Abdulaziz Al-Ahaideb PGY2 March 23/2001 Scaphoid Fractures Abdulaziz Al-Ahaideb PGY2 March 23/2001

Scaphoid Fractures Introduction Anatomy Biomechanics History Clinical examination Radiographic evaluation DDx Classification Treatment Complications

Scaphoid fractures Introduction Scaphoid fractures constitute 60-70 % of all carpal bone fractures Second only to the distal radius in frequency Due to the importance of scaphoid in wrist mechanics and because of the frequency of the fracture in young adult male, it has an economic as well as physical significance Uncommon in children because the physis of distal radius fails first Has economic as well as physical significance due to the importance of scaphoid in wrist mechanics and because of the frequency of the fracture in young adult male. Uncommon in children because the physis of distal radius fails first.

Anatomy Also called Navicular An irregular shaped bone ,more resembling a twisted peanut than the boat for which it is named Scaphoid represents floor of the anatomic snuff box

Anatomy Articular cartilage covers 80 % of the scaphoid surface - only narrow area of its neck, & even smaller distal portion, are accessible to blood vessels Distally, it articulates with the trapezium and trapezoid in a gliding motion, The articulation with the trapezium forms a base for independent movement of the thumb On the ulnar side, it articulates distally with the capitate, and proximally with the lunate in a rotary motion Proximally, its large, biconvex surface allows articulation with the radius

Anatomy -ligaments

Anatomy Blood Supply Major blood supply comes from the scaphoid branches of the radial artery entering the dorsal ridge at or just distal to waist area and supplying 70-80 % of the bone including the entire proximal pole - in a retrograde fashion Second group of vessels, arise from palmar & superficial palmar branches of radial artery & enter the distal tubercle, it perfuses distal 20-30 % of bone, including tuberosity

Blood Supply There are no anastomoses between the dorsal and palmar vessels Vessels enter thru dorsal ridge in 79 %, distal to waist in 14 %, & proximal to waist in 7 % Fractures across scaphoid may destroy blood supply to its proximal part

Biomechanics Mechanically scaphoid links the proximal and distal rows Scaphoid spans both carpal rows and therefore has less mobility than other carpal bones Scaphoid carries the compressive loads from the hand across the wrist to the distal forearm

Biomechanics Scaphoid flexes with wrist flexion & extends with wrist extension It also flexes during radial deviation & extends during ulnar deviation These factors make immobilization of scaphoid fractures difficult especially when there is displacement - as wrist rotates from neutral to ulnar deviation, proximal row dorsiflexes & x-ray profile of the scaphoid appears longer; - in radial deviation, proximal carpal row volar flexes & scaphoid appears foreshortened; - hence, ulnar deviation AP is necessary for visualization of scaphoid;

Biomechanics Scaphoid is a principal bony block to dorsiflexion of hand & wrist , and is susceptible to frx during fall on outstretched hand With scaphoid fx, distal scaphoid tends to flex, & proximal scaphoid extends with the proximal carpal row ,, because of this, angulation occurs at fx site, which gradually leads to a humpback deformity

Mechanism of injury Two different mechanisms Compression injury : usually results in non displaced fx Hyperextension bending injury : usually results in displaced fx Compression injury results from a more longitudinal load or impaction of the wrist leads to intraction of the scaphoid without displacement Hyperextension bending injury :tensile stresses generated palmarly when excessive hyperextension is applied to the wrist and when the excessive tensile forces exceed bone strength produce a fx thru the scaphoid that commonly results in fx displacement

Diagnosis A strong index of suspicion is the key to early diagnosis The diagnosis should be based on : History Clinical examination Radiographic evaluation

History Occurs after a fall on an outstretched hand, athletic injury, or MVA Usually happens in young adult men Pain at the radial side of the wrist Associated injuries

Clinical Examination Should demonstrate tenderness in the anatomic snuff box Tenderness to palpation over scaphoid tuberosity and/or proximal pole just distal to Lister's tubercle Tenderness with axial compression of thumb toward the snuff box Tenderness as patient supinates forearm against resistance limitation of wrist motion – but not dramatically

Clinical Examination Radial & ulnar deviation results in pain on radial side of wrist Forced dorsiflexion usually elicits significant tenderness There is usually pain at extremes of motion Limitation of wrist motion – but not dramatically Swelling – usually not present Ecchymosis or swelling is not present except in fracture-dislocation

Radiographic Evaluation The best method for determining the presence of a fracture Many different views have been recommended The useful initial views are : PA, lateral, scaphoid view ( PA with ulnar deviation ) Scaphoid view is - consider obtaining a CT scan of the scaphoid on the day of injury, if is essential to know the diagnosis (such as w/ a surgeon or an athlete)

