What Is an Adequate Reduction?

In an operatively treated fracture, anatomic reduction is the standard. In a closed reduction, a less than anatomic reduction can still be acceptable. However, there is significant debate about what and how much malreduction can be tolerated. The data on intra-articular incongruity are more consistent than the data on extra-articular deformity. Any joint incongruity is at increased risk for degenerative changes and therefore should probably be treated operatively.

With regard to the extra-articular aspect of the reduction, loss of radial length causes two problems. First, it can lead to incongruency of the DRUJ and result in pain and interference with pronation and supination. Second, it can lead to ulnocarpal impaction. Loss of radial inclination leads to radial deviation of the hand and subsequently causes scaphoid flexion and an increase in the scapholunate angle. Volar or dorsal translation of the distal radius can create an adaptive midcarpal instability, since the carpus compensates for the altered radial position.

One should also remember two other aspects when considering adequacy of a reduction. First, in most studies there is some correlation between the quality of the initial reduction and the final outcome. Second, there is invariably some loss of reduction when comparing the initial with the final radiographic results ( Fig. 8-1 A–H). This suggests that if one thinks the initial reduction is questionable, the final result will likely not be acceptable.

Distal radius fracture in a 73-year-old woman who fell . A, Anteroposterior view demonstrates loss of inclination but maintenance of radial length versus ulna. B, Lateral view demonstrates small amount of dorsal comminution and 5 degrees dorsal alignment. C, One week post-casting, anteroposterior view shows question of lunate facet incongruity. D, One week post-casting shows no change in position. E, Three weeks post-casting shows further loss of radial inclination and length. F, Three weeks post-casting shows increased dorsal tilt. G, Six weeks post-casting shows fracture resorption and incongruity at lunate facet. H, Six weeks post-casting demonstrates 20-degree dorsal tilt.

With regard to the amount of malreduction that can be accepted, in a study of 146 patients, Aro and Koivunen found that a fair or poor result was found in only 4% of fractures with shortening of less than 3 mm, in 25% of fractures with shortening of 3 to 5 mm, and in 31% of fractures with more than 5 mm of shortening. Grip strength was 90% when shortening was 2 to 3 mm, but 65% when shortening was greater than 5 mm. From a biomechanical basis, up to 10 degrees of dorsal tilt can be accommodated without substantially changing the load transmission from radius to ulna. Most clinical studies have demonstrated a correlation between outcomes and dorsal tilt, with tilt of over 10 to 15 degrees dorsal being indicative of worse outcomes.

An interesting recent study suggests that malreduction is perhaps better tolerated in older patients. In a study of 216 extra-articular fractures, patients over 65 showed no correlation between DASH/PRWE scores and radiographic parameters of reduction at 1 year ( Fig. 8-2 A–D). There was an increased risk of worse functional outcome with malreduction in younger patients.

A and B, Fracture in a 75-year-old woman who has lived independently. Surgery was recommended, but the patient declined. Fracture was reduced with a hematoma block. C and D, Despite continued recommendation during follow-up for operative fixation, this was declined. Final position of the fracture is shown. Patient reports no pain with activities of daily living, does not feel limited by it in any way, and still lives independently. She states “it just looks a little funny.”

Several conclusions can be drawn from the previous data. (1) Any intra-articular incongruity should not be accepted except in the infirm, and is likely best treated operatively. (2) Initial fracture position and initial reduction have some correlation with the final position. (3) A poor anatomic result does not preclude a good functional result; however, the better the anatomic result (particularly as it relates to radial length), the more likely there will be a good functional result. (4) There is significant variability in correlation of anatomic and functional results and probably no firm cut-off; however, radial shortening greater than 3 mm or dorsal angulation greater than 10 degrees may be problematic. (5) The older the patient, the more likely a malreduction may be acceptable.

What Are the Risk Factors for Instability?

