Physical Parameters Beyond BMI Affect TKA Outcomes
It is well established that obese patients who undergo total joint arthroplasty have increased risks of complications and infections. But what about folks who are not obese, but are just generally large? Do they also have increased post-arthroplasty complications, compared to their smaller counterparts? That is the question Christensen et al. explored in a registry-based study in the November 7, 2018 edition of JBJS.
In addition to BMI, the authors examined 3 other physical parameters—body surface area, body mass, and height—to determine whether these less-studied characteristics (all contributing to “bigness”) were associated with an increased rate of various adverse outcomes, including mechanical failure and infection, after primary total knee arthroplasty (TKA). They evaluated data from more than 22,000 TKAs performed at a single institution and found that the risk of any revision procedure or revision for a mechanical failure was directly associated with every 1 standard deviation increase in BMI (Hazard Ratio [HR], 1.19 and 1.15, respectively), body surface area (HR, 1.37 and 1.35, respectively), body mass (HR, 1.30 and 1.27, respectively), and height (HR, 1.22 and 1.23, respectively). In this study, 1 standard deviation was equivalent to 6.3 kg/m2 for BMI, 0.3 m2 for body surface area, 20 kg for body mass, and 10.5 cm for height.
These findings, while not all that surprising, are enlightening nonetheless. The study shows that increasing height has a greater negative impact on TKA outcomes than previously thought. While I spend a lot of time counseling patients with high BMIs about the increased risks of undergoing a TKA (and while such patients can take certain actions to lower their BMI prior to surgery), I do not spend nearly as much time counseling patients who are much taller than normal about their increased risks (and height is not a modifiable risk factor). Nor do I spend much time thinking about a patient’s overall body mass or body surface area in addition to their BMI. This study will remind me not to overlook these less commonly examined physical parameters when discussing TKA with patients in the future.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
Multisite Evaluation of a Custom Energy-Storing Carbon Fiber Orthosis for Patients with Residual Disability After Lower-Limb Trauma
Opioid Consumption After Knee Arthroscopy
Better News for TJA Patients with Depression
Over the last 2 decades, research into how various “preexisting conditions” affect the outcomes of orthopaedic interventions has increasingly focused on the impact of mental health (a patient’s “state of mind” and coping abilities) and psychological diagnoses such as depression. The impact of mental health, depression, and personality characteristics on patient-reported outcomes following significant skeletal trauma has been well documented in the trauma literature. In addition, previous studies in knee arthroplasty have identified depression as a major factor in suboptimal patient outcomes.
In the October 17, 2018 issue of The Journal, Halawi et al. teased out the impact of depression and mental health—independently and in combination—on patient-reported outcomes following primary total joint arthroplasty (TJA) in 469 patients at a minimum follow-up of one year.
The authors used the validated SF-12 MCS instrument to assess patient baseline mental health at the time of surgery. They also used the widely accepted WOMAC score to assess joint-specific pain, stiffness, and physical function before and after surgery. Using these tools, the authors showed that, while depression alone may diminish some patient-reported gains obtained from arthroplasty, it does not seem to affect a patient’s overall outcome as much as poor mental health prior to surgery. In this study, patients with depression but good mental health achieved patient-reported outcomes comparable to those among normal controls. Still, patients without depression and in good mental health were found to have the most robust improvements after undergoing TJA.
Orthopaedic surgeons need to better understand the interplay between these complex psychological states and patient outcomes. These authors conclude that the effect of depression on patient-reported outcomes is “less pessimistic than previously thought,” but we welcome further studies examining the link between “the mind” and orthopaedic outcomes. Finally, we should be ready to refer patients to our mental health colleagues when we detect a potential underlying nonphysical condition that might adversely affect the magnitude of benefit from the treatments we offer.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
Cost Analysis of Treatments for Unicompartmental Knee Arthritis: UKA Wins
Surgical treatment for knee osteoarthritis (OA) has become increasingly common. The many people who have damage to only one part of their joint (unicompartmental knee OA) are faced with three options—total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA), or nonsurgical treatment. A study by Kazarian et al. in the October 3, 2018 issue of The Journal estimates the lifetime cost-effectiveness for those three options in patients from 40 to 90 years of age.
