Does Resurfacing the Patella Increase the Risk of Extensor Mechanism Injury Within the First Two Years After Total Knee Arthroplasty?

Background Extensor mechanism injury (EMI) following total knee arthroplasty (TKA) is a potentially catastrophic complication and may lead to significant morbidity or need for revision reconstructive procedures. Patella resurfacing (PR), while commonly performed during TKA, reduces overall patella bone stock and may increase the risk of EMI after TKA. The purpose of this study was to assess if patellar resurfacing (PR) in elderly patients raises the risk for subsequent EMI. Methods The American Joint Replacement Registry (AJRR) was queried to identify Medicare patients ≥65 years old undergoing primary elective TKA for osteoarthritis between January 2012 and March 2020. Patient age, sex, and Charlson Comorbidity Index (CCI) were collected. Records were subsequently merged with Medicare claims records and evaluated for the occurrence of patella fracture, quadriceps tendon rupture, or patellar tendon rupture based on ICD-9/10 diagnosis codes within 2 years of TKA. Patients were stratified based on whether PR occurred or not (NR). Logistic regression was used to determine the association between PR and EMI. Results A total of 453,828 TKA were eligible for inclusion and 428,644 (94.45%) underwent PR. The incidence of PR decreased from 96.06% in 2012 to 92.35% in 2022 (p<0.001). Patients undergoing PR were more often female (60.93% vs 58.50%; p<0.001) and had a lower mean CCI (3.09 [1.10] vs. 3.16 [1.20]; p<0.001). Odds for EMI did not differ based on whether PR was performed (OR: 0.85 [0.65-1.11]; p=0.2246). Increasing age (OR: 1.06 [1.05-1.07], p<0.0001]) and CCI (OR: 1.06 [0.95-1.19], p=0.0009) were associated with EMI. Conclusions PR is commonly performed during TKA in the United States and was not found to increase odds for EMI within 2 years of TKA in patients ≥65 years old. Increased age and medical comorbidity were associated with higher odds for subsequent EMI.

Fragility Index Analysis of the 2018 Clinical Practice Guidelines on Tranexamic Acid Use in Total Joint Arthroplasty.

BACKGROUND: The 2018 American Association of Hip and Knee Surgeons clinical practice guideline (CPG) 'Tranexamic Acid Use in Total Joint Arthroplasty' evaluated the efficacy and safety of tranexamic acid in primary total joint arthroplasty. The following review assessed the statistical fragility of the randomized controlled trial (RCT) outcomes on which the CPG recommendations were based using a fragility analysis. METHODS: All dichotomous outcomes from the randomized controlled trials used to guide the CPG from its associated network and direct meta-analyses were analyzed. Fragility and reverse fragility indices (FI and rFI) and quotients (FQ and rFQ) were calculated for each outcome. Mean indices and quotients were calculated for each guideline question, outcome category, and comparison of tranexamic dose, formulation, and administration timing. RESULTS: This review evaluated 403 dichotomous outcomes on transfusion and complication rates associated with tranexamic acid (TXA) administration. The mean FI of significant outcomes of the CPG was 5.23, and the mean rFI of nonsignificant outcomes was 5.80. Outcomes assessing complication rates had a mean rFI of 6.48. Most outcomes on transfusion in categories comparing TXA to placebo administration had higher mean FIs than rFIs, and all outcomes comparing transfusion risk associated with different TXA formulations and doses had higher mean rFIs than FI or no associated significant outcomes. CONCLUSION: The rFI and FIs calculated for this CPG are comparable to or higher than mean values reported across orthopaedic literature, indicating the relative statistical stability of its included outcomes. As we learn more about fragility analyses and their potential applications, this type of statistical analysis shows promise as a useful tool to incorporate into future guidelines to assess the quality of RCTs and evaluate the strength of recommendations.

