Pediatric Fractures of the Forearm, Wrist and Hand

Pediatric Fractures of the Forearm, Wrist and Hand د. رائد كساب

Pediatric Forearm Fractures- Radial and Ulnar Shafts • Approximately 4% of children’s fractures • Middle and proximal radius more protected by musculature than distal • Ulna subcutaneous and susceptible to trauma when raised for self protection • Most fractures are from fall on an outstretched arm

EPIDEMIOLOGY • These injuries are very common: They make up 40% of all pediatric fractures (only 4% are diaphyseal fractures), with a 3/1 male predominance in distal radius fractures. • 80% occur in children >5 years of age. • The peak incidence corresponds to the peak velocity of growth when the bone is weakest owing to a dissociation between bone growth and mineralization. • 15% have ipsilateral supracondylar fracture. • 1% have neurologic injury, most commonly median nerve. • Of pediatric forearm fractures, 60% occur in the distal metaphyses of the radius or ulna, 20% in the shaft, 14% in the distal physis, and <4% in the proximal third

Forearm Developmental Anatomy • Primary ossification centers at 8 weeks gestation in both radius and ulna • Distal physes provide most of longitudinal growth • Distal epiphyses of radius appears radiographically at age 1, of distal ulna at age 5 • Proximal and middle radius connected to ulna by intraosseous membrane

Forearm Developmental Anatomy • The radial and ulnar shafts ossify during the eighth week of gestation. • The distal radial epiphysis appears at age 1 year (often from two centers); the distal ulnar epiphysis appears at age 5 years; the radial head appears at age 5 to 7 years; the olecranon appears at age 9 to 10 years. These all close between the ages of 16 and 18 years. • The distal physis accounts for 80% of forearm growth. • With advancing skeletal age, there is a tendency for fractures to occur in an increasingly distal location owing to the distal recession of the transition between the more vulnerable wider metaphysis and the more narrow and stronger diaphysis.

Osteology • The radius is a curved bone, cylindric in the proximal third, triangular in the middle third, and flat distally with an apex lateral bow. • The ulna has a triangular shape throughout, with an apex posterior bow in the proximal third..

Osteology • The proximal radioulnar joint is most stable in supination where the broadest part of the radial head contacts the radial notch of the ulna and the interosseous membrane is most taut. The annular ligament is its major soft tissue stabilizer. • The distal radioulnar joint (DRUJ) is stabilized by the ulnar collateral ligament, the anterior and posterior radioulnar ligaments, and the pronatorquadratus muscle. Three percent of distal radius fractures have concomitant DRUJ disruption. • The periosteum is very strong and thick in the child. It is generally disrupted on the convex fracture side, whereas an intact hinge remains on the concave side. This is an important consideration when attempting closed reduction.

Biomechanics • The posterior distal radioulnar ligament is taut in pronation, whereas the anterior ligament is taut in supination. • The radius effectively shortens with pronation and lengthens with supination. • The interosseous space is narrowest in pronation and widest in neutral to 30 degrees of supination. Further supination or pronation relaxes the membrane. • The average range of pronation/supination is 90/90 degrees (50/50 degrees necessary for activities of daily living). • Middle third deformity has a greater effect on supination, with the distal third affecting pronation to a greater degree. • Malreduction of 10 degrees in the middle third limits rotation by 20 to 30 degrees. • Bayonet apposition (overlapping) does not reduce forearm rotation

Deforming Muscle Forces Proximal third fractures : • Biceps and supinator: These function to flex and supinate the proximal fragment. • Pronatorteres and pronatorquadratus: These pronate the distal fragment. • Brachioradialis: Dorsiflexes and radially deviates the distal segment. • Pronatorquadratus, wrist flexors and extensors, and thumb abductors: They also cause fracture deformity. Middle third fractures: • Supinator, biceps, and pronatorteres: The proximal fragment is in neutral. • Pronatorquadratus: Pronates the distal fragment. Distal third fractures:

Mechanism of injury Indirect: The mechanism is a fall onto an outstretched hand. Forearm rotation determines the direction of angulation Direct trauma to the radial or ulnar shaft. Pronation: flexion injury (dorsal angulation) Supination: extension injury (volar angulation) Direct:

Clinical evaluation • The patient typically presents with pain, swelling, variable gross deformity, and a refusal to use the injured upper extremity. • A careful neurovascular examination is essential. Injuries to the wrist may be accompanied by symptoms of carpal tunnel compression. • The ipsilateral hand, wrist, forearm, and arm should be palpated, with examination of the ipsilateral elbow and shoulder to rule out associated fractures or dislocations.

Clinical evaluation • In cases of dramatic swelling of the forearm, compartment syndrome should be ruled out on the basis of serial neurovascular examinations with compartment pressure monitoring if indicated. Pain on passive extension of the digits is most sensitive for recognition of a possible developing compartment syndrome; the presence of any of the classic signs of compartment syndrome (pain out of proportion to injury, pallor, paresthesias, pulselessness, paralysis) should be aggressively evaluated with possible forearm fasciotomy. • Examination of skin integrity must be performed, with removal of all bandages and splints placed in the field.

