A population-based study of trends in the use of total hip and total knee arthroplasty, 1969-2008

Unicompartmental knee arthroplasty approximates healthy knee kinematics more closely than total knee arthroplasty

Total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) are effective surgeries to treat end-stage knee osteoarthritis. Clinicians assume that TKA alters knee kinematics while UKA preserves native knee kinematics; however, few studies of in vivo kinematics have evaluated this assumption. This study used biplane radiography to compare side-to-side tibiofemoral kinematics during chair rise, stair ascent, and walking in 16 patients who received either TKA or UKA. We hypothesized that TKA knees would have significant kinematic changes and increased asymmetry with the contralateral knee, while UKA knee kinematics would not change after surgery and preoperative knee symmetry would be maintained. Native bone and implant motion were tracked using a volumetric model-based tracking technique. Six degrees of freedom kinematics were calculated throughout each motion. Kinematics were compared between the operated and contralateral knees pre- and post-surgery using a linear mixed-effects model. TKA knees became less varus with the tibia more medial, posterior, and distal relative to the femur. UKA knees became less varus with the tibia less lateral on average. Postoperative TKA knees were in less varus than UKA knees on average and at low flexion angles, with an internally rotated tibia during chair rise and stair ascent. At high flexion angles, the tibia was more medial and posterior after TKA than UKA. Side-to-side kinematic symmetry worsened after TKA but was maintained or improved after UKA. Greater understanding of kinematic differences between operated and contralateral knees after surgery may help surgeons understand why some patients remain unsatisfied with their new knees.

Disparities in Total Knee and Total Hip Arthroplasty Rates in the Population of Alaska, 2015 to 2018

OBJECTIVE

Racial and ethnic disparities in total joint replacements have been documented. Our objective was to determine the rates of total joint replacements for Alaska Native/American Indian (AN/AI) individuals compared with non-AN/AI individuals in Alaska and investigate the differences in characteristics and outcomes by race.

METHODS

We used hospital discharge data from the Alaska Health Facilities Data Reporting Program from 2015 to 2018. We identified people with an inpatient primary or revision total knee arthroplasty (TKA) or total hip arthroplasty (THA). We determined the population proportion of each procedure, age-adjusted rates by race, age-specific rates, and multivariable adjusted rate ratios for TKA or THA. We compared the characteristics of people undergoing primary TKA and THA by race.

RESULTS

In 2,195,806 person-years, there were 8,131 arthroplasty procedures (4,594 primary TKAs, 2,791 primary THAs, 378 revision TKAs, and 368 revision THAs). Primary TKAs and THAs were less likely in people of AN/AI or "Other" race compared with people of White race, with some heterogeneity in the "Other" race category. In multivariable models, the adjusted rate ratio for AN/AI compared with White race for TKA was 0.70 (95% confidence interval [CI] 0.60-0.82) and for THA was 0.69 (95% CI 0.55-0.85). AN/AI individuals undergoing TKA and THA were more likely to reside in rural locations, be younger than 65 years, have longer hospital stay, and discharge to home.

CONCLUSION

This study confirmed the existence of racial disparities in TKA and THA in Alaska. There may be many underlying causes, and future research should focus on improving access to care.

Occupational and Functional Outcomes following Patellofemoral Arthroplasty in U.S. Military Servicemembers

The functional outcomes in patients undergoing patellofemoral arthroplasty (PFA) with high occupational demands have not been fully examined. This study assessed return to work and conversion to TKA rates following PFA in a young, military cohort. Patient demographics, pain scores, and surgical information were retrospectively collected for all active-duty military members who underwent PFA over a 4-year period. The data were then analyzed to calculate return to work, conversion to TKA, and perioperative complications rates. A total of 48 servicemembers with 60 total PFAs (36 unilateral, 12 bilateral) were included, with a mean follow up of 2.2 years. At the final follow-up, 83% of servicemembers returned to military service or completed their service obligation after PFA. Conversion to TKA occurred in three (6.2%) patients at an average of 2.4 years after PFA, resulting in a PFA annual revision rate of 2.3%. The mean numeric rating scale for pain improved from 4.9 ± 2.6 at baseline to 2.5 ± 2.0 postoperatively (p < 0.001). Servicemembers with at least one prior ipsilateral knee procedure had a significantly decreased odds ratio (OR) for both occupational outcome failure (OR, 0.03; 95% confidence interval [CI], 0-0.29) and overall failure (OR, 0.13; 95% CI, 0.02-0.78). At an average of 2 years following PFA, 83% of military members returned to duty, with a low rate of revision to TKA. Prior ipsilateral knee procedure decreased the probability of medical separation. LEVEL OF EVIDENCE:  IV.

Establishing the Minimally Important Difference for the KOOS-Joint Replacement and PROMIS Global-10 in Patients After Total Knee Arthroplasty

Background

Despite the overall prevalence and success of total knee arthroplasty (TKA), a significant portion of patients are dissatisfied with their outcomes.

Purpose

To assess the responsiveness and determine the minimally important difference (MID) of 2 patient-reported outcome measures (PROMs)-the Knee injury and Osteoarthritis Outcome Score-Joint Replacement (KOOS-JR) and the Patient-Reported Outcomes Measurement Information System Global-10 (PROMIS 10)-in patients after TKA.

Study Design

Cohort study (diagnosis); Level of evidence, 3.

Methods

Included were patients who underwent TKA from August 2015 through August 2019 and completed baseline and postoperative KOOS-JR and PROMIS 10 surveys. The PROMIS 10 consists of 2 domains: physical health and mental health. Estimates for the reliable change index (RCI) and MID, using anchor-based and distribution-based methods, were calculated for each PROM. Regression modeling was used to determine whether patient and clinical factors predicted MID thresholds or MID achievement.

Results

A total of 1315 patients were included. Distribution-based MIDs, calculated using various methods from baseline scores, ranged from 19.3 to 31 for the KOOS-JR, and the RCI was 4.38. Of these patients, 293 (22.3%) demonstrated small or moderate improvement, and this cohort was included in the calculation of anchor-based MIDs. The anchor-based MIDs were 16.9 and 24.3 at 3-month and 1-year follow-up, respectively, and 66% of patients achieved the MID at 12 months. Higher preoperative PROM score, male sex, non-White race, and current smoker status were predictive of failing to achieve the anchor-based MID for KOOS-JR at 1 year postoperatively (P < .05). Higher preoperative PROM score and any 90-day adverse event predicted lower thresholds of important change in anchor-based MIDs. Higher baseline PROM scores, younger age, male sex, non-White ethnicity, higher American Society of Anesthesiologists classification, preoperative narcotics use, not smoking, and longer hospital stay were all associated with lower odds of achieving the MID on the KOOS-JR or either of the PROMIS 10 subscales.

Conclusion

The study results demonstrated relevant values for interpretation of the KOOS-JR and PROMIS 10. While patient demographics did not accurately predict which patients would achieve the MID, some potential factors predicting successful patient-reported outcomes after TKA were identified.

The causal relationship between psoriasis and artificial joint re-operation after arthroplasty: A two-sample Mendelian randomization study

BACKGROUND

Psoriasis is observationally associated with a higher risk of complications of arthroplasty; however, the causal effects of psoriasis on complications of arthroplasty are yet to be established. This study was to explore the causal effect of psoriasis on artificial joint re-operation after arthroplasty through two-sample Mendelian randomization (MR).

METHODS

In the MR analysis, psoriasis was selected as the exposure in this study while single-nucleotide polymorphisms (SNPs) from a genome-wide association study (GWAS) were selected as the instrumental variables (IVs). Summary statistics data on artificial joint re-operation was extracted from publicly available GWAS data, including 218 792 European descent individuals. MR analysis was performed using the standard inverse variance weighted method (IVW). Furthermore, MR Egger, weighted median, simple mode, weighted mode, and the MR-PRESSO (Mendelian Randomization Pleiotropy Residual Sum and Outlier) test were also done to verify the results. Finally, the sensitivity analysis was executed.

RESULTS

The IVW showed that psoriasis increases the risk of artificial joint re-operation (OR = 1.12; 95% CI = (1.01, 1.25); p = 0.036). This outcome was also verified by other methods including weighted median (OR = 1.16; 95% CI = (1.03, 1.31); p = 0.015), MR Egger (OR = 1.22; 95% CI = (1.03, 1.44); p = 0.038), and weighted mode (OR = 1.16; 95% CI = (1.03, 1.30); p = 0.025). No heterogeneity and directional pleiotropy were observed upon sensitivity analysis.

CONCLUSION

The present study showed that psoriasis has a potential causal effect on artificial joint re-operation after arthroplasty. Further studies are warranted to elucidate the underlying mechanisms of causal associations between psoriasis on re-operation.

Outcomes of Revision Total Hip Arthroplasty in Patients 60 Years and Younger

Background

The annual volume of patients requiring revision total hip arthroplasty prior to age 60 is projected to increase considerably. Despite this, outcome data for revision THA in these younger patients remain limited. The purpose of this study was to define implant survivorship, identify risk factors for re-revision, and determine clinical outcomes of revision THA in patients aged ≤60 years.

Methods

We identified 191 revision THAs performed in patients aged ≤60 years. Minimum 4-year follow-up was obtained in 141 (73.8%) hips (mean 10.3 years [range, 4-20]). Mean age was 48 years (range, 20-60). Forty-five hips (32%) had previously been revised. Indications for index revision included aseptic loosening (28%), polyethylene wear (26%), dislocation (20%), and infection (14%). Outcome measures were Kaplan-Meier survival free from re-revision and patient-reported outcome scores (mHHS, UCLA).

Results

Survivorship free from re-revision for any cause was 78% [95% CI=70-85] at five years and 71% [62-78] at ten years. The most common indication for re-revision at both five and ten years was dislocation (12% [8-19], 16% [10-23]), followed by infection (6% [3-12], 10% [5-18]) and aseptic loosening (2% [1-7], 4% [1-11]). Mean scores were improved from baseline at six (mHHS +21.4, UCLA +0.9) and twelve years (mHHS +13.4, UCLA +0.5).

