Background: The search for potential markers for a timely and accurate diagnosis of periprosthetic joint infection (PJI) is ongoing. Previous studies have focused on inflammatory markers and have rarely examined coagulation-related indicators. The purpose of this study was to evaluate the values of plasma fibrinogen, D-dimer, and other blood markers for the diagnosis of PJI through a multicenter retrospective study. Methods: A total of 565 revision total hip and knee arthroplasty cases were enrolled in this study from January 2016 through December 2017, 126 of which had coagulation-related comorbidities and were analyzed separately. The remaining 439 cases included 76 PJI and 363 non-PJI patients. The definition of PJI was based on the International Consensus Meeting (ICM) on Periprosthetic Infection criteria. The diagnostic values of D-dimer, plasma fibrinogen, the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, and white blood-cell (WBC) count were analyzed using receiver operating characteristic (ROC) curves. Results: ROC curves showed that plasma fibrinogen had the highest area under the curve (AUC), 0.852, followed by 2 classical markers, the CRP level and ESR, which had an AUC of 0.810 and 0.808, respectively. D-dimer had an AUC of 0.657, which was the second lowest value and only slightly higher than that of the WBC count, 0.590. The optimal threshold for plasma D-dimer was 1.25 μg/mL, with a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 0.645, 0.650, 0.278, and 0.897, respectively. The optimal threshold for plasma fibrinogen was 4.01 g/L, which showed good sensitivity, specificity, PPV, and NPV, with values of 0.763, 0.862, 0.537, and 0.946, respectively. Conclusions: Plasma D-dimer may have a very limited diagnostic value for PJI, while plasma fibrinogen, another coagulation-related indicator, exhibits promising performance. Plasma fibrinogen has good sensitivity and specificity for diagnosing PJI, with values similar to those of classical markers, including CRP level and ESR. Level of Evidence: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Background: To our knowledge, no previous studies have compared periprosthetic bone remodeling around monoblock versus modular tapered fluted titanium stems with different stem length and thickness. Methods: A retrospective comparative study was performed on 139 consecutive total hip arthroplasties (THAs) revised with a tapered fluted modular titanium stem and 114 consecutive THAs revised with a tapered fluted monoblock titanium stem. The latest follow-up radiographs were compared with immediate postoperative radiographs to assess bone restoration in residual osteolytic areas, femoral stress-shielding, spot-welds, and radiolucent lines. Diameter and medullary canal filling of the 2 stems were measured. Results: More patients in the monoblock group demonstrated osseous restoration than in the modular group (p = 0.009), and the modular stem exerted more severe stress-shielding on the femur (p < 0.001). Stem tip spot-welds developed in 88.5% of modular stems compared with 47.4% of the monoblock stems (p < 0.001). Spot-welds developed in 38.8% of modular stems at the modular junction. Partial or circumferential radiolucent lines were observed at the proximal segment of 30.9% of modular stems, compared with 14.0% of monoblock stems (p = 0.002). Conclusions: Compared with the longer and thinner monoblock stems, modular stems had less proximal osseous restoration in residual osteolytic areas and more severe femoral stress-shielding, stem tip spot-welds, and radiolucent lines around the stems, which were stiffer and had a shorter distal section. The stem diameter and stiffness (which were influenced by stem length, curvature, and modularity) determined bone remodeling patterns. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Background: The wire fixation and the cable grip fixation have been developed for the extended trochanteric osteotomy (ETO) in the revision of total hip arthroplasty (THA). Many studies reported the postoperative performance of the patients, but with little quantitative biomechanical comparison of the two fixation systems.Methods: An in-vitro testing approach was designed to record the loosening between the femoral bed and the greater trochanter after fixations. Ten cadaveric femurs were chosen in this study. Each femur underwent the THA, revision by ETO and fixations. The tension to the greater trochanter was from 0 to 500N in vertical and lateral direction, respectively. The translation and rotation of the greater trochanter with respect to the bony bed were captured by an optical tracking system.Results: In the vertical tension tests, the overall translation of the greater trochanter was observed 0.4 mm in the cable fixations and 7.0 mm in the wire fixations. In the lateral tension tests, the overall motion of the greater trochanter was 2.0 mm and 1.2° in the cable fixations, while it was 6.2 mm and 5.3° in the wire fixations. The result was significantly different between the two fixation systems.Conclusions: The stability of the proximal femur after ETO using different fixations in the revision THA was investigated. The cable grip fixation was significantly more stable than the wire fixation.

