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

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.

Effects of Osteoarthritis Pain and Concurrent Insomnia and Depression on Health Care Use in a Primary Care Population of Older Adults

OBJECTIVE

To examine independent and combined effects of pain with concurrent insomnia and depression symptoms on the use of health care services in older adults with osteoarthritis (OA).

METHODS

Patients were Group Health Cooperative (GHC) patients with a primary diagnosis of OA (n = 2,976). We used survey data on pain (Graded Chronic Pain Scale), insomnia (Insomnia Severity Index), and depression (Patient Health Questionnaire-8), and health care use extracted from GHC electronic health records (office visits, length of stay, outpatient and inpatient costs, and hip or knee replacement) for 3 years after the survey. Negative binomial, logistic, and generalized linear models were used to assess predictors of health care use.

RESULTS

Approximately 34% and 29% of patients displayed at least subclinical insomnia and at least subclinical depression symptoms, respectively, in addition to moderate-to-severe pain. Pain had the greatest independent effects on increasing all types of health care use, followed by depression (moderate effects) on increased office visits, length of stay, outpatient and inpatient costs, and insomnia (mild effects) on decreased length of stay. No synergistic effects of the 3 symptoms on use of health care services were observed. The combined effects of pain plus insomnia and pain plus depression were significant for all types of health care use and increased greatly with increasing severity of insomnia and depression, except for hip/knee replacement.

CONCLUSION

Pain is the main driver for health care use in patients with OA. In addition to pain, insomnia plus depression jointly increased diverse types of health care use, and these combined effects increased greatly with increasing severity of insomnia and depression. These findings indicate the important role that concurrent symptomatic conditions may play in increasing use of health care services.

Rates of Total Joint Replacement in the United States: Future Projections to 2020–2040 Using the National Inpatient Sample

Objective.

To project future total hip and knee joint arthroplasty (THA, TKA) use in the United States to 2040.

Methods.

We used the 2000–2014 US National Inpatient Sample (NIS) combined with Census Bureau data to develop projections for primary THA and TKA from 2020 to 2040 using polynomial regression to account for the nonlinearity and interactions between the variables, assuming the underlying distribution of the number of THA/TKA to be Poisson distributed. We performed sensitivity analyses using a negative binomial regression to account for overdispersion.

Results.

Predicted total annual counts (95% prediction intervals) for THA in the United States by 2020, 2025, 2030, and 2040 are (in thousands): 498 (475, 523), 652 (610, 696), 850 (781, 925), and 1429 (1265, 1615), respectively. For primary TKA, predicted total annual counts for 2020, 2025, 2030, and 2040 are (in thousands): 1065 (937, 1211), 1272 (1200, 1710), 1921 (1530, 2410), and 3416 (2459, 4745), respectively. Compared to the available 2014 NIS numbers, the percent increases in projected total annual US use for primary THA and TKA in 2020, 2025, 2030, and 2040 are as follows: primary THA, by 34%, 75%, 129%, and 284%; and primary TKA, 56%, 110%, 182%, and 401%, respectively. Primary THA and TKA use is projected to increase for both females and males, in all age groups.

Conclusion.

Significant increases in use of THA and TKA are expected in the United States in the future, if the current trend continues. The increased use is evident across age groups in both females and males. A policy change may be needed to meet increased demand.

The influence of pre- and perioperative administration of gabapentin on pain 3-4 years after total knee arthroplasty

BACKGROUND AND AIMS

Approximately 20% of patients having total knee arthroplasty (TKA) will experience chronic postoperative pain. Recently, preoperative pain facilitation has been associated with chronic pain after TKA, and gabapentin has been shown to decrease pain facilitation. The current study is a secondary follow-up of a primary RCT investigating the effect of gabapentin on acute postoperative pain after TKA and exploring the effect of pre- and perioperative administration of gabapentin on chronic postoperative pain and psychological state 3-4 years after TKA.

METHODS

Patients scheduled for TKA were randomized to either gabapentin 1,300 mg/day, gabapentin 900 mg/day, or placebo daily from 2-h before and 6 days after operation. Pre- and 3-4 years postoperatively pain scores related to pain while walking, at rest, when flexing the hip or the knee were collected. At the same time, the pain catastrophizing scale (PCS) and hospital anxiety and depression scale subscales for anxiety (HADS-A) and depression (HADS-D) were collected.

RESULTS

Lower postoperative pain while walking, flexing the hip, and at rest were found compared with preoperative scores (p<0.03), but these were not associated with gabapentin treatment (p>0.19). Significantly lower postoperative PCS and HADS-A scores were seen compared with preoperative scores (p<0.001), but these were not associated with gabapentin treatment (p>0.55).

CONCLUSIONS

The current study found that pre- and perioperative administrations of gabapentin do not influence the pain or psychological state 3-4 years after TKA.

IMPLICATIONS

The current study does not support that short-term pre- and perioperative use of gabapentin can reduce the development of chronic postoperative pain after TKA.

Post-acute Transitional Journey: Caring for Orthopedic Surgery Patients in the United States

As the geriatric population in the United States continues to age, there will be an increased demand for total hip and total knee arthroplasties (THAs and TKAs). Older patients tend to have more comorbidities and poorer health, and will require post-acute care (PAC) following discharge. The most utilized PAC facilities following THA and TKA are skilled nursing facilities (SNFs), in-patient rehabilitation facilities (IRFs), and home with home health care (HHC). Coordination of care between hospitals and PACs, including the complete transfer of patient information, continues to be a challenge which impacts the quality of care provided by the PACs. The increased demand of hospital resources and PACs by the geriatric population necessitates an improvement in this transition of care process. This review aims to examine the transition of care process currently utilized in the United States for orthopedic surgery patients, and discuss methods for improvement. Employing these approaches will play a key role in improving patient outcomes, decreasing preventable hospital readmissions, and reducing mortality following THA and TKA. The extensive nature of this topic and the ramification of different types of healthcare systems in different countries were the determinant factors limiting our work.

Association Between Knee Malalignment and Ankle Degeneration in Patients With End-Stage Knee Osteoarthritis

BACKGROUND

The association between knee malalignment and ankle degeneration has not been well established. This study aimed at determining whether knee malalignment and compensatory ankle morphology to knee malalignment are associated with the development and progression of ankle osteoarthritis (OA) in patients with end-stage knee OA.

METHODS

We retrospectively reviewed 96 patients (106 knees) who underwent total knee arthroplasty. The progression of ankle OA, knee alignment, and ankle morphology were evaluated based on digital radiographs. Alignment deformity of the lower extremity was evaluated with hip-knee-ankle angle and medial proximal tibial angle (MPTA). Ankle morphology was evaluated by the lateral distal tibial angle, talar tilt, tibial plafond inclination angle, and ankle joint line orientation angle.

RESULTS

The incidence of radiological ankle OA was observed in 39 of 106 cases. The MPTA (odds ratio = 0.72, P = .0009) and hip-knee-ankle angle (odds ratio = 1.13, P = .0169) were significantly associated with ankle OA. Among patients with tibial varus deformity, 26 of 49 had ankle OA. Among patients with neutral tibial alignment, 13 of 57 had radiological findings of ankle OA. MPTA was the only parameter associated with the progression of ankle OA. No association was observed between compensatory change in ankle morphology and the severity of ankle OA.

