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Symposium: Traumatic Elbow Instability and its Sequelae

Injury Patterns and Outcomes of Open Fractures of the Proximal Ulna Do Not Differ From Closed Fractures

Yi, Paul H. BA1,3,a; Weening, Alexander A. MD2; Shin, Sangmin R. MD1; Hussein, Khalil I. BA1; Tornetta, Paul 3rd MD1; Jawa, Andrew MD1

Author Information
Clinical Orthopaedics and Related Research: July 2014 - Volume 472 - Issue 7 - p 2100-2104
doi: 10.1007/s11999-014-3489-x
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Abstract

Introduction

Fractures of the proximal ulna are common [15], representing 21% of all fractures of the proximal forearm [8]. Although the injury characteristics and management of closed proximal ulna fractures have previously been well described [8, 14, 15], there is little evidence to guide management of open fractures.

Data on open fractures of the distal humerus may suggest that open elbow fractures are complex injuries associated with extensive soft tissue damage, higher infection rates, and greater stiffness when compared with closed fractures [3, 10]. However, epidemiological studies of proximal ulna fractures and open fractures in general suggest that open proximal ulna fractures present with relatively mild soft tissue injury [5, 8]. Few studies have directly assessed the injury characteristics and outcomes of open proximal ulna fractures or compared these measures with those of closed fractures.

Thus, the purpose of our study was to compare the (1) bony injury patterns; (2) ROM and frequency of union; and (3) postoperative complications between open and closed fractures of the proximal ulna.

Patients and Methods

After institutional review board approval, we retrospectively reviewed a consecutive series of 671 patients who presented with a fracture of the proximal ulna to three Level I trauma centers between January 1, 2002, and January 1, 2010. We identified 79 patients with an open fracture of the proximal ulna, defined as an AO/OTA Type 21-A, B, or C fracture of the proximal ulna (representing 12% of the overall population of proximal ulna fractures at these three trauma centers). Nineteen patients were excluded for the following reasons: younger than 18 years of age (one), open ulnohumeral fracture-dislocation (13), penetrating injury (four), and both younger than 18 years of age and penetrating injury (one). Therefore, 60 total patients (60 fractures) remained for potential matching (15 AO/OTA Type 21-A [extraarticular, 25%] and 45 Type 21-B or C [intraarticular, 75%]).

Injury Characteristics

The majority of open fractures (54 of 60 [90%]) were Gustilo and Anderson Type I or II injuries (Table 1). Fifty-four patients (90%) presented with a wound over the olecranon or posterior elbow, two with a wound over the lateral elbow (3%), one with a wound over the medial elbow (2%), one with two or more wounds at different locations (2%), and two patients had unknown wound locations secondary to insufficient documentation in the medical record (3%).

Table 1
Table 1:
Gustilo and Anderson distribution of open fractures of the proximal ulna

The mechanism of injury included 35 high-energy injuries (58%), including 25 motor vehicle accidents and 10 falls from greater than standing height, and 24 low-energy falls (40%; from standing height or below). One patient had an unknown mechanism secondary to insufficient documentation in the medical record. Nineteen patients (32%) sustained trauma to multiple parts of the body. Twenty-one patients (35%) sustained one or more upper extremity injuries in addition to the proximal ulna fracture, including humerus fracture (12), radius fracture (six), hand injury (three), neurovascular damage (three), closed olecranon fracture on the contralateral side (one), and ulnar collateral ligament tear (one).

Fracture Management

On presentation, all patients received intravenous antibiotics per institutional protocol. They received a first-generation intravenous cephalosporin or equivalent medication if they had a penicillin allergy. Intravenous antibiotics were continued until the patient was taken to the operating room and for at least 24 hours after the initial débridement. The treating surgeon selected the treatment choice according to his or her preference and all devices were FDA-approved for this use; 21 attending surgeons were involved in the cases in this study.

At the time of initial débridement, 52 patients (87%) underwent immediate open reduction and internal fixation with a plate (33 patients), tension band (16 patients), screw fixation (two patients), or suture anchor fixation (one patient). Six patients (10%) underwent external fixation with conversion to plating or screw fixation at a later date. Two patients were treated nonoperatively (3%).

Of the 58 patients treated operatively, time to débridement was variable: 12 patients were taken to the operating room within 6 hours of presentation (21%), 26 patients were taken between 6 and 24 hours of presentation (45%), and 20 patients were taken greater than 24 hours from the time of presentation (35%; range, 24-96 hours). The reasons for delay included need for medical optimization and limited availability of operative space or staff.

