Archive | August 2019

Not Your Grandparent’s Journal Club

OrthoBuzz occasionally receives posts from guest bloggers. The following commentary comes from Matthew R. Schmitz, MD, FAOA.

Medical education is a constant need, but how it’s delivered is always changing. When my grandfather was a surgeon, medical trainees brought their dusty textbooks and print journals to “fireside chats” at an attending’s home. Today, we have online journals, tablets and smartphones, podcasts, and “virtual” discussions on social media platforms. Although the technologies evolve, the need to discuss present and past literature remains constant.

These discussions often taken place nowadays through journal clubs. Medical residents across the continent routinely get together in formal or informal settings to discuss journal articles, not only to acquire the knowledge contained in the articles themselves, but also to learn how to properly read, critique, and digest the information.

JBJS provides medical education across multiple platforms, several of which I participate in. I strongly encourage residency programs to submit an application for the 2019-2020 JBJS Robert Bucholz Resident Journal Club Grant Program before the deadline of September 30, 2019. The grant allows medical educators to support their journal clubs in many ways:

  • Investigating new and innovative alternatives to the traditional journal club.
  • Bringing an author to your institution to discuss his or her articles.
  • Hosting a virtual journal club with multiple authors via teleconference or social media.
  • Purchasing food and refreshments within the “old school” method of a fireside chat at an attending’s home.

No matter the platform or methodology, journal clubs are a vital part of orthopaedic education, not only for interpreting literature, but also for incorporating knowledge into future clinical practice and for the joy and excitement of lifelong learning.

Matthew R. Schmitz, MD, FAOA is an orthopaedic surgeon specializing in adolescent sports and young adult hip preservation at the San Antonio Military Medical Center in San Antonio, TX. He is also a member of the JBJS Social Media Advisory Board.

Who Doesn’t Have a Screw Loose?

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.

Fracture fixation with a plate and screws has been around for a century—and so has the problem of screw loosening. Part of the cause of screw loosening seems to be toggling caused by radial forces arising from plate micromotion. Several decades ago, locked screws were designed to prevent loosening and provide better fixation, but screws still loosen.

Two tests can predict screw loosening associated with bone microfracture and absorption: axial pullout stress and toggling radial stress. Recent studies have investigated two hypotheses: radial stress is a predominant cause of screw loosening, and bone resorption is triggered by high radial stress.

Finite Element Analyses

A finite elemental model was used to replicate fixation of a tibial fracture with a 3-mm gap using either a dynamic compression plate (DCP) or locking compression plate (LCP).1 The model included contact with bone, tension on screw insertion, and the placement of two inner screws and one outer screw on either side of the fracture for an 8-hole plate. Axial loading, torsional loading, and bending were applied. Forces exceeding 55 megapascal (MPa) were considered adequate to cause microfracture, whether by radial or axial force. (For reference, 55 MPa is just about 8,000 pounds per square inch.)

The principal finding was that more bone was damaged by radial than by axial stress in both types of plates. Both plate types had more bone damaged by radial stress at the central two screws than at the two end screws for all bending models.

Radiographic Analyses

A separate study evaluated clinical radiographs of fixation for humeral, radial, ulnar, femoral, and tibial shaft fractures. Researchers looked for screw migration or bone absorption of  ≥1 mm around the screw. Both DCPs and LCPs were reviewed.

Researchers found that the outer screws loosened only after the inner screws loosened. There were 3 cases of bone loss with no loosening, 17 cases of bone loss with screw displacement, and no cases of screw loosening without bone loss. This strongly suggests that bone loss must occur for loosening to take place and that the earliest screw loosening occurs closer to the facture site.

Taken together, these results imply that the use of larger inner screws and/or the use of a different angle of fixation might reduce bone absorption that leads to loosening. In addition, radial stress testing might be more important than axial testing. Still, LCPs remain superior at resisting axial loading and bending moments, while DCPs remain superior at resisting torsional loading of unstable fractures.

