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Average 4.1 of 48 Ratings
A 22-year-old male snowboarder falls on an outstretched hand and presents with the radiograph shown in Figure A. Which of the following techniques is MOST important in optimizing biomechanical fixation?
Using a longer screw placed in the central axis of the scaphoid
Using a supplementary K-wire transfixing the distal pole of the scaphoid to the capitate
Using a longer screw placed in the dorsal axis of the scaphoid
Using a larger diameter screw placed in the dorsal axis of the scaphoid
Using a larger diameter screw placed in the volar axis of the scaphoid
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Several studies have shown a longer screw placed in the central axis of the scaphoid optimizes biomechanical fixation of scaphoid waist fractures. Many studies have discussed the amount of compression generated by various internal fixation screws (e.g headless vs. headed, variable pitch, partially vs. fully threaded, cannulated vs. noncannulated), but it is believed that rigidity of fixation is probably the most important factor in promoting healing of scaphoid fractures.
The first reference by McCallister et al is a cadaveric, biomechanical study that demonstrated a centrally placed screw had 43% more stiffness than an eccentrically placed screw. They recommend using surgical techniques that optimize central placement and screw length, such as using a cannulated screw.
The study by Dodds et al supported these findings and added that a longer screw with 2mm of bone coverage provided greater stability than a shorter screw. A more centrally placed screw is generally longer and has more length of screw on each side of the fracture than does a peripherally placed screw due to the anatomic dimensions of the scaphoid.
McCallister WV, Knight J, Kaliappan R, Trumble TE
J Bone Joint Surg Am. 2003 Jan;85-A(1):72-7. PMID: 12533575 (Link to Abstract)
McCallister, JBJS 2003
Dodds SD, Panjabi MM, Slade JF
J Hand Surg Am. 2006 Mar;31(3):405-13. PMID: 16516734 (Link to Abstract)
Dodds, JHS 2006
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Average 2.0 of 48 Ratings
An open dorsal approach for antegrade screw fixation of a nondisplaced scaphoid waist fracture differs in which of the following ways compared to a percutaneous dorsal approach?
Decreased risk of proximal pole AVN
Increased risk of posterior interosseous nerve injury
Decreased risk of injury to the APL tendon
Increased risk of injury to the EPL tendon
Decreased risk of screw prominence above subchondral bone
Scaphoid screw fixation should be just below the subchondral bone; this is best judged by direct visualization.
Adamany et al in an anatomic study using fluoroscopy to insert a scaphoid screw via a percutaneous approach found that the scaphoid screw "was prominent (above the subchondral bone) in 2 of 12 specimens and flush with or buried in the remaining 10 specimens." As a result, they recommend using a limited dorsal incision to verify full seating of the screw. In addition, they found the percutaneous approach was within 2.2-3.1 mm of the PIN, EDC, and EIP. Thus, all of these structures are at increased risk of injury in a percutaneous approach. The APL tendon is not in the surgical field. Illustration A shows the AIN(arrowhead) is deep in relation to pronator quadratus. Sensory remnant of posterior interosseous nerve (straight thick arrow) is adjacent to interosseous membrane. White arrow is median nerve. Shaded open arrow is ulnar nerve, and long thin arrow is superficial radial nerve.
Tumilty et al inserted a Herbert screw through a dorsal approach in 12 cadaveric wrists. They then imaged them with AP/Lateral xrays, and 360 degree fluoroscopic views. The wrists were then dissected to evaluated for subchondral penetration, and plain x-ray films were accurate in 5 of 6 specimens. Fluoroscopy was accurate in all 6. They concluded that fluoroscopy during placement of the Herbert screw may decrease the rate of subchondral penetration.
Adamany DC, Mikola EA, Fraser BJ
J Hand Surg Am. 2008 Mar;33(3):327-31. PMID: 18343286 (Link to Abstract)
Adamany, JHS 2008
Tumilty JA, Squire DS.
