Restoration of the main radiographic distal radial parameters has long been a focus of treatment in closed versus open management of distal radial fractures (DRFs).
Commonly used radiographic predictors for assessing adequate anatomic restoration include radial inclination, sagittal tilt (dorsal and volar), radial shortening, as well as intraarticular incongruity.
In review of the literature, radial height and articular incongruity have the most significant effect on patient-reported outcome measures (PROMs).
In particular, radial height loss of greater than 5–6 mm and articular incongruity > 2 mm is predictive of worse PROMs.
Radial inclination and sagittal tilt, while important to restore do not impact PROMs as significantly.
A 63-year-old active female physiotherapist falls from standing and presents to the emergency department with a moderately displaced extra-articular distal radius fracture. On postreduction radiographs, the dorsal tilt is neutral, radial inclination is 15 degrees and the distal radius is 5 mmshortened ( Fig. 1 ). She strongly requests “anatomic reduction” and fixation as she fears the slightest malunion may jeopardize her function. Opting for shared decision-making, the main question arises: What radiographic parameters are most predictive of patient-reported outcomes?
Importance of the Problem
Distal radius fractures (DRFs) are one of the more common musculoskeletal injuries that present to the emergency department or urgent care. Deciding how to manage a DRF therefore has implications with respect to patient function. Displaced, comminuted intraarticular DRFs are challenging injuries to treat with closed management, prone to collapse or re-displacement, and are often indicated for open reduction and internal fixation.
One of the first attempts to evaluate the functional outcomes of dorsally displaced DRFs was by Gartland and Werley in 1951. They concluded that the degree of comminution was directly proportional to the development of posttraumatic arthritis. However, despite incomplete reduction, satisfactory functional results were obtained in 68.3% of the series over 1 year of follow-up.
Since this study, predicting the successful return to function and elimination of pain has been studied in the literature by several papers. Commonly used radiographic predictors for assessing adequate anatomic restoration radial inclination, sagittal tilt (dorsal and volar), radial shortening, as well as intraarticular incongruity.
To what extent do radiographic parameters of radial inclination, radial height, dorsal tilt, and articular incongruity predict patient-reported outcome measures (PROMs)?
Despite the fact that radiographic parameters influence treatment paradigms to a large extent and are widely used as core evaluation tool, there remains lacking consensus on which radiographic parameters have the greatest impact on PROMs.
Finding the Evidence
Pubmed searches using keywords such as “distal radius patient-reported outcomes,” “outcomes after distal radius fracture,” “postoperative outcomes after distal radius fractures,” “radiographic parameters of distal radius fractures,” “volar tilt and distal radius fractures,” “radial inclination and distal radius fractures,” “articular incongruity and distal radius fractures,” “radial shortening and distal radius fractures.” Articles were excluded if not written in English.
Quality of the Evidence
Level I: 1
Level II: 5
Level III: 31
Level IV: 3
PROMs are tools that have been developed to identify and objectify patient satisfaction and function with respect to a particular injury. Patient outcomes include visual analog scale pain scores (VAS), patient satisfaction scores, return to work, and functional outcomes.
The most reliable and valid outcome measures reported for hand and wrist trauma are the disabilities of the arm, shoulder, and hand outcome (DASH) as well as the patient-rated wrist evaluation (PRWE). The DASH was designed for patients to briefly define symptoms and functional status. The PRWE was first published in 1998 by J.C. MacDermid as a result of the study of the International Wrist Investigators Group and was designed to measure pain and disability experienced by patients.
Several variables have been cited as important to restore functional and painless range of motion and grip strength. If radiologic parameters are predictive with respect to patient-reported outcomes, then restoration of all radiologic parameters as close to anatomically possible would ensure optimal patient outcomes.
In order to objectively measure the key radiologic parameters of a distal radius, standardized radiographs (including posterior-anterior and lateral views) must be obtained in the perioperative or conservative treatment setting ( Box 1 ).
Lateral and lateral 10 degree projection
Distal radial ulnar joint (DRUJ) view
In order to accurately measure the radiologic parameters, standardized radiographs must be performed. The posteroanterior requires the shoulder in 90 degrees of abduction, the elbow in 90 degrees of flexion and the wrist and forearm in neutral. For a lateral radiograph, the shoulder is fully adducted and the hand must be turned to lie in the same plane as the humerus. The pisiform should overlap the distal pole of the scaphoid. To obtain the tilted view, the forearm can be tilted 10 degrees to obtain a better view of the joint. For a DRUJ view, the wrist is in similar position as the PA view but the volar and dorsal cortex of the sigmoid notch should overlap.
