Download Katie Lott EBP Scaphoid Fracture Background on injury The wrist is

Katie Lott
EBP Scaphoid Fracture
Background on injury
The wrist is made up of the radius, ulna, and two rows of carpel bones: distal and
proximal. The distal row is made up of the trapezium, trapezoid, capitate, and hamate. The
proximal row of carpel bones are the scaphoid, lunate, triquetrum, and pisiform. The scaphoid
is the largest carpel bone and has been also known as the navicular because of its boat like
shape. The scaphoid is named by its regions which are the proximal pole, distal pole, and the
waist. 1 The dorsal and palmar surfaces are non-articular with multiple arterial foramina. 75%
of blood supply branches off of the radial artery with a single forman reaching the proximal
pole of the scaphoid.5
The scaphoid bone consists of 70% of all carpel fractures because of its function as a
bony block to stop the wrist from going into extension.14 The mechanism of injury of a scaphoid
fracture is a fall on outstretched hand, which is a compression of the radial side of the palm.
Falling backwards with the hand directly anteriorly, is a common way to force extreme
hyperextention.5 Scaphoid fracture findings consist of swelling, tenderness, and crepitus over
the anitomical snuffbox area. Pain and decreased active range of motion during dorsiflexion
and radial deviation may be current. Also, pain during extension, radial deviation, and possibly
flexion during passive range of motion. Range of motion may be decreased from the norm of 70
degrees of extension along with grip weakness.14
Special tests for a scaphoid fracture include the scaphoid compression test, scaphoid
tubercle tenderness, and snuffbox tenderness. Accuracy of the clinical tests shows specificity
and sensitivity results. Sensitivity means that a negative finding rules the pathology out.
Specificity means that a positive finding will rule the pathology in.14 Snuffbox tenderness is 40%
specific and 90% sensitive. Effusion over the snuffbox is 91% specific and 50% sensitive.
Tenderness over scaphoid tubercle 57% specific and 87% sensitive. Scaphoid compression test
is 92% specific and 94% sensitive. Combined is 74% specific and 100% sensitive.5
Differential Diagnosis
There are many structures in the wrist that may be the cause of wrist pain. Because the
scaphoid is such an odd shaped bone, it is often missed on x-rays which may lead to missed
diagnoses. Differential diagnoses of wrist pain on the radial side are scapholunate sprain,
radial styloid fracture, and trapezium fracture.
A similar mechanism of injury, falling on outstretched hand, is a common way to injure
the scapholunate ligament. The scapholunate ligament is the ligament between the scaphoid
and lunate. Extension and ulnar deviation can result in stretching the scapholunate ligament,
which if severe enough can lead to subluxation of the scaphoid. This injury may cause chronic
instability if not treated correctly.8 A radiograph or MRI must be taken to be sure this injury is
not a scaphoid fracture.
Radial styloid fracture presents very similar to a scaphoid fracture because of its location
and mechanism of injury. The radial styloid is just proximal to the scaphoid bone and is most
commonly injured by radial deviation with much force. Tenderness over the radius verses
snuffbox tenderness will differentiate between the two fractures. 6 A radiograph or MRI can
also be taken to decide whether there is a fracture and where the fracture is at.
Trapezium fractures are one of the more rare carpal bones that are fractured. About
1%-5% of all carpal injuries are to the trapezium bone. Tenderness over the trapezium verses
the snuffbox tenderness like a radial styloid fracture will differentiate between the two
fractures. A radiograph or MRI can be used to rule in or out a trapezium fracture. 7
Diagnostic Imaging
There are many different views needed when x-raying for a scaphoid fracture:
posterior-anteroir, lateral, oblique (semipronated and semisupinated), posterior-anterior with
ulnar deviation, posterior-anterior with radial deviation, and posterior-anterior with clinched
fist. These combination of X-ray views should be used as standard care for a scaphoid fracture.