J Hand Surg Am. 1996 Jan;21(1):66-8. PMID: 8775197 (Link to Abstract)
Tumilty, JHS 1996
Average 2.0 of 26 Ratings
Which of the following statements is TRUE about force transmission based on wrist position?
neutral wrist position decreases force through the lunate fossa
extended wrist position increases force through the lunate fossa
neutral wrist position increases force through the scaphoid fossa
extended wrist position increases force through the scaphoid fossa
wrist position has no effect on force transmission
With the wrist extended force transmission is shifted to a greater extent through the scaphoid and the scaphoid fossa.
The position of the wrist can change the pattern of force transmission across the joint. With the wrist in neutral force is transferred across the joint via the lunate fossa and scaphoid fossa almost equally (slight predominance to the scaphoid fossa). However, with the wrist extended force transmission is shifted to pass even more via the scaphoid fossa, and less via the lunate fossa. This is a proposed explanation for scaphoid fractures resulting from falls onto an outstretched hand with the wrist extended.
Majima et al. tested force transmission through the wrist in different positions in a 3 dimensional rigid body spring model from CT images. They found that force through the scaphoid fossa increased from 52% to 62% with extension of the wrist (p<0.5). Similarly, in the midcarpal joint force transmitted across the scaphoid increased from 60% to 69% (p<0.5).
Weber et al. performed a cadaveric study of wrist injury. They found that with the wrist extended, the force applied to the palm was increased 4 times as it transmitted across the scaphoid. They describe the waist of the scaphoid as a location of concentrated force and theorize this is why waist fractures are common in injuries with wrist extended.
Answers 1, 2, 3, 5: These do not appropriately describe force transmission based on wrist position.
Majima M, Horii E, Matsuki H, Hirata H, Genda E
J Hand Surg Am. 2008 Feb;33(2):182-8. PMID: 18294538 (Link to Abstract)
Majima, JHS 2008
Weber ER, Chao EY.
J Hand Surg Am. 1978 Mar;3(2):142-8. PMID: 556476 (Link to Abstract)
Weber, JHS 1978
Average 3.0 of 30 Ratings
Percutaneous screw fixation for non-displaced scaphoid waist fractures has been shown to have which of the following differences compared to closed treatment?
Increased direct and indirect cost
Slower return to work
Higher union rates
Reduced time to fracture union
Improved motion and grip strength after 2 years
Fixation of non-displaced scaphoid fractures with a percutaneous screw has resulted in a shorter time to union (6-7 weeks versus 10-12 weeks) and faster return to work or sports.
Arora et al found the indirect cost reduction by a quicker return to work was shown to offset the direct costs of surgical intervention.The operatively treated group had a better mean DASH-score than the conservative group. Fracture union was seen in the screw fixation group at a mean of 43 days and in the cast immobilization group at a mean of 74 days.
Bond et al found in active military personnel there was faster healing but no difference in ultimate union rates or final grip strength or range of motion between percutanous screw fixation and non-operative groups. The average time to fracture union in the screw fixation group was seven weeks compared with twelve weeks in the cast immobilization group. There was no significant difference in the range of motion of the wrist or in grip strength at the two-year follow-up evaluation.
Arora R, Gschwentner M, Krappinger D, Lutz M, Blauth M, Gabl M
Arch Orthop Trauma Surg. 2007 Jan;127(1):39-46. PMID: 17004075 (Link to Abstract)
Arora, AOTS 2007
Bond CD, Shin AY, McBride MT, Dao KD
J Bone Joint Surg Am. 2001 Apr;83-A(4):483-8. PMID: 11315775 (Link to Abstract)
Bond, JBJS 2001
Average 3.0 of 24 Ratings
A 20-year-old skateboarder fell 6 months ago and has had radial-sided wrist pain since. His radiograph upon presentation to your office is shown in figure A. What is the most appropriate treatment at this time?
four corner fusion
long arm thumb spica cast
wrist arthroscopy to evaluate intercarpal ligaments
open reduction internal fixation with autologous bone graft
This patient has a scaphoid waist fracture nonunion. Several studies indicate that scaphoid nonunions left untreated have a determined course of collapse and progressive arthritis (scaphoid nonunion advanced collapse - SNAC). Per Markiewitz et al, the standard treatment of scaphoid nonunions is open reduction internal fixation with bone graft; non-operative treatment is not appropriate. Proximal row carpectomy and wrist fusion are salvage procedures reserved for patient that has an advanced scaphoid nonunion, collapse and wrist arthritis.
