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Objective:To investigate the changes and clinical significance of white blood cell (WBC) count and polymorphonuclear cells (PMN) proportion of synovial fluid after primary total knee arthroplasty (TKA).Methods:A total of 59 patients (92 knees) who underwent TKA from April 2021 to July 2021 were included, including 13 males (20 knees) and 46 females (72 knees). The patients were with average age 65.17±7.49 years old (range 48-79) and with body mass index (BMI) 27.64±3.74 kg/m 2 (range 17-36 kg/m 2). There were 26 cases involved lateral knee and 33 cases bilateral knees. The left knee was involved in 46 knees, while other 46 were involved in right side. There were 54 patients diagnosed as osteoarthritis (84 knees) and 5 as rheumatoid arthritis (8 knees). None of the patients received antibiotics after hospitalization. Antibiotics were used prophylactically 30 min before surgery and after surgery. The synovial fluid WBC count and PMN proportion were detected during operation (It reflects the normal preoperative level) and on the 2nd, 5th and 35th day after operation. The changes of these indexes were analyzed. The unmixed synovial fluid was collected after the incision of the joint capsule during the operation. The outer upper edge of the patella was taken as the puncture point to extract the synovial fluid on the 2nd, 5th and 35th days after the operation. The final follow-up end point was a diagnosis of acute periprothetic joint infection (PJI) or 90 days of follow-up for patients without PJI. Results:After operation, the synovial fluid WBC count and PMN proportion showed a trend of increasing and then decreasing. The synovial fluid WBC count were 0.222(0.100, 0.567)×10 9/L, 20.011(14.573, 29.129)×10 9/L, 6.080(3.676, 8.797)×10 9/L, 0.533(0.394, 0.749)×10 9/L before surgery and at 2nd, 5th and 35th day after surgery respectively. The difference before and after operation was statistically significant (χ 2=247.343, P<0.001). The synovial fluid PMN proportion were 19.9%(15.0%, 30.0%), 96.0%(95.0%, 97.0%), 91.0%(89.0%, 93.0%) and 20.5%(15.6%, 26.9%) respectively and with significant difference (χ 2=242.521, P<0.001). Pairwise comparison of synovial fluid WBC count and PMN proportion before and on day 35 indicated no statistical significance ( P>0.05). However, the differences compared with that at other time points were statistically significant ( P<0.05). Conclusion:The synovial fluid WBC count and PMN proportion increased rapidly in the short term after TKA and then decreased to the preoperative level at varied rates. Referring to the Musculoskeletal Infection Society (MSIS) recommended threshold for diagnosing infection during the acute stress period (within 5 d postoperatively) can result in false positives. Recovery to preoperative levels at 35th days postoperatively can be used as a basis for ruling out early infection. Thus, early joint fluid PMN proportion may have more diagnostic value than WBC counts.
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Objective:To study whether early leukocytosis after total joint arthroplasty (TJA) requires further workup to exclude infection by observing changes in peripheral blood white blood cell (WBC) count after TJA.Methods:This study included the 294 patients (infection-free group) who had undergone primary hip or knee TJA from June 2019 to June 2020 but reported no periprosthetic joint infection (PJI) within one month after surgery and the 31 patients (infection group) who had undergone the same TJA but reported infection within one month after surgery from May 2012 to June 2020 at Department of Joint Surgery, The First Affiliated Hospital to Xinjiang Medical University. Peripheral blood WBC counts were measured and recorded before surgery and 1 to 5 days after surgery. Differences were compared between time points and multiple linear regression analysis was used to screen the factors associated with early postoperative leukocytosis. The receiver operating characteristic (ROC) curve was used to evaluate the predictive value of WBC for early PJI.Results:The peripheral WBC level in the infection-free group showed a trend of increasing at first and then decreasing. It reached the peak on day 2 after surgery, increasing by 8.08×10 9/L±2.33×10 9/L compared to pre-surgery, and then began to decrease to a level slightly higher than the preoperative value on day 5 after surgery. The changes in WBC count in the first 2 days after surgery ranged from 6.24×10 9/L to 26.32×10 9/L. The incidence of leukocytosis in the first 5 days after surgery was 95.6% (281/294). The factors associated with postoperative leukocytosis included preoperative WBC count and bilateral surgery. For every increase of 1.00×10 9/L in preoperative WBC count, the postoperative WBC value increased by an average of 0.98×10 9/L [ β=0.984, 95% confidence interval (95% CI): 0.821-1.148, P<0.001]. The postoperative WBC count in the patients undergoing bilateral surgery increased by an average of 1.03×10 9/L compared with that in the patients undergoing unilateral surgery ( β=1.026, 95% CI: 0.565-1.486, P<0.001). The area under the curve (AUC) for prediction of early PJI by absolute WBC count difference (the absolute difference between the maximum postoperative WBC value and the baseline) was 0.655 (95% CI: 0.546-0.764, P<0.05), providing a threshold of 7.96×10 9/L, a sensitivity of 57.5% and a specificity of 74.2%. Conclusions:Leukocytosis is a common phenomenon after TJA, indicating a normal physiological response to surgery. The preoperative WBC count is a predictor for postoperative leukocytosis. In the absence of abnormal clinical symptoms or signs, there is no need for further workup to check infection if the postoperative WBC does not deviate from its changing range and trend.
