Tibial Slope is Not Associated with Implant Migration Following Cemented Total Knee Arthroplasty With a Single Implant Design.

BACKGROUND: The influence of tibial slope on tibial component migration following total knee arthroplasty (TKA) has not been widely studied, although excessive posterior slope has been implicated in some failures. As implant micromotion measured with radiostereometric analysis can indicate successful fixation, the purpose of this study was to determine the associations between tibial slope, tibial component migration, and inducible displacement. METHODS: Radiostereometric analyses at six visits over two years quantified implant migration for 200 cemented TKAs. Longitudinal data analysis examined the influence of postoperative tibial slope on implant migration (overall maximum total point motion (MTPM) migration and anterior-posterior tilt migration), accounting for age, sex, and body mass index. The correlations of tibial slope with one-year migration, continuous migration, and inducible displacements were also examined. Additionally, the amount of change in slope was compared to migration. RESULTS: The mean posterior tibial slope was 8.0° (standard deviation (SD) 3.8°) preoperatively and 3.8° (SD 3.1°) postoperatively, with a mean reduction in slope of 4.2° (SD 4.7°). Postoperative tibial slope (range 14.0° posterior slope to 3.4° anterior slope) was not associated with longitudinal overall migration (P = 0.671) or anterior-posterior tilt migration (P = 0.704). There was no association between postoperative tibial slope and migration at one year postoperatively (P = 0.441 for MTPM migration, P = 0.570 for tilt migration), change in migration from one to two years (P = 0.951), or inducible displacement (P = 0.970 MTPM, P = 0.730 tilt). The amount of change in tibial slope was also not associated with migration or inducible displacement. CONCLUSIONS: Residual and change in postoperative tibial slope were not associated with implant migration into tilt or overall migration, or inducible displacement for a single implant design. These findings support positioning tibial implants in a range of slopes, which may support patient-specific approaches to implant alignment.

Continuity of primary care and emergency department visits following knee and hip replacement surgery: a retrospective cohort study.

BACKGROUND: Continuity of primary care (CPC) improves patient well-being, but the association between CPC and surgical outcomes has not been well studied. The numbers of joint replacement procedures are expected to rise considerably in the coming years, so it is crucial to identify factors related to successful outcomes. The purpose of this study was to examine the association between CPC and emergency department (ED) visits after knee and hip replacement surgery. METHODS: Physician claims and hospital data from 2005 to 2020 in Nova Scotia were used in this retrospective study. To measure CPC, we used the Modified Modified Continuity Index (MMCI), which is the number of primary care providers adjusted for the total number of visits. The outcome was ED visits within 90 days of discharge. Logistic regression was used to test for associations between MMCI and the probability of an ED visit. RESULTS: There were 28 574 knee and 16 767 hip procedures in the data set; 13.9% (95% confidence interval [CI] 13.5%-14.3%) and 13.5% (95% CI 13.0%-14.0%) of the patients, respectively, had an ED visit within 90 days. For patients who underwent knee procedures, the mean MMCI was 0.868 (95% CI 0.867-0.870); 10.7% (95% CI 10.4 %-11.1 %) had perfect continuity of care. For patients who underwent hip procedures, the corresponding measures were 0.864 (95% CI 0.862-0.866) and 13.5% (95% CI 13.0%-14.0%). There was a statistically significant negative association between greater continuity of care and the probability of an ED visit after controlling for confounders. CONCLUSION: Having multiple primary care providers before surgery increased the likelihood of negative outcomes following knee or hip replacement surgery compared with having a single provider. Presurgical conversations should include primary care history to improve postsurgical outcomes.

Validation of a Surgical Objective Structured Clinical Examination (S-OSCE) Using Convergent, Divergent, And Trainee-Based Assessments of Fidelity.

