Time trends in the characteristics of patients undergoing primary total knee arthroplasty

Demographic and Socioeconomic Trends of Patients Undergoing Total Knee Arthroplasty From 2013 to 2022-An Analysis From an Urban Orthopaedic Hospital

BACKGROUND

As worldwide utilization of total knee arthroplasty (TKA) broadens, demographic trends can help make projections to inform access to care. This study aimed to assess the temporal trends in the socioeconomic and medical demographics of patients undergoing TKA.

METHODS

A retrospective review of 15,848 patients who underwent primary, elective TKA at an urban, New York City-based academic medical center between January 2013 and September 2022 was performed. Trends in patients' age, body mass index (BMI), socioeconomic status (SES) (based on median income by patients' ZIP code), race, and Charlson comorbidity index were evaluated using the Mann-Kendall test.

RESULTS

In the last decade, mean patient age (65 to 68 years, P < .001) and Charlson comorbidity index (1.4 to 2.3, P < .001) increased significantly. The proportion of patients who had a BMI ≥ 30 and < 40 increased (43.8 to 51.2%, P = .002), while the proportion of patients who had a BMI ≥ 40 (13.7 to 12.1%, P = .015) and BMI < 30 (42.5 to 36.8%, P = .020) decreased. The distribution of patients' race and SES did not change from 2013 to 2022; Black (18.1 to 16.8%, P = .211) and low SES (12.9 to 11.3%, P = .283) patients consistently represented a minority of TKA patients.

CONCLUSIONS

Over the last decade, the average age and comorbidity burden of TKA patients at our institution have increased. This portends the need for higher levels of preoperative optimization and postoperative management for TKA patients. A decreased prevalence of BMI ≥40 could reflect optimization efforts. However, the consistently low prevalence of Black and low-SES patients suggests that recent payment models did not improve access to care for these populations.

LEVEL OF EVIDENCE

IV.

Trends in Extended Oral Antibiotic Prophylaxis Utilization Following Primary and Revision Total Hip Arthroplasty From 2010 to 2022

BACKGROUND

In patients considered high-risk for infection, extended oral antibiotic (EOA) prophylaxis has been demonstrated to reduce rates of prosthetic joint infection following total hip arthroplasty (THA). Although national guidelines regarding their use have not yet been created, the increase in literature surrounding EOA prophylaxis suggests a potential change in practice patterns. The purpose of this study was to investigate the trends in utilization of EOA prophylaxis following THA from 2010 to 2022 and identify prescription patterns.

METHODS

A total of 646,059 primary THA and 51,879 aseptic revision THA patients were included in this study. Patients who underwent primary or aseptic revision THA between 2010 and 2022 were identified in a national administrative claims database. Rates and duration of EOA prescriptions were calculated. A secondary analysis examined rates of utilization across demographics, including patients considered high risk for infection.

RESULTS

From 2010 to 2022, utilization of EOA increased by 366% and 298% following primary and revision THA, respectively. Of patients prescribed postoperative antibiotics, 30% and 59% were prescribed antibiotics for more than 7 days following primary and revision THA, respectively. Rates of utilization were similar between high-risk individuals and the general population.

CONCLUSIONS

Rates of utilization of EOA prophylaxis after THA have increased significantly since 2010. As current trends demonstrate a wide variation in prescription patterns, including in length of antibiotic duration and in patient population prescribed, guidelines surrounding the use of EOA prophylaxis after THA are necessary to promote antibiotic stewardship while preventing rates of periprosthetic joint infection.

Elective Joint Replacement Among Medicaid Beneficiaries: Utilization and Postoperative Adverse Events by Racial and Ethnic Groups

Hip and knee replacement have been marked by racial and ethnic disparities in both utilization and postoperative adverse events among Medicare beneficiaries, but limited knowledge exists regarding racial and ethnic differences in joint replacement care among Medicaid beneficiaries. To close this gap, this study used Medicaid claims in 2018 and described racial and ethnic differences in the utilization and postoperative adverse events of elective joint replacements among Medicaid beneficiaries. Among the 2,260,272 Medicaid beneficiaries, 5987 had an elective joint replacement in 2018. Asian (0.05%, 95% confidence interval [CI]: 0.03%-0.07%) and Hispanic beneficiaries (0.12%, 95% CI: 0.07%-0.18%) received joint replacements less frequently than American Indian and Alaska Native (0.41%, 95% CI: 0.27%-0.55%), Black (0.33%, 95% CI: 0.19%-0.48%), and White (0.37%, 95% CI: 0.25%-0.50%) beneficiaries. Black patients demonstrated the highest probability of 90-day emergency department visits (34.8%, 95% CI: 32.7%-37.0%) among all racial and ethnic groups and a higher probability of 90-day readmission (8.0%, 95% CI: 6.9%-9.0%) than Asian (3.4%, 95% CI: 0.7%-6.0%) and Hispanic patients (4.4%, 95% CI: 3.4%-5.3%). These findings indicate evident disparities in postoperative adverse events across racial and ethnic groups, with Black patients demonstrating the highest probability of 90-day emergency department visits. This study represents an initial exploration of the racial and ethnic differences in joint replacement care among Medicaid beneficiaries and lay the groundwork for further investigation into contributing factors of the observed disparities.

Global mapping of institutional and hospital-based (Level II-IV) arthroplasty registries: a scoping review

PURPOSE

Four joint arthroplasty registries (JARs) levels exist based on the recorded data type. Level I JARs are national registries that record primary data. Hospital or institutional JARs (Level II-IV) document further data (patient-reported outcomes, demographic, radiographic). A worldwide list of Level II-IV JARs must be created to effectively assess and categorize these data.

METHODS

Our study is a systematic scoping review that followed the PRISMA guidelines and included 648 studies. Based on their publications, the study aimed to map the existing Level II-IV JARs worldwide. The secondary aim was to record their lifetime, publications' number and frequency and recognise differences with national JARs.

RESULTS

One hundred five Level II-IV JARs were identified. Forty-eight hospital-based, 45 institutional, and 12 regional JARs. Fifty JARs were found in America, 39 in Europe, nine in Asia, six in Oceania and one in Africa. They have published 485 cohorts, 91 case-series, 49 case-control, nine cross-sectional studies, eight registry protocols and six randomized trials. Most cohort studies were retrospective. Twenty-three per cent of papers studied patient-reported outcomes, 21.45% surgical complications, 13.73% postoperative clinical and 5.25% radiographic outcomes, and 11.88% were survival analyses. Forty-four JARs have published only one paper. Level I JARs primarily publish implant revision risk annual reports, while Level IV JARs collect comprehensive data to conduct retrospective cohort studies.

CONCLUSIONS

This is the first study mapping all Level II-IV JARs worldwide. Most JARs are found in Europe and America, reporting on retrospective cohorts, but only a few report on studies systematically.

Disease burden of and expectations from surgery in patients prior to total knee arthroplasty: Results of the prospective FInGK study

BACKGROUND

Disease burden in patients prior to total knee arthroplasty (TKA) varies widely between studies and countries. We aimed to characterize individuals undergoing TKA and examine their expectations from the surgery, focusing on variations in disease burden.

METHODS

Consecutive patients undergoing primary TKA in a German university hospital were recruited. A questionnaire including information on disease burden, preoperative expectations from surgery, health care utilization, demography, and socioeconomics was collected one day prior to surgery and linked to data from medical records. Patients were categorized into disease burden quartiles using the Western Ontario and McMaster Universities Osteoarthritis Index' (WOMAC) total score. Subsequently, study population's characteristics and expectations from surgery were analyzed stratified by disease burden.

RESULTS

A total of 196 patients were included (41 % male; mean age: 68.2 years). The median WOMAC was 52.0 (IQR: 41.0-58.0). Patients in Q1 were more often males (Q1: 63 % vs Q4: 29 %) and had a shorter duration of complaints with the impaired knee. They were also less restricted in social participation, reported less often signs of depression, and were less often treated with physiotherapy (Q1: 27 % vs Q4: 54 %). Furthermore, expectations from surgery were highest in patients with a low disease burden.

CONCLUSION

We found large variations in disease burden with a considerable number of patients undergoing TKA whose functional capacity is still maintained and for which guideline-recommended conservative treatment options are not fully exhausted. Further research on this subgroup as well as establishing an international consensus on specific thresholds for TKA indication are needed.

Not All Patients Need Supervised Physical Therapy After Primary Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

Although postoperative physical therapy (PT) has long been considered essential to successful total knee arthroplasty (TKA) recovery, recent literature has suggested that unsupervised home exercise regimens may offer similar benefits to formal supervised sessions. We aimed to compare objectively measured physical function and subjective patient-reported outcomes (PROs) between primary TKA patients who received formal supervised physical therapy sessions and those who received unsupervised home exercise regimens after discharge. Six electronic databases were queried to identify randomized controlled trials comparing supervised physical therapy to unsupervised home exercise regimens in primary TKA patients after discharge. Outcomes of interest included change from baseline in objective measures (knee flexion range of motion (ROM), lower extremity strength, and aerobic capacity) and PROs (physical function and quality of life scores). These outcomes were subdivided into short-term (<6 months from surgery; closest data point to three months is used if multiple measurements were made in this time period) and long-term (≥6 months from surgery; closest data point to 12 months is used if multiple measurements were made in this time period) assessments. A total of 1,884 cases performed in 11 studies were included in this review. There were no significant differences between cohorts with regard to short-term knee flexion ROM (p = 0.7), lower extremity strength (p = 0.6), or patient-reported quality of life (p = 0.5), as well as long-term knee flexion ROM (p = 0.7), patient-reported quality of life (p = 0.2), or patient-reported physical outcome scores (p = 0.3). A small difference in short-term patient-reported physical outcomes was observed in favor of the supervised cohort (standardized mean difference (SMD): 0.3 (95% confidence interval (CI): 0.01, 0.6); I2 = 82%; p = 0.04). Formal supervised physical therapy regimens do not confer clinically significant benefits over unsupervised home exercise regimens following primary TKA. The routine use of supervised physical therapy after discharge may not be warranted. Further study is needed to determine the subset of patients that may benefit from supervised care.