Markiewitz AD, Stern PJ.
Instr Course Lect. 2005;54:99-113. PMID: 15948438 (Link to Abstract)
HPI - Patient sustained a fracture of the scaphoid 10 years ago, not diagnosed, 5 years ago had a styloidectomy
How would you treat this patient?
Average 4.0 of 23 Ratings
A 27-year-old professional cowboy is thrown from a bull during the rodeo and lands on his hand. No deformity is identified and the hand is completely neurovascularly intact. Pain is present upon palpation of the anatomic snuffbox. A radiograph is provided in Figure A. The cowboy wants to return to competitive riding tomorrow. Which of the following is the best next step in management?
Cock-up wrist splint and immediate return to sport as tolerated by pain
Steroid injection of the snuffbox, taping of the wrist and return to sport
Percutaneous screw fixation of the nondisplaced fracture
Scapholunate ligament repair and percutaneous pin fixation
Tenderness with palpation of the anatomic snuffbox should raise suspicion of a scaphoid fracture. The radiograph does not show any findings, but scaphoid fractures are often not initially visualized on plain radiographs. Appropriate treatment for any patient with snuffbox tenderness entails cast immobilization with repeat radiographs at 2-3 weeks or advanced imaging with MRI to evaluate for a fracture that is not identified with plain radiographs.
The MRI that correlates with this patient's radiograph is provided in Illustration A and demonstrates a nondisplaced scaphoid fracture.
Gaebler et al performed an MRI study of 32 consecutive patients who were clinically suspicious for a scaphoid fracture, but no fracture could be indentified on wrist radiographs. The MRI was 100% sensitive and specific in diagnosing scaphoid fracture.
Treatment for this patient following the MRI would be debatable. Cast immobilization would be appropriate, but screw fixation may allow earlier return to sport. A percutaneous compression screw would be an appropriate technique for this scaphoid fracture.
Gaebler C, Kukla C, Breitenseher M, Trattnig S, Mittlboeck M, Vécsei V.
J Trauma. 1996 Jul;41(1):73-6. PMID: 8676426 (Link to Abstract)
Gaebler, JTACS 1996
A 35-year-old woman reports wrist pain after a fall onto an outstretched hand. On exam, she has focal tenderness over the wrist snuffbox. A radiograph and CT image are shown in Figures A and B. What is the proper treatment of her injury?
Rest, ice, elevation
Removable splint for comfort
Thumb spica cast
Open reduction, internal fixation
Vascularized bone grafting
The radiograph and CT scan show a displaced scaphoid waist fracture. Optimal treatment is ORIF with screw fixation.
The usual mechanism of injury to the scaphoid is axial load across a hyperextended wrist. Pain with resisted pronation, snuffbox tenderness and scaphoid tuberosity tenderness should all raise suspicion for a scaphoid fracture. AP and lateral X-rays, as well as PA view with the hand in ulnar deviation and an oblique 45 degree view with the hand in pronation can help to identify the fracture. Bone scan, CT and MRI can also be used to make the diagnosis if radiographs are indeterminate. ORIF is recommended for any fracture displaced more than 1mm, with a radiolunate angle greater than 15 degrees, with intrascaphoid angle greater than 35 degrees, associated with perilunate dislocation or with a proximal pole fracture. Optimal treatment is ORIF with screw fixation. For minimally displaced fractures, percutaneous or mini-open fixation allows minimal dissection and preservation of extrinsic ligaments.
Answer 1,2,3: Nonoperative management is not indicated in displaced scaphoid fractures
Answer 5: Vascularized bone grafting is reserved for cases of scaphoid nonunion.
HPI - 50 year old, right-handed female patient suffered from trauma one year ago. The patient sought medical advice and was told that she had a scaphoid fracture that required fixation. The patient refused surgery and a cast was applied for two months.
What additional imaging would you order in this patient?
HPI - Neglected trauma to right wrist 15 months ago.
How would you manage this patient?
HPI - 20years ago, slip down injury
--> intermittent pain during exercise
He has no problem ordinary life
What is the optimal treatment at this time?
HPI - history of injury right wrist joint 1 yr back. no treatment was taken
How would you treat this injury?