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Does malunion in multiple planes predict worse functional outcomes in distal radial fractures?

Cantlon, Matthew B. MD; Marcano, Alejandro I. MD; Lee, James BS; Egol, Kenneth A. MD

doi: 10.1097/BCO.0000000000000398
RESIDENT RESEARCH
Free

Background: The objective of this study was to investigate whether the total number of radiographic malalignments after distal radial fracture was associated with poor clinical outcome.

Methods: Over a 7-year period, 382 patients who sustained a distal radial fracture were enrolled in a prospectively collected database and met our inclusion criteria. Patients were followed for a mean of 11 mo. Radiographs were taken and analyzed at each follow-up interval. Patients were divided in three groups, those with normal radiographic alignment (group 1), those with one abnormal measurement (group 2), and those with two or more abnormal measurements (group 3). Each patient was assessed for the Disabilities of the Arm Shoulder and Hand (DASH) and Short Form-36 (SF36) clinical outcome scores, along with functional parameters.

Results: Thirty-four percent of patients had at least one abnormal radiographic measurement after initial reduction, 21% at short-term, and 24% at long-term follow-up. The long-term DASH was low (18.17 and 12.12 in groups 2 and 3, respectively) and the SF36 was correspondingly high (77.36 and 80.45 in groups 2 and 3, respectively). No individual radiographic measurement of wrist deformity or a combination of these was significantly correlated to any of the clinical outcome scores or functional parameters.

Conclusions: Our data confirm reports from previous studies that no single radiographic measurement was correlated with clinical or functional outcomes. Moreover, if analyzed in combination, malalignment in multiple planes did not result in a higher association with worse outcomes.

Department of Orthopaedic Surgery, Hospital for Joint Diseases, NYU Langone Medical Center, New York, NY

Financial Disclosures: The authors have no financial disclosures and report no conflicts of interest in regard to this work.

Correspondence to Kenneth A. Egol, MD, Department of Orthopaedic Surgery, Hospital for Joint Diseases, NYU Langone Medical Center, 301 East 17th street, 14th Floor, New York, NY 10003 Tel: +212-598-3889; fax: +212-598-6015; e-mail: Kenneth.Egol@nyumc.org.

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INTRODUCTION

The most common complication of distal radial fractures is malunion,1,2 and if symptomatic it could potentially require a corrective osteotomy.1,3 There is a lack of consensus among studies correlating the amount of radiographic deformity of the distal radius to clinical or functional outcomes, and no clear relationship has been demonstrated to date.4 However, there is also no agreement on what constitutes an acceptable radiographic position, which should be defined as one that would predict a satisfactory functional result.5

Several measurements are used to assess the anatomy of the distal radius, including radial inclination, radial height, palmar tilt, and ulnar variance. Dorsal tilt and loss of radial inclination have been correlated with reduction of grip strength,6 while the most important factor affecting functional outcomes is reportedly radial length followed by dorsal tilt.7 When analyzing patient-reported outcome questionnaires such as the Disabilities of the Arm, Shoulder and Hand (DASH) survey, some authors have reported that malalignment is not correlated with poor outcomes.8 while others have reported that DASH scores are worse in patients with a combination of dorsal tilt and ulnar variance.9

The majority of studies that correlate abnormal radiographic measurements to poor outcomes in distal radial fractures analyzed only a single parameter, while few analyzed multiple parameters occurring in combination. The objective of this study was to investigate whether an association exists between distal radial malunion in more than one plane and poor clinical outcomes. Our hypothesis was that the sum total amount of distal radial malunion would not be correlated with worse outcomes.

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MATERIALS AND METHODS

Over a 7-year period, a total of 627 consecutive distal radial fractures treated by members of the Trauma and Hand divisions at our institution were prospectively enrolled in a database. We excluded 24 patients who sustained bilateral distal radial fractures and 23 patients with incomplete initial information. Of the remaining 580 patients, 281 patients were treated operatively, and 299 were treated nonoperatively. One hundred and ninety-eight patients had missing data and were excluded from analysis. The remaining 382 patients are included in this report.

