New Level-I Data on TKA Blood Conservation
Minimizing perioperative blood loss during total knee arthroplasty (TKA) helps curtail the risks and costs of allogeneic blood transfusions. Currently, the most popular pharmacological approach to blood conservation is the antifibrinolytic agent tranexamic acid (TXA). But in a randomized trial published in the October 4, 2017 edition of The Journal of Bone & Joint Surgery, Boese et al. found that a similar and much less expensive compound, epsilon-aminocaproic acid (EACA), performed almost as effectively and just as safely as TXA in patients undergoing unilateral knee replacement.
Although the 98 patients in the study who received TXA averaged less estimated blood loss than the 96 patients who received EACA, no transfusions were required in either group, and there were no statistically significant or clinically relevant between-group differences in the change in hemoglobin levels. On the safety/complication side, there were no statistically significant between-group differences in any measured parameter, including postoperative serum creatinine levels or renal, bleeding, or thrombotic complications. However, there were 3 pulmonary emboli in the EACA group compared with only 1 in the TXA group. While that was not a statistically significant difference, “an observed difference of this magnitude could limit the usefulness of EACA in TKA,” the authors caution.
This study did not compare the current cost of the two compounds, but back in 2012, when the authors’ institution added antifibrinolytics to their blood management program, TXA cost $43/g, compared with $0.20/g for EACA. The cost differential is striking, even when you consider that TXA is at least 7 times more potent than EACA on a molar basis, so less of the former drug is required.
Boese et al. conclude that “TXA does not have superior blood conservation effects or safety profile compared with EACA in TKA,” but they cite a need for future equivalence, superiority, and noninferiority trials with these drugs.
For TKA Pain Relief, Motor-Sparing Blocks Last Longer than Periarticular Infiltration
Analgesia after total knee arthroplasty (TKA) is a multimodal affair these days. Main goals include maintaining adequate patient comfort while limiting opiate use and permitting early mobilization.
In the August 2, 2017 issue of JBJS, Sogbein et al. report on a blinded randomized study comparing the performance of two types of analgesia often used in multimodal TKA pain-management protocols: preoperative motor-sparing knee blocks and intraoperative periarticular infiltrations.
Prior to surgery, the 35 patients in the motor-sparing block group received a midthigh adductor canal block under ultrasound guidance, combined with posterior pericapsular and lateral femoral cutaneous injections. The 35 patients in the periarticular infiltration group received study-labeled local anesthetics intraoperatively, just prior to component implantation.
Defining the “end of analgesia” as the point at which patient-reported pain at rest or activity rated ≥6 on the numerical rating scale and rescue analgesia was administered, the authors found that the duration of analgesia was significantly longer for the motor-sparing-block group compared with the periarticular-infiltration group. The infiltration group had significantly higher scores for pain at rest for the first 2 postoperative hours and for pain with knee movement at 2 and 4 hours. There were no between-group differences in time to mobilization, length of hospital stay, opiate consumption, or functional recovery.
Remove or Retain the PCL in TKA?
In the world of total knee arthroplasty (TKA), the arguments about retaining the posterior cruciate ligament (PCL) versus stabilizing the knee with posterior-stabilized components have raged for more than 30 years. The number of cohort studies and controlled trials attempting to clarify the issue have been too high to count. In the July 5, 2017 issue of The Journal, Vertullo et al. use the power of the Australian national joint registry to add additional important clinical information to the debate.
More than 62,000 TKA cases formed the substrate of this analysis. In a study-design twist, the revision-related outcomes were analyzed on the basis of the preference surgeons had for the two different design options, not on the basis of which prostheses were actually used. Consequently, there was a likelihood that the cohort of patients treated by surgeons who had a preference for posterior-stabilized designs would include some PCL-retained cases, and vice-versa. The authors claim that this “instrumental variable analysis” has “the capacity to remove the confounding by indication or disease severity against posterior-stabilized total knee replacements.” However, as with any registry study, there were still many confounding variables that could have influenced the revision rate, not the least of which is surgeon skill in component alignment and ligament tensioning.
Nevertheless, with selection bias minimized, Vertullo et al. found a real difference in revision rates favoring retention of the PCL. That finding does make biomechanical sense to this non-arthroplasty surgeon, who would expect less stress on the tibial component-bone interface at the extremes of knee motion with the PCL-retaining procedure.
