XXXX is common after total hip and knee arthroplasty.

@entity1 @entity2445 @entity281 @entity86 @entity491
BACKGROUND: @entity86 is a potentially devastating complication after @entity2445 and TKA. In the early postoperative period, clinicians often find nonspecific indicators of @entity281 . Although @entity491 may be a sign of a developing @entity281 in the early postoperative period, it may also be part of a normal surgical response. QUESTIONS AND PURPOSES: We determined (1) the natural history of white blood cell values after primary @entity2445 and TKA, (2) factors associated with early @entity86 , and (3) the predictive value of white blood cell count for early postoperative @entity281 . @entity1 AND METHODS: Using our institutional database, we identified all @entity2445 and TKA cases between January 2000 and December 2008. We determined the incidence of @entity491 and characterized the natural history of postoperative white blood cell counts. We then investigated potential indicators of @entity86 , including development of early @entity281 . RESULTS: The average postoperative white blood cell count increased to approximately 3   10(6) cells/ L over the first 2 postoperative days and then declined to a level slightly higher than the preoperative level by Postoperative Day 4. The incidence of @entity86 for all @entity1 was 38%. Factors associated with @entity86 included TKA, bilateral procedures, older age, and higher modified Charlson Comorbidity Index. The sensitivity and specificity of white blood cell count for diagnosing early @entity281 were 79% and 46%, respectively. CONCLUSIONS: @entity86 is common after @entity2445 and TKA and represents a normal physiologic response to surgery. In the absence of abnormal clinical signs and symptoms, @entity86 may not warrant further workup for @entity281 . LEVEL OF EVIDENCE: Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.