This study was approved by our Institutional Review Board and written informed consent was obtained from each patient at the time of enrollment. All procedures followed were in accordance with the ethical standards of the Institutional Review Boards of the participant institution and with the Helsinki Declaration of 1975, as revised in 2000 and 2008. At initial presentation, all displaced fractures underwent closed reduction and immobilization with a sugar-tong splint. Baseline demographic data, injury information, and baseline functional scores on the DASH and the Short Form-36 version 2 (SF36) questionnaires were recorded. The DASH is a validated patient-reported outcome questionnaire that measures upper extremity disability on the basis of physical function and symptoms that results in a score ranging from 0 points, representing no disability, to 100 points, representing maximum disability.10 The SF36 survey is another validated questionnaire that yields a profile of functional health and well-being scores as well as psychometrically-based physical and mental health summary measures in a scale ranging from 0 points, representing worst quality of life, to 100 points, representing best quality of life.11 A complete history and physical examination were performed. Standard radiographs of the affected and contralateral wrists were taken at the time of the initial injury. Fractures were classified according to the system of the Orthopaedic Trauma Association (OTA). Measurements of radial inclination, radial height, palmar tilt, ulnar variance, and articular step-off were recorded from each radiograph.

Surgery was indicated in patients with an open fracture or those with an inherently unstable fracture pattern, including a shear fracture, a fracture-dislocation of the wrist, or, in general, if at least three of the following criteria were present as discussed by Lafontaine et al.:12 initial dorsal angulation of >20 degrees, initial shortening of >5 mm, >50% dorsal comminution, an intraarticular fracture, an associated ulnar fracture, or an age of more than 60 yr. These patients were treated with either a volar locked plate or bridging external fixator with supplemental Kirschner wire fixation (usually two or three wires).

All patients, both operative and nonoperative, were followed by their treating surgeon, with follow-up at 2 and 6 wk and at 3, 6, and 12 mo. All patients participated in a formal outpatient therapy program, which emphasized active and passive range of finger motion, wrist motion (if able), and forearm motion.

At each assessment, an independent researcher measured the range of movement of the wrist and fingers using a goniometer. Patient-reported functional outcome measures were completed (DASH and SF36 questionnaires). Pain was rated by a 10-point visual analogue scale (0, no pain; 10, severe pain). Grip strength was obtained with a dynamometer at each visit and on the uninjured side at 3 mo for comparison. Radiographs were assessed at each visit for fracture union, loss of reduction or malunion, and development of arthritis. Measurements of radial inclination, radial height, tilt, ulnar variance, and articular step-off were made on each radiograph by a trained researcher under the direction of the treating surgeon (Figure 1). Acceptable radiographic measurements were defined from the literature and included: radial inclination of >15 degrees, radial height of >5 mm, tilt of −10 degrees to +20 degrees, ulnar variance of −2 mm to +1 mm and articular step-off of <1 mm.9,13 Arthritic change or its advancement was noted if present, with use of the system described by Knirk and Jupiter.14

FIGURE 1

FIGURE 1

Patients were divided into three groups based on radiographic measurements obtained at the short-term follow-up interval (6-week follow up visit): group 1 included those with radiographic measurements within normal limits; group 2 included those with one unacceptable radiographic parameter; and group 3 included those with two or more unacceptable radiographic parameters.

A multivariate analysis of variance (MANOVA) was performed to find differences between the three groups and univariate post hoc analyses were performed to evaluate differences in further detail. Differences in demographic characteristics were evaluated using the chi-square test for categorical variables such as sex, hand dominance, fracture pattern, and the Student t-test for continuous variables such as age. We used Mann Whitney U tests to assess differences between groups in DASH and SF36 scores at the long-term follow-up (12 mo visit) as well as differences in range of motion and radiographic measurements. Individual radiographic measurements plus the total number of abnormal measurements were correlated with clinical outcome scores and functional parameters using Spearman’s correlation coefficient. A P value of <0.05 was considered significant.

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RESULTS

Three hundred and eighty-two patients met the inclusion criteria and were analyzed in this study. Group 1 had 303 patients, group 2 had 63 patients, and group 3 had 16 patients. There were no differences among mean age across the three groups (52.0 yr, group 1; 55.4 yr, group 2; 52.8 yr, group 3). No other demographic differences (sex, race), type of accident, or dominant hand fracture were seen between the groups. No differences in baseline DASH scores were seen between the groups, indicating similar preinjury functional status. Fracture type distribution was similar between groups 2 and 3 but differed in group 1 compared with group 2 (P=0.015) and group 1 compared with group 3 (P=0.035) (Figure 2).