Improvements in Noise Symptoms, Forgotten Joint Scores, and Functional Outcomes With Greater Time Following Total Knee Arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA) is an impactful procedure with goals that include pain reduction and improved function, with low levels of prosthesis awareness. The purpose of this study was to determine if patients reported prosthetic noise and noise-related symptoms diminished over the course of time after TKA. METHODS: This study was a single institutional, retrospective study of patients who underwent primary unilateral TKA from 2018 to 2021. The TKAs were performed by four high-volume, fellowship-trained arthroplasty surgeons. Patients had similar baseline characteristics. Patients completed a survey consisting of four Likert scale questions related to prosthetic noise generation, the Forgotten Joint Score, and the Knee Injury and Osteoarthritis Outcome Score-Joint Replacement. Data were compared between patients who had undergone TKA one to two years earlier (N = 305) and those who had TKA three to four years prior to evaluation (N = 177). RESULTS: After more time with TKA, patients had significantly lower reports of hearing noise (31.1 versus 43.6%; P = 0.009) and feeling prosthetic noise-related symptoms (28.2 versus 40.3%; P = 0.010). Furthermore, after more time from TKA, patients had significantly higher satisfaction regarding noise-generation (65.5 versus 50.2%; P = 0.012), postoperative Knee Injury and Osteoarthritis Outcome Score-Joint Replacement scores (80.9 versus 75.9; P = 0.005), and Forgotten Joint Scores (65.4 versus 53.8; P < 0.001). CONCLUSIONS: As more time passes after TKA, patients observe less prosthetic noise generation and have lower levels of prosthesis awareness and greater satisfaction than those who had surgery more recently. It is unclear whether these differences represent real improvement or acclimation to noise over time.

Fragility analysis and systematic review of patellar resurfacing versus non-patellar resurfacing in total knee arthroplasty.

Introduction: Fragility analysis is a method of further characterising the robustness of statistical outcomes. This study evaluates the statistical fragility of randomised controlled trials (RCTs) comparing patellar resurfacing versus non-patellar surfacing in total knee arthroplasty (TKA). Methods: PubMed, MEDLINE and EMBASE were searched for RCTs comparing outcomes in TKA based on patellar resurfacing. Fragility index (FI) and reverse FI (collectively, "FI") were calculated for dichotomous outcomes as the number of outcome reversals needed to change statistical significance. Fragility quotient (FQ) was calculated by dividing the FI by the sample size for that outcome. Median FI and FQ were calculated for each individual outcome and for the overall study. Subanalyses were performed to assess FI and FQ based on outcome type, statistical significance and loss to follow-up. Results: Twenty-one RCTs were included in the analysis, capturing 3910 subjects. The overall median FI was 5.0 (interquartile range, [IQR] 4.0-6.0), and the overall median FQ was 0.048 (IQR 0.022-0.065). The outcome of anterior knee pain has a median FI of 6.0 (IQR 4.0-6.0) and a median FQ of 0.057 (IQR 0.025-0.065). Only five (7%) outcomes were significant. The loss to follow-up was greater than the FI in 12 of 19 studies (63%) with available data. Conclusion: RCTs comparing patellar resurfacing in TKAs show significant statistical fragility; a few outcome reversals can alter findings. The majority of outcomes were nonsignificant, indicating that the choice to resurface the patella may not affect most clinical outcomes; however, clinical conclusions are limited by the statistical fragility of the analysed outcomes. Larger RCTs for this comparison are necessary, and we suggest adding FI and FQ to RCT reports with p values to improve the interpretability of results. Level of Evidence: Level II.

Low-Dose Enteric-Coated and Chewable Aspirin Are Not Equally Effective in Preventing Venous Thromboembolism in Total Knee and Hip Arthroplasty.

BACKGROUND: Low-dose aspirin is an effective venous thromboembolism (VTE) prophylactic medication in primary total joint arthroplasty, but the efficacy and safety of the formulations of chewable and enteric-coated aspirin have not been compared. The purpose of this study was to investigate the VTE and gastrointestinal (GI) complication rates of chewable and enteric-coated 81 mg aspirin bis in die for VTE prophylaxis in primary total joint arthroplasty. METHODS: A retrospective, single-institution cohort study was performed on patients who underwent primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) from 2017 to 2021. Comparisons were made between 4,844 patients who received chewable, noncoated aspirin 81 mg and 4,388 patients who received enteric-coated 81 mg aspirin. Power analysis demonstrated 1,978 and 3,686 patients were needed per group to achieve a power of 80% for 90-day VTE rates (using inferiority testing) and GI complications (using superiority testing), respectively. Patients had similar baseline characteristics. Statistical analyses were done using t-tests and Chi-squared tests, with statistical significance defined as a P value < .05. RESULTS: There were no significant differences in the incidences of postoperative VTE (0.31% versus 0.55%; P = .111) or GI complications (0.14% versus 0.14%; P = 1.000) between patients who received either chewable or enteric-coated 81 mg aspirin bis in die in the overall comparison that included both THA and TKA patients combined, or THA patients alone. However, the VTE incidence for TKA patients alone was significantly lower with chewable than enteric-coated aspirin (0.22% versus 0.62%; P = .037), with no difference in GI complications (0.13% versus 0.19%; P = .277). CONCLUSIONS: Low-dose aspirin in enteric-coated formulation is inferior to chewable aspirin for VTE prophylaxis in primary TKA, but not inferior in THA patients. Both formulations have a similar GI complication rate. Therefore, it is reasonable to consider a transition from enteric-coated to uncoated chewable low-dose aspirin.

