OrthoBuzz occasionally receives posts from guest bloggers. In response to a recent study in The New England Journal of Medicine, the following commentary comes from Paul E. Matuszewski, MD.
A recent issue of The New England Journal of Medicine published the results from a large, multicenter randomized trial comparing the outcomes of hemiarthroplasty versus total hip arthroplasty (THA) to treat displaced femoral neck fractures in ambulatory adults.
The HEALTH investigators enrolled 1,495 patients in the study, and 85.1% of those patients had complete data for analysis after 2 years. The researchers found no significant differences between the groups with regard to the primary outcome—secondary hip procedures (7.9% in the THA group vs 8.3% in the hemi group). The risk of secondary hip procedures during the first year was higher in the THA group, but the hemiarthroplasty group had a higher risk of secondary procedures in the second year. Open/closed reductions of hip dislocations were the most common secondary procedures among the THA group, and revision to THA was the most common secondary procedure in the hemiarthroplasty group. The THA group had slightly better WOMAC scores, but the difference was not within a clinically significant range. There were no between-group differences noted in other patient-reported outcomes.
The HEALTH investigators followed these patients for only two years, which is notably the standard for many orthopaedic studies, but this short follow-up limits the practical application of these findings. The authors note that after the first year, primary THA was favorable with regard to secondary hip procedures. It is reasonable to think that this difference may become more compelling beyond 2 years, as more patients who received hemiarthroplasty are likely to be converted to THA.
The suggestion that there may not be an early benefit of THA over hemiarthroplasty in the ambulatory adult with a displaced femoral neck fracture contrasts with current recommendations from the American Academy of Orthopaedic Surgeons. However, the 2-year follow-up of this trial represents only a “snapshot” of the continuum of outcomes from these two hip-fracture treatments. The findings may add to our understanding of what our patients can expect during the first 2 years following these procedures, but I would caution surgeons against making any drastic changes to their current practice in response to this data.
Paul E. Matuszewski, MD is the Director of Orthopaedic Trauma Research and Assistant Professor of Orthopaedic Traumatology at the University of Kentucky.
Manufacturing, farming, and shopping…These are just 3 diverse examples of how technology is advancing daily and automating tedious tasks, decreasing costs, and improving efficiencies. Orthopaedics and orthopaedic research are not being left behind in this progression. In the November 6, 2019 edition of JBJS, Wyles et al. evaluate the accuracy of natural language processing (NLP) tools in automating the extraction of orthopaedic data from electronic health records (EHRs) and registries. The findings suggest that NLP-generated algorithms can indeed reliably extract data without the labor-intensive and costly process of manual chart reviews.
First, using an open-source NLP “engine,” the researchers developed NLP algorithms focused on 3 elements of >1,500 total hip arthroplasty (THA) procedures captured in the Mayo Total Joint Registry: (1) operative approach, (2) fixation technique, and (3) bearing surface. They then applied the algorithm to operative notes from THAs performed at Mayo and to THA-specific EHR data from outside facilities to determine external validity.
Relative to the current “gold-standard” of manual chart reviews, the algorithm had an accuracy of 99.2% in identifying the operative approach, 90.7% in identifying the fixation technique, and 95.8% in identifying the bearing surface. The researchers found similar accuracy rates when they applied the algorithm to external operative notes.
The findings from this study strongly suggest that properly “trained” NLP algorithms may someday eliminate the need for manual data extraction. That, in turn, could substantially streamline future research, policy, and surveillance tasks within orthopaedics. As Gwo-Chin Lee, MD predicts in his Commentary on this study, “When perfected, NLP will become the gold standard in the initial data mining of patient records for research, billing, and quality-improvement initiatives.” Dr. Lee is quick to add, however, that “no machine learning can occur…without the integral and indispensable input of the human element.”
Orthopaedic surgeons are already using robots to assist them in performing total joint arthroplasties. Wyles et al. show how we can use technology to reliably expedite research on that same subject. I believe the future holds much promise for the use of ever-advancing technologies in orthopaedic surgery and research.
Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media
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 all OrthoBuzz Specialty Update summaries. This month, Mengnai Li, MD, co-author of the September 18, 2019 “What’s New in Hip Replacement,” selected the five most clinically compelling findings from among the more than 100 studies summarized in the article.