Conclusion

Revision THA in patients less than 60 years of age was associated with considerably lower rates of early loosening-related failure than historically reported. Recurrent dislocation and infection appear to remain challenges in this population. Despite improvements in survivorship from earlier studies, patient-reported functional improvements remained relatively unchanged. Level of Evidence: IV.

Revision Total Hip Arthroplasty in Octogenarians Compared with Septuagenarians: Is There a Real Difference?

BACKGROUND

The increasing frequency of total hip arthroplasty (THA) as well as an aging population indicate that the need for revision THA will continue to grow, especially in older and potentially medically complex patients. The purpose of this study was to compare THA revision indications, perioperative complications, and readmissions between octogenarian and septuagenarian patients. We hypothesized that patients aged 80 to 89 years would have similar outcomes to patients aged 70 to 79 years undergoing revision THA.

METHODS

Between 2008 and 2019, 572 revision THAs were performed at a single tertiary care hospital. Patients were stratified by age group: 70 to 79 years (n = 407) and 80 to 89 years (n = 165). Indication for revision, perioperative medical complications, and 90-day readmission were identified for each patient. Chi-square tests and t-tests were used to compare the groups. Logistic regression was used to assess medical complications and readmissions.

RESULTS

Aseptic loosening was a more common indication for revision in patients aged 70 to 79 years (33.4% versus 26.7%; p < 0.001), while periprosthetic fracture was a more common indication for revision in those aged 80 to 89 years (30.9% versus 13.0%). Perioperative medical complications occurred more often in octogenarians (10.9% versus 3.0%; p = 0.001), with arrythmia being the most common type. Patients aged 80 to 89 years were at increased risk for medical complications (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.5 to 7.3; p = 0.004) and readmission (OR, 3.2; 95% CI, 1.7 to 6.3; p < 0.001) when adjusting for body mass index (BMI) and indication for revision. Octogenarians had a higher rate of reoperation following first-time revision than septuagenarians (10.3% versus 4.2%, p = 0.009).

CONCLUSIONS

Octogenarians more commonly underwent revision THA for periprosthetic fracture and had higher rates of perioperative medical complications, 90-day readmissions, and reoperations than septuagenarians. Such findings should be considered when counseling patients on both primary and revision THAs.

LEVEL OF EVIDENCE

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

Incorporating Expected Outcomes Into Clinical Decision-Making for Total Knee Arthroplasty

OBJECTIVE

Expected outcomes (e.g., expected survivorship after a cancer treatment) have improved decision-making around treatment options in many clinical fields. Our objective was to evaluate the effect of expected values of 3 widely available total knee arthroplasty (TKA) outcomes (risk of serious complications, time to revision, and improvement in pain and function at 2 years after surgery) on clinical recommendation of TKA.

METHODS

The RAND/University of California Los Angeles appropriateness criteria method was used to evaluate the role of the 3 expected outcomes in clinical recommendation of TKA. The expected outcomes were added to 5 established preoperative factors from the modified Escobar appropriateness criteria. The 8 indication factors were used to develop 279 clinical scenarios, and a panel of 9 clinicians rated the appropriateness of TKA for each scenario as inappropriate, inconclusive, and appropriate. Classification tree analysis was applied to these ratings to identify the most influential of the 8 factors in discriminating TKA appropriateness classifications.

RESULTS

Ratings for the 279 appropriateness scenarios deemed 34.4% of the scenarios as appropriate, 40.1% as inconclusive, and 25.5% as inappropriate. Classification tree analyses showed that expected improvement in pain and function and expected time to revision were the most influential factors that discriminated among the TKA appropriateness classification categories.

CONCLUSION

Our results showed that clinicians would use expected postoperative outcome factors in determining appropriateness for TKA. These results call for further work in this area to incorporate estimates of expected pain/function and revision outcomes into clinical practice to improve decision-making for TKA.

Knee Injury and Osteoarthritis Outcome Score Trajectories After Primary Total Knee Arthroplasty in United States Veterans

INTRODUCTION

The volume of total knee arthroplasty (TKA) procedures continues to increase, including among United States (US) veterans, but there is little data characterizing recovery using validated knee-related questionnaires.

METHODS

In this prospective cohort study, we sought to establish the feasibility of longitudinal characterization of recovery after TKA using the validated Knee Injury and Osteoarthritis Outcome Score (KOOS), specifically focusing on two of the KOOS subscales (pain and quality of life (QOL)). We solicited participants who agreed to fill out these knee-related questionnaires preoperatively and 3, 6, and 12 months after discharge following unilateral TKA within the Durham Veterans Affairs Health Care System. We examined rates of prospective completion of the KOOS and face validity of scores at each study time point. We transformed and reported scores on the 0-100 scale, with zero representing significant knee pain or poor QOL and 100 representing no knee pain or good QOL.

RESULTS

Of 200 US veterans presenting between May 2017 and 2018, 21 (10.5%) agreed to participate by filling out the KOOS questionnaire longitudinally from before surgery until one year after discharge. All 21 (100%) participants were male and completed the two KOOS subscale questions (pain and QOL) preoperatively. Of those, 16 (76.2%) also completed KOOS at 3 months, 16 (76.2%) at 6 months, and seven (33.3%) at 12 months. Compared to mean preoperative values (pain: 33.47 + 6.78, QOL: 11.91 + 4.99), the KOOS subscale scores had significantly improved by 6 months after TKA (pain: 74.41 + 10.72, QOL: 49.61 + 13.25) but plateaued at 12 months (pain: 74.60 + 20.80, QOL: 50.89 + 20.61). The magnitude of improvement in absolute scores, pain and QOL, was similar and significant at 12 months compared to preoperative values with an increase of 41.13 (p=0.007) and 38.98 (p=0.009), respectively.

CONCLUSION

Primary TKA in US veterans with advanced osteoarthritis may lead to improved patient-reported KOOS pain and QOL subscale measures at 12 months compared to preoperative scores, with the majority of improvement occurring by 6 months. Only one in ten US veterans approached preoperatively agreed to complete the validated knee-related outcomes questionnaire prior to undergoing TKA. About three-quarters of those veterans also completed it both three and six months after discharge. Collected KOOS subscale scores demonstrated face validity and showed substantial improvement in pain and QOL over the six-month postoperative period. Only one in three veterans who completed the KOOS questionnaire preoperatively also completed it at 12 months, but this does not support the feasibility of follow-up assessments beyond 6 months. To better understand longitudinal pain and QOL trajectories in US veterans undergoing primary TKA for advanced osteoarthritis and to improve study participation, additional research using the KOOS questionnaire may add further insights into this underreported population.

Demographic changes and surgery caseloads for hip arthroplasty over the last 50 years: a retrospective study

AIMS OF THE STUDY

Data on the demographic changes over time for hip arthroplasty are rare in Switzerland. The aim of the study was to evaluate the influence of these changes on the distribution of age, gender, operated hip side, place of residence and caseload per surgeon over the last 50 years of hip arthroplasty at the Kantonsspital St. Gallen.

METHODS

For this retrospective explorative study, data were collected from the operating theatre journals of hip replacements performed at Kantonsspital St. Gallen from 1969 to 2019. Every fifth year was included, which resulted in 5-year sampling rate over the observation period. The journals were handwritten until 1999 and digital from 2004 to 2019. The following data were obtained: age, sex, type of hip arthroplasty, side of operated hip, place of residence and name of main surgeon. Apart from overall descriptive statistics, we applied the Mann-Whitney U-test to test for differences in age and the binomial test for categorical variables. A linear regression model was applied to investigate the relationship between patients' ages and historical data of life expectancy of the Swiss population.

RESULTS

We included 2,963 patients, of whom 1,318 were men (median age = 67 yr., p25 = 59 yr., p75 = 74 yr.) and 1,608 women (median age = 72 yr., p25 = 63 yr., p75 = 79 yr.). Overall, women were significantly older than men, irrespective of whether they received primary total hip arthroplasty (median age = 70 yr. vs 66 yr., p25 = 61 yr. vs 58 yr., p75 = 77 yr. vs 73 yr., p <0.001), hemiarthroplasty (median age = 84 yr. vs 78.5 yr., p25 = 78 yr. vs 71 yr., p75 = 89 yr. vs 85 yr., p <0.001) or total revision arthroplasty (median age = 71 yr. vs 70 yr., p25 = 64.25 yr. vs 63 yr., p75 = 78 yr. vs 75 yr., p = 0.036). A trend toward rising median age is evident looking at the whole period observed from 1969 to 2019. Except for women in the total revision arthroplasty group (r = 0.226), a high correlation between increasing median age of patients undergoing hip replacement and life expectancy was found (r ≥0.663). Significantly more primary total hip prostheses (p = 0.003) and hip hemiprostheses (p <0.001) were implanted in women than in men between 1969 and 2019. Overall, no significant difference in side distribution was seen in the primary total hip arthroplasty (p = 0.061), total revision arthroplasty (p = 1.000) and hemiarthroplasty (p = 0.365) group. In contrast to earlier years, most patients in recent years are operated on by high-volume surgeons (>50 operations per surgeon per year).

CONCLUSIONS

Demographic changes of patients undergoing total hip replacement reflect the overall demographic changes in the Swiss population. Over the last 50 years the indication for prosthetic hip replacements has not been extended to younger ages. The caseload in hip arthroplasty has changed over the last 50 years towards high-volume surgeons.