Surgeons Experience Greater Physiologic Stress and Strain in the Direct Anterior Approach Than the Posterior Approach for Total Hip Arthroplasty.

BACKGROUND: The direct anterior approach (DAA) and posterior approach (PA) for total hip arthroplasty (THA) have advantages and disadvantages, but their physiologic burden to the surgeon has not been quantified. This study was conducted to determine whether differences exist in surgeon physiological stress and strain during DAA in comparison to PA. METHODS: We evaluated a prospective cohort of 144 consecutive cases (67 DAA and 77 PA). There were 5, high-volume, fellowship-trained arthroplasty surgeons who wore a smart-vest that recorded cardiorespiratory data while performing primary THA DAA or PA. Heart rate (beats/minute), stress index (correlates with sympathetic activations), respiratory rate (respirations/minute), minute ventilation (L/min), and energy expenditure (calories) were recorded, along with patient body mass index and operative time. Continuous data was compared using t-tests or Mann Whitney U tests, and categorical data was compared with Chi-square or Fischer's exact tests. RESULTS: There were no differences in patient characteristics. Compared to PA, performing THA via DAA had a significantly higher surgeon stress index (17.4 versus 12.4; P < .001), heart rate (101 versus 98.3; P = .007), minute ventilation (21.7 versus 18.7; P < .001), and energy expenditure per hour (349 versus 295; P < .001). However, DAA had a significantly shorter operative time (71.4 versus 82.1; P = .001). CONCLUSIONS: Surgeons experience significantly higher physiological stress and strain when performing DAA compared to PA for primary THA. This study provides objective data on energy expenditure that can be factored into choice of approach, case order, and scheduling preferences, and provides insight into the work done by the surgeon.

Debridement, Antibiotics, and Implant Retention in Unicompartmental Knee Arthroplasty Infection.

BACKGROUND: This multicenter study sought to further investigate the method and outcome of debridement, antibiotics, and implant retention (DAIR) for the management of unicompartmental knee periprosthetic joint infection (PJI). METHODS: This retrospective study was performed on 52 patients who underwent DAIR for PJI of a unicompartmental knee arthroplasty (UKA) across 4 academic medical centers, all performed by fellowship-trained arthroplasty surgeons. Patient demographics, American Society of Anesthesiologists score, infecting organism, operative data, antibiotic data, and success in infection control at 1 year were collected. RESULTS: The average time from index surgery to diagnosis of PJI was 11.1 weeks (range, 1.4 to 48). There was no correlation between time of diagnosis and success at 1 year (R = 0.09, P = .46). There was an association between surgical synovectomy and the eradication of infection (R = 0.28, P = .04). Overall, there was an 80.8% (42 of 52) infection-controlled success rate at 1 year from the DAIR procedure. All DAIR failures went on to require another procedure, either 1-stage (2 of 10) or 2-stage (8 of 10) revision to total knee arthroplasty (TKA). Of the DAIR successes, 6 (14.3%) went on to require conversion to TKA for progression of arthritis within 5 years. CONCLUSIONS: This study demonstrates that DAIR is a safe and moderately effective procedure in the setting of acute PJI of UKA across institutions, with a success rate consistent with DAIR for TKA. The data suggest that a wide exposure and thorough synovectomy be incorporated during the DAIR UKA to improve the likelihood of successful eradication of PJI at the 1-year mark. LEVEL OF EVIDENCE: Level III.

Return to Sport After Unicompartmental Knee Arthroplasty and Patello-Femoral Arthroplasty.