FIGURE 2

FIGURE 2

Patients were followed for a mean of 11 mo. Thirty-four percent (129 of 382) of patients had at least one abnormal radiographic measurement after initial reduction (IR), 21% (80 of 382) at short-term (ST) and 24% (92 of 382) at long-term (LT) follow-ups, no patients had abnormal measures for all five radiographic parameters. The most commonly observed deformity at ST was loss of radial inclination (13%; 50 of 382) followed by loss of palmar tilt (6%; 23 of 382).

There were no differences in reported pain between the groups at any time point. LT DASH was 12.89, 18.17, and 12.12 for groups 1, 2 and 3, respectively. No differences were found between groups. SF-36 scores at LT were 80.44, 77.36, and 80.45 for groups 1, 2 and 3, respectively. No differences were found between groups (Table 1).

TABLE 1

TABLE 1

Grip strength as a percentage of the contralateral side at LT was better in group 1 (79%) than group 2 (62%) (P=0.010); grip strength in group 3 (97%) was higher than groups 1 and 2.

When correlating variables, though several significant correlations were found, none of them were strong. Wrist extension (−0.2; P=0.004) and wrist supination (−0.198; P=0.005) at ST had weak negative correlations with the total number of abnormal radiographic measurements. Healing time also had a weak positive correlation (0.126; P=0.027), with total number of abnormal measurements. No long-term outcome measures were correlated with the total number of abnormal radiographic measurements.

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DISCUSSION

A reliable measure should aid in predicting the outcome of a given treatment and then be able to guide further treatment.4 With this in mind, radiographic measurements in distal radial fractures have yet to prove useful in predicting outcomes. Thus, considerable attention has been drawn towards the concern of whether it is clinically important to restore normal radiographic measurements after distal radial fractures.5,15,16 Biomechanical studies in cadavers have potentiated the importance of studying radiographic distal radial malunion measurements. One study showed that some parameters (i.e. radial shortening, decreased radial angle and dorsal tilt) caused some disturbance in wrist kinematics.17 Some studies have shown functional abnormalities after failure to restore normal radial anatomy.7,18 Controversy exists, however, as several recent studies have shown that there is no one specific radiographic parameter that strongly correlates with poorer functional outcomes after distal radial fracture.13,19–23 Furthermore, Finsen et al.24 performed a retrospective review of 260 patients at a mean of 6.3 yr after distal radial fracture and concluded that radiographic alignment has only minor influence on clinical outcome. Grewal and MacDermid8 performed a study of 216 patients with distal radial fractures and concluded that radiographic alignment became less important in terms of functional outcome with increasing age.

Brogren et al.9 prospectively evaluated 123 patients with distal radial fractures treated with closed reduction and casting and found that the mean change in DASH scores were greater for patients with malunions involving ulnar variance and dorsal tilt than for patients with no malunions or with either ulnar variance or dorsal tilt alone. This is in contrast to our data, which confirm reports from previous studies that no single radiographic measurement was correlated with clinical or functional outcomes. Moreover, if analyzed in combination, no number of combined abnormal radiographic measurements represented a higher association with worse outcomes. These data lead us to question the importance of detailed analysis of distal radial radiographic parameters.

Various limitations of our study exist. While the DASH is technically a measure of disability, we chose to use the DASH as a measure of functional outcome. One must take into account that while function and disability may be related, they may not be mutually exclusive. Group 3 had a relatively small number of patients and is underpowered for statistical analysis. Another limitation is the variation in radiographic parameters as measured at each visit. Differences in radiographic technique and human error could account for differences between groups. Finally, length of follow-up in this study is a limitation. It is possible that with longer-term follow-up, the posttraumatic arthritis noted at 1 yr could begin to impact function. Due to incomplete data within our database, the number of measurements of the contralateral uninjured wrist was not satisfactory enough to compare injured and uninjured limbs for each patient.

It appears from this data that no single or combination of radiographic measurement is correlated with impaired clinical or functional outcomes. These data lead us to question the importance of detailed analysis of distal radial radiographic parameters.

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Keywords:

distal radius; malunion; fracture; outcomes

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