The epidemiology and injury patterns of acetabular fractures: are the USA and China comparable?
BACKGROUND
Acetabular fractures are rare injuries in heterogeneous patient groups, making it difficult to develop adequately powered prospective single-center clinical trials in the USA or Europe. Chinese trauma centers treat a high volume of these injuries, and if the patient population and injury patterns are comparable to those in the USA, this might support development of multicenter studies in Level I trauma centers in the two countries.


OBJECTIVE
We determined whether the following parameters were similar between operative acetabular fractures treated at Chinese and US trauma centers: (1) epidemiology of injured patients, (2) mechanism of injuries and fracture types, and (3) hospital stay parameters, including symptomatic postoperative deep vein thrombosis (DVT) rate.


METHODS
We extracted data from trauma databases for patients admitted with acetabular fractures managed surgically from 2005 to 2012 for one Chinese center and from 2008 to 2012 for one US center. Sex, age, mechanism of injury, fracture classification, Injury Severity Score (ISS), time from injury to surgery, length of hospital stay, and symptomatic DVT rate were analyzed. We included 661 Chinese patients (539 men, 122 women) and 212 US patients (163 men, 49 women).


RESULTS
Mean age at time of injury was different between China and the USA, at 40 years with a unimodal distribution and 44 years with a bimodal distribution (p<0.001), respectively. Incidence of surgically treated acetabular fractures has been increasing in China but decreasing in the USA. Mean ISSs were comparable. Although the distribution of mechanisms of injury was different (p=0.004), high-energy injuries (motor vehicle accidents, falls>10 feet) still accounted for most fractures in both centers. Fracture classifications (per Letournel) were comparable, with posterior wall fractures most common. Mean time from injury to surgery and mean hospital stay were longer in China than in the USA (9 versus 3 days [p<0.001] and 26 versus 11 days [p<0.001], respectively). Symptomatic DVT rates were comparable.


CONCLUSIONS
Although we identified differences between the two centers, we also noted important similarities. Multicenter clinical studies involving these locations should be performed with caution and focus on similar end points, taking into account the populations' baseline differences. Because of the potential for such differences, this kind of validation study should be performed before embarking on resource-intensive multicenter trials.


METHODS
Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.
Department of Orthopaedic Surgery, Denver Health Medical Center, University of Colorado, School of Medicine, 777 Bannock Street, Denver, CO, 80204, USA, cyril.mauffrey@dhha.org.
Cyril
C
Mauffrey
Jiandong
J
Hao
Derly O
DO
Cuellar
Benoit
B
Herbert
Xiao
X
Chen
Bo
B
Liu
Yingze
Y
Zhang
Wade
W
Smith
D000077:Acetabulum / Q000293:injuries* / Q000601:surgery; D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002681:China / Q000453:epidemiology; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data; D015897:Comorbidity; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology* / Q000601:surgery*; D006801:Humans; D015601:Injury Severity Score; D007902:Length of Stay / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic / Q000706:statistics & numerical data; D011183:Postoperative Complications / Q000453:epidemiology*; D016730:Program Development; D012189:Retrospective Studies; D017678:Sex Distribution; D014193:Trauma Centers / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology; D020246:Venous Thrombosis / Q000453:epidemiology*; D055815:Young Adult