Comparison of general and regional anesthesia on short-term complications in patients undergoing total knee arthroplasty: A retrospective study using national health insurance service-national sample cohort

This retrospective study compared the mortality and short-term complications according to the choice of general anesthesia or regional anesthesia in patients who underwent a total knee arthroplasty (TKA). We searched the Korean National Health Insurance Service National Sample Cohort database to analyze data from patients who received a TKA between January 2002 and December 2015. Before comparing the general and the regional anesthesia groups, the bias was reduced by propensity score matching. After matching, the mortality and complications occurring within 30 days after a TKA were compared between the 2 groups. In the database, 6491 primary TKA cases were identified. Nine hundred forty-three patients (14.5%) had a TKA performed under general anesthesia, and 5548 (85.5%) had a TKA performed under regional anesthesia. After propensity score matching, the data of 1886 patients were analyzed, with 943 patients in each group. There was no significant difference in mortality (0.32% vs 0.00%), transfusion rate (84.52% vs 84.73%, P = .8989), and length of hospital stay (50 vs 53, P = .5391) between the general and regional anesthesia groups. Most of the complications were not significantly different, but the major complications, including myocardial infarction (1.70% vs 0.64%, P = .0414) and acute renal failure (0.85% vs 0.11%, P = .0391), were higher in the general anesthesia group than in the regional anesthesia group. Also, admission to the intensive care unit (8.48% vs 2.33%, P < .0001) and total cost (₩8067, 400 vs ₩7487, 940, P = .0002) were higher in the general anesthesia group than in the regional anesthesia group. Our study found that regional anesthesia for TKA is associated with a decrease in major complications, including myocardial infarction and acute renal failure, and medical costs.

Predicting pain after standard pain therapy for knee osteoarthritis - the first steps towards personalized mechanistic-based pain medicine in osteoarthritis

OBJECTIVES

The prevalence of osteoarthritis (OA) is rising, and pain is the hallmark symptom of OA. Pain in OA is complicated and can be influenced by multiple joint-related factors and factors related to, e.g., physiological, epigenetic, and pain sensory profiles. Increasing evidence suggests that a subset of patients with OA are pain sensitive. This can be assessed using quantitative sensory testing (QST). Common treatments of OA are total knee arthroplasty (TKA) and administration of 3-weeks of non-steroidal anti-inflammatory drugs (NSAIDs), which provide pain relief to many patients with OA. However, approx. 20% of patients experience chronic postoperative pain after TKA, whereas NSAIDs provide an average pain relief of approx. 25%. The current topical review focuses on the emerging evidence linking pretreatment QST to the treatment response of TKA and NSAID treatments.

CONTENT

MEDLINE was systematically searched for all studies from 2000 to 2022 on pretreatment QST, TKA, and NSAIDs. Pre-clinical studies, reviews, and meta-analyses were excluded.

SUMMARY

Currently, 14 studies on TKA and four studies on NSAIDs have been published with the aim to attempt prediction of the treatment response. The QST methodologies in the studies are inconsistent, but 11/14 (79%) studies on TKA and 4/4 (100%) studies on NSAIDs report statistically significant associations between pretreatment QST and chronic postoperative pain after TKA or analgesic effect after NSAID treatment. The strength of the associations remains low-to-moderate. The most consistent pretreatment QST predictors are pressure pain thresholds, temporal summation of pain, and conditioned pain modulation.

OUTLOOK

The use of QST as predictors of standard OA treatment is interesting, but the predictive strength remains low-to-moderate. A transition of QST from a research-based setting and into the clinic is not advised until the predictive strength has been improved and the methodology has been standardized.

Functional outcomes in patient specific instrumentation vs. conventional instrumentation for total knee arthroplasty; a systematic review and meta-analysis of prospective studies

Background

Total Knee Arthroplasty (TKA) is an established surgical option for knee osteoarthritis (OA). There are varying perceptions of the most suitable surgical technique for making bone cuts in TKA. Conventional Instrumentation (CI) uses generic cutting guides (extra- and intra-medullary) for TKA; however, patient specific instrumentation (PSI) has become a popular alternative amongst surgeons.

Methods

A literature search of electronic databases Embase, Medline and registry platform portals was conducted on the 16^th May 2021. The search was performed using a predesigned search strategy. Eligible studies were critically appraised for methodological quality. The primary outcome measure was Knee Society Function Score. Functional scores were also collected for the secondary outcome measures: Oxford Knee Score (OKS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS) and Visual Analog Scale (VAS) for pain. Review Manager 5.3 was used for all data synthesis and analysis.

Results

There is no conclusive evidence in the literature to suggest that PSI or CI instrumentation is better for functional outcomes. 23 studies were identified for inclusion in this study. Twenty-two studies (18 randomised controlled trials and 4 prospective studies) were included in the meta analysis, with a total of 2277 total knee arthroplasties. There were 1154 PSI TKA and 1123 CI TKA. The majority of outcomes at 3-months, 6-months and 12 show no statistical difference. There was statistical significance at 24 months in favour of PSI group for KSS function (mean difference 4.36, 95% confidence interval 1.83–6.89). The mean difference did not exceed the MCID of 6.4. KSS knee scores demonstrated statistical significance at 24 months (mean difference 2.37, 95% confidence interval (CI) 0.42—4.31), with a MCID of 5.9. WOMAC scores were found to be statistically significant favouring PSI group at 12 months (mean difference -3.47, 95% confidence interval (CI) -6.57- -0.36) and 24 months (mean difference -0.65, 95% confidence interval (CI) -1.28—-0.03), with high level of bias noted in the studies and a MCID of 10.

Conclusions

This meta-analysis of level 1 and level 2 evidence shows there is no clinical difference when comparing PSI and CI KSS function scores for TKA at definitive post operative time points (3 months, 6 months, 12 months and 24 months). Within the secondary outcomes for this study, there was no clinical difference between PSI and CI for TKA. Although there was no clinical difference between PSI and CI for TKA, there was statistical significance noted at 24 months in favour of PSI compared to CI for TKA when considering KSS function, KSS knee scores and WOMAC scores. Studies included in this meta-analysis were of limited cohort size and prospective studies were prone to methodological bias. The current literature is limited and insufficiently robust to make explicit conclusions and therefore further high-powered robust RCTs are required at specific time points.

Occupational Outcomes and Revision Rates for Medial Unicondylar Knee Arthroplasty in U.S. Military Servicemembers

This study evaluates return to work and revision rates for medial unicondylar knee arthroplasty (UKA) in a high-demand military cohort. Patient demographic and clinical variables were isolated from the medical records of active-duty military servicemembers with at least 2 years of postoperative follow-up and correlated with return to work, medial UKA survivorship, and perioperative complications. The medial UKA annual revision rate was calculated as the percentage of implants revised per observed component year. A total of 39 servicemembers underwent 46 primary medial UKAs (32 unilateral and 7 bilateral) with a mean follow-up of 3.9 (2.0-6.6) years. At a minimum of 2 years postoperatively, 33 (85%) servicemembers returned to military service or successfully completed their service obligation. Older servicemembers (odds ratio [OR] = 0.67; 95% confidence interval [CI]: 0.45, 0.99) had a significantly decreased OR for knee-related medical separation. Nine servicemembers (20%) had conversion to TKA at an average of 2.4 (range, 0.6-5.6) years with a medial UKA annual revision rate of 5%. When compared with Navy/Air Force, Army/Marine servicemembers had an increased TKA conversion rate (OR = 5.40; 95% CI: 1.13, 25.81). Older age decreased the likelihood of medical separation and Army/Marines service was the sole risk factor associated with conversion to TKA. The level of evidence is IV, therapeutic case series.

Patient reported outcomes measures (PROMs) trajectories after elective hip arthroplasty: a latent class and growth mixture analysis

Background

Patient-reported outcome measures (PROMs) are an extensively used tool to assess and improve the quality of healthcare services. PROMs can be related to individual demographic and clinical characteristics in patients undergoing hip arthroplasty (HA). The aim of this study is to identify distinct subgroups of patients with unique trajectories of PROMS scores and to determine patients’ features associated with these subgroups.

Methods

We conducted a prospective, cohort study in which PROMs questionnaires (Euro Quality 5 Dimensions 3L, EQ-5D-3L, Euro-Quality-Visual-Analytic-Score, EQ-VAS, Hip disability and Osteoarthritis Outcome Score, HOOS-PS) were administered to patients undergoing elective HA pre-operatively, and at 6 and 12 months after surgery. For each measure, latent class growth analysis and growth mixture models were used to identify subgroups of patients with distinct trajectories of scores. Demografic and clinical predictors of the latent classes in growth mixture model were identified using a 3-step approach.

Results

We found three distinct trajectories for each PROM score. These trajectories indicated a response heterogeneity to the HA among the patients (n = 991). Patient’s gender, ASA score, and obesity were significantly associated with different PROMs trajectories.

Conclusions

We identified three distinct trajectories for each of the three PROMs indicators. Several demographic and clinical characteristics are associated with the different trajectories of PROMs at 6 and 12 months after HA and could be used to identify groups of patients with different outcomes following HA surgery. These findings underline the importance of patient-centered care, supporting the usefulness of integrating PROMs data alongside routinely collected healthcare records for guiding clinical care and maximizing patients’ positive outcomes.

Trial registration: Protocol version (1.0) and trial registration data are available on the platform www.clinicaltrial.gov with the identifier NCT03790267, posted on December 31, 2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41687-022-00503-5.

Projected Prevalence of Obesity in Primary Total Knee Arthroplasty: How Big Will the Problem Get?

BACKGROUND

Obesity is a well-established risk factor for complications following primary total knee arthroplasty (TKA). The purpose of this study is to utilize 3 national databases to develop projections of obesity within the general population and primary TKA patients in the United States through 2029.

METHODS

Data from the National Surgical Quality Improvement Program (NSQIP), the Behavior Risk Factor Surveillance System (BRFSS), and the National Health and Nutrition Examination Survey were queried for years 1999-2019. Current Procedural Terminology code 27447 was used to identify primary TKA patients in NSQIP. Individuals were categorized according to body mass index (kg/m²) by year: normal weight (≤24.9); overweight (25.0-29.9); obese (30.0-39.9); and morbidly obese (≥40). Multinomial logistic regression was used to project categorical body mass index data for years 2020-2029.

