The outcome of revision total hip arthroplasty for instability.

Aims: Instability is a common indication for revision total hip arthroplasty (THA). However, even after the initial revision, some patients continue to have recurrent dislocation. The aim of this study was to assess the risk for recurrent dislocation after revision THA for instability. Methods: Between 2009 and 2019, 163 patients underwent revision THA for instability at Stanford University Medical Center. Of these, 33 (20.2%) required re-revision due to recurrent dislocation. Cox proportional hazard models, with death and re-revision surgery for periprosthetic infection as competing events, were used to analyze the risk factors, including the size and alignment of the components. Paired t-tests or Wilcoxon signed-rank tests were used to assess the outcome using the Veterans RAND 12 (VR-12) physical and VR-12 mental scores, the Harris Hip Score (HHS) pain and function, and the Hip disability and Osteoarthritis Outcome score for Joint Replacement (HOOS, JR). Results: The median follow-up was 3.1 years (interquartile range 2.0 to 5.1). The one-year cumulative incidence of recurrent dislocation after revision was 8.7%, which increased to 18.8% at five years and 31.9% at ten years postoperatively. In multivariable analysis, a high American Society of Anesthesiologists (ASA) grade (hazard ratio (HR) 2.72 (95% confidence interval (CI) 1.13 to 6.60)), BMI between 25 and 30 kg/m2 (HR 4.31 (95% CI 1.52 to 12.27)), the use of specialized liners (HR 5.39 (95% CI 1.97 to 14.79) to 10.55 (95% CI 2.27 to 49.15)), lumbopelvic stiffness (HR 6.03 (95% CI 1.80 to 20.23)), and postoperative abductor weakness (HR 7.48 (95% CI 2.34 to 23.91)) were significant risk factors for recurrent dislocation. Increasing the size of the acetabular component by > 1 mm significantly decreased the risk of dislocation (HR 0.89 (95% CI 0.82 to 0.96)). The VR-12 physical and HHS (pain and function) scores improved significantly at mid term. Conclusion: Patients requiring revision THA for instability are at risk of recurrent dislocation. Higher ASA grades, being overweight, a previous lumbopelvic fusion, the use of specialized liners, and postoperative abductor weakness are significant risk factors.

Detecting contamination events during robotic total joint arthroplasty.

BACKGROUND: Robot-assisted total joint arthroplasty (robotic-TJA) has become more widespread over the last 20 years due to higher patient satisfaction and reduced complications. However, robotic TJA may have longer operative times and increased operating room traffic, which are known risk factors for contamination events. Contamination of surgical instruments may be contact- or airborne-related with documented scalpel blade contamination rates up to 9%. The robot arm is a novel instrument that comes in and out of the surgical field, so our objective was to assess whether the robot arm is a source of contamination when used in robotic TJA compared to other surgical instruments. METHODS: This was a prospective, single-institution, single-surgeon pilot study involving 103 robotic TJAs. The robot arm was swabbed prior to incision and after closure. Pre- and postoperative control swabs were also collected from the suction tip and scalpel blade. Swabs were incubated for 24 hours on tryptic soy agar followed by inspection for growth of any contaminating bacteria. RESULTS: A contamination event was detected in 10 cases (10%). The scalpel blade was the most common site of contamination (8%) followed by the robot arm (2%) and suction tip (0%). DISCUSSION: Robotic TJA is contaminated with bacteria at a rate around 10%. Although the robot arm is an additional source of potential contamination, the robot arm accrues bacterial contamination infrequently compared to the scalpel blade. CONCLUSION: Contamination of the robot arm during robotic TJA is minimal when compared to contamination of the scalpel blade.

An Inclusive Analysis of Racial and Ethnic Disparities in Orthopedic Surgery Outcomes.

BACKGROUND: Despite increasing attention, disparities in outcomes for Black and Hispanic patients undergoing orthopedic surgery are widening. In other racial-ethnic minority groups, outcomes often go unreported. We sought to quantify disparities in surgical outcomes among Asian, American Indian or Alaskan Native, and Native Hawaiian or Pacific Islander patients across multiple orthopedic subspecialties. MATERIALS AND METHODS: The National Surgical Quality Improvement Program was queried to identify all surgical procedures performed by an orthopedic surgeon from 2014 to 2020. Multivariable logistic regression models were used to investigate the impact of race and ethnicity on 30-day medical complications, readmission, reoperation, and mortality, while adjusting for orthopedic subspecialty and patient characteristics. RESULTS: Across 1,512,480 orthopedic procedures, all patients who were not White were less likely to have arthroplasty-related procedures (P<.001), and Hispanic, Asian, and American Indian or Alaskan Native patients were more likely to have trauma-related procedures (P<.001). American Indian or Alaskan Native (adjusted odds ratio [AOR], 1.005; 95% CI, 1.001-1.009; P=.011) and Native Hawaiian or Pacific Islander (AOR, 1.009; 95% CI, 1.005-1.014; P<.001) patients had higher odds of major medical complications compared with White patients. American Indian or Alaskan Native patients had higher risk of reoperation (AOR, 1.005; 95% CI, 1.002-1.008; P=.002) and Native Hawaiian or Pacific Islander patients had higher odds of mortality (AOR, 1.003; 95% CI, 1.000-1.005; P=.019) compared with White patients. CONCLUSION: Disparities regarding surgical outcome and utilization rates persist across orthopedic surgery. American Indian or Alaskan Native and Native Hawaiian or Pacific Islander patients, who are under-represented in research, have lower rates of arthroplasty but higher odds of medical complication, reoperation, and mortality. This study highlights the importance of including these patients in orthopedic research to affect policy-related discussions. [Orthopedics. 2024;47(3):e131-e138.].

