Ottawa Ankle Rules accurately assess injuries and reduce reliance on radiographs
Meta-analysis. To synthesize results from a large number of studies of the Ottawa Ankle Rules, a meta-analysis involving 27 studies including over 15,000 patients found that evidence supported the rules as an instrument for clinically excluding fractures of the ankle and midfoot. This analysis noted the sensitivity of 1.0 found in virtually every study and estimated that the Ottawa Ankle Rules would decrease the need for films by 30% to 40%.10
The Ottawa Ankle Rules and children
The original Ottawa Ankle Rules were applied strictly to adults, but they also have been studied considerably in the care of children. Pediatric studies have documented sensitivities ranging from 97% to 100% and specificities from 24% to 47%. All studies have shown significant decreases in unnecessary films and significant cost savings. The conclusion of all authors was that the Ottawa Ankle Rules are a cost-effective, highly sensitive test for evaluating acute ankle injuries in children. 11-14
However, researchers at the University of Colorado prospectively evaluated the use of Ottawa Ankle Rules in children aged <18 years. The previous studies had used the same criteria as used for adults, but because of the uncertainty of the long-term effects of Salter I (epiphyseal injury) or small (<3 mm) avulsion fractures in the pediatric population, those injuries were included in the fracture category. This brought the sensitivity down to 83%, with a negative predictive value of 93%. The authors suggested that the Ottawa Rules not be employed in the pediatric population.15 Clearly, more work needs to be done in order to clear them for use in children.
Using the rules reduces costs
Researchers analyzed the cost effectiveness of the rules in the US.16 Variables used to estimate savings included waiting time and lost productivity as well as the obvious medical and radiographic costs. Previous studies have indicated at least a 28% decrease in unneeded ankle films.4 By using this admittedly conservative reduction, it was estimated that the savings would range from $18 to $90 million annually (depending on payer mix involved). Even the smaller amount represents a significant cost savings.
Rule modifications could increase specificity
Because of the low specificity of the Ottawa Rules (a large number of false-positive results are still obtained), sports medicine physicians at the University of Buffalo determined that a modified set of ankle rules could increase specificity significantly. These rules, called the “Buffalo Rules,” kept most of the original rules but changed the original area of fibular tenderness from the posterior and inferior malleolar edges to the midline crest. Using this modification maintained the high sensitivity of the original rules and decreased the need for radiographs from 34% to over 50% (SOR: B).7
Patient satisfaction not dependent on films
While most radiographs done for acute ankle injuries are not helpful, many physicians believe patients expect them and will be dissatisfied or upset if films are not taken. A recent Canadian study evaluated the claim that patient preferences influenced physician test ordering and compliance with clinical guidelines. Specifically it looked at emergency department implementation of the Ottawa Ankle Rules and patient satisfaction.17
This study of almost 1000 patients, split between a population who received films and those who did not for an acute ankle or midfoot injury, indicated that patients who did not get radiographs were just as satisfied with their care as those that did. In the study, 76% of physicians supported the use of clinical guidelines, but 78% admitted that patient expectations influenced their decision making. These rules would likely be of great value where radiographic facilities are inconvenient or costly for patients.
Correspondence
Dr. Paul J. Nugent, 4411 Montgomery Rd, Suite 200, Cincinnati, Ohio 45212. E-mail: pjnuge@aol.com.
