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Dashboard Depicts Surgeon-Level Value of TKA/THA

Remember when a “dashboard” referred to the display just behind a car’s steering wheel? In today’s digital universe, the word has come to mean any number of visual information displays. At the same time, the meaning of the word “value” has narrowed somewhat. In relation to health care, “value” is defined quite precisely as the quality of patient outcomes per dollar spent on healthcare services.

In the November 4, 2020 issue of The Journal of Bone & Joint Surgery, Reilly et al. explain how they created a “value dashboard” for total hip and knee arthroplasty (THA and TKA) at a tertiary-care medical center in New England. The goal: track and display the surgeon-level cost and quality of these procedures against institutional benchmarks to identify opportunities for improving value.

The 7 quality metrics that Reilly et al. used included both clinical and patient-reported outcomes, weighted by surgeons using a modified Delphi process. Average direct costs per surgeon were calculated from the medical center’s billing system, and data were collected over a 15-month period from 2017 to 2018 to ensure at least 1 year of outcomes. Six surgeons were included in the TKA value dashboard, and 5 were included in the THA dashboard.

Relative to the institutional benchmarks:

  • Value for TKA by surgeon ranged from 7% below benchmark to 12% above.
  • Value for THA by surgeon ranged from 12% below benchmark to 7% above.

The dashboard itself (see Figure above) displays quality, cost, and overall value so viewers can see at a glance which metrics are driving the value score for each surgeon, whose procedural volume is also depicted. The authors cite as one limitation of this study the fact that the quality metrics were weighted by local surgeons only, and they say that “ideally the weighting would be informed by a panel of national experts and several stakeholder groups,… including patients.”

Time Waits For No One—Aging Increases Costs

The cost of medical care in the United States has been shown to rise with advancing patient age, and total joint arthroplasty (TJA) is a prime example of this unsurprising phenomenon. In attempts to curtail costs and reduce variability, Medicare and other payers have introduced alternative payment models (APMs), such as the Bundled Payments for Care Improvement (BPCI) initiative. In this model’s application to TJA, when participating institutions keep the cost of the “episode” below a risk-adjusted target price, they accrue the savings as a profit, but they sustain a financial penalty if the episode costs more than the target price.

Multiple studies have suggested that APMs can negatively affect the fiscal health of institutions that care for many high-risk patients. Although increasing age has been associated with higher-cost episodes of care, age is not one of the factors that the BPCI model accounts for. Consequently, concerns have been raised that providers may practice “cost discrimination” against very old patients.

In the October 7, 2020 issue of The Journal, Petersen et al. examine how an aging population has affected a New York City orthopaedic center in terms of the BPCI model applied to TJA. The authors analyzed the relationship between patient age and cost of care among 1,662 patients who underwent primary total hip and knee arthroplasty over a 3-year period under BPCI. They then used a modeling tool to predict shifting age demographics for their local area out to the year 2040.

Petersen et al. found that under BPCI, their institution sustained a nearly $2,000-per-case loss for TJA care episodes among patients 85 to 99 years of age. Currently this loss is offset by profits realized by performing TJAs in younger patients. However, predictive modeling identified an inflection point of 2030, after which a relative increase in older patients and a decrease in younger patients will yield an overall net decrease in profits for primary TJA.

Because no one, including orthopaedic surgeons, can turn back the clock on aging, health care stakeholders must find ways either to adjust downward the cost of care for the elderly (seemingly difficult without adversely affecting outcomes) or adjust reimbursement models to account for the increased costs associated with aging. I agree with the conclusion of Petersen et al.: “The BPCI initiative and [other] novel APMs should consider age as a modifier for reimbursement to incentivize care for the more vulnerable and costly age groups in the future.”

Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media

The Importance of a “Well-Rounded” Hip

This post 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.

Fifty years ago, the precise etiology of hip osteoarthritis (OA) was not clear. In 1976, Solomon proposed 3 potential causes of osteoarthritis in general:1

  1. Failure of essentially normal cartilage subjected to abnormal or incongruous loading for long periods
  2. Damaged or defective cartilage failing under normal conditions of loading
  3. Breakup of articular cartilage due to defective subchondral bone

In 1986, Harris expanded on this concept by noting that mild acetabular dysplasia and/or pistol grip deformity were associated with 90% of patients who had “so-called primary or idiopathic” hip OA.2 Harris further claimed that “when these abnormalities are taken in conjunction with the detection of other metabolic abnormalities that can lead to osteoarthritis of the hip,…it seems clear that either osteoarthritis of the hip does not exist at all as a primary disease entity or, if it does, is extraordinarily rare.”