The PJI-TNM classification for periprosthetic joint infections.

Aims: This study aimed to evaluate the clinical application of the PJI-TNM classification for periprosthetic joint infection (PJI) by determining intraobserver and interobserver reliability. To facilitate its use in clinical practice, an educational app was subsequently developed and evaluated. Methods: A total of ten orthopaedic surgeons classified 20 cases of PJI based on the PJI-TNM classification. Subsequently, the classification was re-evaluated using the PJI-TNM app. Classification accuracy was calculated separately for each subcategory (reinfection, tissue and implant condition, non-human cells, and morbidity of the patient). Fleiss' kappa and Cohen's kappa were calculated for interobserver and intraobserver reliability, respectively. Results: Overall, interobserver and intraobserver agreements were substantial across the 20 classified cases. Analyses for the variable 'reinfection' revealed an almost perfect interobserver and intraobserver agreement with a classification accuracy of 94.8%. The category 'tissue and implant conditions' showed moderate interobserver and substantial intraobserver reliability, while the classification accuracy was 70.8%. For 'non-human cells,' accuracy was 81.0% and interobserver agreement was moderate with an almost perfect intraobserver reliability. The classification accuracy of the variable 'morbidity of the patient' reached 73.5% with a moderate interobserver agreement, whereas the intraobserver agreement was substantial. The application of the app yielded comparable results across all subgroups. Conclusion: The PJI-TNM classification system captures the heterogeneity of PJI and can be applied with substantial inter- and intraobserver reliability. The PJI-TNM educational app aims to facilitate application in clinical practice. A major limitation was the correct assessment of the implant situation. To eliminate this, a re-evaluation according to intraoperative findings is strongly recommended.

Arthroplasty for femoral neck fractures is at risk for under restoration of lateral femoral offset.

PURPOSE: The aim of the study was to determine the restoration of hip biomechanics through lateral offset, leg length, and acetabular component position when comparing non-arthroplasty surgeons (NAS) to elective arthroplasty surgeons (EAS). METHODS: 131 patients, with a femoral neck fracture treated with a THA by 7 EAS and 20 NAS, were retrospectively reviewed. 2 blinded observers measured leg-length discrepancy, femoral offset, and acetabular component position. Multivariate logistic regression models examined the association between the surgeon groups and restoration of lateral femoral, acetabular offset, leg length discrepancy, acetabular anteversion, acetabular position, and component size, while adjusting for surgical approach and spinal pathology. RESULTS: NAS under-restored 4.8 mm of lateral femoral offset (43.9 ± 8.7 mm) after THA when compared to the uninjured side (48.7 ± 7.1 mm, p = 0.044). NAS were at risk for under-restoring lateral femoral offset when compared to EAS (p = 0.040). There was no association between lateral acetabular offset, leg length, acetabular position, or component size and surgeon type. CONCLUSIONS: Lateral femoral offset is at risk for under-restoration after THA for femoral neck fractures, when performed by surgeons that do not regularly perform elective THA. This indicates that lateral femoral offset is an under-appreciated contributor to hip instability when performing THA for a femoral neck fracture. Lateral femoral offset deserves as much attention and awareness as acetabular component position since a secondary analysis of our data reveal that preoperative templating and intraoperative imaging did not prevent under-restoration.

Practice Changes Induced by a Traveling Fellowship.

The John N. Insall Knee Society Traveling Fellowship selects four international arthroplasty or sports fellowship-trained orthopaedic surgeons to spend 1 month traveling to various Knee Society members' joint replacement and knee surgery centers in North America. The fellowship aims to foster research and education and shares ideas among fellows and Knee Society members. The role of such traveling fellowships on surgeon preferences has yet to be investigated. A 59-question survey encompassing patient selection, preoperative planning, intraoperative techniques, and postoperative protocols was completed by the four 2018 Insall Traveling Fellows before and immediately after the completion of traveling fellowship to assess anticipated practice changes (e.g., initial excitement) related to their participation in a traveling fellowship. The same survey was completed 4 years after the completion of the traveling fellowship to assess the implementation of the anticipated practice changes. Survey questions were divided into two groups based on levels of evidence in the literature. Immediately after fellowship, there was a median of 6.5 (range: 3-12) anticipated changes in consensus topics and a median of 14.5 (range: 5-17) anticipated changes in controversial topics. There was no statistical difference in the excitement to change consensus or controversial topics (p = 0.921). Four years after completing a traveling fellowship, a median of 2.5 (range: 0-3) consensus topics and 4 (range: 2-6) controversial topics were implemented. There was no statistical difference in the implementation of consensus or controversial topics (p = 0.709). There was a statistically significant decline in the implementation of changes in consensus and controversial preferences compared with the initial level of excitement (p = 0.038 and 0.031, respectively). After the John N. Insall Knee Society Traveling Fellowship, there is excitement for practice change in consensus and controversial topics related to total knee arthroplasty. However, few practice changes that had initial excitement were implemented after 4-year follow-up. Ultimately, the effects of time, practice inertia, and institutional friction overcome most of the anticipated changes induced by a traveling fellowship.