Biomechanics notwithstanding, I think this very large registry-based arthroplasty study will influence the debate going forward, but I doubt it will end the debate or that it will change the TKA practices of many surgeons worldwide. For a more definitive and potentially practice-changing resolution to this clinical conundrum, we’ll need a very large (2,000 to 3,000 patients in each arm) international trial where surgeons and patients accept randomization between these two choices.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
The Opioid Epidemic: Consequences Beyond Addiction
The orthopaedic community worldwide—and especially those of us in the US, the nation most notorious for over-prescribing—has become very cognizant of the epidemic of opioid abuse. Ironically, the current problem was fueled partly by the “fifth vital sign” movement of 10 to 20 years ago, when physicians were encouraged (brow-beaten, in my opinion) to increase the use of opioid medications to “prevent” high pain scores.
Researchers internationally are now pursuing clarification on the appropriate use of these medications. The societal consequences of opioid addiction, which all too often starts with a musculoskeletal injury and/or orthopaedic procedure, have been well documented in the social-science and lay literature. In the May 17, 2017 issue of The Journal, Smith et al. detail an additional consequence to the chronic use of opioid drugs—the negative impact of preoperative opioids on pain outcomes following knee replacement surgery.
Approximately one-quarter of the 156 total knee arthroplasty (TKA) patients analyzed had had at least one preoperative opioid prescription. Patients who used opioids prior to TKA obtained less pain relief from the operation than those who had not used pre-TKA opioids. The authors also found that pain catastrophizing was the only factor measured that was independently associated with pre-TKA opioid use.
To be sure, we need to disseminate this information to the primary care community so they will be more judicious about prescribing these medications for knee arthritis. Additionally, knee surgeons should consider working with primary care providers to wean their TKA-eligible patients off these medications, with the understanding that chronic use preoperatively compromises postsurgical pain relief and functional outcomes.
We have previously published in The Journal the fact that the use of opioids is largely a cultural expectation that varies by country; physicians outside the US often achieve excellent postoperative pain management success without the use of these medications. My bottom line: We must continue to press forward to limit the use of opioid medications in both pre- and postoperative settings.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
Total Joint Arthroplasty: Does One Lead to Another?
An estimated 7 million people living in the US have undergone a total joint arthroplasty (TJA), and the demand for total hip arthroplasty (THA) and total knee arthroplasty (TKA) will almost certainly increase during the next 15 years. But how many people can expect to have an additional TJA after having a first one?
That’s the question Sanders et al. address in their historical cohort study, published in the March 1, 2017 edition of The Journal of Bone & Joint Surgery. They followed more than 4,000 patients who underwent either THA or TKA between 1969 and 2008 to assess the likelihood of those patients undergoing a subsequent, non-revision TJA.
Here’s what they found:
- Twenty years after an initial THA, the likelihood of a contralateral hip replacement was 29%.
- Ten years after an initial THA, the likelihood of a contralateral knee replacement was 6%, and the likelihood of an ipsilateral knee replacement was 2% at 20 years.
- Twenty years after an initial TKA, the likelihood of a contralateral knee replacement was 45%.
- After an initial TKA, the likelihood of a contralateral hip replacement was 3% at 20 years, and the likelihood of an ipsilateral hip replacement was 2% at 20 years.
In those undergoing an initial THA, younger age was a significant predictor of contralateral hip replacement, and in those undergoing an initial TKA, older age was a predictor of ipsilateral or contralateral hip replacement.
The authors conclude that “patients undergoing [THA] or [TKA] can be informed of a 30% to 45% chance of a surgical procedure in a contralateral cognate joint and about a 5% chance of a surgical procedure in noncognate joints within 20 years of initial arthroplasty.” They caution, however, that these findings may not be generalizable to populations with more racial or socioeconomic diversity than the predominantly Caucasian population they studied.
New Knee Content from JBJS
The recently launched JBJS Knee Spotlight offers highly relevant and potentially practice-changing knee content from the most trusted source of orthopaedic information.
Here are the five JBJS articles to which you will have full-text access through the Knee Spotlight during the month of March 2017:
- Improved Accuracy of Component Positioning with Robotic-Assisted Unicompartmental Knee Arthroplasty: Data from a Prospective, Randomized Controlled Study
- The Effect of Timing of Manipulation Under Anesthesia to Improve Range of Motion and Functional Outcomes Following Total Knee Arthroplasty
- Anatomic Single-Bundle ACL Reconstruction Is Possible with Use of the Modified Transtibial Technique: A Comparison with the Anteromedial Transportal Technique
- Autologous Chondrocyte Implantation in the Knee: Mid-Term to Long-Term Results
- Outcomes of Unicompartmental Knee Arthroplasty After Aseptic Revision to Total Knee Arthroplasty: A Comparative Study of 768 TKAs and 578 UKAs Revised to TKAs from the Norwegian Arthroplasty Register (1994 to 2011)
Knee studies offered on the JBJS Knee Spotlight will be updated monthly, so check the site often.