Subsequently, acetabular dysplasia was defined as an acetabular shape where the lateral center edge angle (LCEA) was <25°, and the cam and pincer deformities were introduced as forms of acetabular dysplasia. Acetabular retroversion, as detected by the crossover sign seen in anterolateral hip radiographs, was recognized later, and Tonnis used CT imaging to determine acetabular and femoral anteversion.3

In 2020, investigators suspected that zonal-acetabular radius of curvature (ZARC) might play a role in hip-joint shape disorders.4 ZARC is the radius of curvature of the articular contact surface (from the margin of the fovea centralis to the acetabular rim), and the authors analyzed ZARC in anterior, superior, and posterior zones in subjects with normal, borderline, and dysplastic hips. (“Normal” was defined as LCEA of 25° to <40°; “borderline” as LCEA of 20° to <25°; and “dysplastic” as LCEA of <20°.) The 3-zone ZARC findings are summarized in the table below.

Mean Zonal-Acetabular Radius of Curvature (ZARC)

ZARC Zone Borderline Normal Dysplasia
Anterior 29.8 +/- 2.6 mm 28.0 +/- 2.2 mm 31.5 +/- 2.7 mm *
Superior 25.7 +/- 3.0 mm 25.9 +/- 2.2 mm 25.8 +/- 2.5 mm
Posterior 27.2 +/- 2.5 mm 26.4 +/- 1.9 mm 30.4 +/- 3.3 mm *

* P < 0.01

In this study, the severity of lateral undercoverage affected the anterior and/or posterior zonal-acetabular curvature. The take home message is that, absent metabolic abnormalities, acetabular and femoral head congruity and orientation are the driving forces in hip OA.

References

  1. Solomon L. Patterns of osteoarthritis of the hip. J Bone Joint Surg Br. 1976;58(2):176-83. Epub 1976/05/01. PubMed PMID: 932079.
  2. Harris WH. Etiology of osteoarthritis of the hip. Clinical orthopaedics and related research. 1986(213):20-33. Epub 1986/12/01. PubMed PMID: 3780093.
  3. Tonnis D, Heinecke A. Acetabular and femoral anteversion: relationship with osteoarthritis of the hip. J Bone Joint Surg Am. 1999;81(12):1747-70. Epub 1999/12/23. PubMed PMID: 10608388.
  4. Irie T, Espinoza Orias AA, Irie TY, Nho SJ, Takahashi D, Iwasaki N, et al. Three-dimensional hip joint congruity evaluation of the borderline dysplasia: Zonal-acetabular radius of curvature. J Orthop Res. 2020;38(10):2197-205. Epub 2020/02/20. doi: 10.1002/jor.24631. PubMed PMID: 32073168.

What’s New in Hip Replacement 2020

Every month, JBJS reviews 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, PhD, co-author of the September 16, 2020 What’s New in Hip Replacement,” selected the five most clinically compelling findings from among the 95 noteworthy studies summarized in the article.

Medical Comorbidities and Outcomes of Joint Arthroplasty
–Among 543 malnourished joint arthroplasty patients (with albumin levels <3.4 g/L), an intervention encouraging  a high-protein, anti-inflammatory diet shortened the length of hospital stay and lowered readmissions, relative to malnourished arthroplasty patients who did not receive the intervention.1

Surgical Factors and Outcomes of Total Hip Arthroplasty (THA)
–A multicenter, prospective study used propensity-score matching to compare THA performed with a direct anterior approach with THA performed with a posterolateral approach. Researchers found no patient-reported outcome differences at 1.5 months postoperatively or at ≥1 year up to 5 years.2

Periprosthetic Joint Infection (PJI)
A Musculoskeletal Infection Society workgroup published a recommendation for a 4-tier tool for reporting outcomes after surgical treatment of PJI. Proposed outcomes include infection control with no antibiotic treatment, infection control with suppressive antibiotic therapy, need for reoperation and/or revision and/or spacer retention, and death.