Host and microbial characteristics associated with recurrent prosthetic joint infections.

Approximately 20% of patients after resection arthroplasty and antibiotic spacer placement for prosthetic joint infection develop repeat infections, requiring an additional antibiotic spacer before definitive reimplantation. The host and bacterial characteristics associated with the development of recurrent infection is poorly understood. A case-control study was conducted for 106 patients with intention to treat by two-stage revision arthroplasty for prosthetic joint infection at a single institution between 2009 and 2020. Infection was defined according to the 2018 Musculoskeletal Infection Society criteria. Thirty-nine cases ("recurrent-periprosthetic joint infection [PJI]") received at least two antibiotic spacers before clinical resolution of their infection, and 67 controls ("single-PJI") received a single antibiotic cement spacer before infection-free prosthesis reimplantation. Patient demographics, McPherson host grade, and culture results including antibiotic susceptibilities were compared. Fifty-two (78%) single-PJI and 32 (82%) recurrent-PJI patients had positive intraoperative cultures at the time of their initial spacer procedure. The odds of polymicrobial infections were 11-fold higher among recurrent-PJI patients, and the odds of significant systemic compromise (McPherson host-grade C) were more than double. Recurrent-PJI patients were significantly more likely to harbor Staphylococcus aureus. We found no differences between cases and controls in pathogen resistance to the six most tested antibiotics. Among recurrent-PJI patients, erythromycin-resistant infections were more prevalent at the final than initial spacer, despite no erythromycin exposure. Our findings suggest that McPherson host grade, polymicrobial infection, and S. aureus infection are key indicators of secondary or persistent joint infection following resection arthroplasty and antibiotic spacer placement, while bacterial resistance does not predict infection-related arthroplasty failure.

Is There Variation in Time to and Type of Treatment for Hip Osteoarthritis Based on Insurance?

BACKGROUND: Disparities in care access based on insurance exist for total hip arthroplasty (THA), but it is unclear if these lead to longer times to surgery. We evaluated whether rates of THA versus nonoperative interventions (NOI) and time to THA from initial hip osteoarthritis (OA) diagnosis vary by insurance type. METHODS: Using a national claims database, patients who had hip OA undergoing THA or NOI from 2011 to 2019 were identified and divided by insurance type: Medicaid-managed care; Medicare Advantage; and commercial insurance. The primary outcome was THA incidence within 3 years after hip OA diagnosis. Multivariable logistic regression models were created to assess the association between THA and insurance type, adjusting for age, sex, region, and comorbidities. RESULTS: Medicaid patients had lower rates of THA within 3 years of initial diagnosis (7.4 versus 10.9 or 12.0%, respectively; P < .0001) and longer times to surgery (297 versus 215 or 261 days, respectively; P < .0001) compared to Medicare Advantage and commercially-insured patients. In multivariable analyses, Medicaid patients were also less likely to receive THA (odds ratio (OR) = 0.62 [95% confidence intervals (CI): 0.60 to 0.64] versus Medicare Advantage, OR = 0.63 [95% CI: 0.61 to 0.64] versus commercial) or NOI (OR = 0.92 [95% CI: 0.91 to 0.94] versus Medicare Advantage, OR = 0.81 [95% CI: 0.79 to 0.82] versus commercial). CONCLUSIONS: Medicaid patients experienced lower rates of and longer times to THA than Medicare Advantage or commercially-insured patients. Further investigation into causes of these disparities, such as costs or access barriers, is necessary to ensure equitable care.

Costs and Outcomes of Total Joint Arthroplasty in Medicare Beneficiaries Are Not Meaningfully Associated with Industry Payments.