Chronic Obstructive Pulmonary Disease Associated with Prolonged Opiate Use, Increased Short-Term Complications, and the Need for Revision Surgery following Total Knee Arthroplasty

Chronic obstructive pulmonary disease (COPD) is a condition which causes a substantial burden to patients, physicians, and the health care system at large. Medical comorbidities are commonly associated with adverse health outcomes in the postoperative period. Here, we present a large database review of patients undergoing total knee arthroplasty (TKA) to determine the effect of COPD on patient outcomes. The PearlDiver database was queried for all patients who underwent TKA between 2007 and the first quarter of 2017. Medical complications, surgical complications, 30-day readmission rates, revision rates, and opioid utilization were assessed at various intervals following TKA among patients with and without COPD. Multivariable regression was used to calculate adjusted odds ratios controlling for age, sex, and medical comorbidities. A total of 46,769 TKA patients with COPD and 120,177 TKA patients without COPD were studied. TKA patients with COPD experienced increased risk of 30-day readmission (40.8% vs. 32.2%, p < 0.0001), 30-day total medical complications (10.2% vs. 7.0%, p < 0.0001), prosthesis explanation at 6 months (0.4% vs. 0.2, p = 0.0130), 1 year (0.6% vs. 0.3%, p = 0.0005), and 2 years (0.8% vs. 0.5%, p = 0.0003), as well as an increased rate of revision (p < 0.0046) compared to TKA patients without COPD. Opioid utilization of TKA patients with COPD was greater significantly than that of TKA patients without COPD at 3, 6, and 12 months. Patients with COPD have an increased risk for medical and surgical complications, readmission, and prolonged opioid use following TKA.

Cemented Total Knee Arthroplasty Shows Less Blood Loss but a Higher Rate of Aseptic Loosening Compared With Cementless Fixation: An Updated Meta-Analysis of Comparative Studies

BACKGROUND

The aim of this study was to update the current evidence on functional outcomes, complications, and reoperation rates between cemented and cementless total knee arthroplasty (TKA) by evaluating comparative studies published over the past 15 years.

METHODS

The PubMed, MEDLINE, Scopus, and the Cochrane Central databases were used to search keywords and a total of 18 studies were included. Random and fixed effect models were used for the meta-analysis of pooled mean differences (MDs) and odds ratios (ORs).

RESULTS

A total of 5,222 patients were identified with a mean age of 64.4 ± 9.4 and 63 ± 8.6 years for the cemented and cementless TKA groups, respectively. The mean follow-up was 107.9 ± 30 and 104.3 ± 10 months for the cemented and cementless TKA groups, respectively. Cemented TKA showed a significantly greater postoperative Knee Society Score (MD = -0.95, 95% CI [-1.57, 0.33], P = .003) and range of motion (MD = -1.09, 95% CI [-1.88, -0.29], P = .0007), but no differences in other outcome scores were found. The incidence of periprosthetic joint infection, radiolucent lines, instability, and polyethylene wear was also comparable. Cemented TKA showed less perioperative blood loss (SMD = -438.41, 95% CI [-541.69, -35.14], P < .0001) but a higher rate of manipulation under anesthesia (OR = 3.39, 95% CI [1.64, 6.99], P = .001) and aseptic loosening (OR = 1.62, 95% CI [1.09, 2.41], P = .02) than cementless TKA. No differences were found in terms of the reoperation rate.

CONCLUSION

When cemented and cementless fixations are compared in primary TKA, comparable functional outcomes and reoperation rates can be achieved. Cemented TKA showed less blood loss but a higher rate of manipulation under anesthesia and aseptic loosening.

Extended Postoperative Prophylactic Antibiotics for Primary and Aseptic Revision Total Joint Arthroplasty: A Systematic Review

INTRODUCTION

Limited literature is available about the effects of extended (>24 hours) antibiotic use after primary and aseptic revision total joint arthroplasty (TJA) on rates of periprosthetic joint infection (PJI). The purpose of this study was to systematically review the outcomes of extended prophylactic antibiotic use.

METHODS

A systematic search on PubMed and EMBASE databases was done in August 2021 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles that met inclusion criteria were screened by two separate authors. Basic patient demographics, route of delivery, type, dose, frequency of the antibiotic, rates of PJI, and length of stay were extracted.

RESULTS

A total of 11 articles published from 1979 to 2021 were included in the final analysis. Two studies evaluated aseptic revisions, seven evaluated primary TJA, and two studies evaluated both. Five studies were randomized controlled trials, one multicenter nonrandomized trial, and five retrospective cohort studies. All 11 studies used a cephalosporin or a penicillin antibiotic in both the control and cohort groups. Five studies used intravenous (IV) antibiotics, one study used oral (PO) antibiotics, and the other five studies used both IV and PO antibiotics. Length of stay was reported in three studies, all using IV antibiotics. All 11 studies evaluated rates of PJI, while four studies evaluated included rates of superficial surgical site infections. Four studies showed a statistically significant decrease in PJI when compared with a control group, while seven studies showed no statistically significant difference.

CONCLUSION

There is conflicting evidence regarding the benefit of extended (>24 hours) antibiotics, IV or PO, after TJA. As of now, current guidelines do not support the use of extended antibiotics; future prospective clinical trials are needed to help support these claims.

Total knee arthroplasty in the past three decades: Trends in patient characteristics and implant survivorship

OBJECTIVE

To explore the trends in patient characteristics and implant survivorship (IS) for primary total knee arthroplasty (TKA) over the past three decades.

METHODS

This retrospective study enrolled a total of 635 knees who underwent TKA from 1985 to 2014. They were divided into three groups: group A, 125 knees in 1985-1994; group B, 203 knees in 1995-2004; and group C, 307 knees A in 2005-2014. The patient characteristics and IS were compared.

RESULTS

The mean age of patients undergoing TKA was getting older: 65.3 ± 9.7, 69.1 ± 10.0, and 74.6 ± 8.4 years, in groups A, B, and C, respectively (p = .001). The proportion of patients <60 years old with RA decreased (p < .001), whereas that of patients ≥ 80 years old with OA increased dramatically, it was 7.0%, 14.5%, and 32.0% in groups A, B, and C, respectively (p < .001). The IS free from infection was over 98% in all groups. Alternatively, the IS free from aseptic loosening become better, it was 83.7%, 95.2%, and 98.2% in groups A, B, and C, respectively (p = .014).

CONCLUSIONS

From these trends, we can estimate that the number of patients undergoing TKA will further increase in the future in an aging society.

How Does Tibial Pin Placement in Navigated Total Knee Arthroplasty Affect the Torsional Strength of the Tibia?

INTRODUCTION

Surgical navigation technology has recently become more prevalent for total knee arthroplasty. Surgical navigation typically requires pin placement in the proximal tibia diaphysis to stabilize the bone-tracking hardware, and there have been several recent reports of fractures through these residual navigation pin holes. The objective of this biomechanical study was to determine whether a difference exists in the torsional bone strength of a 5-mm navigation pin hole drilled at a single location in three different orientations: unicortical, bicortical, and transcortical.

METHODS

Biomechanical composite sawbone tibias were used to test four conditions: the intact condition with no holes, a unicortical hole, a bicortical hole, and a transcortical hole through the proximal diaphysis. Seven specimens from each group were tested in external rotation to failure at 1 deg/sec. Torque-to-failure, absorbed energy-to-failure, and rotational angle-to-failure were statistically compared across the four groups.

RESULTS

All specimens failed proximally by spiral oblique fractures. No statistical differences were found between unicortical and bicortical groups in torque-to-failure, energy-to-failure, and angle-to-failure. However, both unicortical and bicortical groups were markedly lower in all measures than the intact group. The transcortical group was markedly lower in all measures than the intact group and both unicortical and bicortical groups.

DISCUSSION

An appropriately placed navigation residual pin hole, either unicortical or bicortical, markedly decreases the torque-to-failure, energy-to-failure, and angle-to-failure of the tibia compared with the intact condition in a synthetic sawbones model. No notable difference was detected between the unicortical and bicortical holes; however, an errant transcortical residual navigation pin hole markedly decreases all measures compared with an appropriately placed unicortical or bicortical hole.

Examination of exclusion criteria in total knee arthroplasty rehabilitation trials: influence on the application of evidence in day-to-day practice

OBJECTIVE

Total knee arthroplasty (TKA) rehabilitation trials use exclusion criteria, which may limit their generalizability in practice. We investigated whether patients seen in routine practice who meet common exclusion criteria recover differently from TKA compared to research-eligible patients. We hypothesized that research-ineligible patients would demonstrate poorer average postoperative function and slower rate of functional recovery compared to research-eligible patients.

METHODS

Patient characteristics and exclusion criteria were extracted and summarized from trials included in the three most recent systematic reviews of TKA rehabilitation. Trial participant characteristics were compared to a clinical dataset of patient outcomes collected in routine TKA rehabilitation. Where possible, individual exclusion criterion from the trials were applied to the clinical dataset to determine "eligible" and "ineligible" groups for research participation. Postoperative functional outcomes including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Timed Up and Go (TUG) were compared between "eligible" and "ineligible" groups using mixed effects models.

RESULTS

2,528 participants from 27 trials were compared to 474 patients from the clinical dataset. Research participants were older, with lower Body Mass Index than patients in the clinical dataset. Many patients in the clinical dataset would be "ineligible" for research participation based upon common exclusion criteria from the trials. Differences were observed in average postoperative functioning between some "eligible" and "ineligible" groups in the clinical dataset. However, no differences were observed in functional recovery rate between groups, except for patients with diabetes whose TUG recovered more slowly than their "eligible" counterparts.

CONCLUSIONS

Many patients in the clinical dataset were "ineligible" for research participation based upon common TKA rehabilitation trial exclusion criteria. However, the postoperative recovery rate did not differ between "eligible" and "ineligible" groups based on individual exclusion criterion-except for individuals with diabetes. This suggests that both clinical and research populations may recover similarly from TKA.

