Risk factors for ecchymosis around the wound after total knee arthroplasty

Objective To analyze clinical risk factors for ecchymosis around the wound after total knee arthroplasty (TKA). Methods From January, 2007 to May, 2010, 102 patients, 14 men and 88 women, received TKA in our hospital. Their average age was (65.9 ±7. 1) years (range, 51 to 79 years).Their average body mass index was (28. 6 ± 4. 8) kg/m2. Fifteen clinical factors were analyzed retrospectively to determine their associations with postoperative ecchymosis around the wound. Seven continuous variables were analyzed by t and χ2 tests while 8 categorical variables were analyzed by one-way ANOVO. All the 15 possible risk factors for postoperative ecchymosis around the wound were analyzed with multivariate logistic regression. Results The incidence of ecchymosis around the wound in this series was 13.7%(14/102). Single factor analysis indicated difference in blood transfusion was significant (t = 2. 707, P =0. 008);χ2 test indicated difference in blood transfusion volume (＞ 400 mL vs. ＜ 400 mL) was significant (χ2 =7. 495, P =0. 024) . Single factor χ2 test showed drainage-clamping vs. non-drainage-clamping was significant (χ2 = 5. 386, P = 0. 020). Logistic regression analysis indicated that blood transfusion and wound drainage-clamping were the risk factors for the occurrence of ecchymosis around the wound after the TKA.Concluslons Blood transfusion and wound drainage-clamping may be the risk factors for occurrence of ecchymosis around the wound after TKA. Consequently, blood transfusion volume should be controlled and clamping should be avoided as much as possible to ensure smooth drainage if no major vascular injury exists. Key words: Arthroplasty, replacement, knee;  Ecchymosis;  Risk factors