Total Knee Arthroplasty Cohort Research Articles

Predictive Modeling of Medical and Orthopaedic-Related 90-Day-Readmissions Following Primary Total Knee Arthroplasty

BackgroundAs the demand for total knee arthroplasty (TKA) escalates, 90-day readmissions have emerged as a pressing clinical and economic concern for the current value-based health care system. Consequently, health care providers have focused on estimating the risk levels of readmitted patients; however, it is unknown if specific factors are associated with different types of complications (ie, medical or orthopaedic-related) that lead to readmissions. Therefore, this study aimed to (1) determine the overall, medical-related, and orthopaedic-related 90-day readmission rate and (2) develop a predictive model for risk factors affecting overall, medical-related, and orthopaedic-related 90-day readmissions following TKA. MethodsA prospective cohort of primary unilateral TKAs performed at a large tertiary academic center in the United States from 2016 to 2020 was included (n = 10,521 patients). Unplanned readmissions were reviewed individually to determine their primary cause, either medical or orthopaedic-related. Orthopaedic-related readmissions were specific complications affecting the joint, prosthesis, or surgical wound. Medical readmissions were due to any other cause requiring medical management. Multivariable logistic regression models were used to investigate associations between prespecified risk factors and 90-day readmissions, as well as medical and orthopaedic-related readmissions independently. ResultsOverall, the rate of 90-day readmissions was 6.7% (n = 704). Over 82% of these readmissions were due to medical-related causes (n = 580), with the remaining 18% being orthopaedic-related (n = 124) readmissions. The area under the curve for the 90-day readmission model was 0.68 (95% confidence interval: 0.67 to 0.70). Sex, smoking, length of stay, and discharge disposition were associated with orthopaedic readmission, while age, sex, race, the Charlson Comorbidity Index, insurance, surgery day, opioid overdose risk score, length of stay, and discharge disposition were associated with medical-related 90-day readmissions. ConclusionsMedical-related readmissions after TKA are more prevalent than orthopaedic-related readmissions. Through successfully constructing and validating multiple 90-day readmission predictive models, we highlight the distinct risk profiles for medical and orthopaedic-related readmissions. This emphasizes the necessity for nuanced, patient-specific risk stratification and preventive measures.

Early Clinical and Economic Outcomes for the VELYS Robotic-Assisted Solution Compared with Manual Instrumentation for Total Knee Arthroplasty.

Robotic-assisted total knee arthroplasty (TKA) has been developed to improve functional outcomes after TKA by increasing surgical precision of bone cuts and soft tissue balancing, thereby reducing outliers. The DePuy Synthes VELYS robotic-assisted solution (VRAS) is one of the latest entrants in the robotic TKA market. Currently, there is limited evidence investigating early patient and economic outcomes associated with the use of VRAS. The Premier Healthcare Database was analyzed to identify patients undergoing manual TKA with any implant system compared with a cohort of robotic-assisted TKAs using VRAS between September 1, 2021 and February 28, 2023. The primary outcome was all-cause and knee-related all-setting revisits within 90-day post-TKA. Secondary outcomes included number of inpatient revisits (readmission), operating room time, discharge status, and hospital costs. Baseline covariate differences between the two cohorts were balanced using fine stratification methodology and analyzed using generalized linear models. The cohorts included 866 VRAS and 128,643 manual TKAs that had 90-day follow-up data. The rates of both all-cause and knee-related all-setting follow-up visits (revisits) were significantly lower in the VRAS TKA cohort compared with the manual TKA cohort (13.86 vs. 17.19%; mean difference [MD]: -3.34 [95% confidence interval: -5.65 to -1.03] and 2.66 vs. 4.81%; MD: -2.15 [-3.23 to -1.08], respectively, p-value < 0.01) at 90-day follow-up. The incidence of knee-related inpatient readmission was also significantly lower (53%) for VRAS compared with manual TKA. There was no significant difference between total cost of care at 90-day follow-up between VRAS and manual TKA cases. On average, the operating room time was higher for VRAS compared with manual TKA (138 vs. 134 minutes). In addition, the discharge status and revision rates were similar between the cohorts. The use of VRAS for TKA is associated with lower follow-up visits and knee-related readmission rates in the first 90-day postoperatively. The total hospital cost was similar for both VRAS and manual TKA cohort while not accounting for the purchase of the robot.

Cemented is not superior to cementless total knee arthroplasty for complications: a propensity score matched analysis.