CONCLUSION

Tibial varus deformity is associated with the development and progression of ankle OA; however, it is unclear whether it causes ankle OA. Due to the high incidence of ankle OA in total knee arthroplasty patients, it is reasonable to consider routine evaluation of the ankle.

Characterizing Patient Preferences Surrounding Total Knee Arthroplasty

Background:

Episode-based bundled payments for total knee arthroplasty emphasize cost-effective patient-centered care. Understanding patients’ perceptions of components of the total knee arthroplasty care episode is critical to achieving this care. This study investigated patient preferences for components of the total knee arthroplasty care episode.

Methods:

Best-worst scaling was used to analyze patient preferences for components of the total knee arthroplasty care episode. Participants were selected from patients presenting to 2 orthopaedic clinics with chronic knee pain. They were presented with descriptions of 17 attributes before completing a best-worst scaling exercise. Attribute importance was determined using hierarchical Bayesian estimation. Latent class analysis was used to evaluate varying preference profiles.

Results:

One hundred and seventy-four patients completed the survey, and 117 patients (67%) were female. The mean age was 62.71 years. Participants placed the highest value on surgeon factors, including level of experience, satisfaction rating, and complication rates. Latent class analysis provided a 4-segment model of the population.

Conclusions:

This study demonstrated differences in patient preferences for the components of a total knee arthroplasty care episode and characterized distinct preference profiles among patient subsets. Stakeholders can use this information to focus efforts and policy on high-value components and to potentially create customized bundles guided by preference profiles.

Clinical Relevance:

This study is clinically relevant because the patient preferences identified here may help providers to design customized bundles for total knee arthroplasty care.

Orthopedic Surgery Among Patients With Rheumatoid Arthritis: A Population-Based Study to Identify Risk Factors, Sex Differences, and Time Trends

OBJECTIVE

To identify risk factors for large-joint surgery (LJS) versus small-joint surgery (SJS) in rheumatoid arthritis (RA) and evaluate trends in surgery rates over time.

METHODS

A retrospective medical record review of all orthopedic surgeries following first fulfillment of the 1987 American College of Rheumatology criteria for adult-onset RA among residents of Olmsted County, Minnesota between 1980 and 2013 was performed. Risk factors were examined using Cox models adjusted for age, sex, and calendar year of RA incidence. Trends in incidence of joint surgeries were examined using Poisson regression models.

RESULTS

A total of 1,077 patients with RA (mean age 56 years, 69% female, 66% seropositive for rheumatoid factor [RF] and anti-cyclic citrullinated peptide [anti-CCP] antibodies) were followed for a median of 10.7 years, during which 112 patients (90 women) underwent at least 1 SJS and 204 (141 women) underwent at least 1 LJS. Risk factors included advanced age, and RF and anti-CCP antibody positivity for both SJS and LJS, and body mass index ≥30 kg/m² for LJS. Risk factors for SJS and LJS at any time during followup included the presence of radiographic erosions, large-joint swelling, and methotrexate use. SJS rates decreased by calendar year of incidence (hazard ratio 0.53, P = 0.001), with significant decline in the rates of SJS after 1995. The cumulative incidence of SJS was higher in women than men (P = 0.008).

CONCLUSION

In recent years, there has been a significant decline in the rates of SJS but not LJS in patients with RA. The incidence of SJS is higher among women. Traditional RA risk factors are strong predictors for SJS and LJS. Increasing age and obesity are predictive of LJS.

Projected Volume of Primary Total Joint Arthroplasty in the U.S., 2014 to 2030

BACKGROUND

The volume of primary total joint arthroplasty (TJA) procedures has risen in recent decades. However, recent procedure growth has not been at previously projected exponential rates. To anticipate the future expense of TJA, updated models are necessary to predict TJA volume in the U.S.

METHODS

Retrospective review using the National Inpatient Sample, a representative sample of all hospital discharges within the U.S., was employed to determine the volume of primary TJA procedures performed from 2000 to 2014. Over 116 million discharge records were reviewed and weighted to determine the simulated annual TJA volume. The annual incidence rate of each procedure was determined by combining procedure volume with annual census data among the overall population and in subpopulations defined by sex and age. Linear and Poisson regression analyses were performed to determine the projected future volume of TJA procedures. Subanalysis with linear regression estimates based on 2000 to 2008 and 2008 to 2014 growth rates was performed.

RESULTS

On the basis of 2000-to-2014 data, primary total hip arthroplasty (THA) is projected to grow 71%, to 635,000 procedures, by 2030 and primary total knee arthroplasty (TKA) is projected to grow 85%, to 1.26 million procedures, by 2030. However, TKA procedure growth rate has been slowing over recent years, and models based on 2008-to-2014 data projected growth to only approximately 935,000 procedures by 2030.

CONCLUSIONS

Previously anticipated exponential TJA growth is inconsistent with the most recent trends. An updated projection based on 2000-to-2014 data is provided to project the growth of primary TJA procedures to the year 2030. These data will help guide health-care economic policy and allocation of future resources in order to optimize the delivery of patient care.

Total knee replacement and non-surgical treatment of knee osteoarthritis: 2-year outcome from two parallel randomized controlled trials

OBJECTIVES

To compare 2-year outcomes of total knee replacement (TKR) followed by non-surgical treatment to that of non-surgical treatment alone and outcomes of the same non-surgical treatment to that of written advice.

DESIGN

In two randomized trials, 200 (mean age 66) adults with moderate to severe knee osteoarthritis (OA), 100 eligible for TKR and 100 not eligible for TKR, were randomized to TKR followed by non-surgical treatment, non-surgical treatment alone, or written advice. Non-surgical treatment consisted of 12 weeks of supervised exercise, education, dietary advice, use of insoles, and pain medication. The primary outcome was the mean score of the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales, covering pain, symptoms, activities of daily living (ADL), and quality of life (QOL).

RESULTS

Patients randomized to TKR had greater improvements than patients randomized to non-surgical treatment alone (difference of 18.3 points (95% CI; 11.3 to 25.3)), who in turn improved more than patients randomized to written advice (difference of 7.0 points (95% CI; 0.4 to 13.5)). Among patients eligible for TKR, 16 (32%) from the non-surgical group underwent TKR during 2 years and among those initially ineligible, seven patients (14%) from the non-surgical group and ten (20%) from the written advice group underwent TKR.

CONCLUSIONS

TKR followed by non-surgical treatment is more effective on pain and function than non-surgical treatment alone, which in turn is more effective than written advice. Two out of three patients with moderate to severe knee OA eligible for TKR delayed surgery for at least 2 years following non-surgical treatment.

TRIAL REGISTRATION

ClinicalTrials.gov numbers NCT01410409 and NCT01535001.

