Every month, JBJS publishes a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Click here for a collection of OrthoBuzz summaries of these “What’s New” articles. This month, author Michael J. Taunton, MD selected the 5 most clinically compelling findings from the more than 130 studies summarized in the January 15, 2020 “What’s New in Adult Reconstructive Knee Surgery.”
Unicompartmental Knee Arthroplasty (UKA)
—A prospective cohort study of 1,000 Oxford cementless UKAs indicated by standard Kozinn and Scott criteria found that revision-free survivorship at 10 years was 97%. Progression of lateral osteoarthritis and dislocation of the bearing were the most common reasons for revision.1
—Authors of a double-blinded, prospective, randomized study assigned 60 primary total knee arthroplasty (TKA) patients to receive either a continuous adductor canal block or a single-injection adductor canal block with adjuvant agents. They found no between-group differences in pain scores up to 42 hours postoperatively.2
Post-TKA Physical Therapy (PT)
—A prospective, randomized, noninferiority trial demonstrated that 290 post-TKA patients who were randomized to either outpatient PT, unsupervised web-based PT at home, or unsupervised printed-instruction-based PT at home had no difference in knee range of motion or in patient-reported outcomes at 4 to 6 weeks or 6 months postoperatively.3
—In a retrospective review of 29,695 total joint arthroplasties, preoperative penicillin allergy testing led to a 1.19% higher rate of infection-free survival at 10 years, principally by allowing more routine use of the prophylactic antibiotic cefazolin.4
—A retrospective case series found that patients undergoing revision TKA at an age of < 50 years had a survivorship free of re-revision of 66% at 10 years. Regardless of the reason for revision, this population also had a higher risk of mortality than the general population at 10 years.5
- Campi S, Pandit H, Hooper G, Snell D, Jenkins C, Dodd CAF, et al. Ten-year survival and seven-year functional results of cementless Oxford unicompartmental knee replacement: A prospective consecutive series of our first 1000 cases. Knee. 2018 Dec;25(6):1231-7. Epub 2018/08/29.
- Turner JD, Dobson SW, Henshaw DS, Edwards CJ, Weller RS, Reynolds JW, et al. Single-Injection Adductor Canal Block With Multiple Adjuvants Provides Equivalent Analgesia When Compared With Continuous Adductor Canal Blockade for Primary Total Knee Arthroplasty: A Double-Blinded, Randomized, Controlled, Equivalency Trial. J Arthroplasty. 2018 Oct;33(10):3160-6 e1. Epub 2018/06/16.
- Fleischman AN, Crizer MP, Tarabichi M, Smith S, Rothman RH, Lonner JH, et al. 2018 John N. Insall Award: Recovery of Knee Flexion With Unsupervised Home Exercise Is Not Inferior to Outpatient Physical Therapy After TKA: A Randomized Trial. Clin Orthop Relat Res. 2019 Jan;477(1):60-9. Epub 2019/02/23.
- Wyles CC, Hevesi M, Osmon DR, Park MA, Habermann EB, Lewallen DG, et al. 2019 John Charnley Award: Increased risk of prosthetic joint infection following primary total knee and hip arthroplasty with the use of alternative antibiotics to cefazolin: the value of allergy testing for antibiotic prophylaxis. Bone Joint J. 2019 Jun;101-B(6_Supple_B):9-15. Epub 2019/05/31.
- Chalmers BP, Pallante GD, Sierra RJ, Lewallen DG, Pagnano MW, Trousdale RT. Contemporary Revision Total Knee Arthroplasty in Patients Younger Than 50 Years: 1 in 3 Risk of Re-Revision by 10 Years. J Arthroplasty. 2019 Jul;34(7S):S266-S70. Epub 2019/03/03.
In March 2019, OrthoBuzz covered a JBJS study by Rudasill et al. that found a progressively increasing risk of bleeding requiring transfusion among total knee arthroplasty (TKA) patients who had a preoperative International Normalized Ratio (INR) >1. (INR is a standardized measure of how long it takes blood to clot—the higher the number, the longer the clotting time.) These authors also found a significantly increased risk of infection in TKA patients with INR >1.5. and an increased risk of mortality within 30 days of surgery among those with an INR >1.25 to 1.5.
