Diagnosing the Malunited Distal Radius





Key Points





  • The diagnosis of a malunited distal radius fracture (DRF) must take into account both clinical symptoms and radiographic findings



  • Standard radiographs of both the affected and contralateral wrist are usually sufficient to diagnose distal radius malunions, but CT scans can provide additional information for complex deformities





Panel 1: Case Scenario


A 72-year-old, right hand dominant, retired male presents to your office with chronic left wrist pain and decreased range of motion after conservative management of a distal radius fracture 10 years prior. Radiographs show a “malunited, impacted, intraarticular fracture of the left distal radius with dorsal tilt and decreased height and inclination of the distal radial articular surface ( Fig. 1 ).” How would you proceed with your evaluation in order to identify a symptomatic malunion of his prior distal radius fracture?




Fig. 1


(A–C) AP, lateral, and oblique radiographs of the left (affected) and right (normal) wrist demonstrating a malunited, impacted, intraarticular fracture of the left distal radius with dorsal tilt and decreased height and inclination of the distal radial articular surface. Scapholunate widening with DISI deformity. Moderate radioscaphoid narrowing and scattered moderate degenerative arthritis.







Importance of the Problem


Distal radius fractures (DRFs) are among the most common fractures managed by trauma surgeons, accounting for approximately 17% of all fractures managed in an orthopedic trauma unit. Malunion is fairly common following a DRF, with reported malunion rates of 23.6% and 10.6% after closed reduction with casting and surgical management, respectively. Patients with symptomatic malunion after a DRF demonstrate persistent disability at 1 year, 2 years, and 12–14 years after fracture treatment. Malunited DRFs alter the biomechanics of the distal radioulnar joint (DRUJ) as well as the radiocarpal, ulnocarpal, and midcarpal articulations, which may accelerate degenerative changes and produce pain as well as functional impairment. Carefully planned corrective osteotomies can significantly improve the radiographic and functional outcomes in these patients, and, therefore, it is paramount to recognize and appropriately diagnose this condition.


Main Question


For all patients who have sustained DRFs, how is a symptomatic malalignment of the radius most accurately diagnosed, both clinically and radiologically?


Current Opinion


The diagnosis of symptomatic distal radius malunion requires both clinical symptoms in addition to radiographic abnormalities. While plain radiographs are sufficient to diagnosis most distal radius malunions, computed tomography (CT) scans are extremely useful to diagnose rotational malunions as well as aid in surgical planning of the corrective osteotomies.


Finding the Evidence


We provide below a list of search algorithms used to construct this chapter:




  • Cochrane search: “distal radius”



  • PUBMED (clinical queries: systematic reviews): “distal radius”



  • PUBMED (Medline): “distal radius” AND “malunion”



  • Bibliography review of the selected articles



  • Articles that were not in the English were excluded.



  • Articles involving anything other than human subjects were excluded.



Quality of the Evidence


Overall, there were no randomized control trials or other Level I evidence that addressed the primary question. However, there were multiple articles of varying levels of evidence that are relevant to the main question. They are stratified into the following levels of evidence:




  • Level II: 4



  • Level III: 2



  • Level IV: 1



  • Level V: 8



Findings


Evidence From Level II Studies


There were four studies that evaluated patient-reported outcomes in those with malunion of DRFs. Grewal and MacDermid prospectively evaluated 216 patients with extraarticular DRFs with the goal of determining if individual radiographic parameters (dorsal angulation, radial inclination, and radial shortening) and the overall acceptability of alignment of the healed DRF influenced patient-reported pain and disability at 1 year, as measured by standardized patient-rated pain and disability scores [Patient-Rated Wrist Evaluation (PRWE) and Disabilities of Arm, Shoulder, and Hand (DASH)]. Alignment was deemed “unacceptable” if dorsal angulation was > 10 degrees, if radial inclination was < 15 degrees, or if there was ≥ 3 mm of ulnar positive variance. They found that in patients younger than 65 years of age, overall malalignment was associated with significantly higher pain and disability scores at 1 year. When examining radiographic parameters in isolation, radial inclination and radial shortening were associated with significantly higher PRWE scores and radial shortening was associated with a significantly higher DASH score (with dorsal angulation and radial inclination trending toward significance). In patients greater than 65 years of age, the presence of malalignment did not influence patient-reported outcomes.


Atroshi’s group in Sweden consecutively enrolled patients 18–65 years old who presented over a 15 months period with acute, extraarticular or intraarticular DRFs and were subsequently treated with casting, closed reduction and casting, or closed reduction and percutaneous fixation; those who underwent open reduction and internal fixation were excluded. These patients were prospectively enrolled and longitudinally followed with DASH scores and radiographs. Malunion was defined using the same criteria as describe above. At 1 year, 2 years, and 12–14 years follow-up, radiographic malunion was associated with higher arm-related disability. Specifically at 1 year, dorsal tilt and ulnar variance were found to significantly affect DASH score, while radial inclination had no significant effect. Patients with malunion involving dorsal tilt and/or ulnar variance were significantly more likely to have higher disability compared to patients with no malunion. Patients with malunion involving only dorsal tilt or only ulnar variance had lower DASH scores than patients with combined malunion. Again at 2 years follow-up, patients with malunion involving ulnar variance and dorsal tilt had worse disability than patients with no malunion. At the time of extended 12–14 years follow-up, increased dorsal angulation, increased ulnar variance, and decreased radial inclination were associated with higher DASH scores. The relationship between the DASH score and the radiographic variables of dorsal tilt, ulnar variance, and radial inclination were analyzed as continuous variables which demonstrated significant associations between a higher DASH score at time of follow-up and increased ulnar variance, increased dorsal angulation, and decreased radial inclination. The authors advocate that patients with disability at 1 year after fracture and radiographic malunion with positive ulnar variance or substantial dorsal tilt should be considered for corrective osteotomy.