The projected burden of complex surgical site infections following hip and knee arthroplasties in adults in the United States, 2020 through 2030

BACKGROUND

As the US population ages, the number of hip and knee arthroplasties is expected to increase. Because surgical site infections (SSIs) following these procedures contribute substantial morbidity, mortality, and costs, we projected SSIs expected to occur from 2020 through 2030.

METHODS

We used a stochastic Poisson process to project the number of primary and revision arthroplasties and SSIs. Primary arthroplasty rates were calculated using annual estimates of hip and knee arthroplasty stratified by age and gender from the 2012-2014 Nationwide Inpatient Sample and standardized by census population data. Revision rates, dependent on time from primary procedure, were obtained from published literature and were uniformly applied for all ages and genders. Stratified complex SSI rates for arthroplasties were obtained from 2012-2015 National Healthcare Safety Network data. To evaluate the possible impact of prevention measures, we recalculated the projections with an SSI rate reduced by 30%, the national target established by the US Department of Health and Human Services (HHS).

RESULTS

Without a reduction in SSI rates, we projected an increase in complex SSIs following hip and knee arthroplasty of 14% between 2020 and 2030. We projected a total burden of 77,653 SSIs; however, meeting the 30% rate reduction could prevent 23,297 of these SSIs.

CONCLUSIONS

Given current SSI rates, we project that complex SSI burden for primary and revision arthroplasty may increase due to an aging population. Reducing the SSI rate to the national HHS target could prevent 23,000 SSIs and reduce subsequent morbidity, mortality, and Medicare costs.

Early death following revision total hip arthroplasty

INTRODUCTION

The frequency of primary total hip arthroplasty procedures is increasing, with a subsequent rise in revision procedures. This study aims to describe timing and surgical mortality associated with revision total hip arthroplasty (THA) compared to those on the waiting list.

METHODS

All patients from a single institution who underwent revision total hip arthroplasty or were added to the waiting list for the same procedure between 2003 and 2013 were recorded. Mortality rates were calculated at 30 and 90 days following surgery or addition to the waiting list.

RESULTS

561 patients were available for the survivorship analysis in the surgical group. Following exclusion, 901 and 484 patients were available for the 30 and the 90-day analysis in the revision THA waiting list group. 30- and 90-day mortality rates were significantly greater for the revision THA group compared to the waiting list group (excess surgical mortality at 30 days = 0.357%, p = 0.037; odds ratio of 5.22, excess surgical mortality at 90 days = 0.863%, p = 0.045).

CONCLUSIONS

Revision total hip arthroplasty is associated with a significant excess surgical mortality rate until 90 days post-operation when compared to the waiting list population. We would encourage other authors with access to larger samples to use our method to quantify excess mortality after both primary and revision arthroplasty procedures.

Length of stay and inpatient mortality trends in primary and revision total joint arthroplasty in the United States, 2000-2014

Retrospective review of the National Inpatient Sample was performed. LOS and IHM were assessed among TJA patients and assessed by comorbidity status. LOS among TJA patients decreased from 4.31 to 5.87 days to 2.83-4.49 days. Relative risk for prolonged LOS among high comorbidity patients ranged from 3.01-5.62. IHM per 1,000 was 5.1 for revision THA, 1.8 for revision TKA, 1.1 for primary THA, and 0.4 for primary TKA. Relative risk for IHM in high comorbidity patients ranged from 443.9-780.9 (p < 0.0001). LOS and IHM decreased significantly across all TJA procedures. LOS and IHM among the highest comorbidity groups are unacceptably high.

Impact of surgical case order on peri-operative outcomes for total joint arthroplasty

INTRODUCTION

There is growing support in the literatures that peri-operative outcomes are adversely affected by surgical case order in some certain surgical procedures. This study aimed to examine if similar phenomenon is also shared in total joint arthroplasty (TJA).

METHODS

A total of 6548 joints (5183 patients) treated with primary TJA by a total of five surgeons at our institution from December 2011 to December 2015 were retrospectively reviewed in this study. Demographic data, operative duration, blood loss, peri-operative adverse events, medical cost, and length of hospital stay were collected and analyzed. Logistic regression was used to determine risk factors for adverse events.

RESULTS

Of the 6548 cases in this cohort, 1643 TJAs were classified as first round cases, 1744 TJAs were second round cases, 1600 TJAs were third round cases, and 1561 TJAs were fourth or later round cases. Mean operating time was shorter in the intermediate cases (45.0 vs. 41.0 vs. 41.8 vs. 54.1 min, P < 0.01). Peri-operative arthroplastic adverse events were increased in later surgical cases (2.07% vs. 2.18% vs. 3.06% vs. 4.87%, P < 0.01). Later case order (OR = 1.40 [95% CI: 1.22-1.61], P < 0.01) was a significant risk factor of arthroplastic adverse events. Patients undergoing TJA later in the day were more likely to have longer length of stay and higher cost than earlier cases. Peri-operative systemic complications and blood loss did not significantly differ between groups.

CONCLUSION

Surgical case order is an independent risk factor for arthroplastic adverse events in TJA. TJA procedures performed later in the day have a higher risk for arthroplastic adverse events, but not for systematic adverse events. Significantly increased operative time, higher cost, and longer LOS were noted for fourth or later TJA cases. Data in our study reveals that performing more than three TJAs within a single day may imply compromised outcomes.

Continuing versus discontinuing antiplatelet drugs, vasodilators, and/or cerebral ameliorators on perioperative total blood loss in total knee arthroplasty without pneumatic tourniquet

Background

Although studies have supported the utility of perioperative continuation of antiplatelet drugs, vasodilators, and cerebral ameliorators in most procedures, no study compared total volume of blood loss after total knee arthroplasty (TKA) in patients continuing and discontinuing these drugs.

Methods

We retrospectively reviewed 266 consecutive patients undergoing TKA, and included 67 patients (25.2%) taking antiplatelet drugs, vasodilators, or cerebral ameliorators in this study. All TKAs were performed without a pneumatic tourniquet. The primary outcome was perioperative total blood loss calculated from blood volume and change in hemoglobin. As subgroup analysis, we compared perioperative total blood loss in patients taking antiplatelet drugs.

Results

There was no significant difference between the continuing group (n = 38) and discontinuing group (n = 29) in terms of the perioperative total blood loss (1025 ± 364 vs 1151 ± 327 mL, respectively; mean difference 126 mL; 95% confidence interval -45 to 298 mL; P = .15). No major bleeding or thrombotic events occurred in either group until postoperative 3-month follow-up. In patients taking antiplatelet drugs (n = 51), no significant difference was observed in the total blood loss between the continuing group (n = 30) and discontinuing group (n = 21) (1056 ± 287 vs 1151 ± 305 mL, respectively; mean difference 95 mL; 95% confidence interval -75 to 264 mL; P = .27).

Conclusions

No significant differences in terms of perioperative total blood loss were observed between patients continuing and discontinuing study drugs. Continuing these drugs may be preferable in the perioperative period of TKA.

