Ryohei Takada

Is Drain Tip Culture Prognostic of Surgical Site Infection? Results of 1380 Drain Tip Cultures in Total Hip Arthroplasty

The purpose of this study was to evaluate a prognostic value of drain tip culture for surgical site infection (SSI) after total hip arthroplasty. A total of 1380 closed suction drain tips cultured after removal in primary total hip arthroplasty were included in this study. Drains were removed in 12-72 hours after surgery. Drain tip cultures were positive in 11 cases (0.8%). SSI was found in 4 cases (0.3%), where the drain tip cultures were all negative. The sensitivity of drain tip culture for infection after surgery was 0%, and the specificity was 99.7%. We concluded that, drain tip culture cannot be prognostic for SSI after total hip arthroplasty. Routine use of drain tip culture is not supported.

Comparison of wear rate and osteolysis between second-generation annealed and first-generation remelted highly cross-linked polyethylene in total hip arthroplasty. A case control study at a minimum of five years

BACKGROUND There is no previous report that directly compared wear resistance of second-generation annealed highly cross-linked polyethylene with that of first-generation remelted highly cross-linked polyethylene. We therefore performed a retrospective study at a minimum of 5-year follow-up comparing second-generation annealed and first-generation remelted highly cross-linked polyethylene in order to: (1) assess wear rates and (2) compare the incidence of osteolysis between, (3) identify the frequency of complication related to the two types of highly cross-linked polyethylene. HYPOTHESIS There is a difference in the linear wear rate and the incidence of osteolysis between the two types of highly cross-linked polyethylene in total hip arthroplasty. MATERIALS AND METHODS In a single centre study, we reviewed 123 primary cementless total hip arthroplasties between 2010 and 2011 that were performed with 32mm alumina ceramic on second-generation annealed (X3) or first-generation remelted (Longevity) highly cross-linked polyethylene liner. There was no specific reason for the choice of the type of highly cross-linked polyethylene. There were no significant differences between the two groups in respect of gender, diagnosis, body mass index, pre- and post-operative functional and activity score, cup size, and cup orientation except the younger age in the X3 group. The mean wear rate and the incidence of osteolysis were evaluated at the latest follow-up. RESULTS One hundred nine cases followed over 5 years post-operatively (88.6% in all consecutive cases) were evaluated. X3 and Longevity were used in 54 and 55 cases, respectively. The mean follow-up was 5.3 years in both groups. The mean linear wear rate of X3 and Longevity group was 0.045±0.023mm/year and 0.076±0.031mm/year, respectively (P<0.001). No osteolysis was found on plain X-rays in both groups and no specific complication was related to these highly cross-linked components. DISCUSSION Excellent wear resistance of both types of highly cross-linked polyethylene liner was revealed in our study. The difference of wear rate between two materials should be monitored in a longer follow-up. LEVEL OF EVIDENCE Level III retrospective case control study.

Drain Tip Culture is Not Prognostic for Surgical Site Infection in Spinal Surgery Under Prophylactic Use of Antibiotics.

Study Design. A retrospective observational study. Objective. We evaluated the prognostic value of drain tip culture performed for surgical site infection (SSI) after spinal surgery with a large number of subjects, and investigated whether the type of surgery or timing of drain removal correlated with positive drain culture and SSI rates. Summary of Background Data. In many institutions, routine culture of suction drain tips that are placed in the surgical site of spinal surgeries has been performed to detect contamination after removal. However, few reports have evaluated whether drain tip culture is prognostic for SSI after spinal surgery. Methods. A total of 1240 suction drain tips that had been used in spinal surgeries were cultured after removal. Prophylactic antibiotics were administered during and after the surgery for 48 hours. We evaluated the correlation between the results of positive drain tip culture, SSI, and drain removal timing. Results. Positive drain tip cultures were found in 55 cases (4.4%). True SSI was identified in 18 cases (1.5%). The most frequently isolated microorganism in the both cases was Staphylococcus. The sensitivity of drain tip culture for SSI after spinal surgery was calculated as 0% according to the concordance rate between bacteria isolated in drain tip culture and SSI cases. There was no correlation between the duration of suction drainage and the drain tip culture results or the onset of SSI within 72 hours. The results of suction drain tip culture could not reflect those of SSI regardless of the type of surgery (primary or revision), surgical region, surgical procedure, or implant use. Conclusion. Drain tip culture in spinal surgery was not prognostic for SSI or helpful in detecting pathogenic bacteria for SSI. Routine use of drain tip culture when prophylactic antibiotics are used is not supported by the results of this study. Level of Evidence: 4

