Lec: 4 Monteggia Fracture-Dislocation of the Ulna

Lec: 4 Monteggia fracture-dislocation of the ulna

It is fracture at any level of the ulna associated with dislocation of the radio humeral joint.

Classification; according to Bado’s classification the fracture is divided into 4 types;  Type I—anterior dislocation of the radial head and fracture of the ulna at any level with anterior angulation.  Type II—posterior or posterolateral dislocation of the radial head and fracture of the ulna with posterior angulation  Type III—lateral or anterolateral dislocation of the radial head with fracture of the ulna &lateral angulation.  Type IV—anterior dislocation of the radial head with fracture of the proximal third of the radius and fracture of the ulna at the same level.

Type I type II type III type IV Mechanism of injury; it is caused by either direct trauma or by fall on the hand with the elbow forced into hyperextension or the forearm into hyperpronation. X-ray; normally the line drawn along the shaft & the neck of the radius should pass through the capitulum on both anteroposterior & lateral view whatever the position of the elbow. In Monteggia #-dislocation this line passes anterior, posterior or lateral to the capitulum according to the type of the injury.

Treatment; the key to the treatment is to reduce the ulna & restore its length, and then the radial head will reduce spontaneously. In children the reduction can be achieved closed by traction & supination of the forearm, after reduction a cast is applied for 4 weeks. If closed reduction fails then open reduction &internal fixation with K-wire. In adult the fracture usually require open reduction & rigid internal fixation of the fracture, if this fails to reduce the radial head then open reduction of the radial head.

Complications; (1) Nerve injury this usually as a result of treatment from forceful manipulation or during surgical procedures (2) malunion of the ulnar # this lead to persistent dislocation of radial head (3) non union of the fractured ulna this need bone graft with plate &screws fixation.

Galeazzi fracture-dislocation of the radius

It is also called reverse Monteggia # or fracture of the necessity because it necessitate perfect reduction rigid fixation of the radius, it is fracture of the distal third of the radius with subluxation or dislocation of the distal radioulnar joint.

Mechanism of injury: fall on the hand with rotation force. Clinical features; there is prominence or tenderness of the distal end of the ulna (the dislocated ulnar head) the instability of the ulnar head can be demonstrated by ballottement test or piano-key sign (if we press the distal ulna it will ballot like the key of the piano).

X-ray; it will show transverse or short oblique # of the distal radius with angulation or overlap with subluxation or dislocation of the distal radioulnar joint Treatment; the dislocated ulnar head can’t be reduced unless the length of the radius is restored:  In children closed reduction followed by cast immobilization for 4 weeks.  In adults this need open reduction & internal fixation by plate & screws , after reduction of the radius there are 3 possibilities for the distal radioulnar joint: 1. The joint is reduced & stable then immobilization for few days then active movements started. 2. The joint is reduced but unstable, this require transverse radioulnar K-wire with the forearm in position of the stability (supination) supplemented with above elbow cast for 6 weeks. 3. The joint is irreducible this require open reduction of the joint followed by radioulnar K-wire & 6 weeks cast immobilization.

Fractures of the distal radius The injury of the distal radius include several types of distinct fractures, these are: (1)Colles’fracture (2) Smith’s fractures (3) Distal forearm fractures in children (4) Radial styloid fracture (5) Barton’s fracture (6) comminuted intraarticular fracture

Colles' fracture: It is a transverse # of the distal radius just above the wrist at the cortico-cancellous junction with dorsal displacement & radial tilt of distal fragment. It is the most common # in older people especially in the postmenopausal osteoporotic women. Mechanism of injury; it is caused by a fall on the hand with the wrist in extension. Clinical features: there is pain swelling with tenderness at the # site; there is characteristic deformity, the dinner-fork deformity, in which there is prominence on the back of the wrist &a depression in front.

Dinner-fork deformity X-ray: transverse # of distal radius just above the wrist, often with ulnar styloid #.

The distal fragment is impacted into radial tilt &backward tilt and sometime with comminution at the # site.

