BOG Fracture-Risk Score Combines DNA Info with Physiological Factors
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.
During childhood and adulthood, we often put ourselves at risk for future fractures based on our activity, diet, and social habits. Many factors affect the risk of both stress fractures in younger people and fragility fractures later in life. Everyone—but especially athletes and active-duty military personnel—could benefit from an early heads-up regarding their genetic and phenotypic predisposition to stress fractures. Later in life, the FRAX index is a very useful multifactor risk score, but it is usually calculated only after a sentinel event, such as a fragility fracture.
Ultrasound is a readily available and inexpensive way to obtain an estimated heel bone mineral density (eBMD). Many common genetic variants contribute to the genetic basis for the eBMD phenotype. These variants are most commonly characterized by single nucleotide polymorphisms (SNPs, pronounced “snips”). Stanford researcher Stuart Kim developed the BMD Osteoporosis Genetic (BOG) risk score by combining 22,886 SNPs with data on height, weight, sex, and age.1 The correlation between actual eBMD and the BOG algorithm was 0.496, which was higher than the correlations achieved using the 22,886 genetic predictors or the four covariates alone.
Individuals with low BOG scores had a 17.4-fold increased risk for osteoporosis compared to those with the median BOG score. Low BOG scores were also associated with a 1.9-fold higher risk for bone fractures compared to median BOG values. However, the algorithm’s ability to discriminate cases from controls in the overall population was modest. The receiver operator area under the curve for predicting osteoporosis or fracture by the BOG algorithm was 0.78 and 0.57, respectively.
Although the effect of an individual SNP may be inconsequential, the cumulative effect from many SNPs can be large. The author stated that “an algorithm such as the BOG risk score might be useful to screen the general population…to identify individuals that warrant closer examination, such as BMD measurement via DXA [dual-energy X-ray absorptiometry].”
Reference
- Kim SK. Identification of 613 new loci associated with heel bone mineral density and a polygenic risk score for bone mineral density, osteoporosis and fracture. PLoS One. 2018 Jul 26;13(7):e0200785. doi: 10.1371/journal.pone.0200785. eCollection 2018. PMID: 30048462
Fracture Liaison Service Boosts Patient Engagement with Secondary Prevention
OrthoBuzz has published several posts about osteoporosis, fragility fractures, and secondary fracture prevention. In the May 17, 2017 edition of JBJS, Bogoch et al. add to evidence suggesting that a coordinator-based fracture liaison service (FLS) improves engagement with secondary-prevention practices among inpatients and outpatients with a fragility fracture.
The Division of Orthopaedic Surgery at the University of Toronto initiated a coordinator-based FLS in 2002 to educate patients with a fragility fracture and refer them for BMD testing and management, including pharmacotherapy if appropriate. Bogoch et al. analyzed key clinical outcomes from 2002 to 2013 among a cohort of 2,191 patients who were not undergoing pharmacotherapy when they initially presented with a fragility fracture.
- Eighty-four percent of inpatients and 85% of outpatients completed BMD tests as recommended.
- Eighty-five percent of inpatients and 79% of outpatients who were referred to follow-up bone health management were assessed by a specialist or primary care physician.
- Among those who attended the referral appointment, 73% of inpatients and 52% of outpatients received a prescription for anti-osteoporosis medication.
The authors conclude that “a coordinator-based fracture liaison service, with an engaged group of orthopaedic surgeons and consultants…achieved a relatively high rate of patient investigation and pharmacotherapy for patients with a fragility fracture.”
Own the Bone Webinar: Atypical Fractures and Osteo Medications
On Thursday, February 23, 2017, at 6:00 pm EST, the Own the Bone initiative will offer a webinar titled “Atypical Fractures and Osteoporosis Medication Considerations”
James Goulet, MD, from the University of Michigan, will discuss atypical fractures and other rare outcomes of the use of osteoporosis medication, including what to look for and how to treat these occurrences. He will also address drug holidays, and how and when to continue treatment on these complex cases.
The American Orthopaedic Association (AOA) developed Own the Bone as a quality improvement program to address the osteoporosis treatment gap and prevent subsequent fragility fractures.
0.75 hour of CME credit is available.
Fracture Liaison Service Addresses Epidemic of Osteoporosis
The statistics about osteoporosis and associated fragility fractures are sobering:
- One-quarter of adults living in the US currently have osteoporosis or low bone density.
- Twenty-four percent of people aged 50 and older who sustain a hip fracture will die within a year after the fracture.
- Patients who have had one fragility fracture have an 86% increased risk for a second fracture.
Amid these troubling data stands hope from an effective, team-based clinical response—the fracture liaison service (FLS). In the April 15, 2015 edition of JBJS, Miller et al . explain how an FLS works and the results it achieves.