Predicting outcomes from DRF radiographic assessment ( Box 2 ) can be done in two segments: evaluating the injury and prereduction films versus evaluating the posttreatment films (closed or open).
The normal radiographic parameters for the distal radius include an average volar tilt of 10–12 degrees, a radial inclination of 23 degrees, and a radial length of 12 mm. The tear drop angle measures approximately 70 degrees on the lateral radiograph of the distal radius.
This chapter is largely focused on radiographic assessment posttreatment but it is worth noting that Lafontaine’s criteria of dorsal displacement greater than 20 degrees, dorsal comminution, intraarticular fracture, associated ulnar styloid fracture as well as age greater than 60 years suggest worse anatomic and radiographic results with an increasing number of these factors present. However, Lafontaine’s series did not evaluate functional or subjective outcomes, only the anatomic parameters.
Evaluating prereduction parameters associated with patient outcomes, radial shortening, and severity of injury were associated with 6 month PRWE scores. When evaluating the 1 year PRWE scores, Grewal et al. did not identify any correlation with prereduction radiographic measurements: dorsal angulation (average 11 ± 17.5), ulnar variance (1.1 ± 2.3) or radial inclination (18.9 ± 7.1).
The radial inclination parameter has been evaluated by several authors going back to Mason’s fracture investigation in 1953. Mason found that in a subset of patients with both clinical dysfunction and pain, patients demonstrated loss of radial inclination. The loss of radial inclination of the distal radial fragment can lead to altered DRUJ kinematics and noticeable arthritic changes.
Gartland et al. noted in their seminal series of 60 DRFs treated with closed reduction that radial inclination was markedly varied after immobilization from 13 to 30 degrees. Despite reduction of the deviated radial fragment, there was a tendency to re-displace by follow-up examination. The authors do make note of the fact that radial inclination changes are associated with a rotation of the distal radial fragment into supination which can challenge the tension of the TFCC. However, little effect on functional outcome was noted overall.
Wilcke et al. found in series of 78 DRFs treated with closed reduction and immobilization, radial inclination greater than 10 degrees of the uninjured sided was associated with poorer DASH score and worse patient satisfaction.
Perugia et al. found in 51 patients treated with volar locking plates for DRFs, approximately 75% had restoration of radial inclination. They suggested that small variations do not effect final outcome at 3 years. Porter and Stockley found in their series of 115 patients with DRFs that when the radial inclination fell below 10 degrees, the grip strength was significantly reduced at 6 months and 2 years with a deficit measured at 33% and 30%, respectively.
Jenkins and Mintowt reviewed 58 patients and found a significant negative correlation between flattening of the radial inclination and patient grip strength. Further in agreement, Rubinovich concluded that a radial angle of less than 10 degrees resulted in a grip strength reduction. Additionally, patients with radial inclinations that exceeded normal values (16–28 degrees) led to unsatisfactory results in 50% of cases.
In 2005, Karnezis et al. demonstrated no correlation between loss of radial inclination and the PRWE score although the mean radial inclination was found to be 16 degrees and within a small variation to the normal range. In 2007, Kumar et al. found that patient outcomes, as measured by the MHQ and DASH were satisfactory even if the radiologic parameters including radial inclination were not. There was also a stronger inverse correlation in older age groups than younger age groups in their study.
Despite the variation in reported outcomes with altered radial inclination, subjective outcomes do not seem to be affected greatly by radial inclination. Of note, many patients that had worse functional or subjective outcomes with significant changes in radial inclination also had additional radiographic parameters that fell outside the normal range. Thus, in isolation, the impact of radial inclination is difficult to predict.
Loss of radial height, and by extension increased ulnar height and variance, is a well-studied radiographic parameter following DRFs treated by both closed and open techniques. One of the components of Gartland and Werley’s study, radial shortening is an often-examined radiographic metric to evaluate for successful management of a DRF by closed or open means. For patients with significant radial shortening during injury, regardless of postreduction improvements, there is a tendency toward re-shortening. Gartland and Werley found that significant shortening resulted in decreased ulnar deviation and that excellent functional results were obtained with average of 2.2 mm of shortening. On the contrary, Short et al. found that shortening of the radius altered force transmission and radiocarpal kinematics.