BACKGROUND: Data on sports/physical activity participation following unicompartmental knee arthroplasty (UKA) and patello-femoral arthroplasty (PFA) is variable and limited. The purpose of this study was to assess participations, outcomes, and limitations in sports following UKA and PFA. METHODS: Patients who underwent UKA and PFA at a single institution from 2015 to 2020 were surveyed on sports participation before and after surgery. Data was correlated with perioperative patient characteristics and outcome scores. Among 776 patients surveyed, 356 (50%) patients responded. Of respondents, 296 (83.1%) underwent UKA, 44 (12.6%) underwent PFA, and 16 (4.5%) underwent both UKA/PFA. RESULTS: Activity participation rates were 86.5, 77.3, and 87.5% five years prior, and 70.9, 61.4, and 75% at one year prior to UKA, PFA, and UKA/PFA, respectively. Return to sports rates were 81.6, 64.7, and 62.3% at mean 4.6 years postoperatively, respectively. The most common activities were recreational walking, swimming, cycling, and golf. Patients returned to a similar participation level for low-impact activities, whereas participation decreased for intermediate- and high-impact activities. Patients participating in activities had higher postoperative Knee Injury and Osteoarthritis Outcome Score Joint Replacement (P < .001), 12-Item Short Form Physical Component Score (P = .045) and Mental Component Score (P = .012). Activity restrictions were reported among 25, 36.4, and 25% of UKA, PFA, and UKA/PFA patients, respectively, and were more commonly self-imposed than surgeon-directed. CONCLUSIONS: Though UKA patients' postoperative sports participation may improve compared to one year preoperatively, participation for patients surgically treated for isolated osteoarthritis is decreased compared to 5 years preoperatively and varies among patient subsets.

The Efficacy of Preoperative Video-Based Opioid Counseling on Postoperative Opioid Consumption After Total Knee Arthroplasty: A Prospective Randomized Controlled Trial.

BACKGROUND: There are myriad strategies to reduce opioid consumption after total knee arthroplasty (TKA). Recent studies have suggested that preoperative counseling may reduce opioid use after a variety of orthopedic procedures. The purpose of this study was to investigate whether preoperative video-based patient education regarding opioid use and abuse reduces opioid consumption after TKA. METHODS: In this prospective randomized controlled trial, patients were randomized before TKA to either receive preoperative video-based counseling or not. Counseling involved a pretaped 5-minute video that educated patients on statistics regarding the "opioid epidemic" and discussed safe use and alternatives to opioids after TKA. There were no significant differences in baseline patient demographics between groups. All patients received a similar multimodal perioperative pain management protocol and completed a daily diary for 2 weeks postoperatively. Diary records measured pain levels using a visual analog score, opioid consumption, side effects experienced, and patient opinion and satisfaction regarding their pain control. RESULTS: Patients in the counseling group consumed significantly less morphine milligram equivalents on postoperative days 0 to 3 (78.8 versus 106.1, P = .020) and in week one postoperatively (129.9 versus 180.7, P = .028), with a trend of less consumption over 2 weeks postoperatively (186.9 versus 239.1, P = .194). There were no significant differences in the number of patients requiring refills, side effects, or daily pain levels between the 2 groups. CONCLUSIONS: This study found significantly decreased opioid consumption within the first week after TKA in patients who received preoperative video counseling.

Interpreting the Current Literature on Outcomes of Robotic-Assisted Versus Conventional Total Knee Arthroplasty Using Fragility Analysis: A Systematic Review and Cross-Sectional Study of Randomized Controlled Trials.

BACKGROUND: Fragility analysis is a method of further characterizing outcomes in terms of the stability of statistical findings. This study assesses the statistical fragility of recent randomized controlled trials (RCTs) evaluating robotic-assisted versus conventional total knee arthroplasty (RA-TKA versus C-TKA). METHODS: We queried PubMed for RCTs comparing alignment, function, and outcomes between RA-TKA and C-TKA. Fragility index (FI) and reverse fragility index (RFI) (collectively, "FI") were calculated for dichotomous outcomes as the number of outcome reversals needed to change statistical significance. Fragility quotient (FQ) was calculated by dividing the FI by the sample size for that outcome event. Median FI and FQ were calculated for all outcomes collectively as well as for each individual outcome. Subanalyses were performed to assess FI and FQ based on outcome event type and statistical significance, as well as study loss to follow-up and year of publication. RESULTS: The overall median FI was 3.0 (interquartile range, [IQR] 1.0 to 6.3) and the median reverse fragility index was 3.0 (IQR 2.0 to 4.0). The overall median FQ was 0.027 (IQR 0.012 to 0.050). Loss to follow-up was greater than FI for 23 of the 38 outcomes assessed. CONCLUSIONS: A small number of alternative outcomes is often enough to reverse the statistical significance of findings in RCTs evaluating dichotomous outcomes in RA-TKA versus C-TKA. We recommend reporting FI and FQ alongside P values to improve the interpretability of RCT results.