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

Background

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

Objectives

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

Design

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

Results

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

Conclusion

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

Future work

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

Funding

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

Impact of total knee replacement practice: cost effectiveness analysis of data from the Osteoarthritis Initiative

Objectives To evaluate the impact of total knee replacement on quality of life in people with knee osteoarthritis and to estimate associated differences in lifetime costs and quality adjusted life years (QALYs) according to use by level of symptoms.Design Marginal structural modeling and cost effectiveness analysis based on lifetime predictions for total knee replacement and death from population based cohort data.Setting Data from two studies-Osteoarthritis Initiative (OAI) and the Multicenter Osteoarthritis Study (MOST)-within the US health system.Participants 4498 participants with or at high risk for knee osteoarthritis aged 45-79 from the OAI with no previous knee replacement (confirmed by baseline radiography) followed up for nine years. Validation cohort comprised 2907 patients from MOST with two year follow-up.Intervention Scenarios ranging from current practice, defined as total knee replacement practice as performed in the OAI (with procedural rates estimated by a prediction model), to practice limited to patients with severe symptoms to no surgery.Main outcome measures Generic (SF-12) and osteoarthritis specific quality of life measured over 96 months, model based QALYs, costs, and incremental cost effectiveness ratios over a lifetime horizon.Results In the OAI, total knee replacement showed improvements in quality of life with small absolute changes when averaged across levels of confounding variables: 1.70 (95% uncertainty interval 0.26 to 3.57) for SF-12 physical component summary (PCS); -10.69 (-13.39 to -8.01) for Western Ontario and McMaster Universities arthritis index (WOMAC); and 9.16 (6.35 to 12.49) for knee injury and osteoarthritis outcome score (KOOS) quality of life subscale. These improvements became larger with decreasing functional status at baseline. Provision of total knee replacement to patients with SF-12 PCS scores <35 was the optimal scenario given a cost effectiveness threshold of $200 000/QALY, with cost savings of $6974 ($5789 to $8269) and a minimal loss of 0.008 (-0.056 to 0.043) QALYs compared with current practice. These findings were reproduced among patients with knee osteoarthritis from the MOST cohort and were robust against various scenarios including increased rates of total knee replacement and mortality and inclusion of non-healthcare costs but were sensitive to increased deterioration in quality of life without surgery. In a threshold analysis, total knee replacement would become cost effective in patients with SF-12 PCS scores ≤40 if the associated hospital admission costs fell below $14 000 given a cost effectiveness threshold of $200 000/QALY.Conclusion Current practice of total knee replacement as performed in a recent US cohort of patients with knee osteoarthritis had minimal effects on quality of life and QALYs at the group level. If the procedure were restricted to more severely affected patients, its effectiveness would rise, with practice becoming economically more attractive than its current use.

Cytokine and neuropeptide levels are associated with pain relief in patients with chronically painful total knee arthroplasty: a pilot study

Background

There are few studies with an assessment of the levels of cytokines or neuropeptides as correlates of pain and pain relief in patients with painful joint diseases. Our objective was to assess whether improvements from baseline to 2-months in serum cytokine, chemokine and substance P levels were associated with clinically meaningful pain relief at 2-months post-injection in patients with painful total knee arthroplasty (TKA).

Methods

Using data from randomized trial of 60 TKAs, we assessed the association of change in cytokine/chemokine/Substance P levels with primary study outcome, clinically important improvement in Western Ontario McMaster Osteoarthritis Index (WOMAC) pain subscale at 2-months post-injection using Student’s t-tests and Spearman’s correlation coefficient (non-parametric). Patients were categorized as pain responders (20-point reduction or more on 0-100 WOMAC pain) vs. pain non-responders. Sensitivity analysis used 0–10 daytime pain numeric rating scale (NRS) instead of WOMAC pain subscale.

Results

In a pilot study, compared to non-responders (n = 23) on WOMAC pain scale at 2-months, pain responders (n = 12) had significantly greater increase in serum levels of IL-7, IL-10, IL-12, eotaxin, interferon gamma and TNF-α from baseline to 2-months post-injection (p < 0.05 for all). Change in several cytokine/chemokine and substance P levels from pre-injection to 2-month follow-up correlated significantly with change in WOMAC pain with correlation coefficients ranging −0.37 to −0.51: IL-2, IL-7, IL-8, IL-9, IL-16, IL-12p, GCSF, IFN gamma, IP-10, MCP, MIP1b, TNF-α and VEGF (n = 35). Sensitivity analysis showed that substance P decreased significantly more from baseline to 2-months in the pain responders (0.54 ± 0.53; n = 10) than in the pain non-responders (0.48 ± 1.18; n = 9; p = 0.023) and that this change in serum substance P correlated significantly with change in daytime NRS pain, correlation coefficient was 0.53 (p = 0.021; n = 19). Findings should be interpreted with caution, since cytokine analyses were performed for a sub-group of the entire trial population.

Conclusion

Serum cytokine, chemokine and Substance P levels correlated with pain response in patients with painful TKA after an intra-articular injection in a randomized trial.

Adductor canal block versus femoral nerve block for total knee arthroplasty: a meta-analysis of randomized controlled trials

Femoral nerve blocks (FNB) can provide effective pain relief but result in quadriceps weakness with increased risk of falls following total knee arthroplasty (TKA). Adductor canal block (ACB) is a relatively new alternative providing pure sensory blockade with minimal effect on quadriceps strength. The meta-analysis was designed to evaluate whether ACB exhibited better outcomes with respect to quadriceps strength, pain control, ambulation ability, and complications. PubMed, Embase, Web of Science, Wan Fang, China National Knowledge Internet (CNKI) and the Cochrane Database were searched for RCTs comparing ACB with FNB after TKAs. Of 309 citations identified by our search strategy, 12 RCTs met the inclusion criteria. Compared to FNB, quadriceps maximum voluntary isometric contraction (MVIC) was significantly higher for ACB, which was consistent with the results regarding quadriceps strength assessed with manual muscle strength scale. Moreover, ACB had significantly higher risk of falling versus FNB. At any follow-up time, ACB was not inferior to FNB regarding pain control or opioid consumption, and showed better range of motion in comparison with FNB. ACB is superior to the FNB regarding sparing of quadriceps strength and faster knee function recovery. It provides pain relief and opioid consumption comparable to FNB and is associated with decreased risk of falls.

The Importance of Bone Mineral Density in Hip Arthroplasty: Results of a Survey Asking Orthopaedic Surgeons about Their Opinions and Attitudes Concerning Osteoporosis and Hip Arthroplasty

Objective. In patients scheduled to undergo total joint arthroplasty of the hip, the bone quality around the joint affects the safety of prosthetic implantation. Bone strength is clinically assessed by measuring bone mineral density (BMD); therefore we asked if BMD is important to orthopaedic surgeons performing hip arthroplasty. Methods. In a 14-question survey, we asked about treatment patterns with respect to BMD, osteoporosis work-up, and treatment for patients with low BMD scheduled to undergo hip arthroplasty. Results. 72% of all asked orthopaedics reported to use cementless implants as a standard in hip arthroplasty. Over 60% reported that low BMD is a reason to reconsider operation strategies, but only 4% performed BMD measurement preoperatively. 26% would change their treatment strategy in case of a BMD (T-Score) between −1.5 and −2 and 40% in case of a T-score between −2 and −2.5, and 29% would change their intraoperative strategy if a T-score smaller than −2.5 was measured. Conclusion. The majority of orthopaedic surgeons who responded to the survey reported that they do not perform routine measurement of BMD before arthroplasty. However, most surgeons commented that low bone mineral density will influence their surgical plan and the implant design.