Reference

  1. Feng X, Lin G, Fang CX, Lu WW, Chen B, Leung FKL. Bone resorption triggered by high radial stress: The mechanism of screw loosening in plate fixation of long bone fractures. J Orthop Res. 2019 Jul;37(7):1498-1507. doi: 10.1002/jor.24286. Epub 2019 Apr 8 PMID: 30908687

What’s New in Limb Lengthening and Deformity Correction 2019

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, Mark T. Dahl, MD, co-author of the August 21, 2019 What’s New in Limb Lengthening and Deformity Correction,” selected the five most clinically compelling findings from among the 40 noteworthy studies summarized in the article.

Congenital Pseudarthrosis
–Authors of a retrospective study of 119 patients with Crawford type-II congenital pseudarthrosis of the tibia found a 69% union rate at maturity. They did not identify specific factors influencing rates of union or refracture, however.1

3-Dimensional Printing
–The models created with this technology can help surgeons preoperatively assess specific anatomical geometries. Corona et al.2 used 3-D-printed titanium truss cages, along with the Masquelet technique, to treat massive infected posttraumatic defects.

Growth Prediction in Limb Lengthening
–A comparative evaluation of the predictive accuracy of 4 methods to correctly time epiphysiodesis in 77 patients found the multiplier method to be the least accurate. In a separate study of 863 epiphysiodeses, authors reported a 7% complication rate.3 The most common complication was incomplete arrest that resulted in angular deformities; half of those cases required reoperation.

Congenital Limb Deficiencies
–Over 16 years, Finnish children born with lower-limb deficiencies had 6 times the number of hospital admissions and 10 times the number of days in hospital per child, compared with children born without a limb deficiency.4

References

  1. Shah H, Joseph B, Nair BVS, Kotian DB, Choi IH, Richards BS, Johnston C, Madhuri V, Dobbs MB, Dahl M. What factors influence union and refracture of congenital pseudarthrosis of the tibia? A multicenter long-term study. J Pediatr Orthop. 2018 Jul;38(6):e332-7.
  2. Corona PS, Vicente M, Tetsworth K, Glatt V. Preliminary results using patient-specific 3D printed models to improve preoperative planning for correction of post-traumatic tibial deformities with circular frames. Injury. 2018 Sep;49(Suppl 2):S51-9.
  3. Makarov MR, Dunn SH, Singer DE, Rathjen KE, Ramo BA, Chukwunyerenwa CK, Birch JG. Complications associated with epiphysiodesis for management of leg length discrepancy. J Pediatr Orthop. 2018 Aug;38(7):370-4.
  4. Syvänen J, Helenius I, Koskimies-Virta E, Ritvanen A, Hurme S, Nietosvaara Y. Hospital admissions and surgical treatment of children with lower-limb deficiency in Finland. Scand J Surg. 2018 Nov 19:1457496918812233. [Epub ahead of print]

Dual-Mobility Cups Lower Revision Risk in Some THAs

OrthoBuzz occasionally receives posts from guest bloggers. In response to a recent study in The Journal of Bone & Joint Surgerythe following commentary comes from Matthew Deren, MD.

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’s So Broken!”

Understanding the mechanism behind a bone fracture helps orthopaedic surgeons select the best approach to reduction and fixation. But patients who present emergently and in great pain are often not able to articulate exactly what happened. Furthermore, when the orthopaedic literature describes mechanisms of injury in words, such as “a high-energy abduction and external rotation of the ankle…,” it leaves a lot to the imagination.

The cell-phone video below had the unintended positive consequence of helping the orthopaedic surgeon understand how this ankle injury—a Weber Type C high fibula fracture, with a spiral pattern, a posterior butterfly, and a large posterior malleolus fracture involving 40% of the articular surface—came about.

The injury was treated using a posterolateral approach to the posterior malleolus. Lag screw fixation was followed by posterior plating of the Weber C level fibula fracture. The syndesmosis was found to be intact during intraoperative testing, and the patient is recovering well.