Completion of Patient-Reported Outcome Measures Improved With Use of a Mobile Application in Arthroplasty Patients: Results From a Randomized Controlled Trial.

BACKGROUND: The collection of patient-reported outcome measures (PROMs) has historically been reported as costly and time-consuming, with low compliance rates that may impact reimbursement. Little research has reported the effects of mobile applications to support PROMs collection following arthroplasty. METHODS: Secondary analysis of data from a multicenter randomized controlled trial was performed. Patients undergoing knee and hip arthroplasty were randomized to utilize a smartphone-based care management platform (app) for self-directed rehabilitation and completed joint-specific PROMs (Hip Dysfunction and Osteoarthritis Outcome Score, Joint Replacement or Knee Injury and Osteoarthritis Score, Joint Replacement) via the application at prescribed intervals or on paper during clinic visits. Control patients received practice standard of care, and completed PROMs via emailed hyperlink or during clinic visits following lower limb arthroplasty. Overall, 455 patients underwent knee arthroplasty procedures (245 control, 210 app group) and 380 underwent total hip arthroplasty (206 control, 174 app group). Compliance with expected PROMs completion was calculated through one year postoperatively. RESULTS: Compliance was higher in the app group preoperatively in both knee (98.1 versus 86.9%, P < .0001) and hip cohorts (96.0 versus 88.4%, P = .008), and postoperatively, including at one year (knees, 72.2 versus 53.7%, P < .0001; hips, 71.1 versus 49.2%, P < .0001). On log-binomial regressions, intervention arm was the strongest predictor of completion of all PROMs, where app users undergoing knee (Relative Risk 2.039, 95% confidence interval (CI) 1.595 to 2.607, P < .000) and hip arthroplasty (2.268 95% CI 1.742 to 2.953, P < .0001) were more likely to be compliant at all timepoints. The majority of patients in the app group, including those over 65 years of age, completed PROMs using the application as opposed to paper methods. CONCLUSIONS: A smartphone mobile application that engages patients during recovery after knee and hip joint arthroplasty improved compliance with completion of preoperative and postoperative PROMs compared to other electronic and paper methods.

Association Between Digitally Provided Education and 90-Day Return to Sexual Activity Following Total Knee Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: Contemporary total knee arthroplasty patients have increased expectations of returning to predisease function, including sexual activity (SA). The purpose of this study was to determine whether patients using a digital care management platform (DCMP) were more likely to have a higher rate and frequency of return to SA. METHODS: We conducted an exploratory analysis of a prospective, multicenter, randomized controlled trial that enrolled patients undergoing total knee arthroplasty. A total of 304 patients were randomized to a DCMP (n = 119) providing preoperative and postoperative education regarding return to SA or standard postoperative care (control group; n = 185). Return to SA, assessed via questionnaire, patient-reported outcome measures, Timed Up and Go test, single leg stance, active range of motion and need for manipulation under anesthesia were assessed at 90 days postoperatively. RESULTS: More patients in the DCMP group returned to SA compared to control at 90 days (58.4 versus 39.6%, P = .018); however, the control group resumed SA sooner (33.1 versus 42.0 days, P = .023). Patients who returned to SA were younger (61.6 versus 65.9 year), more often men (56 versus 35%) (P < .001), higher performing on the Timed Up and Go and single leg stance tests (P < .001), and had greater active range of motion (P = .007). There were no differences in patient-reported outcome measures or need for manipulation under anesthesia between patients that returned to SA and those who did not. CONCLUSIONS: More patients using a DCMP resumed SA at 90 days; however, patients in the control group returned to SA sooner. Those who returned to SA were younger, possessed greater physical function, and were more often men.

Joint line position change in primary total knee arthroplasty: a radiographic analysis comparing conventional and robotic techniques.