Effect of weight-loss diets prior to elective surgery on postoperative outcomes in obesity: A systematic review and meta-analysis

This systematic review investigated the effects of weight-loss diets before elective surgery on preoperative weight loss and postoperative outcomes in people with obesity. Electronic databases were searched from inception to May 2021. Inclusion criteria were prospective cohort or randomised controlled studies that compared effects of weight-loss diets to standard care on postoperative outcomes in adults with obesity awaiting surgery. Participants with cancer or undergoing bariatric surgery were excluded. Data on preoperative weight change, length of stay, postoperative complications and patient-reported outcome measures were extracted and synthesised in meta-analyses. One randomised controlled trial involving total knee arthroplasty and two that investigated general surgery were eligible that included 173 participants overall. Each study compared low-calorie diets using meal replacement formulas to usual care. There is very-low-quality evidence of a statistically significant difference favouring the intervention for preoperative weight loss (mean difference [MD] -6.67 kg, 95% confidence interval [CI] -12.09 to -1.26 kg; p = 0.02) and low-quality evidence that preoperative weight-loss diets do not reduce postoperative complications to 30 days (odds ratio [OR] 0.34, 95% CI 0.08-1.42; p = 0.14) or length of stay (MD -3.72 h, 95% CI -10.76 to 3.32; p = 0.30). From the limited data that is of low quality, weight loss diets before elective surgery do not reduce postoperative complications.

The Changing Characteristics of Arthroplasty Patients: A Retrospective Cohort Study

BACKGROUND

Total joint arthroplasty (TJA) is among the most common operations performed worldwide, with global volumes on the rise. It is important to understand if the characteristics of this patient population are changing over time for resource allocation and surgical planning. The purpose of this study is to examine how this patient population has changed between 2003 and 2017.

METHODS

A retrospective review of a prospective TJA database was conducted. Age, gender, body mass index, comorbidities, American Society of Anesthesiologists class, responsible diagnoses, and comorbidities were compared over 5-year intervals between 2003 and 2017. All patients undergoing primary, elective TJA were included.

RESULTS

Overall, 17,138 TJAs were included. Mean body mass index increased over the study period for total hip arthroplasty (THA; 29.4-30.4 kg/m², P < .0001) and total knee arthroplasty (TKA; 32.0-3.1 kg/m², P < .0001) patients. THA patients were significantly younger in more recent years (68.0-66.8 years old, P = .0026); this trend was not observed among TKA patients. Over the study period, a significantly higher proportion of patients were American Society of Anesthesiologists class III/IV for THA (50.5%-72.3%) and TKA (57.5%-80.7%) (P < .00001). Prevalence of common comorbidities did not change significantly.

CONCLUSION

The key findings of this retrospective analysis of a large prospective database are that patients undergoing TJA are becoming younger and more obese. It is unclear whether patients are becoming more medically complex. These trends paint a concerning picture of a population that is increasingly complex, and may require a greater allocation of resources in the future.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Hospital Frailty Risk Score Outperforms Current Risk Stratification Models in Primary Total Hip and Knee Arthroplasty

BACKGROUND

Models for risk stratification and prediction of outcome, such as the Charlson Comorbidity Index (CCI), the Elixhauser Comorbidity Method (ECM), the 5-factor modified Frailty Index (mFI-5), and the Hospital Frailty Risk Score (HFRS) have been validated in orthopedic surgery. The aim of this study is to compare the predictive power of these models in total hip and knee replacement.

METHODS

In a retrospective analysis of 8250 patients who had undergone total joint replacement between 2011 and 2019, CCI, ECM, mFI-5, and HFRS were calculated for each patient. Receiver operating characteristic curve plots were generated and the area under the curve (AUC) was compared between each score with regard to adverse events such as transfusion, surgical, medical, and other complications. Multivariate logistic regression models were used to assess the relationship among risk stratification models, demographic factors, and postoperative adverse events.

RESULTS

In prediction of surgical complications, HFRS performed best (AUC: 0.719, P < .001), followed by ECM (AUC: 0.578, P < .001), mFI-5 (AUC: 0.564, P = .003), and CCI (AUC: 0.555, P = .012). With regard to medical complications, other complications, and transfusion, HFRS also was superior to ECM, mFI-5, and CCI. Multivariate logistic regression analyses revealed HFRS as an independent risk stratification model associated with all captured adverse events (P ≤ .001).

CONCLUSION

The HFRS is superior to current risk stratification models in the context of total joint replacement. As the HRFS derives from routinely collected administrative data, healthcare providers can identify at-risk patients without additional effort or expense.

Safety and Tolerability of Fluoroquinolones in Patients with Staphylococcal Periprosthetic Joint Infections

BACKGROUND

Fluoroquinolones (FQs) are known to be accompanied by significant risks. However, the incidence of adverse events (ADE) resulting in unplanned drug discontinuation when used for periprosthetic joint infections (PJI) is currently unknown.

METHODS

This study included 156 patients over the age of 18 treated for staphylococcal PJI with debridement, antibiotics, and implant retention (DAIR), between January 1, 2007 and November 21, 2019. Of the 156 patients, 64 had total hip arthroplasty (THA) and 92 had total knee arthroplasty (TKA) infections. The primary outcome was rate of unplanned drug discontinuation. Secondary outcomes included incidence of severe ADE, unplanned rifamycin discontinuation, mean time to unplanned regimen discontinuation, and all-cause mortality.

RESULTS

Overall, unplanned drug discontinuation occurred in 35.6% of patients in the FQ group and 3% of patients in the non-FQ group. The rate of unplanned discontinuation of FQ regimens as compared to non-FQ regimens was 27.5% vs 4.2% (p=0.021) in THA infections and 42% vs 2.4% (p<0.001) in TKA infections. There was no significant difference in severe ADEs between FQ and non-FQ regimens in both THA and TKA infections. The overall rate of non-severe ADEs in FQ compared to non-FQ regimens was 43.3% vs 6.1% (p<0.001). FQs were associated with tendinopathy, myalgia, arthralgia, and nausea.

CONCLUSIONS

A significantly higher rate of unplanned drug discontinuation was associated with FQ as compared to non-FQ regimens. This provides a real-world view of the implications of FQ related adverse events on unplanned discontinuation when used in prolonged durations for the management of staphylococcal PJIs.

Demographic, Comorbidity, and Episode-of-Care Differences in Primary Total Knee Arthroplasty

BACKGROUND

Understanding time trends in age, demographic characteristics, and comorbidities is especially critical to highlight the effects on clinical practice change, outcomes, and the value of total knee arthroplasty (TKA). Therefore, the purpose of this study was to identify trends in the demographic characteristics, comorbidities, and episode-of-care outcomes for patients who underwent TKA from 2008 to 2018.

METHODS

The National Surgical Quality Improvement Program (NSQIP) was queried to identify patient demographic characteristics, comorbidities, and episode-of-care outcomes in patients who underwent primary TKA from 2008 to 2018 (n = 350,879). Trends for continuous variables were analyzed using analysis of variance, and categorical variables were analyzed using chi-square tests.

RESULTS

From 2008 to 2018, there was no clinically important difference in age, body mass index (BMI), and percentage of patients with BMI of >40 kg/m2 and no clinically important difference in chronic obstructive pulmonary disease (3.5% in 2008 and 3.2% in 2018), congestive heart failure within 30 days (0.3% in both 2008 and 2018), and acute renal failure (0.1% in 2008 and <0.1% in 2018) among patients undergoing TKA. However, modifiable comorbidities, including smoking status (9.5% in 2008 and 7.7% in 2018; p < 0.001), hypertension (71.0% in 2008 and 63.7% in 2018; p < 0.001), and anemia (16.2% in 2008 and 9.7% in 2018; p < 0.001), functional status, and overall morbidity and mortality probability have improved, with no clinically important difference in the percentage of diabetes (19.0% in 2008 and 18.1% in 2018). The hospital length of stay (mean [and standard deviation], 3.8 ± 2.2 days in 2008 and 2.1 ± 2.0 days in 2018; p < 0.001) and 30-day readmission (4.6% in 2011 and 3.0% in 2018; p < 0.001) decreased, with a significant increase in home discharge (65.6% in 2011 and 87.8% in 2018; p < 0.001).

CONCLUSIONS

The overall patient health status improved from 2008 to 2018, with improvement in the modifiable comorbidities of smoking status, malnutrition, hypertension, and anemia; the functional status; and the overall morbidity and mortality probability, with no clinically relevant change in patient age; patient BMI; percentage of patients with BMI of >40 kg/m2; or patients with diabetes mellitus, chronic obstructive pulmonary disease, congestive heart failure within 30 days, or acute renal failure. Our findings may be a reflection of a global shift toward value-based care focusing on patient optimization prior to arthroplasty, quality of care, and improved outcomes. The results of our study highlight the potential increase in TKA procedural value, which is paramount for health-care policy changes in today's incentivized, value-based, health-care environment.

Customised, individually made total knee arthroplasty shows promising 1-year clinical and patient reported outcomes

INTRODUCTION

Customised individually made (CIM) implants for total knee arthroplasty (TKA) were introduced about 10 years ago. These implants aim to reduce the risk of prosthesis-related issues resulting from anthropometric differences between different knees. The purpose of this study was to analyse the short-term clinical outcome and patient reported outcome measures (PROMs) of a specific CIM implant, the ORIGIN^® knee replacement system (Symbios, Yverdon-les-Bains, Switzerland), which was introduced in 2018.

MATERIALS AND METHODS

This is a prospective cohort study of patients undergoing primary posterior-stabilised (PS) CIM TKA using the specific ORIGIN^® knee replacement system, (Symbios, Yverdon-les-Bains, Switzerland). TKAs were performed from February 2019 to October 2020. Data was collected preoperatively and postoperatively at 4 and 12 months. Outcome measures included the objective part of the Knee Society Score (KSS) with the range of motion (ROM) and the following PROMs: the Knee injury and Osteoarthritis Outcome Score (KOOS), the Forgotten Joint Score (FJS-12), the EuroQol, five dimensions, three levels (EQ-5D-3L) with the EuroQol visual analogue scale (EQ-VAS) and patient satisfaction. Differences in pre- to preoperative data were assessed with paired sample t tests. A p value < 0.05 was considered significant.

RESULTS

Twenty-five CIM TKA (20 patients, 8 female) were included. The mean age at surgery was 66 years (SD, 6.9). At 4 and 12 months, significant improvements in the KSS (p < 0.001), the ROM (p < 0.001), all KOOS subscales (p < 0.001), the FJS (p < 0.001) and the EQ-5D-3L (p < 0.026) were found. Satisfaction rate was 91% and 88% at 4 and 12 months, respectively. Intraoperative complications did not occur and no revision surgeries were undertaken.