Limited significance of screening computed tomography after cementless total hip arthroplasty with highly cross-linked polyethylene at 7–10 years of follow-up

Abstract Objectives: The purpose of this retrospective study is to report the incidence of osteolysis and evaluate the significance of screening computed tomography (CT) compared to plain radiography in detecting osteolysis after total hip arthroplasty with metal-on-highly cross-linked polyethylene bearings. Methods: We retrospectively reviewed 264 primary cementless total hip arthroplasties of 211 patients, 24 males, 187 females, who received postoperative screening CT scan in addition to radiography at postoperative 7–10 years (average 8.2 years). First-generation highly cross-linked polyethylene was used in all cases. Results: On the plain radiographs, no acetabular osteolysis (0%) and two cases of femoral osteolysis (0.8%) were found in the follow-up period. No osteolysis was newly found by screening CT scan. Conclusions: Very low incidence of osteolysis after total hip arthroplasty with highly cross-linked polyethylene at postoperative 7–10 years was confirmed, and routine screening CT scan for detecting osteolysis in this setting was not supported from this study.

Do screws and screw holes affect osteolysis in cementless cups using highly crosslinked polyethylene? A 7 to 10-year follow-up case–control study

BACKGROUND The use of screws and the presence of screw holes may cause acetabular osteolysis and implant loosening in cementless total hip arthroplasty (THA) using conventional polyethylene. In contrast, this issue is not fully understood using highly crosslinked polyethylene (HXLPE), particularly in large comparative study. Therefore, we performed a case-control study to assess the influence of screw usage and screw holes on: (1) implant fixation and osteolysis and (2) polyethylene steady-state wear rate, using cases with HXLPE liners followed up for 7-10 years postoperatively. HYPOTHESIS The screw usage and screw holes adversely affect the implant fixation and incidence of wear-related osteolysis in THA with HXLPE. PATIENTS AND METHODS We reviewed 209 primary cementless THAs performed with 26-mm cobalt-chromium heads on HXLPE liners. To compare the effects of the use of screws and the presence of screw holes, the following groups were established: (1) with-screw (n=140); (2) without-screw (n=69); (3) no-hole (n=27) and (4) group in which a cup with screw holes, but no screw was used (n=42). Two adjunct groups (no-hole cups excluded) were established to compare the differences in the two types of HXLPE: (5) remelted group (n=100) and (6) annealed group (n=82). Implant stability and osteolysis were evaluated by plain radiography and computed tomography. The wear rate from 1 year to the final evaluation was measured using plain X-rays and PolyWare Digital software. RESULTS All cups and stems achieved bony fixation. On CT-scan, no acetabular osteolysis was found, but there were 3 cases with a small area of femoral osteolysis. The mean steady-state wear rate of each group was (1) 0.031±0.022, (2) 0.033±0.035, (3) 0.031±0.024, (4) 0.029±0.018, (5) 0.030±0.018 and (6) 0.034±0.023mm/year, respectively. A comparison of the effects of screw usage or screw holes found no significant between-group differences in the implant stability, prevalence of osteolysis [no acetabular osteolysis and 3/209 at femoral side (1.4%)] and steady-state wear rate. DISCUSSION This study suggests that there are no adverse effects on the results of THA with HXLPE from the use of cups with screw holes and the use of screws for cup fixation. LEVEL OF EVIDENCE Level III retrospective case-control study.