Radiographic Evaluation Motion views of the wrist ( flexion-extension-radial & ulnar deviation ) may demonstrate fracture displacement If a diagnosis still can’t be confirmed with confidence on routine films, further oblique views can be taken If certainty still exists after all these maneuvers , the patient should be placed in a cast for 2 to 4 weeks and the clinical & radiographic evaluation repeated The same x-rays should be repeated if the initial films were negative because resorption may assist identification by widening the fracture line,,,, it is imperative for the orthopedist to make the Dx at this time because a delay in the Dx increases the incidence of the scaphoid nonunion -- Terry and Ramin have called attention to a small radiolucent area normally present next to the scaphoid in anteroposterior view radiographs,which they named the navicular fat stripe, a fracture on the radial side of the wrist can either displace or obliterate this line. A preserved fat stripe is a strong indication that a fracture has not occurred. This sign is valuable only in fresh fracture..

Radiographic Evaluation If the second radiographic examination is still equivocal , a technetium bone scan, polytomography, CT or MRI of the wrist is recommended The bone scan is the most sensitive but the least specific of these modalities, thus if the bone scan is negative , a scaphoid fx is ruled out Bone radionuclide imaging was performed 2-3 hours after administration of technetium-99m methylene diphosphonate, 4 days after injury - false-positive rate: 6-16% - false-negative rate: 0%;

Radiographic Evaluation If the bone scan is positive, more specific studies ( e.g. polytomography, CT or MRI ) can be helpful polytomography, or CT ………..axial views Intrascaphoid angle Normal is 32

DDx It is the same DDx of radial sided wrist pain Lunate dislocation or fx Sapholunate instability Radial styloid fx Trapezium fx Rupture of FCR tendon ECRB or ECRL avulsion

Classifications of scaphoid fx Location of the fracture : 5 different fracture sites : Proximal third ( proximal pole ) .. 25% Middle third ( waist )… most common 65% Distal third …..10% Tuberosity Distal articular surface ( osteochondral fx )

Classifications of scaphoid fx Direction of the fracture : Horizontal Oblique , Transverse , and Vertical Oblique (Russe’s Classification ) Vertical oblique fractures are considered unstable

Classifications of scaphoid fx Time since injury : Acute fracture - less than 3 weeks old Delayed union - 4 to 6 months old Nonunion - more than 6 months old Time since injury : these are - of course – arbitrary definitions and no one can say with certainty when a delayed union begins or ends Nonunion - more than 6 months old ---- however many clinicians diagnose these fractures as nonunions regardless of the time period if bone resorption ,cyst formation , or sclerosis is present.

Classifications of scaphoid fx Amount of fracture displacement ( stability ) : Undisplaced ---- stable Displaced ---- unstable Amount of fracture displacement this is the most important classification and the practical one. As mentioned earlier undisplaced fx results from an impaction injury while the displaced fx results from hyperextension bending injury

The unstable fracture (displaced) is defined as : - presence of a fracture gap > 1 mm on any radiographic projection - scapholunate angle > 60 - radiolunate angle > 15 - or intrascaphoid angle > 20 intrascaphoid angle > 35 (Normal angle is 32)

Herbert’s Classification

Prognosis Negative prognostic factors are : late diagnosis proximal location displacement angulation obliquity of the fracture line smoking carpal instability

Treatment Is determined by: Location Degree of displacement Fresh vs old fracture

Treatment Undisplaced ( stable) fracture : Nonoperative ( cast immobilization )--- there have been three main areas of disagreement in non-operative treatment of acute non displaced fractures of scaphoid : 1- the position of the wrist in the cast 2- the need to include joints other than the wrist in the cast 3- the duration of the immobilization It is in this area that most of the controversy regarding scaphoid fx still exists,,this is due to 1.s fx isn’t always isolated fx 2. The definition of successful result isn’t well known ( one def, is adequate motion and no significant pain ….a better def. Is treatment results in a radiologiclly proven healed scaphoid with normal carpal alignment Almost every position of the wrist have been advocated ,including flexion,extension,radial deviation,ulnar deviation,neutral and various combinations re: casting -- most surgeons leave the IP joint free

Treatment Many types of cast immobilization have been described in the literature No evidence exists to prove greater efficacy for one casting position over another. Although above elbow casts may have a slightly shorter time to union, the final rate of union is the same for below or above elbow casts. The key factor in treatment of scaphoid fractures is the duration of immobilization rather than the specific position

The current recommendation is to use a short arm thumb spica with the thumb interphalangeal joint free. The wrist is placed in radial deviation Long arm cast is recommended for nondisplaced proximal pole fx