RESULTS

A total of 8,372,221 individuals were included (7,986,414 BRFSS, 385,807 NSQIP TKA). From 2011 to 2019, the prevalence of normal weight and overweight individuals declined in the general population (BRFSS) and in primary TKA. Prevalence of obese/morbidly obese individuals increased in the general population from 31% to 36% and in primary TKA from 60% to 64%. Projection models estimate that by 2029, 46% of the general population will be obese/morbidly obese and 69% of primary TKA will be obese/morbidly obese.

CONCLUSION

By 2029, we estimate ≥69% of primary TKA to be obese/morbidly obese. Increased resources dedicated to care pathways and research focused on improving outcomes in obese arthroplasty patients will be necessary as this population continues to grow.

LEVEL OF EVIDENCE

Level III, Retrospective Cohort Study.

Effects of Electromyographic Biofeedback on Functional Recovery of Patients Two Months after Total Knee Arthroplasty: A Randomized Controlled Trial

The incidence of total knee arthroplasty (TKA) is steadily increasing worldwide. Therefore, it is crucial to develop efficient rehabilitation protocols and investigate the innovations in medical technology, which could improve rehabilitation outcomes. The aim of the study was to investigate the effect of adding electromyographic biofeedback (EMG-BF) to the conventional program of rehabilitation after TKA on quality of life, intensity of pain, and functional performance. The study was designed as a randomized controlled trial. A total of 131 patients were randomly assigned to two groups: an experimental group (n = 67; median age 70 (IQR 10)), and a control group (n = 64; median age 69 (IQR 9)). Both groups participated in an inpatient program of 21 days of rehabilitation, including land-based and aquatic exercise therapy, electrotherapy, and education. In the experimental group, a portion of land-based exercise therapy was supplemented by EMG-BF. A numeric rating scale (NRS), Knee Injury and Osteoarthritis Outcome Score (KOOS), use of mobility aids, 30 s chair stand test (CST), and timed up and go (TUG) test were used to measure outcomes. Both groups improved their functional abilities from day 1 to day 21 of rehabilitation. A higher proportion of participants did not use a walking aid (p < 0.002), and their NRS, KOOS, 30 s CST and TUG scores improved (p < 0.001). There were no significant differences between the groups in the outcomes. EMG-BF did not provide additional benefits to the conventional rehabilitation after TKA.

Location of Initial Closed Reduction Attempt Significantly Increases Cost and Length of Stay in Total Hip Arthroplasty

Background

Prosthetic hip dislocation remains one of the most frequent complications following total hip replacement. Dislocations are predominantly managed by a closed reduction in the emergency department (ED) or the operating room (OR). This study aimed to evaluate how the location of an initial closed reduction attempt impacts a patient's course of care including length of stay (LOS) and cost of care.

Material and methods

A retrospective chart review was performed on all patients presenting to a single ED with a unilateral prosthetic hip dislocation from 2009 to 2019. A total of 108 patients were identified. Data collected included patient demographics, ED/hospital course, and hospital charges.

Results

Seventy-four patients (69%) had initial reduction attempted in the ED (65/74, 88% were successful), while 34 patients (31%) went directly to OR (100% successful with closed reduction). Failed closed reduction in ED or direct to OR resulted in a greater LOS and rate of placement to a skilled nursing facility following discharge. Median hospital charges for successful ED reduction were $6,837, while failed ED closed reduction or direct to OR resulted in median charges of $27,317 and $20,481, respectively.

Conclusion

Many patients successfully underwent closed reduction in the ED, and there was no difference in complications, independent of where the reduction was first performed. Patients undergoing reduction in the OR had greater LOS and cost of care, independent of whether a reduction attempt was performed and failed in the ED, than those successfully reduced in the ED.

Early Virtual-Reality-Based Home Rehabilitation after Total Hip Arthroplasty: A Randomized Controlled Trial

The benefits of early virtual-reality-based home rehabilitation following total hip arthroplasty (THA) have not yet been assessed. The aim of this randomized controlled study was to compare the efficacy of early rehabilitation via the Virtual Reality Rehabilitation System (VRRS) versus traditional rehabilitation in improving functional outcomes after THA. Subjects were randomized either to an experimental (VRRS; n = 21) or a control group (control; n = 22). All participants were invited to perform a daily home exercise program for rehabilitation after THA with different administration methods—namely, an illustrated booklet for the control group and a tablet with wearable sensors for the VRRS group. The primary outcome was the hip disability (HOOS JR). Secondary outcomes were the level of independence and the degree of global perceived effect of the rehabilitation program (GPE). Outcomes were measured before surgery (T0) and at the 4th (T1), 7th (T2), and 15th (T3) day after surgery. Mixed-model ANOVA showed no significant group effect but a significant effect of time for all variables (p < 0.001); no differences were observed in HOOS JR between VRRS and the control at T0, T1, T2, or T3. Further, no differences in the level of independence were found between VRRS and the control, whereas the GPE was higher at T3 in VRSS compared to the control (4.76 ± 0.43 vs. 3.96 ± 0.65; p < 0.001). Virtual-reality-based home rehabilitation resulted in similar improvements in functional outcomes with a better GPE compared to the traditional rehabilitation program following THA. The application of new technologies could offer novel possibilities for service delivery in rehabilitation.

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.

Prediction of 90-Day Local Complications in Patients After Total Knee Arthroplasty: A Nomogram With External Validation

Background:

Local complications after total knee arthroplasty (TKA) significantly affect the patient’s prognosis. Nomograms can be a useful tool for predicting such complications.

Purpose:

To compare the preoperative and intraoperative factors of patients who underwent TKA with and without complications and to construct and validate a nomogram based on selective predictors of local complications within 90 days postoperatively.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

The nomogram was developed in a primary cohort that consisted of 410 patients who underwent primary TKA at the authors’ institution between January 2015 and September 2018. Predictor variables included 4 major local complications that can occur within 90 days: reoperation (including implant revision or removal for any reason and manipulation under anesthesia), infection, bleeding requiring ≥4 unit transfusion of red blood cells within 72 hours of surgery, and peripheral nerve injury. The authors used least absolute shrinkage and selection operator (LASSO) regression analysis for data dimension reduction and feature selection. Multivariable logistic regression analysis was used to develop the nomogram. Performance of the nomogram was assessed using C-index, calibration plot, area under the receiver operating characteristic curve (AUC), and decision curve analysis (DCA). The model was subjected to bootstrap validation and external validation using a prospective cohort of 249 patients.

Results:

Four significantly prognostic factors were incorporated into the nomogram: age-adjusted Charlson Comorbidity Index, American Society of Anesthesiologists score, tourniquet time, and estimated intraoperative blood loss. The model displayed good discrimination, with a C-index of 0.819 and an AUC of 0.819. The calibration curves showed optimal agreement between nomogram prediction and actual observation. A high C-index value of 0.801 could still be reached in bootstrap validation. Application of the nomogram in the validation cohort showed good discrimination (C-index, 0.731) and good calibration. DCA demonstrated that the nomogram was clinically useful.

Conclusion:

The authors developed and validated a novel nomogram that can provide individual prediction of local complications within 90 days for patients after TKA. This practical tool may be conveniently used to estimate individual risk and help clinicians take measures to minimize or prevent the incidence of complications.

Trends of Total Knee Arthroplasty According to Age Structural Changes in Korea from 2011 to 2018

Total Knee Arthroplasty (TKA) is one of the most commonly performed surgeries worldwide since it can improve pain, quality of life, and functional outcome. Due to the expansion of hospitals specialized in joint surgery, the topography of TKA implementation in Korea is changing. This study analyzed longitudinal trends of TKA based on changes in age distribution, sex, hospital, and region based on the Health Insurance Review and Assessment Service (HIRA) of Korea database. Data were collected from the National Health Insurance Service (NHIS), the Korean Statistical Information Service (KOSIS), and the Health Insurance Review and Assessment Service (HIRA) in Korea for the period 2011-2018. Results show the total number of surgeries increased and the number of patients by age decreased in those under the age of 70, while the number of patients over 70 years of age increased. A remarkable increase in women was found, and there was no significant difference between regions. TKA is spreading in a more universal and easily accessible form in Korea and has increased more in other relatively small medical institutions compared to tertiary referral medical centers. Due to the increase of orthopedics' specialized hospitals and clinics, TKA is becoming more prominent in those hospitals.

Three-dimensional morphometric differences of resected distal femurs and proximal tibias in osteoarthritic and normal knees

BACKGROUND

There is a paucity of data concerning the morphological differences of resected distal femurs and proximal tibias in osteoarthritic (OA) and normal knees. The objective of this study was to determine whether morphometric differences in the surfaces of resected distal femurs and proximal tibias exist between OA and normal knees in a Chinese population.

METHODS

Ninety-four OA knees and ninety-five normal knees were evaluated in Chinese individuals. Computed tomography was used to measure the femoral mediolateral (fML), medial anteroposterior (fMAP), lateral anteroposterior (fLAP), medial condylar width (fMCW), lateral condylar width (fLCW), medial posterior condylar curvature radii (fMCR), lateral posterior condyle curvature radii (fLCR), fML/fMAP aspect ratio, tibial mediolateral (tML), middle anteroposterior (tAP), medial anteroposterior (tMAP), and lateral anteroposterior (tLAP) tML/tMAP aspect ratio to determine the morphologic differences between OA and normal knees.

RESULTS

The average fMCW and tMAP dimensions of OA knees were larger than those of normal knees in both male and female (p <0.05). The fMAP/fML aspect ratio and tMAP/tML aspect ratio were also significantly different in both sexs (p <0.05). OA knees have an oval-shaped distal femur with a wider ML length and more spherical-shaped proximal tibiae with relatively narrow ML dimensions.