Wide Variation in Orthopaedic Access Among Medicaid Patients

OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Christopher Dy, MD, MPH, co-author of a recently published JBJS study.

It is no secret that patients with Medicaid (both adults and children) have difficulty making appointments for both elective and trauma-related orthopaedic care. They also travel further for care compared to privately insured patients. Conversely, Medicaid reimbursement rates for orthopaedic surgeries are substantially lower than those from Medicare and commercial insurers. Patients with Medicaid also tend to be more socially complex and have higher no-show rates for clinic appointments and surgery.

Consequently, as recently as 2011, only 40% of US orthopaedic surgeons were accepting new patients with Medicaid. This “bottleneck” effect may only get worse as reimbursement plans shift towards “pay-for-performance” and value-based payment, prompting surgeons and hospitals to become increasingly concerned about optimizing patient selection.

In a 2012 JBJS study, my colleague Ryan Calfee and co-authors demonstrated that patients with Medicaid were traveling to our institution (Washington University/Barnes Jewish Hospital in St. Louis) not only for complex cases, but also for simple and moderate-complexity hand surgery issues. These patients were bypassing hand surgeons closer to home partly because the local hand surgeons did not accept Medicaid.

With those findings in mind, we decided to more closely examine Medicaid care delivery in our region. Ideally, the insurance mix of the area surrounding a hospital should match the payer mix of the hospital. Most of us who currently work or have trained in large academic centers know that this is often not the case. Anecdotally, there are hospitals in every region that “cherry pick” the best-insured patients and transfer out the financially less desirable cases to a nearby teaching hospital. In our paper, published in the August 21, 2019 issue of JBJS, the concept of “Medicaid share ratio” is intended to reflect whether the hospital payer mix matches the insurance mix of the community. A value of 1 indicates a perfect balance.

We examined the Medicaid share ratios of the 22 hospitals in our region to see if the hospitals were “pulling their weight.” The Medicaid share ratios for elective orthopaedic care such as total joint arthroplasty ranged from 0.05 to 4.73, demonstrating massive imbalances on both ends of the spectrum. We also found very high variability in the delivery of elective orthopaedic care (coefficient of variation = 93, where values >60 are considered “very high”) and moderate variability in trauma care (coefficient of variation = 34).

Our findings were sobering, but not unexpected. The fact that some hospitals bear the brunt of care for the underinsured and uninsured is not new, and the federal government currently includes Disproportionate Share Hospital (DSH) payments to offset these losses. However, DSH payments are scheduled to decrease substantially in coming years as part of the original intent of the Affordable Care Act. If the continuing (and possibly worsening) burden of undercompensated care becomes financially suffocating to teaching and safety-net hospitals, they may seek to curb those losses in ways that could further limit access to underinsured patients and/or drive costs up for patients with other types of insurance.

At the surgeon level, we should address surgeon hesitation to accept Medicaid patients through engagement with specialty societies and policy reform. Our research team is currently working to learn more about what surgeons and patients think are potential solutions for these disparities in our region. As surgeons and researchers, we must work toward a more complete understanding of what drives these disparities in orthopaedic care. Otherwise, it will be impossible to figure out how to fix them.

Christopher Dy, MD, MPH is a hand and peripheral nerve surgeon, an assistant professor at Washington University Orthopaedics, and a member of the JBJS Social Media Advisory Board.

Morbidly Obese Patients Should Lose ≥20 Pounds Prior to TKA

The obesity epidemic continues throughout much of the developed world. Among the morbidly obese (BMI ≥40 kg/m2), we have a group of patients in whom arthritis is very likely to develop due to excessive loading of articular cartilage, chronic inflammation, and alignment problems. At the same time, many arthroplasty surgeons are wary of treating morbidly obese patients with surgery because of the increased perioperative risks. Although many of these patients still benefit greatly from joint replacement, in today’s “value-based care” environment, some institutions have implemented BMI cutoff thresholds for performing knee or hip arthroplasty. Others have set weight-loss requirements before they will schedule lower-extremity arthroplasty for morbidly obese patients. One still-unanswered question along these lines is: how much weight does a morbidly obese patient need to lose preoperatively in order to improve the outcome after a knee replacement?