Dorsal & radial tilt Treatment;  If the # is undisplaced or minimally displaced then back slab for few days until swelling subside then complete cast for 4 weeks.  If the # displaced the reduction under anesthesia(haematoma block, or regional anesthesia), this is done by grasping the distal fragment then temporarily increasing the deformity by extending the distal fragment to disimpact the #, then applying traction in the length of the bone then we manipulate the distal fragment into flexion & ulnar deviation, then we apply back slab for few days after that a complete cast for 6 week, it is necessary to check the position by x-ray after 1 week for any redisplacement in the cast.  Comminuted, this may require percutaneous K-wire to hold the fragments; in severely comminuted # we can reduce the # by ligamentotaxis using cross-wrist external fixator.

Complications; 1- Compression of median nerve at the carpal tunnel this result from tight cast or from over flexion of the wrist if this happen then the cast should be removed & the wrist extended, if the compression persist then surgical decompression of the carpal tunnel, 2- Reflex sympathetic dystrophy; 3- Tear of triangular fibrocartilage complex. 4- Malunion: usually treatment is unnecessary; 5- Nonunion of ulnar styloid #. 6- Stiffness; 7- Extensor pollicis longus tendon may rupture few weeks later(6-8 weeks), clinically the patient cant extend the distal interphalangeal joint of the thumb, this can be treated by tendon transfer. Smith's fracture: It is a fracture of distal radius, like Colles', but with volar displacement of distal fragment (reversed Colles'); it is uncommon #. Mechanism of injury;: fall on back of wrist. Clinical features: pain, swelling, tenderness & deformed wrist.

Volar tilt Treatment: closed reduction by traction &extension of the wrist followed by 6weeks of cast immobilization.

Distal forearm fractures in children The distal radius & ulna are the commonest site of # in children, the fracture occur either through the growth plate (physis) or through the distal metaphysis of the radius or ulna. Mechanism of injury; it is caused by fall on outstretched hand, the distal fragment forced into dorsal angulation causing injury similar to Colles’ # it is called juvenile Colles’ #, sometime the distal fragment tilted on the volar side. Clinical features: painful, swollen &tender wrist; sometime, dinner-fork deformity. X-ray: physeal fractures: are usually Salter-Harris type І or П with dorsal &radial Shift and tilt of the epiphysis (juvenile Colles'). Metaphyseal fractures: either buckle (torus) #, angulated green stick # or completely displaced #.

Physeal fractures green stick # buckle (torus) # completely displaced #. Treatment;  For physeal # it is reduced by pressure over the distal fragment, then above elbow cast for 4 weeks.  For Metaphyseal #; (1) buckle # need only 2 weeks splinting (2) greenstick # need reduction by pressure over the fragment the above elbow cast with the wrist in flexion & the forearm in pronation, checking x-ray after 2 weeks.(3) completely displaced Metaphyseal # need reduction in the same way as Colles’ # then above elbow cast for 6 week, if reduction unstable or displacement occur in cast then percutaneous K-wires fixation.

Complications; (1) malunion, it is usually correct with bone remodeling as the child grows. (2) Premature fusion of the distal radial growth plate leading to discrepancy in the growth between radius & ulna with subsequent dislocation of the distal radioulnar joint.

Radial styloid fracture Mechanism of injury: it is caused by forced radial deviation of the wrist as in fall on hand. X-ray: transverse # line extending laterally from articular surface of the radius. Treatment: closed reduction &back slab with ulnar deviation; if this fails then ORIF using screw or K-wire.

Complication: osteoarthritis.

Barton's fracture-subluxation: It is either volar Barton’s in which the # line runs obliquely across the volar lip of the distal radius into the wrist joint, the distal fragment displaced anteriorly carrying the carpus with it. OR it is dorsal Barton’s in which the # line runs obliquely across the dorsal lip into the wrist joint, the distal fragment displaced posteriorly carrying the carpus with it.

Volar Barton’s Dorsal Barton’s Clinical features; pain, swelling, deformity & painful wrist movements.