OBJECTIVE: Describe the validation of a surgical objective structured clinical examination (S-OSCE) for the purpose of competency assessment based on the Royal College of Canada's Can-MEDS framework. DESIGN: A surgical OSCE was developed to evaluate the management of common orthopedic surgical problems. The scores derived from this S-OSCE were compared to Ottawa Surgical Competency Operating Room Evaluation (O-SCORE), a validated entrustability assessment, to establish convergent validity. The S-OSCE scores were compared to Orthopedic In-Training Examination (OITE) scores to evaluate divergent validity. Resident evaluations of the clinical encounter with a standardized patient and the operative procedure were scored on a 10-point Likert scale for fidelity. SETTING: A tertiary level academic teaching hospital. PARTICIPANTS: 21 postgraduate year 2 to 5 trainees of a 5-year Canadian orthopedic residency program creating 160 operative case performances for review. RESULTS: There were 5 S-OSCE days, over a 4-year period (2016-2019) encompassing a variety of surgical procedures. Performance on the S-OSCE correlated strongly with the O-SCORE (Pearson correlation coefficient 0.88), and a linear regression analysis correlated moderately with year of training (R²â€¯= 0.5345). The Pearson correlation coefficient between the S-OSCE and OITE scores was 0.57. There was a significant increase in the average OITE score after the introduction of the surgical OSCE. Resident fidelity ratings were available from 16 residents encompassing 8 different surgical cases. The average score for the overall simulation (8.0±1.6) was significantly higher than the cadaveric surgical simulation (6.5 ± 0.8) (p < 0.001) CONCLUSIONS: The S-OSCE scores correlate strongly with an established form of assessment demonstrating convergent validity. The correlation between the S-OSCE and OITE scores was less, demonstrating divergent validity. Although residents rank the overall simulation highly, the fidelity of the cadaveric simulation may need improvement. Administration of a surgical OSCE can be used to evaluate preoperative and intraoperative decision making and complement other forms of assessment.

Tibial Component Migration After Total Knee Arthroplasty With High-Viscosity Bone Cement.

BACKGROUND: High-viscosity (HV) bone cements have been formulated to offer potentially advantageous handling characteristics. However, alteration in the handling characteristics could influence implant fixation and survival. The primary objective of this study was to use radiostereometric analysis after total knee arthroplasty to assess the migration of the Triathlon tibial component fixed with HV cement (Simplex HV). METHODS: Twenty-three patients were followed for two years with radiostereometric analysis examinations at 6 visits. Migration was compared with published thresholds and with a control group from a previously published study from the same center using the same implants fixed with a medium viscosity cement. Inducible displacement was assessed, and Oxford 12 Knee Scores and satisfaction were recorded. RESULTS: Mean maximum total point motion migration reaching 0.40 mm (SD 0.16) at one year, and 0.41mm (SD 0.17) at two years, demonstrating a pattern of stable fixation, below published thresholds of acceptable migration, and not significantly different from the control group. One implant had continuous migration between 1 and 2 years but was clinically asymptomatic. Mean maximum total point motion inducible displacement measured at least one year postoperatively was 0.3 mm (SD 0.12). Mean Oxford 12 Knee Scores improved from 19 (SD 7) preoperatively to 42 (SD 8) 2 years postoperatively. CONCLUSIONS: The use of HV cement demonstrated an acceptable pattern of migration at 2 years, indicating low risk for aseptic loosening.

Prospective clinical study using radiostereometric analysis (RSA) to evaluate fixation of a modular cemented polished femoral stem.

BACKGROUND: The long-term clinical success of cemented polished tapered femoral components has been demonstrated in prospective as well as registry studies. This stem design type has also been well studied with radiostereometric analysis (RSA) and provides a standard to evaluate alternative designs of polished tapered cemented femoral components. This prospective study evaluates the subsidence of a polished cemented stem with a modular neck design utilising RSA. METHODS: 26 patients were prospectively enrolled in the study and 23 were available for RSA analysis at 2 years. RESULTS: The average subsidence of the femoral implant was 1.1 mm (SD 0.4 mm) at 2 years post operation. There were no revisions in this group, specifically no failures of the modular stem-neck design as has been seen with other implants. CONCLUSIONS: The RSA subsidence pattern at 2 years of this cemented femoral stem is similar to other successful designs with long-term follow-up. The implications over time of stem neck modularity for cemented polished tapered femoral components requires further evaluation.

Increased Mortality with the Use of Cementless Fixation for Femoral Neck Fractures: Analysis of 5883 Hip Arthroplasty Cases.