Keeney et al. address that question in the August 21, 2019 issue of The Journal. In a retrospective cohort study, the authors evaluated outcomes among 203 morbidly obese patients who underwent a total knee arthroplasty (TKA). They found that a loss of 20 pounds preoperatively was associated with a shorter length of stay and a lower chance of being discharged to a rehab or skilled nursing facility rather than home. However, a 20-pound weight loss had no impact on surgical time or functional outcomes, as measured with the PROMIS-10 physical component score. Of note, only 14% of the evaluated patients lost at least 20 pounds preoperatively (highlighting the difficulty of losing weight in general and among this patient population in particular). There were no benefits of any kind in patients who lost only 5 or 10 pounds preoperatively.

While this study’s sample size is small, the findings provide evidence surgeons can use to encourage (or insist upon) larger amounts of weight loss before arthroplasty procedures in morbidly obese patients. In this study, the patients who lost at least 20 pounds remained morbidly or severely obese, and all the patients eventually regained most or all of the weight they lost. Still, the conclusion that at least 20 pounds of weight loss is beneficial for morbidly obese patients prior to a TKA remains sound. Because of the magnitude of this public health issue, we need more high-quality outcomes research (preferably using more knee-specific functional measures) on preoperative management of morbidly obese patients who are considering lower-extremity arthroplasty.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

How Many X-Rays Does It Take to Treat a Distal Radial Fracture?

We orthopaedists obtain radiographs for many reasons—to diagnose an unknown problem, to determine the progress of healing, and occasionally because we follow X-ray “dogma” acquired over time. That last reason prompted van Gerven et al. to undertake a multicenter, prospective, randomized controlled trial, the findings of which appear in the August 7, 2019 issue of The Journal.

The authors set out to evaluate the clinical utility of radiographs taken after a distal radial fracture in >300 patients. Some of those fractures were treated nonoperatively, while others underwent operative fixation. Surgeons of the patients randomized to the “usual-care” pathway were instructed to obtain radiographs at 1, 2, 6, and 12 weeks following the injury/surgery. Surgeons of patients in the “reduced-imaging” arm did not obtain radiographs beyond 2 weeks after the injury/surgery unless there was a specific clinical reason for doing so.

The authors found no significant differences between groups in any of the 6 patient-reported outcomes measured in the study, including the DASH score. Furthermore, the complication rates were almost identical between the usual-care (11.4%) and reduced-imaging (11.3%) groups. Not surprisingly, patients in the reduced-imaging group had fewer radiographs obtained (median 3 vs 4) and were exposed to a lower overall dose of ionizing radiation than those in the usual-care group.

Probably because the study was conducted in the Netherlands, it did not address the widespread practice of “defensive medicine” in the US—the unnecessary overuse of medical tests and procedures to reduce the risk of a malpractice claim. While that may limit the external validity of these findings among orthopaedists in the United States, this relatively simple yet well-designed study should remind us that it is important to have a definite clinical purpose when ordering a test of any type. A picture may be worth a thousand words, but sometimes it takes only 2 pictures to tell the full story of a healing distal radial fracture.

Chad A. Krueger, MD
JBJS Deputy Editor for Social Media

The Softer Side of Better Patient Outcomes

It goes almost without saying that a patient’s return to work after an orthopaedic injury or musculoskeletal disorder would correlate with the severity of the condition. But what about the connection between return to work and a more “touchy-feely” parameter, such as the patient-surgeon relationship?