CONCLUSIONS

The study revealed the morphological differences in fMCW, tMAP, fMAP/fML and tMAP/tML between OA and normal knees in both males and females. These findings may provide guidelines that can be used to design better knee implants that are more size-matched for OA knees.

Reporting and Analyzing Demographics in the Journal of Arthroplasty: Are We Making Progress?

BACKGROUND

Demographic factors, including age, sex, body mass index (BMI), race, and ethnicity have great effects on the outcomes of patients undergoing total joint arthroplasty. A portion of this data is included in nearly every study, but the completeness with which it is reported is variable. The purpose of this study is to investigate the frequency at which demographic information is reported and analyzed through formal statistical methods in randomized controlled trials (RCTs) published in the Journal of Arthroplasty (JOA).

METHODS

A systematic review was conducted of RCTs published in JOA between 2015 and 2019. For each study, we determined if age, sex, weight, height, BMI, race, and ethnicity were reported and/or analyzed. The overall frequency was assessed, along with the rates of reporting by individual year. Studies were evaluated using Cochrane risk-of-bias tool.

RESULTS

Age (96.7%), sex (96.7%), and BMI (80.4%) were reported by the majority of studies. There was very little information provided regarding race (6.2%) and ethnicity (3.8%); although both were reported at the highest frequency in 2019, the final year of articles reviewed. Sex was the most frequently analyzed variable at 11.5%. Only 1 study (0.5%) analyzed ethnicity and no studies analyzed race.

CONCLUSION

Although age, sex, and BMI are reported at a high rate, RCTs published in JOA rarely reported information on patient race and ethnicity. Demographics were infrequently included as part of statistical analysis. The importance of this information should be recognized and included in the analysis and interpretation of future studies.

The Effect of Preoperative Behavioral Intervention on Pain, Anxiety, Opioid Use, and Function in Patients Undergoing Total Knee Arthroplasty: A Randomized Controlled Study

OBJECTIVE

To evaluate the efficacy of preoperative cognitive-behavioral psychoeducation (CBE) for improved pain, anxiety, opioid use, and postoperative function in total knee arthroplasty (TKA) patients.

METHODS

A randomized controlled trial was conducted among 36 military health system beneficiaries attending preoperative education for TKA. The standard of care (SOC) group (n = 18) received information on home safety, rehabilitation, postoperative precautions, and pain management. In addition, the occupational therapy led CBE group (n = 16) received information on principles of holistic wellness (healing process, effects of stress on healing, heart-rate control through diaphragmatic breathing, anti-inflammatory nutrition, goal setting, and mental imagery). Outcomes of interest: knee active range of motion, pain (Defense and Veterans Pain Rating Scale), opioid medication use, heart-rate coherence (emwave2), anxiety (Generalized Anxiety Disorder Scale), and function (Knee Outcome Survey Activities of Daily Living [KOS-ADL], modified Functional Independence Measure, and Global Rate of Change).

RESULTS

The CBE group demonstrated significantly greater decline in pain overall, with activity, and during sleep in relation to the SOC group when comparing visit 1 to visit 5. Opioid medication use was significantly lower for CBE versus SOC. Postoperative General Anxiety Disorder-7 scores decreased significantly among CBE participants with similar increase in high heart rate coherence. Function significantly improved postoperatively based on KOS-ADL and Global Rate of Change scores. Twice as many CBE participants had same-day discharge compared to SOC participants and most CBE participants continued with healthy lifestyle recommendations at the 3-month follow-up.

CONCLUSION

A cognitive-behavioral approach to preoperative education may improve postoperative pain, anxiety, and function while decreasing opioid use among TKA patients. Findings from this pilot study support further research to examine similar interventions among distinct surgical populations and encourage further evaluation on the effects of CBE to enhance health and healthcare delivery.

Physician induced demand for knee replacement surgery in Iran

BACKGROUND

The structure of the Iranian health system has raised this hypothesis that a part of the Knee Replacement Surgery (KRS) services are provided due to Physician-Induced Demand (PID).

METHODS

This paper used an unbalanced individual panel data covering the steady-state 15,729 KRSs performed by 995 surgeons provided by the Armed Forces Insurance Organization at the provincial level over the 60 months (2014-2018). We use a generalized method of moment's system (GMM-SYS) to obtain consistent and asymptotically efficient estimates, which provide a vital instrument for our dynamic panel data.

RESULTS

The outcomes show that with unequal increasing orthopedic surgeons to population ratio, both the number and size of KRS services were increased significantly at a 1 % level. Given that the positive elasticity obtained for the service size was significantly larger than the number of services, the findings give strong support for the existence of PID in the Iran system for KRS care. Also, the raw and population-adjusted number of KRS, cost, and the surgery per active physician increased significantly at the monthly province level.

CONCLUSIONS

This is the first time that the existence of PID in the Iranian health system is investigated using approved econometric models. The findings indicate that the health system structure has been provided the conditions for aggressive, costly, and high-risk services such as KRS to be exposed to PID.

A Randomized Controlled Trial to Compare Analgesia and Functional Improvement After Continuous Neuroablative and Pulsed Neuromodulative Radiofrequency Treatment of the Genicular Nerves in Patients with Knee Osteoarthritis up to One Year After the Intervention

OBJECTIVES

To compare the analgesic and functional outcomes of continuous neuroablative radiofrequency (CNARF) and pulsed neuromodulative radiofrequency (PNMRF) treatment of genicular nerves up to 1 year after the intervention and to identify predictors associated with a successful outcome (defined as an at least 50% reduction in the pre-interventional visual analog scale [VAS] rating) after genicular radiofrequency treatment.

DESIGN

A prospective randomized controlled trial.

SETTING

The Pain Department of the Jerez de la Frontera University Hospital, Cadíz, Spain, from January 2018 until May 2019.

SUBJECTS

Patients with grade 3-4 gonarthritis suffering from knee pain, with a VAS score ≥5 for >6 months.

METHODS

Eligible participants were randomly assigned to receive either CNARF or PNMRF of the superior medial, superior lateral, and inferior medial genicular nerves. The VAS and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) scores were assessed before and at 1, 6, and 12 months after treatment. Medication use was quantified before and at 6 months after the intervention. Potential characteristics associated with the efficacy of radiofrequency intervention were explored by using multivariable statistical models.

RESULTS

A total of 188 participants were included. The magnitude and duration of beneficial effect and reduction in analgesic use were significantly greater in the CNARF group. Success at 6 months after radiofrequency treatment decreased with grade 4 gonarthritis; higher pre-interventional VAS score; and concomitant depression, anxiety disorder, and diabetes mellitus.

CONCLUSIONS

Therapeutic efficacy and reduction in analgesic consumption were superior after CNARF. Treatment success at 6 months after radiofrequency intervention decreased with more severe gonarthritis; higher pre-interventional pain intensity; and concomitant depression, anxiety disorder, and diabetes mellitus.

Arthroplasty Rates Not Increasing in Young Patients With Rheumatoid Arthritis: A National Database Review, 2005 Versus 2014

Background

For 20 years, authors have predicted an expansion in total knee arthroplasty (TKA) and total hip arthroplasty (THA) utilization. Over this same period, the introduction of biological disease-modifying antirheumatic drugs has dramatically altered the treatment of rheumatoid arthritis (RA) with hopes of preventing articular damage and obviating the need for prosthetic replacement. The goal of our investigation was to evaluate TKA and THA utilization in young patients with RA (<65 years) in 2005 vs 2014 compared to patients with osteoarthritis (OA).

Methods

Using relevant International Classification of Disease Ninth Revision (ICD-9) and Current Procedural Terminology codes, the Truven MarketScan Database (over 46 million enrollees) was queried to determine THA and TKA incidence rates for RA and OA patients aged <65 years during the final decade of ICD-9 use. Patients with potentially confounding ICD-9 codes were excluded to limit coding variation. Statistical analysis consisted of student t-tests, Pearson's chi-square tests, and Breslow-Day tests.

Results

For patients with OA, TKAs increased substantially from 0.07% in 2005 to 0.1% in 2014 (+42.9% change, P < .001). Similarly for patients with OA, THAs increased from 0.04% to 0.06% over the same time period (+66.0% change, P < .001). For young patients with RA, the rate of TKA remained relatively stable—1.06% in 2005 to 1.04% in 2014 (−1.7% change, P = .65)—as did THA—0.44% to 0.48% (+9.0% change, P = .14).

Conclusions

Dramatic increases in THA and TKA rates for OA patients aged <65 years were indeed observed from 2005 to 2014. This trend, however, was not seen in the RA population where TKA and THA rates remained unchanged.

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.

Postdischarge Opioid Use after Total Hip and Total Knee Arthroplasty

BACKGROUND

As America's third highest opioid prescribers, orthopedic surgeons have contributed to the opioid abuse crisis. This study evaluated opioid use after primary total joint replacement. We hypothesized that patients who underwent total hip arthroplasty (THA) use fewer opioids than patients who underwent total knee arthroplasty (TKA) and that both groups use fewer opioids than prescribed.

METHODS

A prospective study of 110 patients undergoing primary THA or TKA by surgeons at an academic center during 2018 was performed. All were prescribed oxycodone 5 mg, 84 tablets, without refills. Demographics, medical history, and operative details were collected. Pain medication consumption and patient-reported outcomes were collected at 2 and 6 weeks postoperatively. Analysis of variance was performed on patient and surgical variables.

RESULTS

Sixty-one patients scheduled for THA and 49 for TKA were included. THA patients consumed significantly fewer opioids than TKA patients at 2 weeks (28.1 tablets vs 48.4, P = .0003) and 6 weeks (33.1 vs 59.3, P = .0004). Linear regression showed opioid use decreased with age at both time points (P = .0002). A preoperative mental health disorder was associated with higher usage at 2 weeks (58.3 vs 31.4, P < .0001) and 6 weeks (64.7 vs 39.2, P = .006). Higher consumption at 2 weeks was correlated with worse outcome scores at all time points.