Treatment;  Volar Barton’s, this is usually unstable after reduction, so it is better to use open reduction & internal fixation using small buttress plate.  Dorsal Barton’s can be reduced closed & usually it is stable after reduction, if displacement occurs then open reduction& internal fixation.

Buttress plate Carpal injuries These include: 1-ligament sprain; 2-fracture (usually of scaphoid); 3-dislocation of lunate; 4-injury of triangular fibrocartilage complex (TFCC) &distal radioulnar joint( DRUJ); 5-subluxation ( carpal instability). Scaphoid fracture: This account for >75% of all carpal #; it is rare in elderly & children. Mechanism of injury; this result from a fall on dorsiflexed hand. Pathological anatomy; the main blood supply to the scaphoid enter the bone from the distal part of the bone & it is diminish proximally, there for the incidence of avascular necrosis is 1% for distal 1/3 #, 20% for middle 1/3 # & 40% for proximal 1/3 #.

Clinical features: fullness &tenderness in the anatomical snuffbox. Proximal pressure along the axis of the thumb is painful. Also there is weakness of the grip & pain on dorsiflexion of the wrist. X-ray: often a recent # can be shown only in oblique view while the AP & lateral views may look normal; two weeks later, can be seen in AP &lateral views because the inflammatory process of the healing will lead to bone resorption at # site which appears as transverse # line through the waist of the bone (the narrowest part of the scaphoid) this is the most common site of the #. Less often, is proximal pole #, distal pole # or scaphoid tubercle #.

Treatment: Undisplaced #; needs 6weeks cast (from below elbow to metacarpal necks &including the proximal thumb phalanx in( 'glass-holding' position)then remove the cast, at that stage one of two pictures may emerge: 1- If there is no tenderness &x-ray shows healing the wrist is left free 2-if scaphoid still tender &x-ray show no fracture union, then another 6weeks in cast, at that time either the # is united; or there is delayed union (cavitations at # line on x- ray)this needs bone graft & internal fixation using screw. Displaced #needs ORIF using Herbert compression screw &/or K-wires.

'glass-holding' position avascular necrosis Complications: 1- Avascular necrosis: of the proximal fragment (because its blood supply comes distal to the #; it appears dense on x-ray) if the carpus become painful then excision of dead fragment or excision of scaphoid & fusion of the proximal & distal rows of the carpus. 2- Non-union→ bone graft. 3- Osteoarthritis. Note: in children the fracture scaphoid is less common than adult because the thick cartilage cover, the displacement is rare & the distal pole rather than waist is the common site of the #.

Lunate &perilunate dislocations: Mechanism of injury: fall on dorsiflexed hand may tear the carpal ligaments; usually the lunate remains in its position &the rest of the carpus dislocated backward (perilunate dislocation) sometime taking part of scaphoid with them trans-scaphoid- perilunate dislocation) often the hand return to normal position levering the lunate anteriorly out of its position (lunate dislocation).

Perilunate dislocation lunate dislocation Clinical feature: there is pain, swelling, tenderness& there may be signs of median nerve compression by the dislocated lunate. X-ray: on AP view: there is disturbance of the parallel carpal arcs, the dislocated lunate looks triangular (not quadrilateral).on Lateral view: either the lunate remains in line with radius (perilunate dislocation) or out of radius (lunate dislocation).

Normal carpal alignment triangular shape dislocated lunate Treatment: by closed reduction followed by 6weeks splinte, if closed reduction failed then ORIF using K-wires with ligament repair followed by 6weeks splint. Complication: median nerve compression & avascular necrosis of the lunate.

Avascular necrosis of the lunate

Scapholunate dissociation: It is due to scapholunate ligament tear, so the scaphoid no more than connected to the lunate, the scaphoid will rotate & flexed Clinical features; it cause persistent wrist pain & tenderness over the dorsum of the wrist after wrist sprain X-ray: shows a large gap between scaphoid &lunate (Terry Thomas sign) with the scaphoid flexed & shorten (cortical ring sign).

Terry Thomas sign Treatment: early, ligament repair with K-wires fixation; later lesions require arthrodesis.