CONCLUSIONS

The present study demonstrated significant improvements in the KSS and specific PROMs 1 year after CIM TKA. This study suggests that CIM TKA is a safe and suitable option, which can yield good clinical outcome and PROMs at least during short-term follow-up.

Hospital Frailty Risk Score Predicts Adverse Events in Primary Total Hip and Knee Arthroplasty

BACKGROUND

The Hospital Frailty Risk Score (HFRS) is a validated geriatric comorbidity measure derived from routinely collected administrative data. The purpose of this study is to evaluate the utility of the HFRS as a predictor for postoperative adverse events after primary total hip (THA) and knee (TKA) arthroplasty.

METHODS

In a retrospective analysis of 8250 patients who had undergone THA or TKA between 2011 and 2019, the HFRS was calculated for each patient. Reoperation rates, readmission rates, complication rates, and transfusion rates were compared between patients with low and intermediate or high frailty risk. Multivariate logistic regression models were used to assess the relationship between the HFRS and postoperative adverse events.

RESULTS

Patients with intermediate or high frailty risk showed a higher rate of reoperation (10.6% vs 4.1%, P < .001), readmission (9.6% vs 4.3%, P < .001), surgical complications (9.1% vs 1.8%, P < .001), internal complications (7.3% vs 1.1%, P < .001), other complications (24.4% vs 2.0%, P < .001), Clavien-Dindo grade IV complications (4.1% vs 1.5%, P < .001), and transfusion (10.4% vs 1.3%, P < .001). Multivariate logistic regression analyses revealed a high HFRS as independent risk factor for reoperation (odds ratio [OR] = 2.1; 95% confidence interval [CI], 1.46-3.09; P < .001), readmission (OR = 1.78; 95% CI, 1.21-2.61; P = .003), internal complications (OR = 3.72; 95% CI, 2.28-6.08; P < .001), surgical complications (OR = 3.74; 95% CI, 2.41-5.82; P < .001), and other complications (OR = 9.00; 95% CI, 6.58-12.32; P < .001).

CONCLUSION

The HFRS predicts adverse events after THA and TKA. As it derives from routinely collected data, the HFRS enables hospitals to identify at-risk patients without extra effort or expense.

LEVEL OF EVIDENCE

Level III-retrospective cohort study.

Sex-Modified Effects of Depression, Low Back Pain, and Comorbidities on Pain After Total Knee Arthroplasty for Osteoarthritis

OBJECTIVE

The influence of sex on post-total knee arthroplasty (TKA) outcomes has been variable in the literature. Though sex is often reported as an averaged effect, we undertook this study to investigate whether sex modified the influence of presurgery characteristics on post-TKA knee pain.

METHODS

This was a prospective study with data derived from 477 TKA osteoarthritis patients (279 women, 198 men). Questionnaires were completed presurgery and at 3 months postsurgery. The association between 3-month post-TKA knee pain and presurgery covariates (body mass index, comorbidity count, symptomatic joint count, low back pain, knee pain, and depressive symptoms) was assessed by linear regression. Sex-specific effects were evaluated using interactions.

RESULTS

Women had significantly worse presurgery knee pain, joint count, and depressive symptoms, and worse postsurgery knee pain, than men. With simple covariate adjustment, no sex effect on pain was found. However, sex was found to moderate the effects of comorbidities (worse for women [P = 0.013]), presence of low back pain (worse for men [P = 0.003]), and depressive symptoms (worse for men [P < 0.001]) on postsurgery pain. Worse presurgery pain was associated with worse postsurgery pain similarly for women and men.

CONCLUSION

The influence of some patient factors on early post-TKA pain cannot be assumed to be the same for women and men; average effects may mask underlying associations. Results suggest a need to consider sex differences in understanding TKA outcomes, which may have important implications for prognostic tool development in TKA.

Osteochondritis Dissecans in the Knee of Skeletally Immature Patients: Rates of Persistent Pain, Osteoarthritis, and Arthroplasty at Mean 14-Years' Follow-Up

OBJECTIVE

Osteochondritis dissecans (OCD) is a knee disorder of predominately pediatric populations. Because of low incidence, it has traditionally been difficult to study OCD. The purpose of this study was to report long-term outcomes of skeletally immature OCD lesions and determine risk factors for persistent knee pain at final follow-up.

DESIGN

A geographic database of more than 500,000 patients was reviewed to identify patients with knee OCD. Clinical course including operative management, persistent knee pain, and total knee arthroplasty (TKA) were analyzed through review of radiographs, magnetic resonance images, and physician notes.

RESULTS

A total of 95 skeletally immature patients (70 male, 25 female, mean age 12.5 ± 2.0 years) were followed for a mean of 14 years (range, 2-40 years). Fifty-three patients were treated operatively and 42 were treated nonoperatively. At final follow-up, 13 patients noted persistent knee pain, 8 treated operatively versus 5 treated nonoperatively. Risk factors for knee pain were female gender, patellar lesions, and unstable lesions. Four patients (8%) treated operatively and 2 patients (5%) treated nonoperatively developed symptomatic osteoarthritis at a mean of 28.6 years following diagnosis. Three patients underwent TKA at a mean age of 52 years, significantly younger than that observed for primary TKA at our institution (P = 0.004).

CONCLUSIONS

Skeletally immature OCD patients have promising histories, with an estimated 14% risk of persistent knee pain, 6% symptomatic osteoarthritis, and 3% conversion to TKA at 14 years' mean follow-up. Females, patellar lesions, and unstable lesions demonstrated increased persistent knee pain risk. Patients with OCD undergo TKA at a significantly younger age than the general population.

Autologous Biologic Treatment with Fat, Bone Marrow Aspirate and Platelet Rich Plasma Is an Effective Alternative to Total Knee Arthroplasty for Patients with Moderate Knee Arthrosis

Background: Osteoarthrosis (OA) of the knee afflicts millions worldwide. Total Knee Arthroplasty (TKA) is common, but associated with substantial cost and morbidity. Prior studies of intra-articular injection of fat, bone marrow aspirate (BMA), and platelet rich plasma (PRP) have shown clinical benefit. We hypothesized that injection of autologous adipose tissue, BMA, and PRP would provide significant benefit for patients with moderate knee OA resulting in avoidance of total knee arthroplasty (TKA) in most, with discontinuance of NSAIDs and other drugs. Methods: 42 TKA candidate patients (47 knees) with moderate (Kellgren-Lawrence 2 and 3) knee OA who had failed conservative treatment had autologous adipose tissue, BMA, and PRP injection as an alternative to TKA in office using only local anesthetic. Patients had discontinuance of all nonsteroidal anti-inflammatory medicines (NSAIDs) and other analgesics, except acetaminophen, prior to treatment. Patients were evaluated with Knee injury and Osteoarthritis Outcome Score Physical Shortform (KOOS-PS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Single Assessment Numeric Evaluation (SANE) prior to treatment, and at 6 months, 1, and 2 years after treatment. Results: Follow up exceeded 80% at all time points. There were no significant adverse events. TKA was avoided in 97% at one and 86% at two years after treatment. Mean SANE, KOOS-PS, and WOMAC scores significantly improved at 6 months, 1, and 2 years post-treatment. WOMAC and SANE scores were higher at two versus one year post-treatment. Conclusions: Combined fat, BMA, and PRP injection is a safe and effective treatment for moderate knee OA, with reliable avoidance of TKA and possible continued improvement at two year follow-up.

Varus-valgus constraint in 416 revision total knee arthroplasties with cemented stems provides a reliable reconstruction with a low subsequent revision rate at early to mid-term review

AIMS

Varus-valgus constrained (VVC) implants are often used during revision total knee arthroplasty (TKA) to gain coronal plane stability. However, the increased mechanical torque applied to the bone-cement interface theoretically increases the risk of aseptic loosening. We assessed mid-term survivorship, complications, and clinical outcomes of a fixed-bearing VVC device in revision TKAs.

METHODS

A total of 416 consecutive revision TKAs (398 patients) were performed at our institution using a single fixed-bearing VVC TKA from 2007 to 2015. Mean age was 64 years (33 to 88) with 50% male (199). Index revision TKA diagnoses were: instability (n = 122, 29%), aseptic loosening (n = 105, 25%), and prosthetic joint infection (PJI) (n = 97, 23%). All devices were cemented on the epiphyseal surfaces. Femoral stems were used in 97% (n = 402) of cases, tibial stems in 95% (n = 394) of cases; all were cemented. In total, 93% (n = 389) of cases required a stemmed femoral and tibial component. Femoral cones were used in 29%, and tibial cones in 40%. Survivorship was assessed via competing risk analysis; clinical outcomes were determined using Knee Society Scores (KSSs) and range of movement (ROM). Mean follow-up was four years (2 to 10).

RESULTS

The five-year cumulative incidence of subsequent revision for aseptic loosening and instability were 2% (95% confidence interval (CI) 0.2 to 3, number at risk = 154) and 4% (95% CI 2 to 6, number at risk = 153), respectively. The five-year cumulative incidence of any subsequent revision was 14% (95% CI 10 to 18, number at risk = 150). Reasons for subsequent revision included PJI (n = 23, of whom 12 had previous PJI), instability (n = 13), and aseptic loosening (n = 11). The use of this implant without stems was found to be a significant risk factor for subsequent revision (hazard ratio (HR) 7.58 (95% CI 3.98 to 16.03); p = 0.007). KSS improved from 46 preoperatively to 81 at latest follow-up (p < 0.001). ROM improved from 96° prerevision to 108° at latest follow-up (p = 0.016).

CONCLUSION

The cumulative incidence of subsequent revision for aseptic loosening and instability was very low at five years with this fixed-bearing VVC implant in revision TKAs. Routine use of cemented and stemmed components with targeted use of metaphyseal cones likely contributed to this low rate of aseptic loosening. Cite this article: Bone Joint J 2020;102-B(4):458-462.