BACKGROUND: Prior studies have demonstrated that industry payments affect physician prescribing patterns, but their effect on orthopaedic surgical costs is unknown. This study examines the relationship between industry payments and the total costs of primary total joint arthroplasty, as well as operating room cost, length of stay, 30-day mortality, and 30-day readmission. METHODS: Open Payments data were matched across a 20% sample of Medicare-insured patients undergoing primary elective total hip arthroplasty (THA) (n = 130,872) performed by 7,539 surgeons or primary elective total knee arthroplasty (TKA) (n = 230,856) performed by 8,977 surgeons from 2013 to 2015. Patient, hospital, and surgeon-specific factors were gathered. Total and operating room costs, length of stay, mortality, and readmissions were recorded. Multivariable linear and logistic regression models were used to identify the risk-adjusted relationships between industry payments and the primary and secondary outcomes. RESULTS: In this study, 96.7% of THA surgeons and 97.4% of TKA surgeons received industry payments. After multivariable risk adjustment, for each $1,000 increase in industry payments, the total costs of THA increased by $0.50 (0.003% of total costs) and the operating room costs of THA increased by $0.20 (0.003% of total costs). Industry payments were not associated with TKA cost. Industry payments were not associated with 30-day mortality after either THA or TKA. Higher industry payments were independently associated with a marginal decrease in the length of stay for patients undergoing THA (0.0045 days per $1,000) or TKA (0.0035 days per $1,000) and a <0.1% increase in the odds of 30-day readmission after THA for every $1,000 in industry payments. The median total THA costs were $300 higher (p < 0.001), whereas the median TKA costs were $150 lower (p < 0.001), for surgeons receiving the highest 5% of industry payments. These surgical procedures were more often performed in large urban areas, in hospitals with a higher number of beds, with a higher wage index, and by more experienced surgeons and were associated with a 0.4 to 1-day shorter length of stay (p < 0.001). CONCLUSIONS: Although most arthroplasty surgeons received industry payments, a minority of surgeons received the majority of payments. Overall, arthroplasty costs and outcomes were not meaningfully impacted by industry relationships. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

An External Acetabular Alignment Guide Decreases Positional Variance.

INTRODUCTION: Certain patient and operative factors limit accurate estimation of acetabular component positioning during total hip arthroplasty (THA). This study aimed to determine whether an intraoperative external alignment guide decreases variance in acetabular component positioning. MATERIALS AND METHODS: Adult patients who underwent primary THA from 2014-2018 were reviewed. Exclusion criteria were navigation, robot-assisted surgery, and inflammatory, post-traumatic, or avascular arthritis. One surgeon used an external guide while the second surgeon resected osteophytes and utilized available anatomical landmarks for positioning. Anteversion and inclination, variance, "safe zone" positioning, operative time, and hip instability were assessed. Multivariable regression models were used to examine effects on primary and secondary outcomes. RESULTS: 409 patients were included, of which 182 underwent component placement with landmarks only. Patients undergoing component placement with landmarks only were younger (p=0.002) and more often smokers (p=0.016). After multivariable risk adjustment, use of the external alignment guide was independently associated with 2.7° higher anteversion (CI: 1.6° to 3.8°) and smaller anteversion variance (-0.3, CI: -0.6 to 0.1) compared to landmarks only. It was independently associated with 3.2° higher inclination (CI: 2.0° to 4.4°), but there was no difference in inclination variance (-0.1, CI: -0.3 to 0.2). The external alignment guide was independently associated with a 14-minute shorter operative time (CI: 9.6 to 18.7) and smaller operative time variance (-0.9, CI: -1.2 to 0.6). DISCUSSION: Use of anatomical landmarks alone was associated with increased likelihood of safe zone positioning but lower precision and longer operative time. While this study was limited by lack of randomization and its retrospective nature, an acetabular positioner may be preferable to palpable or visible anatomy alone for acetabular component placement.

Is Operative Time Associated With Obesity-related Outcomes in TKA?

