Optimizing anterior cruciate ligament reconstruction: Individualizing the decision-making process using data from the Kaiser Permanente ACLR Registry: 2018 OREF award paper

Despite years of study, controversy remains regarding the optimal graft for anterior cruciate ligament reconstruction (ACLR), suggesting that a single graft type is not ideal for all patients. A large community based ACLR Registry that collects prospective data is a powerful tool that captures information and can be analyzed to optimize surgery for individual patients. The studies highlighted in this paper were designed to optimize and individualize ACLR surgery and have led to changes in surgeon behavior and improvements in patient outcomes. Kaiser Permanente (KP) is an integrated health care system with 10.6 million members and more than 50 hospitals. Every KP member who undergoes an ACLR is entered into the Registry, and prospectively monitored. The Registry uses a variety of feedback mechanisms to disseminate Registry findings to the ACLRR surgeons and appropriately influence clinical practices and enhance quality of care. Allografts were found to have a 3.0 times higher risk of revision than bone-patellar tendon-bone (BPTB) autografts. Allograft irradiation >1.8 Mrad, chemical graft processing, younger patients, BPTB allograft, and male patients were all associated with a higher risk of revision surgery. By providing feedback to surgeons, overall allograft use has decreased by 27% and allograft use in high-risk patients ≤21 years of age decreased 68%. We have identified factors that influence the outcomes of ACLR. Statement of Clinical Significance: We found that information derived from an ACLR Registry and shared with the participating surgeons directly decreased the use of specific procedures and implants associated with poor outcomes.

Cardiac Implantable Electronic Devices: Reoperations and the Competing Risk of Death

BACKGROUND

The use of cardiac implantable electronic devices (CIED), which includes pacemakers, implantable cardioverter-defibrillators (ICD), cardiac resynchronisation therapy pacemakers (CRT-P) and cardiac resynchronisation therapy defibrillators (CRT-D) has increased over the past 20 years, but there is a lack of real world evidence on the longevity of these devices in the older population which is essential to inform health care delivery and support clinical decisions.

METHODS AND RESULTS

We conducted a retrospective cohort study using data from the Australian Government Department of Veterans' Affairs database. The cohort consisted of people who had a CIED procedure between 2005 and 2015. The cumulative risk of generator replacement/reoperations was estimated accounting for the competing risk of death. A total of 16,662 patients were included. In pacemaker recipients with an average age of 85 years, the 5-year risk of reoperation ranged from 2.8% in single chamber, 3.6% in dual chamber to 7.6% in CRT-P recipients, while the 5-year risk of dying with the index pacemaker in situ was 63% in single chamber, 46% in dual chamber and 56% in CRT-P recipients. In defibrillator recipients with an average age of 80 years, the 5-year risk of reoperation ranged from 11% in single chamber, 13% in dual chamber to 24% in CRT-D recipients, while the 5-year risk of dying with the index defibrillator in situ was 46% in single chamber, 40% in dual chamber and 41% in CRT-D recipients.

CONCLUSION

In this cohort of older patients the 5-year risk of generator reoperation was low in pacemaker recipients whereas up to one in four CRT-D recipients would have a reoperation within 5 years.

Lumbar Spine Fusion Patients See Similar Improvements in Physical Activity Level to Non-Spine Fusion Patients Following Total Hip Arthroplasty

BACKGROUND

The impact of prior lumbar spinal fusion on the change in physical activity level following total hip arthroplasty (THA) has not been thoroughly examined. Therefore, we sought to compare the change in physical activity level following THA for patients with and without a history of lumbar spine fusion.

METHODS

Patients who underwent primary elective THA were identified using an integrated healthcare system's Total Joint Replacement Registry (2010-2013). Prior lumbar spine fusion was identified using the healthcare system's Spine Registry. Physical activity was self-reported by patients and measured in min/wk. Generalized linear models were used to evaluate the association between prior spine fusion and the change in physical activity from 1 year pre-THA to 1-2 years post-THA.

RESULTS

Of 11,416 THAs, 90 (0.8%) had a history of lumbar spinal fusion. Patients with a prior lumbar fusion had a median physical activity level of 28 min/wk prior to THA compared to 45 min/wk in the patients with no history of lumbar spinal fusion. One year after THA, patients with a history of lumbar spinal fusion reported a median of 120 min/wk of physical activity compared to 150 min/wk for patients without a history of lumbar spinal fusion. The difference in physical activity level change between groups was not statistically significant (estimate = -23.1, 95% confidence interval -62.1 to 15.9, P = .246).

CONCLUSION

Patients with prior lumbar fusion were found to have lower self-reported physical activity levels than patients without spine fusion both before and after THA surgery. However, both groups saw the same degree of improvement in physical activity level following THA. These findings may help in counseling patients who have had a prior lumbar spine fusion and in setting appropriate expectations prior to THA.

Preoperative Risk Factors for Opioid Utilization After Total Hip Arthroplasty

BACKGROUND

Opioid prescriptions following orthopaedic procedures may contribute to the opioid epidemic in the United States. Risk factors for greater and prolonged opioid utilization following total hip arthroplasty have yet to be fully elucidated. We sought to determine the prevalence of preoperative and postoperative opioid utilization in a cohort of patients who underwent total hip arthroplasty and to identify preoperative risk factors for prolonged utilization of opioids following total hip arthroplasty.

METHODS

A cohort study of patients who underwent primary elective total hip arthroplasty at Kaiser Permanente from January 2008 to December 2011 was conducted. The number of opioid prescriptions dispensed per 90-day period after total hip arthroplasty (up to 1 year) was the outcome of interest. The risk factors evaluated included preoperative analgesic medication use, patient demographic characteristics, comorbidities, and other history of chronic pain. Poisson regression models were used, and relative risks (RRs) and 95% confidence intervals (CIs) are presented.

RESULTS

Of the 12,560 patients who underwent total hip arthroplasty and were identified, 58.5% were female and 78.6% were white. The median age was 67 years (interquartile range, 59 to 75 years). Sixty-three percent of patients filled at least 1 opioid prescription in the 1 year prior to the total hip arthroplasty. Postoperative opioid use went from 88.6% in days 1 to 90 to 24% in the last quarter. An increasing number of preoperative opioid prescriptions was associated with a greater number of prescriptions over the entire postoperative period, with an RR of 1.10 (95% CI, 1.10 to 1.11) at days 271 to 360. Additional factors associated with greater utilization over the entire year included black race, chronic pulmonary disease, anxiety, substance abuse, and back pain. Factors associated with greater utilization in days 91 to 360 (beyond the early recovery phase) included female sex, higher body mass index, acquired immunodeficiency syndrome, peripheral vascular disease, and history of non-specific chronic pain.

CONCLUSIONS

We identified preoperative factors associated with greater and prolonged opioid utilization long after the early recovery period following total hip arthroplasty. Patients with these risk factors may benefit from targeted multidisciplinary interventions to mitigate the risk of prolonged opioid use.

CLINICAL RELEVANCE

Opioid prescriptions following orthopaedic procedures are one of the leading causes of chronic opioid use; strategies to reduce the risk of misuse and abuse are needed. At 1 year postoperatively, almost one-quarter of patients who underwent total hip arthroplasty used opioids in the last 90 days of the first postoperative year, which makes understanding risk factors associated with postoperative opioid utilization imperative.

The Association Between Race/Ethnicity and Revision Following ACL Reconstruction in a Universally Insured Cohort

BACKGROUND

There have been few large studies involving multiethnic cohorts of patients treated with anterior cruciate ligament reconstruction (ACLR), and therefore, little is known about the role that race/ethnicity may play in the differential risk of undergoing revision surgery following primary ACLR. The purpose of this study was to evaluate whether differences exist by race/ethnicity in the risk of undergoing the elective procedure of aseptic revision in a universally insured cohort of patients who had undergone ACLR.

METHODS

This was a retrospective cohort study conducted using our integrated health-care system's ACLR registry and including primary ACLRs from 2008 to 2015. Race/ethnicity was categorized into the following 4 groups: non-Hispanic white, black, Hispanic, and Asian. Multivariable Cox proportional-hazard models were used to evaluate the association between race/ethnicity and revision risk while adjusting for age, sex, highest educational attainment, annual household income, graft type, and geographic region in which the ACLR was performed.

RESULTS

Of the 27,258 included patients,13,567 (49.8%) were white, 7,713 (28.3%) were Hispanic, 3,725 (13.7%) were Asian, and 2,253 (8.3%) were black. Asian patients (hazard ratio [HR] = 0.72; 95% confidence interval [CI] = 0.57 to 0.90) and Hispanic patients (HR = 0.83; 95% CI = 0.70 to 0.98) had a lower risk of undergoing revision surgery than did white patients. Within the first 3.5 years postoperatively, we did not observe a difference in revision risk when black patients were compared with white patients (HR = 0.86; 95% CI = 0.64 to 1.14); after 3.5 years postoperatively, black patients had a lower risk of undergoing revision (HR = 0.23; 95% CI = 0.08 to 0.63).

CONCLUSIONS

In a large, universally insured ACLR cohort with equal access to care, we observed Asian, Hispanic, and black patients to have a similar or lower risk of undergoing elective revision compared with white patients. These findings emphasize the need for additional investigation into barriers to equal access to care. Because of the sensitivity and complexity of race/ethnicity with surgical outcomes, continued assessment into the reasons for the differences observed, as well as any differences in other clinical outcomes, is warranted.

LEVEL OF EVIDENCE

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

Rehospitalizations for complications and mortality following pacemaker implantation: A retrospective cohort study in an older population

INTRODUCTION

A large number of older people receive pacemakers each year but broad population-based studies that describe complications following pacemaker implantation in this population are lacking.

METHODS

We conducted a retrospective cohort study using data from the Australian Government Department of Veterans' Affairs database. The cohort consisted of patients who received a pacemaker from 2005 to 2014. The outcomes were subsequent rehospitalizations for infections, procedure-related complications, thromboembolism, cardiovascular events (heart failure, myocardial infarction, and atrial fibrillation), and reoperation of pacemaker, and mortality.

RESULTS

There were 10 883 pacemakers recipients, the median age was 86 years (interquartile range 83-89), 61% were males, and 74% received a dual-chamber pacemaker. Within 90 days postdischarge, rehospitalizations were occasioned by pacemaker infection in 0.5%, device-related complications in 1.5%, cerebral infarction in 0.7%, and heart failure in 6% of single-chamber pacemaker recipients. In dual-chamber pacemaker recipients rehospitalizations were occasioned by pacemaker infection in 0.4%, septicemia in 0.4%, device-related complications in 1.2%, cerebral infarction in 0.3%, and heart failure in 3%. Rehospitalizations for pacemaker adjustment occurred in 1.5% of patients. The 90-day postdischarge mortality was 5% and 3% in patients with single- and dual-chamber pacemaker, respectively.