Matching and Statistical Analysis

The 60 open fractures that met inclusion criteria were matched by age and sex to a control group of 91 closed fractures (minimum of one match per subject, two if suitable matches were available) of the proximal ulna from the same time period in a case-control study design. The mean age of the open and closed groups was both 49 years (p = 0.956) and the proportion of men was not different (40 of 60 [67%] versus 62 of 91 [68%] men for the open and closed groups, respectively; p = 0.888). Each fracture was radiographically reviewed and classified by anatomic type as simple or comminuted olecranon fracture, anterior or posterior Monteggia fracture, or anterior or transolecranon fracture-dislocation by four authors in consensus (two fellowship-trained attending orthopaedic surgeons [AJ, DR] and two orthopaedic residents [SRS, AAW]); simple olecranon fractures were regarded as “less complex” than the other types of fractures. The bony injury patterns were compared between the open and closed fracture groups by use of Fisher's exact test with statistical significance set at p < 0.05.

Each fracture was followed until there was radiographic evidence of healing or for a minimum of 6 months, whichever came first. Thirty-nine (65%) of the 60 open fractures had followup at a minimum of 3 months as prespecified with a mean of 22 months (range, 3-86 months) and were matched by age and sex to 39 closed fractures with adequate followup (mean, 15 months; range, 3-51 months); one-to-one matching was performed to use matched pair statistical tests to account for the smaller sample size resulting from loss to followup. The mean age of the open and closed groups was not different (47 years versus 49 years for open and closed groups, respectively; p = 0.615) and the proportion of women was not different (24 of 39 [62%] versus 25 of 39 [64%] women for open and closed groups, respectively; p = 0.853).

Patients were not recalled specifically for this study. At final followup, clinical and radiographic assessments were performed, specifically for ROM, flexion contracture, fracture union status, wound infection, and the need for a secondary procedure for any reason; these parameters were identified from chart and radiographic review by someone other than the operating surgeon. Differences in these outcomes were compared using McNemar's test and paired t-tests, as appropriate, with statistical significance set at p < 0.05.

Results

The open fractures of the proximal ulna did not have overall more complex bony injury patterns compared with the closed fracture group. However, there were more anterior olecranon fracture-dislocations among the open fracture group (15% versus 2%; p = 0.004) and more posterior olecranon fracture-dislocations in the closed fracture group (34% versus 12%; p = 0.002). There were no other differences in the bony injury distribution (Table 2).

Table 2
Table 2:
Bony injury patterns of open versus closed fractures of the proximal ulna

Final ROM (124° versus 129° for open and closed fractures, respectively; p = 0.624) and flexion contracture (14° versus 11° for open and closed fractures, respectively; p = 0.47) were not different between open and closed fractures (Table 3). All fractures healed and there were no malunions.

Table 3
Table 3:
Outcomes and complications of open versus closed fractures of the proximal ulna

There was no difference in wound infection rate between open and closed fractures, but more open fractures required a secondary procedure for any reason (39% versus 23%, p = 0.0135; Table 3); there were 15 secondary procedures in the open fracture group (six irrigation and débridements for wound infections, six plate and screw removals for pain, one plate and screw revision for malunion, and two ulnar reconstructions with allograft [one for arthritis, one for an irreparable ulna; allograft chosen because of surgeon preference]) compared with nine in the closed fracture group (five irrigation and débridements for wound infection, three plate and screw removals for pain, and one plate and screw revision for nonunion).

Discussion

Few data regarding the injury characteristics and outcomes of open elbow fractures exist, particularly for open fractures of the proximal ulna. Two studies indirectly suggest that open fractures of the proximal ulna present with mild soft tissue injuries [5, 8] in contrast to open distal humerus fractures, which often present with complex injury patterns and significant soft tissue injury [6, 11]. Thus, the purposes of our study were to determine the injury characteristics of open proximal ulna fractures and to compare the bony injury patterns, ROM, and union as well as complications with those of closed fractures.

We note several limitations to this study. First, this is a retrospective review with the inherent limitations to such a study design. However, the low incidence of open proximal ulna fractures makes prospectively studying these injuries difficult; such an injury lends itself best to retrospective study. Second, our review reflects the experience of three academic Level I trauma centers, and so our results may not be generalizable to the general population. Similarly, the fact that all three centers in this study are in the same city raises concerns about generalizability, particularly when considering that hand and forearm fracture incidence rates [4] and treatment decisions [1, 2] differ by region of the United States. Additionally, the large number of surgeons involved in the cases in this study introduces potential confounding surgeon-related factors; however, such a feature may mitigate single-surgeon bias. Finally, we had a relatively high loss-to-followup rate for the outcome analysis and, as such, had to perform two separate statistical analyses (matched pair and nonmatched pair) to maximize statistical power. Loss to followup generally would be expected to inflate the apparent benefits of treatment terms of endpoints like union, ROM, and reoperation frequency; one should surmise that missing patients are not doing as well as those with complete followup.

