RT Journal
A1 Bernstein, Joseph
A1 Ahn, Jaimo
T1 Is After-Hours Orthopaedic Surgery Associated with Adverse Outcomes?
JF The Journal of Bone & Joint Surgery
JO The Journal of Bone & Joint Surgery
YR 2010
FD February 1
VO 92
IS 2
SP 524
OP 524
DO 
UL http://dx.doi.org/
AB 
The study perhaps could be considered to be under the category "prognostic studies—investigating the effect of a patient characteristic on the outcome of disease." (In this case, the "patient characteristic" is the time of the operation.) In the JBJS guidelines, a prognostic study can be considered Level I if it was "high-quality." Of course, the height of quality is a subjective judgment, but we question whether this study is of sufficiently high quality to be deemed Level I. For one thing, the two groups were patently dissimilar beyond the variable in question; in addition, the sample size was inadequately powered.