• DISTAL RADIUS FRACTURES

   

   

   

  EPIDEMIOLOGY

• Distal radius fractures are among the most common fractures of the upper extremity.

• More than 650,000 occur annually in the United States.

• Fractures of the distal radius represent approximately one-sixth of all fractures treated in emergency departments and about 16% of all fractures treated by orthopaedic surgeons.

• The incidence of distal radius fractures in the elderly correlates with osteopenia and rises in incidence with increasing age, nearly in parallel with the increased incidence of hip fractures.

• In men aged 35 years and older, the incidence is approximately 90 per 100,000 population per year and remains relatively constant until the age of 70 where a slight increase is seen.

• In women less than age 40, the incidence is approximately 368 per 100,000 population; for women 40 years and older, this incidence rises to 1,150 per 100,000 population.

• Risk factors for fractures of the distal radius in the elderly include decreased bone mineral density, female sex, white race, family history, and early menopause.

  ANATOMY

• The metaphysis of the distal radius is composed primarily of cancellous bone. The articular surface has a biconcave surface for articulation with the proximal carpal row (scaphoid and lunate fossae), as well as a notch for articulation with the distal ulna.

• Eighty percent of axial load is supported by the distal radius and 20% by the ulna and the triangular fibrocartilage complex (TFCC).

• Reversal of the normal palmar tilt results in load transfer onto the ulna and TFCC; the remaining load is then borne eccentrically by the distal radius and is concentrated on the dorsal aspect of the scaphoid fossa.

• Numerous ligamentous attachments exist to the distal radius; these often remain intact during distal

  radius fracture, facilitating reduction through “ligamentotaxis.”

• The volar ligaments are stronger and confer more stability to the radiocarpal articulation than the dorsal ligaments.

  MECHANISM OF INJURY

• Common mechanisms in younger individuals include falls from a height, motor vehicle accidents, or injuries sustained during athletic participation. In elderly individuals, distal radial fractures may arise from low-energy mechanisms, such as a simple fall from a standing height, and as such are considered a fragility fracture.

• The most common mechanism of injury is a fall onto an outstretched hand with the wrist in dorsiflexion.

• Fractures of the distal radius are produced when the dorsiflexion of the wrist varies between 40 and 90 degrees.

• The radius initially fails in tension on the volar aspect, with the fracture propagating dorsally, whereas bending moment forces induce compression stresses, resulting in dorsal comminution. Cancellous impaction of the metaphysis further compromises dorsal stability. Additionally, shearing forces influence the injury pattern, often resulting in articular surface involvement.

• High-energy injuries (e.g., vehicular trauma) may result in significantly displaced or highly comminuted unstable fractures to the distal radius.

  CLINICAL EVALUATION

• Patients typically present with variable wrist deformity and displacement of the hand in relation to the wrist (dorsal in Colles or dorsal Barton fractures and volar in Smith-type fractures or volar Bartons). The wrist is typically swollen with ecchymosis, tenderness, and painful range of motion.

• The ipsilateral elbow and shoulder should be examined for associated injuries.

• A careful neurovascular assessment should be performed, with particular attention to median nerve function. Carpal tunnel compression symptoms are common (13% to 23%) owing to traction during forced hyperextension of the wrist, direct trauma from fracture fragments, hematoma formation, or increased compartment pressure.

  RADIOGRAPHIC EVALUATION

• Posteroanterior and lateral views of the wrist should be obtained, with oblique views for further fracture definition, if necessary. Shoulder or elbow symptoms should be evaluated radiographically.

• Contralateral wrist views may help to assess the patient’s normal ulnar variance and scapholunate angle.

• Computed tomography scan may help to demonstrate the extent of intra-articular involvement.

• Normal radiographic relationships (Fig. 22.1):

  • Radial inclination: averages 23 degrees (range, 13 to 30 degrees)

  • Radial length: averages 11 mm (range, 8 to 18 mm)

  • Palmar (volar) tilt: averages 11 to 12 degrees (range, 0 to 28 degrees)

 

 

 

CLASSIFICATION

Descriptive

Open versus closed Displacement Angulation Comminution

Loss of radial length

Frykman Classification of Co les Fractures

This is based on the pattern of intra-articular involvement (Fig. 22.2).

 

 

 

 

 

 

Fernandez Classification

This is a mechanism-based classification system.

Type I: Metaphyseal bending fracture with the inherent problems of loss of palmar tilt and radial shortening relative to the ulna (DRUJ injury)

Type II: Shearing fracture requiring reduction and often buttressing of the articular segment

Type III: Compression of the articular surface without the characteristic fragmentation; also the potential for significant interosseous ligament injury

Type IV: Avulsion fracture or radiocarpal fracture-dislocation

Type V: Combined injury with significant soft tissue involvement owing to high-energy injury

Orthopaedic Trauma Association Classification of Fractures of the Distal Radius and Ulna

See Fracture and Dislocation Compendium at http://www.ota.org/compendium/index.htm.