–A meta-analysis found only low-quality retrospective evidence supporting the practice of routinely applying intrawound vancomycin to reduce the rates of PJI. Authors called for a prospective randomized trial before adoption of this practice.3

Postoperative Urinary Retention
–A randomized controlled trial found that preoperative and perioperative administration of tamsulosin did not reduce the incidence of postoperative urinary retention after hip and knee arthroplasty. However, the study included a general male population rather than a higher-risk group.4

References

  1. Schroer WC, LeMarr AR, Mills K, Childress AL, Morton DJ, Reedy ME. 2019 Chitranjan S. Ranawat Award: elective joint arthroplasty outcomes improve in malnourished patients with nutritional intervention: a prospective population analysis demonstrates a modifiable risk factor. Bone Joint J.2019 Jul;101-B(7_Supple_C):17-21.
  2. Sauder N, Vestergaard V, Siddiqui S, Galea VP, Bragdon CR, Malchau H, Elsharkawy KA, Huddleston JI 3rd, Emerson RH. The AAHKS Clinical Research Award: no evidence for superior patient-reported outcome scores after total hip arthroplasty with the direct anterior approach at 1.5 months postoperatively, and through a 5-year follow-up. J Arthroplasty.2020 Feb 12.
  3. Heckmann ND, Mayfield CK, Culvern CN, Oakes DA, Lieberman JR, Della Valle CJ. Systematic review and meta-analysis of intrawound vancomycin in total hip and total knee arthroplasty: a call for a prospective randomized trial. J Arthroplasty.2019 Aug;34(8):1815-22. Epub 2019 Apr 1.
  4. Schubert MF, Thomas JR, Gagnier JJ, McCarthy CM, Lee JJ, Urquhart AG, Pour AE. The AAHKS Clinical Research Award: prophylactic tamsulosin does not reduce the risk of urinary retention following lower extremity arthroplasty: a double-blinded randomized controlled trial. J Arthroplasty.2019 Jul;34(7S):S17-23. Epub 2019 Mar 20.

Nontraumatic Osteonecrosis: An Early Target for Gene Therapy

As osteonecrosis of the femoral head (ONFH) progresses, it can impair a patient’s ability to walk, and hip arthroplasty is often the only effective long-term option. Other interventions to relieve the pain of ONFH include surgical decompression of the femoral head, which is generally effective but often does not change the natural history of the process. Once the femoral head collapses and loses sphericity, degenerative arthritis of the hip follows quickly. Well-documented risk factors for ONFH include excessive alcohol consumption and corticosteroid use. But why do some patients with these risk factors develop osteonecrosis, while others do not.

In the September 16, 2020 issue of The Journal, Zhang et al. address that clinical quandary with a genomewide association study on a chart-reviewed cohort of 118 patients with ONFH and >56,000 controls. The findings shed light on what is obviously a condition with multifactorial etiology and complex gene-environment interactions. The case-control study identified 1 gene (PPARGC1B) and 4 single nucleotide variants associated with ONFH overall, and with 2 subgroups—those exposed to corticosteroids and those with femoral head collapse. Steroid intake was highly prevalent in both cohorts—90.7% of the ONFH patients had at least one 3-week course of corticosteroids, compared with 68.3% of controls.

For readers interested in the detailed genetic bases for osteonecrosis, this study offers a treasure trove of data. But for all of us, these findings, after they are verified in other populations, may very well form the basis for pharmacologic and gene-modifying strategies in patients at risk for ONFH. Moreover, osteonecrosis of the femoral head is just one of many musculoskeletal conditions that can probably be addressed with this type of genome-based research strategy.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

Treating Developmental Hip Dislocations Diagnosed after Walking Age

There is a wry saying in academic medicine that “nothing ruins good results like long-term follow-up.” But long-term follow-up helps us truly understand how our orthopaedic interventions affect patients. This is especially important with procedures on children, and the orthopaedic surgeons at the University of Iowa have been masterful with long-term outcome analysis in pediatric orthopaedics. They demonstrate that again in the August 5, 2020 issue of The Journal, as Scott et al. present their results comparing outcomes among 2 cohorts of patients who underwent treatment for developmental hip dislocations between the ages of 18 months and 5 years—and who were followed for a minimum of 40 years.

Seventy-eight hips in 58 patients underwent open reduction with Salter innominate osteotomy, and 58 hips in 45 patients were treated with closed reduction. At 48 years after reduction, 29 (50%) of the hips in the closed reduction cohort had undergone total hip arthroplasty (THA), compared to 24 (31%) of hips in the open reduction + osteotomy group. This rate of progression to THA nearly doubled compared to previously reported results at 40 years of follow-up, when 29% of hips in the closed reduction group and 14% of hips in the open reduction group had been replaced.