The authors used sophisticated computer modeling to estimate both direct costs (those related to medical/surgical care) and indirect costs (such as missed workdays) of the three options as a function of patient age at the time of treatment initiation. Here are the key findings:
- The surgical treatments were less expensive and provided patients from 40 to 69 years of age with a greater number of quality-adjusted life years (QALYs) than nonsurgical treatment.
- In patients 70 to 90 years of age, surgical treatments were still cost-effective compared with nonsurgical treatment, albeit less so than in younger patients. In this older age group, “cost-effectiveness ratios” of surgical treatment remained below a “willingness to-pay” threshold of $50,000 per QALY.
- When the two surgical treatments were compared to one another, UKA beat TKA decisively in cost-effectiveness among patients of any age.
After crunching more numbers, Kazarian et al. estimated that, by 2020, if all of the patients with unicompartmental knee OA who were candidates for UKA or TKA (a projected total of 120,000 to 210,000 people) received UKA, “it would lead to a lifetime cost savings of $987 million to $1.5 billion.
From these findings, the authors conclude that patients with unicompartmental knee OA should receive surgical treatment, preferably UKA, instead of nonsurgical treatment until the age of 70 years. After that age, all three options are reasonable from a cost-effectiveness perspective.
But perhaps the most important thing to remember about these findings is that they add information to—but should not replace—clinical decision-making based on complete and open communication between doctor and patient.
JBJS 100: Approach to the Lumbar Spine, Knee Flexion Contracture
Under one name or another, The Journal of Bone & Joint Surgery has published quality orthopaedic content spanning three centuries. In 1919, our publication was called the Journal of Orthopaedic Surgery, and the first volume of that journal was Volume 1 of what we know today as JBJS.
Thus, the 24 issues we turn out in 2018 will constitute our 100th volume. To help celebrate this milestone, throughout the year we will be spotlighting 100 of the most influential JBJS articles on OrthoBuzz, making the original full-text content openly accessible for a limited time.
Unlike the scientific rigor of Journal content, the selection of this list was not entirely scientific. About half we picked from “JBJS Classics,” which were chosen previously by current and past JBJS Editors-in-Chief and Deputy Editors. We also selected JBJS articles that have been cited more than 1,000 times in other publications, according to Google Scholar search results. Finally, we considered “activity” on the Web of Science and The Journal’s websites.
We hope you enjoy and benefit from reading these groundbreaking articles from JBJS, as we mark our 100th volume. Here are two more:
The Paraspinal Sacrospinalis-Splitting Approach to the Lumbar Spine
LL Wiltse, JG Bateman, RH Hutchinson, WE Nelson: JBJS, 1968 July; 50 (5): 919
In this classic 1968 JBJS paper, Wiltse and co-authors described a novel and innovative access route to the lumbar spine. Advantages included reduced blood loss, less muscle ischemia, and the preservation of spinous processes and intra-/supraspinous ligaments. The Wiltse approach still represents one of the main access routes to the lumbar spine.
Treatment of Knee Flexion Contracture Due to Central Nervous System Disorders in Adults
JN Martin, R Vialle, P Denormandie, G Sorriaux, H Gad, I Harding, O Dizien, T Judet: JBJS, 2006 April; 88 (4): 840
To address what was at the time a lack of interest among orthopaedic surgeons in treating spasticity in adults, these authors expanded upon earlier work studying the treatment of knee flexion contractures in this population. Their procedure included distal hamstring lengthening, a posterior capsulotomy in some of the knees, and use of a unilateral external fixator in most of the knees. Mean flexion contracture improved from a mean of 69° preoperatively to a mean of 6.2° at 1 to 5 years after surgery.
