August 1st, Scaphoid Fractures. Dr. Christine Walton, PGY 2 Orthopedics

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1 August 1st, 2006 Scaphoid Fractures Dr. Christine Walton, PGY 2 Orthopedics

2 Injury Patterns to the Carpal Bones 1) Perilunate pattern injuries 2) Axial pattern injuries 3) Local impaction/avulsion injuries

3 Perilunate Pattern Injuries injuries which occur in an arc around the lunate Includes # of the scaphoid, most capitate # and some triquetral #s Any # in the above bones should prompt a search for other injuries (joints/bones) along the perilunate injury pathway Classification = Unstable surgical intervention force = ligamentous injury Scapholunate joint Stage I = scapholunate dissociation Lunate Triquetrum Stage IV = lunate / perilunate dislocation radial deviation = arc around the lunate Mayfield et al.

4 Axial Pattern Injuries The result of powerful anteroposterior compression forces (explosion injury or severe crush) Injury pattern propagates in both the radial and ulnar direction separates the carpus on either side of the capitate Unstable requires surgical treatment

5 Local Impaction / Avulsion Injuries Isolated carpal bone injuries that occur due to localized force concentration Includes: Dorsal chip fractures of the triquetrum Trapezial ridge fractures Pisiform fractures Hamate hook fractures Avascular necrosis of carpal bones Kienbock s disease Preiser s desease AVN of the pisiform and capitate

6 Scaphoid Fractures Most commonly fractured carpal bone (80% incidence) 2 nd most common upper extremity fracture (1 st Distal radius) M/I : FOOSH, wrist extended Males > Females Ages Scaphoid fracture distribution Rare in children (distal 1/3) proximal 1/3. waist..65% 25% distal 1/3 10% Often mislabelled as just a sprain high index of suspicion needed

7 17% of patients with scaphoid #s have associated injuries: Transscaphoid perilunar dislocations Trapezium fractures Bennett fractures Radial head fractures Lunate dislocations Fractures of the distal radius

8 Anatomy of the Scaphoid 5 articulating surfaces (radius, lunate, capitate, trapezium, trapezoid) Shape: center of the distal articular surface is palmar to the proximal articular surface, resulting in the production of a flexion moment of the scaphoid with axial loading of the wrist Multiple ligamentous attachments almost entirely covered by cartilage

9 Blood Supply to the Scaphoid Extraosseous vessels enter the middle and distal portions of the scaphoid Proximal pole receives no direct vascular supply - intraosseous vessels pass retrograde from the waist

10 Obletz and Halbstein 67% of scaphoid bones have arterial foramina throughout their length, including the distal, middle, and proximal thirds 13% have blood supply predominantly in the distal third 20% have most of the arterial foramina in the waist area of the bone with no more than a single foramen near the proximal third 1/3 of scaphoid fractures occurring in the proximal third may be without adequate blood supply, and this seems to be borne out clinically prevalence of AVN can be as high as 35% in fractures at this level

11 Scaphoid arterial blood supply. The dorsalscaphoid branch (1) enters at the waist and supplies the proximal 70% 80% of the bone. The volar scaphoid branch of the radial artery (2) supplies the distal 20% 30%. Rettig AC. Managementof acute scaphoid fractures. Hand Clin 2000;16(3):382

12 Mechanism of injury failure of bone caused by a compressive or tension load Wrist extension < 35 = Fracture of the forearm > 90 = # of the carpal bones Wrist Extension Proximal pole locks in the scaphoid fossa of the radius Distal pole moves excessively dorsal Fractures of the scaphoid were consistently produced in fresh cadaver specimens when radial deviation was added to an extended wrist ( ), and force applied to the radial half of the palm Green s operative hand surgery, 2005

13 Distal fractures extension of the wrist Proximal fractures result from initial dorsal subluxation of the scaphoid before forced supination Waist fractures results when the palmar ligaments (radioscaphocapitate) act as a fulcrum on which the distal pole may flex palmarly

14 Investigations History (FOOSH) Physical Examination: Tenderness with Palpn over the scaphoid tubercle snuff-box with longitudinal compression Diagnostic sensitivity 100%

