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.