There is continued debate regarding the survivorship and revision rate of cementless versus cemented total knee arthroplasty (TKA) prostheses. This includes the assessment of early revision surgery due to aseptic loosenings and periprosthetic joint infections (PJIs). Studies have not always taken into account the impact of comorbidities, such as diabetes, obesity, and tobacco. Therefore, we compared revisions in a large population of patients undergoing cemented or cementless TKAs at 90days, 1year, and 2years. A review of an administrative claims database was used to identify patients undergoing primary TKA, either cementless (n = 8,890) or cemented (n = 215,460), from October 1, 2015 to October 31, 2020. Revision surgery for PJI and aseptic loosening were identified with diagnosis and associated procedural codes at 90days, 1year, and 2years and then compared between groups. A propensity matched-analysis was performed for age, sex, Charles Comorbidity Index (CCI) > 3, alcohol abuse, tobacco use, obesity, and diabetes. Chi square tests assessed statistical significance of differences in the matched cohorts using odds ratios (ORs) with 95% confidence intervals (CIs). A P < 0.05 was defined as statistically significant. Cementless TKA was associated with similar revisions rates due to PJIs at 90days (OR, 1.04, 95% CI 0.79-1.38, p = 0.83), 1year (OR, 0.93, 95% CI 0.75-1.14, p = 0.53, and 2years (OR, 0.87, 95% CI 0.73-1.05, p = 0.17) in comparison to the cemented TKA cohort. The odds ratio of revision due to aseptic loosening was similar as well at 90days (OR, 0.67, 95% CI 0.34-1.31, 0.31), 1year (OR, 1.09, 95% CI 0.73-1.61, p = 0.76), and 2years (OR, 1.00, 95% CI 0.73-1.61, p = 0.99). This study found a comparable risk of PJI and aseptic loosening in cementless and cemented TKA when controlling for several comorbidities, such as tobacco, diabetes, and alcohol. Therefore, with proper patient selection, cementless TKAs can be performed with expectation of low risks of infections and aseptic loosenings.

High rates of vitamin D insufficiency among patients presenting for total knee arthroplasty.

Widely varying prevalence of vitamin D deficiency has been reported in patients presenting for total knee arthroplasty (TKA). The primary aim of this study was to determine vitamin D levels in TKA patients and to compare to patients already routinely evaluated for vitamin D levels, patients with fragility fractures of the distal radius (DRF). There is significant overlap between patients presenting for TKA and with DRF, both in terms of medical comorbidities and overall health status, making these populations suitable comparative cohorts. Wefound that all patients presenting for TKA consultation had vitamin D insufficiency and 33% had vitamin D deficiency, compared to only 37% and 14% in the DRF cohort, a patient population routinely evaluated for vitamin D due to the high risk of deficiency. Furthermore, patients with DRF had higher levels of vitamin D before (38 ± 16 vs. 23 ± 5) and after vitamin D supplementation (39 ± 17 vs. 33 ± 10), suggesting that patients presenting for TKA are at even higher risk of vitamin D insufficiency than patients presenting with DRF. Reassuringly, supplementation successfully corrected 39.0% and 55.8% of patients in the DRF and TKA cohorts, respectively.

Preoperative Bladder Scanning Can Predict Postoperative Urinary Retention Following Total Joint Arthroplasty.

As total joint arthroplasty (TJA) moves to the outpatient setting, it is becoming clear that postoperative urinary retention (POUR) is a potential impediment to same-day discharge. Although risk factors for POUR have been widely studied, the lack of their clinical utility warrants investigation of specific preoperative factors that can assist in surgical planning and patient optimization. The purpose of the current study was to determine whether preoperative symptom surveys and bladder scanning are useful tools in identifying POUR risk. We performed a prospective analysis of patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) at a high-volume orthopaedic hospital between December 1, 2020, and September 30, 2021. A total of 507 patients (324 female and 183 male) undergoing TJA completed the American Urological Association (AUA) symptom index preoperatively and then again at 14 and 64 days postoperatively. Post-void bladder scans were obtained in the immediate preoperative setting. POUR was defined as a bladder volume of >500 mL that required catheterization. Chi-square and quintile analysis were used to compare bladder scanning volumes, and Student t tests were used to compare AUA scores. The rate of POUR was 37% (66 female and 34 male) and 23% (37 female and 19 male) in the TKA and THA groups, respectively. Increasing post-void residual volume (PVRV) measured on preoperative bladder scanning was found to be predictive of POUR. Among the TKA cohort, younger age and lower body mass index were also associated with increased catheterization, although age was not statistically significant. The AUA symptom survey was not found to correlate with POUR in either population. There was a predictable and exponential increase in the rate of catheterization as preoperative PVRV increased from 50 to 200 mL. The AUA symptom score showed no utility in predicting POUR in our study population. We propose that preoperative bladder ultrasonography become standard practice in TJA, especially among patients scheduled for same-day discharge. Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

The Fate of Unresurfaced Patellae in Contemporary Total Knee Arthroplasty: Early to Midterm Results