Evidence From Level III Studies


Miyake et al. sought to estimate the accuracy of distal radius malunion assessment by comparing standard radiographic measurements (volar/dorsal tilt, radial inclination, and ulnar variance) with those from CT obtained 3-dimensional methods in 20 dorsally tilted malunions. They found that radiographic evaluation of dorsal tilt was reasonably accurate, but the radiographic evaluation of radial inclination and height were less accurate. With regards to radial inclination, the absolute difference between evaluations using the 3D method and plain radiographs was up to 21 degrees (average 5.7 degrees). When assessing ulnar variance, 8/20 cases had a discrepancy of ≥ 2 mm. The authors concluded that standard radiographic evaluation of volar/dorsal tilt was likely reliable for surgical planning, but measurements of radial inclination and shortening deformities may benefit from CT.


Prommersberger et al. evaluated the rotational deformity of distal radius malunions. CT scans of both the normal and injured wrists were performed, and the radial torsion angle of both wrists was calculated. They found that 23/37 (62%), when compared to the uninjured wrist, demonstrated a rotational deformity. The supination deformity averaged 10 and 14 degrees in dorsally and volarly angulated malunions, respectively. The pronation deformity averaged 10 and 13 degrees in dorsally and volarly angulated malunions, respectively. The authors concluded that obtaining preoperative CT scans of both wrists may be helpful to identify a rotational malunion and to subsequently help plan the corrective osteotomy.


Evidence From Level IV Studies


Keizer et al. performed a systematic review evaluating outcomes of 3D virtual planning of corrective osteotomies for distal radius malunions. The authors highlighted the anatomic variability among individuals and importance of imaging the contralateral forearm for a standard reference. The authors also discussed the utility of obtaining a CT scan to better understand the anatomy of complex deformities and to identify rotational deformities. They concluded that 3D-planned corrective osteotomy significantly improves both radiographic and functional outcomes in distal radius malunion reconstruction.


Evidence From Level V Studies


Multiple authors agree that the diagnosis of a distal radius malunion must take into account clinical symptoms, physical exam findings, and radiographic parameters. The standard radiograph to evaluate the distal radius should include anteroposterior (AP), lateral, and oblique views of the affected wrist, with contralateral wrist films for comparison. CT scans with 3D reconstructions may be helpful, especially to assess for rotational deformities. Radiographs do not always correlate with symptoms, and therefore the symptoms and resulting functional limitations should guide management rather than radiographic appearance alone.


Graham proposed four radiographic criteria to assess the adequacy of healing of a DRF. Acceptable measurements were radial inclination ≥ 15 degrees, volar tilt < 20 degrees, or dorsal tilt < 15 degrees, radial shortening < 5 mm at the DRUJ, and intraarticular incongruity < 2 mm. Haase and Chung, based upon their experience, expert opinion, and review of the literature, proposed the following criteria to radiographically define distal radius malunions: radial inclination < 10 degrees, volar tilt > 20 degrees, or dorsal tilt > 20 degrees, radial height < 10 mm, ulnar variance > 2 +, and intraarticular step or gap > 2 mm. Slagel et al. based upon their review of the literature and expert opinion, defined a malunited distal radius fracture as follows: dorsal tilt > 20 degrees, displaced fractures with carpal malalignment (> 15 degrees of dorsal angulation of lunate on lateral radiographs), incongruity of the DRUJ, and > 5 mm of ulnar variance.


There are numerous biomechanical changes that may result from malunion of DRFs. The resulting clinical sequelae are numerous and include pain (radiocarpal, midcarpal, or distal radioulnar), decreased range of motion (flexion/extension and pronation/supination), cosmetic deformity, and decreased grip strength.


Recommendation


In patients with an intraarticular displaced distal radius fracture, evidence suggests:



Conclusion


The diagnosis of a symptomatic distal radius malunion begins with a thorough physical exam. Exam findings of a distal radius malunion can include signs or symptoms of radiocarpal, intercarpal, and distal radioulnar joint arthritis and instability as well as decreased range of motion and grip strength. AP, lateral, and oblique radiographs of the affected wrist should be compared to radiographs of the contralateral wrist and to normative values, noting changes in volar tilt, radial inclination/height, and ulnar variance. CT scans can be obtained for a more detailed evaluation and for surgical planning.


Mar 15, 2021 | Posted by in RHEUMATOLOGY | Comments Off on Diagnosing the Malunited Distal Radius
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