Nonoperative Treatment of Distal Radius Fractures

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CHAPTER 2 Nonoperative Treatment of Distal Radius Fractures

Joseph J. Dias, MD, FRCS, FRCS (Edin), MBBS

Indications

The fractures of the distal radius best suited for nonoperative treatment are (1) undisplaced and minimally displaced stable fractures, (2) bending fractures in good bone, and (3) intra-articular fractures where there is almost no step between the intra-articular fragments.

Radiographic Criteria for Nonoperative Treatment

On the assumption that the wrist was normal prior to the fracture of the distal radius my colleagues and I recommend the following radiographic criteria for nonoperative treatment after reduction if required: dorsal tilt of the distal radius articular surface of less than 10 degrees, intra-articular step of less than 1 mm, and 3 mm of ulnar variance. In very osteoporotic individuals or those who are unwell or physiologically elderly, however, we may accept up to 20 degrees of dorsal tilt, an intra-articular step of 2 mm, and 5 mm of ulnar-positive variance.

Undisplaced and Minimally Displaced Fractures

It is usual to treat undisplaced or minimally displaced stable fractures of the distal radius in a below-elbow plaster of Paris cast for 4 to 6 weeks. The wrist is usually immobilized in slight extension so as to allow some activities of daily living. Even in undisplaced fractures, the cast is applied with some molding to reduce the risk of loss of position of the fracture during bone healing.

The cast is made up of an 8-inch plaster of Paris slab extending from the distal palmar crease around the radial aspect of the wrist and proximally up to the proximal third of the forearm. A hole is cut out for the thumb. The pronated forearm is held by two assistants, one holding the arm just above the elbow and the other holding the extended fingers. These assistants must give slight traction along the line of the forearm (Fig. 2-1). The hand and forearm are covered firmly with synthetic wool, and the plaster slab is applied to extend around the radial side of the forearm and wrist and ulnarward both dorsally and on the palmar side. This slab is then firmly bandaged in place with a crepe bandage. As the plaster sets it is molded with three points of compression to counter the dorsal bending deformity of the distal radius fracture. The palmar point of compression overlies the site of the fracture and forms the fulcrum over which the dorsal two compression points stretch the broken bone, thereby countering the dorsal bending tendency of such a fracture (Figs. 2-2 and 2-3).

FIGURE 2-1 Traction of the Hand. The patient is supine with the shoulder abducted, the elbow flexed to a right angle, and the forearm pronated. One assistant holds the arm and provides countertraction as the other pulls on the index and middle fingers.

FIGURE 2-2 The precise position of the physician’s hands in order to mold the fracture into its proper alignment is demonstrated. The physician is positioned facing the patient’s head. The physician’s hand near the patient is used to provide the fulcrum for the molding and lies close to the fracture but proximal to it. The physician’s hand away from the patient is used to mold the fracture by pressing the thenar eminence over the distal fragment of the fracture. This should stretch the probably intact dorsal periosteum and reduce the fracture, provided that the palmar cortex at the site of the fracture is not comminuted.

FIGURE 2-3 The below-elbow plaster of Paris slab is demonstrated with the smooth molds apparent.

The cast is a radially based gutter slab encompassing four fifths of the circumference of the forearm. This leaves the ulnar side of the forearm free to accommodate for any immediate swelling. The bandaging can be tightened in the first 2 weeks as the swelling reduces. Alternatively the cast can be reapplied. The distal extent of the plaster of Paris slab extends to the distal palmar crease on the ulnar side and the proximal palmar crease on the radial side to allow full flexion of the metacarpophalangeal joints over the distal palmar edge of the cast.

In the initial day or two after reduction, patients are advised to clench and unclench the hand on the affected side and to elevate the hand on pillows when at home. Attention must be paid not to flex the elbow above a right angle to avoid circulatory compromise and stretching of the ulnar nerve. The patients are encouraged to use the hand for light activities of daily living and are told how to avoid getting the plaster wet when bathing. They are encouraged to return to the clinic if they experience any problems or if the plaster of Paris slab breaks or becomes soft. Patients are also provided with written instructions on care of the plastered extremity.

Do Undisplaced Fractures Need Immobilization?