CONCLUSION

Rehospitalizations for infection, procedure-related complications, or thromboembolism occurred in 1% to 2% of patients within 90 days postdischarge, while 10% of single chamber and 7% of dual-chamber recipients experienced a rehospitalization for a cardiovascular event.

Patient Factors Associated With Prolonged Postoperative Opioid Use After Total Knee Arthroplasty

BACKGROUND

Pain persists in a moderate proportion of patients after total knee arthroplasty (TKA). Identifying patient factors that are associated with persistent pain may lead to improved care.

PURPOSE

The purpose of the study was to identify preoperative factors associated with increased opioid prescriptions after TKA.

METHODS

A retrospective cohort study of TKAs in an integrated health-care system (January 2008-December 2011) was conducted. The number of opioid prescriptions per 90-day period after TKA (up to 1 year), was the outcome of interest. Patient risk factors that were evaluated included demographics, pain prescriptions, comorbidities, and chronic pain conditions. Multivariable Poisson regression models were employed.

RESULTS

The median age for 23,726 patients was 67 years. Before surgery, 60.0% used opioids. Three months after surgery, 41.2% of patients continued using opioids. Factors associated with greater opioid use included: younger age (odds ratio [OR] = 0.83, 95% confidence interval [CI] 0.82-0.84 per 10-year increase), liver disease (OR = 1.11, 95% CI 1.06-1.16), preoperative nonsteroidal anti-inflammatory drug use (OR = 1.09, 95% CI 1.07-1.10), anxiety (OR = 1.05, 95% CI 1.03-1.08), substance abuse (OR = 1.03, 95% CI 1.00-1.06), diabetes mellitus (OR = 1.03, 95% CI 1.01-1.05), preoperative opioid use (OR = 1.04, 95% CI 1.04-1.04), back pain (OR = 1.23, 95% CI 1.18-1.127), congestive heart failure (OR = 1.16, 95% CI 1.06-1.27), depression (OR = 1.14, 95% CI 1.09-1.18), fibromyalgia (OR = 1.10, 95% CI 1.02-1.18), hypertension (OR = 1.06, 95% CI 1.02-1.10), nonspecific chronic pain (OR = 1.06, 95% CI 1.02-1.10), black race (OR = 1.17, 95% CI 1.12-1.23), and chronic lung disease (OR = 1.05, 95% CI 1.01-1.10).

CONCLUSION

Several preoperative factors were associated with prolonged opioid use after TKA, and their identification can assist providers guide pain management. Avoidance or weaning of preoperative opioids should be considered.

Mortality After Total Knee and Total Hip Arthroplasty in a Large Integrated Health Care System

CONTEXT

The number of excess deaths associated with elective total joint arthroplasty in the US is not well understood.

OBJECTIVE

To evaluate one-year postoperative mortality among patients with elective primary and revision arthroplasty procedures of the hip and knee.

DESIGN

A retrospective analysis was conducted of hip and knee arthroplasties performed in 2010. Procedure type, procedure volume, patient age and sex, and mortality were obtained from an institutional total joint replacement registry. An integrated health care system population was the sampling frame for the study subjects and was the reference group for the study.

MAIN OUTCOME MEASURES

Standardized 1-year mortality ratios (SMRs) and 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 10,163 primary total knee arthroplasties (TKAs), 4963 primary total hip arthroplasties (THAs), 606 revision TKAs, and 496 revision THAs were evaluated. Patients undergoing primary THA (SMR = 0.6, 95% CI = 0.4-0.7) and TKA (SMR = 0.4, 95% CI = 0.3-0.5) had lower odds of mortality than expected. Patients with revision TKA had higher-than-expected mortality odds (SMR = 1.8, 95% CI = 1.1-2.5), whereas patients with revision THA (SMR = 0.9, 95% CI = 0.4-1.5) did not have higher-than-expected odds of mortality.

CONCLUSION

Understanding excess mortality after joint surgery allows clinicians to evaluate current practices and to determine whether certain groups are at higher-than-expected mortality risk after surgery.

Prevalence and changes in analgesic medication utilisation 1 year prior to total joint replacement in an older cohort of patients

OBJECTIVES

To evaluate the prevalence and change in analgesic medications use prior to joint replacement in older patients between 2001 and 2012.

METHODS

A population based epidemiological study was conducted. Opioids, non-steroidal anti-inflammatories (NSAIDs), paracetamol, corticosteroid injections, medications for neuropathic pain, hypnotics, and muscle relaxants supplied 1 year prior to total knee replacement (TKR, n = 15,517) and hip replacement (THR, n = 10,018) were assessed. Patient characteristics and surgical indication adjusted prevalence ratios (PRs) and 95% confidence intervals (CI) are provided.

RESULTS

From 2001 to 2012, in the TKR cohort (median age 78.9) the prevalence of opioid use prior to surgery increased from 37% to 49% (PR = 1.01, 95% CI 1.00-1.01, P = 0.01), while in the THR cohort (median age 81.1) it increased from 44% to 54% (PR = 1.01, 95% CI 1.01-1.02, P < 0.001). Paracetamol use increased from 52% to 61% (PR = 1.0, 95% CI 1.0-1.0, P = 0.913) in the TKR cohort and from 55% to 67% (PR = 1.01, 95% CI 1.00-1.01, P = 0.005) in the THR cohort. Neuropathic pain medication use increased from 5% to 11% in the TKR cohort (PR = 1.04, 95% CI 1.02-1.06, P < 0.0001) and from 6% to 12% in the THR cohort (PR = 1.06, 95% CI 1.04-1.09, P < 0.0001). NSAID use decreased from 76% to 50% in the TKR cohort (PR = 0.96, 95% CI 0.95-0.96, P < 0.0001), and from 81% to 47% in THR cohort (PR = 0.95, 95% CI 0.94-0.95, P < 0.0001). Corticosteroid injections prevalence also decreased (TKR: 21-18%, PR = 0.97, 95% CI 0.96-0.97, P < 0.001, THR: 18-17%, PR = 0.97, 95% CI 0.96-0.98, P < 0.001).

CONCLUSION

Pain medication utilization prior to joint replacement surgery changed significantly in this national older cohort of patients during the 2000s.

Persistent Opioid Use Following Total Knee Arthroplasty: A Signal for Close Surveillance

BACKGROUND

Prolonged opioid use following total knee arthroplasty (TKA) has not been extensively studied.

METHODS

A cohort study of primary TKA for osteoarthritis using an integrated healthcare system and Total Joint Replacement Registry (January 2008-December 2011) was conducted. Opioid use during the first year after TKA was the exposure of interest and cumulative daily oral morphine equivalent (OME) amounts were calculated. Total postsurgical OME per 90-day exposure periods were categorized into quartiles. The end point was aseptic revision surgery. Survival analyses were conducted and hazard ratios (HRs) were adjusted for age, gender, prior analgesic use, opioid-related comorbidities, and chronic pain diagnoses.

RESULTS

A total of 24,105 patients were studied. After the initial 90-day postoperative period, 41.5% (N = 9914) continued to use opioids. Also, 155 (0.6%) revisions occurred within 1 year and 377 (1.6%) within 5 years. Compared to patients not taking any opioids, patients using medium-low to high OME after the initial 90-day period had a higher adjusted risk of 1-year revision, ranging from HR = 2.4 (95% confidence interval, 1.3-4.5) to HR = 33 (95% confidence interval, 10-110) depending on the OME and time period.

CONCLUSION

Patients who require opioids beyond 90 days after TKA warrant close follow-up.

The Incidence of Subsequent Meniscal Surgery Is Higher in the Anterior Cruciate Ligament-Reconstructed Knee Than in the Contralateral Knee

BACKGROUND

A goal of anterior cruciate ligament (ACL) reconstruction is to provide a meniscal protective effect for the knee.

PURPOSE

(1) To evaluate whether there was a different likelihood of subsequent meniscal surgery in the ACL-reconstructed knee or in the normal contralateral knee and (2) to compare the risk factors associated with subsequent meniscal surgery in the ACL-reconstructed knee and contralateral knee.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Using an integrated health care system's ACL reconstruction registry, patients undergoing primary ACL reconstruction, with no meniscal injury at the time of index surgery and a normal contralateral knee, were evaluated. Subsequent meniscal tears associated with ACL graft revision were excluded. Subsequent meniscal surgery in either knee was the outcome of interest. Sex, age, and graft type were assessed as potential risk factors. Survival analysis was used to compare meniscal surgery-free survival rates and to assess risk factors of subsequent meniscal surgery.

RESULTS

Of 4087 patients, there were 32 (0.78%) patients who underwent subsequent meniscal surgery in the index knee and 9 (0.22%) in the contralateral knee. The meniscal surgery-free survival rate at 4 years was 99.08% (95% CI, 98.64%-99.37%) in the index knee and 99.65% (95% CI, 99.31%-99.82%) in the contralateral knee. There was a 3.73 (95% CI, 1.73-8.04; P < .001) higher risk of subsequent meniscal surgery in the index knee compared with the contralateral knee, or a 0.57% absolute risk difference. After adjustments, allografts (hazard ratio [HR], 5.06; 95% CI, 1.80-14.23; P = .002) and hamstring autografts (HR, 3.11; 95% CI, 1.06-9.10; P = .038) were risk factors for subsequent meniscal surgery in the index knee compared with bone-patellar tendon-bone (BPTB) autografts.

CONCLUSION

After ACL reconstruction, the overall risk of subsequent meniscal surgery was low. However, the relative risk of subsequent meniscal surgery in the ACL-reconstructed knee was higher compared with the contralateral knee. Only graft type was found to be a risk factor for subsequent meniscal surgery in the ACL-reconstructed knee, with a higher risk for allografts and hamstring autografts compared with BPTB autografts.

Projected increase in total knee arthroplasty in the United States - an alternative projection model

OBJECTIVE

The purpose of our study was to estimate the future incidence rate (IR) and volume of primary total knee arthroplasty (TKA) in the United States from 2015 to 2050 using a conservative projection model that assumes a maximum IR of procedures. Furthermore, our study compared these projections to a model assuming exponential growth, as done in previous studies, for illustrative purposes.

METHODS

A population based epidemiological study was conducted using data from US National Inpatient Sample (NIS) and Census Bureau. Primary TKA procedures performed between 1993 and 2012 were identified. The IR, 95% confidence intervals (CI), or prediction intervals (PI) of TKA per 100,000 US citizens over the age of 40 years were calculated. The estimated IR was used as the outcome of a regression modelling with a logistic regression (i.e., conservative model) and Poisson regression equation (i.e., exponential growth model).