The authors define the fracture liaison service as “a coordinated care model of multiple providers who help guide the patient through osteoporosis management after a fragility fracture to help prevent future fractures.” The three key players on the FLS team are a coordinator (usually an advanced-practice provider), a physician champion (whom the authors say should be an orthopaedic surgeon), and a “nurse navigator.” Miller et al. describe the roles these FLS core team members play (including patient care and education and communication with other clinical services and administrators), suggest ways to organizationally justify an FLS, and lay out a stepwise implementation roadmap.
The authors conclude that an FLS “is adaptable to any type of health-care system, improves patient outcomes, and decreases complications and readmissions related to secondary fractures.” And there’s an important fringe benefit: “The FLS can help improve performance on quality measures…and help health-care organizations during this transition from volume payment to quality payment,” they say.
Preventing Atypical Femoral Fractures Related to Bisphosphonates
Physicians worldwide frequently prescribe bisphosphonates such as alendronate (Fosamax) and ibandronate (Boniva) to treat osteoporosis and prevent fragility fractures. Unfortunately, long-term bisphosphonate use has been linked to an increased risk of atypical femoral fractures. In the March 3, 2015 edition of JBJS Reviews, Blood et al. offer some guidance on how to prevent such fractures.
The authors note that prodromal thigh pain and a radiolucent line on X-rays of patients with a history of chronic bisphosphonate use are strong indicators of an impending fracture. Among bisphosphonate users who have an incomplete fracture with little or no pain, the authors recommend a trial of discontinued bisphosphonates, protected weight-bearing, calcium and vitamin-D supplementation, and possible teriparatide (Forteo) therapy. They add that prophylactic fixation should be considered if there is no radiographic or symptomatic improvement after two to three months of that conservative approach. Blood et al. further recommend that patients at high risk for atypical femoral fracture, should consider discontinuing bisphosphonate therapy after five years of continuous use. They also encourage orthopaedists to assess the contralateral femur for signs of impending fracture in patients who have already had an atypical femoral fracture.
The recommendations by Blood et al. notwithstanding, we should stress that the absolute risk of atypical femoral fractures fractures is low (3.2 to 50 cases per 100,000 person-years among short-term bisphosphonate users and about 100 cases per 100,000 person-years among long-term users). Consequently, for most people with osteoporosis, the proven fragility-fracture risk-reduction benefits of bisphosphonates outweigh the risks of atypical femoral fracture.
Readers interested in this subject may want to read a related Case Connections article, which springboards from a January 14, 2015 Case Connector article.
JBJS Editor’s Choice–Distal Radius Fractures in Older Men: Why So Much Publicity?
In my 20-plus years serving as a deputy editor and editor of JBJS, I have never seen the kind of media interest in research published in The Journal that the Harper et al. study on distal radius fractures in older men has received.
This well-done retrospective evaluation of 95 males and 344 females who were treated for a distal radius fracture at a single institution has been discussed in multiple forums and media outlets, including the national newswire services, scientific and clinical blog sites, and health reports on local and national TV newscasts.
One conclusion from the Harper et al. analysis was that males older than 50 who had a distal radius fracture are receiving far worse follow-up care compared to females with the same characteristics in terms of bone-mineral density testing and subsequent pharmacologic treatment to prevent future fractures. For example, an older male with a fragility-caused distal radius fracture is nearly 10 times less likely to undergo bone-density testing than a woman with the same fracture. What is so newsworthy about this finding as to prompt headlines such as “Gender Bias in Osteoporosis Screening”?
My hypothesis is that orthopaedic research has focused too much on procedural-based interventions. When research such as the Harper et al. study extends beyond developing new therapies to matters of population health and application of evidence-based therapies, the public pays especially close attention. Previous OrthoBuzz posts by my JBJS predecessor Vern Tolo, MD and JBJS Reviews Editor-in-Chief Tom Einhorn, MD have called on clinicians to take a more aggressive approach toward primary and secondary prevention of fragility fractures. JBJS commentator Douglas Dirschl, MD says that the gender disparity revealed by Harper et al. “should shock the medical community into improved performance.”
Orthopaedic surgeons are increasingly working in teams consisting of family physicians with additional musculoskeletal training, radiologists, anesthesiologists, nurses, PTs, OTs, and athletic trainers. As our field expands its scope to “musculoskeletal health, prevention, and treatment” and away from exclusively invasive interventions, let’s continue to invite the public along. Based on the media coverage of the Harper et al. study, the public appears to be a willing partner in our attempts to reduce the risk of fragility fractures.
Do you think including preventive and population-health perspectives is the right direction for our field? Send us a comment of support or a dissenting view by clicking on the “Leave a Comment” button in the box to the left.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
EDITOR’S CHOICE: Are We Overtreating Clavicular Fractures?