BACKGROUND: The use of cemented fixation for hip arthroplasty for femoral neck fractures has been advocated to limit the postoperative and intraoperative risk of periprosthetic fractures. However, there are concerns with the potential effects of cementing on patient mortality, particularly at the time of cementation. METHODS: This study examined the mortality rates of cemented compared to cementless hip arthroplasty fixation in a group of 5883 femoral neck fracture patients from 2001 to 2017. The data were derived from large administrative databases and census data. Confounders were identified and controlled with a multivariate analysis. The data were also stratified into 2 time frames, 2001-2008 and 2009-2017, to determine if there was an effect of more recent improvements in patient care or implant technology. RESULTS: Cemented fixation had a statistically significant reduction in mortality rates at 30, 90, and 365 days after surgery. There was no difference in mortality in 0, 1, or ≤7 days after discharge or during the admission. The mortality rate decreased but was still significantly increased with cementless fixation when the subjects were grouped from 2001 to 2008 and 2009 to 2017. CONCLUSION: Based on this evidence, the cemented fixation of hip arthroplasty should be considered for patients with femoral neck fractures.

Total cost of surgical site infection in the two years following primary knee replacement surgery.

OBJECTIVE: The disease burden of surgical site infection (SSI) following total knee (TKA) replacement is considerable and is expected to grow with increased demand for the procedure. Diagnosing and treating SSI utilizes both inpatient and outpatient services, and the timing of diagnosis can affect health service requirements. The purpose of this study was to estimate the health system costs of infection and to compare them across time-to-diagnosis categories. METHODS: Administrative data from 2005-2016 were used to identify cases diagnosed with SSI up to 1 year following primary TKA. Uninfected controls were selected matched on age, sex and comorbidities. Costs and utilization were measured over the 2-year period following surgery using hospital and out-of-hospital data. Costs and utilization were compared for those diagnosed within 30, 90, 180, and 365 days. A subsample of cases and controls without comorbidities were also compared. RESULTS: We identified 238 SSI cases over the study period. On average, SSI cases cost 8 times more than noninfected controls over the 2-year follow-up period (CaD$41,938 [US$29,965] vs CaD$5,158 [US$3,685]) for a net difference of CaD$36,780 (US$26,279). The case-to-control ratio for costs was lowest for those diagnosed within 30 days compared to those diagnosed later. When only patients without comorbidities were included, costs were >7 times higher. CONCLUSION: Our results suggest that considerable costs result from SSI following TKA and that those costs vary depending on the time of diagnosis. A 2-year follow-up period provided a more complete estimate of cost and utilization.

Developing and Assessing the Feasibility of Implementing a Surgical Objective Structured Clinical Skills Examination (S-OSCE).

OBJECTIVE: To1 describe the development and evaluate the feasibility of a surgical objective structured clinical examination (OSCE) for the purpose of competency assessment based on the Royal College of Canada's CanMEDS framework. DESIGN: A unique surgical OSCE was developed to evaluate the clinical and surgical management of common orthopaedic problems using simulated patients and cadaveric specimens. Cases were graded by degree of difficulty (less complex, complex, more complex) Developing an assessment tool with significant resource utilization and good correlation with traditional methods is challenging. The feasibility of an OSCE that evaluates independent clinical and surgical decision making was evaluated. In addition, as part of establishing construct validity, correlation of OSCE scores with previously validated O-scores was performed. SETTING: A tertiary level academic teaching hospital. PARTICIPANTS: Thirty-four Postgraduate year 3-5 trainees of a 5-year Canadian orthopedic residency program creating 96 operative case performances available for final review. RESULTS: The development of the OSCE cases involved a multistep process with attending surgeons, residents and a surgical education consultant. There were 4 different OSCE days, over a 3 year period (2016-2018) encompassing a variety of less complex and more complex procedures. Performance on the OSCE correlated strongly with the (O-SCORE, 0.89) and a linear regression analysis correlated moderately with year of training (r2 = 0.5737). The feasibility analysis demonstrated good financial practicality with solid programmatic integration. CONCLUSIONS: The unique surgical OSCE scores correlate strongly with an established entrustability scale. Administering this OSCE to evaluate preoperative and intraoperative decision making to complement other forms of assessment is feasible. The financial burden to training programs is modest in comparison to the insight gained by both residents and faculty.