In terms of bony injury characteristics, open fractures of the proximal ulna surprisingly did not have more complex injury patterns than closed fractures with the most common fracture type in both groups being simple olecranon fractures. These findings are consistent with the limited literature on these injuries; to our knowledge, only two studies have previously evaluated the injury characteristics of open fractures of the proximal ulna, albeit in an indirect manner [5, 8]. Court-Brown et al. [5] previously evaluated all open fractures in an adult population over a 15-year period in the United Kingdom and found that 86.3% of open proximal ulna fractures presented as Gustilo and Anderson Type I or II injuries, which is consistent with our findings, as one would expect mild degrees of soft tissue injury to be associated with relatively simple bony injury patterns. Similarly, in an evaluation of proximal ulna fractures at one orthopaedic trauma unit over 1 year, Duckworth et al. [8] reported that of five open fractures of the proximal ulna, all were Gustilo and Anderson Type I and II injuries, further corroborating our findings. Together these previous findings and the observations in our study suggest that the wounds in open fractures of the proximal ulna are likely a tension failure of the skin because of the limited soft tissue envelope around the proximal ulna. The bony injuries, as our study indicates, are not more high-energy or complex than closed fractures and do not have significantly greater soft tissue injuries. Thus, the open injuries are relatively mild (Type I and II) and do not have more complex patterns than closed fractures of the proximal ulna. This mechanism is in direct contrast to open distal humerus fractures, in which an open wound is created by higher energy mechanisms resulting in more complex bony injury patterns with higher levels of soft tissue injury. Because the soft tissue envelope about the humerus is more robust, a high-energy soft tissue injury is needed to create an open fracture. Accordingly, open fractures of the distal humerus present with more severe soft tissue injuries [3, 9, 11-13] than those observed for open fractures of the proximal ulna.

Based on the findings of mild soft tissue injury described for open fractures of the proximal ulna, it is not surprising that we did not find a difference in wound infection rate. It should be noted, however, that the majority of fractures were débrided 6 hours or more after presentation, which is somewhat surprising given our lack of increased wound infections in the open fractures; again, this finding may be explained by the mild soft tissue injury observed for the open fractures and lends further credence to the concept of open fractures of the proximal ulna being the result of skin tension failure secondary to the limited surrounding soft tissue envelope. Interestingly, we did find an increased secondary procedure rate among open and closed fractures of the proximal ulna, although a large portion of these was the result of hardware-related issues. Nevertheless, all fractures healed with zero malunions occurring in either group with no differences in final ROM and flexion contractures. Although no study has evaluated the outcomes of open fractures of the proximal ulna, literature on open fractures of the distal humerus demonstrate that these injuries have greater stiffness, higher infection rates, and overall worse outcomes compared with closed fractures of the distal humerus [3, 7, 10]. Our findings stand in contrast to these findings and suggest that open fractures of the proximal ulna have no difference in outcomes compared with closed fractures, perhaps secondary to their relatively low-energy mechanisms of injury and mild soft tissue injury.

In summary, our study describes the injury characteristics and clinical outcomes (specifically, ROM, fracture union, and reoperations) of open fractures of the proximal ulna. Our results suggest that open fractures of the proximal ulna are primarily intraarticular injuries that present with mild soft tissue injuries and fracture patterns, clinical outcomes, and wound infection rates that are not different from those of closed fractures of the proximal ulna. Open fractures, however, appear to require secondary surgeries more often and perhaps with more demanding, complex procedures such as ulnar reconstruction with bone grafting. Our findings suggest that open fractures of the proximal ulna are the result of tension failure of the skin secondary to the limited soft tissue envelope around the proximal ulna. Open fractures of the proximal ulna should be regarded as relatively mild injuries that are not different in severity and prognosis compared with closed fractures. Accordingly, patients should be counseled that open fractures of the proximal ulna appear to have no difference in outcomes from their closed counterparts. Future study should be aimed at confirming our findings in other geographic and clinical settings, because our study population represented Level I trauma centers in the same city.

Acknowledgments

We thank David Ring MD, PhD for his guidance in study design and data analysis.

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