Antero-posterior axis of the tibia is a better landmark for tibial component rotation in Oxford medial unicompartmental knee arthroplasty.

BACKGROUND: This retrospective study compares tibial component rotations and radiological and functional outcomes in patients who underwent Oxford medial unicompartmental knee arthroplasty (UKA), using the antero-posterior (AP) tibia axis or anterior superior iliac spine (ASIS) as the landmarks for the direction of the vertical cut. METHODS: A total of 86 patients, who underwent Oxford medial UKA were divided into 2 groups, each consisting of 43 patients, according to the use of AP axis (group I) or ASIS (group II) as landmarks for the rotation of vertical tibial cut and compared for the radiological and functional outcomes. Tibial component rotations (α-angle), involvement of the posterior cruciate ligament (PCL) fossa, and instant bearing position (IBP) were measured on computed tomography (CT) images. Functional outcomes were evaluated using Oxford knee score (OKS) and Knee Society score (KSS). RESULT: The median α­angle was significantly smaller in group I than group II (2.5°, range -4-5.5° vs. -6°, range -13-0.5°, p < 0.001). The rates of PCL fossa involvements were 14 (32.6%) and 17 (39.5%, p = 0.7). The median flexion angle of the femoral component (7° vs. 10.5°) and posterior tibial slope (6° vs. 8°) were significantly lower in group I than group II (p = 0.001). All other radiological parameters, preoperative and final OKS and KSS were statistically similar in both groups. CONCLUSION: Taking the AP tibial axis as a landmark for vertical tibial cut rotation provides more neutral tibial component rotation in Oxford medial UKA compared to ASIS; however, this difference may not influence the clinical outcomes.

Sonication of explants enhances the diagnostic accuracy of synovial fluid and tissue cultures and can help determine the appropriate antibiotic therapy for prosthetic joint infections.

PURPOSES: This study aimed to evaluate the sensitivity and specificity of the sonication cultures according to the International Consensus Meeting 2018 criteria and to evaluate the effect of sonication on the antibiotic treatment of patients. METHODS: Sixty-four patients who were scheduled for revision hip or knee arthroplasties were included in the study. Aspiration fluid, tissue, and sonication cultures were performed from all patients and compared in terms of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy. Other targets of the study were to investigate the rate of change in the antibiotic treatment. RESULTS: The sensitivity, specificity, PPV, NPV, and overall accuracy of the fluid culture obtained by the sonication method were 71.4%, 96.6%, 96.2%, 73.7%, and 82.8%, respectively. The sensitivity, specificity, PPV, NPV, and overall accuracy of the fluid culture obtained after tissue sampling were 68.6%, 100%, 100.0%, 72.5%, and 82.8%, respectively. There was no statistically significant difference between the sonication method and tissue culture in terms of sensitivity and specificity (p = 1.0). The sensitivity, specificity, PPV, NPV, and overall accuracy of the fluid culture obtained by the aspiration method were 28.6%, 93.1%, 83.3%, 51.9%, and 57.8%, respectively. Treatment change was applied in 10 (15.6%) patients. CONCLUSION: Our prospectively collected data revealed that sonication of the explants alone did not increase the sensitivity, and we found that sonicate culture sometimes changed the antibiotic therapy strategy in patients with periprosthetic joint infection because different microorganisms were detected. TRIAL REGISTRATION: This study was prospectively registered in a public trials registry ( https://clinicaltrials.gov/ , NCT04304885).

Two-surgeon simultaneous bilateral total knee arthroplasty does not provide poor prosthetic alignment : A prospective randomized controlled study.

PURPOSE: Two-surgeon, simultaneous bilateral total knee arthroplasty (TKA) is considered as an unpredictable, complex procedure in terms of its radiographic and functional outcomes because of different surgeons and teams, and too many instruments and hands in a narrow space. We compared radiological and functional results of simultaneous bilateral TKA and single-surgeon sequential bilateral TKA. METHODS: The 136 participants with a minimum of 24 months follow-up were prospectively randomized into 2 groups: two-surgeon bilateral TKA and single-surgeon bilateral TKA. We prespecified primary outcome of the study as between-group differences in terms of component alignment in the coronal and sagittal planes. Short-term functional outcomes were evaluated prospectively using the Oxford Knee Score (OKS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). RESULTS: Each group consisted of 136 knees of 68 patients. The mean tibial medial angles (TMA) were 89°â€¯± 3 ° and 88°â€¯± 5° in two-surgeons and single surgeon groups, respectively (p = 0.24). Radiological outcomes showed that the mean femoral lateral angles (FLA) were 87.9 ± 3.5° and 85.84 ± 3.7° (p = 0.12), posterior tibial slope angles (PTSA) were 8.2 ± 16.9° and 7.6 ± 17.8° (p = 0.84), and femoral flexion angles (FFA)were 86.8 ± 3.8° and 86.3 ± 3.5° (p = 0.41), anterior femoral offset ratios (AFOR) (%) were 29.5 ± 11.1 and 27.7 ± 7.9 (p = 0.31), and posterior femoral offset ratio (PFOR) (%) were 108.41 ± 31.3 and 108.45 ± 25.7 (p = 0.98), respectively. CONCLUSION: Two-team simultaneous bilateral TKA is as safe as single stage one-surgeon sequential bilateral TKA in terms of short-term component radiological and the functional outcomes.

Could intermittent change of conventional dressing affect risk of periprosthetic joint infection after primary total joint arthroplasty?

PURPOSE: Periprosthetic joint infection (PJI) is one of the most dreaded and challenging complications after total joint arthroplasty (TJA). The aim of this study was to evaluate the effect of keeping the dressing without change on the occurrence of PJI in patients undergoing TJA. METHODS: 4877 Patients with a minimum follow-up of 90 days were included to investigate the effect of dressing on the PJI occurring within 3 months of surgery. Patients were divided into two consecutive groups as the intermittent change of traditional dressing (group 1-before 2019) and keeping dressing for 5 days without change (group 2-after 2019). A backward stepwise logistic regression model was used to estimate independent risk factors for PJI. RESULTS: Group 1 and group 2 consisted of 4172 and 705 patients, and the numbers of diagnosed PJI cases in the groups were 40 (1.0%) and 10 (1.4%), respectively (p = 0.1). The backward stepwise logistic regression model analysis revealed that keeping the dressing unchanged and removing it after the first week postoperatively was not an independent risk factor for the occurrence of PJI. Older age, diabetes mellitus and coronary artery diseases were independent risk factors for PJI (p < 0.05). CONCLUSION: Our study results present, that intermittent change of conventional dressing is unnecessary, because it does not decrease the risk of PJI after TJA. LEVEL OF EVIDENCE: Level III Therapeutic.