RESULTS

Logistic regression modelling suggests the IR of TKA is expected to increase 69% by 2050 compared to 2012, from 429 (95%CI 374-453) procedures/100,000 in 2012 to 725 (95%PI 121-1041) in 2050. This translates into a 143% projected increase in TKA volume. Using the Poisson model, the IR in 2050 was projected to increase 565%, to 2854 (95%CI 2278-4004) procedures/100,000 IR, which is an 855% projected increase in volume compared to 2012.

CONCLUSIONS

Even after using a conservative projection approach, the number of TKAs in the US, which already has the highest IR of knee arthroplasty in the world, is expected to increase 143% by 2050.

Magnetic Resonance Imaging in People With Cardiac Implantable Electronic Devices: A Population Based Cohort Study

Magnetic resonance imaging (MRI) is a widely used diagnostic tool with great benefits but has been considered contraindicated in people with cardiac implantable electronic devices (CIED). We investigated the occurrence of MRI in people with CIEDs and associated adverse events in a national cohort. Of 17,848 people included, 56 (0.3%) had at least one MRI; 16 of 16,102 (0.1%) with MRI non-compatible CIEDs and 40 of 1746 (2%) with MRI compatible CIEDs. Following MRI exposure, hospitalisations for potential serious adverse events were rare.

Isolated ACL versus multiple knee ligament injury: associations with patient characteristics, cartilage status, and meniscal tears identified during ACL reconstruction

OBJECTIVES

The objectives of this study were to determine (1) if patients undergoing reconstruction of an isolated anterior cruciate ligament (ACL) tear had different characteristics (age, gender, body mass index [BMI]) than patients undergoing ACL reconstruction (ACLR) with multiple knee ligament (MKL) tears and (2) whether there was a difference in prevalence of articular cartilage injury and meniscus tears between these two groups.

METHODS

Patients undergoing primary ACLR between February 2005 and June 2013 were identified through an ACLR registry. Patients were grouped by whether they had an isolated ACL tear or an ACL tear associated with another knee ligament tear. The study cohort was analyzed to identify differences in patient characteristics and cartilage/meniscus injury patterns between the groups.

RESULTS

Of the 21,377 ACLR cases enrolled in the registry during the study period, 2.5% (n = 549) had MKL tears. The MKL group had more males (73.2% vs. 62.8%, p < 0.001) than the isolated ACL group. The MKL group also had a higher percentage of patients with a BMI greater than 30 (31.1% vs. 22.7%, p = 0.0002). When adjusting for these variables, any articular cartilage injury was equal in the two groups (OR = 1.01, CI 0.82-1.25, p = 0.922), while medial femoral condyle injury was less common in the MKL group (OR = 0.73, CI = 0.56-0.07, p = 0.28). The likelihood of any meniscus tear was lower in the MKL group (OR = 0.56, CI = 0.47-0.67, p < 0.001) as was the likelihood of medial meniscus tears (OR = 0.53, CI = 0.44-0.65, p < 0.001).

CONCLUSIONS

When comparing patients with MKL tears versus isolated ACL tears at ACLR, there was a higher percentage of males and patients with BMI over 30 in the MKL group. Medial femoral condyle articular cartilage injury, any meniscus tear, and medial meniscus tears were less common in patients with MKL injury compared to patients with isolated ACL tears.

Increase in Total Joint Arthroplasty Projected from 2014 to 2046 in Australia: A Conservative Local Model With International Implications

BACKGROUND

The incidence of joint arthroplasty is increasing worldwide. International estimates of future demand for joint arthroplasty have used models that propose either an exponential future increase, despite obvious system constraints, or static increases, which do not account for past trends. Country-specific projection estimates that address limitations of past projections are necessary. In Australia, a high-income country with the 7th highest incidence of TKA and 15th highest incidence of THA of the Organization for Economic Cooperation and Development (OECD) countries, the volume of TKAs and THAs increased 198% between 1994 and 2014.

QUESTIONS/PURPOSE

To determine the projected incidence and volume of primary TKAs and THAs from 2014 to 2046 in the Australian population older than 40 years.

METHODS

Australian State and Territory Health Department data were used to identify TKAs and THAs performed between 1994 and 1995 and 2013 and 2014. The Australian Bureau of Statistics was the source of the population estimates for the same periods and population-projected estimates until 2046. The incidence rate (IR), 95% CI, and prediction interval (PI) of TKAs and THAs per 100,000 Australian citizens older than 40 years were calculated. Future IRs were estimated using a logistic model, and volume was calculated from projected IR and population. The logistic growth model assumes the existence of an upper limit of the TKA and THA incidences and a growth rate directly related to this incidence. At the beginning, when the observed incidence is much lower than the asymptote, the increase is exponential, but it decreases as it approaches the upper limit.

RESULTS

A 66% increase in the IR of primary THAs between 2013 and 2046 is projected for Australia (2013: IR = 307 per 100,000, [95% CI, 262-329 per 100,000] compared with 2046: IR= 510 per 100,000, [95% PI, 98-567 per 100,000]), which translates to a 219% increase in the volume during this period. For TKAs the IR is expected to increase by 26% by 2046 (IR = 575 per 100,000; 95% PI, 402-717 per 100,000) compared with 2013 (IR = 437 per 100,000; 95% CI, 397-479 per 100,000) and the volume to increase by 142%.

CONCLUSION

A large increase in the volume of arthroplasties is expected using a conservative projection model that accounts for past surgical trends and future population changes in Australia. These findings have international implications, as they show that using country- specific, conservative projection approaches, a substantial increase in the number of these procedures is expected. This increase in joint arthroplasty volume will require appropriate workforce planning, resource allocation, and budget planning so that demand can be met.

LEVEL OF EVIDENCE

Level II, economic and decision analysis.

Increased Risk of Revision After Anterior Cruciate Ligament Reconstruction With Soft Tissue Allografts Compared With Autografts: Graft Processing and Time Make a Difference

BACKGROUND

The optimal graft for anterior cruciate ligament reconstruction (ACLR) remains controversial.

PURPOSE

To compare the risk of aseptic revision between bone-patellar tendon-bone (BPTB) autografts, hamstring autografts, and soft tissue allografts.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Prospectively collected ACLR cases reconstructed with BPTB autografts, hamstring autografts, and soft tissue allografts were identified using the Kaiser Permanente ACLR Registry. Aseptic revision was the endpoint. The type of graft and allograft processing method (nonprocessed, <1.8-Mrad irradiation with and without chemical processing [Allowash or AlloTrue], ≥1.8-Mrad irradiation with and without chemical processing, and chemical processing alone [BioCleanse]) were the exposures evaluated. Analyses were adjusted for age, sex, and race. Kaplan-Meier curves and Cox proportional hazards models were employed.

RESULTS

The cohort included 14,015 cases: there were 8924 (63.7%) male patients, there were 6397 (45.6%) white patients, 4557 (32.5%) ACLRs used BPTB autografts, 3751 ACLRs (26.8%) used soft tissue allografts, and 5707 (40.7%) ACLRs used hamstring autografts. The median age was 34.6 years for soft tissue allografts, 24.3 years for hamstring autografts, and 22.0 years for BPTB autografts. The crude nonadjusted revision rates were 85 (1.9%) in BPTB autograft cases, 132 (2.3%) in hamstring autograft cases, and 83 (2.2%) in soft tissue allograft cases. After adjusting for age, sex, and race, compared with hamstring autografts, a higher risk of revision was found with allografts with ≥1.8 Mrad without chemical processing after 2.5 years (hazard ratio [HR], 3.88; 95% CI, 1.48-10.12) and ≥1.8 Mrad with chemical processing after 1 year (HR, 3.43; 95% CI, 1.58-7.47) and with BioCleanse processed grafts at any time point (HR, 3.02; 95% CI, 1.40-6.50). Nonprocessed allografts and those irradiated with <1.8 Mrad with or without chemical processing were not found to have a different risk of revision compared with hamstring autografts. Compared with BPTB autografts, a higher risk of revision was seen with hamstring autografts (HR, 1.51; 95% CI, 1.15-1.99) and BioCleanse processed allografts (HR, 4.67; 95% CI, 2.15-10.16). Allografts irradiated with <1.8 Mrad with chemical processing (Allowash or AlloTrue) (HR, 2.19; 95% CI, 1.42-3.38) and without chemical processing (HR, 2.31; 95% CI, 1.40-3.82) had a higher risk of revision, as did allografts with ≥1.8 Mrad without chemical processing after 2 years (HR, 6.30; 95% CI, 3.18-12.48) and ≥1.8 Mrad with chemical processing (Allowash or AlloTrue) after 1 year (HR, 5.03; 95% CI, 2.30-11.00) compared with BPTB autografts. Nonprocessed allografts did not have a higher risk of revision compared with autografts. With the numbers available, direct comparisons between the specific allograft processing methods were not possible.

CONCLUSION

When soft tissue allografts are used for ACLR, processing and time from surgery affect the risk of revision. Tissue processing has a significant effect on the risk of revision surgery, which is most profound with more highly processed grafts and increases with increasing follow-up time. Surgeons and patients need to be aware of the increased risks of revision with the various soft tissue allografts used for ACLR.

Analysis of 2019 Patients Undergoing Revision Anterior Cruciate Ligament Reconstruction From a Community-Based Registry

BACKGROUND

Knowledge of patient characteristics, surgical fixation, graft choice, outcomes, and concurrent injuries of revision anterior cruciate ligament reconstruction (ACLR) is limited.

PURPOSE

To describe the current cohort of revision ACLR captured by a community registry and the outcomes observed in the registered patients.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients who underwent revision ACLR registered between February 2005 and June 2014, by 200 surgeons in 46 hospitals, were evaluated. The Kaiser Permanente ACLR Registry (KPACLRR) collected data intraoperatively and postoperatively using paper forms, electronic medical records, administrative claims data, and patient-reported outcomes. The KPACLRR cohort was longitudinally followed, and outcomes were prospectively ascertained. Outcomes (ie, revisions, subsequent operative procedures, deep surgical site infections, and deep venous thrombosis) were adjudicated via a chart review. Descriptive statistics were employed.

RESULTS

Of 2019 patients who underwent revision ACLR, at a median follow-up of 2.2 years (interquartile range, 1.0-3.8 years), 212 (10.5%) required subsequent operative procedures, and 86 (4.3%) were revised a second time. At the time of revision, 55.1% of the patients had at least 1 concurrent meniscal injury, and 26% of those were repairable. Cartilage injuries were present in 42.0% of patients. Deep surgical site infections occurred in 12 patients (0.6%), deep venous thrombosis occurred in 5 patients (0.3%), and 1 patient (0.1%) had a pulmonary embolism.