What’s New in Adult Reconstructive Knee Surgery
Every month, JBJS publishes a Specialty Update—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 all OrthoBuzz Specialty Update summaries.
This month, Gwo-Chin Lee, MD, author of the January 18, 2017 Specialty Update on Adult Reconstructive Knee Surgery, selected the five most clinically compelling findings from among the more than 100 studies summarized in the Specialty Update.
Nonoperative Knee OA Treatment
—Weight loss is one popular nonoperative recommendation for treating symptoms of knee osteoarthritis (OA). An analysis of data from the Osteoarthritis Initiative found that delayed progression of cartilage degeneration, as revealed on MRI and clinical symptoms, positively correlated with BMI reductions >10% over 48 months.1
Total Knee Arthroplasty
—In total knee arthroplasty (TKA), the drive toward producing normal anatomy has led to explorations of alternative alignment paradigms. A prospective randomized study found that small deviations from the traditional mechanical axis (known as kinematic alignment) can be well tolerated and do not lead to decreased survivorship or poorer functional outcomes at short-term follow up.2
—Controversy exists about the optimal method to achieve stemmed implant fixation in revision TKA. A randomized controlled trial of TKA patients with mild to moderate tibial bone loss found no difference in tibial implant micromotion between cemented and hybrid press-fit stem designs, based on radiostereometric analysis.
Blood Management in TKA
—Minimizing blood loss and transfusions is crucial to minimizing complications after TKA. A randomized, double-blind, placebo-controlled trial found that intra-articular and intravenous administration of tranexamic acid (TXA) was more effective than intravenous TXA alone, without an increased risk of venous thromboembolism (VTE). However, the optimal regimen for TXA remains undefined.
VTE/PE Prophylaxis
—VTE prophylaxis is essential for all patients undergoing TKA. A risk-stratification study of pulmonary embolism (PE) after elective total joint arthroplasty reported that the incidence of PE within 30 days after either hip or knee replacement was 0.5%. Risk factors associated with PE were age of > 70 years, female sex, and higher BMI. The presence of anemia was protective against PE. The authors developed an easy-to-use scoring system to determine risk for VTE to help guide chemical prophylaxis.3
References
- Gersing AS, Solka M, Joseph GB, Schwaiger BJ, Heilmeier U, Feuerriegel G, Nevitt MC, McCulloch CE,Link TM. Progression of cartilage degeneration and clinical symptoms in obese and overweight individuals is dependent on the amount of weight loss: 48-month data from the Osteoarthritis Initiative. Osteoarthritis Cartilage. 2016 Jul;24(7):1126-34. Epub 2016 Jan 30.
- Calliess T, Bauer K, Stukenborg-Colsman C, Windhagen H, Budde S, Ettinger M. PSI kinematic versus non-PSI mechanical alignment in total knee arthroplasty: a prospective, randomized study. Knee Surg Sports Traumatol Arthrosc. 2016 Apr 27. [Epub ahead of print]
- Bohl DD, Maltenfort MG, Huang R, Parvizi J, Lieberman JR, Della Valle CJ. Development and validation of a risk stratification system for pulmonary embolism after elective primary total joint arthroplasty. J Arthroplasty. 2016 Sep;31(9)(Suppl):187-91. Epub 2016 Mar 17.
New Knee Content from JBJS
The recently launched JBJS Knee Spotlight offers highly relevant and potentially practice-changing knee content from the most trusted source of orthopaedic information.
Here are the five JBJS articles to which you will have full-text access through the Knee Spotlight during the month of February 2017:
-
Comparison of Highly Cross-Linked and Conventional Polyethylene in Posterior Cruciate-Substituting Total Knee Arthroplasty in the Same Patients
-
What’s New in Adult Reconstructive Knee Surgery
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Hinged External Fixation in the Treatment of Knee Dislocations: A Prospective Randomized Study
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A Randomized, Controlled, Prospective Study Evaluating the Effect of Patellar Eversion on Functional Outcomes in Primary Total Knee Arthroplasty
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Comparison of Functional Outcome Measures After ACL Reconstruction in Competitive Soccer Players: A Randomized Trial
Knee studies offered on the JBJS Knee Spotlight will be updated monthly, so check the site often.