BackgroundLeaving the patella unresurfaced in total knee arthroplasty (TKA) has increased significantly over the past decade in the United States, likely due to modern patella-friendly implants, complications with resurfacing, and the knowledge that historical studies were scientifically confounded. This study evaluated revision-free survivorship out to 8.5 years in a cohort of contemporary primary TKAs with patella-friendly femoral components and unresurfaced patellae. MethodsA total of 1,053 consecutive primary TKAs with unresurfaced patellae were retrospectively reviewed. A selective patellar nonresurfacing protocol was used for all cases. Kaplan-Meier survivorship estimates were calculated based on patellar revision and the latest follow-up. An aggressive lateral patellar facetectomy was performed in 78% (823 of 1,053) of cases. The cohort was 62% women and 43% American Society of Anesthesiologists physical status classification I or II with a mean age and body mass index of 65 years (range, 35 to 94) and 35 kg/m2 (range, 18 to 65), respectively. ResultsA total of 4 (0.4%, 4 of 1,053) unresurfaced patellae were revised. Three were resurfaced as part of other procedures: 2 for global instability and one for aseptic loosening at a mean of 1.6 years; and one patella was resurfaced by an outside surgeon for unexplained pain. The all-cause revision-free survivorship estimate specifically related to the patella was 98.9% (95% confidence interval, 98 to 100) out to 8.5 years. No significant difference in survivorship was related to patellae with or without a lateral patellar facetectomy (99.5 versus 98.1%, P ≥ .191); however, 3 of 4 patellar revisions occurred in TKAs without a lateral patellar facetectomy (P = .035). ConclusionsThe results of this study demonstrate excellent revision-free survivorship related to unresurfaced patellae, particularly when a lateral facetectomy was performed. These early to midterm results using modern patella-friendly femoral components are promising and comparable to resurfaced patellae in the literature. Level of EvidenceIV.

Strengthening Quality Measurement to Predict Success for Total Knee Arthroplasty: Results from a Nationally Representative Total Knee Arthroplasty Cohort.

When performed well on appropriate patients, total knee arthroplasty (TKA) can dramatically improve quality of life. Patient-reported outcome measures (PROMs) are increasingly used to measure outcome following TKA. Accurate prediction of improvement in PROMs after TKA potentially plays an important role in judging the surgical quality of the health-care institutions as well as informing preoperative shared decision-making. Starting in 2027, the U.S. Centers for Medicare & Medicaid Services (CMS) will begin mandating PROM reporting to assess the quality of TKAs. Using data from a national cohort of patients undergoing primary unilateral TKA, we developed an original model that closely followed a CMS-proposed measure to predict success, defined as achieving substantial clinical benefit, specifically at least a 20-point improvement on the Knee injury and Osteoarthritis Outcome Score, Joint Arthroplasty (KOOS, JR) at 1 year, and an enhanced model with just 1 additional predictor: the baseline KOOS, JR. We evaluated each model's performance using the area under the receiver operator characteristic curve (AUC) and the ratio of observed to expected (model-predicted) outcomes (O:E ratio). We studied 5,958 patients with a mean age of 67 years; 63% were women, 93% were White, and 87% were overweight or obese. Adding the baseline KOOS, JR improved the AUC from 0.58 to 0.73. Ninety-four percent of those in the top decile of predicted probability of success under the enhanced model achieved success, compared with 34% in its bottom decile. Analogous numbers for the original model were less discriminating: 77% compared with 57%. Only the enhanced model predicted success accurately across the spectrum of baseline scores. The findings were virtually identical when we replicated these analyses on only patients ≥65 years of age. Adding a baseline knee-specific PROM score to a quality measurement model in a nationally representative cohort dramatically improved its predictive power, eliminating ceiling and floor effects and mispredictions for readily identifiable patient subgroups. The enhanced model neither favors nor discourages care for those with greater knee dysfunction and requires no new data collection. Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Life Expectancy of Patients Undergoing Total Knee Arthroplasty: Comparison With General Population.

This study aimed to analyze the life expectancy and cause of death in osteoarthritis (OA) patients who underwent total knee arthroplasty (TKA) and to identify risk factors that affect long-term mortality rate after TKA. Among 601 patients, who underwent primary TKA due to OA by a single surgeon from July 2005 to December 2011, we identified patients who died after the operation using data obtained from the National Statistical Office of Korea. We calculated 5-, 10-, and 15-year survival rates of the patients and age-specific standardized mortality ratios (SMRs) compared to general population of South Korea according to the causes of death. We also identified risk factors for death. The 5-year, 10-year, and 15-year survival rates were 94%, 84%, and 75%, respectively. The overall age-specific SMR of the TKA cohort was lower than that of the general population (0.69; P < 0.001). Cause-specific SMRs for circulatory diseases, neoplasms, and digestive diseases after TKA were significantly lower than those of the general population (0.65, 0.58, and 0.16, respectively; all P < 0.05). Male gender, older age, lower body mass index (BMI), anemia, and higher Charlson comorbidity index (CCI) were significant factors associated with higher mortality after TKA. TKA is a worthwhile surgery that can improve life expectancy, especially from diseases of the circulatory system, neoplasms, and digestive system, in patients with OA compared to the general population. However, careful follow-up is needed for patients with male gender, older age, lower BMI, anemia, and higher CCI, as these factors may increase long-term mortality risk after TKA. III.