CONCLUSIONS

TKA patients required more pain medication than THA patients, and both groups received more opioids than necessary. In addition, younger patients and those with a preexisting mental health disorder required more pain medication. These data provide guidance on prescribing pain medication to help limit excess opioid distribution.

Total knee replacement after high tibial osteotomy: time-to-event analysis and predictors

BACKGROUND

An important aim of high tibial osteotomy (HTO) is to prevent or delay the need for total knee replacement (TKR). We sought to estimate the frequency and timing of conversion from HTO to TKR and the factors associated with it.

METHODS

We prospectively evaluated patients with osteoarthritis (OA) of the knee who underwent medial opening wedge HTO from 2002 to 2014 and analyzed the cumulative incidence of TKR in July 2019. The presence or absence of TKR on the HTO limb was identified from the orthopedic surgery reports and knee radiographs contained in the electronic medical records for each patient at London Health Sciences Centre. We used cumulative incidence curves to evaluate the primary outcome of time to TKR. We used multivariable Cox proportional hazards analysis to assess potential preoperative predictors including radiographic disease severity, malalignment, correction size, pain, sex, age, body mass index (BMI) and year of surgery.

RESULTS

Among 556 patients who underwent 643 HTO procedures, the cumulative incidence of TKR was 5% (95% confidence interval [CI] 3%-7%) at 5 years and 21% (95% CI 17%-26%) at 10 years. With the Cox proportional hazards multivariable model, the following preoperative factors were significantly associated with an increased rate of conversion: radiographic OA severity (adjusted hazard ratio [HR] 1.96, 95% CI 1.12-3.45), pain (adjusted HR 0.85, 95% CI 0.75-0.96)], female sex (adjusted HR 1.67, 95% CI 1.08-2.58), age (adjusted HR 1.50 per 10 yr, 95% CI 1.17-1.93) and BMI (adjusted HR 1.31 per 5 kng/m2, 95% CI 1.12-1.53).

INTERPRETATION

We found that 79% of knees did not undergo TKR within 10 years after undergoing medial opening wedge HTO. The strongest predictor of conversion to TKR is greater radiographic disease at the time of HTO.

Gout in primary total knee arthroplasty: Prevalent but not independently associated with complications

BACKGROUND

Gout is a common synovial pathology, but its prevalence in patients undergoing total knee arthroplasty (TKA) and potential association with complications such as periprosthetic infection (PJI) and revision are unknown.

METHODS

Medicare data from 2009 to 2013 was retrospectively reviewed using PearlDiver. All patients 65 years of age or older and undergoing primary TKA with at least 3 years of pre-TKA records were included. The prevalence of gout was based on ICD-9 codes. Univariable associations of gout with PJI and revision at 1 year were assessed using odds ratios with 95% confidence intrervals (C.I.). To control for potential confounding, patients with a history of gout were matched on age, gender, smoking history, and Elixhauser Comorbidity Index (ECI) to patients without gout and associations reassessed.

RESULTS

The prevalence of gout in Medicare patients undergoing primary TKA was 5.7%. On univariable analysis, patients with a history of gout were more likely to develop PJI (O.R., 1.58; 95% C.I., 1.45-1.72) and undergo revision (O.R., 1.33; 95% C.I., 1.25-1.41) at 1 year. After matching for confounders, a history of gout was no longer associated with developing PJI (O.R., 0.98; 95% C.I., 0.90-1.06) or undergoing revision (O.R., 0.94; 95% C.I., 0.89-1.00) at 1 year.

CONCLUSIONS

Gout is a relatively common pathology in patients undergoing TKA. While gout is associated with increased complications, this appears to be driven by confounding through its association with other medical comorbidities. Gout does not appear to be an independent risk factor for complications following TKA.

Current Trends and Projected Burden of Primary and Revision Total Knee Arthroplasty in Korea Between 2010 and 2030

BACKGROUND

This study aimed to (1) document the total knee arthroplasty (TKA) use in Korea from 2010 to 2018, (2) evaluate whether rapid increase in TKA use has been maintained, and (3) estimate the projected TKA burden to 2030 based on the current use.

METHODS

Using the Health Insurance Review and Assessment Korean database, procedural rate, growth rate, and revision burden of primary and revision TKAs in Korea between 2010 and 2018 were analyzed. TKA procedural numbers were also stratified by age and gender. Then, the projected TKA burden to 2030 including procedural number and medical costs were estimated using linear and quasi-Poisson regression models, respectively.

RESULTS

Between 2010 and 2018, procedural rate of primary and revision TKAs has increased by 35% and 68%, respectively. More than 85% of primary and revision TKAs were performed on female patients, and the subgroup of patients aged ≥80 years showed a marked increase in primary and revision TKA use. According to the projection model, the number of primary and revision TKAs is predicted to increase between 53% and 91%, and between 75% and 155%, respectively, by 2030.

CONCLUSION

Between 2010 and 2018, the procedural rates of primary and revision TKAs in Korea increased gradually by 35% and 68%, respectively, and previously observed striking growth rate has markedly slowed. Nevertheless, compared to 2018, the burdens of primary and revision TKAs are projected to increase up to 91% and 155%, respectively, by 2030.

LEVEL OF EVIDENCE

Therapeutic Level III.

Class III Obesity Increases Risk of Failure to Achieve the 1-Year Hip Disability and Osteoarthritis Outcome Score-Physical Function Short Form Minimal Clinically Important Difference Following Total Hip Arthroplasty

BACKGROUND

The relationship between obesity and failure to achieve a minimal clinically important difference (MCID) following total hip arthroplasty (THA) has not been well defined. The aims of this study are to determine whether increasing body mass index (BMI) is associated with failure to achieve the 1-year Hip Disability and Osteoarthritis Outcome Score-Physical Function Short Form (HOOS-PS) MCID and to determine a threshold BMI beyond which this risk is significantly increased.

METHODS

A multi-institutional arthroplasty registry was queried for THA patients from 2016 to 2018 with completion of preoperative and 1-year postoperative HOOS-PS. A previously defined anchor-based MCID threshold of 23 was used. Variables collected included demographics and patient-reported outcome measures. BMI was analyzed continuously and categorically. The association was analyzed via logistic regression. A BMI threshold was determined using the Youden index and receiver operating characteristic curve.

RESULTS

A total of 1256 THAs were included. The average HOOS-PS improvement was 27.6 ± 18 points. The area under the receiver operating characteristic curve for BMI and risk of failure to achieve HOOS-PS MCID was 0.54 (95% confidence interval [CI], 0.50-0.57). Increasing BMI assessed continuously was a significant risk factor (odds ratio [OR], 1.03; 95% CI, 1.01-1.05; P value = .010). When BMI was analyzed categorically, this association was only observed for obese class III patients (>40 kg/m²) (OR, 2.5; 95% CI, 1.21-5.3; P value = .010).

CONCLUSION

This study found an association between increasing BMI and failure to achieve the 1-year HOOS-PS MCID. Obese class III patients (>40 kg/m²) face a near 3-fold increased risk of suffering this adverse outcome.

Fast-track rehabilitation after total knee arthroplasty reduces length of hospital stay: A prospective, case-control clinical trial

Objectives

The aim of this study was to compare the impact of fast-track rehabilitation (FTR) and conventional rehabilitation (CR) on early recovery pattern after fast-track surgery for knee arthroplasty and conventional total knee arthroplasty (TKA).

Patients and methods

This prospective, case-control study included a total of 43 adult patients (10 males, 33 females; mean age 69 years; range, 50 to 82 years) who were clinically stable and admitted for rehabilitation after fast-track surgery for knee arthroplasty or conventional TKA January 2016 and August 2016. The patients were divided into two groups as the FTR and CR treatment groups. The FTR program was designed as a patient-focused care, early mobilization, and standardized postoperative milestones. The CR program was designed by standard postoperative rehabilitation care. Primary outcomes were the length of stay (LOS) in the hospital and knee function. Secondary outcomes were pain and activities of daily living.

Results

At baseline, both groups were similar in terms of demographic data and primary outcomes. At discharge, intra-group analysis showed significant differences in both groups in all functional outcomes, except for pain, while the inter-group LOS was also significantly different (p<0.001).

Conclusion

Our study results indicate that LOS can be reduced by FTR, yielding the same results in functional recovery and autonomy as CR.

Association Between Acupuncture and Knee Surgery for Osteoarthritis: A Korean, Nationwide, Matched, Retrospective Cohort Study

Objectives: The present study was undertaken to investigate the relationship between acupuncture therapy and surgery rate. Design: Matched, retrospective cohort study. Materials and Methods: From nationwide health insurance data (2002-2013 cohort data published by the National Health Insurance Service of Korea), patients with new cases of knee osteoarthritis that occurred between January 1, 2004 and December 31, 2010 were analyzed. Patients were divided into an acupuncture group (AG) and a control group (CG), based on records of acupuncture therapy. Propensity scores were calculated by using gender, age, income level, and Charlson comorbidity index (CCI), with the groups matched at a ratio of 1:3 (AG:CG). The final analysis period was 2 years after the first acupuncture therapy for AG and 2 years after initial diagnosis for CG; surgery rates were compared between the two groups. Stratified analyses were performed based on age, gender, and income level; sensitivity analyses were performed based on the frequency and duration of acupuncture therapy. Results: Propensity score-matched AG and CG included 8,605 and 25,815 subjects, respectively. Post-matching surgery rates were 0.26 and 0.93% in AG and CG, respectively. For all age groups, AG showed a lower surgery rate than CG. In the analysis based on gender, the female group showed a significantly lower hazard ratio of 0.225. In analysis based on income level, the results of the entire group were significant, with the lower income group showing the lowest hazard ratio. In sensitivity analyses, AG tended to show a lower surgery rate than CG. Conclusions: The present study demonstrated that acupuncture therapy is associated with a low rate of surgery for knee osteoarthritis. Additional studies are needed to support this conclusion.

