Isoelastic Monoblock vs Modular Press-Fit Cup
As the volume of total hip arthroplasty (THA) cases continues to rise, so too will the need for revision surgery. Revision THA can be complicated by insufficient bone stock on either the femoral or acetabular side, and researchers are gaining further insight into bone loss potentially related to implant design, such as loss that may occur through stress-shielding from press-fit implants.
In a randomized controlled trial recently reported in JBJS, Brodt et al. evaluated reduction in bone mineral density (BMD), primarily periacetabular BMD, as measured in 2 groups: patients who received a press-fit isoelastic monoblock cup (24 patients analyzed) and those who received a modular titanium press-fit cup (23 patients analyzed). At question was whether an isoelastic monoblock cup, with an elastic modulus similar to that of bone, would lead to less stress-shielding and thus less bone loss compared with a conventional modular titanium cup.
Periprosthetic BMD was assessed at 1 week postoperatively (baseline) and at 4 years postoperatively using dual x-ray absorptiometry (DXA). The authors evaluated 4 regions of interest (ROIs) around the acetabular component and 7 ROIs around the femoral component based on regions previously described in the literature for assessing periprosthetic bone loss.
Baseline patient characteristics, operative time, and improvement in clinical outcome scores did not differ between the groups. A decrease in overall periacetabular BMD was found in both groups, but the difference between the groups was not significant.
However, the researchers found a significant difference between the groups in BMD changes in certain periprosthetic regions. On the acetabular side, the group with the modular titanium cup had a 15.9% decrease in BMD in zone 2 (the superior pole of the acetabulum) compared with a decrease of 4.9% in the group with the isoelastic monoblock cup. And on the femoral side, the group with the modular titanium cup had a 15.4% decrease in BMD in zone 1 (along the greater trochanter) compared with a loss of 7% in the group with the isoelastic monoblock cup. None of the other regions differed significantly between the groups.
Despite the relatively short follow-up and small (but adequately powered) numbers, these results are worthy of our consideration. I agree with the authors that longer follow-up is needed before conclusions can be drawn. As implant design can impact component longevity, it is critical that we evaluate differences to better understand the long-term implications.
Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media
JBJS Webinar June 28–Femoral Neck Fractures: The THA vs Hemi Toss-Up
Consulting with their patients, orthopaedic surgeons make many decisions each day by weighing the best evidence available. One frequent—and controversial—decision is how best to treat displaced femoral neck fractures, a common injury among elderly patients.
Often this choice comes down to hemiarthroplasty (HA) or total hip arthroplasty (THA). The preponderance of evidence suggests that outcomes from both procedures are nearly equivalent. On Monday, June 28, 2021 at 8 pm EDT, JBJS will host a complimentary 1-hour webinar delving into the most recent findings about this dilemma.
Mohit Bhandari, MD, PhD will present findings from a 2020 Level-I meta-analysis of 16 randomized controlled trials. Functional outcomes and 5-year rates of revision and dislocation were similar between groups. THA eked out a small advantage in health-related quality of life, and HA yielded minor reductions in operative time.
Bheeshma Ravi, MD, PhD will discuss data comparing the 2 procedures in terms of complications and costs. Based on findings from this propensity score-matched analysis, the nod goes to THA, with lower 1-year rates of revision surgery and lower health-care costs.
Moderated by Bassam A. Masri, MD, FRCSC, the webinar will feature expert commentaries on these “neck-and-neck” findings. Pierre Guy, MD will comment on Dr. Bhandari’s paper, and Kelly Lefaivre, MD will weigh in on Dr. Ravi’s paper.
The webinar will conclude with a 15-minute live Q&A session during which attendees can ask questions of all the panelists.
Seats are limited–so Register Today!
CME credit will be available for surgeons and PAs attending this event live for a minimum of 50 minutes. Directions to claim your CME credit will be sent out within 48 hours of the broadcast.
Journal Club Resident Spotlight: Jacob Wilson
JBJS is pleased to highlight the orthopaedic residents who help implement the Robert Bucholz Resident Journal Club Grants at their institutions. The grant program promotes career-long skills in evaluating the orthopaedic literature. Click here for more information.
Name: Jacob Wilson, MD
Affiliation: Emory University School of Medicine, Atlanta
What was the topic of the most “dynamic” journal club meeting you have had so far this year?
We recently held an arthroplasty-themed journal club that was well received. We discussed 4 different papers, but I found the discussion on 2 to be particularly interesting. This included a study on long-term outcomes of cemented versus cementless total knee arthroplasty[1] and a randomized controlled trial on the use of virtual physical therapy visits after total knee arthroplasty.[2] These studies were well-designed and stimulated lively discussion.
- Kim, Y.H., J.W. Park, and Y.S. Jang, The 22 to 25-Year Survival of Cemented and Cementless Total Knee Arthroplasty in Young Patients. J Arthroplasty, 2021. 36(2): p. 566-572.
- Prvu Bettger, J., et al., Effects of Virtual Exercise Rehabilitation In-Home Therapy Compared with Traditional Care After Total Knee Arthroplasty: VERITAS, a Randomized Controlled Trial. J Bone Joint Surg Am, 2020. 102(2): p. 101-109.
What are the top 3 characteristics of an engaging, enlightening journal club presentation?
In my experience, journal club can be one of the better educational opportunities as a resident. There are a few things that are critical to making this the case. 1) Obviously, everyone needs to read the articles that are being discussed. This goes a long way in making the journal club interactive and constructive. 2) Attendance, particularly by faculty, is critical. I have found that when faculty from a variety of subspecialties attend, good discussions are generated. 3) Proper article selection. While landmark papers are important and should be reviewed by all residents, for the purposes of journal club, recent, clinically applicable articles that have the potential to change practice seem to be more interesting to those in attendance.