Patients' perspectives of outcomes after total knee and total hip arthroplasty: a nominal group study

Background

While total joint replacements (TJR) are frequently performed, there is little qualitative research to define the outcomes most important to patients.

Methods

Patients who had received total hip (THR) or total knee replacements (TKR) participated in 8 nominal groups to answer the question "What result/results matter the most to a patient undergoing/having a knee or hip replacement?" Total 270 votes were allocated.

Results

Eight nominal groups were performed with 45 patients, 6 groups with mean age (71.1 ± 9.3), and 2 with 9 younger patients (mean age 36.8 ± 7.4). All had TJR between 2016 and 2018; overall, 40% were male, 15.6% were Black, and 75% were performed for osteoarthritis. While all groups ranked the same top 3 outcomes, responses varied with age: 1) relief of pain (46% vs. 35% in the young groups); 2) improved function including mobility (29% vs. 18% in the young groups); 3) restored quality of life (13% vs 33% of votes in the younger group).

Conclusion

Relief of pain and restoration of function, and improved quality of life are the 3 outcomes ranked highest by patients, confirming their inclusion in TJR clinical trials.

Declining early mortality after hip and knee arthroplasty

BACKGROUND

We aimed to measure the period effect (change over time) in 30-day mortality after total hip arthroplasty (THA) and total knee arthroplasty (TKA) using data from the Australian Orthopaedic Association National Joint Replacement Registry.

METHODS

We performed an observational study using national registry data from all hospitals performing THA and TKA in Australia including people undergoing primary elective conventional THA and TKA for osteoarthritis from 2003 to 2017, inclusive. Data from the Australian Orthopaedic Association National Joint Replacement Registry, the National Death Index and the Australian Bureau of Statistics were used to generate unadjusted 30-day mortality, the incident rate ratio for mortality adjusted for age and gender, and the standardized mortality ratio at 30 days for each year separately.

RESULTS

For the years 2003 and 2017, respectively, for THA, the unadjusted 30-day mortality was 0.23% and 0.06%, and the standardized mortality ratio was 1.11 (95% CI: 0.73, 1.49) and 0.38 (95% CI: 0.16, 0.59). The incident rate ratio was significantly higher than the reference year (2017) from 2003 to 2010, and for 2012, 2013 and 2016, decreasing over time. For the years 2003 and 2017, respectively, for TKA, the unadjusted 30-day mortality was 0.17% and 0.08%, and the standardized mortality ratio was 0.84 (95% CI: 0.55, 1.13) and 0.61 (95% CI: 0.38, 0.83). The incident rate ratio was significantly higher than the reference year (2017) from 2003 to 2009 inclusive, decreasing over time.

CONCLUSIONS

Thirty-day mortality after THA and TKA declined from 2003 to 2017. This may be due to improvements in intra-operative and post-operative patient management.

Acquired Idiopathic Stiffness After Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

Stiffness is a common reason for suboptimal clinical outcomes after primary total knee arthroplasty (pTKA). There is a lack of consensus regarding its definition, which is often conflated with its histopathologic subcategory-i.e., arthrofibrosis. There is value in refining the definition of acquired idiopathic stiffness in an effort to select for patients with arthrofibrosis. We conducted a systematic review and meta-analysis to establish a consensus definition of acquired idiopathic stiffness, determine its prevalence after pTKA, and identify potential risk factors for its development.

METHODS

MEDLINE, Embase, Cochrane Controlled Register of Trials (CENTRAL), and Scopus databases were searched from 2002 to 2017. Studies that included patients with stiffness after pTKA were screened with strict inclusion and exclusion criteria to isolate the subset of patients with acquired idiopathic stiffness unrelated to known extrinsic or surgical causes. Three authors independently assessed study eligibility and risk of bias and collected data. Outcomes of interest were then analyzed according to age, sex, and body mass index (BMI).

RESULTS

In the 35 included studies (48,873 pTKAs), the mean patient age was 66 years. In 63% of the studies, stiffness was defined as a range of motion of <90° or a flexion contracture of >5° at 6 to 12 weeks postoperatively. The prevalence of acquired idiopathic stiffness after pTKA was 4%, and this did not differ according to age (4%, I = 95%, among patients <65 years old and 5%, I = 96%, among those ≥65 years old; p = 0.238). The prevalence of acquired idiopathic stiffness was significantly lower in males (1%, I = 85%) than females (3%, I = 95%) (p < 0.0001) as well as in patients with a BMI of <30 kg/m (2%, I = 94%) compared with those with a BMI of ≥30 kg/m (5%, I = 97%) (p = 0.027).

CONCLUSIONS

Contemporary literature supports the following definition for acquired idiopathic stiffness: a range of motion of <90° persisting for >12 weeks after pTKA in patients in the absence of complicating factors including preexisting stiffness. The mean prevalence of acquired idiopathic stiffness after pTKA was 4%; females and obese patients were at increased risk.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Predicting Inpatient Status After Primary Total Knee Arthroplasty in Medicare-Aged Patients

BACKGROUND

The Centers for Medicare and Medicaid Services (CMS) removed total knee arthroplasty (TKA) from its inpatient only (IPO) list as of January 1, 2018. The purpose of this study was to establish a risk-stratifying nomogram to aid in determining the need for inpatient admission among Medicare-aged patients undergoing primary TKA.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried to identify all patients aged ≥65 years who underwent primary TKA between 2006 and 2015. The primary outcome measure was inpatient admission, as defined by hospital length of stay longer than 2 days. Multiple demographic, comorbid, and perioperative variables were incorporated in a multivariate logistic regression model to yield a risk stratification nomogram.

RESULTS

Sixty-one thousand two hundred eighty-four inpatient and 26,066 outpatient admissions were analyzed. Age >80 years (odds ratio [OR] = 2.27, P < .0001, 95% confidence interval [CI] = 2.13-2.42), simultaneous bilateral TKA (OR = 2.02, P < .0001, 95% CI = 1.77-2.30), dependent functional status (OR = 1.95, P < .0001, 95% CI = 1.62-2.35), metastatic cancer (OR = 1.91, P = .055, 95% CI = 0.99-3.73), and female gender (OR = 1.76, P < .0001, 95% CI = 1.70-1.82) were the greatest determinants of inpatient stay. The resulting predictive model demonstrated acceptable discrimination and excellent calibration.

CONCLUSION

Our model enabled a reliable and straightforward identification of the most suitable candidates for inpatient admission in Medicare aged-patients undergoing primary TKA. Larger multicenter studies are necessary to externally validate the proposed predictive nomogram.

A Novel Mobile Phone Text Messaging Platform Improves Collection of Patient-Reported Post-operative Pain and Opioid Use Following Orthopedic Surgery

BACKGROUND

Prospective collection of patient-reported opioid consumption and pain levels post-surgically may hold value in highlighting solutions related to the opioid crisis. Traditional methods for collecting patient-reported outcomes after surgery, such as paper surveys, often have poor response rates, and electronic messaging may offer more convenience and therefore yield more robust data.

QUESTIONS/PURPOSES

The purpose of this study was to evaluate whether a novel mobile phone short message service (SMS) platform would lead to better patient response rates to surveys on pain and opioid use than data-collection tools.

METHODS

An SMS text messaging platform was created and implemented between September 2017 and May 2018 at an orthopedic specialty hospital. The purpose was to collect reports on opioid consumption and pain levels twice a day for 6 weeks post-surgery from patients who had undergone total hip or knee arthroplasty or a single-level lumbar microdiscectomy or decompression spine surgery. Patients who responded to fewer than 50% of the text messages were excluded.

RESULTS

Our mobile phone text messaging platform was used by 183 patients, demonstrating a significantly higher response rate (96.1%) than our institution's post-operative email registry capture, as well as the majority of published response rates for post-operative outcomes captured through electronic and traditional data-collection systems. Response rate remained consistently high among the various surgeons and across patients, regardless of age.

CONCLUSIONS

This application of a widely available technology can improve the measurement of post-operative patient-reported outcomes. Such data can in turn be used in the development of strategies to reduce post-operative opioid use. The adoption of novel technologies at a patient level will play a key role in combating the opioid epidemic.

Extended Oral Antibiotic Prophylaxis in High-Risk Patients Substantially Reduces Primary Total Hip and Knee Arthroplasty 90-Day Infection Rate

BACKGROUND

Total joint arthroplasty (TJA) episodic payment models shift risk and cost of periprosthetic joint infection (PJI) to surgeons and hospitals, causing some to avoid treating high-risk patients. Furthermore, there are little data to support optimization of host factors preoperatively to decrease PJI, and recent literature supports using extended antibiotic prophylaxis following reimplantation TJA. The purpose of this study was to evaluate whether extended oral antibiotic prophylaxis minimized PJI after primary TJA in high-risk patients.

METHODS

A retrospective cohort study was performed of 2,181 primary total knee arthroplasties (TKAs) and primary total hip arthroplasties (THAs) carried out from 2011 through 2016 at a suburban academic hospital with modern perioperative and infection-prevention protocols. Beginning in January 2015, extended oral antibiotic prophylaxis for 7 days after discharge was implemented for patients at high risk for PJI. The percentages of patients diagnosed with PJI within 90 days were identified and compared between groups that did and did not receive extended oral antibiotic prophylaxis, with p ≤ 0.05 indicating significance.

RESULTS

The 90-day infection rates were 1.0% and 2.2% after the TKAs and THAs, respectively. High-risk patients without extended antibiotic prophylaxis were 4.9 (p = 0.009) and 4.0 (p = 0.037) times more likely to develop PJI after TKA and THA, respectively, than high-risk patients with extended antibiotic prophylaxis.

CONCLUSIONS

Extended postoperative antibiotic prophylaxis led to a statistically significant and clinically meaningful reduction in the 90-day infection rate of selected patients at high risk for infection. We encourage further study and deliberation prior to adoption of a protocol involving extended oral antibiotic prophylaxis after high-risk TJA, with the benefits weighed appropriately against potential adverse consequences such as increasing the development of antimicrobial resistance.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The Metabolome and Osteoarthritis: Possible Contributions to Symptoms and Pathology

Osteoarthritis (OA) is a progressive, deteriorative disease of articular joints. Although traditionally viewed as a local pathology, biomarker exploration has shown that systemic changes can be observed. These include changes to cytokines, microRNAs, and more recently, metabolites. The metabolome is the set of metabolites within a biological sample and includes circulating amino acids, lipids, and sugar moieties. Recent studies suggest that metabolites in the synovial fluid and blood could be used as biomarkers for OA incidence, prognosis, and response to therapy. However, based on clinical, demographic, and anthropometric factors, the local synovial joint and circulating metabolomes may be patient specific, with select subsets of metabolites contributing to OA disease. This review explores the contribution of the local and systemic metabolite changes to OA, and their potential impact on OA symptoms and disease pathogenesis.