Impact of atrial fibrillation on postoperative outcomes after total knee arthroplasty-A retrospective study

BACKGROUND

Total knee arthroplasty (TKA) is primarily preformed among the elderly population who is commonly affected by cardiovascular and cerebrovascular diseases. Atrial fibrillation (AF) is a very common heart disease and its prevalence increases significantly with age. Therefore, we decided to evaluate the outcomes of patients with AF following TKA and analyze the risk factors of AF patients who underwent postoperative complication.

METHODS

We designed a retrospective cohort study using data from three institutions in China. We evaluated a total of 453 AF patients who received primary TKA and 453 matched control patients. Comparisons of specific parameters between AF and non-AF cohorts were performed.

RESULTS

Our results demonstrated that AF patients had significantly higher odds of more intraoperative bleeding, periprosthetic joint infection (PJI), post-operative cerebral stroke (POCS), post-operative cardiovascular events (POCE) and worse SF-36 physical component score and mental score at mean 24-month after surgery, but had no increased incidence of post-operative gastrointestinal events, DVT and PE in comparison to patients without AF than those without AF disease. Additionally, multivariate logistic regression analysis was used to identify risk factors of patients who underwent severe complication. Smoking, diabetes mellitus and persistent AF were common risk factors of PJI, POCS, and POCE. Heart rate＞70/min and absence of Beta blocker use were common risk factors of POCS and POCE. Absence of LMWH bridging was risk factor of POCS. BMI >25 kg/m2 and hypertension were risk factors of POCE.

CONCLUSIONS

These findings should be taken into consideration when discussing the expected outcomes of AF patients after TKA. AF disease impaired SF-36 physical component score (PCS) and mental component score (MCS) of patient after TKA.

Total Joint Arthroplasty in a Stand-alone Ambulatory Surgical Center: Short-term Outcomes

For decades, the average hospital stay following total joint arthroplasty (TJA) has been getting shorter. The historical standard was several weeks of hospitalization, yet improvements in perioperative care have reduced the average length of stay to a few days. Medicare recognizes a 3-day inpatient stay as the standard of care following hip or knee replacement. Yet continued advances in minimally invasive surgical techniques, short-acting general anesthetics, long-acting local anesthetics, and blood loss management have further improved the safety and recovery for TJA procedures. Thus, further reductions in postoperative hospitalization have been implemented around the country, with surgeons reporting successful same-day protocols, as defined by hospitalization discharge on the day of surgery. Although these studies have presented results of same-day TJA in the hospital setting, this study is the first to report on the perioperative adverse events and early outcomes of 51 consecutive TJA procedures performed in a stand-alone ambulatory surgical center (ASC). The ASC offers an ideal setting to perform such procedures in the properly selected patient population, obviating any form of postoperative hospitalization. Although 16 (31.4%) of 51 patients reported minor adverse events in the postanesthesia care unit, specifically nausea and/or pain, early intervention permitted 50 (98.0%) of 51 patients to be discharged home, on average 176 minutes after surgery, with 1 patient discharged to a rehabilitation facility as arranged prior to surgery. There were no major adverse events in the 90-day perioperative period, and although 1 (2.0%) patient was hospitalized for persistent incisional drainage, none required admission for pain. This study examines the strict eligibility criteria and perioperative analgesia protocols that permit successful outpatient TJA. [Orthopedics. 2016; 39(4):223-228.].

The use of gabapentin in the management of postoperative pain after total knee arthroplasty: A PRISMA-compliant meta-analysis of randomized controlled trials

Pain management after total knee arthroplasty (TKA) varies and has been widely studied in recent years. Some randomized controlled studies have carried out to evaluate the effects of gabapentin on pain relief after TKA. However, no solid result was made about it. The purpose of this Meta-Analysis of Randomized Controlled Trials (RCTs) was to estimate the overall effect of pain control of gabapentin versus placebo after a TKA. An electronic-based search using the following databases: PubMed, EMBASE, Ovid MEDLINE, ClinicalTrials.gov, and Cochrane Central Register of Controlled Trial from 1966 to June 2015. RCTs involving gabapentin and placebo for total knee arthroplasty were included. The meta-analysis was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Six trials with 859 participants met the inclusion criteria. The primary endpoint was cumulative narcotic consumption and the visual analog scale scores at 12 hours, 24 hours, and 48 hours, postoperatively. The knee flexion degree and treatment side effects were also compiled to evaluate the safety of gabapentin. After testing for the heterogeneity and publication bias among studies, data were aggregated for random-effects modeling when necessary. There was a significant decrease in morphine consumption at 12 hours (MD = -4.69, 95% CI: -7.18 to -2.21, P = 0.0002), 24 hours (MD = -5.30, 95% CI: -9.94 to -0.66, P = 0.03), and 48 hours (MD = -17.80, 95% CI: -31.95 to -3.64, P = 0.01), respectively. Compared with the control group, the rate of pruritus was less in the gabapentin group (RR 0.20, 95% CI 0.10 to 0.38, P = 0.00). In summary, the administration of gabapentin was effective in decreasing postoperative narcotic consumption and the incidence of pruritus. There was a high risk of selection bias and a higher heterogeneity of knee flexion range in this analysis. More high-quality large randomized controlled trials with long follow-up period are necessary for proper comparisons of the efficacy and safety of gabapentin with placebo.Systematic review registration number: No.

Long-Term Mortality Trends After Total Hip and Knee Arthroplasties: A Population-Based Study

BACKGROUND

Mortality after total hip and knee arthroplasty is lower than that in the general population, but it is unknown whether there are differences by surgery type, demographics, and calendar year. Our objective was to evaluate trends and determinants of long-term mortality among patients with total hip and knee arthroplasties.

METHODS

Using a historical cohort study design, we passively followed up population-based cohorts of total hip and total knee arthroplasty patients with degenerative arthritis who underwent surgery between January 1, 1969 and December 31, 2008. Patients were followed up until death or August 31, 2014. Observed and expected survival was compared using standardized mortality ratios (SMRs). Poisson regression models were used to examine relative mortality patterns by surgery type, age, sex, calendar year, and time since surgery.

RESULTS

The overall age- and sex-adjusted mortality was significantly lower than that in the general population after both total hip (SMR: 0.82, 95% CI: 0.76-0.88) and total knee (SMR = 0.80, 95% CI: 0.75-0.86) arthroplasties. Despite the low relative mortality within the first 8 years of surgery, we observed a worsening of relative mortality beyond 15 years after total knee arthroplasty surgery. Both short- and long-term mortality improved over calendar time, and the improvement occurred about a decade earlier in total knee arthroplasty than in total hip arthroplasty.

CONCLUSION

Survival after total hip and total knee arthroplasties is better than that in the general population for about 8 years after surgery. Secular trends are encouraging and suggest that survival after both procedures has been improving even further in recent years.