BACKGROUND: Obesity-based cutoffs in TKA are premised on higher rates of postoperative complications. However, operative time may be associated with postoperative complications, leading to an unnecessary restriction of TKA in patients with obesity. If operative time is associated with these obesity-related outcomes, it should be accounted for in order to ensure all measurable factors associated with negative outcomes are examined for patients with obesity after TKA. QUESTIONS/PURPOSES: We asked: (1) Is operative time, controlling for BMI class, associated with readmission, reoperation, and postoperative major and minor complications? (2) Is operative time associated with a difference in the direction or strength of obesity-related adverse outcomes? METHODS: In this comparative study, we extracted all records on elective, unilateral TKA between January 2014 and December 2020 in the American College of Surgeons National Surgical Quality Improvement Program database, resulting in an initial sample of 394,381 TKAs. Patients with emergency procedures (0.1% [270]) and simultaneous bilateral TKAs (2% [8736]), missing or null data (1% [4834]), and those with operative times less than 25 minutes (0.1% [548]) were excluded, leaving 96% (379,993) of our original sample size. The National Surgical Quality Improvement Program database was selected because of its inclusion of operative time, which is not found in any other national database. BMI was subdivided into underweight (BMI < 18.5 kg/m2, < 1% [719]), normal weight (BMI 18.5 to 24.9 kg/m2, 9% [34,513]), overweight (BMI 25.0 to 29.9 kg/m2, 27% [101,538]), Class I obesity (BMI 30.0 to 34.9 kg/m2, 29% [111,712]), Class II obesity (BMI 35.0 to 39.9 kg/m2, 20% [76,605]), and Class III obesity (BMI ≥ 40.0 kg/m2, 14% [54,906]). The mean operative time was 91 ± 36 minutes, 61% of patients were women (233,062 of 379,993), and the mean age was 67 ± 9 years. Patients with obesity tended to be younger and more likely to have preoperative comorbidities and longer operative times than patients with normal weight. Multivariable logistic regression models examined the main effects of operative time with respect to 30-day readmission, reoperation, and major and minor medical complications, while adjusting for BMI class and other covariates including age, sex, race, smoking status, and number of preoperative comorbidities. We then evaluated the potential interaction effect of BMI class and operative time. This interaction term helps determine whether the association of BMI with postoperative outcomes changes based on the duration of the surgery, and vice versa. If the interaction term is statistically significant, it implies the association of BMI with adverse postoperative outcomes is inconsistent across all patients. Instead, it varies with the operative time. Adjusted odds ratios and 95% confidence intervals were calculated, and interaction effects were plotted. RESULTS: After controlling for obesity, longer procedure duration was independently associated with higher odds of all outcomes (30-minute estimates; adjusted ORs are per minute), including readmission (9% per half-hour of surgical duration; adjusted OR 1.003 [95% CI 1.003 to 1.004]; p < 0.001), reoperation (15% per half-hour of surgical duration; adjusted OR 1.005 [95% CI 1.004 to 1.005]; p < 0.001), postoperative major complications (9% per half-hour of surgical duration; adjusted OR 1.003 [95% CI 1.003 to 1.004]; p < 0.001), and postoperative minor complications (18% per half-hour of surgical duration; adjusted OR 1.006 [95% CI 1.006 to 1.007]; p < 0.001). The interaction effect indicates that patients with obesity had lower odds of reoperation than patients with normal weight when operative times were shorter, but higher odds of reoperation with a longer operative duration. CONCLUSION: We found that operative time, a proxy for surgical complexity, had a moderate, differential association with obesity over a 30-minute period. Perioperative modification of surgical complexity such as surgical techniques, training, and team dynamics may make safe TKA possible for certain patients who might have otherwise been denied surgery. Decisions to refuse TKA to patients with obesity should be based on a holistic assessment of a patient's operative complexity, rather than strictly assessing a patient's weight or their ability to lose weight. Future studies should assess patient-specific characteristics that are associated with operative time, which can further push the development of techniques and strategies that reduce surgical complexity and improve TKA outcomes. LEVEL OF EVIDENCE: Level III, therapeutic study.

Preoperative Versus Perioperative Risk Factors for Delayed Pain and Opioid Cessation After Total Joint Arthroplasty: A Prospective Cohort Study.

INTRODUCTION: The evolution of pre- versus postoperative risk factors remains unknown in the development of persistent postoperative pain and opioid use. We identified preoperative versus comprehensive perioperative models of delayed pain and opioid cessation after total joint arthroplasty including time-varying postoperative changes in emotional distress. We hypothesized that time-varying longitudinal measures of postoperative psychological distress, as well as pre- and postoperative use of opioids would be the most significant risk factors for both outcomes. METHODS: A prospective cohort of 188 patients undergoing total hip or knee arthroplasty at Stanford Hospital completed baseline pain, opioid use, and emotional distress assessments. After surgery, a modified Brief Pain Inventory was assessed daily for 3 months, weekly thereafter up to 6 months, and monthly thereafter up to 1 year. Emotional distress and pain catastrophizing were assessed weekly to 6 months, then monthly thereafter. Stepwise multivariate time-varying Cox regression modeled preoperative variables alone, followed by all perioperative variables (before and after surgery) with time to postoperative opioid and pain cessation. RESULTS: The median time to opioid and pain cessation was 54 and 152 days, respectively. Preoperative total daily oral morphine equivalent use (hazard ratio-HR 0.97; 95% confidence interval-CI 0.96-0.98) was significantly associated with delayed postoperative opioid cessation in the perioperative model. In contrast, time-varying postoperative factors: elevated PROMIS (Patient-Reported Outcomes Measurement Information System) depression scores (HR 0.92; 95% CI 0.87-0.98), and higher Pain Catastrophizing Scale scores (HR 0.85; 95% CI 0.75-0.97) were independently associated with delayed postoperative pain resolution in the perioperative model. CONCLUSIONS: These findings highlight preoperative opioid use as a key determinant of delayed postoperative opioid cessation, while postoperative elevations in depressive symptoms and pain catastrophizing are associated with persistent pain after total joint arthroplasty providing the rationale for continued risk stratification before and after surgery to identify patients at highest risk for these distinct outcomes. Interventions targeting these perioperative risk factors may prevent prolonged postoperative pain and opioid use.

Lack of alignment between orthopaedic surgeon priorities and patient expectations in total joint arthroplasty.