Influence of Physical Activity Level on Total Knee Arthroplasty Expectations, Satisfaction, and Outcomes
Background: Patients undergoing total knee arthroplasty expect pain relief, functional improvement, and a return to physical activity. The objective of this study was to determine the impact of patients’ baseline physical activity level on preoperative expectations, postoperative satisfaction, and clinical outcomes in patients undergoing total knee arthroplasty.
Location, Location, Location: Geographic Disparities in Orthopaedic Care?
When it comes to access to many things people look for, big cities offer numerous advantages over small towns. This seems to be true for consumer goods and services—and for access to health care, especially “high-tech” procedures. That is one issue that Suchman et al. touch on in their retrospective database study in the September 19, 2018 issue of The Journal.
The study evaluated almost 650,000 patients who underwent one of three meniscal procedures (meniscectomy, meniscal repair, or meniscal allograft transplantation) in New York State from 2003 to 2015. In determining which procedures were performed where, the authors found that meniscectomies and meniscal repairs—the vast majority of the procedures performed—were scattered throughout the state, but that meniscal transplants were performed almost exclusively at urban, academic hospitals. This finding is not surprising, considering the technical complexity of allograft transplantation. However, if a patient who would benefit from a meniscal allograft lived three hours from an urban, academic setting, they would either have to travel to the city to be evaluated, treated, and followed, or settle for a different procedure from a surgeon closer to home. Neither option would be optimal in terms of quality care.
At the same time, this article emphasizes that not every patient needs to go to a large hospital to receive excellent care. While a preponderance of recent data shows an association between hospital and surgeon procedure volume and patient outcomes, those data do not mean that smaller hospitals or “medium volume” surgeons should not perform certain procedures. In fact, medium volume surgeons performed the largest proportion of meniscal procedures evaluated in this study.
The fact is that the “delivery” of health care does not happen via FedEx or UPS. The burden falls on patients to transport themselves to the physician, not vice versa. And until that model drastically changes, access disparities based on geography will likely remain.
However, Suchman et al. also found that the majority of patients who underwent any meniscal procedure had private insurance—and that Medicaid patients had the lowest rates of meniscal surgery. Although disparities arising from socioeconomic/insurance status are also very difficult to address, they would seem to be more remediable than disparities related to geography.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
Primary TJA Volume Growth from 2014 to 2030: Not So Fast?
Annual volume projections for total joint arthroplasty (TJA) have been cited frequently and applied broadly, often to estimate future costs. But with a slowdown in the growth of the annual incidence of total knee arthroplasty (TKA), updated projections are needed, and that’s what Sloan et al. provide in the September 5, 2018 issue of JBJS.
Using the National Inpatient Sample to obtain TJA incidence data, the authors first analyzed the volume of primary TJA procedures performed from 2000 to 2014. They then performed regression analyses to project future volumes of TJA procedures. Here are the numbers based on the 2000-to-2014 data:
- Primary total hip arthroplasty (THA) is projected to grow 71%, to 635,000 annual procedures by 2030.
- Primary TKA is projected to grow 85%, to 1.26 million annual procedures by 2030.
However, the TKA procedure growth rate has slowed in recent years, and models based on 2008-to-2014 data project growth to only 935,000 annual TKAs by 2030—325,000 fewer procedures relative to the 2000-to-2014 models.
Earlier studies, notably one by Kurtz et al. in 2007, obviously could not account for the reduced growth rate in TKA after 2008. A 2008 analysis by Wilson et al., based on the Kurtz et al. data, estimated that annual Medicare expenditures on TJA procedures would climb from $5 billion in 2006 to $50 billion in 2030. “Using our projections,” say Sloan et al., “we predict that Medicare expenditures on these procedures in 2030 will be less than half of that predicted by Wilson et al.”
These findings lend credence to the authors’ observation that “it is imperative that projections of orthopaedic procedures be regularly evaluated and updated to reflect current rates.”
German Knee OA Guidelines Mirror Findings in JBJS Reviews Article
OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Prof. Joerg Jerosch, in response to a recent article in JBJS Reviews.