Does knee replacement surgery for osteoarthritis improve survival? The jury is still out

BACKGROUND

The relation of knee replacement (KR) surgery to all-cause mortality has not been well established owing to potential biases in previous studies. Thus, we aimed to examine the relation of KR to mortality risk among patients with knee osteoarthritis (OA) focusing on identifying biases that may threaten the validity of prior studies.

METHODS

We included knee OA subjects (ages 50-89 years) from The Health Improvement Network, an electronic medical records database in the UK. Risk of mortality among KR subjects was compared with propensity score-matched non-KR subjects. To explore residual confounding bias, subgroup analyses stratified by age and propensity scores were performed.

RESULTS

Subjects with KR had 28% lower risk of mortality than non-KR subjects (HR 0.72, 95% CI 0.66 to 0.78). However, when stratified by age, protective effect was noted only in older age groups (>63 years) but not in younger subjects (≤63 years). Further, the mortality rate among KR subjects decreased as candidacy (propensity score) for KR increased among subjects with KR, but no such consistent trend was noted among non-KR subjects.

CONCLUSIONS

While a protective effect of KR on mortality cannot be ruled out, findings of lower mortality among older KR subjects and those with higher propensity scores suggest that prognosis-based selection for KR may lead to intractable confounding by indication; hence, the protective effect of KR on all-cause mortality may be overestimated.

Criteria used when deciding on eligibility for total knee arthroplasty--Between thinking and doing

BACKGROUND

Clinical decision-making in total knee arthroplasty (TKA) is a complex process needing further clarification. The aim of this study was to compare TKA eligibility criteria considered most important by orthopedic surgeons (OSs) to characteristics of patients with knee osteoarthritis (OA) eventually found eligible for TKA.

METHODS

Nine OSs chose the five criteria most important when deciding on TKA eligibility. Cross-sectional data from 200 patients found either eligible (n=100) or not eligible (n=100) for TKA by one of the nine OS, were analyzed in a regression analyses with TKA eligibility as the dependent variable.

RESULTS

Radiographic severity (n=8), pain (n=9), functional disability (n=8) and not responding to the recommended non-surgical treatment (n=7) were considered most important by OSs. Associations (P<0.25) between TKA eligibility and criteria found important by the OS were demonstrated for worse radiographic severity and more functional limitations, but not for pain and not responding to the recommended non-surgical treatment. Furthermore, more comorbidities and higher Body Mass Index (BMI) were associated with TKA-eligibility, but not found important for TKA eligibility by the OS.

CONCLUSION

Radiographic severity and functional limitations were confirmed as drivers for TKA eligibility, while pain was not. Not responding to non-surgical treatment was not included in the decision-making, suggesting low uptake of clinical guidelines in clinical practice. This study highlights the complexity of the decision-making with some overlap between the criteria that OSs think they apply and what is actually applied in clinical practice.

A Randomized, Controlled Trial of Total Knee Replacement

BACKGROUND

More than 670,000 total knee replacements are performed annually in the United States; however, high-quality evidence to support the effectiveness of the procedure, as compared with nonsurgical interventions, is lacking.

METHODS

In this randomized, controlled trial, we enrolled 100 patients with moderate-to-severe knee osteoarthritis who were eligible for unilateral total knee replacement. Patients were randomly assigned to undergo total knee replacement followed by 12 weeks of nonsurgical treatment (total-knee-replacement group) or to receive only the 12 weeks of nonsurgical treatment (nonsurgical-treatment group), which was delivered by physiotherapists and dietitians and consisted of exercise, education, dietary advice, use of insoles, and pain medication. The primary outcome was the change from baseline to 12 months in the mean score on four Knee Injury and Osteoarthritis Outcome Score subscales, covering pain, symptoms, activities of daily living, and quality of life (KOOS4); scores range from 0 (worst) to 100 (best).

RESULTS

A total of 95 patients completed the 12-month follow-up assessment. In the nonsurgical-treatment group, 13 patients (26%) underwent total knee replacement before the 12-month follow-up; in the total-knee-replacement group, 1 patient (2%) received only nonsurgical treatment. In the intention-to-treat analysis, the total-knee-replacement group had greater improvement in the KOOS4 score than did the nonsurgical-treatment group (32.5 vs. 16.0; adjusted mean difference, 15.8 [95% confidence interval, 10.0 to 21.5]). The total-knee-replacement group had a higher number of serious adverse events than did the nonsurgical-treatment group (24 vs. 6, P=0.005).

CONCLUSIONS

In patients with knee osteoarthritis who were eligible for unilateral total knee replacement, treatment with total knee replacement followed by nonsurgical treatment resulted in greater pain relief and functional improvement after 12 months than did nonsurgical treatment alone. However, total knee replacement was associated with a higher number of serious adverse events than was nonsurgical treatment, and most patients who were assigned to receive nonsurgical treatment alone did not undergo total knee replacement before the 12-month follow-up. (Funded by the Obel Family Foundation and others; MEDIC ClinicalTrials.gov number, NCT01410409.).

Quantifying the Burden of Revision Total Joint Arthroplasty for Periprosthetic Infection

Periprosthetic joint infection (PJI) represents substantial clinical and economic burdens. This study evaluated patient and procedure characteristics and resource utilization associated with revision arthroplasty for PJI. The Nationwide Inpatient Sample (Q4 2005-2010) was analyzed for 235,857 revision THA (RTHA) and 301,718 revision TKA (RTKA) procedures. PJI was the most common indication for RTKA, and the third most common reason for RTHA. PJI was most commonly associated with major severity of illness (SOI) in RTHA, and with moderate SOI in RTKA. RTHA and RTKA for PJI had the longest length of stay. Costs were higher for RTHA/RTKA for PJI than for any other diagnosis except periprosthetic fracture. Epidemiologic differences exist in the rank, severity and populations for RTHA and RTKA for PJI.

Trends in High Tibial Osteotomy and Knee Arthroplasty Utilizations and Demographics in Korea From 2009 to 2013

We analyzed the records of 29,895 high tibial osteotomies (HTOs), 12,589 unicompartmental knee arthroplasties (UKAs) and 363,386 total knee arthroplasties (TKAs) performed from 2009 to 2013 in Korea. They were compared with the latest nationwide registry reports of seven Western countries. Over the last 5 years, in Korea, the number of HTO, UKA and TKA increased by 210%, 138%, and 18%, respectively. The largest increase was observed in 55-64 year olds in HTO and UKA, while the largest increase in TKA was in ≥75 year olds. Females commonly had a three- to seven-fold higher rate in all procedures. Worldwide, the use of HTO and UKA decreased or remained stable, whereas that of TKA increased steadily, even in younger patients.