Long-Term Opioid Use Before TKA Raises Risk of Revision
Given the prevalence of opioid prescriptions, many patients present for total knee arthroplasty (TKA) having been on long-term opioid therapy. In the January 4, 2017 edition of The Journal of Bone & Joint Surgery, Ben-Ari et al. determined that patients taking opiate medications for more than three months prior to their TKA were significantly more likely than non-users of opioids to undergo revision surgery within a year after the index procedure.
Among the more than 32,000 TKA patients from Veterans Affairs (VA) databases included in the study, nearly 40% were long-term opioid users prior to surgery. Despite that high percentage, the authors found that chronic kidney disease was the leading risk factor for knee revision among the relevant variables they examined. And even though the authors used a sophisticated natural language/machine-learning tool to analyze postoperative notes, they found no association between long-term opioid use and the etiology of the revisions.
In a commentary accompanying the study, Michael Reich, MD and Richard Walker, MD, note that the study’s very specific VA demographic (94% male) may hamper the generalizability of the findings, especially because most TKAs are currently performed in women. Nevertheless, the commentators conclude that:
- “The study illuminates the value in limiting opioid use during the nonoperative treatment of patients with knee arthritis.”
- “Patients who are taking opioids when they present for TKA could reasonably be encouraged to decrease opioid use during preoperative preparation.”
- “Preoperative use of opioids should be considered among modifiable risk factors and comorbidities when deciding whether to perform TKA.”
Guest Post: New AUC for Surgical Management of Knee OA
OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Richard Yoon, MD and Grigory Gershkovich, MD.
The AAOS recently reviewed the evidence for surgical management of osteoarthritis of the knee (SMOAK) and issued a set of appropriate use criteria (AUC) that help determine the appropriateness of clinical practice guidelines (CPGs). These AUC can be accessed on the OrthoGuidelines website: www.orthoguidelines.org/auc.
The AUC were developed after a panel of specialists reviewed the 2015 CPGs on SMOAK and made appropriateness assessments for a multitude of clinical scenarios and treatments. The panel found 21% of the voted-on items “appropriate”; 25% were designated “maybe appropriate,” and 54% were ranked as “rarely appropriate.”
Importantly, these AUC do not provide a substitute for surgical decision making. The physician should always determine treatment on an individual basis, ideally with the patient fully engaged in the decision.
This OrthoBuzz post summarizes some of the updated conclusions according to three clinical time points—pre-operative, peri-operative, and postoperative—specifying the strength of supporting evidence. This post is not intended to review appropriateness for every clinical scenario. We encourage physicians to explore the OrthoGuidelines website for complete AUC information.
Pre-operative
Strong evidence: Obese patients exhibit minimal improvement after total knee arthroplasty
(TKA), and such patients should be counseled accordingly.
Moderate evidence: Diabetic patients have a higher risk of complications after TKA.
Moderate evidence: An 8-month delay to TKA does not worsen outcomes.
Peri-operative
Strong evidence: Both peri-articular local anesthetics and peripheral nerve blocks decrease postoperative pain and opioid requirements.
Moderate evidence: Neuraxial anesthesia may decrease complication rates and improve select peri-operative outcomes.
Moderate evidence: Judicious use of tourniquets decreases blood loss, but tourniquets may also increase short-term post-operative pain.
Strong evidence: The use of tranexamic acid (TXA) reduces post-operative blood loss and the need for transfusions.
Strong evidence: Drains do not help reduce complications or improve outcomes.
Strong evidence: There is no difference in outcomes between cruciate-retaining and posterior stabilized implants.
Strong evidence: All-polyethylene and modular components yield similar outcomes.
Strong, moderate, and limited evidence to support either cemented or cementless techniques, as similar outcomes and complication rates were found.
Strong evidence: There is no difference in pain/function with patellar resurfacing.
Moderate evidence: Patellar resurfacing decreases 5-year re-operation rates.
Moderate evidence shows no difference between unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO).
Moderate evidence favors TKA over UKA to avoid future revisions.
Strong evidence against the use of intraoperative navigation and patient-specific instrumentation, as no difference in outcomes has been observed.
Postoperative
Strong evidence: Rehab/PT started on day of surgery reduces length of stay.
Moderate evidence: Rehab/PT started on day of surgery reduces pain and improves function.
Strong evidence: The use of continuous passive motion machines does not improve outcomes after TKA.
Richard Yoon, MD is a fellow in orthopaedic traumatology and complex adult reconstruction at Orlando Regional Medical Center.
Grigory Gershkovich, MD is chief resident at Albert Einstein Medical Center in Philadelphia. He will be completing a hand fellowship at the University of Chicago in 2017-2018.
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