LaFontaine and colleagues identified five variables that correlated with a potential loss of reduction: dorsal angulation of more than 20 degrees, dorsal comminution, intra-articular fracture, ulnar fracture, and age over 60 years. The investigators found that fractures of patients with more than three of these variables were unstable after closed reduction and casting. Others have suggested that the amount of axial compression is most correlated with instability. Fractures with 2 mm of initial axial compression had a 65% chance of healing in an acceptable position. Fractures with 5 mm of shortening had only a 20% chance of healing in an acceptable position.

Even nondisplaced fractures are at risk for subsequent displacement. Leone and colleagues found that one third of nondisplaced fractures in patients over 65 went on to a malreduction with conservative care.

With regard to the likelihood that a reduction will be maintained, keep in mind the findings from the trial of Earnshaw and associates. In significantly displaced fractures (average 24 degrees dorsal angulation, all greater than 10 degrees dorsal and greater than 5 mm short), even with a reduction to approximately neutral angulation and 2 mm short, at 1 week 50% displaced to more than 5 mm short or more than 10 degrees dorsal. By the fifth week, only 29% remained adequately reduced, and only 9% stayed at neutral or better tilt and less than 2 mm short. In contrast, in the trial of Kreder and associates, which was looking at minimally displaced fractures (less than 10 degrees of dorsal angulation), only 9% displaced to what was deemed an unacceptable position (less than10 degrees dorsal angulation).

Type of Reduction Performed

Closed reduction is typically performed either by manual manipulation, as described by Sir Robert Jones, or by finger-trap traction, as described by Bohler and Caldwell. In a prospective randomized comparison of Earnshaw and colleagues, no differences were seen in the efficacy of the two techniques. In the emergency room or office, a combination of both techniques is typically performed. A hematoma block is performed and the patient is placed in finger traps. Ten pounds of weight are placed on the patient’s upper arm with the elbow at 90 degrees. The patient is given about 10 minutes for muscles to fatigue and for ligamentotaxis to provide some reduction. The fracture is then additionally manipulated. Sometimes the fracture is accentuated to disimpact or unlock the volar cortex followed by volar and ulnar pressure with the surgeon’s thumb on the dorsal aspect of the distal fragment. If one anticipates a difficult reduction, then propofol sedation, axillary block, or general anesthesia may significantly improve the probability of achieving a good reduction.

One of the challenges in a closed reduction is restoration of palmar tilt. Axial traction on the wrist can bring the stout palmar ligaments out to length, but as these resist the majority of the axial pull, there is little force through the weaker dorsal ligaments to restore palmar tilt. Neutral volar tilt is typically about the best that is achieved with a significantly displaced fracture.

Type of Initial Splint/Cast

There is little evidence to suggest that a sugar-tong splint is more effective than a short-arm splint. Bong and associates in a randomized trial of 85 displaced distal fractures of the radius defined stability as radial shortening less than 4 mm, loss of volar tilt less than 10 degrees, radial shift less than 2 mm, dorsal comminution less than 50%, and intra-articular displacement less than 2 mm. Five of 18 stable fractures in a short-arm radial gutter splint lost reduction compared with 7 of 22 in a sugar-tong splint. Of unstable fractures, 11 of 20 in a short-arm construct lost reduction compared with 10 of 25 in a sugar-tong splint. There were no significant differences between the groups at the predetermined follow-up interval of 8 days. Three decades ago, Pool also demonstrated no difference between short-arm and long-arm splinting.

Although the data of Bong and associates demonstrate no statistical difference between a sugar-tong splint and a short-arm splint, this is not the same as saying statistically that they are the same. Furthermore, if one considers a trend, there is a trend toward improved results, particularly in unstable fractures, with the use of a sugar-tong splint. For this reason, until further studies examine this issue, we recommend a sugar-tong splint for the initial splinting of unstable distal radius fractures.

An effective sugar-tong splint should be molded around the elbow and should use the three-point contact casting technique described by Charnley. This technique involves application of two points of contact proximally and distally to the fracture on the side of the concavity of the initial angulation and a counterpoint of contact at the fracture level on the convexity of the initial angulation.