PURPOSE: Joint line (JL) position change in total knee arthroplasty (TKA) may alter knee biomechanics and impact function. The purpose of this study was to compare the change in JL position between robotic-assisted TKA (RA-TKA) and conventional TKA (C-TKA). METHODS: A retrospective, radiographic analysis was conducted of patients who underwent RA-TKA and C-TKA to compare JL position change. JL position was measured in consecutive RA-TKAs and C-TKAs performed by four fellowship-trained arthroplasty surgeons. Statistical analysis was done utilizing t-tests and Mann Whitney U tests, with statistical significance being defined as a p value < 0.05. RESULTS: Six hundred total RA-TKAs and 400 total C-TKAs were included in the analysis. There were no significant differences in patient baseline characteristics such as body mass index, range of motion, and tibiofemoral coronal alignment. RA-TKAs were associated with an average of 0.04 (2.2) mm JL position change, and C-TKAs were associated with an average 0.5 (3.2) mm JL position change (p = 0.030). There were inter-surgeon differences when comparing the change in JL position for RA-TKAs and C-TKAs between the four participating surgeons. CONCLUSION: RA-TKA leads to better preservation of the JL position than C-TKA, and this seems to be dependent on the arthroplasty surgeon's preferences and techniques during TKA. Whether this statistically significant difference is clinically relevant needs to be further investigated.

Robotic-Assisted Total Knee Arthroplasty Has Similar Rates of Prosthetic Noise Generation as Conventional Total Knee Arthroplasty.

Background: Noise has been reported to occur with relatively high frequency after conventional total knee arthroplasty (C-TKA), and this may impact the incidence of patient satisfaction and function. The purpose of this study was to compare the rate of patient-reported prosthetic noise generation after robotically-assisted TKA (RA-TKA) and C-TKA. Methods: A retrospective study was conducted of unilateral primary RA-TKAs and C-TKAs performed between 2018 and 2021. Patients completed a survey consisting of 4 Likert scale questions related to prosthetic noise generation and Knee Injury and Osteoarthritis Score Joint Replacement and Forgotten Joint Score were assessed prospectively preoperatively and at a minimum of 1-year of clinical follow-up. Statistical analysis was done utilizing T-tests and chi-square tests, with statistical significance defined as a P-value < .05. Results: One hundred sixty-two RA-TKAs and 320 C-TKAs with similar baseline characteristics and functions were included. There were no significant differences in hearing or feeling grinding, popping, clicking, or clunking (40.7% vs 38.1%; P = .647) between groups. Most RA-TKAs and C-TKAs were not dissatisfied regarding noise generation (70.4% vs 73.1%; P = .596). In both cohorts, patients who reported noise generation had lower average Forgotten Joint Scores (45.5 vs 66.1; P < .001) and lower postoperative Knee Injury and Osteoarthritis Score Joint Replacement scores (72.0 vs 81.4; P < .001) than those who did not experience noise generation. Conclusions: While RA-TKA may facilitate soft tissue balancing, there were no differences in prosthetic noise generation between RA-TKA and C-TKA. However, those who experience implant-generated noise have lower functional outcome scores.

Robotic-Assisted Total Knee Arthroplasty: What are Patients' Perspectives, Understanding and Expectations?

BACKGROUND: The rate of using robotic-assisted total knee arthroplasty (RA-TKA) has increased markedly. Understanding how patients view the role of robotics during total knee arthroplasty (TKA) informs shared decision making and facilitate efforts to appropriately educate patients regarding the risks and benefits of robotic assistance. METHODS: A self-administered questionnaire was completed by 440 potential TKA patients at the time of their surgery scheduling. Participants answered 25 questions regarding RA-TKA, socioeconomic factors, and their willingness to pay (WTP) for RA-TKA. Logistic regressions were used to determine if population characteristics and surgeon preferences influenced the patients' perceptions of RA-TKA. RESULTS: There were 39.7% of respondents who said that they had no knowledge regarding RA-TKA. Only 40.7% of participants had expressed a desire for RA-TKA to be used. There were 8.7% who were WTP extra for the use of RA-TKA. Participants believed that the main 3 benefits of RA-TKA compared to conventional methods were: more accurate implant placement (56.2%); better results (49.0%); and faster recovery (32.1%). The main 3 patient concerns were harm from malfunction (55.2%), reduced surgeon role in the procedure (48.1%), and lack of supportive research (28.3%). Surgeon preference of RA-TKA was associated with patient's willingness to have RA-TKA (odds ratio 4.60, confidence interval 2.98-7.81, P < .001), and with WTP extra for RA-TKA (odds ratio 2.05, confidence interval: 1.01-4.26, P = .049). CONCLUSION: Patient knowledge regarding RA-TKA is limited. Nonpeer-reviewed online information may make prospective TKA candidates vulnerable to misinformation and aggressive advertising. The challenge for orthopaedic surgeons is to re-establish control and reliably educate patients about the proven advantages and disadvantages of this emerging technology.