Total hip and knee arthroplasty in HIV- and HCV-positive hemophilia patients: short term follow-up of 14 patients

BackgroundHaemophilic arthropathy (HA) is a common comorbidity of haemophilia. Some people with haemophilia (PWH) were human immunodeficiency virus (HIV)-positive. Arthroplasty is an effective treatment for end-stage HA. This study was carried out to report the effectiveness and satisfaction following total hip arthroplasty (THA) or total knee arthroplasty (TKA) in PWH with HIV.Patients and methodsAll patients with haemophilia and HIV undergoing THA or TKA in our centre from January 2015 to June 2020 were reviewed. All patients were followed for at least twenty-four months. The improvements in postoperative indicators were evaluated at the latest follow-up, including the Visual Analogue Scale (VAS) score, range of motion (ROM), and validated joint scores such as Knee Society Score (KSS; clinical and functional) and Harris Hip Score (HHS). The complications and satisfaction were analysed likewise. Those were utilized to weigh the risks and benefits of the procedure in the population.ResultsFourteen patients (7 hips and 14 knees) were included in the study. The follow-up of the THA cohort was 53.3 months (range, 27–82) and the TKA cohort was 50.1 months (range, 25–85), respectively. The average VAS score was ameliorated from 7.3 to 3.0 and 6.6 to 2.8 in the two groups (P < .001, respectively). Similarly, two cohorts (THA and TKA) showed statistically significant changes in the extension and flexion ROM between the preoperative and the latest follow-up (P < .05, P < .001, respectively). Besides, statistically significant differences between the preoperative and final follow-up values of HHS (from 41.6 to 82.3), clinical KSS (from 34.8 to 72.8), and functional KSS (from 42.9 to 73.2) were observed (P < .001, respectively). Notably, there were 4 complications noted among 21 arthroplasties performed, giving a 19.0% complication rate. Based on the satisfaction score, the majority of patients were optimistic about the arthroplasty.ConclusionGiven these findings, THA or TKA of the PWH with HIV is a worthwhile procedure and can be performed by an experienced and collaborative multidisciplinary team in a tertiary centre with a good haemophilia care system.

In Vivo Weight-Bearing Kinematics for Constrained Versus Traditional Bicruciate Stabilized Total Knee Arthroplasty Cohorts Compared to the Normal Knee

BackgroundConstrained inserts in total knee arthroplasty (TKA) may offer additional stability, but can this insert type allow unrestricted movements or will the extra conformity cause kinematic conflict with the cam-post mechanism in deeper flexion? The objective of this study was to evaluate the weight-bearing kinematics of both traditional and constrained bicruciate stabilized (BCS) TKA inserts to determine if the rollback induced by the cam-post mechanism will work in unison with the constrained polyethylene insert. MethodsThis study used previously published 3-dimensional model fitting techniques to compare weight-bearing flexion and femoro-tibial condylar motion patterns for 20 patients who had a traditional insert, 20 patients who had a constrained insert, and 10 previously published nonimplanted knees, all performing a deep knee bend activity while under fluoroscopic surveillance. ResultsThe results from this study indicate that subjects having a bicruciate stabilized TKA experienced similar postoperative kinematics for both constrained and unconstrained insert options, comparable to normal knees. ConclusionsSubjects in this study having either a constrained or traditional insert experienced progressive rollback of both condyles, with the lateral condyle rolling more posterior than the medial condyle, leading to axial rotation. Although less in magnitude, these results were comparable to the normal knee in pattern, indicating that kinematic conflict did not occur for subjects having a constrained insert.

Taux de survie à 20 ans d’une prothèse totale de genou postérostabilisée mono-opérateur dans une population asiatique

IntroductionAs life expectancy has improved, the potential number of revision candidates is also expected to increase among patients who have undergone a total knee arthroplasty (TKA). The longevity of modern posterior stabilized knee prostheses after 20 years of use has not been well documented, especially in Asian populations that require a deeper flexion range due to a floor-based lifestyle. Hypothesis(1) The implant longevity regarding mechanical failures such as aseptic loosening and polyethylene (PE) wear would vary over a longer follow-up depending on the age groups; and (2) there would be unique risk factors for revision surgery in an Asian TKA cohort. Material and methodsWe conducted this age-stratified survival analysis in a consecutive series of 368 NexGen Legacy Posterior Stabilized (LPS) TKAs performed by a single surgeon. These cases were divided into four age groups (< 60 years, early 1960s, late 1960s, and ≥ 70 years). The implant longevity against aseptic mechanical failures was calculated using the Kaplan-Meier method. The revision surgery risk was evaluated using postoperative factors including a deep flexion capability(> 135°), and postoperative mechanical alignments. ResultsOverall survivorship was significantly lower in the youngest groups than other groups (Log-rank test, p=0.001). The cumulative 20-year implant longevity was more than 95% in the two oldest groups, but less than 60% in the youngest group. It was notable that the post-TKA implant longevity was not apparent up to 10 years between the age groups (p=0.073∼0.458). Aseptic loosening was observed with an earlier onset (3.1 to 18.9 years) trend than PE wear (9.8∼17.9 years), with most cases arising in the youngest groups. Flexion limitation and varus alignment were significant risks to aseptic loosening and PE wear (Cox proportional hazard regression: p=0.001 and 0.045, respectively). DiscussionA younger age (< 60 years), inability of postoperative deep flexion, and varus alignment were significant risk factors for aseptic loosening and PE wear after modern PS design in this Asian cohort. The difference in postoperative longevity affected by these factors was not obvious during the first 10 years but emerged over a second decade. Level of proofIII; retrospective cohort study.

