Sat., 10/6/12 Upper Extremity Injuries, PAPER #82, 10:16 am OTA-2012
Ulnar Variance as a Predictor of Persistent Instability Following Galeazzi Fracture-Dislocations
Richelle C. Takemoto, MD1; Igor Immerman, MD1; Michelle Sugi, MD2;
Nirmal C. Tejwani, MD1; Kenneth A. Egol, MD1;
1NYU Hospital for Joint Diseases, New York, New York, USA
2LAC-USC Medical Center, Los Angeles, California, USA
Background/Purpose: Currently, only the distance from the radiocarpal joint (RCJ) to the fracture has been identified as a predictor of distal radioulnar joint (DRUJ) instability in association with a radial shaft fracture. However, this measurement is not proportionalized to the differences in the length of the radial shaft. The purpose of this study was twofold: (1) evaluate the RCJ to fracture distance proportional to the length of the radial shaft and (2) to identify other injury and radiographic predictors of DRUJ instability associated with these fractures.
Methods: 50 patients who sustained 50 fractures of the radial shaft were identified and followed for a minimum of 6 months after surgery between 2003 and 2009. All radius fractures were treated with plate and screw fixation. Persistent DRUJ instability was defined as continued clinical instability following surgical fixation of the radial shaft. Medical records and radiographs were reviewed retrospectively. Demographic data, mechanism of injury, normalized preoperative injury ulnar variance, and the ratio of the distance from the RCJ to the fracture over the entire length of the radius were analyzed using the Fisher exact test and Student t test.
Results: 50 patients had persistent DRUJ instability following fixation of the radius fracture and were addressed operatively. As a proportion of radial length, the distance from the RCJ to the fracture line did not significantly differ between those with persistent DRUJ instability (0.37; range, 0.19-0.70; standard deviation [SD] = 0.12) and those without (0.34; range, 0.14-0.62; SD = 0.098) (P = 0.34). The mean normalized injury-induced ulnar variance in the group with DRUJ instability was 5.5 mm (median, 4; range, 2-12 mm; SD = 3.2). The mean normalized preoperative injury ulnar variance in the group without DRUJ instability was 3.8 mm (median, 2.5; range, 0-11 mm; SD = 3.5). Only 4 of 20 patients (20%) with DRUJ instability had a normal ulnar variance (–2 mm to +2 mm) while 15 of 30 patients (50%) without DRUJ instability had a normal ulnar variance. This difference was statistically significant (P = 0.041). There were no significant differences with respect to age, gender, presence of polytrauma, or the location of the fracture along the radius. Complications included one fracture nonunion and one peri-implant fracture at 9 months postoperatively.
Conclusion: In the setting of an isolated radial shaft fracture, injury-induced ulnar variance (as measured on initial injury radiographs) greater than +2 mm or less than –2 mm was associated with a greater likelihood of DRUJ instability following fracture fixation. Neither the absolute distance nor the ratio of distance from the RCJ to the fracture was predictive of persistent DRUJ instability.
Alphabetical Disclosure Listing (808K PDF)
• The FDA has not cleared this drug and/or medical device for the use described in this presentation (i.e., the drug or medical device is being discussed for an “off label” use). ◆FDA information not available at time of printing. Δ OTA Grant.