Undisplaced or minimally displaced fractures can be safely treated in a plaster of Paris slab. Stable fractures can also be safely treated without immobilization. In a prospective randomized study of 97 fractures, Dias and associates ¹ demonstrated that the treatment of such fractures without a cast did not result in greater displacement or more discomfort than those treated in a cast. Moreover, more patients treated without immobilization recovered grip and movement within 8 weeks compared to those immobilized in a cast.

Displaced Fractures

Extra-articular Fractures

Extra-articular displaced fractures need to be carefully manipulated back into place. The technique described by Charnley ² needs to be followed to disimpact the fracture by giving traction. Traction may be easily given using manual distraction or alternatively may be provided by finger traps and weights as described by Earnshaw and coworkers.³ Once the fracture has been disimpacted, the wrist can be manipulated in pronation to counter the tendency of the distal fragment to supinate. Although flexion of the wrist has been suggested to counter the dorsal angulation of the distal radius, the fracture can be gently manipulated to correct the dorsal tilt by molding. The physician stands facing the patient’s head, on the thumb side of the pronated forearm. The physician’s hand nearest the patient supports the palmar side of the radius just proximal to the fracture. The physician’s hand away from the patient is used to push down on the dorsum of the distal fragment (see Fig. 2-2). The fracture is then assessed under fluoroscopy. If the position is satisfactory, especially with the traction released, a plaster slab is applied as described above.

Intra-articular Fractures

When there is an intra-articular nondisplaced fracture line, the fracture is treated exactly as an extra-articular fracture but care is exercised to ensure that the intra-articular fracture does not displace during reduction. This is done by depending more on traction to realign the fracture.

If there is displacement of the intra-articular fracture, the position is checked after traction. A cast may be applied if the fracture and other factors indicate it or the physician decides to try nonoperative treatment in the first instance. Monitoring, discussed below, needs to be meticulous, however, and the physician must be prepared to change the method of management if the fracture displaces.

Severely displaced or comminuted fractures cannot be treated satisfactorily using a cast. Casting can only be considered in these cases if the physiologic state of the patient does not permit surgical intervention. The physician must anticipate a high rate of loss of position, with remanipulation not offering much hope of improved position.⁴

Aftercare

Nonoperative treatment in a plaster of Paris gutter slab demands regular and meticulous monitoring of the fracture and the injured limb. In our unit it is usual to review the patient, the fracture, and the injured extremity in the second week after injury. This is used to (1) confirm that the position of the fracture is maintained by obtaining radiographs of the injured limb in the cast; (2) check that the cast is still snug as the swelling of the wrist and hand settles; (3) ensure that the cast is comfortable and there is no localized discomfort to suggest excess pressure; (4) ensure that the patient is moving and exercising the hand using the six-pack of hand exercises; and (5) establish that all tendons, particularly the extensor pollicis longus tendon, and all nerves, particularly the median nerve, are functioning normally.

The plaster slab is retained until the next appointment, which occurs in the sixth week after injury. At this clinic visit the plaster slab is removed and the following are done: (1) Radiographs of the wrist are taken to confirm whether the position of the fracture obtained immediately after injury and confirmed in the second week is maintained. (2) The state of the tendons is confirmed. The extensor pollicis longus tendon is assessed by asking the patient to actively extend the thumb interphalangeal joint and noting that the interphalangeal joint extends and that the patient does not experience any soreness near Lister’s tubercle to suggest an impending rupture. (3) Nerve function, especially that of the median nerve, is assessed. (4) Attention is then turned to the wrist and the following documented:

• The persistence of swelling and the appearance of the hand and whether it is deviated radially to suggest a radial inclination malunion of the distal radius

• The prominence of the head of the ulna and the direction of this prominence, whether palmar or dorsal

• The range of wrist movement is measured with a goniometer to document the extension, flexion, and radial and ulnar inclination.

• Forearm rotation is measured.

• Any pain and its severity on movement, particularly on the ulnar side of the wrist, is noted.

• Grip strength is recorded.

Based on these observations, the patient is taught wrist exercises, concentrating on wrist circumduction and forearm rotation. Formal physiotherapy may need to be organized if the wrist and forearm range is less than half of the opposite, uninjured side. The patient is advised to resume activity but to avoid heavy work and any activity or sport where there is a real risk of falling. This is because bone healing is still progressing.