Eponyms (Fig. 22.3)

 

 

 

• Colles fracture

  • The original description was for extra-articular fractures. Present usage of eponym includes both extra-articular and intra-articular distal radius fractures demonstrating various combinations of dorsal angulation (apex volar), dorsal displacement, radial shift, and radial shortening.

  • Clinically, it has been described as a “dinner fork” deformity.

  • More than 90% of distal radius fractures are of this pattern.

  • The mechanism of injury is a fall onto a hyperextended, radially deviated wrist with the forearm in pronation.

  • Intra-articular fractures are generally seen in the younger age group secondary to higher energy

    forces; concomitant injuries (i.e., to nerve, carpus, and distal ulna) are more frequent, as is involvement of both the radiocarpal joint and the DRUJ.

• Smith fracture (reverse Colles fracture)

  • This describes a fracture with volar angulation (apex dorsal) of the distal radius with a “garden spade” deformity or volar displacement of the hand and distal radius.

  • The mechanism of injury is a fall onto a flexed wrist with the forearm fixed in supination.

  • This is a notoriously unstable fracture pattern; it often requires open reduction and internal fixation because of difficulty in maintaining adequate closed reduction.

• Barton fracture

  • This is a shearing mechanism of injury that results in a fracture-dislocation or subluxation of the wrist in which the dorsal or volar rim of the distal radius is displaced with the hand and carpus. Volar involvement is more common.

  • The mechanism of injury is a fall onto a dorsiflexed wrist with the forearm fixed in pronation.

  • Almost all fractures of this type are unstable and require open reduction and internal fixation with a buttress plate to achieve stable, anatomic reduction.

• Radial styloid fracture (Chauffeur fracture, backfire fracture, Hutchinson fracture)

  • This is an avulsion fracture with extrinsic ligaments remaining attached to the styloid fragment. This may also be secondary to a direct blow.

  • The mechanism of injury is compression of the scaphoid against the styloid with the wrist in

    dorsiflexion and ulnar deviation.

  • It may involve the entire styloid or only the dorsal or volar portion.

  • It is often associated with intercarpal ligamentous injuries (i.e., scapholunate dissociation, perilunate dislocation).

  • Open reduction and internal fixation are often necessary.

     

    TREATMENT

• Factors affecting treatment include:

  • Fracture pattern

  • Local factors: bone quality, soft tissue injury, fracture comminution, fracture displacement, and energy of injury

  • Patient factors: physiologic patient age, lifestyle, occupation, hand dominance, associated

    medical conditions, associated injuries, and compliance

• Acceptable radiographic parameters for a healed radius in an active, healthy patient include:

  • Radial length: within 2 to 3 mm of the contralateral wrist

  • Palmar tilt: neutral tilt (0 degrees)

  • Intra-articular step-off: <2 mm

  • Radial inclination: <5-degree loss

• Carpal alignment after distal radius fracture may have the most influence on outcome following distal radius fracture.

  • Carpal alignment is measured by the intersection of two lines on the lateral radiograph: one parallel and through the middle of the radial shaft and the other through and parallel to the capitate. If the two lines intersect within the carpus, then the carpus is aligned. If the two lines intersect outside the carpus, then the carpus is malaligned.

• Several factors have been associated with redisplacement following closed manipulation of a distal radius fracture:

  • The initial displacement of the fracture: The greater the degree of displacement (particularly radial shortening), the more energy is imparted to the fracture resulting in a higher likelihood that closed treatment will be unsuccessful.

  • The age of the patient: Elderly patients with osteopenic bones tend to displace, particularly late.

  • The extent of metaphyseal comminution (the metaphyseal defect), as evidenced by either plain

    radiograph or computerized tomography, is also a factor.

  • Displacement following closed treatment is a predictor of instability, and repeat manipulation is unlikely to result in a successful radiographic outcome.

    Nonoperative

• All fractures should undergo closed reduction, even if it is expected that surgical management will be needed.

  • Fracture reduction helps to limit postinjury swelling, provides pain relief, and relieves compression on the median nerve.

• Nonoperative management is indicated for:

  • Nondisplaced or minimally displaced fractures

  • Displaced fractures with a stable fracture pattern which can be expected to unite within acceptable radiographic parameters

  • Low-demand elderly patients in whom future functional impairment is less of a priority than

    immediate health concerns and/or operative risks

• Hematoma block with supplemental intravenous sedation, Bier block, or conscious sedation can be used to provide analgesia for closed reduction.

• Technique of closed reduction (dorsally tilted fracture):

  • The distal fragment is hyperextended.