In the January 2, 2020 issue of JBJS, the same team of researchers report findings from a similarly designed NSQIP-based study of patients undergoing total hip arthroplasty (THA). The authors evaluated data from >17,500 patients who underwent a primary THA between 2005 and 2016 and who also had an INR value documented within 2 days prior to joint replacement. Rudasill et al. stratified these patients into 4 groups based on preoperative INRs: ≤1, >1 to <1.25, 1.25 to <1.5, and ≥1.5).
After adjustment, the authors found a significant, independent effect between increased preoperative INR and increased bleeding requiring transfusion and mortality. Specifically, bleeding risk became evident at INR ≥1.25, and patients with INR ≥1.5 were at a significantly increased risk of mortality. The length of hospital stay also increased significantly as INR class increased.
The authors suggest that “current INR targeting [INR <1.5 for elective orthopaedic surgery] may not be strict enough to minimize adverse outcomes for patients undergoing primary total hip arthroplasty.” While admitting that these findings are not likely to change the day-to-day practice of orthopaedic surgeons, the authors say they “may influence preoperative risk stratification for those patients with elevated INR.”
Among the elderly, low-energy hip fractures are common injuries that almost all orthopaedic surgeons encounter. While operative management is typically the standard of care, there are some patients for whom nonoperative treatment is most aligned with their goals of care, usually because of chronic disease, fragility, and/or high risk of perioperative mortality.
When counseling elderly patients and family members about the risks and benefits of surgical management for a hip fracture, we have abundant data. We can estimate the length of rehabilitation, discuss the likelihood of regaining independence with ambulation, and quote the 30-day, 1-year, and 5-year mortality statistics. But what about the risks and benefits of nonoperative care? How long do these patients live? How many are alive 1 year after the fracture?
Chlebeck and colleagues attempt to answer those questions with a retrospective cohort study of 77 hip fracture patients who were treated nonoperatively and a matched cohort of 154 operatively treated hip fracture patients. Nonoperative management was chosen only after a palliative-care consult was obtained and after a thorough multidisciplinary discussion of treatment goals with the patient and family. Patients who elected nonoperative care were treated with early limited weight bearing and a focus on maximizing comfort. Researchers established a comparative operative cohort through 2:1 matched pairing, controlling for age, sex, fracture type, Charlson Comorbidity Index, preinjury living situation, preinjury ambulatory status, and presence of dementia and cardiac arrhythmia.
As one might expect, there was significantly lower mortality in the operative group. The in-hospital, 30-day, and 1-year mortality for nonoperatively treated patients was 28.6%, 63.6%, and 84.4% respectively. The mortality rates seen in the operative cohort were 3.9%, 11.0%, and 36.4% respectively. A Kaplan-Meier survival analysis revealed the median life expectancy in the nonoperative cohort to be 14 days, versus 839 days in the operative group (p <0.0001). Interestingly, the researchers found no difference in hospital length of stay between the two groups (5.4 vs. 7.7 days; p=0.10).
These results provide useful references for orthopedic surgeons to use when counseling hip fracture patients and their families. Surgical intervention remains the standard of care in most instances, and this study suggests that operative care offers a significant mortality benefit over nonoperative care even in relatively unhealthy patients, like those selected for the matched operative cohort.
This study also gives us data to help guide the expectations of patients who decide surgery is not in line with their wishes. Half of the patients who elected nonoperative care in this study died within 14 days of admission, and only 15.6% were still alive at 1 year. Additionally, choosing nonoperative care does not lengthen hospitalization, suggesting that these patients can be quickly transferred to a more comfortable setting.
Matthew Herring, MD is a fellow in orthopaedic trauma at the University of California, San Francisco and a member of the JBJS Social Media Advisory Board.