Given the decrease in swelling over the first few weeks, it may be necessary to rewrap the initial splint. If there is significant concern for fracture stability, it is recommended that the initial splint be maintained for 3 weeks before being changed to a short-arm construct because the risk of displacement drops considerably by 3 weeks after the injury.

Final Splint/Cast Construct

Virtually everything has been tried in the conservative care of distal radius fractures. A review of the literature gives an almost fatalistic view that the fracture is likely to behave in a way that is primarily based on the initial injury, bone quality, and quality of reduction, and less on the type of immobilization.

Although both pronated and supinated forearm positions have been advocated, data are not convincing to support extreme positions of rotation. A hyperpronated position puts any potential DRUJ injury at risk for instability. Besides being uncomfortable, a hypersupinated position also makes pronation challenging to recover. Comfortable pronation is crucial to many modern jobs that involve keyboard work. The argument for supination is to decrease the deforming force of the brachioradialis. Advocates of a pronated position suggest its favorable effect on relaxing the pronator quadratus.

In a somewhat counterintuitive study, Gupta suggested in a series of 204 patients treated with the wrist in palmar flexion, neutral, or dorsiflexion that in those without comminution, wrist position did not change the risk of displacement. However, with comminution, dorsiflexed wrists demonstrated less risk for late displacement. In fractures with dorsal comminution, palmar- and neutral-positioned wrists lost 8 degrees of tilt and had 4 to 6 mm of shortening, whereas dorsiflexed wrists lost 2 degrees of tilt and 2 mm of shortening. It should be cautioned that these results were culled at 10 days with a commentary that “little difference was found between the 10-day and final follow-up films.” Functional results were better in all fractures with the wrist in extension. Significant amounts of volar flexion risk median nerve injury and limit flexor tendon excursion. Therefore, until further studies confirm Gupta’s results, we recommend a short-arm cast with the wrist neutral to slightly palmar-flexed and pronation and supination permitted.

Treatment When Reduction Is Lost

Three papers offer some guidelines about the limited usefulness of remanipulation. In the elderly, McQueen and associates found that of 28 patients with loss of reduction who were remanipulated, only 10 had a final result that suggested that remanipulation was beneficial; the others were the same or worse. In patients under 60 years of age, the authors found that 6 of 22 had no benefit or were worse after remanipulation.

It is interesting that subsequent work by McQueen and colleagues demonstrated no difference in functional outcome at 1 year of re-displaced fractures treated operatively with open reduction and internal fixation (ORIF) with Kirschner wires (K wires) and iliac crest bone graft compared with remanipulation and plaster cast or external fixation. There were, however, improved radiologic results with ORIF (3 degrees volar tilt for ORIF versus 13 degrees dorsal tilt for casting and 5 to 8 degrees dorsal tilt for external fixation). Based on these data, it appears that a high risk of loss of reduction exists if the first reduction and casting are unable to hold the position.

Length of Time to Follow Up for Loss of Reduction

Patients typically lose some reduction throughout the first 3 weeks of their cast treatment. Therefore, they should be followed up weekly for a minimum of 3 weeks to assess for loss of reduction.

Length of Time for Immobilization

Most studies of conservative treatment of distal radius fractures provide immobilization for 5 to 6 weeks. Given that there is a poor correlation between the type of immobilization and the final anatomic results and also that there does not appear to be loss of reduction after 4 weeks, one might suggest that a removable splint would likely be adequate at that point. However, there are no rigorous data yet to support this aggressive mobilization. Obviously, risks factors for instability may lead one to treat some fractures more or less cautiously.

What Outcomes Can Be Expected?

Digit stiffness can set in quickly, particularly in the elderly. The cast or splint should not extend distal to the distal palmar crease, the site of metacarpophalangeal (MCP) joint flexion ( Fig. 8-3 A and B). If careful attention is not paid to this, it is particularly easy to extend the cast past the metacarpal joint of the small finger. Patients are also encouraged to perform the six-pack exercises popularized by Dobyns and Linscheid at least three times per day.

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