In recent years, due to the frequent occurrence of medical accidents, many medical workers have made many patients perform excessive routine laboratory tests out of their own protection. This not only causes a great financial burden to patients, but also an unreasonable control of medical resources. Many studies4,13 have shown that routine postoperative laboratory tests are not needed because they do not serve a certain degree of clinical value. However, it is necessary for those patients with risk factors to undergo postoperative laboratory testing4,14. Many studies suggest that inappropriate laboratory testing should be reduced to better improve the quality of care and reduce healthcare costs. The purpose of this study was to define when routine laboratory testing in patients following knee arthroplasty may or may not be necessary.
Laboratory tests are very helpful in the diagnosis and progression of the disease, but not the more the better. In his research, Gerald et al.15 revealed that the more laboratory tests a patient is subjected to, the more likely it is that an abnormality will eventually be found. To a certain extent, however, if the laboratory test results do not have clinical reference value, then the test is not necessary. Many studies have shown that routine postoperative laboratory tests are not required in most cases unless risk factors are present3,4,13,14,16,17. Li et al.14 showed that nearly 50% of patients undergoing high tibial osteotomy had abnormal postoperative laboratory results, but less than 4% required clinical intervention, suggesting that routine postoperative serology is not required for the majority of patients laboratory test. In our study, up to 95% of postoperative test results were abnormal, but only about 8% required intervention, indicating that in most cases, patients with TKA do not need routine laboratory tests after surgery.
Dai et al18 reported that age and low hemoglobin on admission were important risk factors for perioperative blood transfusion. Armin et al19 retrospectively analyzed 8461 elderly patients over 65 years of age who underwent hip replacement in the United States in 2016 and found that older age and preoperative anemia were independent risk factors for postoperative blood transfusion. Cao et al20 retrospectively analyzed 414 patients with total hip arthroplasty and 1147 patients with total knee arthroplasty and found that increased intraoperative blood loss was a risk factor for postoperative blood transfusion. Consistent with previous studies, in our study, older age, low preoperative hemoglobin, and increased intraoperative blood loss were found to be significant risk factors for postoperative blood transfusions.
In a retrospective study, Wu et al13. analyzed 213 patients undergoing dance hip arthroplasty and showed that the incidence of postoperative albumin was 72.3%, of which 19.7% received clinical intervention. Our study found that the incidence of postoperative abnormal serum albumin was as high as 96.5%, but only 9.9% of patients received clinical intervention, which was lower than reported by Wu et al. In another study, Wu et al12. found that long operative time and low preoperative albumin levels were risk factors for postoperative albumin supplementation, which is consistent with our findings. In addition, we also found that increased intraoperative blood loss is also an important factor for albumin supplementation, as increased operative time increases intraoperative blood loss in patients.
Li et al14. analyzed 482 patients undergoing high tibial osteotomy and found that the proportion of postoperative electrolyte abnormalities was low, including 3.5% of abnormal serum potassium. Preoperative serum potassium concentration below 3.45mmol/L was an independent risk factor for postoperative potassium supplementation. In a retrospective study, Jordan et al10 analyzed data from 213 patients undergoing shoulder arthroplasty and found that postoperative electrolyte abnormalities were strongly associated with lower BMI. Consistent with the above findings, in this study, we found that postoperative patients had a lower probability of electrolyte abnormalities, preoperative serum potassium concentration less than 3.68mmol/l, and BMI less than 21.89 were important risk factors for postoperative potassium supplementation.
There are some shortcomings in this study. First of all, this is a single-center retrospective study, there are some missing data, and the number of included studies is limited, which will lead to biased results to a certain extent. Second, there are certain differences among different surgeons in intervening on abnormal postoperative laboratory tests, which will also bias the final analysis results. Therefore, it is necessary to conduct a multicenter study with a larger sample to verify the effectiveness of these risk factors in predicting the need for clinical intervention in patients with abnormal laboratory tests after TKA.