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16 Routine X-rays of the Scaphoid Posteroanterior - fingers flexed into a fist position to produce slight extension and ulnar deviation - places the longitudinal axis of the scaphoid in a plane more closely parallel with that of the film - accentuates a scapholunate gap (r/o injury) Lateral - helpful for evaluation of carpal alignment and determination of carpal instability Oblique (x2) *wrist slightly extended in ulnar deviation is helpful*

17 Routine X-ray Series for Scaphoid bone A-P Lateral Oblique pronation 45 Oblique supination 45

18 Navicular Fat Stripe (Scaphoid fat pad sign) A small radiolucent area normally present next to the scaphoid in A-P Radiographs A linear collection of fat b/w the radiocollateral ligament and the tendon sheaths of the Abductor pollicis longus and extensor pollicis brevis A fracture on the radial side of the wrist can either displace or obliterate this line Found to be a poor predictor of scaphoid fracture (Terry and Ramin)

19 $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ What management would you propose if there was no fracture identified on the x-ray?? $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

20 Primary Care,Volume 32, 2005

21 Bone scan sensitivity 100% specificity of 98% positive predictive value of 93% False -ve: traumatic synovitis S-L tear 2 weeks after the injury, a ve bone scan excludes a fracture. If +ve, CT scan or immobilize and repeat x-rays in 3 weeks Cost-effectiveness of diagnostic strategies for suspected #s: initial radiographs, with bone scan at 2 weeks. Teil-van Buul et al a bipartite scaphoid is considered so rare as to be of little or no clinical significance

22 J Bone Joint Surg Br 1984;66: The Herbert Classification of Scaphoid Fractures Type A: stable acute fractures A1. Fracture of tubercle A2. Incomplete fracture of the waist (middle third) Type B: unstable acute fractures B1. Distal oblique B2. Complete or displaced waist fracture B3. Proximal pole fracture B4. Trans-scaphoid perilunate dislocation fracture B5. Comminuted fracture Type C: delayed union Type D: established union D1. Fibrous nonunion (stable) D2. Displaced nonunion (unstable)

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24 Nondisplaced, Stable Scaphoid Fractures Acute Nondisplaced Stable fractures No bony / ligamentous injury In children Conservative Treatment * better prognosis with early diagnosis *

25 Treatment of Nondisplaced Stable # Cast Immobilization Expected rate of union, 90-95% in weeks Removable short arm thumb spica cast vs. Long arm thumb spica cast Delayed Dx or # in Proximal 1/3 = 6/52 Terkelsen and Jepsen N=92, P>0.05 (rate of nonunion) Gellman et al 6/12 LSC = 3/12 faster Serial X-rays Repeat x-rays q 1-3/52 to assess bone healing Collapse or angulation of the fractured fragments = Sx special nonoperative or operative treatment considerations for patient population

26 Displaced, Unstable Scaphoid Fractures Unstable Fracture: Fragments are offset > 1 mm in the A-P or oblique view OR if lunocapitate angulation is greater than 15 degrees OR scapholunate angulation > 45 in lateral view (N = ) Other Criteria a lateral intrascaphoid angle greater than 45 an A-P intrascaphoid angle less than 35 a height-to-length ratio of 0.65 or more

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28 Nonunion of Scaphoid Fractures Common causes: delayed Dx (~ 40%), gross displacement, assoc. injuries and impaired blood supply Delayed treatment (> 4wks) can result in a nonunion rates of 88%. The incidence of avascular necrosis is approximately 30% to 40% (usually involves the proximal third) The following operations can be used for nonunions: (1) radial styloidectomy (2) excision of the proximal fragment the distal fragment, and, occasionally, the entire scaphoid (3) proximal row carpectomy (4) traditional bone grafting (5) vascularized bone grafting (6) partial or total arthrodesis of the wrist.