Incidence and Complication Rates for Total Hip Arthroplasty in Rheumatoid Arthritis: A Systematic Review and Meta-Analysis Across Four Decades

INTRODUCTION

Over the past several decades, management of rheumatoid arthritis (RA) has evolved significantly, but few studies have examined the real-world impact of these changes on orthopaedic surgery in patients with RA. This systematic review assessed total hip arthroplasty (THA) incidence and postoperative complication rates across the past four decades.

METHODS

This is a systematic literature review sourcing data on THA in patients with RA from the electronic databases MEDLINE, EMBASE, Scopus, and Cochrane between January 1, 1980 and December 31, 2019.

RESULTS

The search retrieved 1715 articles of which 44 were included for quantitative synthesis. The rate for THA decreased by almost 40% from 11/1000 patient years (PY) in the 2000s to 7/1000 PY in the 2010s, while the overall complication rate decreased from 9.9% in the 1990s to 5.3% in the 2010s. Throughout the duration of the study, THA incidence and overall complication rate decreased. However, not all individual complication rates decreased. For example, revision and periprosthetic fracture decreased, infection and aseptic loosening remained constant, and dislocation increased.

CONCLUSION

Medical management of patients with RA has reduced the need for THA, while postoperative medical and surgical management has improved some postoperative outcomes. Nevertheless, there remains room for further improvement to postoperative outcomes through RA-specific management.

Incidence of Femoral Component Malrotation Using Posterior Condylar Referencing in Total Knee Arthroplasty

Proper femoral component rotation in total knee arthroplasty (TKA) is important, given the prognostic impact of a poorly positioned component. The purpose of this observational study was to determine the incidence of femoral component malrotation using posterior condylar axis (PCA) referencing. A total of 100 knees in 92 patients with varus gonarthritis of the knee undergoing primary TKA using a standard medial parapatellar approach were evaluated intraoperatively. After distal femoral resection, the standard femoral sizing guide referencing the posterior condylar axis was used to set femoral component rotation. This was then compared with both the transepicondylar (TEA) and trochlear anteroposterior axes (TRAx). Disparites were recorded and corrected in line with the epicondylar axis. Rotational adjustment for addition of further external rotation was made in 13 (13.0%) cases. In seven cases, the medial pin sites were raised between 1 and 3 mm, and in six cases, the lateral pin site was lowered between 1 and 3 mm (based on risk of notching the femoral cortex). It is critical to not rely exclusively on the PCA to confirm rotational positioning of the femoral component as predicted by posterior condylar referencing guides. Intraoperative adjustment and confirmation using the TEA and TRAx occurred in 13% of primary TKA cases, which might have, otherwise, had a significant effect on the clinical outcome.

Gravity-Assisted Passive Flexion in Total Knee Arthroplasty Recovery

This study examined the use of gravity-assisted passive flexion (GAP-FLEX) for perioperative total knee arthroplasty (TKA) recovery. The main questions associated with this technique were: (1) Can GAP-FLEX improve patient recovery of range of motion after TKA? (2) Does GAP-FLEX reduce patient time and effort associated with therapy compared with continuous passive motion (CPM)? (3) Does GAP-FLEX reduce overall episodic care cost? A prospective, randomized multicenter study was conducted. Two senior surgeons used identical surgical approach, prosthesis, and postoperative management protocols. Patients consenting to the study were randomly assigned to either standard of care (CPM) or GAP-FLEX groups. Active flexion range of motion (ROM) was measured via goniometer with a primary endpoint established at 4 weeks after surgery. Secondary endpoints included pain and functional mobility. A total of 27 patients completed the study. Average ROM in the GAP-FLEX sample was 8.4° greater than the CPM sample (P=.009) at study endpoint. The GAP-FLEX patients achieved greater postoperative ROM within 2 days and maintained an improvement over CPM to study endpoint. Eighty-five percent (11 of 13) of GAP-FLEX patients achieved or surpassed their baseline ROM by study endpoint, compared with 50% (7 of 14) of CPM patients. These improvements occurred while requiring 90% less therapy time on device compared with the CPM patients. Patients did not report any statistically different pain levels but did exhibit higher functional mobility at endpoint (P=.026). [Orthopedics. 2020;43(5):e431-e437.].

A Modified Murine Calvarial Osteolysis Model Exposed to Ti Particles in Aseptic Loosening

Aim

To investigate the different effects on osteolysis between commercial pure Ti particles and TiAl6V4 particles obtained from prosthesis of patients with aseptic loosening.

Method

Scanning electron microscope, energy dispersive X-ray spectrometry, and X-ray diffraction were used for the size test, chemical composition test, and phase analysis of two kinds of Ti particles. Microcomputed tomography (micro-CT) and 3-dimensional reconstruction analysis were applied to analyze the bone loss quantitatively and radiologically. Hematoxylin-eosin (HE) staining and tartrate-resistant acid phosphatase (TRAP) staining were used to assess the histologic difference.

Result

TiAl6V4 particles were constituted by FeO, Al₄₅V₇, and Al₃Ti while pure Ti particles were constituted by Ti, Ti₃O, and C₄H₇NO₃. Similar particle size of nanoscale was detected of two Ti particles. A TiAl6V4 osteolysis model had more severe bone loss when scanned with micro-CT and assessed by quantitative analysis. TiAl6V4 also presented deeper and wider calvarial bone loss in HE staining and more activated osteoclasts in TRAP staining.

Conclusion

A mouse calvarial model is the most effective animal model for the primary in vivo research of aseptic loosening. Compared with commercial Ti particles, TiAl6V4 particles derived from prosthesis of an aseptic loosening patient had more severe bone loss and more activated osteoclast, which was more consistent with pathogenesis of aseptic loosening in vivo, had high success rate of establishment of a model, and was more desired in animal modeling.

Elevated Infection and Complication Rates in Patients Undergoing a Primary THA With a History of a PJI in a Prior Hip or Knee Arthroplasty: A Matched Cohort Study

BACKGROUND

There are little data on the outcomes of primary total hip arthroplasties (THAs) in patients with a prior surgically treated hip or knee periprosthetic joint injection (PJI). The goal of this study was to compare the risk of infection in this population with matched controls.

METHODS

We retrospectively reviewed 48 patients whom underwent 50 primary THAs from 2000 to 2014 with a history of a PJI in a total knee arthroplasty or contralateral THA. Thirteen patients (27%) were on chronic antibiotic suppression at the time of primary THA. Mean age was 67 years, and mean body mass index was 35 kg/m². Mean follow-up was 6 years. We 1:3 matched (age, sex, body mass index, cemented vs cementless femoral fixation, and surgical year) these cases to 150 primary THAs. Competing risk analysis, with death as the competing risk, was performed.

RESULTS

The cumulative incidence of PJI with death as a competing risk was 1.5-fold higher in the study cohort (2.0%) compared with matched controls (1.4%) (hazards ratio, 1.5; P = .75). The cumulative incidence of any infection with death as a competing risk was 2-fold higher in the study cohort (4.0%) compared with matched controls (2.1%) (hazards ratio, 2.0; P = .45). However, these were both statistically similar given the relatively small cohort. The overall complication rate, including infections and reoperations, was 17% in the study cohort.

CONCLUSION

Patients undergoing a clean primary THA with a history of a total knee arthroplasty or contralateral THA PJI in another joint have a 2% and 4% risk of PJI and any infection, respectively. Moreover, nearly 1 in 5 patients experience at least 1 complication.

Tibial alignment technique and its influence on clinical and functional outcomes following total knee arthroplasty

BACKGROUND

Restoration of neutral mechanical axis is thought to influence implant survival and function in Total Knee Arthroplasty (TKA). There is no consensus whether Intramedullary (IM) or Extramedullary (EM) tibial alignment technique is superior to achieve this outcome. Study aims to evaluate functional and radiological outcome of TKA using the EM and IM technique.

MATERIALS AND METHODS

A retrospective study of 400 primary TKA (314 patients) was performed. 200 knees were studied in each IM and EM group, which were matched. Functional assessment was performed using Oxford Knee Score (OKS) and Tibial component alignment measured in coronal and sagittal radiographs.

RESULTS

The average coronal and sagittal alignment of the tibial component in IM group was 89.16° and 88°, whereas in EM group, these were 88.1° and 88.5° respectively. The adjusted mean difference change in Pre and Post-operative OKS in IM group compared to EM group was 0.5 (p = 0.52). There was no statistically significant difference in the complications between the two groups. Subgroup analysis of patients with BMI >35 showed predictable coronal tibial alignment with IM technique with fewer outliers.

CONCLUSION

Intramedullary tibial alignment is associated with fewer outliers compared to the extramedullary technique particularly in patients with a BMI over 35.

Acute kidney injury after primary total hip arthroplasty: a risk multiplier for complication, mortality, and healthcare utilization

Objective

To assess whether acute kidney injury (AKI) is associated with more complications and higher healthcare utilization in people undergoing primary total hip arthroplasty (THA).

Methods

Using a retrospective cohort study design, we performed multivariable-adjusted logistic regression of the 1998–2014 US National Inpatient Sample data to assess the association of AKI with complications (infection, transfusion, revision, and mortality) and healthcare utilization (total hospital charges, discharge to a rehabilitation facility, length of hospital stay) post-THA. We calculated the odds ratio (OR) and 95% confidence intervals (CI).