Effects of anaesthesia and analgesia on long-term outcome after total knee replacement: A prospective, observational, multicentre study

BACKGROUND

Perioperative regional anaesthesia may protect from persistent postsurgical pain (PPSP) and improve outcome after total knee arthroplasty (TKA).

OBJECTIVES

Aim of this study was to evaluate the impact of regional anaesthesia on PPSP and long-term functional outcome after TKA.

DESIGN

A web-based prospective observational registry.

SETTING

Five Italian Private and University Hospitals from 2012 to 2015.

PATIENTS

Undergoing primary unilateral TKA, aged more than 18 years, informed consent, American Society of Anesthesiologists (ASA) physical status classes 1 to 3, no previous knee surgery.

INTERVENTION(S)

Personal data (age, sex, BMI and ASA class), preoperative pain assessed by numerical rating scale (NRS) score, and risk factors for PPSP were registered preoperatively. Data on anaesthetic and analgesic techniques were collected. Postoperative pain (NRS), analgesic consumption, major complications and patient satisfaction were registered up to the time of discharge. PPSP was assessed by a blinded investigator during a phone call after 1, 3 and 6 months, together with patient satisfaction, quality of life (QOL) and walking ability.

MAIN OUTCOME MEASURES

Experience of PPSP according to the type of peri-operative analgesia.

RESULTS

Five hundred sixty-three patients completed the follow-up. At 6 months, 21.6% of patients experienced PPSP, whereas autonomy was improved only in 56.3%; QOL was worsened or unchanged in 30.7% of patients and improved in 69.3%. Patients receiving continuous regional anaesthesia (epidural or peripheral nerve block) showed a lower NRS through the whole peri-operative period up to 1 month compared with both single shot peripheral nerve block and those who did not receive any type of regional anaesthesia. No difference was found between these latter two groups. Differences in PPSP at 3 or 6 months were not significantly affected by the type of anaesthesia or postoperative analgesia. A higher NRS score at 1 month, younger age, history of anxiety or depression, pro-inflammatory status, higher BMI and a lower ASA physical status were associated with a higher incidence of PPSP and worsened QOL at 6 months.

CONCLUSION

Continuous regional anaesthesia provides analgesic benefit for up to 1 month after surgery, but did not influence PPSP at 6 months. Better pain control at 1 month was associated with reduced PPSP. Patients with higher expectations from surgery, enhanced basal inflammation and a pessimistic outlook are more prone to develop PPSP.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02147730.

Effects of anaesthesia and analgesia on long-term outcome after total knee replacement: A prospective, observational, multicentre study

BACKGROUND

Perioperative regional anaesthesia may protect from persistent postsurgical pain (PPSP) and improve outcome after total knee arthroplasty (TKA).

OBJECTIVES

Aim of this study was to evaluate the impact of regional anaesthesia on PPSP and long-term functional outcome after TKA.

DESIGN

A web-based prospective observational registry.

SETTING

Five Italian Private and University Hospitals from 2012 to 2015.

PATIENTS

Undergoing primary unilateral TKA, aged more than 18 years, informed consent, American Society of Anesthesiologists (ASA) physical status classes 1 to 3, no previous knee surgery.

INTERVENTION(S)

Personal data (age, sex, BMI and ASA class), preoperative pain assessed by numerical rating scale (NRS) score, and risk factors for PPSP were registered preoperatively. Data on anaesthetic and analgesic techniques were collected. Postoperative pain (NRS), analgesic consumption, major complications and patient satisfaction were registered up to the time of discharge. PPSP was assessed by a blinded investigator during a phone call after 1, 3 and 6 months, together with patient satisfaction, quality of life (QOL) and walking ability.

MAIN OUTCOME MEASURES

Experience of PPSP according to the type of peri-operative analgesia.

RESULTS

Five hundred sixty-three patients completed the follow-up. At 6 months, 21.6% of patients experienced PPSP, whereas autonomy was improved only in 56.3%; QOL was worsened or unchanged in 30.7% of patients and improved in 69.3%. Patients receiving continuous regional anaesthesia (epidural or peripheral nerve block) showed a lower NRS through the whole peri-operative period up to 1 month compared with both single shot peripheral nerve block and those who did not receive any type of regional anaesthesia. No difference was found between these latter two groups. Differences in PPSP at 3 or 6 months were not significantly affected by the type of anaesthesia or postoperative analgesia. A higher NRS score at 1 month, younger age, history of anxiety or depression, pro-inflammatory status, higher BMI and a lower ASA physical status were associated with a higher incidence of PPSP and worsened QOL at 6 months.

CONCLUSION

Continuous regional anaesthesia provides analgesic benefit for up to 1 month after surgery, but did not influence PPSP at 6 months. Better pain control at 1 month was associated with reduced PPSP. Patients with higher expectations from surgery, enhanced basal inflammation and a pessimistic outlook are more prone to develop PPSP.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02147730

Time Trends in Characteristics of Patients Undergoing Primary Total Hip and Knee Arthroplasty in California, 2007-2010

BACKGROUND

As the number of total hip and knee arthroplasty cases increases, it is important to understand the burden of factors that impact patient outcomes of these procedures. This article examined the time trends in key demographics, clinical characteristics, comorbidity burden (Deyo-Charlson Comorbidity Index [CCI]), and presence of depression in patients undergoing primary total hip arthroplasty and total knee arthroplasty using population-based, all-payer inpatient database, California Healthcare Cost and Utilization Project, from 2007 to 2010.

METHODS

Chi-square tests and analysis of variance were used. Multivariate logistic regression analyses were also performed to compare the prevalence of depression in 2007 to later years.

RESULTS

In the primary total hip arthroplasty cohort, the prevalence of depression significantly increased by 20%, mean age decreased by 0.4 years, mean length of stay (LOS) decreased by 0.5 days, and having a CCI score of ≥3 increased by 30% (P value < .001 for all) over the study period. Similarly, in the primary total knee arthroplasty cohort, the prevalence of depression increased by 23%, the mean age decreased by 0.4 years, mean LOS decreased by 0.4 days, and the prevalence of CCI score of ≥3 increased by 35% (P value < .001 for all).

CONCLUSION

Despite the younger age of the joint arthroplasty population over time, we found increased prevalence of depression and comorbidity scores but shorter LOS. Further study is needed to determine the impact of the changing demographics of the total joint population and the best strategies to optimize their outcome with these procedures.

A classification modeling approach for determining metabolite signatures in osteoarthritis

Multiple factors can help predict knee osteoarthritis (OA) patients from healthy individuals, including age, sex, and BMI, and possibly metabolite levels. Using plasma from individuals with primary OA undergoing total knee replacement and healthy volunteers, we measured lysophosphatidylcholine (lysoPC) and phosphatidylcholine (PC) analogues by metabolomics. Populations were stratified on demographic factors and lysoPC and PC analogue signatures were determined by univariate receiver-operator curve (AUC) analysis. Using signatures, multivariate classification modeling was performed using various algorithms to select the most consistent method as measured by AUC differences between resampled training and test sets. Lists of metabolites indicative of OA [AUC > 0.5] were identified for each stratum. The signature from males age > 50 years old encompassed the majority of identified metabolites, suggesting lysoPCs and PCs are dominant indicators of OA in older males. Principal component regression with logistic regression was the most consistent multivariate classification algorithm tested. Using this algorithm, classification of older males had fair power to classify OA patients from healthy individuals. Thus, individual levels of lysoPC and PC analogues may be indicative of individuals with OA in older populations, particularly males. Our metabolite signature modeling method is likely to increase classification power in validation cohorts.

A systematic review of psychological interventions in total hip and knee arthroplasty

BACKGROUND

The current practice in elective orthopaedics does not routinely include psychological interventions despite evidence that psychological factors such as personality, anxiety, depression and negative thinking styles can influence outcomes and recovery from surgery. The objective of this paper was to review the effectiveness of psychological interventions used in conjunction with total hip (THA) and knee arthroplasty (TKA), in improving patient reported joint outcomes.

METHODS

An extensive literature search was conducted according to Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. Search terms included psychology, interventions, and orthopaedics. Articles were included if they were randomised controlled trials (RCTs) of psychological interventions involving active patient participation measured with patient reported joint outcomes in patients undergoing hip or knee arthroplasty.

RESULTS

A total of 19,489 titles were screened. Seven studies met the inclusion criteria and were included. Five of seven studies did not show improvements in patient reported outcomes after surgery. Specifically, psycho-education alone was not effective at improving patient reported joint outcomes in two out of two studies.

CONCLUSION

The current literature does not support routine psychological interventions for TKA and THA. However, it should be noted that the literature for psychological interventions in conjunction with TKA and THA is still in its infancy. This gap in the literature is surprising, considering the importance of the role of psychological factors in recovery. Further RCTs with long term follow ups, multidisciplinary involvement, and more comprehensive and focused interventions that go beyond educating patients are needed. Future studies should account for the demand effect, include measures of psychological variables to determine whether psychological interventions are more beneficial for some patients compared to others, and compare the different modes of delivery and timing of interventions to determine the optimal nature and duration of psychological interventions for TKA and THA.

Does Education Level Mitigate the Effect of Poverty on Total Knee Arthroplasty Outcomes?

OBJECTIVE

Total knee arthroplasty (TKA) outcomes are worse for patients from poor neighborhoods, but whether education mitigates the effect of poverty is not known. We assessed the interaction between education and poverty on 2-year Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function.

METHODS

Patient-level variables from an institutional registry were linked to US Census Bureau data (census tract [CT] level). Statistical models including patient and CT-level variables were constructed within multilevel frameworks. Linear mixed-effects models with separate random intercepts for each CT were used to assess the interaction between education and poverty at the individual and community level on WOMAC scores.

