Up to two-thirds of distal radius fractures re-displace after initial reduction or from a minimally displaced position at presentation.
Increasing age and the presence of comminution, particularly dorsal, are the most commonly significant predictors of secondary displacement.
Other factors proposed to increase displacement risk are female gender, as well as dorsal tilt > 5 degrees, ulnar variance > 0 mm, loss of radial inclination, and increasing radial shortening on initial trauma radiographs, as well as the absence of volar cortical continuity (the “volar hook”) on postreduction radiographs.
A 65-year-old woman falls on an outstretched hand whilst gardening, sustaining a right distal radius fracture. She is right hand-dominant and works as a shop assistant. Fig. 1 A and B demonstrate her presentation radiographs. Fig. 2 A and B are her satisfactory postreduction radiographs following manipulation under regional anesthesia.
Which aspects of this case are concerning regarding the risk of secondary displacement?
How would this influence decision-making in terms of when to follow her up in clinic?
The same patient is seen in the out-patient department 8 days postreduction. Fig. 3 A and B show her repeat radiographs.
What are the available management options for this patient and how would a definitive decision be made?
Importance of the Problem
This chapter examines factors that result in an unstable fracture that subsequently displaces. The literature suggests that anything from 10% to 62% of distal radius fractures (DRFs) become displaced, either after being initially minimally displaced or after early displacement followed by an initial satisfactory reduction. Exact management strategies vary between institutions, but in many centers conservative management with casting forms the mainstay of treatment for undisplaced and minimally displaced fractures. Fractures that are initially displaced can undergo closed reduction and casting. Patients require clinic follow-up to monitor for subsequent fracture displacement, and this most frequently occurs within the first 2 weeks of injury. If loss of position does occur, there needs to be a decision as to whether the new position is felt to be acceptable, considering important patient-related factors including comorbidities and preinjury activity levels. If unacceptable, treatment options can then include re-manipulation and casting, percutaneous fixation with Kirschner wires, plate fixation or external fixation. As the time from initial injury increases, achieving a satisfactory reduction can be more technically challenging and time consuming, especially with closed techniques and poorer bone quality. The ability to predict subsequent fracture displacement would avoid this and allow patients to begin rehabilitation as soon as is possible.
Which injury characteristics predict fracture instability and secondary displacement in a distal radius fracture that is being managed conservatively?
Historically, Lafontaine’s criteria of dorsal tilt (referred to as angulation in the original paper) of more than 20 degrees, dorsal comminution, intraarticular radiocarpal fracture, associated ulnar fracture and age of over 60 years have been the most widely accepted predictors of secondary displacement. It is acknowledged that displacement results in inferior outcomes in young active patients, although some studies have demonstrated that this may not be the case in older lower demand patients. There is evidence to suggest that radiological parameters correlate poorly with functional and patient-reported outcomes. As with any orthopedic procedure, the risks of the proposed intervention must be considered against the perceived benefits. Decision making as to whether operative or nonoperative management is selected in the presence of a displaced fracture is highly dependent on patient factors, such as functional demand and medical comorbidities.
Finding the Evidence
A literature search was carried out using the terms “distal” and “radius fractures” plus “instability” and subsequently plus “unstable” and “displacement.” Titles and abstracts were reviewed, and articles not written in English or carried out in those under the age of 16 were excluded. Databases searched included the Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE. Bibliographies of suitable articles were also examined.
Quality of Evidence
Prospective cohort studies: 5
Systematic Reviews/Metaanalyses: 1
Systematic Reviews/Metaanalyses: 1
Retrospective comparative studies: 5
Zenke et al. prospectively studied 60 patients with a dorsally displaced distal radius fracture. Fractures were reduced with local anesthetic hematoma block before immobilization in a sugar-tong (above-elbow) splint. Seventy-eight percent were female and the mean age was 72 years (range 55–96). By AO/OTA classification, patients with A2, A3, C1, C2, and C3 were included, with more than half of patients falling into the A3 category. The authors classified fractures into three types based on the volar cortex on the lateral postreduction radiograph. Fractures were classed as “intramedullary” when the volar cortex of the distal fragment was translated and impacted dorsally to the proximal part (in the medulla), “anatomical” when the proximal and distal parts of the volar cortex met, and “extramedullary” when the volar cortex of the distal fragment was translated and impacted volarly to the proximal fragment. They evaluated subsequent displacement based on volar tilt, radial inclination, and ulnar variation. There was a loss of volar tilt and radial inclination correction in all three groups, but no significant differences between them. However, although there was a loss of ulnar variance correction in all three groups, this was significantly greater in the intramedullary group ( P = .012). The authors suggest that, based on this, conservative management should be avoided in patients in the intramedullary group. However, given the small sample size, this classification can only be used as one factor to aid in the prediction of secondary displacement.