Dubert et al. conducted a longitudinal observational study of 219 patient who were 18 to 65 years of age and had undergone operations for upper-limb injuries or musculoskeletal disorders. In the August 7, 2019 issue of JBJS, they report that a positive relationship between patient and surgeon hastened return to work and reduced total time off from work.

At the time of enrollment (a mean of 149 days after surgery), the authors assessed the patient-surgeon relationship with a validated, 11-item questionnaire called Q-PASREL, and they collected patients’ functional and quality-of-life scores at the same time. The authors then tracked which patients had returned to work 6 months later, and they calculated how many workdays those who did return had missed.

The Q-PASREL questionnaire explores surgeon support provided to the patient, the patience of the surgeon, the surgeon’s appraisal of when the patient can return to work, the cooperation of the surgeon regarding administrative issues, the empathy perceived by the patient, and the surgeon’s use of appropriate vocabulary.

Here is a summary of the findings:

  • At 6 months after enrollment, 74% of patients who had returned to work had given their surgeon a high or medium-high Q-PASREL score. By contrast, 64% of the patients who had not returned to work had given their surgeon a low or medium-low Q-PASREL score.
  • The odds of returning to work were 56% higher among patients who gave surgeons the highest Q-PASREL scores compared with those who gave surgeons the lowest scores.
  • The “body structure” subscore on one of the functional measurements and the Q-PASREL quartile were the only two independent predictors of total time off from work among patients who had returned to work.

After asserting that their study “confirms that surgeons’ relationships with their patients can influence the patients’ satisfaction and outcomes,” Dubert et al. go on to suggest that the findings should prompt surgeons to “work on empathy, time spent with their patients, and communication.” While they rightly claim that such improvements would entail “little financial investment and no side effects,” perhaps the authors, who practice in France, underestimate the effort that goes into changing behavior—and into addressing the time constraints imposed by the US health care system?

Polytrauma Patients Face Cancer Risk from Imaging Radiation

Orthopaedic surgeons work with radiation in some capacity almost every day. We would struggle to provide quality patient care if it were not for the many benefits that radiographic images provide us. But the more we are exposed to something, the less we tend to think about it. For example, how often do we discuss the risks of radiation exposure with our patients—especially those who are exposed to a large amount of it after an acute traumatic injury?

The article by Howard et al. in the August 7, 2019  issue of JBJS strongly suggests that polytrauma patients need to better understand the risks associated with radiation exposure as they progress through treatment of their injuries. The authors evaluated the cumulative 12-month postinjury radiation exposure received by almost 2,400 trauma patients who had an Injury Severity Score of 16+ upon admission. Those patients received a median radiation dose (not counting fluoroscopy) of 18.46 mSv, and their mean radiation exposure was 30.45 mSv. These median-versus-mean data indicate that a small subset of patients received substantially more radiation than others, and in fact, 4.8% of the cohort was exposed to ≥100 mSv of radiation. To put these amounts in context, the average human in the UK (where this study was performed) is exposed to about 2 mSv of background radiation per year, and there is good evidence suggesting that carcinogenesis risk increases with acute radiation doses exceeding 50 mSv.

Based on mathematical models (actual occurrences of cancer were not tracked), the authors conclude that for these patients, the median risk of fatal carcinogenesis as a result of medical radiation following injury was 3.4%. In other terms, 85 of these patients would be expected to develop cancer as a result of medical imaging—which struck me as a startling estimate.

So what are we to do? In a Commentary accompanying this study, David A. Rubin, MD, FACR offers some practical suggestions for reducing unnecessary radiation exposure. I personally feel that because the radiation associated with CT scans and radiographs can be, quite literally, life-saving for patients who have sustained traumatic injuries, increasing the chance that patients develop cancer later in life in order to save their life now is a good risk-benefit proposition. But the findings from this study should make us think twice about which imaging tests we order, and they should encourage us to help patients better understand the risks involved.

Chad A. Krueger, MD
JBJS Deputy Editor for Social Media