Results

Adjusted for age, gender, race, income, underlying diagnosis, medical comorbidity, and the insurance payer, AKI in people who underwent primary THA was associated with significantly higher OR (95% CI) of (1) implant infection, 2.34 (95% CI, 1.87, 2.93); (2) transfusion, 2.46 (95% CI, 2.37, 2.56); (3) revision, 2.54 (95% CI, 2.16, 2.98); (4) death, 8.52 (95% CI, 7.47, 9.73); (5) total hospital charges above the median, 2.29 (95% CI, 1.99, 2.65); (6) discharge to a rehabilitation facility, 2.11 (95% CI, 2.02, 2.20); and (7) hospital stay > 3 days, 4.34 (95% CI, 4.16, 4.53).

Conclusion

Quality improvement initiatives with optimization of the peri-operative care to reduce AKI and subsequently AKI-associated complications and healthcare utilization are needed. Mechanisms of AKI-associated post-THA complications need further examination.

Effects of early virtual reality-based rehabilitation in patients with total knee arthroplasty: A randomized controlled trial

BACKGROUND

Virtual reality (VR)-based rehabilitation is a promising approach for improving recovery in many conditions to optimize functional results, enhancing the clinical and social benefits of surgery.

OBJECTIVE

To assess the efficacy of an early rehabilitation performed by the VR-based rehabilitation versus the traditional rehabilitation provided by physical therapists after primary total knee arthroplasty (TKA).

METHODS

In this randomized controlled clinical trial, 85 subjects met the inclusion criteria and were randomized 3 to 4 days after TKA to an inpatient VR-based rehabilitation and a traditional rehabilitation. Participants in both groups received 60 minutes/day sessions until discharge (around 10 days after surgery). The primary outcome was the pain intensity. The secondary outcomes were: the disability knee, the health related quality of life, the global perceived effect, the functional independent measure, the drugs assumption, the isometric strength of quadriceps and hamstrings, the flexion range of motion, and the ability to perform proprioception exercises. Outcomes were assessed at baseline (3-4 days after TKA) and at discharge.

RESULTS

VR-based or traditional rehabilitation, with 13% of dropout rate, shown no statistically significant pain reduction between groups (P = .2660) as well as in all other outcomes, whereas a statistically significant improvement was present in the global proprioception (P = .0020), in favor of the VR-based rehabilitation group.

CONCLUSIONS

VR-based rehabilitation is not superior to traditional rehabilitation in terms of pain relief, drugs assumptions and other functional outcomes but seems to improve the global proprioception for patients received TKA.

LEVEL OF EVIDENCE

Therapy, level 1b. CONSORT-compliant.

TRIAL REGISTRATION

http://www.clinicaltrials.gov, ClinicalTrials.gov, NCT02413996.

Cost-effectiveness of total knee replacement in addition to non-surgical treatment: a 2-year outcome from a randomised trial in secondary care in Denmark

OBJECTIVE

To assess the 24-month cost-effectiveness of total knee replacement (TKR) plus non-surgical treatment compared with non-surgical treatment with the option of later TKR if needed.

METHODS

100 adults with moderate-to-severe knee osteoarthritis found eligible for TKR by an orthopaedic surgeon in secondary care were randomised to TKR plus 12 weeks of supervised non-surgical treatment (exercise, education, diet, insoles and pain medication) or to supervised non-surgical treatment alone. Including quality-adjusted life years (QALYs) data from baseline, 3, 6, 12 and 24 months, effectiveness was measured as change at 24 months. Healthcare costs and transfer payments were derived from national registries. Incremental healthcare costs, and incremental cost-effectiveness ratios (ICERs) were calculated. A probabilistic sensitivity analysis was conducted and the probability of cost-effectiveness was estimated at the 22 665 Euros/QALY threshold defined by the National Institute for Health and Care Excellence.

RESULTS

TKR plus non-surgical treatment was more expensive (mean of 23 076 vs 14 514 Euros) but also more effective than non-surgical treatment (mean 24-month improvement in QALY of 0.195 vs 0.056). While cost-effective in the unadjusted scenario (ICER of 18 497 Euros/QALY), TKR plus non-surgical treatment was not cost-effective compared with non-surgical treatment with the option of later TKR if needed in the adjusted (age, sex and baseline values), base-case scenario (ICER of 32 611 Euros/QALY) with a probability of cost-effectiveness of 23.2%. Including deaths, TKR plus non-surgical treatment was still not cost-effective (ICERs of 46 277 to 64 208 Euros/QALY).

CONCLUSIONS

From a 24-month perspective, TKR plus non-surgical treatment does not appear to be cost-effective compared with non-surgical treatment with the option of later TKR if needed in patients with moderate-to-severe knee osteoarthritis and moderate intensity pain in secondary care in Denmark. Results were sensitive to changes, highlighting the need for further confirmatory research also assessing the long-term cost-effectiveness of TKR.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT01410409).

Preoperative valgus deformity has twice the risk of failure as compared to varus deformity after total knee arthroplasty

PURPOSE

The aim of this study was to assess whether preoperative valgus or varus deformity affected survivorship after total knee arthroplasty (TKA) and to quantify the risk factors for implant failure in a registry-based population.

METHODS

The Emilia-Romagna Registry of Prosthetic Orthopedic Implants was examined regarding TKAs performed on patients with a preoperative diagnosis of valgus or varus deformity. Demographics, implant characteristic and survivorships were investigated and compared. A total of 2327 TKA procedures performed from 2000 to 2016 were included in the study. Six hundred and forty primary TKAs with a diagnosis of valgus deformity were evaluated with a median follow-up of 3.3 years; 1687 primary TKAs with a diagnosis of varus deformity were evaluated with a median follow-up of 2.5 years.

RESULTS

Bi-compartmental, cemented posterior stabilised fixed-bearing implants were preferred. For both diagnoses, the implant survivorship rate was greater than 98% in the first year. However, the survival curve of the TKAs implanted for valgus deformity showed a greater slope in the first 3 years as compared to the survival curve of those implanted for varus deformity. Valgus deformity had a 2.1-fold higher risk for revision as compared with varus deformity. Infection was a major cause of implant failure in TKAs for varus deformity, 9/24 (37.5%), while its incidence was lower for valgus deformity, 1/21 (4.8%).

CONCLUSIONS

Preoperative valgus alignment showed a twofold risk of failure as compared to varus alignment after TKA. This should be considered in daily practice, and surgeons are called on to pay more attention when performing TKAs on such patients. Prospective randomised controlled trials are, therefore, necessary to better understand the role of preoperative coronal knee deformity in implant failure.

LEVEL OF EVIDENCE

Prognostic study, level III.

Patient-reported outcome measures (PROMs) after elective hip, knee and shoulder arthroplasty: protocol for a prospective cohort study

Background

The number of hip, knee and shoulder arthroplasties continues to rise worldwide. The Organization for Economic Cooperation and Development has launched an initiative (called PaRIS Initiative) for the systematic collection of Patient Reported Outcome Measures (PROMs) in patients undergoing elective hip and knee arthroplasty. The Rizzoli Orthopedic Institute (IOR) was selected as a pilot center for the launch of the Initiative in Italy given that IOR hosts the Registry of Orthopedic Prosthetic Implants (RIPO), a region-wide registry which collects joint implant data from all the hospitals in the Emilia-Romagna Region. In this specific geographic area information related to PROMs after joint replacement is unknown. This paper describes the protocol of a study (PaRIS-IOR) that aims to implement the collection of a set of PROMs within an existing implant registry in Italy. The study will also investigate the temporal trend of PROMs in relation to the type of prosthesis and the type of surgical intervention.

Methods

The PaRIS-IOR study is a prospective, single site, cohort study that consists of the administration of PROMs questionnaires to patients on the list for elective arthroplasty. The questionnaires will be administered to the study population within 30 days before surgery, and then at 6 and 12 months following surgery. The study population will consist of consecutive adult patients undergoing either hip, knee or shoulder arthroplasty. The collected data will be linked with those routinely collected by the RIPO in order to assess the temporal trend of PROMs in relation to the type of prosthesis and the type of surgical intervention.

Discussion

The PaRIS-IOR study could have important implications in targeting the factors influencing functional outcomes and quality of life reported by patients after hip, knee and shoulder arthroplasty, and will also represent the first systematic collection of PROMs related to arthroplasty in Italy.

Trial registration

Protocol version (1.0) and trial registration data are available on the platform www.clinicaltrial.gov with the identifier NCT03790267, first posted on December 31, 2018.

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.

Increased Orthopedic Specialization Lowers Costs and Improves Outcomes in Total Joint Arthroplasty

BACKGROUND

Total joint arthroplasty (TJA) volumes have risen in the past decade, resulting in increased national spending. Prior studies indicate that TJA performed at higher-volume hospitals result in better patient outcomes at lower costs. The purpose of this study is to determine whether increased orthopedic specialization has similar effects.

METHODS

Centers for Medicare and Medicaid Services Inpatient Charge Data queries identified 2677 hospitals that performed TJA in 2015. Hospitals were assigned an orthopedic specialization ratio (OSR), defined as the ratio of musculoskeletal discharges to total discharges. Average covered charges (ACC), average total payments, and average Medicare payments (AMP) of TJA were extracted. TJA-specific, risk-adjusted complication and readmission scores were obtained from the Centers for Medicare and Medicaid Services Hospital Compare database. Comparisons between orthopedic specialty hospitals and nonspecialty hospitals performing TJA were made with Student t-tests. Regression models analyzed the relationship between OSR, volume and cost, payments, readmission rate score, and complication rate score.

RESULTS

Orthopedic specialty hospitals had lower ACC, average total payments, AMP, readmission, and complication scores than nonspecialty hospitals (all P < .001). Regression models showed that as the OSR increased from 0 to 1.0, ACC decreased by $19,242.83 and AMP decreased by $2310.75 (P < .001). Readmission score decreased by 0.349 and complication score decreased by 0.346 (P < .001) when controlling for volume as the OSR increased from 0 to 1.

CONCLUSION

Hospitals with increased OSR appear to perform TJA for Medicare patients at a lower cost with lower complication and readmission risk. It may be beneficial to consider the OSR when determining the ideal settings for TJA.