Unicompartmental Knee Arthroplasty Is Cost-Effective in an Outpatient Setting.

INTRODUCTION: Increasingly, unicompartmental knee arthroplasty (UKA) is being performed on an outpatient basis, with the growing utilization of ambulatory surgery centers (ASCs). The purpose of this study was to compare the costs of UKAs performed in an ASC to UKAs done in a hospital, either on an outpatient or inpatient basis. METHODS: This study involved three matched groups, each with 50 consecutive patients, undergoing UKA either on an outpatient basis in an ASC or a community hospital, or who were admitted overnight to the same community hospital. Identical perioperative analgesic regimens and care protocols were used in each group. The primary outcomes evaluated included direct facility costs. Secondary outcomes were postoperative complications and readmissions. RESULTS: Average age, gender ratio, and comorbidities were similar in all three cohorts. Only two patients in the study experienced complications and these were without secondary adverse consequences. Mean costs were substantially reduced when UKAs were performed in an ASC ($9,025) compared to a community hospital on either an outpatient ($12,032) or inpatient basis ($14,542). CONCLUSION: UKA can be safely performed in the outpatient setting, in appropriately selected patients, at substantial cost savings, particularly when performed in an ASC.

Image-Free Robotic-Assisted Total Knee Arthroplasty Results in Quicker Recovery but Equivalent One-Year Outcomes Compared to Conventional Total Knee Arthroplasty.

BACKGROUND: Few studies have addressed whether robotic-assisted total knee arthroplasty (RA-TKA) significantly impacts functional outcomes. This study was conducted to determine whether image-free RA-TKA improves function compared to conventional total knee arthroplasty (C-TKA), performed without the utilization of robotics or navigation, using the Minimal Clinically Important Difference (MCID) and Patient Acceptable Symptom State (PASS) as measures of meaningful clinical improvement. METHODS: A multicenter propensity score-matched retrospective study was conducted of RA-TKA using an image-free robotic system and C-TKA cases at an average follow-up of 14 months (range, 12 months to 20 months). Consecutive patients who underwent primary unilateral TKA and had a preoperative and postoperative Knee Injury and Osteoarthritis Outcome Score-Joint Replacement (KOOS-JR) were included. The primary outcomes were the MCID and PASS for KOOS-JR. 254 RA-TKA and 762 C-TKA patients were included, with no significant differences in sex, age, body mass index, or comorbidities. RESULTS: Preoperative KOOS-JR scores were similar in the RA-TKA and C-TKA cohorts. Significantly greater improvement in KOOS-JR scores were achieved at 4 to 6 weeks postoperatively with RA-TKA compared to C-TKA. While the mean 1-year postoperative KOOS-JR was significantly higher in the RA-TKA cohort, no significant differences were found in the Delta KOOS-JR scores between the cohorts, when comparing preoperative and 1-year postoperative. No significant differences existed in the rates of MCID or PASS being achieved. CONCLUSION: Image-free RA-TKA reduces pain and improves early functional recovery compared to C-TKA at 4 to 6 weeks, but functional outcomes at 1 year are equivalent based on the MCID and PASS for KOOS-JR.

Moving beyond radiographic alignment: applying the Wald Principles in the adoption of robotic total knee arthroplasty.

