13: Distal Radius Fractures

PROCEDURE 13 Distal Radius Fractures



Neil J. White, Paul J. Duffy



image


External Fixation




Indications




PITFALLS



• If the goals of reduction cannot be obtained using external fixation (with or without augmentation), then the surgeon must be equipped to convert to an open procedure. This occurs in up to 10% of distal radius fractures.
image It is an error to leave the operating room without obtaining appropriate radial length, inclination, and tilt and a reduced articular surface regardless of reduction and fixation techniques employed.

• Scaphoid or lunate dipunch injuries generally require a direct reduction through open or limited open approaches. These injuries are difficult to treat with external fixation alone.


image Spanning external fixation
• This technique can be used for most fractures of the distal radius that have failed an attempt at closed reduction, excluding volar displaced fracture patterns (Smith’s) and volar or dorsal shear patterns (Barton’s).

• Spanning external fixation can be used as primary fixation or to augment or neutralize other techniques of fixation.

image Nonspanning external fixation
• This technique can be used for unstable extra-articular or minimally displaced articular distal radius fractures that have failed an attempt at closed reduction.

• It can also be used for severe intra-articular fractures where there is space for the distal pins after reduction of the intra-articular component.
♦ One centimeter of intact volar cortex is generally required for pin fixation.

• Nonspanning external fixation can be combined with distal radial osteotomy for the treatment of distal radius malunion.

• Nonspanning external fixation cannot be used in the pediatric patient with an open physis.


Examination/Imaging




Controversies



• Some authors prefer to avoid external fixation in patients with osteoporosis, while others advocate its use considering that all stabilization techniques are severely compromised in this population.

• External fixation should be reserved for the independent adult. It should be used cautiously in patients with mental illness.


PHYSICAL EXAMINATION



image Treatment should be directed according to patient’s functional status, occupational requirements, hand dominance, pertinent medical history, and expectations.

image Examination should focus on identifying other systemic or upper extremity injuries. After diagnosing, prioritizing, and treating systemic injuries, the limb needs to be assessed.
• It is essential to examine the forearm and elbow as well as the carpus. Galeazzi, Monteggia, and Essex-Lopresti lesions are often missed in the forearm, while carpal ligament injuries are often missed in the hand (Fig. 1).

• The limb must be inspected for open wounds. They are generally low grade and occur on the volar surface of the wrist or occasionally on the ulnar side of the wrist when associated with an ulnar styloid fracture).

• A careful neurologic examination must rule out neurologic insult. This most commonly occurs in the median nerve and may require an urgent decompression if a severe or progressive neurologic deficit is found.

• Although acute tendon ruptures are exceedingly rare, the surgeon should inform the patient of the possibility of late extensor pollicis longus (EPL) rupture.

image

FIGURE 1




Treatment Options



• Most distal radius fractures considered for surgery should have failed an attempted closed reduction. Exceptions include open fractures, polytrauma, ipsilateral upper extremity injuries, and associated neurologic insult requiring surgery.

• Many treatment options exist for the distal radius fracture. Most can be used in isolation or in conjunction with external fixation. The general principle is to do what works well and is reproducible in your hands.
image A second reduction can be attempted, but the results are usually similar to the first attempt. It should only be attempted when at least one or more parameters have been changed to significantly increase the chances of success. Finger traps, deeper sedation, or more experienced physician and assistants may all increase chances of successful reduction.

image Closed reduction with percutaneous pin fixation ± external fixation.

image Closed reduction with intrafocal pin fixation ± external fixation (Kapandji).

image Mini-open reduction with percutaneous or intrafocal pin fixation ± external fixation.

image As above with bone graft or substitute.

image Arthroscopic assisted reduction with any of the above.

image Open reduction and internal fixation with dorsal or volar plating, or with fragment-specific fixation. This may also be combined with any or all of the above techniques.