BACKGROUND: Healthcare systems are shifting toward "patient-centered" care often without assessing the values important to patients. Analogously, the interests of the patient may be disparate with physician interests, as pay-for-performance models become common. The purpose of the study was to determine which medical preferences are essential for patients during their surgical care. METHODS: This prospective, observational study surveyed 102 patients who had undergone a primary knee replacement and/or hip replacement surgery about hypothetical scenarios regarding their surgical experience. Data analysis included categorical variables presented as a number and percent, while continuous variables presented as mean and standard deviation. Statistical analysis for anticoagulation data included the Pearson chi-square test and one-way ANOVA test. RESULTS: A large majority, 73 patients (72%), would not pay to have a four-centimeter or smaller incision. The remaining 29 patients (28%) would prefer to have a four-centimeter or smaller incision and would pay a mean of $1,328 ± 1,629 for that day. A significant number of patients preferred not to use anticoagulation (p = 0.019); however, the value attributed to avoiding a specific method of anticoagulation was found not to be significant (p = 0.507). CONCLUSIONS: The study determined the metrics prioritized by hospitals and surgeons are not important to the majority of patients when they evaluate their own care. These disconnects in the entitlements patients expect and receive can be solved by including patients in discussions with physicians and hospital systems.

Selecting a high-dose antibiotic-laden cement knee spacer.

Prosthetic joint infection [PJI] after total knee arthroplasty (TKA) remains a common and challenging problem for joint replacement surgeons and patients. Once the diagnosis of PJI has been made, patient goals and characteristics as well as the infection timeline dictate treatment. Most commonly, this involves a two-stage procedure with the removal of all implants, debridement, and placement of a static or dynamic antibiotic spacer. Static spacers are commonly indicated for older, less healthy patients that would benefit from soft tissue rest after initial debridement. Mobile spacers are typically used in younger, healthier patients to improve quality of life and reduce soft-tissue contractures during antibiotic spacer treatment. Spacers are highly customizable with regard to antibiotic choice, cement variety, and spacer design, each with reported advantages, drawbacks, and indications that will be covered in this article. While no spacer is superior to any other, the modern arthroplasty surgeon must be familiar with the available modalities to optimize treatment for each patient. Here we propose a treatment algorithm to assist surgeons in deciding on treatment for PJI after TKA.

AOA Critical Issues Symposium: Shaping the Impact of Artificial Intelligence within Orthopaedic Surgery.

ABSTRACT: Artificial intelligence (AI) is a broad term that is widely used but inconsistently understood. It refers to the ability of any machine to exhibit human-like intelligence by making decisions, solving problems, or learning from experience. With its ability to rapidly process large amounts of information, AI has already transformed many industries such as entertainment, transportation, and communications through consumer-facing products and business-to-business applications. Given its potential, AI is also anticipated to impact the practice of medicine and the delivery of health care. Interest in AI-based techniques has grown rapidly within the orthopaedic community, resulting in an increasing number of publications on this topic. Topics of interest have ranged from the use of AI for imaging interpretation to AI-based techniques for predicting postoperative outcomes.The highly technical and data-driven nature of orthopaedic surgery creates the potential for AI, and its subdisciplines machine learning (ML) and deep learning (DL), to fundamentally transform our understanding of musculoskeletal care. However, AI-based techniques are not well known to most orthopaedic surgeons, nor are they taught with the same level of insight and critical thinking as traditional statistical methodology. With a clear understanding of the science behind AI-based techniques, orthopaedic surgeons will be able to identify the potential pitfalls of the application of AI to musculoskeletal health. Additionally, with increased understanding of AI, surgeons and their patients may have more trust in the results of AI-based analytics, thereby expanding the potential use of AI in clinical care and amplifying the impact it could have in improving quality and value. The purpose of this American Orthopaedic Association (AOA) symposium was to facilitate understanding and development of AI and AI-based techniques within orthopaedic surgery by defining common terminology related to AI, demonstrating the existing clinical utility of AI, and presenting future applications of AI in surgical care.

Does Operative Time Modify Obesity-related Outcomes in THA?