Return to Work and Functional Outcomes Following Primary Total Knee Arthroplasty in U.S. Military Servicemembers

This investigation sought to determine occupational outcomes after total knee arthroplasty (TKA) in a high-demand cohort. A total of 159 military servicemembers underwent 181 primary TKAs with mean follow-up of 4.1 (range, 2.0-6.6) years. Approximately 18% of servicemembers underwent medical separation from the military due to TKA-related limitations, and age <45 years (OR=2.36; 95% CI: 1.14, 4.90) was established as the significant risk factor. Twenty servicemembers (12.6%) performed postoperative combat deployments, with age <45 years (OR=3.10; 95% CI: 1.29, 7.47) or combat arms designation (OR=2.75; 95% CI: 1.13, 6.73) associated with higher rates of deployment. Nine revision TKAs (5.0%) were performed at an average of 1.9 years. Following TKA, 82% of servicemembers remained on active-duty or completed their military service.

LEVEL OF EVIDENCE

IV.

Comparative Epidemiology of Revision Arthroplasty: Failed THA Poses Greater Clinical and Economic Burdens Than Failed TKA

BACKGROUND

Revision THA and TKA are growing and important clinical and economic challenges. Healthcare systems tend to combine revision joint replacement procedures into a single service line, and differences between revision THA and revision TKA remain incompletely characterized. These differences carry implications for guiding care and resource allocation. We therefore evaluated epidemiologic trends associated with revision THAs and TKAs.

QUESTIONS/PURPOSES

We sought to determine differences in (1) the number of patients undergoing revision TKA and THA and respective demographic trends; (2) differences in the indications for and types of revision TKA and THA; (3) differences in patient severity of illness scoring between THA and TKA; and (4) differences in resource utilization (including cost and length of stay [LOS]) between revision THA and TKA.

METHODS

The Nationwide Inpatient Sample (NIS) was used to evaluate 235,857 revision THAs and 301,718 revision TKAs between October 1, 2005 and December 31, 2010. Patient characteristics, procedure information, and resource utilization were compared across revision THAs and TKAs. A revision burden (ratio of number of revisions to total number of revision and primary surgeries) was calculated for hip and knee procedures. Severity of illness scoring and cost calculations were derived from the NIS. As our study was principally descriptive, statistical analyses generally were not performed; however, owing to the large sample size available to us through this NIS analysis, even small observed differences presented are likely to be highly statistically significant.

RESULTS

Revision TKAs increased by 39% (revision burden, 9.1%-9.6%) and THAs increased by 23% (revision burden, 15.4%-14.6%). Revision THAs were performed more often in older patients compared with revision TKAs. Periprosthetic joint infection (25%) and mechanical loosening (19%) were the most common reasons for revision TKA compared with dislocation (22%) and mechanical loosening (20%) for revision THA. Full (all-component) revision was more common in revision THAs (43%) than in TKAs (37%). Patients who underwent revision THA generally were sicker (> 50% major severity of illness score) than patients who underwent revision TKA (65% moderate severity of illness score). Mean LOS was longer for revision THAs than for TKAs. Mean hospitalization costs were slightly higher for revision THA (USD 24,697 +/- USD 40,489 [SD]) than revision TKA (USD 23,130 +/- USD 36,643 [SD]). Periprosthetic joint infection and periprosthetic fracture were associated with the greatest LOS and costs for revision THAs and TKAs.

CONCLUSIONS

These data could prove important for healthcare systems to appropriately allocate resources to hip and knee procedures: the revision burden for THA is 52% greater than for TKA, but revision TKAs are increasing at a faster rate. Likewise, the treating clinician should understand that while both revision THAs and TKAs bear significant clinical and economic costs, patients undergoing revision THA tend to be older, sicker, and have greater costs of care.

Periprosthetic fractures around polished collarless cemented stems: the effect of stem design on fracture pattern

BACKGROUND

Predictable patterns of periprosthetic fracture have been observed around polished double tapered stems. Finite element studies have suggested that triple-tapered stems cause less cement strain in torsion compared to double-tapered stems. Hence, we hypothesised that the in vitro behaviour of implanted double- and triple-tapered polished stems, like the CPT (Zimmer, Warsaw, USA) or C-Stem (DePuy, Leeds, U.K.) when subjected to pathological torsional loads may cause different patterns of periprosthetic fractures.

METHODS

Ten double-tapered stems (CPT) and ten triple-tapered stems (C-Stem) were cemented into synthetic femur bones. A constant axial compression load of 100 N and a torsional pre-load of 0.1 N.m were applied using a biaxial testing machine. The distal femur was then loaded in external rotation at 45 degrees until failure.

RESULTS

Seven of the 10 CPT stems fractured at the level of the stem body while fracturing the cement mantle at the same level. In three of ten of the CPT stems and all ten C-Stems, the synthetic bone fractured at the tip of the prosthesis while the cement mantle remained intact. This was significant for the resulting fracture pattern (P=0.001). There was no significant difference between the groups for either torque (P=0.13) or angle at failure (P=0.49).

INTERPRETATION

This biomechanical study indicates that the CPT and C-Stem create a different fracture pattern under the same loading condition. The C-Stem (a triple tapered stem) may produce lower strain in torsion to the cement mantle of a cemented THA. However, fractures that do occur may be more difficult to treat than those produced around a stem like the CPT subjected to comparable loading.

Metal ions as inflammatory initiators of osteolysis

Osteolysis and aseptic loosening currently contribute 75 % of implant failures. Furthermore, with over four million joint replacements projected to be performed in the United States annually, osteolysis and aseptic loosening may continue to pose a significant morbidity. This paper reviews the osteolysis cascade leading to osteoclast activation and bone resorption at the biochemical level. Additionally, the metal ion release mechanism from metallic implants is elucidated. Even though metal ions are not the predominating initiator of osteolysis, they do increase the concentration of key inflammatory cytokines that stimulate osteoclasts and prove to be a contributor to osteolysis and aseptic loosening. Osteolysis is a competitive mechanism among a number of biological reactions, which includes debris release, macrophage and osteoclast activation, an inflammatory response as well as metal ion release. Pharmacological therapy for component loosening has also been reviewed. A non-surgical treatment of osteolysis has not been found in the literature and thus may become an area of future research. Even though this research is warranted, comprehensively understanding the immune response to orthopedic implants and their metallic ions, and thus, creating improved prostheses appears to be the most cost-effective approach to decrease the morbidity related to osteolysis and to design implants with greater longevity. The ionic forms, cytokines, toxicity, gene expression, biological effects, and hypersensitivity responses of metallic elements from metal implants are summarized as well.

Muscle inflammation susceptibility: a prognostic index of recovery potential after hip arthroplasty?