Differences in Regional Anesthesia Utilization by Hospital Region in the United States.

Regional anesthesia has been associated with improved postoperative outcomes. Disparities in regional anesthesia utilization exist; however, no studies have examined utilization rates as a function of hospital region. A national hospital database (Hospital Corporation of America {HCA}) was queried for patients aged 18 years or older that received selected surgical procedure codes between January 2016 and June 2021. Surgical procedures included were total knee arthroplasty (TKA), total shoulder arthroplasty (TSA), anterior cruciate ligament reconstruction (ACLR), carpal tunnel release, total abdominal hysterectomy (TAH), open reduction and internal fixation (ORIF) of the ankle, and arteriovenous (AV) fistula creation. Regional anesthesia was defined as any form of neuraxial and/or peripheral nerve blocks. Basic summary statistics were utilized to calculate the rates of regional anesthesia (RA), and chi-squared analyseswere calculated to determine significant differences in the rate of RA utilization. There were 52,068 patients included in this study, of which 2,114 (4.1%) received RA. The greatest RA rates were for TSA (5.8%), TKA (4.5),and anterior cruciate ligament reconstruction (ACLR) (3.6%), whereas the lowest RA rate was for TAH (1.1%). For the TKA cohort, the Midwest had a significantly greater utilization rate than the South or West (10.9% vs. 4.8% or 3.1%, p<0.001). The Midwest also had the highest utilization rate in the ACLR cohort (8.1%, p<0.001), TAH cohort (16.7%, p<0.001), and AV fistula cohort (6.4%, p<0.001). For the carpal tunnel cohort, the West had the highest utilization rate (11.8% vs. 8.1%, 1.1%, 0%, p<0.001). The West region also had the highest utilization rate for the ankle ORIF (7.8%, p<0.001). No significant differences were found by region for TSA (p=0.31). Significant variations in RA utilization rates were found by region, with the West having the highest utilization for ankle ORIF and carpal tunnel, and the Midwest having the highest rate for TKA, ACLR, TAH, and AV fistula.

Complications and Safety of Simultaneous Bilateral Total Knee Arthroplasty: A Patient Characteristic and Comorbidity-Matched Analysis.

Total knee arthroplasty (TKA) is a highly successful surgical procedure that decreases pain and improves function. Many patients who undergo TKA may require surgical intervention on both extremities because of bilateral osteoarthritis. The purpose of this study was to evaluate the safety of simultaneous bilateral TKA compared with that of unilateral TKA. Patients who underwent unilateral or simultaneous bilateral primary, elective TKA from 2015 to 2020 were identified using the Premier Healthcare Database. Subsequently, the simultaneous bilateral TKA cohort was matched to the unilateral TKA cohort in a 1:6 ratio by age, sex, race, and presence of pertinent comorbidities. Patient characteristics, hospital factors, and comorbidities were compared between the cohorts. The 90-day risks of postoperative complications, readmission, and in-hospital death were assessed. Differences were assessed using univariable regression, and multivariable regression analyses were performed to account for potential confounders. Overall, 21,044 patients who underwent simultaneous bilateral TKA and 126,264 matched patients who underwent unilateral TKA were included. After accounting for confounding factors, patients who underwent simultaneous bilateral TKA demonstrated a significantly increased risk of postoperative complications, including pulmonary embolism (adjusted odds ratio [OR], 2.13 [95% confidence interval (CI), 1.57 to 2.89]; p < 0.001), stroke (adjusted OR, 2.21 [95% CI, 1.42 to 3.42]; p < 0.001), acute blood loss anemia (adjusted OR, 2.06 [95% CI, 1.99 to 2.13]; p < 0.001), and transfusion (adjusted OR, 7.84 [95% CI, 7.16 to 8.59]; p < 0.001). Patients who underwent simultaneous bilateral TKA were at increased risk of 90-day readmission (adjusted OR, 1.35 [95% CI, 1.24 to 1.48]; p < 0.001). Simultaneous bilateral TKA was associated with increased rates of complications including pulmonary embolism, stroke, and transfusion. Orthopaedic surgeons and patients should consider these potential complications when contemplating simultaneous bilateral TKA. When simultaneous bilateral TKA is pursued, patient counseling and thorough medical optimization should be performed. Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Poster 363: Post-Operative Protein Supplementation following Orthopaedic Surgery: A Systematic Review