An elevated International Normalized Ratio (INR)—a standardized gauge for how long it takes blood to clot—is rarely a good sign when someone is about to undergo an elective orthopaedic procedure. This is especially true for larger surgeries such as total hip or knee arthroplasty, in which there are already concerns about perioperative bleeding. Excessive surgery-related blood loss can lead to wound complications, increased length of hospital stay, and higher mortality rates. But what precisely constitutes an “elevated” INR? While some recommendations suggest that elective procedures be performed only when a patient’s INR is ≤1.5, the evidence supporting this recommendation, especially in the setting of total knee arthroplasty (TKA), is sparse at best.
In the March 20, 2019 issue of The Journal, Rudasill et al. use the National Surgical Quality Improvement Program (NSQIP) database to help define what “elevated” should mean in the context of TKA. They evaluated data from >21,000 patients who underwent a TKA between 2010 and 2016 and who also had an INR level reported within one day before their joint replacement. They stratified these patients based on their INR levels (≤1, >1 to 1.25, >1.25 to 1.5, and >1.5). Using multivariate regression analysis to adjust for patient demographics and comorbidities, the authors found a progressively increasing risk of bleeding requiring transfusion for each group with an INR >1 (odds ratios of 1.19, 1.29 and 2.02, respectively). Relative to patients with an INR of ≤1, Rudasill et al. also found a significantly increased risk of infection in TKA patients with an INR >1.5 (odds ratio 5.34), and an increased risk of mortality within 30 days of surgery among patients with an INR >1.25 to 1.5 (odds ratio 3.37). Lastly, rates of readmission and the length of stay were significantly increased in patients with an INR >1.25.
While there are certainly weaknesses inherent in using the NSQIP dataset, this study is the first to carefully evaluate the impact of slight INR elevations on post-TKA morbidity and mortality. While I was not surprised that increasing INR levels were associated with increased bleeding events, I was impressed by the profound differences in length of stay, infection, and mortality between patients with an INR ≤1 and those with an INR >1.25. I agree with the authors’ conclusion that “current guidelines for a target INR of <1.5 should be reconsidered for patients undergoing TKA.” Further, based on the risks highlighted in this study, prospective or propensity matched cohort studies should be performed to help determine whether anyone with an INR >1 should undergo a TKA.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
Any patient presenting with a spinal epidural abscess is in a high-risk situation, but decisions about operative versus nonoperative management in such cases are influenced largely by the presence, absence, or imminent risk of a motor deficit. This is why the identification by Shah et al. of 8 independent predictors of pre-treatment motor deficit and 7 independent predictors of 90-day mortality among patients with spinal epidural abscess is so important. The findings appear in the June 20, 2018 issue of JBJS.
The authors retrospectively analyzed data from 1,053 patients admitted with spinal epidural abscess at 2 tertiary medical centers and 3 regional community hospitals. Using multivariable logistic regression, they identified the following 8 significant risk factors for pre-treatment motor deficits in these patients:
- Sensory changes
- Urinary incontinence/retention
- Fecal incontinence/retention
- Abscess location proximal to conus medullaris
- Abscess location dorsal to the thecal sac
- Abscess in multiple locations
- White blood cell (WBC) count >12 X 109 cells/L
Similarly, the authors identified the following 7 significant risk factors for 90-day mortality:
- Age >65 years
- Active malignancy
- Renal disease requiring hemodialysis
- Pre-treatment motor deficit
- WBC count >15 X 109 cells/L
By themselves, these predictors are not prognostic, but the authors provide an algorithm that clinicians can use to generate an individualized probability of pre-treatment motor deficit or 90-day mortality for a given patient. The authors express hope that the resulting quantitative information will help guide management decisions for patients with spinal epidural abscess.
This tip comes from Fred Nelson, MD, an orthopaedic surgeon in the Department of Orthopedics at Henry Ford Hospital and a clinical associate professor at Wayne State Medical School. Some of Dr. Nelson’s tips go out weekly to more than 3,000 members of the Orthopaedic Research Society (ORS), and all are distributed to more than 30 orthopaedic residency programs. Those not sent to the ORS are periodically reposted in OrthoBuzz with the permission of Dr. Nelson.
