The Impact of Surgical Approach on 90-Day Prosthetic Joint Infection After Total Hip Replacement - A Population-Based, Propensity Score-Matched Cohort Study.

BACKGROUND: Prosthetic joint infection (PJI) is a devastating complication of total hip arthroplasty (THA). This study aimed to determine if the anterior approach (AP) influenced the incidence of early PJI in THA compared to posterior approach (PP). METHODS: Record linkage was performed between state-wide hospitalization data and a national joint replacement registry to identify unilateral THA performed via the AP or PP. Complete data on 12,605 AP and 25,569 PP THAs were obtained. Propensity score matching (PSM) was undertaken to match covariates between the approaches. Outcomes were the 90-day PJI hospital readmission rate(using narrow and broad definitions) and 90-day PJI revision rate (defined as component removal or exchange). RESULTS: The raw PJI readmission rate for AP was lower than PP (0.8% versus 1.1%, respectively). In the PSM analysis, there was no statistically significant difference in PJI readmission rate between approaches using narrow or broad definition of PJI readmission. In terms of revision for infection, both methods showed AP had a significantly lower rate than PP, with an adjusted odds ratio (OR) of 0.47 (95% confidence interval (CI) 0.30, 0.75) for the 1:1 nearest neighbor method and 0.50 (95% CI 0.32, 0.77) for the subclassification method. CONCLUSION: After addressing known confounders, there was no significant difference in the 90-day hospital readmission rate for hip PJI between approaches. There was a significantly reduced 90-day PJI revision rate for AP. The difference in revision may reflect differences in the surgical management of PJI between hip approaches rather than a difference in the underlying rate of infection.

Robotic-assisted surgery and kinematic alignment in total knee arthroplasty (RASKAL study): a protocol of a national registry-nested, multicentre, 2×2 factorial randomised trial assessing clinical, intraoperative, functional, radiographic and survivorship outcomes.

INTRODUCTION: Robot-assisted surgery (RAS) and kinematic alignment (KA) are being increasingly adopted to improve patient outcomes in total knee arthroplasty (TKA). There is uncertainty around the individual or combined effect of these concepts compared with computer-assisted surgery (CAS) and mechanical alignment (MA), respectively. This study aims to assess the effectiveness of RAS, KA or both to improve clinical outcomes, functional measures, radiographic precision and prosthetic survivorship when compared with current gold standards of surgical care. METHODS AND ANALYSIS: A national registry-nested, multicentre, double-blinded, 2×2 factorial, randomised trial will be undertaken with 300 patients undergoing primary unilateral TKA performed by 15 surgeons. The primary outcome will be the between-group differences in postoperative change over 2 years in the mean Knee injury and Osteoarthritis Outcome Score (KOOS-12), comparing first, RAS to CAS as its control, and second, KA to MA as its control. Secondary outcomes will include other knee-specific and general health patient-reported outcome measures (PROMs), intraoperative pressure loads as a measure of soft tissue balance, 6-month postoperative functional outcomes, radiological precision using CT imaging, complications and long-term prosthetic survivorship. The contribution of each patient's unique coronal plane alignment of the knee phenotype to primary and secondary PROMs will be investigated. OMERACT-OARSI criteria and Patient Acceptable Symptom State outcome score thresholds for the KOOS-12 and Oxford Knee Score will be used in secondary analyses. Primary intention-to-treat and secondary per-protocol analyses will be performed. Statistical analysis will include a generalised linear mixed model for repeated measures for continuous KOOS-12 scores. Kaplan-Meier estimates with adjusted HRs of implant survivorship will be calculated. ETHICS AND DISSEMINATION: Ethics approval was obtained from Sydney Local Health District-Royal Prince Alfred Hospital (Approval X20-0494 and 2020/ETH02896 10.24/DEC20). Results will be submitted for publication in a peer-reviewed journal and presented in national, state and international meetings. TRIAL REGISTRATION NUMBER: ACTRN12621000205831.

The diameter of single bundle, hamstring autograft does not significantly influence revision rate or clinical outcomes after anterior cruciate ligament reconstruction.

BACKGROUND: Anterior cruciate ligament (ACL) graft failure is a complication of ACL reconstruction (ALCR). Smaller autograft diameter may be a contributing factor. Our aim was to determine if hamstring autograft diameter influences graft rupture and patient-reported outcome scores. METHODS: This study included 786 consecutive patients undergoing primary, single bundle, autograft hamstring ACLR. The primary outcome was revision ACLR surgery. Secondary outcomes were patient reported International Knee Documentation Committee (IKDC) score, Knee Injury & Osteoarthritis Outcome Score (KOOS) and Tegner Activity score. Multiple logistic regression and Fischer Exact tests were employed for statistical analysis. RESULTS: Increasing autograft diameter did not lead to a reduction in revision ACLR surgery (odds ratio [OR], 1.093; 95% confidence interval [CI], 0.612 to 1.954; P=0.76). Revision ACLR positively correlated with male gender (OR, 3.971; 95% CI 1.109 to 14.214; P=0.03) and negatively correlated with increasing age (OR, 0.919; 95% CI 0.882-0.958, P<0.0001). There was no association between graft rupture rate and dichotomized graft size. At latest follow-up, there was no correlation between graft diameter and IKDC (Pearson's adjusted R2=0.058; P=0.75), Tegner Activity score (Pearson's adjusted R2=0.244; P=0.53), or any component of the KOOS (Pearson's adjusted R2 range: 0.008 to 0.141; P-value range: 0.21 to 0.76). CONCLUSION: Increased hamstring autograft diameter did not significantly reduce revision ACLR surgery or improve clinical outcomes. Other factors such as gender and age do influence the rate of revision ACL surgery. STUDY DESIGN: Level IV, retrospective case series.