  • Traction is applied to reduce the distal to the proximal fragment with pressure applied to the distal radius.

  • A well-molded long arm (“sugar-tong”) splint is applied, with the wrist in neutral to slight

    flexion.

  • One must avoid extreme positions of the wrist and hand.

  • The splint should leave the metacarpophalangeal joints free.

• Once swelling has subsided, a well-molded cast is applied.

• The ideal forearm position, duration of immobilization, and need for a long arm cast remain controversial; no prospective study has demonstrated the superiority of one method over another.

• Extreme wrist flexion should be avoided, because it increases carpal canal pressure (and thus median nerve compression) as well as digital stiffness. Fractures that require extreme wrist flexion to maintain reduction are indicated for operative fixation.

• The cast should be worn for approximately 6 weeks or until radiographic evidence of union has occurred.

• Frequent radiographic examination is necessary to detect loss of reduction.

• The patient should work on full range of finger motion during immobilization to minimize hand stiffness.

  Operative

• Indications

  • High-energy injury

  • Secondary loss of reduction

  • Articular comminution, step-off, or gap

  • Metaphyseal comminution or bone loss

  • Loss of volar buttress with displacement

  • DRUJ incongruity

  • Open fractures

  • Associated carpal fractures

  • Associated neurovascular or tendon injury

  • Bilateral distal radius fractures

  • An impaired contralateral extremity

• Patient positioning

  • Supine with the arm supported on a radiolucent hand table

• Image positioning

  • Image intensifier positioned on the same side as the injured extremity

• Surgical approaches

  • Volar approach

    • Most commonly used approach with advent of locked plates

    • Interval is through floor of flexor carpi radialis tendon with elevation of pronator quadratus muscle

    • Transverse carpal ligament can be release through a separate incision if median nerve

      compression exists

  • Dorsal approach

    • Used to reduce and stabilize dorsal fragments

    • Interval is through 3rd dorsal compartment

    • May view articular surface via arthrotomy

  • Radial approach

    • Used to reduce and stabilize radial styloid fragments

    • Interval is between the 1st and 2nd dorsal compartments

      Operative Techniques

• Percutaneous pinning: This is primarily used for extra-articular fractures or two-part intra-articular fractures.

  • It may be accomplished using two or three Kirschner wires placed across the fracture site, generally from the radial styloid, directed proximally and from the dorsoulnar side of the distal radial fragment directed proximally. Transulnar pinning with multiple pins has also been described.

  • Percutaneous pinning is generally used to supplement short arm casting or external fixation. The pins may be removed 6 to 8 weeks postoperatively, with the cast maintained for an additional 2 to 3 weeks.

• Kapandji “intrafocal” pinning

  • This is a technique of trapping the distal fragment by buttressing to prevent displacement.

  • The wires are inserted both radially and dorsally directly into the fracture site. The wires are then levered up and then directed into the proximal intact opposite cortex.

  • The fragments are thus buttressed from displacing dorsally or proximally.

  • In addition to being relatively simple and inexpensive, this technique has been shown to be very effective, particularly in elderly patients.

• External fixation: Its use has diminished in popularity since the advent of volar locked plating

  despite low complication rates and long-term outcomes which are similar to those of locked plating.

  • Spanning (bridging) external fixation

    • Ligamentotaxis is used to restore radial length and radial inclination, but it rarely restores palmar tilt.

    • External fixation alone may not be sufficiently stable to prevent some degree of collapse and

      loss of palmar tilt during the course of healing, especially with comminuted fractures in osteopenic bone. Supplemental K-wire fixation or bone graft can be used as adjunctive fixation.

    • Overdistraction should be avoided because it may result in finger stiffness; overdistraction can be recognized by increased intercarpal distance on intraoperative fluoroscopy.

    • The external fixator is removed after 6 to 8 weeks.

  • Nonspanning (nonbridging) external fixation

    • A nonspanning fixator is one that stabilizes the distal radius fracture by securing pins in the radius alone, proximal to and distal to the fracture site.

    • It requires a sufficiently large intact segment (>1 cm) of intact volar cortex.

    • It may be better to preserve volar tilt, prevent carpal malalignment, and result in improved grip strength and hand function than spanning external fixation.

• Open reduction and plate fixation

  • Dorsal plating: This has several theoretic advantages.

    • The approach avoids the neurovascular structures on the palmar side.

    • The fixation is on the compression side of the fracture and provides a buttress against collapse.

    • Initial reports of the technique demonstrated successful outcomes with the theoretic

      advantages of earlier return of function and better restoration of radial anatomy than seen with external fixation.

    • Dorsal plating has been associated with extensor tendon complications.

    • It is less commonly performed since the introduction of locked volar plating.

    • Now it is primarily used for stabilization of isolated dorsal fragments which cannot be adequately stabilized using a locked volar plate.