This is my first Editor’s Choice for OrthoBuzz as new Editor-in-Chief of JBJS. I am following the example of my esteemed predecessor, Vern Tolo, who recently issued an Editor’s Choice warning about our failure to improve the management of patients with fragility fractures in terms of appropriate diagnosis and treatment of underlying osteoporosis. That is a failure of under-treatment. I want to focus on a potential issue of overtreatment.
In the July 2, 2014 JBJS, Leroux et al. describe the risk factors for repeat surgery after ORIF of midshaft clavicle fractures. The study analyzed 1,350 patients treated with surgery between 2002 and 2010 in Ontario. It is important to note that this analysis includes years after 2007, when JBJS published the seminal multicenter RCT on this topic by the Canadian Orthopaedic Trauma Society (COTS). The essence of that study was that ORIF with plate fixation results in a lower rate of nonunion and better functional outcomes predominantly in patients who have completely displaced fractures with about 2 cm of shortening or displacement.
Since that publication, we have seen an explosion in the operative treatment of midshaft clavicle fractures in North America. However, all too often the inclusion criteria derived from the seminal RCT are not referenced in individual patient decision making, and the presence of a clavicle fracture–regardless of degree of displacement–becomes an indication for surgical management.
The findings of the Leroux study should help put a hard stop to this! These researchers found a 24.6% incidence of repeat surgery in this cohort of patients. The most common reoperation was isolated implant removal (18.8%), and the incidence of major complications included nonunion (2.6%), deep infection (2.6%), pneumothoraces (1.2%), and malunion (1.1%). Risk of reoperation was increased in female patients and in those with major medical comorbidities. Limited surgeon experience increased the risk of reoperation for infection.
The orthopaedic surgery community must heed these data and act upon them. We should not misinterpret the COTS study to “encourage” a patient to opt for surgery if he or she has a midshaft clavicle fracture with less than 2 cm of shortening or displacement. The technical aspects of surgery for midshaft clavicle nonunion is not that different than that for a fresh fracture, so avoidance of nonunion must be thoughtfully discussed with the patient before recommending surgical fixation.
The bottom line that Leroux et al. provide is that surgery for a midshaft clavicle fracture is not a guaranteed success and that surgeon experience matters. And beyond clavicle fractures, let’s be sure we use our literature during shared decision making in an accurate and appropriate manner. That is a basic tenet of professionalism that we all should subscribe to.
Owning the Bone in Spine Surgery
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.
Approximately 20% of patients who undergo spine surgery have osteoporosis, which has a significant impact on spine-surgery complications such as failure of fixation devices and collapse fractures following fusion procedures. In a recent critical analysis review, authors focus on improving outcomes by identifying and optimizing patients with osteoporosis prior to spine surgery. The multidisciplinary team involved in that process should include primary care providers, endocrinologists, physical therapists, and orthopaedic surgeons.
The predominant tool for assessing bone mineral density (BMD) is dual x-ray absorptiometry. The diagnosis is based on a T score, which represents the number of standard deviations between the patient’s BMD and that of a healthy 30-year-old woman. Standard deviations ≤─2.5 define osteoporosis. The Z score is similar to the T score but compares the patient to an age- and sex-matched individual.
A history of low-energy fracture, such as a wrist fracture following a fall from a standing height, is considered a sentinel event for suspicion of fragility fractures. The combination of a fragility fracture and low BMD is considered to be severe osteoporosis. The most common form of osteoporosis is associated with a postmenopausal decrease in mineralization, but there are other causes. These include advanced kidney disease, hypogonadism, Cushing disease, vitamin D deficiency, anorexia and/or bulimia, rheumatoid arthritis, hyperthyroidism, primary hyperparathyroidism, and some medications (e.g., anticonvulsants, corticosteroids, heparin, and proton pump inhibitors).
Forty-seven percent of patients undergoing spine deformity surgery and 64% of cervical spine surgery patients have low vitamin D levels. Postoperative bone health can be enhanced in women ≥51 years old with daily intake of 800 to 1,000 units of vitamin D and 1,200 mg of daily calcium. There is no solid evidence that pre- or postoperative bisphosphonates have a positive impact on bone healing. Conversely, some series have shown that teriparatide, an anabolic parathyroid hormone, may improve time-to-fusion and help reduce screw pull-out after lumbar fusion in postmenopausal women.
Calcitonin has been shown to reduce the incidence of vertebral compression fracture, but there is no concrete evidence that it supports spine-fusion healing. Similarly, there is no strong evidence for the use of estrogen or selective estrogen receptor modulators in this surgical scenario. There is evidence that when the human monoclonal antibody denosumab is combined with teriparatide, spine-fusion healing may be improved relative to the use of teriparatide alone. Finally, the review article identifies screw size, screw position, and other surgical considerations that can improve fixation strength.
