2. Uhl RL. Treatment of scaphoid fractures with cast immobilization. From the 67 th annual meeting of the American Academy of Orthopaedic Surgeons (ASSH); March 15-19, 2000; Orlando, Fla. 3. Fischer TJ. Scaphoid fractures: open reduction and internal fixation. From the 67 th annual meeting of the American Academy of Orthopaedic Surgeons (ASSH); March 15-19, 2000; Orlando, Fla. 4. Geissler WB. Percutaneous and arthroscopic screw fixation of scaphoid fractures. From the 67 th annual meeting of the American Academy of Orthopaedic Surgeons (ASSH); March 15-19, 2000; Orlando, Fla. 5. Whipple TL. The role of arthroscopy in the treatment of wrist injuries in the athlete. Clin Sports Med. 1998;17: Suggested Readings Longitudinal Instability of the Forearm Hotchkiss RN, An KN, Sowa DT, Basta S, Weiland AJ. An anatomic and mechanical study of the interosseous membrane of the forearm: pathomechanics of proximal migration of the radius. J Hand Surg. 1989;14A: Rabinowitz RS, Light TR, Havey RM, Gourineni P, Patwardhan AG, Sartori MJ, Vrbos L. The role of the interosseous membrane and triangular firbrocartilage complex in forearm stability. J Hand Surg. 1994;19A: Knight DJ, Rymaszewski LA, Amis AA, Miller JH. Primary replacement of the fractured radial head with a metal prosthesis. J Bone Joint Surg Br. 1993;75: Edward GS, Jupiter JB. Radial head fracture with distal radioulnar dislocation: Essex-

6 Page 6 of 7 Lopresti revisited. Clin Orthop. 1988;234: Sowa DT, Hotchkiss RN, Weiland AJ. Symptomatic proximal translation of the radius following radial head resection. Clin Orthop. 1995;317: Geel CW, Palmer AK, Ruedi T, Leutenegger AF. Internal fixation of proximal radial head fractures. J Orthop Trauma. 1990;4: Scaphoid Fractures Clay NR, Dias JJ, Costigan PS, Gregg PJ, Barton NJ. Need the thumb be immobilised in scaphoid fractures? A randomised prospective trial. J Bone Joint Surg Br. 1991;73: Gellman H, Caputo RJ, Carter V, Aboulafia A, McKay M. Comparison of short and long thumb-spica casts for non-displaced fractures of the carpal scaphoid. J Bone Joint Surg Am. 1989;71: Linscheid RL, Weber ER. Scaphoid fractures and nonunion. In: Cooney WP, Linscheid RL, Dobyns JH, eds. The Wrist: Diagnosis and Treatment. St. Louis, Mo: Mosby; 1998: Operative Management Inoue G, Shionoya K. Herbert screw fixation by limited access for acute fractures of the scaphoid. J Bone Joint Surg Br. 1997;79B: Low CK, Ang BT. Herbert screw fixation of scaphoid fractures. Hand Surg. 1999;4: Rettig M, Raskin K. Retrograde compression screw fixation of acute proximal pole scaphoid fractures. J Hand Surg. 1999;24A: Arthroscopic Management Osterman AL. Wrist arthroscopy. In: Green D, ed. Operative Techniques in Hand Surgery. Philadelphia, Pa: Churchill-Livingstone; 1999: Taras JS, Sweet S, Shum W, Weiss LE, Bartolozzi A. Percutaneous and arthroscopic screw fixation of scaphoid fractures in the athlete. Hand Clin. 1999;15: Haddad FS, Goddard NJ. Acute percutaneous scaphoid fixation--a pilot study. J Bone Joint Surg. 1998;80: Inoue G, Shionoya K, Kuwahata Y. Herbert screw fixation for scaphoid nonunions: an analysis of factors influencing outcome. Clin Orthop. 1997;343: Slade JF, Mahoney JD. Carpal fractures and dislocations--00percutaneous treatment of scaphoid fractures. In: Plancher K, ed. Master Cases: Hand and Wrist Surgery. New York, NY: Thiemia Publishing; In press. Geissler WB, Freeland AE, Weiss APC, Chow JC. Techniques of wrist arthroscopy. J Bone

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