The Impact of Surgeon Volume on Unicompartmental Knee Arthroplasty Survivorship: A Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI) Database Analysis.

BACKGROUND: The utilization of unicompartmental knee arthroplasty (UKA) has remained low when compared to total knee arthroplasty (TKA), possibly due to higher rates of revision and reoperation. This study aimed to quantify surgeon UKA case-volumes and measure the effect of surgeon volume on early revision. We hypothesized that surgeons who have high case volumes would have lower revision rates compared to medium- and low-volume surgeons. METHODS: Primary UKAs were performed between February 2012 and November 2021, and associated revisions were identified utilizing the Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI). Surgeon information, including total cases and annual UKA volume, was collected. Case volume per year was stratified as High (≥ 35 cases per year), Medium (15 to 34 cases per year), and low (< 15 cases per year). RESULTS: There were a total of 15,542 UKAs performed. Of these, 701 (4.5%) were revised, and 412 (58.8%) revisions occurred within 2 years. Of the 287 surgeons who performed an UKA in the registry, 237 (82.6%) were low-volume surgeons, 36 (12.5%) were medium-volume, and 14 (4.9%) were high-volume. High-volume surgeons were more likely to operate on older patients (P < 0.01), Medicare patients (P < 0.01), and patients who had ASA (American Society of Anesthesiologists) scores of III and IV (P < 0.01). High-volume surgeons had significantly lower 5-year revision rates compared to medium and low-volume surgeons (high: 4.3% (95% CI [confidence interval]: 3.70 to 4.90), medium: 5.2% (4.44 to 6.12), low: 7.2% (6.37 to 8.02); P < 0.001). In comparison, the 5-year revision rate for TKA in Michigan was 3.0% (95% CI: 2.90 to 3.08). CONCLUSION: When UKAs were performed by high-volume surgeons in the state of Michigan, there was better survivorship when compared to low-volume and medium-volume surgeons. High-volume surgeons were more likely to perform UKA on older patients, Medicare patients, and patients who had ASA scores of III and IV. The revision rate for the high-volume surgeons still exceeded the 5-year revision rate for total knee arthroplasty in Michigan.

Early Survivorship of Uncemented Total Knee Arthroplasty Varies by Age and Sex Based on Data From the Michigan Arthroplasty Registry Collaborative Quality Initiative.

BACKGROUND: Outcome data for newer uncemented total knee arthroplasty (TKA) designs has been mixed. Registry studies showed worse survivorship, but clinical trials have not demonstrated differences compared to cemented designs. There has been renewed interest in uncemented TKA with modern designs and improved technology. The utilizations of uncemented knees in Michigan, 2-year outcomes, and the effects of age and sex were evaluated. METHODS: A statewide database from 2017 through 2019 was analyzed for incidence, distribution, and early survivorship of cemented versus uncemented TKAs. There was 2-year minimum follow-up. Kaplan-Meier survival analysis was used to generate time to first revision cumulative percent revision curves. The impacts of age and sex were examined. RESULTS: Use of uncemented TKAs increased from 7.0 to 11.3%. Uncemented TKAs were more commonly men, younger, heavier, American Society of Anesthesiologists score > 2, and opioid users (P < .05). At 2 years, overall cumulative percent revision was higher in uncemented (2.44% [2.00, 2.99]) versus cemented (1.76% [1.64, 1.89]), particularly in women uncemented (2.41 [1.87, 3.12]) versus cemented (1.64 [1.50, 1.80]). Revision rates were greater with uncemented women >70 years (1.2% 1 year, 1.02% 2 years) versus < 70 years (0.56%, 0.53%), notably uncemented were inferior in both groups (P < .05). Men, regardless of age, had similar survivorships with both cemented and uncemented designs. CONCLUSION: The use of an uncemented TKA had an increased risk of early revision compared to cemented. This finding, however, was only apparent in women, especially those >70 years old. Surgeons should consider cement fixation in women >70 years.

Are Short Stems Associated With Higher Fracture Rates and Early Revision Rates in Primary Total Hip Arthroplasty? A Noninferiority Analysis.