Radiographic evaluation • Anteroposterior and lateral views of forearm, wrist, and elbow should be obtained. The forearm should not be rotated to obtain these views; instead, the beam should be rotated to obtain a cross-table view. • The bicipital tuberosity is the landmark for identifying the rotational position of the proximal fragment : • Ninety degrees of supination: It is directed medially. • Neutral: It is directed posteriorly. • Ninety degrees of pronation: This is directed laterally. • In the normal, uninjured radius, the bicipital tuberosity is 180% to the radial styloid

Remodeling Potential – Variables to Consider • Age • Distance from fracture to physis • Proximal forearm fractures less forgiving • Amount of deformity • Direction of angulation • Rotational deformities will not remodel

Goals of Treatment • Regain full forearm rotation • Restore alignment and clinical appearance • 50 degrees supination, 50 degrees pronation

Nonoperative Treatment • Gross deformity should be corrected on presentation to limit injury to soft tissues. The extremity should be splinted for pain relief and for prevention of further injury if closed reduction will be delayed. • The extent and type of fracture and the child age are factors that determine whether reduction can be carried out with sedation, local anesthesia, or general anesthesia.

Nonoperative Treatment • Finger traps may be applied with weights to aid in reduction. • Closed reduction and application of a well-molded (both three-point and interosseous molds) long arm cast or splint should be performed for most fractures, unless the fracture is open, unstable, irreducible, or associated with compartment syndrome.

Nonoperative Treatment • Exaggeration of the deformity (often >90 degrees) should be performed to disengage the fragments. The angulated distal fragment may then be apposed onto the end of the proximal fragment, with simultaneous correction of rotation. • Reduction should be maintained with pressure on the side of the intact periosteum (concave side).

Nonoperative Treatment Excellent Reduction with Well Molded Cast

Nonoperative Treatment • Because of deforming muscle forces, the level of the fracture determines forearm rotation of immobilization: • The arm should be elevated The cast should be maintained for 4 to 6 weeks until radiographic evidence of union has occurred. Conversion to a short arm cast may be undertaken at 3 to 4 weeks if healing is adequate • Proximal third fractures: supination • Middle third fractures: neutral • Distal third fractures: pronation

Acceptable deformity: • Angular deformities: Correction of 1 degree per month, or 10 degrees per year results from physeal growth. Exponential correction occurs over time; therefore, increased correction occurs for greater deformities. • Rotational deformities: These do not appreciably correct.

Acceptable deformity: • Bayonet apposition: A deformity 1 cm is acceptable and will remodel if the patient is <8 to 10 years old. • In patients >10 years of age, no deformity should be accepted.

Nonoperative Treatment Plastic deformation: • Children <4 years or with deformities <20 degrees usually remodel and can be treated with a long arm cast for 4 to 6 weeks until the fracture site is nontender. • Any plastic deformation should be corrected that : • prevents reduction of a concomitant fracture, • prevents full rotation in a child >4 years, • exceeds 20 degrees

Nonoperative Treatment Plastic deformation: • General anesthesia is typically necessary, because forces of 20 to 30 kg are usually required for correction • The correction should have less than 10 to 20 degrees of angulation • The apex of the bow should be placed over a well-padded wedge, with application of a constant force for 2 to 3 minutes followed by application of a well-molded long arm cast.

Nonoperative Treatment Greenstick fractures: • Nondisplaced or minimally displaced fractures may be immobilized in a well-molded long arm cast. They should be slightly overcorrected to prevent recurrence of deformity. • Completing the fracture decreases the risk of recurrence of the deformity; however, reduction of the displaced fracture may be more difficult. Therefore, it may be beneficial to carefully fracture the intact cortex while preventing displacement. A well-molded long arm cast should then be applied.

Nonoperative Treatment After Closed Reduction and Casting • Weekly radiographs for 3 weeks to confirm acceptable alignment and rotation • overriding (bayonette) position OK • Can remanipulate up to 3 weeks after injury for shaft fractures • Angular deformity exceeding 10 degrees in child older than 8 years- consider remanipulation

Operative Indications • Unstable/unacceptable fracture reduction after closed reduction • Open fracture/compartment syndrome • Floating elbow • Refracture with displacement • Segmental fracture • Neurologic/vascular compromise • Age (girls >14 years old, boys >15 years old) • Surgical stabilization of pediatric forearm fractures is required in 1.5% to 31% of cases.