RESULTS

Of 3,970 TKA patients, 2,438 (61%) had some college or more. Having no college was associated with worse pain and function at baseline and 2 years (P = 0.0001). Living in a poor neighborhood (>20% below poverty line) was associated with worse 2-year pain (P = 0.02) and function (P = 0.006). There was a strong interaction between individual education and community poverty with WOMAC scores at 2 years. Patients without college living in poor communities had pain scores that were ~10 points worse than those with some college (83.4% versus 75.7%; P < 0.0001); in wealthy communities, college was associated with a 1-point difference in pain. Function was similar.

CONCLUSION

In poor communities, those without college attain 2-year WOMAC scores that are 10 points worse than those with some college; education has no impact on TKA outcomes in wealthy communities. How education protects those in impoverished communities warrants further study.

Older Adults Undergoing Total Hip or Knee Arthroplasty: Chronicling Changes in Their Multimorbidity Profile in the Last Two Decades

BACKGROUND

Despite the ubiquitous use of total hip arthroplasty (THA) and total knee arthroplasty (TKA) in older adults, little is known about the multimorbidity (MM) profile of this patient population. This study evaluates the temporal trends of MM, hypothesizing that patients with MM have had an increasingly greater representation in THA and TKA patients over time.

METHODS

Data on a US representative sample of older adults from the linked Health and Retirement Study and Medicare data from 1993 to 2012 were used. The Health and Retirement Study is a biennial survey that collects data on a broad array of measures, including self-reported chronic conditions and geriatric syndromes, which were used to account for MM. Medicare data were used to identify fee-for-service Medicare beneficiaries who underwent THA (n = 479) or TKA (n = 998) during the study years, which were grouped into 3 periods: 1993-1999, 2000-2006, and 2007-2012. Multivariable logistic regression analysis was conducted to obtain age-, gender-, and race-adjusted time trends for MM.

RESULTS

Compared to the earliest study period, and for both THA and TKA patients, there were significantly fewer patients with stroke and/or poor cognitive performance in the most recent study period. In addition, more TKA than THA patients presented with 2+ chronic conditions. Nearly 70% presented with co-occurring chronic conditions and geriatric syndromes, and this percentage did not change significantly over time.

CONCLUSION

The high representation of THA and TKA patients presenting with co-occurring chronic conditions and geriatric syndromes in this patient population warrants detailed exploration of the effects of geriatric syndromes on postoperative outcomes.

Trends and Economic Impact of Hip and Knee Arthroplasty in Central Europe: Findings from the Austrian National Database

Arthroplasty registers were originally established in Scandinavia to receive clinically relevant information from pooled data, to improve quality and reduce revision surgeries, with socioeconomic benefit. In Austria, where the highest rate of total knee arthroplasties (TKA) per inhabitant of all OECD countries was reached in 2014, arthroplasties are centrally reported since 2009. Study purpose was to perform the first analysis of the Austrian database, aiming to obtain data on trends in arthroplasty in Austria over time in relation to demographic development. Between 2009 and 2015 an almost continuous increase of total hip arthroplasties (THA; 18.052) by 14% and TKA (17.324) by 13% were observed, representing 210 THA and 202 TKA per 100k inhabitants in 2015. A similar increase was found for revision surgeries, with 1.290 re-implanted THA (7.1% of all THA) and 919 re-implanted TKA (5.3% of all TKA) in 2015. Implantation of mega or tumor prosthesis for the knee and hip joint remained constant and was mainly performed in two university hospitals. Patellar resurfacing decreased by 31.6%. Demographic development will further increase the number of primary and revision surgeries. Inclusion of more detailed information on used and revised components was established and will improve efficacy in quality control.

Comparative analysis of quadriceps and hamstrings strength in knee osteoarthritis before and after total knee arthroplasty: a cross-sectional study

Objective

Compare the maximal isokinetic muscle strength of knee extensor and flexor muscles between patients with knee osteoarthritis and patients submitted to total knee arthroplasty.

Methods

Volunteers were divided into five groups (n = 20): Control; Ahlbäck I and II; Ahlbäck IV; six months after total knee arthroplasty; 12 months after total knee arthroplasty. An isokinetic knee strength evaluation was conducted for the quadriceps and hamstrings at 60°/s.

Results

Significant differences in the peak torque of the quadriceps and hamstrings were found among the groups (p < 0.001). The Ahlbäck IV, six-month, and 12-month postoperative groups demonstrated lower values when compared to the Control and Ahlbäck I and II groups. When percentage values were compared to the Control group, mean differences ranged from 7% to 41%.

Conclusion

Patients with healthy knees or early stage osteoarthritis have higher quadriceps and hamstrings strengths than those with a more advanced stage of the disease, even after knee replacement. These findings suggest that the traditional rehabilitation programs do not recover strength to levels observed in individuals without knee osteoarthritis.

Preoperative characteristics of working-age patients undergoing total knee arthroplasty

Objective

Total Knee Arthroplasty (TKA) is performed more in working-age (<65 years) patients. Until now, research in this patient population has been conducted mainly among retired (≥65 years) patients. Aim of this study was therefore to describe demographic, physical, psychological and social characteristics of working TKA patients and to subsequently compare these characteristics with retired TKA patients and the general population.

Methods

A cross-sectional analysis. Preoperative data of 152 working TKA patients was used. These data were compared with existing data of retired TKA patients in hospital registers and with normative values from literature on the general population. Demographic, physical, psychological and social (including work) characteristics were analyzed.

Results

The majority (83.8%) of working TKA patients was overweight (42.6%) or obese (41.2%), a majority (72.4%) was dealing with two or more comorbidities, and most (90%) had few depressive symptoms. Mean physical activity level was 2950 minutes per week. Compared to the retired TKA population, working TKA patients perceived significantly more stiffness and better physical functioning and vitality, were more physically active, and perceived better mental health. Compared to the general population working TKA patients perceived worse physical functioning, worse physical health and better mental health, and worked fewer hours.

Conclusion

This study shows that a majority of working TKA patients are overweight/obese, have multiple comorbidities, but are highly active in light-intensity activities and have few depressive symptoms. Working patients scored overall better on preoperative characteristics than retired patients, and except for physical activity scored overall worse than the general population.

Lower limb arthroplasty: can we produce a tool to predict outcome and failure, and is it cost-effective? An epidemiological study

Background

Although hip and knee arthroplasties are considered to be common elective cost-effective operations, up to one-quarter of patients are not satisfied with the operation. A number of risk factors for implant failure are known, but little is known about the predictors of patient-reported outcomes.

Objectives

(1) Describe current and future needs for lower limb arthroplasties in the UK; (2) describe important risk factors for poor surgery outcomes and combine them to produce predictive tools (for hip and knee separately) for poor outcomes; (3) produce a Markov model to enable a detailed health economic analysis of hip/knee arthroplasty, and for implementing the predictive tool; and (4) test the practicality of the prediction tools in a pragmatic prospective cohort of lower limb arthroplasty.

Design

The programme was arranged into four work packages. The first three work packages used the data from large existing data sets such as Clinical Practice Research Datalink, Hospital Episode Statistics and the National Joint Registry. Work package 4 established a pragmatic cohort of lower limb arthroplasty to test the practicality of the predictive tools developed within the programme.

Results

The estimated number of total knee replacements (TKRs) and total hip replacements (THRs) performed in the UK in 2015 was 85,019 and 72,418, respectively. Between 1991 and 2006, the estimated age-standardised rates (per 100,000 person-years) for a THR increased from 60.3 to 144.6 for women and from 35.8 to 88.6 for men. The rates for TKR increased from 42.5 to 138.7 for women and from 28.7 to 99.4 for men. The strongest predictors for poor outcomes were preoperative pain/function scores, deprivation, age, mental health score and radiographic variable pattern of joint space narrowing. We found a weak association between body mass index (BMI) and outcomes; however, increased BMI did increase the risk of revision surgery (a 5-kg/m2rise in BMI increased THR revision risk by 10.4% and TKR revision risk by 7.7%). We also confirmed that osteoarthritis (OA) severity and migration pattern of the hip predicted patient-reported outcome measures. The hip predictive tool that we developed performed well, with a correctedR2of 23.1% and had good calibration, with only slight overestimation of Oxford Hip Score in the lowest decile of outcome. The knee tool developed performed less well, with a correctedR2of 20.2%; however, it had good calibration. The analysis was restricted by the relatively limited number of variables available in the extant data sets, something that could be addressed in future studies. We found that the use of bisphosphonates reduced the risk of revision knee and hip surgery by 46%. Hormone replacement therapy reduced the risk by 38%, if used for at least 6 months postoperatively. We found that an increased risk of postoperative fracture was prevented by bisphosphonate use. This result, being observational in nature, will require confirmation in a randomised controlled trial. The Markov model distinguished between outcome categories following primary and revision procedures. The resulting outcome prediction tool for THR and TKR reduced the number and proportion of unsatisfactory outcomes after the operation, saving NHS resources in the process. The highest savings per quality-adjusted life-year (QALY) forgone were reported from the oldest patient subgroups (men and women aged ≥ 80 years), with a reported incremental cost-effectiveness ratio of around £1200 saved per QALY forgone for THRs. In the prospective cohort of arthroplasty, the performance of the knee model was modest (R2 = 0.14) and that of the hip model poor (R2 = 0.04). However, the addition of the radiographic OA variable improved the performance of the hip model (R2 = 0.125 vs. 0.110) and high-sensitivity C-reactive protein improved the performance of the knee model (R2 = 0.230 vs. 0.216). These data will ideally need replication in an external cohort of a similar design. The data are not necessarily applicable to other health systems or countries.

Conclusion

The number of total hip and knee replacements will increase in the next decade. High BMI, although clinically insignificant, is associated with an increased risk of revision surgery and postoperative complications. Preoperative pain/function, the pattern of joint space narrowing, deprivation index and level of education were found to be the strongest predictors for THR. Bisphosphonates and hormone therapy proved to be beneficial for patients undergoing lower limb replacement. The addition of new predictors collected from the prospective cohort of arthroplasty slightly improved the performance of the predictive tools, suggesting that the potential improvements in both tools can be achieved using the plethora of extra variables from the validation cohort. Although currently it would not be cost-effective to implement the predictive tools in a health-care setting, we feel that the addition of extensive risk factors will improve the performances of the predictive tools as well as the Markov model, and will prove to be beneficial in terms of cost-effectiveness. Future analyses are under way and awaiting more promising provisional results.