BACKGROUND: Most orthopaedic surgeons refuse to perform arthroplasty on patients with morbid obesity, citing the higher rate of postoperative complications. However, that recommendation does not account for the relationship of operative time (which is often longer in patients with obesity) to obesity-related arthroplasty outcomes, such as readmission, reoperation, and postoperative complications. If operative time is associated with these obesity-related outcomes, it should be accounted for and addressed to properly assess the risk of patients with obesity undergoing THA. QUESTIONS/PURPOSES: We therefore asked: (1) Is the increased risk seen in overweight and obese patients, compared with patients in a normal BMI class, associated with increased operative time? (2) Is increased operative time independent of BMI class a risk factor for readmission, reoperation, and postoperative medical complications? (3) Does operative time modify the direction or strength of obesity-related adverse outcomes? METHODS: This retrospective, comparative study examined 247,108 patients who underwent THA between January 2014 and December 2020 in the National Surgical Quality Improvement Project (NSQIP). Of those, emergency cases (1% [2404]), bilateral procedures (1% [1605]), missing and/or null data (1% [3280]), extreme BMI and operative time outliers (1% [2032]), and patients with comorbidities that are not typical of an elective procedure, such as disseminated cancer, open wounds, sepsis, and ventilator dependence (1% [2726]), were excluded, leaving 95% (235,061) of elective, unilateral THA cases for analysis. The NSQIP was selected due to its inclusion of operative time, which is not found in any other national database. BMI was subdivided into underweight, normal weight, overweight, Class I obesity, Class II obesity, and Class III obesity. Of the patients with a normal weight, 69% (30,932 of 44,556) were female and 36% (16,032 of 44,556) had at least one comorbidity, with a mean operative time of 86 ± 32 minutes and a mean age of 68 ± 12 years. Patients with obesity tend to be younger, male, more likely to have preoperative comorbidities, with longer operative times. Multivariable logistic regression models examined the effects of obesity on 30-day readmission, reoperation, and medical complications, while adjusting for age, sex, race, smoking status, and number of preoperative comorbidities. After we repeated this analysis after adjusting for operative time, an interaction model was conducted to test whether operative time changes the direction or strength of the association of BMI class and adverse outcomes. Adjusted odds ratios (AOR) and 95% confidence intervals (CIs) were calculated, and the interaction effects were plotted. RESULTS: A comparison of patients with Class III obesity to patients with normal weight showed that the odds of readmission went from 45% (AOR 1.45 [95% CI 1.32 to 1.59]; p < 0.001) to 27% after adjusting for operative time (AOR 1.27 [95% CI 1.01 to 1.62]; p = 0.04), the odds of reoperation went from 93% (AOR 1.93 [95% CI 1.72 to 2.17]; p < 0.001) to 81% after adjusting for operative time (AOR 1.81 [95% CI 1.61 to 2.04]; p < 0.001), and the odds of a postoperative complication went from 96% (AOR 1.96 [95% CI 1.58 to 2.43]; p < 0.001) to 84% after adjusting for operative time (AOR 1.84 [95% CI 1.48 to 2.28]; p < 0.001). Each 15-minute increase in operative time was associated with a 7% increase in the odds of a readmission (AOR 1.07 [95% CI 1.06 to 1.08]; p < 0.001), a 10% increase in the odds of a reoperation (AOR 1.10 [95% CI 1.09 to 1.12]; p < 0.001), and 10% increase in the odds of a postoperative complication (AOR 1.10 [95% CI 1.08 to 1.13]; p < 0.001). There was a positive interaction effect of operative time and BMI for readmission and reoperation, which suggests that longer operations accentuate the risk that patients with obesity have for readmission and reoperation. CONCLUSION: Operative time is likely a proxy for surgical complexity and contributes modestly to the adverse outcomes previously attributed to obesity alone. Hence, focusing on modulating the accentuated risk associated with lengthened operative times rather than obesity is imperative to increasing the accessibility and safety of THA. Surgeons may do this with specific surgical techniques, training, and practice. Future studies looking at THA outcomes related to obesity should consider the association with operative time to focus on independent associations with obesity to facilitate more equitable access. LEVEL OF EVIDENCE: Level III, therapeutic study.

Comparing Unicompartmental Knee Arthroplasty and High Tibial Osteotomy for Isolated Medial Compartment Knee Osteoarthritis.

¼: Both unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) allow for compartment-specific intervention on an arthritic knee joint that preserves bone stock and native soft tissue compared to a total knee arthroplasty (TKA). Both operations give a more natural feeling with native proprioception compared with a TKA. ¼: HTO is better suited in patients who are younger (<55 years-of-age), have a body mass index (BMI) <30 kg/m2, high activity requirements, mechanical malalignment, asymmetric varus, isolated anterior cruciate ligament insufficiency, need for multiplanar correction, and a preference for joint preserving interventions. Recent data suggest that age (>55 years-of-age) should not solely contraindicate a HTO. ¼: UKA may be chosen in patients who are older (>55 years-of-age), low activity requirements, have a BMI <40 kg/m2, severe osteoarthritis with significant joint space narrowing, acceptable coronal alignment, symmetric varus, and patient preference for arthroplasty.

Single, Recurrent, Synchronous, and Metachronous Periprosthetic Joint Infections in Patients With Multiple Hip and Knee Arthroplasties.