CONCLUSION

Revision ACLR can be performed with a low short-term revision rate and relatively few complications. At the time of revision, nearly half of these patients had an irreparable meniscal injury, and slightly less than half had a cartilage injury. A large community-based ACLR registry is useful in informing surgeons of current treatment practices, prevalence of concurrent injuries, and outcomes associated with the procedures, especially infrequent procedures such as revision ACLR.

Increased Risk of Revision After Anterior Cruciate Ligament Reconstruction With Bone-Patellar Tendon-Bone Allografts Compared With Autografts

BACKGROUND

The use of allograft tissue for anterior cruciate ligament reconstruction (ACLR) remains controversial.

PURPOSE

To compare the risk of aseptic revision between bone-patellar tendon-bone (BPTB) autografts and BPTB allografts.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A retrospective cohort study of prospectively collected data was conducted using the Kaiser Permanente ACLR Registry. A cohort of patients who underwent primary unilateral ACLR with BPTB autografts and BPTB allografts was identified. Aseptic revision was the endpoint. The type of graft and allograft processing method (nonprocessed, <1.8-Mrad, and ≥1.8-Mrad irradiation) were the exposures of interest evaluated. Age (≤21 and ≥22 years) was evaluated as an effect modifier. Analyses were adjusted for age, sex, and race. Kaplan-Meier curves and Cox proportional hazards models were employed. Hazard ratios (HRs) and 95% CIs are provided.

RESULTS

The BPTB cohort consisted of 5586 patients: 3783 (67.7%) were male, 2359 (42.2%) were white, 1029 (18.4%) had allografts (nonprocessed: 155; <1.8 Mrad: 525; ≥1.8 Mrad: 288), and 4557 (81.6%) had autografts. The median age was 34.9 years (interquartile range [IQR], 25.4-44.0) for allograft cases and 22.0 years (IQR, 17.6-30.0) for autograft cases. The estimated cumulative revision rate at 2 years was 4.1% (95% CI, 2.9%-5.9%) for allografts and 1.7% (95% CI, 1.3%-2.2%) for autografts. BPTB allografts had a significantly higher adjusted risk of revision than BPTB autografts (HR, 4.54; 95% CI, 3.03-6.79; P < .001). This higher risk of revision was consistent with all allograft processing methods when compared with autografts and was also consistently higher in patients with allografts regardless of age.

CONCLUSION

When BPTB allograft tissue was used for ACLR, an overall 4.54 times adjusted higher risk of revision was observed compared with surgery performed with a BPTB autograft. Whether the tissue was irradiated with either high- or low-dose radiation, chemically processed, or not processed at all made little difference in the risk of revision. The differences in the revision risk were also consistent in younger and older patients. Surgeons and patients should be aware of the increased risk of revision when a BPTB allograft is used for ACLR.

Chronic Use of Opioids Before and After Total Knee Arthroplasty: A Retrospective Cohort Study

BACKGROUND

Opioids are commonly used for the management of preoperative and postoperative pain among patients undergoing total knee arthroplasty (TKA). There is limited literature on the chronic use of opioids pre-TKA and post-TKA. The aim of this study was to characterize the use of opioids in TKA patients before and after surgery and identify risk factors of chronic opioid use.

METHODS

Opioid use among 15,020 patients undergoing TKA (01/01/2001-31/12/2012) was examined. Generalized estimating equations assessed change in total oral morphine equivalents pre-TKA and post-TKA, and logistic regression estimated risk factors of chronic opioid use.

RESULTS

Of the total sample, 7782 (52.0%) patients had at least 1 opioid (38.6% pre-TKA and 34.4% post-TKA). The most commonly prescribed opioids were oxycodone, codeine + acetaminophen, and tramadol. Pre-TKA, 720 (4.8%) patients were chronic opioid users, of which 241 (33.5%) stopped being chronic users after surgery and 479 (66.5%) continued but had a 16% reduction (incidence rate ratio = 0.84; 95% confidence interval, 0.78-0.90) in total oral morphine equivalents. Of the 5077 (33.8%) occasional opioid user pre-TKA, 2407 (47.4%) stopped after surgery. Compared to nonopioid users, chronic users were younger, were female, had more comorbidity, and had longer hospital stays. Older age was associated with ceasing chronic opioid use post-TKA.

CONCLUSION

There was a reduction in opioid use following TKA. Almost 50% of occasional users and more than 30% of chronic users pre-TKA ceased opioids postoperatively. There was a reduction in use for those chronic users who continued to take opioids postsurgery.

Heart failure after conventional metal-on-metal hip replacements

Background and purpose - It is unclear whether metal particles and ions produced by mechanical wear and corrosion of hip prostheses with metal-on-metal (MoM) bearings have systemic adverse effects on health. We compared the risk of heart failure in patients with conventional MoM total hip arthroplasty (THA) and in those with metal-on-polyethylene (MoP) THA. Patients and methods - We conducted a retrospective cohort study using data from the Australian Government Department of Veterans' Affairs health claims database on patients who received conventional THA for osteoarthritis between 2004 and 2012. The MoM THAs were classified into groups: Articular Surface Replacement (ASR) XL Acetabular System, other large-head (LH) (> 32 mm) MoM, and small-head (SH) (≤ 32 mm) MoM. The primary outcome was hospitalization for heart failure after THA. Results - 4,019 patients with no history of heart failure were included (56% women). Men with an ASR XL THA had a higher rate of hospitalization for heart failure than men with MoP THA (hazard ratio (HR) = 3.2, 95% CI: 1.6-6.5). No statistically significant difference in the rate of heart failure was found with the other LH MoM or SH MoM compared to MoP in men. There was no statistically significant difference in heart failure rate between exposure groups in women. Interpretation - An association between ASR XL and hospitalization for heart failure was found in men. While causality between ASR XL and heart failure could not be established in this study, it highlights an urgent need for further studies to investigate the possibility of systemic effects associated with MoM THA.

An underlying diagnosis of osteonecrosis of bone is associated with worse outcomes than osteoarthritis after total hip arthroplasty

Background

Well-designed studies of complications and readmission rates in patients undergoing total hip arthroplasty (THA) with osteonecrosis are lacking. Our objective was to examine if a diagnosis of osteonecrosis was associated with complications, mortality and readmission rates after THA.

Methods

We analyzed prospectively collected data from an integrated healthcare system’s Total Joint Replacement Registry of adults with osteonecrosis vs. osteoarthritis (OA) undergoing unilateral primary THA during 2001–2012, in an observational cohort study. We examined mortality (90-day), revision (ever), deep (1 year) and superficial (30-day) surgical site infection (SSI), venous thromboembolism (VTE, 90-day), and unplanned readmission (90-day). Age, gender, race, body mass index, American Society of Anesthesiologists class, and diabetes were evaluated as confounders. We used logistic or Cox regression to calculate odds or hazard ratios (OR, HR) with 95% confidence intervals (CI).

Results

Of the 47,523 primary THA cases, 45,252 (95.2%) had OA, and 2,271 (4.8%) had osteonecrosis. Compared to the OA, patients with osteonecrosis were younger (median age 55 vs. 67 years), and were less likely to be female (42.5% vs. 58.3%) or White (59.8% vs. 77.4%). Compared to the OA, the osteonecrosis cohort had higher crude incidence of 90-day mortality (0.7% vs. 0.3%), SSI (1.2% vs. 0.8%), unplanned readmission (9.6% vs. 5.2%) and revision (3.1% vs. 2.4%). After multivariable-adjustment, patients with osteonecrosis had a higher odds/hazard of mortality (OR: 2.48; 95% CI:1.31–4.72), SSI (OR: 1.67, 95%CI:1.11–2.51), unplanned 90-day readmissions (OR: 2.20; 95% CI:1.67–2.91) and a trend towards higher revision rate 1-year post-THA (HR: 1.32; 95% CI: 0.94–1.84), than OA patients.

Conclusions

Compared to OA, a diagnosis of osteonecrosis was associated with worse outcomes post-THA. A detailed preoperative discussion including the risk of complications is needed for informed consent from patients with osteonecrosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1385-0) contains supplementary material, which is available to authorized users.

Surgical Technique Trends in Primary ACL Reconstruction from 2007 to 2014

BACKGROUND

The surgical technique for anterior cruciate ligament (ACL) reconstruction has evolved as a result of improved understanding of ligament biomechanics, anatomy, device development, and failed reconstructions. Studies on surgical technique preferences have been limited to surgeon surveys, which are subject to selection and recall bias. The purpose of this study was to evaluate ACL reconstruction surgical technique and yearly revision rate trends in a community-based setting.

METHODS

A population-based epidemiological study was conducted using data on primary ACL reconstruction procedures registered in an ACL reconstruction registry from 2007 to 2014. Changes in the incidence rates of different types of femoral tunnel drilling methods, different types of grafts and graft fixation, and revisions were studied. Adjusted incidence rate ratios (IRRs) are provided.

RESULTS

Of the 21,686 ACL reconstructions studied, 72.4% were performed by sports medicine fellowship-trained surgeons. The incidence rate of femoral tunnel drilling via a tibial tunnel decreased at an adjusted rate of 26% per year (IRR = 0.74, 95% confidence interval [CI] = 0.71 to 0.78), from 56.4% to 17.6% during the study period. The incidence rate of medial portal drilling increased from 41.3% to 65.1% at an adjusted rate of 11% per year (IRR = 1.11, 95% CI = 1.09 to 1.13), and the incidence rate of drilling through a lateral approach increased from 2.3% to 17.3% at an adjusted rate of 53% per year (IRR = 1.53, 95% CI = 1.39 to 1.67). There was no change in the use of hamstring autograft, bone-patellar tendon-bone autograft, or tibial tendon allograft. Use of first-generation bioabsorbable femoral and tibial fixation decreased for all graft types. For soft-tissue grafts, usage of suspensory metal femoral fixation increased 12% to 13% per year (IRR = 1.12, 95% CI = 1.09 to 1.15 for tibial tendon grafts; IRR = 1.13, 95% CI = 1.10 to 1.15 for hamstring grafts). For bone-patellar tendon-bone autografts, the use of femoral fixation with interference biocomposite screws increased 7% per year (IRR = 1.07, 95% CI = 1.04 to 1.10). On the tibial side, utilization of biocomposite screws increased for all graft types. No association was found between revision rate and the year of the primary operation.

CONCLUSIONS

Surgeons changed their femoral tunnel drilling technique over the study period, whereas the incidence rates of specific graft utilization remained stable. There has been a shift away from first-generation bioabsorbable fixation and increasing use of biocomposite fixation across all graft types. Early cumulative revision rates remained stable.