It is well-established that total hip arthroplasty (THA) improves quality of life, but how about longevity itself? Cnudde et al.1 attempted to identify associations between THA and lower mortality rates, acknowledging that such rates may also be influenced by diagnostic, patient-related, socioeconomic, and surgical factors.
Using data from the Swedish Hip Arthroplasty Register, the authors identified 131,808 patients who underwent THA between January 1, 1999 and December 31, 2012. Among those patients, 21,755 died by the end of follow-up. Relative survival among the THA patients was compared with age- and sex-matched survival data from the entire Swedish population.
Patients undergoing elective THA had a slightly improved survival rate compared with the general population for approximately 10 years after surgery, but by 12 years, there was no survival-rate difference between patients undergoing THA and the general population (r = 1.01; 95% CI, 0.99-1.02; p = 0.13).
After controlling for other relevant factors and using primary osteoarthritis as the reference diagnosis, the authors found that patients undergoing THA for osteonecrosis of the femoral head, inflammatory arthritis, and secondary osteoarthritis had poorer relative survival.
In addition, married patients and those with higher levels of education fared better. The authors could not pinpoint the reasons for the increase in relative survival among THA patients, but these findings suggest that the explanation is most likely multifactorial.
- Do Patients Live Longer After THA and Is the Relative Survival Diagnosis-specific?Cnudde P, Rolfson O, Timperley AJ, Garland A, Kärrholm J, Garellick G, Nemes S. Clin Orthop Relat Res. 2018 Feb 28. doi: 10.1007/s11999.0000000000000097. [Epub ahead of print]
People 100 years old and older—centenarians—make up only 0.02% of the current US population. Nevertheless, the number of centenarians is expected to increase five-fold by 2060. That is in part what prompted Manoli III et al. to analyze a large New York State database to determine whether patients ≥100 years old who sustained a hip fracture fared worse in the hospital than younger hip-fracture patients. The study appears in the July 5, 2017 issue of The Journal of Bone & Joint Surgery.
Only 0.7% of the more than 168,000 patients ≥65 years old included in the analysis sustained a hip fracture when they were ≥100 years old. Somewhat surprisingly, centenarians incurred costs and had lengths of stay that were similar to those of the younger patients. However, despite those similarities, centenarians had a significantly higher in-hospital mortality rate than the younger patients. Male sex and an increasing number of comorbidities were found to predict in-hospital mortality for centenarians with hip fractures.
Manoli III et al. also found that, relative to other age groups, centenarians were managed nonoperatively at a slightly higher frequency when treated for extracapsular hip fractures. For intracapsular fractures, an increasing proportion of patients >80 years were managed with hemiarthroplasty and nonoperative treatment. Finally, among centenarians, time to surgery did not affect short-term mortality rates, suggesting a potential benefit to preoperative optimization.
In the February 1, 2017 edition of The Journal, Deren et al. provide an important analysis of muscle mass as it relates to mortality in older patients with an acetabular fracture. Among 99 fracture patients studied retrospectively, 42% had sarcopenia, defined in this study as a skeletal muscle index at the L3 vertebral body of <55.4 cm2/m2 for men and <38.5 cm2/m2 for women.
Deren et al. found that low BMI was associated with sarcopenia and that patients with sarcopenia were significantly more likely than patients without sarcopenia to sustain their skeletal injury from a low-energy mechanism. Sarcopenia was also associated with a higher risk of 1-year mortality, especially when in-hospital deaths were excluded. While the authors note that there’s no consensus definition for clinically diagnosing sarcopenia, they conclude that “sarcopenia based on the skeletal muscle index may be a better predictor of mortality than other commonly used classification
There are important subtextual messages in this study for all physicians who manage geriatric patients. Maintenance of muscle mass by resistance exercise (lifting weights, isometrics, etc.) is of critical importance in limiting fall risk and maintaining good balance and bone density. Dietary considerations are intertwined with exercise in maintaining muscle mass among older patients. Resistance training and cardio exercise help to maintain appetite, and adequate protein intake is of utmost importance. When families and medical teams work together, the risk of sarcopenia can be minimized, resulting in lower rates of falls, fewer low-energy fractures, and less mortality.
Marc Swiontkowski, MD