BACKGROUND: The rate for periprosthetic joint infection (PJI) exceeds 1% for primary arthroplasties. Over 30% of patients who have a primary arthroplasty require an additional arthroplasty, and the impact of PJI on this population is understudied. Our objective was to assess the prevalence of recurrent, synchronous, and metachronous PJI in patients who had multiple arthroplasties and to identify risk factors for a subsequent PJI. METHODS: We identified 337 patients who had multiple arthroplasties and at least 1 PJI that presented between 2003 and 2021. The mean follow-up after revision arthroplasty was 3 years (range, 0 to 17.2). Patients who had multiple infected prostheses were categorized as synchronous (ie, presenting at the same time as the initial infection) or metachronous (ie, presenting at a different time as the initial infection). The PJI diagnosis was made using the MusculoSkeletal Infection Society (MSIS) criteria. RESULTS: There were 39 (12%) patients who experienced recurrent PJI in the same joint, while 31 (9%) patients developed PJI in another joint. Positive blood cultures were more likely in the second joint PJI (48%) compared to recurrent PJI (23%) or a single PJI (15%, P < .001). Synchronous PJI represented 42% of the second joint PJI cases (n = 13), while metachronous PJI represented 58% (n = 18). Tobacco users had 75% higher odds of metachronous PJI (odds ratio 1.75, 95% confidence interval: 1.1-2.9, P = .041). CONCLUSION: Over 20% of the patients with multiple arthroplasties and a single PJI will develop a subsequent PJI in another arthroplasty with 12% recurring in the initial arthroplasty and nearly 10% ocurring in another arthroplasty. Particular caution should be taken in patients who use tobacco, have bacteremia, or have Staphylococcus aureus isolation at time of their initial PJI. Optimizing the management of this high-risk patient population is necessary to reduce the additional burden of subsequent PJI. LEVEL OF EVIDENCE: Prognostic Level IV.

Assessment of Team Dynamics and Operative Efficiency in Hip and Knee Arthroplasty.

Importance: Surgical team communication is a critical component of operative efficiency. The factors underlying optimal communication, including team turnover, role composition, and mutual familiarity, remain underinvestigated in the operating room. Objective: To assess staff turnover, trainee involvement, and surgeon staff preferences in terms of intraoperative efficiency. Design, Setting, and Participants: Retrospective analysis of staff characteristics and operating times for all total joint arthroplasties was performed at a tertiary academic medical center by 5 surgeons from January 1 to December 31, 2018. Data were analyzed from May 1, 2021, to February 18, 2022. The study included cases with primary total hip arthroplasties (THAs) and primary total knee arthroplasties (TKAs) comprising all primary total joint arthroplasties performed over the 1-year study interval. Exposures: Intraoperative turnover among nonsurgical staff, presence of trainees, and presence of surgeon-preferred staff. Main Outcomes and Measures: Incision time, procedure time, and room time for each surgery. Multivariable regression analyses between operative duration, presence of surgeon-preferred staff, and turnover among nonsurgical personnel were conducted. Results: A total of 641 cases, including 279 THAs (51% female; median age, 64 [IQR, 56.3-71.5] years) and 362 TKAs (66% [238] female; median age, 68 [IQR, 61.1-74.1] years) were considered. Turnover among circulating nurses was associated with a significant increase in operative duration in both THAs and TKAs, with estimated differences of 19.6 minutes (SE, 3.5; P < .001) of room time in THAs and 14.0 minutes (SE, 3.1; P < .001) of room time in TKAs. The presence of a preferred anesthesiologist or surgical technician was associated with significant decreases of 26.5 minutes (SE, 8.8; P = .003) of procedure time and 12.6 minutes (SE, 4.0; P = .002) of room time, respectively, in TKAs. The presence of a surgeon-preferred vendor was associated with a significant increase in operative duration in both THAs (26.3 minutes; SE, 7.3; P < .001) and TKAs (29.6 minutes; SE, 9.6; P = .002). Conclusions and Relevance: This study found that turnover among operative staff is associated with procedural inefficiency. In contrast, the presence of surgeon-preferred staff may facilitate intraoperative efficiency. Administrative or technologic support of perioperative communication and team continuity may help improve operative efficiency.

Complications, Implant Survivorships, and Functional Outcomes of Conversion Total Knee Arthroplasty With Prior Hardware.

BACKGROUND: End-stage knee osteoarthritis with retained periarticular hardware is a frequent scenario. Conversion total knee arthroplasty (TKA) leads to excellent outcomes, but poses unique challenges. The evidence supporting retention versus removal of hardware during TKA is controversial. METHODS: Patients who underwent TKA with prior hardware between January 2009 and December 2019 were identified. A total of 148 patients underwent TKA with prior hardware. The mean follow-up was 60 months (range, 24-223). Univariate and multivariable analyses were used to study correlations among factors and surgical-related complications, prosthesis failures, and functional outcomes. RESULTS: The complication rate was 28 of 148 (18.9%). The use of a quadriceps snips in addition to a medial parapatellar arthrotomy was associated with a higher complication (odds ratio: 20.7, P < .05), implant failures (odds ratio: 13.9, P < .05), and lower the Veterans Rand 12 Mental Score (VR-12 MS) (-14.8, P < .05). Hardware removal versus retention and use of single versus multiple incisions were not associated with complications or prosthesis failures. Removal of all hardware was associated with significantly higher (+7.3, P < .05) VR-12 MS compared to retention of all hardware. CONCLUSIONS: TKA with prior hardware was associated with more complications, implant failures, and lower VR-12 MS when a more constrained construct or quadriceps snip was performed. This probably reflects the level of difficulty of the procedure rather than the surgical approach used. Hardware removal or retention was not associated with complications or implant failures; however, removal rather than retention of all prior hardware is associated with increased general health outcomes. LEVEL OF EVIDENCE: IV, cohort without control.