Background: The relevance between the presence of a sinus tract and the failure risk after debridement, antibiotics and implant retention (DAIR) for periprosthetic joint infection (PJI) after hip or knee arthroplasty is still unclear. This study aimed to compare the success rate of DAIR between patients with or without a sinus tract and to explore the possible risk factors for failure after DAIR in patients with a sinus tract. Methods: Consecutive DAIR cases for PJI after hip or knee arthroplasty between January 2009 and June 2019 with a minimum 1-year follow-up in two tertiary joint arthroplasty centers were included. Patients were classified into the sinus tract group and the non-sinus tract group according to the presence of a sinus tract. The success rate after DAIR were compared using Kaplan-Meier survival analysis. Potential risk factors for failure in the sinus group were also explored. Results: One hundred seven patients were included. At a median 4.4 years of follow-up, 19 of 52 (36.5%) cases failed in the sinus tract group, while 15 of 55 (27.3%) cases failed in the non-sinus tract group. The 1-year and 5-year cumulative success rates were 71.2% (95% confidence interval (CI): 59.8-84.6%) and 56.8% (95% CI: 42.6-75.7%) in the sinus tract group, respectively, which were similar to the counterparts in the non-sinus tract group (P = 0.214). Among patients with a sinus tract, DAIR with the exchange of modular components showed a higher success rate (75.8% versus 47.4%, P = 0.038). Conclusions: The presence of a sinus tract does not affect the success rate of DAIR. Modular component exchange in DAIR was proposed for patients with a sinus tract for an improved infection control rate.

Aims: This study aimed to report the surgical techniques and early clinical results of robotic arm-assisted acetabular reconstruction in revision total hip arthroplasty (THA).Methods: Between October 2019 and May 2021, we used the Mako robotic system to perform 62 revision THAs at our hospital. This study included 54 patients who underwent robotic arm-assisted revision THA for acetabular reconstruction. Surgical techniques using the robotic system to reconstruct the acetabulum, including preoperative planning, intraoperative registration, and the accuracy of different registration methods, are reported. The accuracy between the target acetabular component orientation and final orientation was evaluated. The latest follow-up Harris Hip Score (HHS) and radiographs were analyzed.Results: Among the 54 hips included, four types of intraoperative registration methods with different surfaces were developed and registered 65 times. The overall success rate of the registration process was 98.5%. The mean accuracy of successful registration was 0.38 mm (0.2 to 0.5). The median difference between the target and final acetabular component orientations assessed by Mako was 1.0° (-2.0° to 0.0°) for inclination and 0.0° (-1.0° to 1.0°) for anteversion. Four hips were classified as outliers for acetabular component orientation. The reconstructed centres of rotation (CORs) were slightly lower than the anatomical CORs by a mean 4.72 mm (SD 4.71), and shifted laterally by 3.92 mm (SD 4.62) on postoperative radiographs. The median HHS improved significantly from 46.0 (IQR 33.0 to 58.3) preoperatively to 89.0 (IQR 78.3 to 93.0) postoperatively (p < 0.001). The overall satisfaction rate was 86.0% (n = 50). There were no radiological failures at the latest follow-up.Conclusion: Robotic arm-assisted revision THA provides valuable information for the analysis of bone defects to guide reconstructive strategies. Robotic arm-assisted reaming and acetabular component or augment positioning facilitates accurate component position and orientation. The radiological and preliminary clinical results of this cohort were satisfactory.Cite this article: Bone Joint J 2025;107-B(4):404–412.