If the assessment and function of the wrist and hand are satisfactory, the patient may be discharged with advice and instructions to return if there are any concerns. Patients with significant stiffness need to be monitored over the subsequent 6 weeks. Any concerns about tendons, nerves, or algodystrophy demand immediate appropriate investigation and frequent visits until such concerns are resolved or the appropriate treatment instituted.

Advantages, Disadvantages, and Limitations of Nonoperative Treatment

Advantages

The advantage of nonoperative treatment of a distal radius fracture is that it does not interfere with the intricate sequence of healing events at the fracture site, the patient is not exposed to the risks of surgery, and hand function recovery can begin immediately. After the early period, patients are encouraged to return to work if able.

Disadvantages

The disadvantage of nonoperative management is that it requires the wrist to be immobilized for 4 to 6 weeks. The cast imposes restrictions, particularly in bathing and driving. Patients cannot return to some occupations with a cast. For example, surgeons could not operate and those dealing with the preparation of food could not safely perform their duties when the wrist is incarcerated in a cast.

Limitations of Cast Immobilization

It must be clearly recognized that a cast cannot counter shortening at the fracture site either due to compaction of osteoporotic trabeculae or to comminution of a significant circumference of the metaphysis of the distal radius. Fractures with these attributes will lead to healing of the distal radius in a shortened position. A formal decision is required from the outset that such shortening of bone is acceptable for that particular patient. If it is not acceptable, alternative techniques to counter shortening of the distal radius need to be considered.

A plaster of Paris cast also may not maintain the reduction of a significant intra-articular step. If a cast is used for such a fracture, it needs to be monitored closely during the initial 2 weeks and any redisplacement of the fracture needs to be addressed.

For bending or minimally displaced fractures, the degree of swelling of the injured limb will help predict the risk of loss of a close fit of the plaster of Paris slab, with the consequent loss of fracture position. Patients with much swelling need to be watched carefully during the first 2 weeks, and the threshold for a change of plaster with a remanipulation should be low.

The shape and size of the forearm and wrist determine the security of immobilization in a plaster of Paris cast. In obese individuals with short forearms, the girth of the forearm is such that it is difficult to apply a plaster and mold it sufficiently to counter the dorsal bending force at the fracture site. The security of immobilization of the fracture in an obese person with a short forearm is less than that in a slender patient with a long forearm. The clinician needs to monitor the former type of patient carefully, as these patients are at greater risk of having their reduced fracture of the distal radius displace in the cast and heal in a misplaced position.

The physician must be prepared to change the method of immobilization if the fracture is showing signs of unacceptable displacement. The best person to decide on nonoperative treatment of the distal radius fracture is someone who is competent and proficient in all methods of intervention including nonoperative treatment.

Advice to Patients

Nonoperative treatment of distal radius fractures is an established method of management, and most fractures of the distal radius are treated in this manner internationally. It is, however, important to give good advice to patients so that they know what to expect from such management.

Loss of Position and Malunion

The biggest risk with nonoperative treatment of distal radius fractures is loss of position. Mackenney and colleagues ⁵ carefully investigated factors that could help predict loss of position after manipulation and established that the patient’s age, initial metaphyseal comminution, and shortening promoted such a loss. The rate of malunion, defined as shortening of 3 mm and a dorsal tilt of 10 degrees, has been calculated as 27% for minimally displaced fractures and 60% for initially displaced fractures. This rate has also been established by other studies. Dias and associates⁶ demonstrated that osteoporosis caused greater impaction at injury, a greater early loss of position, and a greater progression of deformity during the subsequent healing phase after the cast was removed because osteoporotic bone was less able to resist the deformation of bone caused by the loads borne by the wrist during everyday activity.

Recovery of Movement

It is usual to recover almost a full range of wrist and forearm rotation after distal radius fractures treated nonoperatively within 1 year.⁶^–⁸

The outcome in the long term also remains satisfactory, with no patient treated nonoperatively changing occupation over a lifetime.⁹

Osteoarthritis After Nonoperative Treatment

Gartland and Werley ¹⁰ reviewed 60 distal radius fractures around 18 months after injury and found no arthritis if the fracture was undisplaced and mild arthritis in 11% of 27 undisplaced intra-articular fractures and 40% of 26 displaced intra-articular fractures.