There is also concern that radial shortening will lead to altered DRUJ mechanics and ulnocarpal impingement. Consequently, ulnar-sided wrist pain after closed and open management of DRFs with incomplete restoration of radial height has been studied.
The degree to which shortening impairs function has been found to be proportionate to the amount of shortening. Fujii et al. found in their review of 22 elderly patients treated with closed reduction or open reduction and percutaneous pinning, functional outcome was affected when shortening was greater than 6 mm. However, 4 mm or less of shortening did not affect patient outcomes especially over 60 years of age.
However, Aro and Koivunen found that even minor shortening of the radius in patients 55 years and older could lead to unsatisfactory outcomes. Patients that had between 3 and 5 mm of shortening had significant disability according to the demerit score which evaluated functional as well as subjective outcomes. They also noted that there was no increased disability for patients that also had concomitant malalignment of the radial inclination or tilt in addition suggesting that radial shortening was the most important parameter to correct.
Wilcke et al. found that there was a distinction between 2 mm of shortening and significant changes in the DASH. For patients with greater than 2 mm of shortening, the DASH score averaged 10 points higher and the VAS satisfaction score was lower. Jenkins et al. found a significant increase in wrist pain for patients that had approximately 4.7 mm or greater of shortening compared to patients who were wrist pain-free with an average shortening of 2.3 mm or less.
In older patients, Karnezis found that radial shortening up to 5 mm can be tolerated. However, permanent shortening was strongly associated with persistent wrist pain and higher PRWE pain subscores. On the other hand, Barton et al. in a review of 60 patients treated with closed reduction and pinning found and average shortening of 2.6 mm [0–8 mm] and that no association between PRWE score was found suggesting that patients, especially older individuals, with moderate shortening would not have worse subjective outcomes.
One of the most commonly assessed radiologic parameters for DRFs is the dorsal tilt. The parameter is often utilized to justify open reduction internal fixation for significant variations in the parameter as well as the success of closed or open management in the posttreatment period. For fractures with greater degrees of dorsal tilt, especially with dorsal comminution, there is a high risk of re-displacement with closed reduction.
Dorsal angulation has been shown to alter the radiocarpal pressure concentrations as well as DRUJ kinematics. Acceptable ranges for dorsal angulation vary but largely include a range of 0–20 degrees.
In Gartland’s study of patients managed non-operatively with immobilization, patients that had excellent functional outcome had final follow up dorsal tilt of 0 degrees. However, there is no significant mention of patient reported outcome or satisfaction based on the degree of dorsal tilting. While greater than 10 degrees of dorsal tilting was associated with reduction in palmar flexion by 20 degrees, this does not seem to correlate with patient satisfaction. Tsukazaki et al. also found that dorsal tilt was the most important factor associated with loss of palmar flexion several years later in follow-up. Conversely, postreduction or intervention volar tilt that was increased beyond the average or contralateral seemed to lead to a decrease in wrist extension.
A few studies have evaluated the patient-reported outcomes. Wilcke et al. found that dorsal tilt that exceeded 15 degrees was associated with a poorer DASH score by approximately 10 points. Similarly, excessive dorsal tilt was found to correlate with worse VAS patient satisfaction scores. Kumar et al. found that there was a significant correlation between volar tilt and functional outcomes in younger individuals but not in older individuals. Despite many patients with poor radiologic results, there was a high proportion of patients with acceptable DASH and Michigan Hand Outcomes Questionnaire (MHQ) scores.
In 30 DRFs treated with closed reduction and percutaneous pinning and final volar tilt of 4.5 degrees [− 25 to 23 degrees], Karnezis et al. found that a permanent loss of volar tilt was associated with persisting wrist pain on the PRWE pain subscore which includes level of pain at rest as well as with various activities. They did not find a correlation with the functional outcome in the PRWE. Anzarut et al. reviewed 74 patients older than 50 years of age with non-operatively managed DRFs and divided the radiographic criteria as acceptable or unacceptable. Acceptable tilt was volar tilt < 20 degrees and dorsal tilt < 10 degrees, whereas unacceptable ranges were volar tilt > 20 degrees and dorsal tilting greater than 10 degrees. Forty-seven patients had acceptable radiographic parameters compared to 27. The authors found that radiographic reduction was not significantly associated with improved patient reported outcomes as measured by the DASH, SF-12, and patient satisfaction survey. They did demonstrate that 44% of patients with acceptable reductions were satisfied compared to 26% of patients with unacceptable outcomes.