IMAGING STUDIES



image Anteroposterior (AP), lateral, and oblique films should be obtained for initial assessment. The patient should be splinted for comfort prior to transport to the diagnostic imaging department.

image Repeating these films postreduction usually provides more information about the specific fracture fragments. Postreduction films should be obtained even if the decision to go to the operating room has already been made, such as for open fracture.
• Radiographic parameters for acceptable reduction must be assessed preoperatively and repeatedly during surgery.

• Acceptable and normal values differ; these numbers should be intimately well known to the treating surgeon.

• Radial length
♦ Normal: comparing the lunate facet to the ulnar head ± 2 mm

♦ Acceptable reduction: not more than 2 mm shortening compared to ulnar head or contralateral side

• Volar tilt
♦ Normal: 11° volar

♦ Acceptable reduction: neutral tilt

• Radial inclination
♦ Normal: 20° from radial styloid to ulnar edge of lunate facet

♦ Acceptable reduction: 10°

• Intra-articular displacement
♦ Normal: none

♦ Acceptable reduction: 2 mm of intra-articular step or gap

image There should be a low threshold to include films of the ipsilateral elbow and forearm.

image Contralateral films can be obtained to assess the patient’s normal anatomy. This may be useful in assessing anatomic variants or judging radial length. This is not routinely done.

image Traction films can add value in identifying specific fracture fragments. These are easily obtained in the operating room utilizing the image intensifier.
• Figure 2 shows traction views of a 47-year-old female with an injury to her dominant arm; these were taken in the operating room prior to deciding on a definitive treatment plan. The fracture was deemed too comminuted for open fixation and therefore was treated with a spanning fixator in combination with a mini-open dorsal incision and supplementary Kirschner wires (K-wires). This example demonstrates the value of these views in understanding the fracture pattern.

image Computed tomography is occasionally indicated for distal radius fractures. If utilized, it provides the most information after a reduction maneuver is performed. It should be reserved for use when the surgeon is trying to determine the size, position and orientation of fracture fragments or fragment orientation.

image

FIGURE 2



Surgical Anatomy



image The bony anatomy of the distal radius must be intimately understood. If distal radial pins are used, this is paramount.

image The articular surface is a triangle with its base at the lunate facet and its apex the radial styloid. It slopes in an ulnar and volar direction (Fig. 3A).

image Lister’s tubercle sits dorsally and acts as a fulcrum for the EPL tendon, which passes on its ulnar side. This acts as a landmark to identify and protect the EPL for pin placement or mini-open procedures.
• Knowledge of the six dorsal compartments is necessary for fixator pin placement on either side of the third (EPL) compartment (see Fig. 3A).
♦ Compartment I: abductor pollicis longus and extensor pollicis brevis (Fig. 3B)

♦ Compartment II: extensor carpi radialis longus and brevis

♦ Compartment III: extensor pollicis longus

♦ Compartment IV: extensor digitorum communis and extensor indicis

♦ Compartment V: extensor digiti minimi

♦ Compartment VI: extensor carpi ulnaris

image The superficial branch of the radial nerve and its branches are at risk during proximal and distal fixator pin placement as well as during percutaneous K-wire placement from the radial styloid. Painful neuromata can cause significant morbidity postoperatively.

image The dorsal-radial anatomy of the radius in the middle third must be well known for proximal fixator pin placement.
• From radial to ulnar, the bone is covered by the flat tendons and musculotendinous junctions of the brachioradialis, extensor carpi radialis longus and brevis, and crossing abductor pollicis longus muscles.

• The superficial branch of the radial nerve exits from under the brachioradialis and crosses the abductor pollicis longus and extensor pollicis brevis after exiting from below the brachioradialis (Fig. 4).

image For spanning fixator pins, the anatomy of the second digit must be understood.

image

FIGURE 3

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Jun 7, 2016 | Posted by in ORTHOPEDIC | Comments Off on 13: Distal Radius Fractures

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