I congratulate Vannabouathong et al. for the well-performed and relevant systematic review. In Germany, the Association of Scientific Medical Societies (AWMF) just published a guideline on the medical treatment of knee osteoarthritis (see: https://www.awmf.org/uploads/tx_szleitlinien/033-004l_S2k_Gonarthrose_2018-01_1.pdf), which comes to very similar conclusions as those presented in this systematic review.
The new German guideline suggests a four-stage algorithm starting with topical NSAIDs and escalating to oral NSAIDs (according to individual risks), then followed either by glucosamine, hyaluronic acid (HA), or corticosteroids, and ends finally with opioids. It was very useful that Vannabouathong et al. used the AAOS description for clinical significance, and it was elegant of them to include the effect of intra-articular placebo in their analysis of intra-articular treatments. This review compares treatment-group differences (not within-patient improvements) and considers that the placebo effect in osteoarthritis trials is typically large, particularly in the case of intra-articular injections. Consequently, the measured effect size would underestimate the clinical benefits for patients1, 2. It is valuable that this systematic review calculated the intra-articular placebo versus the oral placebo effect and added the resulting difference of 0.29 standard deviation (SD) units to the respective effect sizes of the intra-articular treatments.
This review concludes that the intra-articular injection of HA has the most concise effect estimate and exceeds the defined threshold of clinical importance of 0.5 SD units. Thus the clinical usefulness of HA is boosted from “possibly clinically important” to “clinically important” according to the AAOS definitions. This review also investigates HA formulations in terms of different molecular weights. It illustrates clearly the effect sizes of high-molecular-weight HA formulations between 1,500 kDa and 6,000 kDa, as well as those above 6,000 kDa.
One point requiring further discussion is that many patients have contraindications to NSAIDs due to comorbidities or comedications. Our new German guideline points out that NSAIDs are contraindicated for elderly patients (>60 years old) and those with existing ulcers, GI bleeding, or infections with H. pylori. Additional contraindicated factors are comedications such as corticosteroids, anticoagulants, or aspirin. In addition, the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) reasons that oral NSAIDs have a moderate effect on pain relief, but they are associated with a 3- to 5-fold increase in the risk of upper GI complications, including peptic ulcer perforation, obstruction, and bleeding3.
Another analysis from the Coxib and Traditional NSAID Trialists (CNT) Collaboration shows that 2 to 4 out of 1,000 patients face GI complications after the daily intake of 150 mg of diclofenac. The same applies for 6 to 16 out of 1,000 patients taking 1,000 mg of ibuprofen per day4. An announcement of the Medicines Commission of the German Medical Profession also mentions high relative risks for GI complications associated with NSAIDs. The German guideline recommends intra-articular HA injections especially for individuals at risk for adverse NSAID side effects and for those for whom NSAIDs are not sufficiently effective.
The German guideline also discusses potentially beneficial effects of combining corticosteroids with HA. This should be a topic for a future systematic review.
Prof Joerg Jerosch is a professor of orthopaedic surgery at Johanna-Etienne Hospital in Neuss, Germany.
References
1. Bannuru RR et al., Therapeutic trajectory following intra-articular hyaluronic acid injection in knee osteoarthritis e meta-analysis, Osteoarthritis Cartilage. 2011 Jun;19(6):611-9. doi: 10.1016/j.joca.2010.09.014.
2. Bannuru RR et al., Comparative effectiveness of pharmacologic interventions for knee osteoarthritis: a systematic review and network meta-analysis, Ann Intern Med. 2015 Jan 6;162(1):46-54. doi: 10.7326/M14-1231
3. Bruyere O et al. A consensus statement on the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) algorithm for the management of knee osteoarthritis-From evidence-based medicine to the real-life setting. Semin Arthritis Rheum, 2016. 45(4 Suppl): p. S3-11
4. Bhala N et al., Coxib and traditional NSAID Trialists’ (CNT) Collaboration, Vascular and upper gastrointestinal effects of non-steroidal anti-inflammatory drugs: meta-analyses of individual participant data from randomised trials. Lancet 2013; 382(9894): 769-779
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