Migration and Wear of a Dual Mobility Acetabular Construct at 3 Years Measured by Radiostereometric Analysis.

BACKGROUND: The anatomic dual mobility (ADM) acetabular component was introduced because of previously described low dislocation rates for this type of construct. The shape of the anatomic cup and the motion of polyethylene liner may have implications for acetabular cup fixation and polyethylene liner wear; therefore, the purpose of this study was to assess the migration patterns and wear rates of the ADM component using radiostereometric analysis. METHODS: Uncemented ADM acetabular components were implanted in 27 patients. Radiostereometric analysis exams were taken at 6 follow-up visits over 3 years. Proximal translation and sagittal rotation of the cup and polyethylene total wear and wear rates were calculated. Oxford 12 Hip scores and satisfaction were recorded. RESULTS: Mean proximal translation was below the 0.2 mm threshold at 2 years associated with acceptable long-term survivorship (0.16 mm [standard deviation {SD} 0.31] at 3 years). Mean sagittal rotation was 0.29 degrees (SD 1.03) and was greater in female subjects (P < .001). Following bedding-in, the annual wear rate was 0.02 mm/y, below the 0.1 mm/y threshold. There was no association between cup migration and polyethylene wear. Patient satisfaction at 3 years was 96%. Mean Oxford 12 Hip scores improved from 21 (SD 7) preoperatively to 43 (SD 7) 3 years postoperatively. CONCLUSIONS: The ADM cup demonstrated stable migration at 3 years indicating low risk for aseptic loosening. Bedding-in in the first year was followed by low annual wear rates. These finding suggest no increased risk of the dual mobility and anatomic design on fixation or wear.

Measuring Surgical Site Infection From Linked Administrative Data Following Hip and Knee Replacement.

BACKGROUND: Surgical site infections (SSIs) in hip and knee arthroplasty are increasing internationally. Current trends in SSI monitoring use single source administrative databases with data collection points commonly at 30 or 90 days. We hypothesize that SSI rates are being under-reported due to methodological biases. METHODS: Data from multiple administrative data sets were contrasted and compared to look at the 90-day SSI rates for hip and knee arthroplasty in a single province from 2001 to 2015. SSI rates were calculated over time by year, and the differences in infection rates between single and multiple administrative data sets were calculated as an estimate of under reporting rates of SSIs. Days until diagnosis was measured for those diagnosed with an infection within 1 year. RESULTS: Combining administrative data sets indicates that hospital-based data underestimate SSI rates by 0.44 (P < .0001) of a percentage point over all years, a clinically significant result given the overall infection rate of 2.2% over the period. Less than 50% of hip and knee arthroplasty was recorded as infected by 30 days and approximately 75% of cases were recorded as infected by 90 days. CONCLUSION: Single source administrative data sets and short follow-up periods underestimate SSI rates. Administrative data sets should be combined and a minimum follow-up period of 90 days should be used to more accurately track SSI rates in hip and knee arthroplasty.

Equivalent 2-year stabilization of uncemented tibial component migration despite higher early migration compared with cemented fixation: an RSA study on 360 total knee arthroplasties.

Background and purpose - Thresholds of implant migration for predicting long-term successful fixation of tibial components in total knee arthroplasty have not separated cemented and uncemented fixation. We compared implant migration of cemented and uncemented components at 1 year and as the change in migration from 1 to 2 years. Patients and methods - Implant migration of 360 tibial components measured using radiostereometric analysis was compared at 1 year and as the change in migration from 1 to 2 years in 222 cemented components (3 implant designs) and 138 uncemented components (5 implant designs). Results - 1-year maximum total point motion was lower for the cemented tibial components compared with the uncemented components (median = 0.31 mm [0.03-2.98] versus 0.63 mm [0.11-5.19] respectively, p < 0.001, mixed model). The change in migration from 1 to 2 years, however, was equivalent for cemented and uncemented components (mean [SD] 0.06 mm [0.19] and 0.07 mm [0.27] mm respectively, p = 0.6, mixed model). Interpretation - These findings suggest that current thresholds of acceptable migration at 1 year may be better optimized by considering cemented and uncemented tibial components separately as higher early migration of uncemented components was not associated with decreased stability from 1 to 2 years.