Dorsal tilt does not appear to significant impact patient reported disability despite alteration in functional outcome. Functionally, dorsal tilt does appear to affect wrist arc of motion. Excessive volar tilt reduces wrist extension while excessive dorsal tilt reduces palmar flexion. Overall, abnormal values appear to be well tolerated unless they alter the distal radial ulnar joint mechanics.
Articular Step-Off and Incongruity
Articular step-off following closed or open treatment of DRFs has recently garnered significant attention following Jupiter’s classic article on measuring incongruity. The implications of articular incongruity include radiocarpal arthrosis and long-term arthritis. In their series, only 43% of patients had an excellent or good result with development of posttraumatic arthritis. No development of secondary arthritic changes were discovered when articular step-off was less than 1 mm in a separate study by Fernandez and Geissler.
While the degree of acceptable articular step-off has been challenged, as implant fixation improves and adjunct treatments such as arthroscopic-assisted reductions evolved, anatomic reduction of the articular surface remains an important goal and radiographic parameter.
Synn et al. evaluated four subjective assessment measures including the DASH and PRWE and found no relationship between subjective outcome and radiographic displacement with respect to articular step-off or articular gapping in patients older than 55 years of age.
In a retrospective study, Perugia et al. found that articular step-off was present in over 1/3 of patients with DRFs treated with a volar plate. The step-off was recorded as either greater than or less than 2 mm on a standard radiographs. However, they did not find correlation with articular step-off and worsening DASH scores.
Karnezis et al. found in their prospective study of 30 consecutive DRFs treated with closed reduction and percutaneous pinning, the presence of > 1 mm of articular step-off correlated with loss of dorsiflexion as well as worsening PRWE scores at 1 year.
Mehta et al. found in arthroscopic-assisted reductions and pinning of DRFs that there was a direct correlation between the size of the step-off and the development of wrist pain postoperatively. For patients with no step-off, VAS pain scores greater than 2 were found in 18% versus 38% with greater than 1 mm of step-off and 100% with > 2 mm.
Forward et al. published their results on younger patients (less than 40 years old at time of injury) with malunited DRFs with a mean follow-up time of 38 years. Nearly 70% had evidence of posttraumatic arthritis. However, their DASH scores were not dissimilar from population norms and overall pain was not significantly different to the contralateral wrist.
Similarly, Goldfarb et al. found that while radiocarpal arthrosis worsened over time after intraarticular fractures of the distal radius, patients maintained high function as longer term follow-up. No correlation between degree of arthrosis and the upper extremity function at average of 15 years.
One challenge with articular incongruity and step-off is accurate measurement. Because of poor inter and intraobserver agreement for measuring the degree of step-off on plain films, CT scans are recommended for more accurate measurement compared to standard radiographic assessment.
An important subparameter of the articular evaluation is the tear drop angle. On the lateral 10 degree projection, this parameter is easier to measure than articular incongruity. These parameters should be restored as variations in congruity.
The tear drop angle, which normally measures around 70 degrees, is the outline of the volar rim of the lunate face. The lunate facet is a major weight-bearing column of the distal radius and can determine articular incongruity and the direction of carpal instability.
Loss of the tear drop angle between the fractured and uninjured wrist was seen to lead to significant reduction in grip strength and worse DASH scores.
Patient satisfaction and pain relief are paramount in closed or open management of DRFs. While it is important to restore the native anatomy and approximate normal radiographic parameters, patients do tolerate incomplete restoration of these parameters and loss of some functionality without compromising satisfaction, especially in the elderly.
Assigning significance and causality to any one particular parameter is challenging. When viewed in combination, dorsal angulation, radial height, and radial inclination only accounted for 11% of the variability of clinical outcomes for displaced DRFs managed non-operatively as measured by VAS Pain, Q-DASH, PRWE, and Global Wrist Outcome Score (GWOS). Thus, less tangible factors such as psychosocial determinants play a far greater role in PROMs than restoration of radiographic parameters.