Objectives: Decreased mechanical loading after orthopaedic surgery predisposes patients to develop muscle atrophy. The purpose of the study was to assess whether oral protein supplementation can help decrease postoperative muscle atrophy and/or improve patient outcomes following orthopaedic surgery. Methods: A systematic review of the literature was performed following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The review was registered with the Prospective Register of Systematic Reviews (PROSPERO). A search of the PROSPERO registration did not identify similar prior systematic reviews or meta-analyses. Databases were searched during April 2021 and included: MEDLINE (Pubmed), Embase, Scopus, and Web of Science. Each search contained a combination of the following terms: “orthopaedic procedures” AND “protein” OR “amino acid” AND “dietary supplements” OR “supplementation” OR “supplement.” Orthopaedic procedures were listed individually using the PubMed index of orthopaedic procedures, as well as using the mesh function to extract articles with orthopaedic procedures listed as keywords. Eligibility Criteria The principal inclusion criteria consisted of randomized controlled trials evaluating protein or amino acid regimens as a measure to counteract muscle atrophy following orthopaedic surgery. Articles that evaluated other forms of dietary supplementation or non-orthopaedic procedures were excluded. Control groups included either placebo or a natural history control (i.e. routine post-operative protocol). The scope of surgery was intentionally left broad, to allow for a comparison of protein supplementation effectiveness across different surgical interventions. Each study’s reference list was manually reviewed for additional articles to prevent unintentional exclusion of studies. Two reviewers independently assessed all articles identified by the search strategy and applied the eligibility criteria. Data Extraction The content extracted from each article included: (1) demographic data, (2) protein supplement regimen used, (3) outcomes, (4) complications, and (5) length of follow up. Primary outcomes included functional or physiologic measures of muscle atrophy or strength. Secondary outcomes included patient satisfaction and time to return to sport or work. Data Analysis Quality assessment of studies was performed using Modified Coleman Methodology Scoring (MCMS). Heterogeneity of study design was noted including differences in protocols, measurement techniques, and outcomes measured, which prevented an adequate statistical comparison for meta-analysis. Results: Fourteen studies including 611 patients (224 male, 387 female) were analyzed (Figure 1). Four surgical cohorts were identified: Anterior cruciate ligament reconstruction (ACLR), total hip arthroplasty (THA), hip fractures (THA, revision THA, hip resurfacing), and total knee arthroplasty (TKA). The ACLR, THA, and hip fracture cohorts were each composed of 3 studies, while there were 5 studies in the TKA cohort. Average length of follow-up was 9 weeks for ACLR, 7 weeks for THA, 10 weeks for hip fracture, and 7 weeks for TKA. Protein supplementation included various combinations of essential amino acids in tablet form or whey protein powder. Placebo supplements were most commonly an isocaloric carbohydrate tablet or powder. Protein supplementation was reported to have beneficial effects across all types of identified surgeries. The primary benefit was decreased muscle atrophy measured by muscle cross sectional area. The most significant difference in muscle atrophy was observed in the final week of follow-up for the majority of studies (average follow up was 8 weeks). Multiple studies also demonstrated improved functional measures, including increased muscle function measured by isokinetic muscle strength. Of note, most participants were involved in some form of formal physical therapy for varying durations after surgery, but this was not standardized across all studies. There were no significant increases in side effects reported comparing protein supplementation cohorts to controls. Of the included investigations, only 2 studies (both for hip fracture) had participants follow a standardized diet. Average MCMS scores for each surgical cohort were as follows: ACLR 55 (fair), TKA 55 (fair), THA 46 (poor), hip fracture 44 (poor). Conclusions: In conclusion, protein supplementation appears to have beneficial effects on mitigating muscle atrophy in the postoperative period following ACLR, THA, TKA, and surgical treatment of hip fracture. This response often correlates with improved functional measures and quicker achievement of rehabilitation benchmarks. Further research is needed to establish standardized supplementation regimens and guidelines for improving clinical outcomes in the postoperative period.

Twenty-year survivorship cohort study of total knee arthroplasty in Asian patient using a single posterior-stabilized implant performed by a single surgeon

IntroductionAs life expectancy has improved, the potential number of revision candidates is also expected to increase among patients who have undergone a total knee arthroplasty (TKA). The longevity of modern posterior stabilized knee prostheses after 20 years of use has not been well documented, especially in Asian populations that require a deeper flexion range due to a floor-based lifestyle. HypothesisFirstly, the implant longevity regarding mechanical failures such as aseptic loosening and polyethylene (PE) wear would vary over a longer follow-up depending on the age groups; and secondly there would be unique risk factors for revision surgery in an Asian TKA cohort. Material and methodsWe conducted this age-stratified survival analysis in a consecutive series of 368 NexGen Legacy Posterior Stabilized (LPS) TKAs performed by a single surgeon. These cases were divided into four age groups (< 60 years, early 60s, late 60s, and ≥ 70 years). The implant longevity against aseptic mechanical failures was calculated using the Kaplan-Meier method. The revision surgery risk was evaluated using postoperative factors including a deep flexion capability (> 135̊), and postoperative mechanical alignments. ResultsOverall survivorship was significantly lower in the youngest groups than other groups (Log-rank test, p=0.001). The cumulative 20-year implant longevity was more than 95% in the two oldest groups, but less than 60% in the youngest group. It was notable that the post-TKA implant longevity was not apparent up to 10 years between the age groups (p=0.073∼0.458). Aseptic loosening was observed with an earlier onset (3.1 to 18.9 years) trend than PE wear (9.8∼17.9 years), with most cases arising in the youngest groups. Flexion limitation and varus alignment were significant risks to aseptic loosening and PE wear (Cox proportional hazard regression: p=0.001 and 0.045, respectively). DiscussionA younger age (< 60 years), inability of postoperative deep flexion, and varus alignment were significant risk factors for aseptic loosening and PE wear after modern PS design in this Asian cohort. The difference in postoperative longevity affected by these factors was not obvious during the first 10 years but emerged over a second decade. Level of proofIII; retrospective cohort study.