Smaill ⁸ reported on the results of 41 fractures 5 years after injury and found that 10 (24%) had some narrowing of joint space, but only 3 had minor aching symptoms. This rate of between 21% and 33% is unchanged for minimally displaced fractures over the long term of between 32 and 38 years.^9,¹¹

Knirk and Jupiter ¹² related the presence of radiologic arthritis to the step in the intra-articular fracture and reported an 11% arthritis rate if the joint was congruous but a 95% arthritis rate if the joint was not congruous. Their data, however, had 21 cases of intra-articular fractures treated nonoperatively and 8 (38%) had slight decrease of joint space at 6.7 years after injury. This is similar to the 40.5% slight decrease in joint space reported by Kopylov and coworkers⁹ in 47 intra-articular fractures seen 32 years after injury. Ford and associates¹¹ reported that 24 of 40 (60%) intra-articular fractured wrists had radiologic arthritis at least one grade worse than the other wrist 38 years after injury. They calculated that the odds of developing arthritis in the fractured wrist doubled (2.4 times) with 2-mm shortening and tripled (3.2 times) in intra-articular fractures.

The possibility of remodeling of the step also needs to be borne in mind. This has been demonstrated by Ford and colleagues ¹¹ in a prospective study following patients with fractures over 9 years. Arthritis may not be completely avoided if there is significant damage to the articular cartilage at the time of injury.

The observation that a step of greater than 2 mm results in osteoarthritis may be less true for nonoperatively treated fractures because the step may decrease with loading of the hand as the carpus pushes the articular step displacement into better alignment. This may explain why the rate of osteoarthritis is greater in fractures that are partly fixed with wires and other metal ¹² where one column is better fixed than the other, resulting in inadequate correction or loss of correction during healing. This promotes the formation of a step within the articular surface, which may result in early onset of arthritis. The fixation device prevents the leveling of the intra-articular displacement and, by maintaining the step, promotes degenerative change.

All alternative methods of intervention must be able to, at the very least, deliver the rate and severity of osteoarthritis following nonoperative treatment or improve on it. The information available at present does not suggest that internal fixation methods have delivered an improved rate,^12,¹³ even if one were to discount the occasional serious and irreversible complications of fixation, such as screws cutting out into the radiocarpal joint and destroying it.

Tendon Rupture

The extensor pollicis tendon can rupture even after nonoperative treatment of distal radius fractures. The rate of rupture is very low, between 0.3% (14 of 4000),¹⁴ 1.2% (7 of 565),¹⁵ and 2% (4 of 207).¹⁶ Up to 50% of ruptures of this tendon are due to a distal radius fracture.¹⁷ It usually occurs soon after the cast is removed, at between 4 and 12 weeks after injury, and is often seen after minimally displaced fractures.

The tendon may fray over a sharp edge at the fracture site or as it is contained in an osseoligamentous third extensor compartment pulley. Its circulation could be compromised, causing an ischemic rupture. Heidemann and associates ¹⁸ were able to demonstrate encroachment of the third extensor compartment by the edge of the fracture at Lister’s tubercle using CT scans.

The usual treatment, if needed, is a transfer of the extensor indicis proprius tendon to the extensor pollicis distal tendon with satisfactory but incomplete restoration of thumb extension.¹⁷ Although rare, isolated cases of rupture of flexor tendons have been reported, and there are also a very few cases of rupture of more than one tendon.

Nerve Problems

Nerve symptoms occur in between 6% and 17% of patients.^7,^15,¹⁶ Ulnar nerve and radial nerve symptoms are less common.

Stewart and coworkers ⁷ recorded that symptoms of median nerve dysfunction after nonoperatively treated distal radius fracture, with altered feeling in the thumb, index, middle, and ring fingers, occurred in 17% of 209 patients with distal radius fractures, and if treated nonoperatively, resolution of symptoms occurred in 55%.

Increasing symptoms may indicate the need for a carpal tunnel release. The prognosis must be guarded, however, as the consequences of a significant nerve injury will not be reversed by surgical release of the flexor retinaculum. It is our approach to identify nerve symptoms at the initial presentation and monitor for the first day or two if there is no other reason to operate. Usually these symptoms improve. If the symptoms do not improve and especially if the nerve symptoms worsen, we recommend an immediate flexor retinaculum release.