29 Scaphoid Nonunion Advanced Collapse (SNAC) pattern.watson and Ballet Describes X-ray findings of arthritis usually seen with scaphoid nonunion: radioscaphoid narrowing capitolunate narrowing cyst formation pronounced dorsal intercalated segment instability (DISI) Radiolunate joint is usually spared as well as the proximal pole + corr. Radial surface Scapholunate Advanced Collapse (SLAC) Progressive arthritis due to SL interval disruption with Flx deformity of the scaphoid and DISI of the proximal carpal row Stage I: arthritis b/w the scaphoid and radial styloid Stage II: arthritis b/w the scaphoid and the entire scaphoid facet of the radius Stage III: Above, + arthritis b/w the capitate and lunate

30 Dorsal intercalated segmental instability(disi). Sagittal T1-weighted image shows the dorsal tilt of the lunate (longarrow) and proximal migration of the capitate (short arrow).

31 Scapholunate advance collapse (SLAC): endstage of SL instability. The SL ligament is torn and there is widening of the interval. There is advanced radiocarpal arthritis, proximal migration of the capitate, and midcarpal arthritis.

32 The inlay (Russe) graft Bone Grafts for Nonunion - union rate of 92% - not used for adjacent carpal collapse or humpback deformity Interposition (Fisk) graft - opening-wedge graft designed to restore scaphoid length and angulation - used to correct adjacent carpal instability - union rates of 72% - 95% Vascularized bone graft - a distal radius vascularized bone pedicle graft, 1-2 intercompartmental supraretinacular artery (ICSRA) - only used for difficult cases (previously failed grafts) - harvested from the distal radius - increased success when AVN involved

33 Decision-making for Treatment Options Duration: Acute fractures are defined as being less than 3 weeks old Delayed union is defined as failure to heal by 4 to 6 months Ununited fractures older than 6 months are considered nonunions Location: * prognostic implications Orientation: the plane of the fracture. Horizontal oblique, vertical oblique, and transverse fractures; Vertically oriented fractures are less stable and, consequently, less likely to heal. Displacement: > 1 mm stepoff on any view, a scapholunate angle of >60, a lunocapitate angle >15, or a lateral intrascaphoid angle > 20 (Dramatic affect on conservatively treated waist fractures) Comminution: Comminuted fractures are inherently unstable. Associated injuries: Scaphoid #s commonly accompany perilunate dislocations

34 Canale: Campbell's Operative Orthopaedics, 10th ed., Copyright 2003 Mosby, Inc. Surgical Approach to the Scaphoid The Volar approach best exposure for scaphoid fractures at and distal to the waist The Dorsal approach For noncomminuted fractures in the proximal pole of the scaphoid Intra-op The most reliable sign of vascular proximal pole is punctuate bleeding if obvious = union rate of 92% if questionable = union rate of 71% if no bleeding = union rate of 0%

35 Summary of Treatment Options Fresh stable undisplaced - Short arm / long arm TS cast - Percutaneous compression screw Fresh undisplaced Potentially unstable (vertical oblique or reduced Trans-scaphoid dislocations) Previously untx stable #s (older than 3 weeks) - Percutaneous compression screw fixation - long-arm/thumb spica cast Fresh displaced / angulated - ORIF (Kirschner wires or Herbert screw) Nonunions, asymptomatic stable (Strong likelihood of late OA) - Russ-type graft - Vascularized graft

36 Continued... Symptomatic nonunions without OA, AVN or Carpal collapse Vascularized graft with addition of Compression screw or russe-type graft Nonunions with carpal collapse (DISI) without OA or AVN Nonunions with limited OA without AVN Nonunions with definitive AVN Nonunions + extensive OA Anterior wedge bone graft with internal fixation (K-wires / herbert screw) or vascularized graft Bone Graft and limited styloidectomy or scaphoid excision + midcarpal fusion Vascularized bone graft or replacement of the Proximal fragment with soft tissue or scaphoid excision and midcarpal arthrodesis Excision of the scaphoid with midcarpal arthrodisis or total wrist arthrodesis

37 Post-op Treatment Immobilization in an elbow-to-thumb spica cast (6-8 wks) + / - Kirschner wires are removed at 6 to 8 weeks Screw fixation can be left in place permanently unless tender At 6 to 8 weeks, a short arm thumb spica cast is applied After cast removal wrist motion and elbow motion are increased gradually, followed by strengthening exercises.

38 The END