The use of robotics in total knee arthroplasty (TKA) is growing at an exponential rate. Despite the improved accuracy and reproducibility of robotic-assisted TKA, consistent clinical benefits have yet to be determined, with most studies showing comparable functional outcomes and survivorship between robotic and conventional techniques. Given the success and durability of conventional TKA, measurable improvements in these outcomes with robotic assistance may be difficult to prove. Efforts to optimize component alignment within two degrees of neutral may be an attainable but misguided goal. Applying the "Wald Principles" of rationalization, it is possible that robotic technology may still prove beneficial, even when equivalent clinical outcomes as conventional methods, if we look beyond the obvious surrogate measures of success. Robotic systems may help to reduce inventory, streamline surgical trays, enhance workflows and surgical efficiency, optimize soft tissue balancing, improve surgeon ergonomics, and integrate artificial intelligence and machine learning algorithms into a broader digital ecosystem. This article explores these less obvious alternative benefits of robotic surgery in the field of TKA.

Manipulation Under Anesthesia is Safe After Cementless Total Knee Arthroplasty: A Multicenter Study.

BACKGROUND: Cementless total knee arthroplasty (TKA) is thought to facilitate durable, biological fixation between the bone and implant. However, the 4-12 weeks required for osseointegration coincides with the optimal timeframe to perform a manipulation under anesthesia (MUA) if a patient develops postoperative stiffness. This study aims to determine the impact of early MUA on cementless fixation by comparing functional outcomes and survivorship of cementless and cemented TKAs. METHODS: A consecutive series of patients who underwent MUA for postoperative stiffness within 90 days of primary, unilateral TKA at 2 academic institutions between 2014 and 2018 were identified. Cases involving extensive hardware removal were excluded. Cementless TKAs undergoing MUA (n = 100) were propensity matched 1:1 to cemented TKAs undergoing MUA (n = 100) using age, gender, body mass index, and year of surgery. Both groups had comparable baseline Knee Injury and Osteoarthritis Outcome Scores (KOOS), Short Form (SF)-12 Physical, and SF-12 Mental scores. MUA-related complications as well as postoperative KOOS and SF-12 scores were compared. RESULTS: MUA-related complications were equivalently low in both groups (P = .324), with only 1 patella component dissociation in the cementless group. No tibial or femoral components acutely loosened in the perioperative period. Postoperative KOOS (P = .101) and SF-12 Mental scores (P = .380) were similar between groups. Six-year survivorship free from any revision after MUA was 98.0% in both groups (P = 1.000). CONCLUSION: Early postoperative MUA after cementless TKA was not associated with increased MUA-related complications or worse patient-reported outcomes compared to cemented TKA. Short-term survivorship was also comparable, suggesting high durability of the bone-implant interface.

Surgeons Experience More Physiologic Stress and Strain During Revision Than Primary Total Joint Arthroplasty.

BACKGROUND: Revision total knee arthroplasty (rTKA) and total hip arthroplasty (rTHA) procedures are more complex than primary TKA and THA, but their physiologic burden to the surgeon has not been quantified. While rTKA and rTHA have longer operative times, it is unknown whether differences exist in stress and strain compared to primary TKA and primary THA. The study was conducted to elicit whether differences exist in surgeon physiological response while performing rTKA and rTKA compared to primary TKA and primary THA. METHODS: We evaluated a prospective cohort study of 70 consecutive cases (23 primary TKAs, 12 primary THAs, 16 rTKAs, and 19 rTHAs). Two high-volume fellowship-trained arthroplasty surgeons wore a smart vest that recorded cardiorespiratory data while performing primary THA, primary TKA, rTHA, and rTKA. Heart rate (beats/minute), stress index (correlates with sympathetic activation), respiratory rate (respirations/minute), minute ventilation (L/min), and energy expenditure (Calories) were collected for every case, along with patient body mass index (kilograms/meter2) and working operative time (minutes). T-tests were used to assess for differences between the two groups. RESULTS: Compared to primary TKA, performing rTKAs had a significantly higher surgeon stress index (17 versus 15; P = .035), heart rate (104 versus 99; P = .007), energy expenditure per case (409 versus 297; P = .002), and a significantly lower heart rate variability (11 versus 12; P = .006). Compared to primary THA, performing rTHA had a significantly higher energy expenditure per case (431 versus 307; P = .007) and trended towards having a higher surgeon stress index (16 versus 14; P = .272) and a lower heart rate variability (11 versus 12; P = .185), although it did not reach statistical significance. CONCLUSION: Surgeons experience higher physiological stress and strain when performing rTKA and rTHA compared to primary TKA and primary THA. This study provides objective data on what many surgeons feel and should promote further research on the specific stress and strain felt by surgeons who perform revision arthroplasty procedures.