Restoration of the native tibial joint line obliquity in total knee arthroplasty with inverse kinematic alignment does not increase knee adduction moments.

Patient-specific alignment in total knee arthroplasty (TKA) has shown promising patient-reported outcome measures; however, the clinical and biomechanical effects of restoring the native knee anatomy remain debated. The purpose of this study was to compare the gait pattern between a mechanically aligned TKA cohort (adjusted mechanical alignment-aMA) and a patient-specific alignment TKA cohort (inverse kinematic alignment-iKA). At two years postoperatively, the aMA and iKA groups, each with 15 patients, were analyzed in a retrospective case-control study. All patients underwent TKA with robotic assistance (Mako, Stryker) through an identical perioperative protocol. The patients' demographics were identical. The control group comprised 15 healthy participants matched for age and gender. Gait analysis was performed with a 3D motion capture system (VICON). Data collection was conducted by a blinded investigator. The primary outcomes were knee flexion during walking, knee adduction moment during walking and spatiotemporal parameters (STPs). The secondary outcomes were the Oxford Knee Score (OKS) and Forgotten Joint Score (FJS). During walking, the maximum knee flexion did not differ between the iKA group (53.0°) and the control group (55.1°), whereas the aMA group showed lower amplitudes of sagittal motion (47.4°). In addition, the native limb alignment in the iKA group was better restored, and although more in varus, the knee adduction moments in the iKA group were not increased (225Nmm/kg) compared to aMA group (276Nmm/kg). No significant differences in STPs were observed between patients receiving iKA and healthy controls. Six of 7 STPs differed significantly between patients receiving aMA and healthy controls. The OKS was significantly better in patients receiving iKA than aMA: 45.4 vs. 40.9; p = 0.05. The FJS was significantly better in patients receiving iKA than aMA: 84.8 vs. 55.5; p = 0.002. At two years postoperatively, the gait pattern showed greater resemblance to that in healthy controls in patients receiving iKA rather than aMA. The restoration of the native coronal limb alignment does not lead to increased knee adduction moments due to the restoration of the native tibial joint line obliquity. Level III.

Intersurgeon Variability of Minimal Clinically Important Difference for Worsening Achievement Rates After Total Joint Arthroplasty

BackgroundUsing the Patient-Reported Outcome Measurement Information System, we sought to evaluate surgeon performance variability via minimal clinically important difference for worsening (MCID-W) achievement rates in primary and revision total knee and hip arthroplasty. MethodsThis retrospective study analyzed 3,496 primary total hip arthroplasty (THA), 4,622 primary total knee arthroplasty (TKA), 592 revision THA, and 569 revision TKA patients. Patient factors collected included demographics, comorbidities, and Patient-Reported Outcome Measurement Information System physical function short form 10a scores. Surgeon factors collected included caseload, years of experience, and fellowship training. The MCID-W rate was calculated as the percent of patients in each surgeon’s cohort who achieved MCID-W. Distribution was presented via a histogram with associated average, standard deviation, range, and interquartile range (IQR). Linear regressions were performed to evaluate the potential correlation between surgeon- and patient-level factors with MCID-W rate. ResultsThe average MCID-W rates of the surgeons represented in the primary THA and TKA cohorts were 12.7 ± 9.2% (range, 0 to 35.3%; IQR, 6.7 to 15.5%) and 18.0 ± 8.2% (range, 0 to 36%; IQR, 14.3 to 22.0%). The average MCID-W rates among the revision THA and TKA surgeons were 36.0 ± 22.2% (range, 9.1 to 90%; IQR, 25.0 to 41.4%) and 21.2 ± 7.7% (range, 8.1 to 37.0%; IQR, 16.6 to 25.4%). Strong correlations were not found between patient- or surgeon-level factors and MCID-W rate of the surgeon. ConclusionWe demonstrated variance in MCID-W achievement rates across surgeons in both primary and revision joint arthroplasty, independent of patient- or surgeon-level factors.

Assessing the Mortality Rate After Primary Total Knee Arthroplasty: An Observational Study to Inform Future Economic Analysis