Resection accuracy of patient-specific cutting guides in total knee replacement.

BACKGROUND: Patient-specific guides (PSGs) have been thoroughly investigated with regards to reconstitution of mechanical alignment in total knee arthroplasty (TKA). The ability to replicate the preoperative surgical plan is essential for optimal outcomes but intraoperative measurements to confirm accurate progression through the operation are limited. This leads to our clinical question: can PSGs replicate the planned bone resection depth during TKA? METHODS: This is a prospective case series of 118 patients who underwent TKA using magnetic resonance imaging-based patient-specific cutting guides. Intraoperative bone resection thickness was measured and compared with the preoperative planned bone resections as a primary outcome. Secondary outcomes included the need for additional bone resections, the number of cases for which the PSG technique was abandoned, final component sizes and mechanical alignment. RESULTS: PSGs could not accurately recreate preoperative plan. PSGs resulted in over-resection in all bone cuts compared with the preoperative surgical resection plan. Secondary osteotomies were required in 37% of patients. PSGs had to be abandoned in 10.5% of cases, mostly due to suboptimal fit of the femoral block. The tibial component size was altered more frequently than the femoral. CONCLUSION: Intraoperatively, PSGs could not accurately recreate the preoperative plan. PSGs are marketed as user-friendly tools to simplify TKA but our research demonstrates the need for surgeons to monitor surgical progression and compensate for errors occurring during the use of PSGs.

Normal Femorotibial Rotational Alignment and Implications for Total Knee Arthroplasty: an MRI Analysis.

BACKGROUND: Rotational alignment of prosthetic components in total knee arthroplasty (TKA) is important to successful outcomes. Component malrotation is a known cause of revision and understanding normal rotational alignment may help recreate normal joint kinematics. To date, no large MRI study assessing femorotibial rotational alignment in nonarthritic knees has been undertaken. QUESTIONS/PURPOSES: Is Insall's tibial axis a reliable rotational landmark against common femoral rotational axes in the nonarthritic patient population? METHODS: We reviewed 544 knee MRI scans performed for suspected soft tissue pathology and identified Insall's tibial rotational axis as well as the femoral clinical trans-epicondylar axis (TEAc), femoral surgical trans-epicondylar axis (TEAs), posterior condylar articular axis (PCA), and a modified Eckhoff's cylindrical axis. The perpendiculars of these axes were superimposed on Insall's tibial axis, and the angular differences were measured. RESULTS: Insall's axis was internally rotated to the TEAc by 1.4°, externally rotated to Eckhoff's cylindrical axis by 1.8°, externally rotated to the TEAs by 2.7°, and externally rotated to the PCA by 3.5°. The mean deviation from 0° (optimal alignment for each femoral axis) was significantly greater for the PCA relative to all other femoral axis. CONCLUSION: Insall's axis is a reliable landmark for rotational positioning of the tibial component and may optimize femorotibial kinematics in fixed-bearing TKA.

Erratum to: Normal Femorotibial Rotational Alignment and Implications for Total Knee Arthroplasty: an MRI Analysis.

[This corrects the article DOI: 10.1007/s11420-016-9491-y.].

Peri-articular steroid injection in total knee arthroplasty: a prospective, double blinded, randomized controlled trial.

Total knee arthroplasty is a painful operation. Peri-articular local anesthetic injections reduce post-operative pain and assist recovery. It is inconclusive whether intra-operative injections of peri-articular corticosteroids are of benefit. Therefore our clinical question was: in patients with osteoarthritis who are undergoing TKA, does the addition of high or low dose corticosteroid to peri-articular injections of local anesthetic and adrenaline improve post-operative pain and range of motion? We performed a prospective, double-blinded, randomized controlled trial of two different doses of triamcinolone acetate (N = 42 in each group) added to local anesthetic in TKA for osteoarthritis. There were no significant differences in pain scores or ROM between the control and corticosteroid groups. Differences in secondary outcomes were also non-significant. Peri-articular corticosteroids do not appear to be of benefit in TKA.

Comparison of tibial bone coverage of 6 knee prostheses: a magnetic resonance imaging study with controlled rotation.

PURPOSE: To compare the extent of tibial bone covered by the tibial tray in 6 most commonly used total knee arthroplasty designs in order to strike a balance between mediolateral cortical fit and optimal tibial component rotation. METHODS: In 74 men and 27 women aged 17 to 60 (mean, 32) years with suspected soft-tissue injuries, their magnetic resonance images of the knee in full extension were superimposed with scans of the tibial trays of the 6 designs (one asymmetric and 5 symmetric). The tibial coverage by the tray and any posterolateral/posteromedial overhang/underhang were measured. RESULTS: All 6 tray designs achieved tibial bone coverage of over 80%. Only 28% of all trays achieved optimal posterolateral fit, whereas 49% had posterolateral overhang enough to cause popliteal tendon impingement. Although the asymmetric tray provided highest tibial coverage (88%), its rates of relative and absolute posterolateral and posteromedial overhang were also highest (64%). CONCLUSION: The asymmetric tray provided improved tibial coverage at the expense of posterolateral and posteromedial overhang of the tibial tray.