Total joint replacement: A multiple risk factor analysis of physical activity level 1-2 years postoperatively

Background and purpose - The effect of total joint arthroplasty (TJA) on physical activity is not fully understood. We investigated the change in physical activity after TJA and patient factors associated with change. Patients and methods - Using a total joint replacement registry, primary total hip arthroplasty (THA) patients (n = 5,678) and knee arthroplasty (TKA) patients (n = 11,084) between January 1, 2010 and December 31, 2012 were identified. Median age at THA was 68 and median age at TKA was 67. Change in self-reported physical activity (minutes per week) from before TJA (within 1 year of surgery) to after TJA (1-2 years) was the outcome of interest. Patient demographics and comorbidities were evaluated as risk factors. Multiple linear regression was used. Results - Median physical activity before surgery was 50 min/week (IQR: 0-140) for THA patients and 58 (IQR: 3-143) for TKA patients. Median physical activity after surgery was 150 min/week (IQR: 60-280) for both THA patients and TKA patients. Following TJA, 50% of patients met CDC/WHO physical activity guideline criteria. Higher body mass index was associated with lower change in physical activity (THA: -7.1 min/week; TKA: -5.9 min/week). Females had lower change than males (THA: -11 min/week; TKA: -9.1 min/week). In TKA patients, renal failure was associated with lower change (-17 min/week), as were neurological disorders (-30 min/week). Interpretation - Self-reported minutes of physical activity increased from before to after TJA, but 50% of TJA patients did not meet recommended physical activity guideline criteria. Higher body mass index, female sex, and specific comorbidities were found to be associated with low change in physical activity. Patient education on the benefits of physical activity should concentrate on these subgroups of patients.

Postoperative opioid use as an early indication of total hip arthroplasty failure

Background and purpose - A criticism of total hip arthroplasty (THA) survivorship analysis is that revisions are a late and rare outcome. We investigated whether prolonged opioid use is a possible indicator of early THA failure. Patients and methods - We conducted a cohort study of THAs registered in a total joint replacement registry from January 2008 to December 2011. 12,859 patients were evaluated. The median age was 67 years and 58% were women. Opioid use in the year after surgery was the exposure of interest, and the cumulative daily amounts of oral morphine equivalents (OMEs) were calculated. Post-THA OMEs per 90 day periods were categorized into quartiles. The endpoints were 1- and 5-year revisions. Results - After the first 90 days, 27% continued to use opioids. The revision rate was 0.9% within a year and 1.7% within 5 years. Use of medium-low (100-219 mg), medium-high (220-533 mg), and high (≥ 534 mg) amounts of OMEs in days 91-180 after surgery was associated with a 6 times (95% confidence interval (CI): 3-15), 5 times (CI: 2-13), and 11 times (CI: 2.9-44) higher adjusted risk of 1 year revision, respectively. The use of medium-low and medium-high amounts of OMEs in days 181-270 after surgery was associated with a 17 times (CI: 6-44) and 14 times (95% CI: 4-46) higher adjusted risk of 1-year revision. There was a similar higher risk of 5-year revision. Interpretation - Persistent postoperative use of opioids was associated with revision THA surgery in this cohort, and it may be an early indicator of potential surgical failures.

Risk factors for persistent and new chronic opioid use in patients undergoing total hip arthroplasty: a retrospective cohort study

OBJECTIVES

To determine chronic opioid use pre-THA (total hip arthroplasty) and post-THA, and risk factors for persistent or new chronic opioid use post-THA.

DESIGN

Retrospective cohort study.

SETTING

Australian Government Department of Veterans' Affairs health claims database.

PARTICIPANTS

9525 patients who had an elective unilateral THA between 1/01/2001 and 12/31/2012.

PRIMARY OUTCOME MEASURE

Chronic opioid use. Defined as 90 days of continuous opioid use or 120 days of non-continuous use.

RESULTS

Pre-THA, 6.2% (n=593) of patients were chronic users, while 5.2% (n=492) were post-THA. Among the 492 postoperative chronic users, 302 (61%) were chronic users pre-THA and post-THA and 190 (39%) became new chronic users after surgery. Risk factors for persistent chronic use were younger age (OR=0.96, 95% CI 0.93 to 0.99/1-year increment), back pain (OR=1.99, 95% CI 1.20 to 3.23), diabetes (OR=3.52, 95% CI 1.05 to 11.8), hypnotics use (OR=2.52, 95% CI 1.48 to 4.30) and higher pre-THA opioid exposure (compared with opioid use for 94-157 days, 157-224 days (OR=3.75, 95% CI 2.28 to 6.18), 225+ days (OR=5.18, 95% CI 2.92 to 9.19). Risk factors for new chronic opioid use post-THA were being a woman (OR=1.40, 95% CI 1.00 to 1.96), back pain (OR=3.90, 95% CI 2.85 to 5.33), depression (OR=1.70, 95% CI 1.20 to 2.41), gastric acid disease (OR=1.62, 95% CI 1.16 to 2.25), migraine (OR=5.11, 95% CI 1.08 to 24.18), liver disease (OR=4.33, 95% CI 1.08 to 17.35), weight loss (OR=2.60, 95% CI 1.06 to 6.39), dementia (OR=2.19, 95% CI 1.04 to 4.61), hyperlipidaemia (OR=1.38, 95% CI 1.00 to 1.91), hypnotics (OR=1.56, 95% CI 1.13 to 2.16) and antineuropathic pain medication use (OR=3.11, 95% CI 2.05 to 4.72).

CONCLUSIONS

Patients undergoing THA are exposed to opioids for long periods of time, putting them at high risk of harm related to opioid use. We identified groups at risk of chronic opioid use, including younger patients and women, as well as modifiable risk factors of chronic opioid use, including level of opioid exposure presurgery and hypnotic use. These indicators of chronic opioid use can be used by clinicians to target patient groups for suitable pain management interventions.

Opioid use after total hip arthroplasty surgery is associated with revision surgery

Background

Pain is an indication for total hip arthroplasty (THA) and it should be resolved post-surgery. Because patients’ pain is typically treated pharmacologically we tested whether opioid use can be used as a surrogate for patient-reported pain and as an indicator for early surgical failure. Specifically, we evaluated whether the amount of opioids taken within the year after THA was associated with one and five years risk of revision surgery.

Methods

A cohort of 9943 THAs (01/2001-12/2012) was evaluated. Post-operative opioid use was the exposure of interest and cumulative daily oral morphine equivalent (OME) amounts were calculated. Total OMEs/90-day periods were categorised into quartiles. Revisions within one and five years were the outcomes of interest.

Results

Of the THAs, 2.0 % (N = 200) were revised within one year and 4.2 % (N = 413) within five years. After adjustments for gender, age, surgical indication, co-morbidities, and other analgesics, revision was associated with amount of OMEs in the second quarter after THA (days 91–180 after discharge). Patients on medium-high amounts of OME (400-1119 mg) had higher risk of one (hazard ratio (HR) = 2.22, 95 % CI 1.08-4.56) and five year (HR = 1.66, 95 % CI 1.08-2.56) revision than a patient not taking opioids. During the same period, patients taking the highest amounts of OMEs (≥1120 mg) had a 2.64 (95 % CI 1.03-6.74) times higher risk of one year and a 2.11 (95 % CI 1.13-3.96) times higher risk of five year revision.

Conclusions

Opioid use 91–180 days post-surgery is associated with higher risk of revision surgery and therefore is an early and useful indicator for surgical failure.

Age-Related Risk Factors for Revision Anterior Cruciate Ligament Reconstruction: A Cohort Study of 21,304 Patients From the Kaiser Permanente Anterior Cruciate Ligament Registry

BACKGROUND

It is not clear whether risk factors for revision anterior cruciate ligament reconstruction (ACLR) are the same throughout patients' lives.

PURPOSE

To assess (1) the risk of revision ACLR by age and (2) age-specific risk factors for revision ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A cohort study using patients having undergone primary ACLR who were registered in the Kaiser Permanente ACLR Registry (February 2005 to June 2013) was conducted. Aseptic revision was the main endpoint. Age was evaluated as a risk factor for revision. The cohort was stratified into 4 age groups: <21, 21-30, 31-40, and >40 years. Graft type, sex, body mass index (BMI), and race were assessed as revision risk factors within each group. Survival analyses were conducted.

RESULTS

Of the 21,304 patients evaluated, 7026 (33%) patients were aged <21 years, 5762 (27%) were 21-30 years, 4656 (22%) were 31-40 years, and 3860 (18%) were >40 years. Allografts were used in 8671 (41%) patients, hamstring autografts in 6823 (32%), and bone-patellar tendon-bone (BPTB) autografts in 5260 (25%). The 5-year revision probability was highest in patients <21 years old (9.0%; 95% CI, 8.0%-10.1%) and lowest in those >40 years old (1.9%; 95% CI, 1.3%-2.7%). Compared with patients aged >40 years, the adjusted revision risk for patients aged <21 years was 7.76 (95% CI, 5.52-10.90). In patients aged <21 years, a lower revision risk was seen in female patients (hazard ratio [HR], 0.76; 95% CI, 0.61-0.93) compared with male patients, patients with a BMI of 30-35 kg/m(2) (HR, 0.75; 95% CI, 0.59-0.95) and BMI >35 kg/m(2) (HR, 0.49; 95% CI, 0.34-0.70) compared with those with a BMI <30 kg/m(2), and black patients (HR, 0.55, 95% CI, 0.36-0.85) compared with white patients. Sex, BMI, and race were not associated with the risk of revision in older patients. In patients ≤40 years old, those with allografts had a higher risk of revision than those with BPTB autografts (HR, 2.69, 2.35, and 3.04 for patients aged <21, 21-30, and 31-40 years, respectively). Patients <21 years old with hamstring autografts had a 1.61 times (95% CI, 1.20-2.17) higher risk of revision than did patients with BPTB autografts; these differences were not identified in older patients.

CONCLUSION

Age at the time of ACLR surgery is a strong risk factor for revision ACLR. Other risk factors for revision ACLR, such as graft type, sex, race, and BMI, may vary in strength and significance over a patient's life. Understanding the age-related risk factors associated with revision ACLR may help with appropriate patient counseling and optimal graft choice when performing ACLR.

Lower Total Knee Arthroplasty Revision Risk Associated With Bisphosphonate Use, Even in Patients With Normal Bone Density

BACKGROUND

Bisphosphonates (BPs) are associated with lower total knee arthroplasty (TKA) revision risk, but the effect of bone mineral density has not been evaluated.

METHODS

A cohort of 34,116 primary TKA patients was evaluated with revision surgery and periprosthetic fractures as end points. BP usage was the exposure of interest. Bone quality (normal, osteopenia, and osteoporosis) and patient age (<65 vs ≥65 years) were evaluated as effect modifiers of risk estimates.

RESULTS

Of the patients, 19.6% were BP users. In BP users, 0.5% underwent an aseptic revision; and 0.6%, a periprosthetic fracture. In non-BP users, 1.6% underwent aseptic revision; and 0.1%, a periprosthetic fracture.