Time to healing by location : Distal third fx heals in 6-8 weeks Consider changing the cast every 10-14 days for the first 6 weeks so that it remains firm around forearm muscles and the wrist Time to healing by location : Distal third fx heals in 6-8 weeks Middle third fx 8-12 weeks Proximal third fx 12-24 weeks A 95 % union rate can be expected with this management times to union increasing for more proximal fractures - immobilization for 16 weeks to 6 months is sometimes required - undisplaced fractures unite in 8 to 12 weeks - - many surgeons will cast for an additional 4-6 weeks once trabeculation is seen crossing the frx site (on radiographs), since the same frx seen on CT scanning may demonstrate a persistent frx gap; - if x-rays fail to clearly demonstrate trabeculae crossing site of frx, CT scan along axis of carpal scaphoid is performed; - this allows assessment of possible scaphoid nonunion

Removal of the cast should not occur until union has been documented on CT or tomography Prognosis is excellent in undisplaced, stable fractures if diagnosed and immobilized early (95 % with x-ray evidence of beginning consolidation at 6 weeks )

Initial delay in treatment does not preclude casting If treatment is instituted within four weeks no effect on healing time or rate of union has been shown Delay beyond six months invariably requires operative treatment The difficulty lies in fractures between six weeks and six months. If no evidence of bony resorption exists, casting may result in union. If bony resorption or displacement greater than 1 mm exists, operative reduction and bone grafting will be needed

Treatment Cast immobilization and electrical stimulation : the M/A isn’t fully understood It is worthwhile to try electrical stimulation (esp.when there is nonunion ), though there is a lack of reliable double-blind study which compares between series of patients treated with immobilization alone and those treated with immobilization and ES, electrical stimulation……in the absence of controlled studies showing the efficacy of electrical stimulation,,we prefer the bone grafting as the next step after failure of cast treatment

If the patient will not tolerate prolonged cast immobilization (e. g If the patient will not tolerate prolonged cast immobilization (e.g. professional athletes and manual laborers ) early internal fixation should be performed Internal fixation for fresh nondisplaced proximal pole fractures has been recommended by some authors

Treatment Displaced fractures : Primary internal fixation is treatment of choice for unstable scaphoid frxs Fractures treated by primary internal fixation, average time for return to work is 3.7 weeks with union rate 97 % this compares very favorably with conservative treatment

Indications of Surgery in Scaphoid fractures Displaced acute fracture Delayed union or nonunion when bone grafting is insufficient to provide adequate internal fixation S.Fx associated with a perilunate fx or dislocation Ligamentous injury Non displaced fx of proximal pole Non displaced fx if the pt will not tolerate prolonged cast immobilization (e.g. professional athletes and manual laborers )

The choice of the surgical procedure will vary with the surgeon’s preference and experience, the type of the fracture, the patient’s age, and the presence of periscaphoid arthrosis The most important aspect of the treatment is meticulous technique and not the device or equipment selected Reduction of the fracture should be anatomic

ORIF of scaphoid fractures can be done by many ways : K-wires ( easy insertion ) Herbert screws ( headless, multipitched,difficult insertion ) AO screws Herbert-whipple screw Ender’s plate Staples

The surgical approaches : Volar approach -- is most of the time the preferred approach to limit the injury to the blood supply of the scaphoid Dorsal approach – will be used to address the fractures of the proximal approach Volar approach : between FCR tendon and the radial artery Dorsal approach:through the third dorsal compartment,,the incision is centered over Lister’s tubercle,,retracting EPL

Volar approach: between FCR and the radial artery

Treatment of middle third fxs They are the commonest (65%) If fresh stable: short-arm thumb spica cast If fresh undisplaced but potentially unstable (e.g. vertical oblique) and stable fx older than 3 wks : long-arm thumb spica cast If fresh displaced : ORIF (k-wires or screws)

Proximal Pole Fractures challenging Often difficult to heal Prolonged immobilization- snug , well molded long arm cast- (sometimes exceeds 9 mos) has been necessary with conventional casting Early incorporation of PES has been recommended

Proximal Pole Fractures There is increasing favor to proceed to ORIF A dorsal approach allow s direct visualization of the fracture If it is a fresh fx, can be fixed by 2-3 k-wires The k-wires are extracted in a retrograde fashion in 6-8 weeks Alternatively ,one may use a Herbert screw which may be inserted retrograde while the fragment is stabilized in a k-wire

Proximal Pole Fractures Determination of bony union is not easy Tomography or CT is needed Multiple follow up films should be obtained for several months after the assumed healing

Distal Pole Fractures These are often avulsion injuries of the tuberosity and can be expected to heal promptly with cast treatment Fresh and undisplaced should heal in 4-8 wks in a cast Displaced fx needs ORIF

After treatment care After achieving a rigid fixation , there is a big controversy about the need for immobilization Some authors recommend a long arm cast after k-wire or compression screw fixation for 2-3 weeks New literature is in favor of early mobilization

Complications of Scaphoid Fx Delayed union or Nonunion Malunion (Humpback deformity) SLAC wrist Osteonecrosis