–Pathology involving the spinopelvic relationship has dominated the recent literature on THA dislocation. For patients presenting with a flatback deformity and stiff spine, who had the highest risk of dislocation, the authors of a recent study suggested the use of a dual-mobility implant construct with targeted 30° of anteversion relative to the functional pelvic plane, based on a standing anteroposterior radiograph.1
Preferred Implant Designs
–A study comparing data from the American Joint Replacement Registry with national registry data from other countries found that cementless stem fixation with the use of ceramic and 36-mm heads was the current US preference, while non-US registries indicated that cemented implants and metal and 32-mm heads were used most commonly.2
–The ongoing effort in the orthopaedic community to reduce opioid consumption without compromising quality of life for joint-replacement patients may be aided by findings from a recent randomized controlled trial. The study found that prescribing 30 immediate-release oxycodone pills instead of 90 pills was associated with a significant reduction in unused pills and decreased opioid consumption without affecting pain scores and patient-reported outcomes.3
– A retrospective review of >4,900 patients who underwent THA or TKA found that 16.2% reported a history of penicillin allergy. No patients among those with a stated penicillin allergy who were given cefazolin had an adverse reaction. Also, there was no increased rate of surgical site infections among those with a stated penicillin allergy who received clindamycin or vancomycin, although the authors acknowledged that this part of the study was underpowered due to the low overall rate of infection.4
Use of TXA
–Recent guidelines on the use of tranexamic acid (TXA) state that no specific routes of administration, dosage, dosing regimen, or time of administration have been shown to provide clearly superior blood-sparing properties.5
- Luthringer TA, Vigdorchik JM. A preoperative workup of a “hip-spine” total hip arthroplasty patient: a simplified approach to a complex problem. J Arthroplasty.2019 Jan 18. [Epub ahead of print].
- Heckmann N, Ihn H, Stefl M, Etkin CD, Springer BD, Berry DJ, Lieberman JR. Early results from the American Joint Replacement Registry: a comparison with other national registries. J Arthroplasty.2019 Jan 5.
- Hannon CP, Calkins TE, Li J, Culvern C, Darrith B, Nam D, Gerlinger TL, Buvanendran A, Della Valle CJ. The James A. Rand Young Investigator’s Award: large opioid prescriptions are unnecessary after total joint arthroplasty: a randomized controlled trial. J Arthroplasty.2019 Feb 4. [Epub ahead of print].
- Stone AH, Kelmer G, MacDonald JH, Clance MR, King PJ. The impact of patient-reported penicillin allergy on risk for surgical site infection in total joint arthroplasty. J Am Acad Orthop Surg.2019 Feb 27. [Epub ahead of print].
- Fillingham YA, Ramkumar DB, Jevsevar DS, Yates AJ, Bini SA, Clarke HD, Schemitsch E, Johnson RL, Memtsoudis SG, Sayeed SA, Sah AP, Della Valle CJ. Tranexamic acid use in total joint arthroplasty: the clinical practice guidelines endorsed by the American Association of Hip and Knee Surgeons, American Society of Regional Anesthesia and Pain Medicine, American Academy of Orthopaedic Surgeons, Hip Society, and Knee Society. J Arthroplasty.2018 Oct;33(10):3065-9. Epub 2018 Aug 7.
Much has been written in recent years about the orthopaedist’s predilection for prescribing opioids, most of which has been aimed at helping us become better stewards of these medications. It is imperative that we continue learning how best to prescribe opioids to maximize their effectiveness in postoperative pain management, while minimizing their many harmful and potentially lethal effects. With some patients, finding that balance is much easier than with others. Learning to identify which patients may struggle with achieving that equilibrium is one way to address the current opioid epidemic.
In the September 18, 2019 issue of The Journal, Prentice et al. identify preoperative risk factors that are associated with prolonged opioid utilization after total hip arthroplasty (THA) by retrospectively evaluating the number of opioid prescriptions dispensed to >12,500 THA patients. Many of the findings are in line with those of previous studies looking at this question. Prentice et al. found that the following factors were associated with greater opioid use during the first postoperative year:
- Preoperative opioid use
- Female sex
- Black race
- Higher BMI
- Substance abuse
- Back pain
- Chronic pulmonary disease
For me, the most noteworthy finding was that almost 25% of all patients in the study were still using opioids 271 to 360 days after their operation. That is a much higher percentage than I would have guessed prior to reading this study. Somewhat less surprising but also concerning was the finding that 63% of these patients filled at least 1 opioid prescription in the year prior to their THA, leading the authors to suggest that orthopaedic surgeons “refrain from prescribing opioids preoperatively” or “decrease current opioid users’ preoperative doses.”
