To investigate the Opening wedge High tibial osteotomy (OWHTO) for treating Hidden blood loss (HBL) of knee osteoarthritis during the perioperative period and to analyze its possible risk factors. All of the data were presented by PRESENTING all of the data.

A total of 96 patients with knee osteoarthritis treated by OWHTO from August 2017 to October 2019 were selected, including 34 males and 62 females. The average age was (58±5) between 48 and 66 years old. Perioperative HBL was calculated according to Gross formula. According to HBL following surgery, all patients were divided into low recessive bleeding group (n=75), high recessive bleeding group (n=21), compared two groups of patients with general information, basic diseases, imaging measurement indicators, the multifactor linear regression analysis risk factors that affect the perioperative HBL and the receiver-operating characteristic curve is used to calculate the related data of OWHTO postoperative high predictive value of the recessive loss of blood.

Multivariate Logistic regression analysis showed that operation time (OR=1.057, 95% CI: 1.009, 1.106, P=0.018), BMI (OR=1.298, 95% CI: 1.043, 1.614, P=0.019), hypertension (OR=4.819, 95% CI: 1.445, 16.071, P=0.011) and HKA (OR=1.230, 95%CI: 1.036, 1.459, P=0.018) was an independent risk factor for high latent blood loss after OWHTO surgery, and the difference was statistically significant. The operating characteristic curves of the subjects showed that the operative time, BMI, hypertension and HKA all had good predictive value for high latent blood loss after OWHTO operation, and the area under the curves were 0.684, 0.690, 0.635 and 0.708, respectively.

Operation time, BMI, hypertension and HKA are independent risk factors for high HBL after OWHTO. For patients with obesity, hypertension and severe varus deformity, early intervention measures should be taken to shorten the operation time, which is of great significance for reducing high HBL after OWHTO.