Implant Choice for Pediatric Forearm Fractures • IM nails (2 mm typically) allow for stabilization with minimal soft tissue dissection and easy removal of implants • IM fixation usually augmented with short term above elbow cast immobilization • Older children (10 years and above) may be better treated as adults with plates and screws

Operative Treatment • Intramedullary fixation: Percutaneous insertion of intramedullary rods or wires may be used for fracture stabilization. Typically, flexible rods are used or rods with inherent curvature to permit restoration of the radial bow. • The radius is reduced first, with insertion of the rod just proximal to the radial styloid after visualization of the two branches of the superficial radial nerve. • Alternate entry point just proximal to Lister's tubercle between second and third dorsal compartment

Operative Treatment • The ulna is then reduced, with insertion of the rod either antegrade through the olecranon or retrograde through the distal metaphysis, with protection of the ulnar nerve.

Open Both Bone Forearm Fracture Operative Treatment

Operative Treatment 12 Year Old- Accept Less Angulation in Older Kids

Operative Treatment • Postoperatively, a volar splint is placed for 4 weeks. The hardware is left in place for 6 to 9 months, at which time removal may take place, provided solid callus is present across the fracture site and the fracture line is obliterated.

Operative Treatment • Plate fixation: Severely comminuted fractures or those associated with segmental bone loss are ideal indications for plate fixation, because in these patterns rotational stability is needed. Plate fixation is also used in cases of forearm fractures in skeletally mature individuals. • Ipsilateral supracondylar fractures: When associated with forearm fractures, a floating elbow results. These may be managed by conventional pinning of the supracondylar fracture followed by plaster immobilization of the forearm fracture.

Metal Removal • In younger children IM fixation usually removed at 3-6 months when solid healing noted on radiographs • When plates and screws used then often implants not removed unless symptomatic

Acceptable Angulations • Case by case decisions • Closed reduction should be attempted for angulation greater than 20 degrees • How much to accept before proceeding with open reduction dependent on many factors • Angulation encroaching on interosseous space may be more likely to limit rotation

Acceptable Angulations Accepted angulation is (provided the child has at least 2 years of growth remaining): • 20 degrees of angulation in distal-third shaft fractures of the radius and ulna • 15 degrees at the midshaft level • 10 degrees in the proximal third We accept 100% translation if shortening is less than 1 cm. Although other authors recommend accepting up to 45 degrees of rotation

Acceptable Angulations

Complication Refracture: This occurs in 5% of patients and is more common after greenstick fractures and after plate removal. Malunion: This is a possible complication Synostosis: Rare complication in children. Risk factors include high-energy trauma, surgery, repeated manipulations, proximal fractures, and head injury. Compartment syndrome: One should always bivalve the cast after a reduction. Nerve injury: Median, ulnar and posterior interosseous nerve (PIN) nerve injuries have all been reported. There is an 8.5% incidence of iatrogenic injury in fractures that are surgically stabilized.

Complication 16 Year old with Rotational Malunion in older patients operative treatment preferred to maintain functional forearm rotation

Galeazzi Fracture- Radial Shaft Fracture with DRUJ Injury • relatively rare injuries in children • Usually at junction of middle and distal thirds • Distal fragment typically angulated towards ulna • Closed treatment for most • Carefully assess DRUJ post reduction, clinically and radiographically

Galeazzi Fracture Closed Reduction

Galeazzi Equivalent • Radial shaft fracture with distal ulnarphyseal injury instead of DRUJ injury • Distal ulnarphyseal injuries have a high incidence for growth arrest

Galeazzi Equivalent 12 Year Old Male GaleazziEquivalent Distal ulnar epiphysis

Distal Radius Fractures • Most commonly fractured bone in children • Metaphyseal most frequent, distal radial physeal second • Simple falls most common mechanism • Rapid growth may predispose, with weaker area at metaphysis

Distal Radius Fractures • Metaphyseal • Physeal – Salter II most common • Torus • Greenstick • Complete - Volarangulation with dorsal displacement of the distal fragment most common

Associated Injuries • Frequently distal ulnarmetaphyseal fracture or ulnarstyloid avulsion • Occasionally distal ulnarphyseal injury – high incidence of growth disturbance • Median or ulnar nerve injury – rare • Acute carpal tunnel syndrome can occur, also rare

Nondisplaced distal radius fractures treatment • Below elbow immobilization • 3 weeks • Torus fractures are stable injuries and can be treated with a removable forearm splint

Displaced distal radius fractures-treatment • Closed reduction usually not difficult • Traction (reduce shear), recreate deformity and reduce using intact periosteal hinge • Immobilize – many different positions of wrist and forearm rotation recommended • Well molded cast / splint, above or below elbow surgeon preference • 3-4 weeks immobilization

Treatment Recommendations – Reduction Attempts? “Repeated efforts at reduction do nothing more than grate the plate away.” “These injuries unite quickly, so that attempts to correct malposition after a week are liable to do more damage to the plate than good.” Rang, Children’s Fractures 1983.

Pediatric Fractures of the Forearm, Wrist and Hand