CONCLUSION

Bisphosphonate use was associated with lower risk of revision in all bone quality categories in those older than 65 years. The risk of periprosthetic fractures was higher for patients on BP.

Antibiotic cement was associated with half the risk of re-revision in 1,154 aseptic revision total knee arthroplasties

BACKGROUND AND PURPOSE

Aseptic revisions comprise 80% of revision total knee arthroplasties (TKAs). We determined the incidence of re-revision TKA, the reasons for re-revision, and risk factors associated with these procedures.

PATIENTS AND METHODS

We conducted a retrospective cohort study of 1,154 patients who underwent aseptic revision TKA between 2002 and 2013 and were followed prospectively by a total joint replacement registry in the USA. Revision was defined as any operation in which an implanted component was replaced. Patient-, surgeon-, and procedure-related risk factors were evaluated. Survival analyses were conducted.

RESULTS

There were 114 re-revisions (10%) with a median time to reoperation of 3.6 years (interquartile range (IQR): 2.6-5.2). The infection rate was 2.9% (34/1,154) and accounted for 30% of re-revisions (34 of 114). In adjusted models, use of antibiotic-loaded cement was associated with a 50% lower risk of all-cause re-revision surgery (hazard ratio (HR) = 0.5, 95% CI: 0.3-0.9), age with a 20% lower risk for every 10-year increase (HR = 0.8, CI: 0.7-1.0), body mass index (BMI) with a 20% lower risk for every 5-unit increase (HR = 0.8, CI: 0.7-1.0), and a surgeon's greater cumulative experience (≥ 20 cases vs. < 20 cases) with a 3 times higher risk of re-revision (HR = 2.8, CI: 1.5-5).

INTERPRETATION

Revised TKAs were at high risk of subsequent failure. The use of antibiotic-loaded cement, higher age, and higher BMI were associated with lower risk of further revision whereas a higher degree of surgeon experience was associated with higher risk.

Similar mortality with general or regional anesthesia in elderly hip fracture patients

BACKGROUND AND PURPOSE

There is continuing confusion among practitioners with regard to the optimal choice of anesthetic type for repair of hip fractures. We investigated whether type of anesthetic was associated with short-term mortality after hip fracture surgery.

PATIENTS AND METHODS

We conducted a retrospective cohort study of patients with surgically treated hip fractures, performed between January 1, 2009 and December 31, 2012. Exposure of interest was anesthesia type (general, spinal/neuroaxial, and mixed). Endpoints were 30-, 90-, and 365-day post-surgery mortality. Multivariable conditional logistic regression models were used and odds ratios (ORs) and 95% confidence intervals (CIs) are reported.

RESULTS

Of the 7,585 participants, 5,412 (71%) were women and the median age was 80 (IQR: 72-85) years old. Of the total cohort, 4,257 (56%) received general anesthesia, 3,059 (40%) received spinal/neuroaxial, and 269 (4%) received mixed anesthesia. Overall, the incidence of 30-, 90-, and 365-day mortality was 4% (n = 307), 8% (n = 583), and 15% (n = 1,126), respectively. When compared with general anesthesia, the 365-day odds of mortality was marginally lower in patients with spinal/neuroaxial anesthesia (OR = 0.84, CI: 0.70-1.0), but it was similar in patients with mixed anesthesia (OR = 1.3, CI: 0.70-2.3). No other statistically significant differences were observed.

INTERPRETATION

Regarding mortality, this study does not support specific recommendations regarding the type of anesthetic in surgery of fractured hips.

Understanding Orthopaedic Registry Studies: A Comparison with Clinical Studies

Orthopaedic registries are valuable for monitoring patient outcomes in real-world settings. Registries are useful for identifying procedure incidence and device utilization, evaluating outcomes, determining patients at risk for complications and reoperations, identifying devices in recall situations, assessing comparative effectiveness of procedures and devices, and providing data for research studies. In the present report, we describe how orthopaedic registries can be used to conduct research and how they compare with randomized controlled trials (RCTs) in regard to methodology. Using an example, a comparison of the performance of mobile and fixed bearings in total knee arthroplasty, we evaluate the differences between, and the similarities of, RCTs and registry cohort studies with regard to how they are conducted and how their findings are reported. Orthopaedic registry studies differ from RCTs in many ways and offer certain advantages. The strengths and limitations of registry cohort studies and RCTs must be understood to properly evaluate the literature.

Understanding Orthopaedic Registry Studies: A Comparison with Clinical Studies

Orthopaedic registries are valuable for monitoring patient outcomes in real-world settings. Registries are useful for identifying procedure incidence and device utilization, evaluating outcomes, determining patients at risk for complications and reoperations, identifying devices in recall situations, assessing comparative effectiveness of procedures and devices, and providing data for research studies. In the present report, we describe how orthopaedic registries can be used to conduct research and how they compare with randomized controlled trials (RCTs) in regard to methodology. Using an example, a comparison of the performance of mobile and fixed bearings in total knee arthroplasty, we evaluate the differences between, and the similarities of, RCTs and registry cohort studies with regard to how they are conducted and how their findings are reported. Orthopaedic registry studies differ from RCTs in many ways and offer certain advantages. The strengths and limitations of registry cohort studies and RCTs must be understood to properly evaluate the literature.

Using Medications for Prediction of Revision after Total Joint Arthroplasty

This study evaluated the ability of a pharmacy based co-morbidity measure (RxRisk-V) to predict odds of one and five years revision in total hip arthroplasty (THA) and total knee arthroplasty (TKA) and compared its performance to the more commonly used co-morbidity measures in orthopaedics (Charlson and Elixhauser). 11,848 patients with THAs and 18,972 with TKAs performed between 2001 and 2012 were evaluated. Using a combination of conditions, identified by both the pharmacy and diagnoses based coding algorithms, models with acceptable predictive ability of THA and TKA revision were developed. These findings suggest prescription based co-morbidity measures can positively contribute to case-mix adjustment and outcome prediction in this patient population.

Risk calculators predict failures of knee and hip arthroplasties: findings from a large health maintenance organization

BACKGROUND

Considering the cost and risk associated with revision Total knee arthroplasty (TKAs) and Total hip arthroplasty (THAs), steps to prevent these operations will help patients and reduce healthcare costs. Revision risk calculators for patients may reduce revision surgery by supporting clinical decision-making at the point of care.

QUESTIONS/PURPOSES

We sought to develop a TKA and THA revision risk calculator using data from a large health-maintenance organization's arthroplasty registry and determine the best set of predictors for the revision risk calculator.

METHODS

Revision risk calculators for THAs and TKAs were developed using a patient cohort from a total joint replacement registry and data from a large US integrated healthcare system. The cohort included all patients who had primary procedures performed in our healthcare system between April 2001 and July 2008 and were followed until January 2014 (TKAs, n = 41,750; THAs, n = 22,721), During the study period, 9% of patients (TKA = 3066/34,686; THA=1898/20,285) were lost to followup and 7% died (TKA= 2350/41,750; THA=1419/20,285). The outcome of interest was revision surgery and was defined as replacement of any component for any reason within 5 years postoperatively. Candidate predictors for the revision risk calculator were limited to preoperative patient demographics, comorbidities, and procedure diagnoses. Logistic regression models were used to identify predictors and the Hosmer-Lemeshow goodness-of-fit test and c-statistic were used to choose final models for the revision risk calculator.

RESULTS

The best predictors for the TKA revision risk calculator were age (odds ratio [OR], 0.96; 95% CI, 0.95-0.97; p < 0.001), sex (OR, 0.84; 95% CI, 0.75-0.95; p = 0.004), square-root BMI (OR, 1.05; 95% CI, 0.99-1.11; p = 0.140), diabetes (OR, 1.32; 95% CI, 1.17-1.48; p < 0.001), osteoarthritis (OR, 1.16; 95% CI, 0.84-1.62; p = 0.368), posttraumatic arthritis (OR, 1.66; 95% CI, 1.07-2.56; p = 0.022), and osteonecrosis (OR, 2.54; 95% CI, 1.31-4.92; p = 0.006). The best predictors for the THA revision risk calculator were sex (OR, 1.24; 95% CI, 1.05-1.46; p = 0.010), age (OR, 0.98; 95% CI, 0.98-0.99; p < 0.001), square-root BMI (OR, 1.07; 95% CI, 1.00-1.15; p = 0.066), and osteoarthritis (OR, 0.85; 95% CI, 0.66-1.09; p = 0.190).

CONCLUSIONS

Study model parameters can be used to create web-based calculators. Surgeons can enter personalized patient data in the risk calculators for identification of risk of revision which can be used for clinical decision making at the point of care. Future prospective studies will be needed to validate these calculators and to refine them with time.

LEVEL OF EVIDENCE

Level III, prognostic study.

Does Racial Variation Influence Preoperative Characteristics and Intraoperative Findings in Patients Undergoing Anterior Cruciate Ligament Reconstruction?

BACKGROUND

A limited number of large multiethnic cohorts of patients undergoing anterior cruciate ligament reconstruction (ACLR) exist; therefore, little is known about racial differences in preoperative and intraoperative characteristics of patients undergoing this procedure.

PURPOSE

To evaluate preoperative patient, surgeon, and hospital characteristics and intraoperative findings associated with various patient races undergoing ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A cross-sectional study of patients undergoing primary ACLR (performed between January 1, 2008 and September 30, 2012) was conducted. The Kaiser Permanente ACLR Registry was used to identify the cases and variables for the study. The variables of age, sex, time from injury to surgery, body mass index, sport at the time of injury, concomitant injury (menisci, cartilage, other ligament), surgeon training, and surgeon and site volumes were evaluated. Race was categorized into white (reference), Hispanic, Asian, and black. Polychotomous regression models were employed. Odds ratios (ORs) and 95% CIs are provided.

RESULTS

A total of 14,278 ACLRs were evaluated; there were 7401 (51.8%) ACLRs performed on white, 3912 (27.4%) on Hispanic, 1894 (13.3%) on Asian, and 1071 (7.5%) on black patients. Men predominated overall as well as in each of the race categories. Compared with white patients, after adjusting for all covariates, Asian (OR, 1.24; 95% CI, 1.10-1.40) and Hispanic (OR, 1.52; 95% CI, 1.39-1.67) patients undergoing ACLR were more likely to be male than female, and black patients were more likely to be female (OR, 0.69; 95% CI, 0.60-0.80). All racial groups tended to undergo ACLR in younger age bands compared with white patients, with black patients having the highest odds of being < 17 years (OR, 2.74; 95% CI, 2.23-3.37) and 17 to 24 years of age (OR, 2.28; 95% CI, 1.94-2.68) compared with being ≥ 25 years. Asian patients were more likely injured playing basketball (OR, 4.31; 95% CI, 3.67-5.06), black patients during football (OR, 3.48; 95% CI, 2.73-4.45) and basketball (OR, 5.52; 95% CI, 4.49-6.78), and Hispanic patients during soccer (OR, 3.09; 95% CI, 2.75-3.48). Hispanic patients had a higher likelihood of having both menisci injured at the time of surgery (OR, 1.31; 95% CI, 1.16-1.49) as well as the lateral meniscus (OR, 1.31; 95% CI, 1.17-1.47). Asian patients had a lower likelihood of cartilage injuries (OR, 0.78; 95% CI, 0.68-0.88). Sports medicine fellowship-trained surgeons were more likely to have operated on black (OR, 1.27; 95% CI, 1.07-1.51) and Hispanic (OR, 1.16; 95% CI, 1.04-1.29) patients.