Although some readers may be suffering from “opioid fatigue” in the orthopaedic literature, I encourage our community to continue addressing our role in the current opioid crisis. While I believe that we have changed our prescribing practices since the data for this study were collected (2008 through 2011), we cannot dismiss these findings. The opioid epidemic is multifactorial and has many deep-rooted tendrils in our healthcare system. We owe it to our patients and to the public at large to be as significant a part of the solution as possible.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
Early or late dislocation after total hip arthroplasty (THA) is a dreaded complication, and performing a THA to treat a hip fracture is known to increase the risk of postoperative prosthetic joint dislocation. Large-diameter femoral heads, like those used in metal-on-metal implants, offered the prospect of decreased risk of dislocation. Unfortunately, their promise of improved stability was subsequently offset by serious issues with wear. Orthopaedics is notable for technology that promised to solve one problem but led to another, and some wonder whether the increasing popularity of THA using dual-mobility cups to reduce dislocation risk might lead to another example of this paradoxical problem.
However, in the July 17, 2019 issue of The Journal, Jobory et al. published a population-based prospective cohort analysis based on data from the Nordic Arthroplasty Register Association. That study demonstrated a reduced revision risk with dual-mobility acetabular components when THA was performed to treat hip fracture in elderly patients. The authors propensity-score matched 4,520 hip fractures treated with dual-mobility THA to 4,520 hip fractures treated with conventional THA. The study included surgeries from 2001 to 2014, and the median follow-up was 2.4 years for all patients.
Dual-mobility constructs had a lower overall risk of any-component revision (hazard ratio of 0.75), which persisted after authors adjusted for surgical approach (hazard ratio of 0.73). Additionally, the dual-mobility construct had a lower risk of revision due to dislocation (hazard ratio of 0.45), but there was no difference in risk of deep infection between the cohorts. There was no significant difference in risk of any-component revision for aseptic loosening (hazard ratio of 0.544, p=0.052) until the authors adjusted for approach, which resulted in a decreased risk of any-component revision for aseptic loosening (hazard ratio of 0.500, p=0.030). When the authors compared revision of the acetabular component only, they found a reduced risk of revision for any cause as well as revision for dislocation in the dual-mobility cohort using both unadjusted data and data adjusted for surgical approach. Mortality was higher in the dual-mobility group compared with the conventional-component group (hazard ratio of 1.5).
Overall, this study gives us more information regarding the short-term revision risks of an implant design that is gaining popularity in the US. Although dual-mobility constructs seem to be associated with a decreased risk of revision for dislocation in a population of older adults with hip fracture, this data tells us little about this design and technology when used in younger, more active patients, who are at higher risk of polyethylene wear.
Matthew Deren, MD is an orthopaedic surgeon at UMass Memorial Medical Center, an assistant professor at University of Massachusetts Medical School, and a member of the JBJS Social Media Advisory Board.
It has been said that outcomes of total joint arthroplasty are 90% related to surgeon factors (such as prosthetic alignment and fit and soft-tissue management), and only 10% to the implant itself. Historically, surgeon choices of implants for primary total hip and total knee arthroplasty have been based on influences such as the prostheses used during training, prior vendor relationships, specific patient characteristics, and findings in published literature. Absent evidence that the selection of prosthesis vendor affects patient outcomes to any significant degree, and with the universal focus on lowering health care costs, surgeon implant/vendor preferences have come under close scrutiny.
In the August 7, 2019 issue of The Journal, Boylan et al. study the impact of a voluntary preferred single-vendor program at a large, high-volume, urban orthopaedic hospital with >40 (mostly hospital-employed) arthroplasty surgeons. The hospital’s use of hip and knee arthroplasty implants from the preferred vendor rose from 50% to 69% during the program’s first year. In addition, the mean cost per case of cases in which implants from the preferred vendor were used were 23% lower than the mean cost-per-case numbers from the previous year (p<0.001). Boylan et al. noted that low-volume surgeons adopted the initiative at a higher rate than high-volume surgeons, and that surgeons were more compliant with using the preferred vendor for total knee implants than for total hip implants.
Why is it that some higher-volume surgeons seem resistant to change? It is not clear from the data presented in this study whether the answer is familiarity with an instrument system, loyalty to local representatives, or relationships with manufacturers based on financial or personal connections. The authors observed that “collaboration between surgeons and administrators” was a critical success factor in their program, and interestingly, the 3 highest-volume surgeons in this study (who performed an average of ≥20 qualifying cases per month) all used total knee implants from the preferred vendor prior to the initiation of this program.
The provocative findings from this and similar studies lead to many questions ripe for further research. Because hospitals are highly motivated to reduce implant costs in the bundled-payment environment, preferred-vendor programs are gathering steam. We need to better understand how they work (or don’t) for specific surgeons, within surgical departments, and within hospital/insurance systems in order to evaluate their effects on patient outcomes and maximize any cost benefits.