In addition, the authors found that patient age at the time of reduction and presence of unilateral or bilateral disease affected outcomes. Patients with bilateral disease who were treated at 18 months of age had a much lower rate of progression to THA when treated with closed reduction, compared to those treated with open reduction—but the opposite was true among patients with bilateral disease treated at 36 months of age. Treatment type and age did not seem to substantially affect hip survival among those with unilateral disease.

I commend the authors for their dedication to analyzing truly long-term follow-up data to help us understand treatment outcomes among late-diagnosed developmental hip dislocations in kids. Long-term follow-up may “ruin” good results, but it gives us more accurate and useful results. And, in this case, the findings reminded us how important it is to diagnose and treat developmental hip dislocations as early in a child’s life as possible.

Read the JBJS Clinical Summary about this topic.

Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media

Less Drinking/Smoking Associated with Fewer Hip Fractures

OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Shahriar Rahman, MS in response to a recent study in JAMA Internal Medicine.

Hip fractures are an important cause of morbidity and mortality among the elderly population worldwide. However, age-adjusted hip fracture incidence has decreased in the US over the last 2 decades. While many attribute the decline to improved osteoporosis treatment, the definitive cause remains unknown. A population-based cohort study of participants in the Framingham Heart Study prospectively followed a cohort of >10,000 patients for the first hip fracture between 1970 and 2010.

The age-adjusted incidence of hip fracture decreased by 4.4% per year during this study period. That decrease in hip fracture incidence was coincident with a decrease over those same 4 decades in rates of smoking (from 38% in 1970 to 15% by 2010) and heavy drinking (from 7% to 4.5%), with subjects born more recently having a lower incidence of hip fracture for a given age. Meanwhile, during the study period, the prevalence of other hip-fracture risk factors–such as being underweight, being obese, and experiencing early menopause–remained stable.

This study’s findings should be interpreted in light of 2 major limitations. First of all, there was a lack of contemporaneous bone mineral density data across the study period; secondly, all the study subjects were white. Nevertheless, these findings should encourage physicians to continue carefully managing patients who have osteoporosis and at the same time caution them against smoking and heavy drinking.

Shahriar Rahman, MS is an assistant professor of orthopaedics and traumatology at the Dhaka Medical College and Hospital in Bangladesh and a member of the JBJS Social Media Advisory Board.

What’s New in Musculoskeletal Infection 2020

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, Thomas K. Fehring, MD, co-author of the July 15, 2020 What’s New in Musculoskeletal Infection,” selected the five most clinically compelling findings—all focused on periprosthetic joint infection (PJI)—from among the more than 80 noteworthy studies summarized in the article.

PJI Prevention
–A retrospective case-control study1 found that patients who received an allogeneic blood transfusion during or after knee or hip replacement had a higher risk of PJI than those who were not transfused.

PJI Diagnosis
–A retrospective review2 found that using inflammatory markers to diagnose PJI in immunosuppressed joint-replacement patients is not suitable and that newly described thresholds for synovial cell count and differential have better operative characteristics.

Treating PJI
–A retrospective review3 of a 2-stage debridement protocol with component retention in 83 joint-replacement patients showed an 86.7% success rate of infection control at an average follow-up of 41 months.

–A single-center study4 of perioperative antibiotic selection for patients undergoing total joint arthroplasty found that the risk of PJI was 32% lower among those who received cefazolin compared with those who received other antimicrobial agents. The findings emphasize the importance of preoperative allergy testing in patients with stated beta-lactam allergies.

–A review of regional and state antibiograms5 showed that 75% of methicillin-sensitive S. aureus (MSSA) isolates and 60% of both methicillin-resistant S. aureus (MRSA) and coagulase-negative Staphylococcus isolates were susceptible to clindamycin, whereas 99% of all isolates were susceptible to vancomycin.

References

  1. Taneja A, El-Bakoury A, Khong H, Railton P, Sharma R, Johnston KD, Puloski S, Smith C, Powell J. Association between allogeneic blood transfusion and wound infection after total hip or knee arthroplasty: a retrospective case-control study. J Bone Jt Infect. 2019 Apr 20;4(2):99-105.
  2. Lazarides AL, Vovos TJ, Reddy GB, Kildow BJ, Wellman SS, Jiranek WA, Seyler TM. Traditional laboratory markers hold low diagnostic utility for immunosuppressed patients with periprosthetic joint infections. J Arthroplasty.2019 Jul;34(7):1441-5. Epub 2019 Mar 12.
  3. Chung AS, Niesen MC, Graber TJ, Schwartz AJ, Beauchamp CP, Clarke HD, Spangehl MJ. Two-stage debridement with prosthesis retention for acute periprosthetic joint infections. J Arthroplasty.2019 Jun;34(6):1207-13. Epub 2019 Feb 16.
  4. Wyles CC, Hevesi M, Osmon DR, Park MA, Habermann EB, Lewallen DG, Berry DJ, Sierra RJ. 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.
  5. Nodzo SR, Boyle KK, Frisch NB. Nationwide organism susceptibility patterns to common preoperative prophylactic antibiotics: what are we covering? J Arthroplasty.2019 Jul;34(7S):S302-6. Epub 2019 Jan 17.