These angles increase the sensitivity and specificity.2
There are many different types of diagnostic imaging for a scaphoid fracture:
radiograph, CT scan, MRI, and bone scan. Each of these different diagnostic imaging has their
positives and negatives. Rhemrev's article states his findings of the sensitivity and specificity
for each diagnostic imaging. When talking about the basic and cheapest diagnostic imaging, the
radiograph, he states that it will catch about 70% of scaphoid fractures. CT scans have an
average sensitivity of 93% and an average specificity of about 99%. MRI has an average of 80%
sensitivity and an average of 100% specificity. Bone scans have an average sensitivity of 100%
and have an average specificity of 90%. 12
Surgical Intervention
Operative treatment has improved over the years becoming minimally invasive surgical
technique of displaced scaphoid fractures and is becoming more common. This is being
managed by a percutaneous screw fixation. Operation done on the proximal pole can be
approached by the dorsal or volar side where as the distal and waist fractures are approached
from the volar side because of exposure to blood supply. If surgery is performed the long
conservative immobilization of 8-12 weeks can be avoided. 12
Fernandez states an internal fixation surgical method using a radial wedge graft. The
main purpose of this procedure it to restore union of the scaphoid and decrease the instability.
The graft is used from an osteotomy of the radial styloid and the wedge shaped area of the
scaphoid is filled with the graft. The procedure findings show that it did successfully achieve
union of the scaphoid, even when there was avascular necrosis present. This also has a 100%
union rate between the 40 operative cases treated. 4
A more recent look at non-union internal fixation of displaced scaphoid fractures is the
screw fixation, which is the regular method for treatment lately. A good benefit of using this
method of surgical fixation is that the screw can be recessed below the articular cartilage that
can be accessed both dorsal and palmar. The screw is placed in the middle of the scaphoid to
allow the displaced pieces to come together and heal. An important achievement is about 95%
of screw fixation for acute scaphoid fractures were successful. Bone grafting has been found to
be successful as well. Bone grafts are taken from the iliac crest and inserted into the scaphoid
using the screw fixation, which 94% were successful union rates followed by 6 weeks of
immobilization. 9
Potential medications post surgery may include: Tylenol, narcotic analgesics, and
antiemetic. NSAIDS are not recommended because it is an anti-inflammatory. Physicians want
the bone to have that inflammatory phase. Tylenol is over the counter and helps decrease
pain, yet is not an NSAID. Narcotic Analgesics use opiates to decrease pain and impulses at the
brain. Antiemetics are used to treat nausea and vomiting post surgery.
11
Rehabilitation
Conservative treatment for a scaphoid fracture if it is non-displaced or minimally
displaced is eight to twelve weeks in a cast. Depending on the doctors point of view and
knowledge will determine if the cast is a thumb spica and whether it is a short cast or a cast
that is placed above the elbow joint. Successful healing through conservative treatment is 88%95%. The negative side to this treatment is that doctor visits are more constant because the
doctors are checking the healing progress and fracture alignment frequently.9 While the
fracture is healing and immobilized no modalities are needed because of contraindications.
Once the patient is out of the cast, heating modalities can be used for 15-30 minutes to
increase blood flow and collagen extensibility to regain lost range of motion. 10
There are two sets of phases when it comes to scaphoid fractures. The bone healing
phases, and post operative rehabilitation phases. Bone healing during the 3 phases: Bone
inflammation- When a bone is fractured it is not just the bone that is damaged it is the vessels,
matrix, surrounding muscles, and nerves. Immediately following a fracture the inflammatory
process is elicited. Inflammation helps immobilize the fracture in two ways, pain and swelling.13
Bone repair- During this phase a development of a reparative callus in tissue surrounding the
fracture site eventually turning into bone. The role of the callus is to enhance the mechanical
stability of the site by supporting the fracture. Damaged surrounding tissue, periosteum , and
marrow contribute to tissue that is being reabsorbed near the fracture site. As repair
progresses the pH gradually becomes neutral and then slightly alkaline.13 Remodeling- The
remodeling phase of fracture healing begins with replacement of woven bone by lamellar bone
and the resorption of the callus.13
Post surgery inflammation phase leukocytes migrate and phagocytosis occurs during the
first 48 to 72 hours. Primary goals during the inflammation phase is while the wrist is
immobilized is to decrease pain (0/10), reduce inflammation, and control edema formation.