BackgroundPrevious research has focused on the perioperative or short-term (<1 year) mortality rate of total knee arthroplasty (TKA), leaving the long-term (>1 year) mortality rate unresolved. In this study, we calculated the mortality rate up to 15 years after primary TKA. MethodsData from the New Zealand Joint Registry from April 1998 to December 2021 were analyzed. Patients aged 45 years or older who underwent TKA for osteoarthritis were included. Mortality data were linked with national records from births, deaths, and marriages. To determine the expected mortality rates in the general population, age-sex-specific life tables from statistics New Zealand were used. Mortality rate was presented as standardized mortality ratios (SMRs) – a comparison of relative mortality rate between the TKA and general populations. In total, 98,156 patients with a median follow-up of 7.25 years (range, 0.00 to 23.74) were included. ResultsOver the entire follow-up period, 22,938 patients (23.4%) had died. The overall SMR for the TKA cohort was 1.08 (95% confidence interval (CI): 1.06 to 1.09), suggesting that TKA patients have an 8% higher mortality rate compared to the general population. However, a reduction in short-term mortality rate was observed for TKA patients up to 5 years post TKA (SMR 5 years post TKA; 0.59 95% CI: 0.57 to 0.60]). On the contrary, a significantly increased long-term mortality rate was observed in TKA patients with greater than 11 years of follow-up, particularly in men over the age of 75 years (SMR 11 to 15 years post TKA for males ≥ 75 years; 3.13 [95% CI: 2.95 to 3.31]). ConclusionThe results suggest a reduction in short-term mortality rate for patients who undergo primary TKA. However, there is an increased long-term mortality rate particularly in men over the age of 75 years. Importantly, the mortality rates observed in this study cannot be causally attributed to TKA alone.

Preoperative Patient Optimization: Outcomes from Elective Total Joint Arthroplasty in a Large US Healthcare System.

Patient factors are known to affect outcomes in arthroplasty surgery. A preoperative program to address modifiable factors may aid in more appropriate patient selection. We sought to assess patient selection and 90-day postoperative outcomes for total joint arthroplasty (TJA) candidates before and after implementation of a preoperative optimization protocol. A retrospective time-trend study using data from an integrated healthcare system's total joint replacement registry was done. The study sample consisted of patients aged 18 years or older who underwent primary elective total hip arthroplasty (THA) and total knee arthroplasty (TKA) for osteoarthritis between 2009 and 2019. Patients were divided into two cohorts: procedures performed from 2009 to 2013 ("preoptimization protocol") and those from 2015 to 2019 ("postoptimization protocol"); 2014 was excluded because an evidence-based preoperative patient optimization protocol was progressively implemented throughout the year. Patient characteristics, optimization factors, and 90-day outcomes (including emergency department [ED] visits, readmission, all-cause revision, deep infection, venous thromboembolism, and mortality) were compared between the two cohorts using the Pearson chi-square test or Wilcoxon test. The study sample included 25,925 THA and 60,484 TKA. In the THA cohort, 10,364 (40.0%) and 15,561 (60.0%) were from the preoptimization and postoptimization cohorts, respectively. The postoptimization THA cohort saw lower rates of ED visits (12.1% vs. 9.4%, P < 0.001) and readmissions (5.6% vs. 3.8%, P < 0.001). In the TKA cohort, 24,054 (39.8%) and 36,430 (60.2%) were from the preoptimization and postoptimization cohorts, respectively. The postoptimization TKA cohort saw lower rates of ED visits (13.1% vs. 11.9%, P < 0.001), readmissions (5.6% vs. 3.0%, P < 0.001), all-cause revisions (0.5% vs. 0.3%, P = 0.003), venous thromboembolism (1.3% vs. 0.9%, P < 0.001), and mortality (0.3% vs. 0.2%, P = 0.011). An evidence-based protocol to improve patient selection based on modifiable patient factors was adopted by orthopaedic surgeons in the system and utilization of the protocol before TJA was associated with fewer postoperative complications over time. Level IV.

Do Patient-Reported Outcomes Reflect Objective Measures of Function? Implications for Total Knee Arthroplasty

BackgroundPatient-reported outcomes (PROs) are used in research, clinical practice, and by federal reimbursement models to assess outcomes for patients who have knee osteoarthritis (OA) and total knee arthroplasty (TKA). We examined a large cohort of patients to determine if commonly used PROs reflect observed evaluation as measured by standardized functional tests (SFTs). MethodsWe used data from the Osteoarthritis Initiative, a 10-year observational study of knee osteoarthritis patients. Two cohorts were examined: 1) participants who received TKA (n = 281) and 2) participants who have native OA (n = 4,687). The PROs included Western Ontario and McMaster Osteoarthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS), 12-Item Short Form Health Survey (SF-12), and Intermittent and Constant Pain Score (ICOAP). The SFTs included 20 m and 400 meter (m) walks and chair stand pace. Repeated measures correlation coefficients were used to determine the relationship between PROs and SFTs. ResultsThe PROs and SFTs were not strongly correlated in either cohort. The magnitude of the repeated measures correlation (rrm) between KOOS, WOMAC, SF-12, and ICOAP scores and SFT measurements in native knee OA patients ranged as follows: 400 m walk pace (0.08 to 0.20), chair stand pace (0.05 to 0.12), and 20 m pace (0.02 to 0.21), all with P < .05. In the TKA cohort, values ranged as follows: 400 M walk pace (0.00 to 0.29), chair stand time (0.02 to 0.23), and 20 M pace (0.03 to 0.30). Due to the smaller cohort size, the majority, but not all had P values < .05. ConclusionThere is not a strong association between PROs and SFTs among patients who have knee OA or among patients who received a TKA. Therefore, PROs should not be used as a simple proxy for observed evaluation of physical function. Rather, PROs and SFTs are complementary and should be used in combination for a more nuanced and complete characterization of outcome.