  • Volar nonlocked plating

    • This has fallen out of favor since the advent of locked volar plates, since the implant may be unable to maintain fracture reduction in the presence of dorsal comminution.

    • It can be used to buttress isolated volar shear fractures (volar Barton).

  • Volar locked plating

    • Locked volar plating has increased in popularity because this implant has been shown to stabilize distal radius fractures with dorsal comminution.

    • It has surpassed external fixation as the most popular mode of fracture fixation of the distal

      radius.

    • The dorsal side of the radius may be accessed through an extension of the volar approach.

    • This allows for early range of wrist motion.

  • Fragment-specific plating

    • This has been advocated for more complex fracture patterns involving several aspects of the radial and ulnar columns.

    • The operative approach should be dictated by pre- and post-reduction radiographs.

• Intramedullary (IM) fixation

  • Have been good reported results using IM fixation with locking screws placed through the radial styloid for treatment of simpler fracture patterns

• Adjunctive fixation

  • Supplemental graft may be autograft, allograft, or synthetic graft.

  • Adjunctive Kirschner wire fixation may be helpful with smaller fragments.

• Arthroscopically assisted intra-articular fracture reduction

  • Although arthroscopy has been invaluable at enhancing existing knowledge of associated soft tissue lesions in distal radius fractures, it is controversial whether this technique provides outcomes superior to those of conventional techniques.

  • Fractures that may benefit most from adjunctive arthroscopy are (1) articular fractures without metaphyseal comminution, particularly those with central impaction fragments; and (2) fractures with evidence of substantial interosseous ligament or TFCC injury without large ulnar styloid base fracture.

• Ulna styloid fractures: Indications for fixation of ulna styloid are controversial. Some authors have advocated fixation for displaced fractures at the base of the ulna styloid. After fixation of the distal radius, one should assess stability of the DRUJ; laxity of the DRUJ can be compared to the noninjured side.

  COMPLICATIONS

• Median nerve dysfunction: Management is controversial, although there is general agreement about the following:

  • A complete median nerve lesion with no improvement following fracture reduction requires surgical exploration (rare).

  • Median nerve dysfunction developing after reduction mandates release of the splint and

    positioning of the wrist in neutral position; if there is no improvement, exploration and release of the carpal tunnel should be considered.

  • An incomplete lesion in a fracture requiring operative intervention is a relative indication for carpal tunnel release.

• Malunion or nonunion: This typically results from inadequate fracture reduction or stabilization; it

  may require internal fixation with or without osteotomy with bone graft. Malunion in the elderly without functional disturbance is generally the rule.

• Complications of external fixation include reflex sympathetic dystrophy, pin tract infection, wrist and finger stiffness, fracture through a pin site, and radial sensory neuritis. Open pin placement is advisable to allow visualization of the superficial radial nerve.

• Posttraumatic osteoarthritis: This can be a consequence of radiocarpal and radioulnar articular injury, thus emphasizing the need for anatomic restoration of the articular surface. It can also result from intra-articular screw placement during surgery. A tilted lateral view of the distal radius has been described to obtain better visualization of the distal radial articular surface and assess the appearance of hardware placed into the radial–carpal joint during surgery.

• Finger, wrist, and elbow stiffness: This occurs especially with prolonged immobilization in a cast or with external fixation; it emphasizes the need for aggressive occupational therapy to mobilize the digits and elbow while wrist immobilization is in place, as well as a possible supervised therapy regimen once immobilization has been discontinued.

• Tendon rupture, most commonly extensor pollicis longus, may occur as an early or late complication of distal radius fractures, even in cases of minimally displaced injuries. Degeneration of the tendon, owing to vascular disruption of the tendon sheath as well as mechanical impingement on the callus, results in attrition of tendon integrity. Dorsal plating has been most often associated with extensor tendon complications. There have been reports of both volar and dorsal tendon rupture using volar locked plates secondary to either (1) screws/pegs protruding past the dorsal cortex and irritating the extensor tendons or (2) distal placement of the plate past the watershed with impingement of the plate on the flexor tendons. A recently described “dorsal tangential view” can be used to identify screw penetration into the dorsal compartments during operative fixation. This view is taken with the wrist flexed 75 degrees while the forearm is placed between two ends of the C-am with the dorsal forearm tangential to the x-ray beam.

• Midcarpal instability (i.e., dorsal or volar intercalated segmental instability) may result from radiocarpal ligamentous injury or a dorsal or volar rim distal radius disruption. One should maintain a high index of suspicion in fractures where the lunate facet is significantly displaced from the radial styloid. Recent studies have failed to show a correlation between intercalated segmental instability on radiographs and patient outcomes at 1 year. It is unknown whether this radiographic finding will affect longer term outcomes.