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.
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.
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
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.
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 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
- 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.
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.
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.
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.
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.
Of the hundreds of thousands of total knee arthroplasties (TKAs) performed annually around the world, very few result in failure so irreparable that transfemoral amputation is the last resort. But what does “very few” really mean? In the December 7, 2016 issue of The Journal of Bone & Joint Surgery, Gottfriedsen et al. determine the cumulative incidence of amputation for failed TKAs among nearly 93,000 registered knee replacements performed in Denmark from 1997 to 2013.
The authors used a competing-risk model (which took into account the competing risk of death) to avoid overestimating incidence. From a total of 115 amputations performed for causes related to failed TKA, they calculated a cumulative 15-year incidence of amputation of 0.32%. They noted a tendency toward decreasing incidence during the 2008-2013 period, relative to the 1997-2002 period.
The three most common causes of post-TKA amputation were periprosthetic infection (83%), soft-tissue deficiency (23%), and severe bone loss (18%). The authors add, however, that the latter two causes are “most likely the result of long-term infection together with several revision procedures, in which soft tissue and bone stock are gradually damaged.”
The authors encourage orthopaedists to consider newer treatment options to avoid amputation (such as skin grafts and muscle flaps for soft-tissue loss), but they also assert that, in each individual case, those contemporary approaches should be balanced against the “psychological and physical strains related to repeated surgery performed in an attempt to salvage the knee.”
Hyaluronic Acid Injections for Treatment of Advanced Osteoarthritis of the Knee: Utilization and Cost in a National Population Sample
There is a rise in knee osteoarthritis, particularly in the aging U.S. population. A practice known as hyaluronic acid (HA) injections is used for the treatment of knee osteoarthritis; however, its efficacy and cost-effectiveness are being debated. In this study, the utilization and costs of HA injections were evaluated during the 12 months preceding total knee arthroplasty (TKA) and the usage of HA injections in end-stage knee osteoarthitis management in relation to other treatments was also evaluated. Truven Health Analytics databases (MarketScan Commercial Claims and Encounters and Medicare Supplemental and Cooridination of Benefits) were reviewed in order to find patients who underwent TKA from 2005 to 2012. All patient-specific osteoarthritis-related health care, including medications, corticosteroid injections, HA injections, imaging, and office visits, as well as payment information were analyzed during the 12 months before TKA.
244,059 patients met the inclusion criteria, and 35,935 (14.7%) of them had > 1 HA injections in the 12-month period. HA accounted for 16.4% of all payments related to osteoarthritis, coming in second only to imaging studies (18.2%). In terms of treatment-specific payments, HA injections accounted for 25.2%, a rate higher than that of any other treatment. Compared with patients who did not receive HA injections, patients who had the injections were significantly more likely to receive additional knee osteoarthritis-related treatment.
HA injections are still frequently used to treat osteoarthritis of the knee even though there have been numerous studies that question their efficacy and cost-effectiveness for that purpose. Based on the results and a lack of data supporting the effectiveness of HA injections in the current cost-conscious health-care climate, the authors of this study concluded that decreasing the use of HA injections for patients with end-stage knee osteoarthritis may substantially reduce cost without adversely affecting the quality of care.
When Verburg et al. designed their randomized clinical trial, published in the June 15, 2016 edition of The Journal of Bone & Joint Surgery, they hypothesized that a mini-midvastus (MMV) approach to total knee arthroplasty (TKA) would yield better outcomes than a conventional approach. However, during short- and mid-term follow-up (up to 5 years postoperatively) on 84 TKAs (42 in each group), the researchers found no relevant clinical or radiographic differences between the two groups, both of which received the same brand of posterior-stabilized implant.
On average, the MMV procedure took 6 minutes longer, and those in the MMV group had better range of motion on postoperative day 3. On the downside, more wound-healing problems such as blisters were observed in the MMV group, especially in large male patients, which the authors attribute to soft-tissue interactions caused by the use of necessarily large components with small incision lengths.
Verburg et al. concluded that “the advantage of the MMV approach was merely a smaller scar,” and they do not recommend MMV or other minimally invasive/quadriceps-sparing approaches for “larger patients or muscular men.”
Many surgeons recommend primary unilateral knee arthroplasty (UKA) over primary total knee arthroplasty (TKA) or tibial osteotomy for younger patients with unicompartmental knee osteoarthritis. Some do so believing that the results of any subsequent revision to TKA (UKA → TKA) will be better than a revision of a primary TKA to a second TKA (TKA → TKA).
A comparative, registry-based study by Leta et al. in the March 16, 2016 JBJS found that both revision categories yielded essentially the same outcomes. The authors found no significant differences between the two strategies in terms of overall implant survival rate or risk of re-revision, or in several patient-reported outcomes: the EuroQol EQ-5D, KOOS, and VAS pain and satisfaction scores. Two notable exceptions were as follows:
- The risk of re-revision was twice as high for TKA → TKA patients who were older than 70 years of age
- UKA → TKAs were more often re-revised because of a loose tibial component and pain alone, while TKA → TKAs were more often re-revised because of deep infection.
With few significant outcome differences, commentator Geoffrey Dervin, MD suggests that “patients facing the initial decision between UKA and TKA should focus more on differences in perioperative morbidity, clinical outcomes, and satisfaction” from the primary procedure rather than on the outcomes of revision should it be required.