CONCLUSION

In this large representative sample of patients undergoing ACLR in the United States, 48.2% of the cohort was nonwhite, and racial variations in sex, age, sport at injury, and intraoperative findings at ACLR were identified. Understanding the differences in ACL injury presentation and concomitant injuries by race can be useful in helping tailor the development of an ACL injury prevention program, during the informed consent process, and in the arthroscopic portion of the procedure according to patient race-specific characteristics.

Are There Modifiable Risk Factors for Hospital Readmission After Total Hip Arthroplasty in a US Healthcare System?

BACKGROUND

Although total hip arthroplasty (THA) is a successful procedure, 4% to 11% of patients who undergo THA are readmitted to the hospital. Prior studies have reported rates and risk factors of THA readmission but have been limited to single-center samples, administrative claims data, or Medicare patients. As a result, hospital readmission risk factors for a large proportion of patients undergoing THA are not fully understood.

QUESTIONS/PURPOSES

(1) What is the incidence of hospital readmissions after primary THA and the reasons for readmission? (2) What are the risk factors for hospital readmissions in a large, integrated healthcare system using current perioperative care protocols?

METHODS

The Kaiser Permanente (KP) Total Joint Replacement Registry (TJRR) was used to identify all patients with primary unilateral THAs registered between January 1, 2009, and December 31, 2011. The KPTJRR's voluntary participation is 95%. A logistic regression model was used to study the relationship of risk factors (including patient, clinical, and system-related) and the likelihood of 30-day readmission. Readmissions were identified using electronic health and claims records to capture readmissions within and outside the system. Odds ratio (OR) and 95% confidence intervals (CIs) were calculated. Of the 12,030 patients undergoing primary THAs included in the study, 59% (n = 7093) were women and average patient age was 66.5 years (± 10.7).

RESULTS

There were 436 (3.6%) patients with hospital readmissions within 30 days of the index procedure. The most common reasons for readmission were infection and inflammatory reaction resulting from internal joint prosthetic (International Classification of Diseases, 9(th) Revision, Clinical Modification [ICD-9-CM] 996.66, 7.0%); other postoperative infection (ICD-9-CM 998:59, 5.5%); unspecified septicemia (ICD-9-CM 038.9, 4.9%); and dislocation of a prosthetic joint (ICD-9-CM 996.42, 4.7%). In adjusted models, the following factors were associated with an increased likelihood of 30-day readmission: medical complications (OR, 2.80; 95% CI, 1.59-4.93); discharge to facilities other than home (OR, 1.89; 95% CI, 1.39-2.58); length of stay of 5 or more days (OR, 1.80; 95% CI, 1.22-2.65) versus 3 days; morbid obesity (OR, 1.74; 95% CI, 1.25-2.43); surgeries performed by high-volume surgeons compared with medium volume (OR, 1.53; 95% CI, 1.14-2.08); procedures at lower-volume (OR, 1.41; 95% CI, 1.07-1.85) and medium-volume hospitals (OR, 1.81; 95% CI, 1.20-2.72) compared with high-volume ones; sex (men: OR, 1.51; 95% CI, 1.18-1.92); obesity (OR, 1.32; 95% CI, 1.02-1.72); race (black: OR, 1.26; 95% CI, 1.02-1.57); increasing age (OR, 1.03; 95% CI, 1.01-1.04); and certain comorbidities (pulmonary circulation disease, chronic pulmonary disease, hypothyroidism, and psychoses).

CONCLUSIONS

The 30-day hospital readmission rate after primary THA was 3.6%. Modifiable factors, including obesity, comorbidities, medical complications, and system-related factors (hospital), have the potential to be addressed by improving the health of patients before this elective procedure, patient and family education and planning, and with the development of high-volume centers of excellence. Nonmodifiable factors such as age, sex, and race can be used to establish patient and family expectations regarding risk of readmission after THA. Contrary to other studies and the finding of increased hospital volume associated with lower risk of readmission, higher volume surgeons had a higher risk of patient readmission, which may be attributable to the referral patterns in our organization.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Anterior and Anterolateral Approaches for THA Are Associated With Lower Dislocation Risk Without Higher Revision Risk

BACKGROUND

Lack of consensus continues regarding the benefit of anteriorly based surgical approaches for primary total hip arthroplasty (THA). The purpose of this study was to evaluate the risk of aseptic revision, septic revision, and dislocations for various approaches used in primary THAs from a community-based healthcare organization.

QUESTIONS/PURPOSES

(1) What is the incidence of aseptic revision, septic revision, and dislocation for primary THA in a large community-based healthcare organization? (2) Does the risk of aseptic revision, septic revision, and dislocation vary by THA surgical approach?

METHODS

The Kaiser Permanente Total Joint Replacement Registry was used to identify primary THAs performed between April 1, 2001 and December 31, 2011. Endpoints were septic revisions, aseptic revisions, and dislocations. The exposure of interest was surgical approach (posterior, anterolateral, direct lateral, direct anterior). Patient, implant, surgeon, and hospital factors were evaluated as possible confounders. Survival analysis was performed with marginal multivariate Cox models. Hazard ratios (HRs) and 95% confidence intervals (CIs) are reported. A total of 42,438 primary THAs were available for analysis of revision outcomes and 22,237 for dislocation. Median followup was 3 years (interquartile range, 1-5 years). The registry's voluntary participation is 95%. The most commonly used approach was posterior (75%, N = 31,747) followed by anterolateral (10%, N = 4226), direct anterior (4%, N = 1851), and direct lateral (2%, N = 667).

RESULTS

During the study period 785 hips (2%) were revised for aseptic reasons, 213 (0.5%) for septic reasons, and 276 (1%) experienced a dislocation. The revision rate per 100 years of observation was 0.54 for aseptic revisions, 0.15 for septic revisions, and 0.58 for dislocations. There were no differences in adjusted risk of revision (either septic or aseptic) across the different THA approaches. However, the anterolateral approach (adjusted HR, 0.29; 95% CI, 0.13-0.63, p = 0.002) and direct anterior approach (adjusted HR, 0.44; 95% CI, 0.22-0.87, p = 0.017) had a lower risk of dislocation relative to the posterior approach. There were no differences in any of the outcomes when comparing the direct anterior approach with the anterolateral approach.

CONCLUSIONS

Anterior and anterolateral surgical approaches had the advantage of a lower risk of dislocation without increasing the risk of early revision.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Predicting Infections After Total Joint Arthroplasty Using a Prescription Based Comorbidity Measure

This study evaluated the association and predictive ability of co-morbidities measured by RxRisk-V, Elixhauser and Charlson measures and post-total hip (THA) and total knee arthroplasties (TKA) infection. THAs and TKAs (2001-2012) were identified using the Australian Department of Veterans' Affairs data. Infections within 90 days post-surgery were the study endpoint. Co-morbidities were identified using pharmacy (RxRisk-V) and hospitalization history (Elixhauser, Charlson). Of the 11,848 THAs, 3.1% (N = 364) had infections and out of 18,972 TKAs 3.4% (N = 648). Comorbidity burden and specific conditions were associated with infection likelihood. RxRisk-V performed better than other measures, but none had high predictive ability and differences were small. The best performing infection prediction models resulted when a combination of conditions identified by all measures was used.

Are Nonagenarians Too Old For Total Hip Arthroplasty? An Evaluation of Morbidity and Mortality Within a Total Joint Replacement Registry

A greater number of patients aged 90 and over will become candidates for total hip arthroplasty (THA) as the nonagenarian population continues to grow. This study evaluated the patient characteristics and incidence of postoperative morbidity and mortality of 183 nonagenarian THA patients among 43,543 primary THA patients followed by a total joint replacement registry. Nonagenarians had a greater number of comorbidities preoperatively, experienced a higher one year mortality and had a longer hospital length of stay. However, nonagenarians did not have an increased risk of infection, deep vein thrombosis or pulmonary embolism and postoperative mortality was within expected rates for individuals 90 years and older. Higher readmission rates, however, highlight the benefits of close follow up during a prolonged postoperative period.

A Community-Based Hip Fracture Registry: Population, Methods, and Outcomes

Cases of hip fracture recorded from 1/2009 to 12/2011 were ascertained using the Kaiser Permanente Hip Fracture Registry. The registry collects information on patient, procedure, surgeon, facility, and surgical outcomes. The population (N = 12,562) was predominantly white, women, and older (≥ 75 years), and 32% had at least 5 comorbidities. The average length of follow-up was 1.1 years. Hemiarthroplasty was the most common procedure (33.1%). Most fractures were treated by medium-volume surgeons at high-volume facilities. The 90-day readmission rate was 22.1%, and the mortality rate was 12.3%.

Comparison of paper and electronic surveys for measuring patient-reported outcomes after anterior cruciate ligament reconstruction

OBJECTIVE

This study compared response rates of paper and electronic versions of the Knee injury Osteoarthritis and Outcome Score questionnaire and examined the characteristics of patients who responded to each survey method.

METHODS

A total of 1486 patients registered by the Kaiser Permanente Anterior Cruciate Ligament Reconstruction Registry between 2005 and 2010 were included in this study. Response rates by survey modality for the overall cohort, by the specific time periods, and by age and sex at time of anterior cruciate ligament reconstruction were compared using χ(2) tests or the Fisher exact test when appropriate. Independent Student t tests were used to compare the Knee injury Osteoarthritis and Outcome Scores of survey respondents.

RESULTS

The overall survey response rate was 42%. The 36% response rate in the electronic-survey group was significantly higher than the 22% response rate in the paper-survey group (p < 0.001). The electronic response rate was also significantly higher than the paper response rate at all follow-up times (35% vs 25% at 1 year, p = 0.004, 38% vs 20% at 2 years, p < 0.001, and 35% vs 21% at 3 years; p < 0.001) and among all age groups 19 years and older.

CONCLUSION

Although the electronic survey produced higher response rates, it is not sufficient alone to replace the traditional paper version among this Kaiser Permanente population.