Complex Reconstructions Call for Creative Solutions

Metastatic disease around the acetabulum often leads to patients needing total hip arthroplasty (THA), plus supplementary acetabular reconstruction. Traditional methods such as the Harrington reconstruction technique have shown good short-term outcomes, but there are concerns that a cemented acetabular component in this setting is at risk for failure in the longer term. Newer approaches, such as using cementless tantalum acetabular components with augments, have also shown promise. Houdek et al. compared these 2 approaches and report the findings in the July 15, 2020 issue of The Journal.

The authors followed 115 patients who underwent THA for metastatic disease at 2 tertiary sarcoma centers, with a mean 4-year follow-up among surviving patients. They compared the outcomes of 78 Harrington reconstructions with those of 37 tantalum reconstructions, with surgeons at each center exclusively performing 1 of the 2 techniques. The cohorts were comparable at baseline regarding age, sex, severity of systemic disease and acetabular defects, and pelvic discontinuity. Functional outcomes improved in both groups, but there were no significant between-group differences. The main statistical finding of the study was that a higher percentage of patients in the Harrington reconstruction group (27%) needed a reoperation than those in the tantalum group (8%), with a hazard ratio of 4.59 (p=0.003).

Historically, there has been an understandable lack of long-term follow-up in this fragile patient population; 94 of the 115 patients in this study died of systemic disease progression at an average of 16 months after surgery. Overall patient survival was only 34% at 2 years and 15% at 10 years. Despite these grim mortality numbers, Houdek et al. claim that with advances in treatments for metastatic cancer, patients are living longer and therefore may benefit from more durable acetabular reconstructions.

This study leaves unanswered the question of whether the theoretic advantage of bony ingrowth with tantalum is what accounted for the decreased reoperation rates. As Albert Aboulafia, MD notes in his Commentary on this study, the authors did not review radiographs or postmortem histology to look for evidence of osseointegration. But Houdek et al. do present a potential avenue for further investigation. And what remains clear is that metastatic disease around the hip is a complex problem, and that we as surgeons should continue to investigate promising treatment strategies to improve patient outcomes (even if only palliative) and enhance biological fixation.

Click here for a 4-minute video in which co-author Matthew Houdek explains the rationale for this study.

Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media

Questions About Survival of Ultraporous Cups in THA

Acetabular components for primary total hip arthroplasty (THA) made with ultraporous surfaces were developed to enhance osseointegration and biological fixation. In the July 1, 2020 issue of The Journal of Bone & Joint Surgery, Palomaki et al. report on a registry study that suggests that implant survival with these components over an average follow-up of 3.6 years is not so “ultra.”

The authors evaluated >6,000 primary THAs that used a Tritanium ultraporous cup and >25,000 THAs that used a conventional cup, all performed between 2009 and 2017. When they compared the two groups for revision for any reason, the 5-year Kaplan-Meier survivorship of the Tritanium group (94.7%) was inferior to that of the conventional-cup group (96.0%). When revision for aseptic loosening was examined, the 5-year survivorship was also inferior for the Tritanium group (99.0%) compared with the conventional group (99.9%). Regression analysis revealed that the Tritanium group had a much higher risk of revision for aseptic loosening 2 to 4 years after surgery (hazard ratio, 11.2; p <0.001). Interestingly, these survivorship and risk-of-revision differences disappeared when the authors analyzed data for the period from May 15, 2014 to December 31, 2017–when the registry was updated to include patient BMI and ASA-class data.

The authors cite several caveats that readers should apply to these findings. The registry did not capture radiographic findings for these patients, so potentially relevant imaging data could not be analyzed. And, despite the database upgrade in 2014, there was a dearth of available data on patient comorbidities. Finally, wide confidence intervals for some of the hazard-ratio calculations suggest the need to confirm revision-risk findings with further research.

Limitations notwithstanding, the study by Palomaki et al. suggests that the performance of ultraporous cups may not meet the hopes and expectations of hip surgeons and their patients.