Nonunion The incidence of scaphoid nonunion for undisplaced fx is 5-10% The incidence increases up to 90% in displaced proximal pole fxs Risk factors : Proximal pole fx Displacement Late diagnosis Inadequate immobilization Associated ligamentous injuries

Nonunion Failure to heal after 6 months establishes the Dx of nonunion Recent studies indicated that virtually that all unstable nonunions lead to carpal collapse and posttraumatic arthritis,, for this reason treatment is recommended for all scaphoid nonunions even if asymptomatic Thin cut CT scan show more details than conventional tomograms Sagittal views are helpful in determining the degree of carpal collapse and humpback deformity

Treatment of Nonunion Bone grafting : 2 types of bone grafting are indicated for tx of nonunion: Russe bone graft (inlay): used for stable nonunions .the initial procedure used a single corticocancellous strut across the fracture line;a later modification involved two corticocancellous struts inserted into the scaphoid excavation with their cancellous sides facing each other,the remainder of the cavity is filled with cancellous chips. Usually k-wires are added to secure the construct. Bone grafting is the oldest method for nonunion and delayed union treatment. The original Matti technique as described in 1937 consisted of excavation of the proximal and distal fragments through adorsal approach and placement of a cancellous strut within these two cavities to act as an internal fixationdevice as well as a nidus for osteogenesis In 1960,Russe described a volar approach .

Inlay graft

Con’t Russe bone graft The time to union with this procedure is relatively long ,generally requiring cast immobilization for 6-4 months Healing rates of 85-90 % have been reported Satisfactory relief of symptoms has been reported ; 78 % of painful wrist became free of symptoms and 88 % of patients were satisfied with the results

Con’t Bone Grafting Fernandez bone graft (interpositional graft): angulated nonunions with a dorsal humpback deformity require interpositional grafting. Fernandez has described the use of a trapezoidal iliac graft to correct the angulation and carpal collapse pattern.Fixation is achieved with screws or k-wires In both types of bone grafting ,a volar approach is used, and care must be taken to preserve the vascularity of the fragments

Interpositional graft

Treatment of Nonunion B) Electrical stimulation: Pulsed Electromagnetic Field ( PEMF ) stimulation has been investigated as a noninvasive treatment for scaphoid nonunion.Although controversial, there appears to be some benefit (shorter healing time)when electric stimulation is combined with bone grafting procedures

Treatment of Nonunion C) Proximal pole excision: when a small proximal fragment is not amenable to bone grafting ,proximal pole excision and fascial hemiarthroplasty are recommended

Treatment of Nonunion D) Salvage procedures : Are indicated when nonunion has lead to carpal collapse and secondary degenerative changes Proximal row carpectomy,intercarpal arthrodesis, or radiocarpal arthrodesis is recommended in patients with chronic wrist pain and stiffness Radial styloidectomy and scaphoid interposition arthroplasty may be combined with other procedures or performed independently in the younger patient with less severe symptoms Silicone implants have been used in the past but are now avoided because of silicone synovitis

Malunion Malunion of the scaphoid may occur when a displaced or angulated fracture is allowed to heal without anatomic reduction In most of cases , there is a dorsal angulation resulting in a fixed humpback deformity DISI pattern ensues ,resulting in pain ,loss of motion, and decreased grip strength Treatment in a young patient includes osteotomy,volar wedge bone graft,and internal fixation Once degenerative arthritis has begun ,treatment is limited to a salvage procedure such as proximal row carpectomy,intercarpal arthrodesis,or complete wrist fusion

Osteonecrosis

SLAC scapholunate advanced collapse (SLAC) refers to a specific pattern of osteoarthritis and subluxation which results from untreated chronic scapholunate dissociation or from chronic scaphoid nonunion

Case # 1 J.D. 24 y.o male . Fell on his out stretched hand while snowboarding on March 7/2000 C/0 pain Lt wrist , no other injuries. O/E : Lt wrist tenderness, neurovascular intact X-rays :

ER x-ray Fracture scaphoid and perilunate dislocation

Lateral view

Post -reduction

ORIF March7/2000 Volar approach, we placed 2 k-wires through the proximal and distal fracture fragments of the scaphoid to use them as joysticks , we were then able to reduce the scaphoid.we then placed a guide wire for the herbert screw from distal to proximal perpendicular o the transfer fracture. We then used a no. 18 mm Herbert screw to affix the scphoid fracture. To aid in the reduction we placed percutaneously a k-wire through the radial aspect of the scaphoid to help maintain the reduction We also placed a k-wire from the triquterum to the lunate to hold the carpal bones stable

May1/2000 7 wks post ORIF Still the fracture line is visible

May1/2000 7 wks post ORIF So the pins are out May 1/2000

May 29/2000 11 wks

May 29/2000 ?union ??AVN