Jung et al. prospectively studied 132 displaced distal radius fractures after closed reduction and stabilization with a sugar-tong splint followed by a below-elbow cast. Seventy-eight percent were female and the mean age was 58 years (range 21–89). By AO/OTA classification, 90 were type A, 33 type B, and 9 type C. Secondary displacement was divided into early (occurring before the first follow-up visit at 1 week) and late (occurring after 1 week). Early displacement was significantly associated with the presence of initial displacement ( P < .001). Initial acceptable alignment was defined as dorsal tilt < 10 degrees, volar tilt 15 ± 10 degrees, radial inclination ≥ 17 degrees and translation < 2.0 mm. It is not clear from the study if the volar tilt includes, or is in addition to, the normal anatomical volar tilt. Late secondary displacement was only significantly associated with age ( P = .005).
Wadsten et al. conducted a prospective multicenter study involving 398 fractures. The mean age was 56 years (range 15–74) and 78% were female. Minimally displaced fractures were casted in a dorso-radial slab and displaced fractures were reduced under hematoma block or intravenous regional anesthesia and similarly casted. The Buttazzoni classification ( Table 1 ), which primarily focuses on comminution, formed the basis of the analysis. There was a significant difference in frequency of displacement between each type as the classification ascended ( P < .001), except for B2 versus B3 ( P = .92), with B1 least likely to displace and B4 most likely. A similar relationship was observed in relation to late displacement at 10–14 days postinjury. Many studies focus on dorsal or generalized comminution, whereas Wadsten and colleagues specified this as being dorsal or volar. The Buttazzoni classification does seem to be useful in risk stratification of secondary displacement, but in several of their analyses the B2 and B3 results did not concur with the overall trend of increased displacement risk as the classification progressed.
Tahrininian et al. conducted a prospective cohort study including 157 patients. The mean age was 51 years (20–86) and 68% were female. Displaced fractures were treated with 5 kg of finger-trap traction and then manual closed reduction under intravenous sedation followed by below-elbow casting. Fracture type was not classified. Patients were divided into two groups based on whether they maintained or lost the primary acceptable reduction. These groups were subsequently compared. Gender ( P = .13), presence of dorsal comminution ( P = .08) and the presence of ulna fracture ( P = .21) were not significantly associated with secondary displacement. The presence of an intraarticular fracture was significantly more likely in the group that maintained reduction ( P = .01), which contrasts with the general findings and consensus in the literature. Loss of radial height ( P < .001), loss of radial inclination ( P < .001) and age ( P < .001) were the most important factors in predicting secondary displacement after an initially satisfactory closed reduction. A receiver operating characteristic (ROC) curve was used to try and predict secondary displacement. A 6.5 mm loss of radial height (sensitivity 68.5% and specificity 81.5%) and 6.5 degrees loss of radial inclination (sensitivity 80.4% and specificity 67.7%) were felt to be the most appropriate cut-off values for likelihood of displacement. The contralateral uninjured wrist was evaluated radiographically to assess radial shortening and inclination.
Mackenney et al. prospectively recorded data on 4000 distal radius fractures. Seventy-nine percent of patients were female and the mean age was 64 (range 14–100). They divided instability into:
Early: displacement (or re-displacement following reduction) within 2 weeks of injury
Late: displacement at the time of union (6 weeks) but not before
Minimally displaced fractures were described as having dorsal tilt of ≤ 10 degrees and ulnar variance of < 3 mm. Displaced fractures had dorsal tilt of > 10 degrees and/or ulnar variance of > 3 mm. Carpal malalignment was defined as failure of the long axes of the radius and the capitate to intersect within the carpus ( Fig. 4 ). Metaphyseal comminution was judged qualitatively from the radiographs. Ten percent of minimally displaced fractures at presentation demonstrated early instability and this was significantly associated with age ( P < .001), comminution, dorsal tilt > 5 degrees ( P < .01) and ulnar variance > 0 mm ( P < .01). A total of 22% of minimally displaced fractures demonstrated late instability with patient age ( P < .001), the presence of comminution ( P < .01), the dorsal angle ( P < .001) and ulnar variance ( P < .001) being significant. Forty-three percent of fractures that were displaced at presentation went on to further early displacement. Age ( P < .001), ulnar variance at presentation ( P < .001) and comminution ( P < .01) were significantly associated. Overall, 47% of displaced fractures at presentation subsequently re-displaced, either early or late, with age ( P < .001), 1-week dorsal tilt ( P < .001) and ulnar variance ( P < .001) being significant. The authors also produced a formula to predict instability and carpal malalignment. This is referred to as “the McQueen equation” in subsequent literature. Mackenney et al. do provide further information to aid the prediction of secondary displacement, although in terms of age, they simply describe that the risk of displacement increases with age and do not further explain this. However, quantification of instability is suggested, e.g., early instability is 10 × more common in those over 80 years old than in those under 30 years of age.