While elective total hip arthroplasty (THA) for end-stage osteoarthritis (OA) improves pain, mobility function, and quality of life in most cases, a large proportion of patients suffer persistent muscle atrophy, pain, and mobility impairment. Extensive skeletal muscle damage is unavoidable in these surgical procedures, and it stands to reason that poor recovery and long-term mobility impairment among some individuals after THA is linked to failed muscle regeneration and regrowth following surgery and that local muscle inflammation susceptibility (MuIS) is a major contributing factor. Here we present results of two integrated studies. In study 1, we compared muscle inflammation and protein metabolism signaling in elective THA (n=15) vs. hip fracture/trauma (HFX; n=11) vs. nonsurgical controls (CON; n=19). In study 2, we compared two subgroups of THA patients dichotomized into MuIS⁺ (n=7) or MuIS⁻ (n=7) based on muscle expression of TNF-like weak inducer of apoptosis (TWEAK) receptor (Fn14). As expected, HFX demonstrated overt systemic and local muscle inflammation and hypermetabolism. By contrast, no systemic inflammation was detected in elective THA patients; however, local muscle inflammation in the perioperative limb was profound in MuIS⁺ and was accompanied by suppressed muscle protein synthesis compared with MuIS⁻. Muscle from the contralateral limb of MuIS⁺ was unaffected, providing evidence of a true inflammation susceptibility localized to the muscle surrounding the hip with end-stage OA. We suggest MuIS status assessed at the time of surgery may be a useful prognostic index for muscle recovery potential and could therefore provide the basis for a personalized approach to postsurgery rehabilitation.

Racial disparities in total ankle arthroplasty utilization and outcomes

INTRODUCTION

The objective of this study was to examine the racial disparities in total ankle arthroplasty (TAA) utilization and outcomes.

METHODS

We used the National Inpatient Sample (NIS) to study the time-trends. Race was categorized as White and Black. Utilization rates were calculated for the U.S. general population per 100,000. Hospital length of stay, discharge disposition and mortality after TAA were assessed. We used the Cochran Armitage trend test to assess time-trends from 1998 to 2011 and chi-square test to compare TAA utilization. We used analysis of variance or chi-squared test to compare the characteristics of Whites and Blacks undergoing TAA and logistic regression to compare mortality, length of stay and discharge to home versus medical facility.

RESULTS

The mean ages for Whites undergoing TAA were 62 years and for Blacks was 52 years. Significant racial disparities were noted in TAA utilization rates (/100,000) in 1998, 0.14 in Whites vs. 0.07 in Blacks (P<0.0001; 2-fold) and in 2011, 1.17 in Whites vs. 0.33 in Blacks (P<0.0001; 4-fold). Racial disparities in TAA utilization increased significantly from 1998 to 2011 (P<0.0001). There was a trend towards statistical significance for the difference in the length of hospital stay in Blacks vs. Whites (52.9% vs. 44.3% with length of hospital stay higher than the median; P=0.08). Differences in the proportion discharged to an inpatient medical facility after TAA, 16.6% Blacks vs. 13.4% Whites, were not significant (P=0.36).

CONCLUSIONS

This study demonstrated significant racial disparities with lower TAA utilization and suboptimal outcomes in Blacks compared to Whites. Further studies are needed to understand the mediators of these disparities and to assess whether these mediators can be targeted to reduce racial disparities in TAA.

Clinical and economic characteristics of total hip replacement patients with high health care costs and high health care use

OBJECTIVE

The aims of this study were to confirm whether total hip arthroplasty (THA) patients with muscle atrophy/weakness (MAW) have high health care costs and resource use and to identify the characteristics that contribute to these high costs and use.

DESIGN

This study analyzed claims from United States patients who underwent THA identified from commercial (n = 25,249) and Medicare (n = 22,472) insurance databases to compare demographics, health care costs, and resource use among patients with or without MAW. The patients were classified into three separate cohorts: pre-MAW (having MAW during the 12 mos before THA), post-MAW (having MAW during the 12 mos after THA, and no-MAW (no MAW claim). Characteristics of the THA patients associated with high health care costs were examined by multiple logistic regression, and subgroups of patients with high cost and high resource use were identified by classification and regression tree analyses.

RESULTS

Health care use and costs were significantly higher for the THA patients with MAW, who had greater likelihood of inpatient and emergency department use and stays at skilled nursing facilities than the no-MAW patients. Classification and regression tree identified subgroups of high-cost patients as those with MAW having extended hospital stays and more outpatient visits.

CONCLUSIONS

THA patients with MAW are at greater risk for high health care costs and resource consumption, including longer hospital stays, increased outpatient visits, and stays at skilled nursing and inpatient rehabilitation facilities.

Total knee arthroplasty: Effect of obesity and other patients’ characteristics on operative duration and outcome

AIM: To examine the effects of patients’ characteristics mainly obesity on operative duration and other outcome measures of knee arthroplasty.

METHODS: This is a retrospective chart review of 204 patients who had knee arthroplasty within the past five years (2007-2011) at King Abdulaziz Medical City in Riyadh, Kingdom of Saudi Arabia. The data collection form was developed utilizing the literature review to gather all the needed variables. Data were gathered from admission notes, nursing notes, operative reports and discharge summaries.

RESULTS: A feasible sample of 204 patients were included in the study. Of those patients, 155 (76%) were females. The mean age was 70.1 years for males (SD ± 9.4) and 62.7 years (SD ± 8) for females. Regarding the type of total knee replacement (TKR), 163 (79.9%) patients had unilateral TKR and 41 (20.1%) had bilateral TKR. Nine patients (4.4%) had a normal body mass index (BMI) (18.5 to < 25). Overweight patients (BMI 25 to < 30) represented 18.1%. Obesity class I (BMI 30 to < 35) and obesity class II (BMI from 35 to < 40) were present in 23% and 29.9% of the patients, respectively. Morbid obesity (BMI greater than 40) was present in 24.5%. The mean duration of surgery was 126.3 min (SD ± 30.8) for unilateral TKR and 216.6 min (SD ± 55.4) for bilateral TKR.The mean length of stay in the hospital was 12 d (SD ± 4.9). The complications that patients had after the operation included 2 patients (1%) who developed deep venous thrombosis, 2 patients (1%) developed surgical wound infections and none had pulmonary embolism. Patients' characteristics (including age, gender, BMI and co-morbidities) did not have an effect on the operative duration of knee replacement nor the length of hospital stay.

CONCLUSION: Our study shows that obesity and other patients’ characteristics do not have effect on the operative duration nor the length of hospital stay following TKR.

Clinical trial to evaluate the performance of a flexible self-adherent absorbent dressing coated with a soft silicone layer compared to a standard wound dressing after orthopedic or spinal surgery: study protocol for a randomized controlled trial

BACKGROUND

Postoperative wound infection is a preventable risk. One potential postoperative complication is blistering, which leads to increased pain, delayed healing, and higher care costs. The incidence of wound blisters has been reported to be between 6 and 24%. The aim of this study is to assess whether the risks of postoperative blistering and wound infections within the first 6 days postsurgery will be reduced using a special dressing compared to a standard one.

METHODS/DESIGN

This is a randomized clinical trial in a University hospital. Patients presenting for knee or hip arthroplasty or spine procedures will be assessed against study inclusion and exclusion criteria. After giving written informed consent, patients will be randomized to participate in the 7-day study during hospitalization. One hundred patients will be randomized per group. The primary outcome measure is blistering incidence from day 0 to day 6 postsurgery. Photo documentation will be evaluated in a blinded manner by the Clinical Evaluation Committee (CEC).

DISCUSSION

A new dressing will be compared to the standard wound dressing regarding the risk of postoperative blistering, wound infection, and patient comfort. This study will assess the potential advantages of a modern wound dressing.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01988818 (Entered 13 November 2011).