Marc Swiontkowski, MD
In the setting of revision total hip arthroplasty (THA), the use of electrocautery—and contact between the thermal device and retained components—cannot always be avoided. In the May 15, 2019 issue of The Journal of Bone & Joint Surgery, Sonntag et al. perform two implant-retrieval analyses and a separate in vitro investigation to determine what kinds of damage take place when electrocautery energy meets titanium femoral stems.
The components for retrieval analyses were removed from patients who experienced a fracture of the femoral stem or femoral neck after revision THA. The authors found superficial discoloration and melting marks on the retrieved components, and elemental analysis indicated that material had been transferred from the electrocautery tip. During in vitro testing of 6 titanium alloy femoral stems, the authors found that electrocautery surface damage reduced load-to-failure by up to 47% when compared to undamaged femoral neck specimens. Microscopic analysis revealed notable changes in metal microstructure in electrocautery-exposed components, whereby certain zones exhibited higher strength than others, which, the authors speculate, might result in lower overall fatigue resistance.
Both the retrieval and in vitro analyses showed that electrocautery damage to femoral implants, particularly in the anterolateral region at the base of the neck, reduced implant fatigue resistance. However, the authors say their results need to “be carefully interpreted,” because they are based on only 2 retrievals and a limited number of test specimens. Nevertheless, they conclude that “electrocautery device contact [with femoral implants] should be avoided and the use of conventional scalpels is recommended, where reasonable.”
Despite what seems like a new, high-quality study being published on the topic every week or so, orthopaedic surgeons still have an extremely hard time determining whether a prosthetic hip or knee is infected or not. We have an array of available tests and the relatively easy-to-follow criteria for a periprosthetic joint infection (PJI) from the Musculoskeletal Infection Society (MSIS), but a large number of these patients still fall into the gray zone of “possibly infected.” This predicament is especially thorny in patients who received antibiotics just prior to the diagnostic workup, which interferes with the accuracy of many tests for PJI.
In the April 17, 2019 issue of The Journal, Shahi et al. remind orthopaedic surgeons about a valuable tool that can be used in this scenario. Their retrospective study looked at 121 patients who had undergone revision hip or knee arthroplasty due to an MSIS criteria-confirmed periprosthetic infection. Shahi et al. sought to determine which diagnostic tests were least affected by prior antibiotic administration. The authors found that erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, synovial white blood cell (WBC) count, and polymorphonuclear neutrophil (PMN) percentage were all significantly lower in the 32% of patients who had received antibiotics within 2 weeks of those tests, compared with the 68% who did not receive antibiotics. The only test that was found not to be significantly affected by the prior admission of antibiotics was the urine-based leukocyte esterase strip test.
Considering the ease and rapidity with which a leukocyte esterase test can be performed and evaluated (at a patient’s bedside, with immediate results), its low cost, and the fact that it is included in the MSIS criteria, these findings are very important and useful. While we would prefer that patients with a possibly infected total hip or knee not receive antibiotics prior to their diagnostic workup, previous antibiotic exposure remains a relatively common scenario. The findings from this study can assist us in those difficult cases, and they add further evidence to support the value and reliability of the easy-to-perform leukocyte esterase test.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
The indications for treating total hip arthroplasty (THA) dislocations by cementing a constrained polyethylene liner into a well-fixed, retained acetabular component at the time of revision are narrow. That’s largely due to concerns about the durability of the resulting acetabular construct. Now, thanks to a study by Brown et al. in the April 3, 2019 issue of JBJS, hip surgeons have some hard data about the long-term outcomes of this approach.
After reviewing 125 cases in which a constrained liner was cemented into a retained, osseointegrated acetabular component during revision THA, with a mean follow-up of 7 years, the authors found that:
- Survivorship free from revision for instability was 86% at 5 years and 81% at 10 years. The cumulative incidence of instability at 7 years was 18%.
- Survivorship free from aseptic acetabular component revision was 78% at 5 years and 65% at 10 years. The most common failure mechanism was dissociation of the constrained liner from the retained component.
- Harris hip scores (HHS) did not improve significantly after revision. This finding is consistent with prior research that shows better post-revision HHS scores in patients whose revisions include the entire acetabular component.
- Position of the retained cup did not affect implant survivorship or risk of dislocation.
The authors mention alternative strategies for reducing the risk of dislocation after revision THA, such as the use of large-diameter heads and dual-mobility constructs. Still, they conclude that this constrained-liner approach, in the setting of a relatively well-positioned acetabular component, is a viable and durable THA revision option, especially for those “with a compromised abductor mechanism, recurrent instability, [and] a well-fixed and well-positioned acetabular component, for whom an acetabular revision would not be tolerated.”