Two-Day Length of Stay is Not Inferior to 3 Days in Total Knee Arthroplasty with Regards to 30-Day Readmissions

The impact of a shortened length of stay (LOS) following total knee arthroplasty (TKA) on the risk of readmission is not well documented despite recent trends towards shorter hospitalization. We retrospectively compared the adjusted risk of 30-day readmission following TKA between patients with 2-, 3- and 4-day LOS using current postoperative care protocols. A total of 23,655 consecutive primary, unilateral TKAs operated between 01/01/2009 and 12/31/2011 were studied retrospectively using non-inferiority testing. The main outcome was 30-day readmission. Two-day LOS decreased the odds of readmission by a factor of 0.96, with an upper bound one-sided 95% confidence interval of 1.10. After adjusting for other variables, LOS of 2 days is not inferior to 3 days with respect to the risk of 30-day readmission.

Revision total hip arthoplasty: factors associated with re-revision surgery

BACKGROUND

The survivorship of implants after revision total hip arthroplasty and risk factors associated with re-revision are not well defined. We evaluated the re-revision rate with use of the institutional total joint replacement registry. The purpose of this study was to determine patient, implant, and surgeon factors associated with re-revision total hip arthroplasty.

METHODS

A retrospective cohort study was conducted. The total joint replacement registry was used to identify patients who had undergone revision total hip arthroplasty for aseptic reasons from April 1, 2001, to December 31, 2010. The end point of interest was re-revision total hip arthroplasty. Risk factors evaluated for re-revision total hip arthroplasty included: patient risk factors (age, sex, body mass index, race, and general health status), implant risk factors (fixation type, bearing surface, femoral head size, and component replacement), and surgeon risk factors (volume and experience). A multivariable Cox proportional hazards model was used.

RESULTS

Six hundred and twenty-nine revision total hip arthroplasties with sixty-three (10%) re-revisions were evaluated. The mean cohort age (and standard deviation) was 57.0 ± 12.4 years, the mean body mass index (and standard deviation) was 29.5 ± 6.1 kg/m(2), and most of the patients were women (64.5%) and white (81.9%) and had an American Society of Anesthesiologists score of <3 (52.9%). The five-year implant survival after revision total hip arthroplasty was 86.8% (95% confidence interval, 83.57% to 90.25%). In adjusted models, age, total number of revision surgical procedures performed by the surgeon, fixation, and bearing surface were associated with the risk of re-revision. For every ten-year increase in patient age, the hazard ratio for re-revision decreases by a factor of 0.72 (95% confidence interval, 0.58 to 0.90). For every five revision surgical procedures performed by a surgeon, the risk of revision decreases by a factor of 0.93 (95% confidence interval, 0.86 to 0.99). At the time of revision, a new or retained cemented femoral implant or all-cemented hip implant increases the risk of revision by a factor of 3.19 (95% confidence interval, 1.22 to 8.38) relative to a retained or new uncemented hip implant. A ceramic on a highly cross-linked polyethylene bearing articulation decreases the hazard relative to metal on highly cross-linked polyethylene by a factor of 0.32 (95% confidence interval, 0.11 to 0.95). Metal on constrained bearing increases the hazard relative to metal on highly cross-linked polyethylene by a factor of 3.32 (95% confidence interval, 1.16 to 9.48).

CONCLUSIONS

When evaluating patient, implant, and surgical factors at the time of revision total hip arthroplasty, age, surgeon experience, implant fixation, and bearing surfaces had significant impacts on the risk of re-revision.

Metal-on-conventional polyethylene total hip arthroplasty bearing surfaces have a higher risk of revision than metal-on-highly crosslinked polyethylene: results from a US registry

BACKGROUND

Although studies have reported lower radiological wear in highly crosslinked polyethylene (HXLPE) versus conventional polyethylene in total hip arthroplasty (THA), there is limited clinical evidence on the risk of revision of these polyethylene THA bearing surfaces.

QUESTIONS/PURPOSES

We asked: (1) Do primary THAs with a metal-on-conventional polyethylene bearing surface have a higher risk of revision (all-cause or aseptic) than metal-on-HXLPE? (2) Is the risk of revision (all-cause or aseptic) higher for conventional polyethylene versus HXLPE when the effect of femoral and acetabular components is controlled for in prosthesis-specific analyses?

METHODS

The Kaiser Permanente's Total Joint Replacement Registry was used to identify metal-on-conventional polyethylene and metal-on-HXLPE primary THAs (N = 26,823) performed between April 2001 and December 2011. The registry has 95% voluntary participation and 8% were lost to followup during the 10-year study period. Endpoints of interest were all-cause and aseptic revisions. Descriptive statistics and marginal Cox regression models with propensity score adjustments were applied to compare risk of revision for metal-on-conventional polyethylene versus metal-on-HXLPE THAs and to evaluate two specific manufacturers' hip implant designs while controlling for femoral and acetabular components. Of the 26,823 THAs included in the study, 1815 (7%) were metal-on-conventional polyethylene and 25,008 (93%) were metal-on-HXLPE.

RESULTS

At 7 years followup, the cumulative incidence of revision was 5.4% (95% confidence interval [CI], 4.4%-6.7%) for metal-on-conventional and 2.8% (95% CI, 2.6%-3.2%) for metal-on-HXLPE. There was a higher adjusted risk of all-cause (hazard ratio [HR], 1.75; 95% CI, 1.37-2.24; p < 0.001) and aseptic (HR, 1.91; 95% CI, 1.46-2.50; p < 0.001) revisions among metal-on-conventional polyethylene bearing surface hips compared with metal-on-HXLPE. Results were similar within manufacturer hip designs with the same femoral and acetabular components. Conclusions Metal-on-conventional polyethylene THA bearing surfaces have a higher risk of revision compared with metal-on-HXLPE bearing surfaces. Clinicians should consider the use of HXLPE when using a polyethylene bearing in THA.

LEVEL OF EVIDENCE

Level II, cohort study.

Risk factors associated with revision and contralateral anterior cruciate ligament reconstructions in the Kaiser Permanente ACLR registry

BACKGROUND

Patients generally choose to undergo anterior cruciate ligament reconstruction (ACLR) to return to their active lifestyles. However, returning to their previous activity level may result in a retear of their reconstructed knee or an injury to their contralateral anterior cruciate ligament (CACL).

PURPOSE

To determine the risk factors associated with revision ACLR and contralateral ACLR (CACLR), compare the survival of the reconstructed ACL with the CACL, and determine how the risk factors associated with revision ACLR compare with those for CACLR.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective cohort study of prospectively collected data from the Kaiser Permanente ACLR registry between February 1, 2005, and September 30, 2012, was conducted. Primary ACLR cases without history of contralateral knee ACL injury were included. The study endpoints included revision ACLR and CACLR. Graft type (bone-patellar tendon-bone [BPTB] autograft, hamstring autograft, and allograft) was the main exposure of interest, and patient characteristics were evaluated as risk factors for revision ACLR and CACLR. Survival analyses were conducted.

RESULTS

A total of 17,436 ACLRs were evaluated. The median age was 27.2 years (interquartile range, 18.7-37.7 years), and 64% were males. The 5-year survival for index ACLR was 95.1% (95% CI, 94.5%-95.6%), and for CACL it was 95.8% (95% CI, 95.2%-96.3%). Overall, the cohort had a mean of 2.4 ± 1.7 years of follow-up; 18.2% were lost to follow-up. There were fewer CACLRs per 100 years of observation (0.83) than there were revision ACLRs (1.05) during the study period (P < .001). There was a statistically significant difference in the density of revision ACLR and CACL in BPTB autografts (0.74 vs 1.06, respectively; P = .010), hamstring autografts (1.07 vs 0.81; P = .042), and allografts (1.26 vs 0.67; P < .001). The risk factors for revision ACLR and contralateral surgery were different (P < .05). After adjusting for covariates, factors associated with higher risk of revision ACLR were as follows: allografts, hamstring autografts, male sex, younger age, lower body mass index (BMI), and being white as opposed to black. Factors associated with higher risk of CACLR were as follows: younger age, female sex, and lower BMI.

CONCLUSION

The 5-year revision-free and CACLR-free survival rate in this study was 95.1% and 95.8%, respectively. Allografts and hamstring autografts had a higher risk of revision ACLR surgery, and BPTB autografts had a higher risk of CACLR. Males were found to have a higher risk of revision ACLR, and females had a higher risk of CACLR. Increasing age and increasing BMI decreased the risk of both revision and CACLR.

Leveraging Electronic Medical Records for Surveillance of Surgical Site Infection in a Total Joint Replacement Population

Objective.

TO evaluate whether a hybrid electronic screening algorithm using a total joint replacement (TJR) registry, electronic surgical site infection (SSI) screening, and electronic health record (EHR) review of SSI is sensitive and specific for SSI detection and reduces chart review volume for SSI surveillance.

Design.

Validation study.

Setting.

A large health maintenance organization (HMO) with 8.6 million members.

Methods.

Using codes for infection, wound complications, cellullitis, procedures related to infections, and surgeon-reported complications from the International Classification of Diseases, Ninth Revision, Clinical Modification, we screened each TJR procedure performed in our HMO between January 2006 and December 2008 for possible infections. Flagged charts were reviewed by clinical-content experts to confirm SSIs. SSIs identified by the electronic screening algorithm were compared with SSIs identified by the traditional indirect surveillance methodology currently employed in our HMO. Positive predictive values (PPVs), negative predictive values (NPVs), and specificity and sensitivity values were calculated. Absolute reduction of chart review volume was evaluated.

Results.

The algorithm identified 4,001 possible SSIs (9.5%) for the 42,173 procedures performed for our TJR patient population. A total of 440 case patients (1.04%) had SSIs (PPV, 11.0%; NPV, 100.0%). The sensitivity and specificity of the overall algorithm were 97.8% and 91.5%, respectively.

Conclusion.

An electronic screening algorithm combined with an electronic health record review of flagged cases can be used as a valid source for TJR SSI surveillance. The algorithm successfully reduced the volume of chart review for surveillance by 90.5%.

Mortality after shoulder arthroplasty

One year post-operative mortality among patients with primary elective total shoulder arthroplasty (ETSA) and traumatic shoulder arthroplasty (TSA) were compared to the general population of a large healthcare system. Standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) were calculated. 614 ETSA patients, 1.0% one year mortality, and 168 TSA patients, 5.4% mortality rate, were evaluated. Patients with ETSA (SMR = 0.4, 95% CI 0.1-0.7) had lower odds of mortality than expected, while patients with TSA (SMR = 1.8, 95% CI 0.6-3.0) did not have higher than expected odds of mortality compared to the reference population. Understanding excess mortality following shoulder arthroplasty surgery allows providers to evaluate current practices and identify ways to optimize patients prior to surgery.