Future work

Further research should focus on defining and predicting the most important outcome to the patient.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

Morbidity and Mortality in Elective Total Knee Arthroplasty Following Surgical Care Improvement Project Guidelines

BACKGROUND

Perioperative myocardial infarctions and cardiac complications are leading causes of mortality after noncardiac surgery. In an effort to improve patient safety, the Surgical Care Improvement Project (SCIP) implemented guidelines concerning administration of β-blockers therapy aimed to reduce cardiac complications.

METHODS

The Nationwide Inpatient Sample was queried for 759,819 elective total knee arthroplasties performed from 2003 to 2011. Incidence of cardiac complications, mortality, and risk factors for cardiac complications was determined before and after SCIP implementation.

RESULTS

The incidence of cardiac events after total knee arthroplasty remained stable at 9%. The incidence and mortality of postoperative stroke, myocardial infarction, and cardiac arrest significantly decreased. Mortality after cardiac complications decreased by 50%.

CONCLUSION

After the implementation of SCIP guidelines, there was a greater than 50% reduction in mortality and a significant decrease in fatal postoperative stroke, heart failure, and cardiac arrest.

Racial and Ethnic Disparities in Utilization Rate, Hospital Volume, and Perioperative Outcomes After Total Knee Arthroplasty

BACKGROUND

Previous studies of racial disparities in total joint replacement, particularly total knee arthroplasty, in the U.S. have predominantly focused on disparities between blacks and whites and were limited to Medicare patients or veterans, populations that are not representative of the entire U.S.

POPULATION

We sought to study racial disparities in the utilization of total knee arthroplasty, the use of high-volume hospitals, and total knee arthroplasty outcomes, including mortality and complications, using all-payer databases.

METHODS

We analyzed data from 8 years and 8 racially diverse states in the State Inpatient Databases (SID). Patient race was categorized according to the SID as white, black, Hispanic, Asian, Native American, and mixed race. Both crude and adjusted racial and/or ethnic disparities were evaluated.

RESULTS

In comparison with whites (4.65 per 1000 population per year), black (3.90), Hispanic (3.71), Asian (3.89), Native American (4.40), and mixed-race (3.69) populations had lower rates of total knee arthroplasty utilization (p < 0.0001). After risk adjustment, the rate of total knee arthroplasty utilization was significantly lower for blacks (odds ratio [OR] = 0.87 [95% confidence interval (CI), 0.85 to 0.89]; p < 0.0001), Hispanics (OR = 0.76 [95% CI, 0.68 to 0.83]; p < 0.0001), Asians (OR = 0.83 [95% CI, 0.78 to 0.89]; p < 0.0001), Native Americans (OR = 0.87 [95% CI, 0.81 to 0.93]; p < 0.0001), and mixed race (OR = 0.84 [95% CI, 0.79 to 0.90]; p < 0.0001) compared with the rate for whites. Lower rates of total knee arthroplasty utilization for blacks, Hispanics, and mixed-race groups became worse over the years. Patients from minority groups were less likely to undergo total knee arthroplasty in high-volume hospitals than were whites. Moreover, the rates of mortality were significantly higher for blacks (OR = 1.52 [95% CI, 1.17 to 1.97]; p = 0.0017), Native Americans (OR = 6.52 [95% CI, 4.63 to 9.17]; p < 0.0001), and mixed-race patients (OR = 4.35 [95% CI, 3.24 to 5.84]; p < 0.0001). Blacks (OR = 1.08 [95% CI, 1.01 to 1.15]; p = 0.01) and mixed-race patients (OR = 1.17 [95% CI, 1.001 to 1.36]; p = 0.04) had higher rates of complications than whites.

CONCLUSIONS

Minorities had lower rates of total knee arthroplasty utilization but higher rates of adverse health outcomes associated with the procedure, even after adjusting for patient-related and health-care system-related characteristics. Utilization rates were based on overall population as the proportion of the population with osteoarthritis requiring arthroplasty is unknown. Future studies that consider specific patient-level information with psychosocial and behavioral factors are needed.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Relationships among pain intensity, pain-related distress, and psychological distress in pre-surgical total knee arthroplasty patients: a secondary analysis

The current study aimed to examine the relationships between movement and resting pain intensity, pain-related distress, and psychological distress in participants scheduled for total knee arthroplasty (TKA). This study examined the impact of anxiety, depression, and pain catastrophizing on the relationship between pain intensity and pain-related distress. Data analyzed for the current study (N = 346) were collected at baseline as part of a larger Randomized Controlled Trial investigating the efficacy of TENS for TKA (TANK Study). Participants provided demographic information, pain intensity and pain-related distress, and completed validated measures of depression, anxiety, and pain catastrophizing. Only 58% of the sample reported resting pain >0 while 92% of the sample reported movement pain >0. Both movement and resting pain intensity correlated significantly with distress (r_s = .86, p < .01 and .79, p < .01, respectively). About three quarters to two thirds of the sample (78% for resting pain and 65% for movement pain) reported different pain intensity and pain-related distress. Both pain intensity and pain-related distress demonstrated significant relationships with anxiety, depression, and catastrophizing. Of participants reporting pain, those reporting higher anxiety reported higher levels of distress compared to pain intensity. These findings suggest that anxious patients may be particularly distressed by movement pain preceding TKA. Future research is needed to investigate the utility of brief psychological interventions for pre-surgical TKA patients.

Three-dimensional biomechanical gait characteristics at baseline are associated with progression to total knee arthroplasty

Objective

To determine if baseline 3-dimensional (3-D) biomechanical gait patterns differed between those patients with moderate knee osteoarthritis (OA) who progressed to total knee arthroplasty (TKA) and those that did not, and whether these differences had predictive value.

Methods

Fifty-four patients with knee OA had ground reaction forces and segment motions collected during gait. 3-D hip, knee, and ankle angles and moments were calculated over the gait cycle. Amplitude and temporal waveform characteristics were determined using principal component analysis. At followup 5–8 years later, 26 patients reported undergoing TKA. Unpaired t-tests were performed on baseline demographic and waveform characteristics between TKA and no-TKA groups. Receiver operating curve analysis, stepwise discriminate analysis, and logistic regression analysis determined the combination of features that best classified TKA and no-TKA groups and their predictive ability.

Results

Baseline demographic, symptomatic, and radiographic variables were similar, but 7 gait variables differed (P < 0.05) between groups. A multivariate model including overall knee adduction moment magnitude, knee flexion/extension moment difference, and stance–dorsiflexion moment had a 74% correct classification rate, with no overtraining based on cross-validation. A 1-unit increase in model score increased by 6-fold the odds of progression to TKA.

Conclusion

In addition to the link between higher overall knee adduction magnitude and future TKA, an outcome of clear clinical importance, novel findings include altered sagittal plane moment patterns indicative of reduced ability to unload the joint during midstance. This combination of dynamic biomechanical factors had a 6-fold increased odds of future TKA; adding baseline demographic and clinical factors did not improve the model.

Changes in dimensions of total knee arthroplasty anterior knee dressings during flexion: Preliminary findings

INTRODUCTION

Wound care is critical to the management of patients post total knee arthroplasty, requiring prudent selection of dressings that can accommodate changes in wound length during knee flexion. This study aims to quantify differences in dressing dimensions based on the position of the knee during the application of the dressing and subsequent flexion.

METHODS

Our study involved 40 knees divided into 2 groups, an extension group and a flexion group, each consisting of 20 knees. These groups had dressings applied to the knee in full extension and in 90° of flexion respectively. Measurements of the dressings were taken for the extension group with the knee in extension and for both groups at 90° of flexion.

RESULTS

For the extension group, the changes in length and breadth of the dressings when measured in 90° of flexion were 3.42 ± 0.15 cm, p < 0.001 and -0.43 ± 0.10 cm, p < 0.001 respectively. Compared to the flexion group, the differences in length and breadth between the dressings when measured in 90° of flexion were 3.48 ± 0.15 cm, p < 0.001 and -0.14 ± 0.12 cm, p < 0.001 respectively.

CONCLUSION

There are significant differences and changes in the dimensions of knee dressings depending on the position of the knee during the application of dressing and subsequent flexion.

The incidence of late prosthetic joint infections: a registry-based study of 112,708 primary hip and knee replacements

BACKGROUND AND PURPOSE

Late prosthetic joint infections (PJIs) are a growing medical challenge as more and more joint replacements are being performed and the expected lifespan of patients is increasing. We analyzed the incidence rate of late PJI and its temporal trends in a nationwide population.

PATIENTS AND METHODS

112,708 primary hip and knee replacements performed due to primary osteoarthritis (OA) between 1998 and 2009 were followed for a median time of 5 (1-13) years, using data from nationwide Finnish health registries. Late PJI was detected > 2 years postoperatively, and very late PJI was detected > 5 years postoperatively.

RESULTS

During the follow-up, involving 619,299 prosthesis-years, 1,345 PJIs were registered: cumulative incidence 1.20% (95% CI: 1.13-1.26) (for knees, 1.41%; for hips, 0.92%). The incidence rate of late PJI was 0.069% per prosthesis-year (CI: 0.061-0.078), and it was greater after knee replacement than after hip replacement (0.080% vs. 0.057%, p = 0.006). The incidence rate of very late PJI was 0.051% per prosthesis-year (CI: 0.042-0.063), 0.058% for knees and 0.044% for hips (p = 0.2). The incidence rate of late PJI varied between 0.041% and 0.107% during the years of observation without any temporal trend (incidence rate ratio (IRR) = 0.98, 95% CI: 0.93-1.03). Very late PJI increased from 0.026% in 2004 to 0.056% in 2010 (IRR = 1.11, 95% CI: 1.02-1.20).

INTERPRETATION

In our nationwide study, the incidence rate of late PJI after hip or knee arthroplasty was approximately 0.07% per prosthesis-year. The incidence of very late PJI appeared to increase.