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Objective To present clinical effects of debridement, antibiotics, irrigation and retention of implant (DAIR) with integrated antibiotics application in treating periprosthetic joint infection (PJI) occurred within 3 months after primary surgery. Methods We retrospectively analyzed patients who received DAIR between January 2011 and October 2015. A total of 49 pa?tients with a mean age of 62.38±14.56 years (range, 26-82 years) were included in this study, including 29 males and 20 females. There are 27 knees and 22 hips. Twenty?three patients has sinus tract. Failure was defined as subsequent surgical intervention for infection after the index procedure; persistent fistula, drainage, or excessive joint pain at the last follow?up; death related to the PJI; chronic suppression with antibiotics. Results There were 18 (36.7%) culture negative cases and 31 (63.3%) culture positive cases, including 28.6% (14/49) methicillin?sensitive staphylococcus aureus, 4% (2/49) methicillin?resistant staphylococcus aure?us, 2% (1/49) methicillin?resistant staphylococcus epidermidis, 2%(1/49) mixed infection with fungus and so on. Within the 68.34± 14.02 months (range, 39-94 months) follow?up duration, the Knee Society Score (KSS) score was improved from 38.37 ± 12.39 points (range, 18-62 points) pre?operatively to 82.26±10.50 points (range, 49-96 points) post?operatively (t=-17.09, P<0.001). KSS function score was improved from 42.19±10.14 points (range, 26-67 points) pre?operatively to 75.22±11.60 points (range, 41-90 points) post?operatively (t=-12.53, P<0.001). Harris hip score was improved from 47.41±8.39 points (range, 32-58 points) pre?operatively to 86.41±6.07 points (range, 71-96 points) post?operatively (t=-23.38, P<0.001). There were 6 patients receiving sub?sequent surgical intervention as failure. The mean duration from the index surgery to failure was 5.75±3.00 months (range, 1.5-10 months). Conclusion The present protocol of DAIR for dealing with early?stage PJI, which is less than 3 months after primary TKA or THA, is fairly effective.
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Objective To investigate the short-term outcomes after revision hip arthroplasty for severe acetabular bone deficiency by cup-cage.Methods We retrospectively analyzed 16 patients (16 hips) with Paprosky type Ⅲ B acetabular bone deficiency,who received cup-cage from October 2013 to May 2016.There were 6 males and 10 females,with an average age of 62.6 years (range 40-84 years).All but one patient were with pelvic discontinuity.The reason for revision was aseptic loosening for 14 patients and periprosthetic joint infection for 2.Eleven patients underwent surgery via Trabecular Metal Acetabular Revision System (cup+cage),2 via Trabecular Metal cup and AR cage,and 3 via R3 cup and AR cage.During the follow-up,Harris hip score was recorded to evaluate the clinical efficacy,and X-rays were performed to identify the signs of loosening and changes in rotation center position.Results The mean follow-up was 18.7 months (range 6-36 months).The height of rotation center was decreased from 42.00±12.18 mm preoperatively to 22.75±8.44 mm postoperatively,whereas the horizontal distance of the rotation center was 26.81 ±7.61 mm preoperatively and 32.50±6.51 mm postoperatively (t=8.249,P＜0.001;t=-4.786,P＜0.001).The height of the rotation center was slightly higher than that of the contralateral side postoperatively (t=-3.478,P=0.003),whereas the difference in the horizontal distance of the rotation center between the two groups was not statistically significant (t=1.235,P=0.236).The Harris hip score was improved from 45.63± 11.68 preoperatively to 75.78±9.12 postoperatively (t=-12.157,P＜0.001).During the follow-up,one dislocation occurred at 5 days postoperatively and closed reduction was conducted under anesthesia.There was no blood vessel injury,nerve injury,wound complication and periprosthetic joint infection.No recurrence of infection occurred in 2 patients who received revision hip arthroplasty for periprosthetic joint infection.Conclusion Revision hip arthroplasty for Paprosky Ⅲ B acetabular bone deficiency by cup-cage can achieve good primary stability and reconstruct the rotation center,especially for patient with pelvic discontinuity.