BACKGROUND: This study aimed to determine if "short" femoral stems were noninferior to (at least as good as) standard-length stems in regards to 90-day periprosthetic fracture and 1-year revision rates. METHODS: Using the MARCQI implant registry, a retrospective study of statewide data was carried out on 64,084 total hip arthroplasties (THAs) between 2012 and 2017. We noticed an increase in the use of "short" uncemented femoral hip stems during THA. Chi-square tests were used to test homogeneity of categorical variables. The covariates included in the analyses were identified using modern epidemiological methods. A Type I probability of 0.05 was used as the level of statistical significance. Inverse probability of treatment weighting (IPTW) was used to mitigate confounding variables. RESULTS: One hundred and seven stems were implanted by surgeons in the state of Michigan. They were classified according to the Khanuja Classification System as Type 2A (trapezoidal, double-tapered calcar loading, n = 3,281), Type 3 (calcar loading with lateral flare, n = 1,898), and Type 4 (shortened, tapered, conventional, n = 19,580), and were compared to standard-length, type 5, stems (n = 33,322) in regards to the 2 outcomes (periprosthetic fractures and 1-year revision rates). Overall, 1-year revision and the 90-day fracture rates were 1.3% (791/57,853) and 1.1% (631/57,968), respectively. Noninferiority was established for all short stems at the clinical threshold of an odds ratio (OR) of 1.5 with P-values <0.05 for 90-day fractures. In regards to 1-year revision rates, noninferiority was also established for Type 3 and 4 stems (P < .05). CONCLUSION: The increased use of "short stems" in Michigan did not lead to increased 1-year revision or 90-day fracture rates.

Index surgery and ninety day re-operation cost comparison of robotic-assisted versus manual total knee arthroplasty.

INTRODUCTION: This study looks to compare early costs of index surgery and re-operations of robotic-assisted total knee arthroplasties (rTKA) and manual total knee arthroplasty (mTKA) re-operations within 90 days. MATERIAL AND METHODS: The Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI) database was queried for patients undergoing rTKA and mTKA at our institution from January 1st, 2018, to March 31st, 2021. Primary outcomes were the day of surgery and overall encounter variable direct costs (VDC). Secondary outcomes included 90-day re-operations and costs. RESULTS: One thousand two hundred seventy-six (21.2%) patients were in the rTKA cohort, while 4740 (78.8%) were in the mTKA cohort. When comparing rTKA to mTKA, rTKA had higher median total encounter costs (p < 0.001) and higher encounter VDC costs (p < 0.001). TKA had higher day of surgery total VDC (p < 0.001), VDC supplies (p < 0.001), and VDC of post-op recovery (p < 0.001). Multivariate linear regression showed no relationship with age, BMI, OR time, or LOS with cost for rTKA or mTKA. CONCLUSION: Results from our study show that rTKA is associated with a higher index surgery costs, and no difference in 90-day re-operation costs. The main factor driving increased cost is supply cost, with other variables between too small in difference to make a significant financial impact. Future studies should focus on post-operative costs including readmission and episode of care costs and should consider cost to the payor as opposed to VDC. rTKA will become more common, and other institutions may need to take a closer financial look at this more novel instrumentation before adoption. LEVEL OF EVIDENCE: III, retrospective cohort.

How Do Preoperative Medications Influence Outcomes After Total Joint Arthroplasty?

BACKGROUND: Recent health care policy changes require hospitals and physicians to demonstrate improved quality. In 2012, a prospective database was formed with the Blue Cross and Blue Shield of Michigan to improve quality of care. The purpose of this study was to analyze patient preoperative medication as predictors of outcomes after total joint arthroplasty. METHODS: Data were collected on patient's preoperative medications from 2012 to 2015 using a total joint arthroplasty database. Medications were categorized as antiplatelet, antimicrobial, anticoagulant, narcotic, steroid, insulin, or oral diabetes medication. Outcomes included hospital length of stay (LOS), discharge disposition/destination, and 90-day readmission. Univariate and multivariate regression analyses were performed. RESULTS: A total of 3959 patients were studied. Eighty percent (3163 patients) were discharged home. The remainder (795) went to an extended-care facility (ECF). Patients discharged to an ECF were taking more medications (1.13 vs 0.80 in total knee arthroplasty; 1.18 vs 0.83 in total hip arthroplasty; P <.001). Patients who were readmitted took more medications (1.0 vs 0.85; P <.01). There were more discharges to an ECF in narcotic, steroid, and diabetes medication users. Patients taking anticoagulants, narcotics, insulin, and antiplatelets had greater readmission rates. There was a significant correlation between the number of medications and an increased LOS. CONCLUSION: Patients taking more medications were more frequently discharged to an ECF and had increased LOS and readmission rates. Narcotics and diabetic medications had the greatest influence. Category and quantity of preoperative medications can be used as predictors of outcomes after arthroplasty surgery.