Using the “Own the Bone” practices promulgated by the American Orthopaedic Association and the technical considerations described in this review, we should be able to mitigate osteoporosis-related postoperative complications in spine-surgery patients.
Using CT Data to Diagnose Osteoporosis
Osteoporosis is a “silent” disease, often becoming apparent only after a patient older than 50 sustains a low-energy fracture of the wrist, proximal humerus, or hip. Monitoring serum vitamin D levels and DEXA testing represent ideal screening methods to prevent these sentinel fragility fractures. In addition, through programs such as the AOA’s “Own the Bone” initiative, the orthopaedic community has taken a leadership role in diagnosing and treating osteoporosis after the disease presents as a fragility fracture. Own the Bone is active in all 50 states and, through local physician leadership, is identifying individuals who present with a fragility fracture so they can receive follow-up care that helps mitigate bone loss and prevent secondary fractures.
We still have a long way to go, however. Recent analyses show that only 30% of candidate patients (albeit up from 20%) are receiving this type of evidence-based care. The best-case scenario would be to identify at-risk men and women (osteoporosis does not affect women exclusively) before a potentially serious injury.
In the December 5, 2018 issue of The Journal, Anderson et al. present strong evidence that computed tomography (CT) can provide accurate data for diagnosing osteoporosis. CT is increasingly used (perhaps overused in some settings) across a spectrum of diagnostic investigations. The osseous-related data from these scans can be used to glean accurate information regarding a patient’s bone quality by analyzing the Hounsfield unit (HU) values of bone captured opportunistically by CT. HU data are routinely ignored, but the values correlate strongly with bone mineral density, and they could help us recommend preventive care to our patients before a fragility fracture occurs. (For example, a threshold of <135 HU for the L1 vertebral body indicates a risk for osteoporosis.)
Orthopaedists should discuss the possibility of asking their radiologist colleagues who read CT scans of older patients to routinely share that data. When indicated, we could promptly refer patients back to their primary care provider for discussion of pharmacological treatment and lifestyle changes proven to help prevent primary fragility fractures. There is little doubt that our patients are getting older. Reviewing CT data could help us dramatically improve preventive care and decrease the risk of first-time fragility fractures.
Click here for additional OrthoBuzz posts about fragility fractures.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
Less Pain, More Gain with Just One Screw
Image courtesy of AO Surgery Reference
OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Matthew Herring, MD in response to a recent study in the Journal of Orthopaedic Trauma.
Low-energy sacral fractures in the geriatric population typically heal over time without operative intervention. Nonoperative treatment usually involves analgesics and progressive rehabilitation. Unfortunately, given the frailty and low physiologic reserves of many in this patient population, these fractures can still take a significant toll. Fracture pain may last for weeks to months; deconditioning occurs secondary to poor mobilization; and many patients are discharged to skilled nursing facilities rather than returning directly home.
Given this associated morbidity, Walker et al.1 asked whether percutaneous transiliac-transsacral screw fixation could offer some benefit in the treatment of sacral fragility fractures. The authors present a retrospective review of 41 elderly patients who were admitted with sacral fragility fractures. All patients first received a trial of nonoperative management, which included analgesia and physical therapy-guided mobilization. If patients were unable to appropriately ambulate secondary to pain, they were offered surgery. Sixteen patients elected surgery, which consisted of transiliac-transsacral screw fixation of the posterior pelvic ring.
After surgery, the operative group reported greater reductions in pain than the nonoperative cohort, and they were more likely to be discharged directly home from the hospital (75% versus 20%). Furthermore, at the time of discharge, 100% of the surgical patients were able to ambulate with physical therapy, compared to only 72% of the nonoperative group. No surgical complications occurred, and the average total surgical time was only 34 minutes.
Sacral fragility fractures can result in significant pain and disability in an already frail population. While these fractures are typically managed conservatively, this study suggests that some patients may benefit from surgical intervention. Percutaneous transiliac-transsacral screw fixation is a relatively low-risk procedure (at least in the normomorphic sacrum). And if a single screw can reduce pain, improve function, and more quickly return geriatric patients to their baseline level of independence, then the risk-benefit calculus would favor surgery, unless specific contraindications are present.
While this study is not powerful enough to rewrite treatment protocols, it does give credence to considering surgical fixation for sacral fragility fractures in those who still struggle after a trial of conservative management, and it makes a strong argument for further investigation.
Matthew Herring, MD is a fellow in orthopaedic trauma at the University of California, San Francisco and a member of the JBJS Social Media Advisory Board.
Reference
- Walker, J. Brock, et al. “Percutaneous Transiliac–Transsacral Screw Fixation of Sacral Fragility Fractures Improves Pain, Ambulation, and Rate of Disposition to Home.” Journal of orthopaedic trauma 32.9 (2018): 452-456.
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