During the first 24 to 48 hours ice may be applied to the area to assist with primary goals and to
prevent secondary injury.10 The patient may try contracting the muscles that are being
immobilized during this time. After six weeks of being immobilized post operative by a cast,
we can move into the second phase of rehab knowing that the bone is healed at this time. 15
The primary goal for the repair phase is to increase the patients range of motion, pain
free, to what their full range of motion was pre-surgery. During the repair phase collagen is
being laid down and blood flow is increased which promotes healing. The repair phase may
lead to the formation of scar tissue. Cross friction massage can help break up adhesions and
scar tissue especially near the incision site. Heating modalities that are not contraindicated can
start to be used to increase blood flow to the area and increase collagen extensibility 15- 30
minutes prior to exercises.10 Flexibility should include passive, active assisted, and active
stretching of the flexors, extensors, and radial and ulnar deviators. Extension loss from a
scaphoid injury can be increase by an extension progression starting with the wall then moving
to a table then to floor push-ups. Wrist injuries react well to joint mobilizations which can help
increase range of motion. Anterior and posterior glides will increase wrist extension and wrist
flexion. Radial and ulnar glides will increase the wrists ulnar and radial deviation.11
The primary goal during the maturation phase is to strengthen muscles surrounding the
wrist joint, increase grip strength, and return to activity by week 14. Wolff's law states that
bone will adapt to any stresses that are put on it by changing its size and structure. During the
remodeling phase similar to bone, collagen will realign due to its function and strain that is put
on it.11 Strength exercises consist of resistive movements of wrist rolls, flexion, extension, ulnar
and radial deviation, pronation, and supination. Grips strength is very important to gain back in
the hand. Grips exercises and progression consist of squeezing putty, foam, rubber, and a
power web. Grip strength can be measured bilaterally by a dynamometer. A big part of
regaining function of the hand and wrist is to accomplish every day activities like buttoning and
unbuttoning buttons, picking up small objects like jelly beans, writing, and tying shoes.11
Heating modalities can be used to bring blood flow to tissues before exercises are performed.
Once exercises are performed ice may be applied to the area for 20 minutes to relieve pain and
irritation during the exercises.10 Patient or athlete may return to activity once the wrist's
strength and grip strength are equal bilaterally and there is no pain with full range of motion. A
splint or brace may be used as needed to protect the wrist from further injury.11
Conclusion
Although it may be difficult to see a scaphoid fracture on a radiograph the physician
may immobilize the wrist for two weeks and then contain another radiograph. Precaution is
key due to avascular necrosis of the scaphoid bone, if steps are not taken properly to heal the
injury. A scaphoid fracture takes many weeks to heal whether treated conservatively or an
operative route is taken. This is the reason why the rehabilitation part of injury healing is
necessary to understand and follow.
References
1- Berger R. The Anatomy and Basic Biomechanics of the Wrist Joint. Journal of Hand Therapy.
1996; 84-92.
2- Chechik O, Rosenblatt Y. Management of Clinically Suspected Scaphoid Fractures: A Survey of
Current Practice in Israel. 2009; 11: 225-227.
3- Doblare M, Garcia JM, Gomez MJ. Modeling Bone Tissue Fracture and Healing. Engineering
Fracture Mechanics. 2004; 71: 1809-1840.
4-Fernandez D. A Technique for Anterior Wedge-Shaped Grafts for Scaphoid Nonunions with
Carpal Instability. The Journal of Hand Surgery. 1984; 733-734.
5- Focus on Scaphoid Fractures. The Journal of Bone and Joint Surgery. 2011; 1-6.
6- Freeland A, Jabaley M, Hughes J. Radial Styloid Fractures. Stable fixation of the Hand and
Wrist. 1986; 123-126.
7- Horch R. A New Method For Treating Isolated Fractures of the Os Trapezium. Archives of
Orthopedic and Trauma Surgery. 1998; 117(3): 180-182.
8- Jones W. Beware of the Sprained Wrist. The Journal of Bone and Joint Surgery. 1988; 70:
293-295.
9- Kawamura K, Chung K. Treatment of Scaphoid Fractures and Nonunions. Journal of Hand
Surgery. 2008; 33: 988-996.
10- Knight K, Draper D. Therapeutic Modalities. Philadelphia, PA: Lippincott Williams &Wilkins,
Wolters Kluer Business; 2013: 75-130.
11- Prentice WE, Principles of Athletic Training. New York, NY: McGraw-Hill Companies; 2014:
269-277, 745-750.
12- Rhemrev S, Ootes D, Beeres F, Meylaerts S, Schipper I. Current Methods of Diagnosis and
Treatment of Scaphoid Fractures. International Journal of Emergency Medicine. 2011; 27.
13- Sfeir C, Ho L, Doll BA, Azari K, Hollinger JO. Fracture Repair. 22-37.
14- Starkey C. Athletic Training and Sports Medicine. Burlington, MA: American Academy of
Orthopaedic Surgeons; 2013: 436-440.
15- Starky C, Brown SD, Ryan J. Examination of Orthopedic and Athletic Injuries. Philadelphia,
PA: F.A. Davis Company; 2010: 796-797.