How has the COVID-19 pandemic affected your journal-club activities?
Like essentially all aspects of our lives, COVID-19 significantly changed our journal-club activities over the past year. Given national, regional, and institutional guidelines, our program moved all educational activities, including journal club, to virtual formats. While different than what we were previously accustomed to, this has made attendance easier for some faculty. That said, we are looking forward to a return to some degree of academic normalcy when we are able.
Aside from orthopaedic content, what have you been reading lately?
I’ve admittedly slacked on reading outside of orthopedics during residency. However, I have always been a fan of narrative nonfiction and am currently reading Dead Wake by Erik Larson.
How has free access to JBJS Clinical Classroom benefited you and your journal club?
I have found JBJS Clinical Classroom to be a good resource. As I prepare for Part I of my board exam, Clinical Classroom has been an easy and nice way to review concepts quickly. The app has made it easy to quickly do a few questions between cases. The content in Clinical Classroom is linked to primary literature, and this has led to some articles being selected for discussion at journal club.
Caution Appropriate as We Investigate New Approaches to Pain Management
The dangers of chronic opioid use have rightly been at the forefront of orthopaedic practice considerations in recent years. The widespread use of regional anesthesia and periarticular-injection cocktails, targeted NSAID utilization, and strict limitations on opioid use have become standard approaches for postoperative pain management.
With the availability of cannabinoids in numerous state jurisdictions, attention has now turned to the potential of these compounds to enhance patient comfort in the postoperative period. However, as we contemplate their use, it’s imperative that we also evaluate the impact of these compounds on clinically important outcomes such as bone-healing and fusion. The track record of nicotine, NSAIDs, and other compounds in terms of the impact on bone-healing is enough to suggest caution.
In the June 2, 2021 issue of JBJS, Yun et al. provide new insight into this topic. Specifically, they evaluated the impact of cannabinoid receptor agonist WIN55 on osteogenic differentiation in vitro and bone regeneration and spinal fusion in a preclinical rat model.
They found that WIN55 had no adverse impact on osteogenic differentiation of primary bone marrow stem cells in vitro. As noted by the authors, “mRNA expression levels of Runx2 and Alp were similar among cells treated with vehicle alone and WIN55. Likewise, exposure to WIN55 did not inhibit ALP [Alkaline phosphatase] activity or bone matrix mineralization.”
In addition, no adverse impact of WIN55 on spinal fusion or bone regeneration was found. Forty-five rats (15 per group) underwent L4-L5 posterolateral spinal fusion with bilateral placement of collagen scaffolds soaked with rhBMP-2. The rats were treated with vehicle alone or 0.5 or 2.5 mg/kg WIN55 by way of daily intraperitoneal injections for 5 days. Radiography, manual palpation-based fusion scoring, microCT, and histology were used for assessment. No significant differences among the groups in the mean fusion score, fusion rate, and new bone volume were demonstrated.
These findings are intriguing, and such research helps set the stage for carefully designed in vivo research projects, eventually moving toward randomized controlled trials, before recommending widespread use of cannabinoids for post-surgical pain management.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
JBJS Author Insights: Dr. Ran Schwarzkopf
Co-author Ran Schwarzkopf, MD, MSc discusses the new JBJS study “Tranexamic Acid Is Safe in Patients with a History of Coronary Artery Disease Undergoing Total Joint Arthroplasty.” Watch the video below.
Read the full report here.
Multiligamentous Knee Injury May Not Be Synonymous with Knee Dislocation
Terminology is important in orthopaedics. When teaching, for instance, we stress the need for trainees to be able to articulate what a radiograph is showing using descriptive terms and classification systems.
Over the years, “multiligamentous knee injury” (MLKI) and “knee dislocation” have increasingly been used interchangeably within the orthopaedic vernacular, in part because of the high energy required to sustain such injuries, but also because of the potentially devastating complications that can be associated with both.
Kahan et al. sought to better characterize these injuries and their associated complications in a study now reported JBJS. They retrospectively evaluated cases treated at their Level-I trauma center between 2001 and 2020.
A total of 123 patients with MLKI were included in the analysis: 45 patients with and 78 patients without a documented knee dislocation. MLKI was defined as disruption of at least 2 of the following: the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. Cruciate ligament injuries and isolated injuries of the superficial medial collateral ligament were not included unless there was disruption of the posteromedial corner, semimembranosus, or medial patellofemoral ligament, indicating a more extensive medial-sided injury.
The investigators found that medial-sided injuries were more common in the dislocation group (53% vs 30%; p = 0.009), and the dislocation group had higher rates of peroneal nerve injury (38% vs 14%; p = 0.004) and vascular injury (18% vs 4%; p = 0.018). Of the 11 total patients with a vascular injury, 8 (73%) were in the dislocation group; 10 of the 11 underwent a vascular surgical procedure.
Not all cases of MLKI are a result of a knee dislocation, and in this adequately powered study, there were differences in the injury pattern and associated injuries between those with and without true dislocation. It is important to note that, although higher rates of neurovascular injury were seen in the dislocation group, such events also occurred in the group without dislocation, so a high index of suspicion must be maintained with these complex injuries. As the authors suggest, it may be better to consider cases of knee dislocation a subset of MLKI with the potential for increased neurovascular compromise.
Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media
Is It Time to Use Ultrasound in Diagnosing Zone-II Flexor Tendon Injuries?
OrthoBuzz occasionally receives posts from guest bloggers. In response to a recent article in Ultrasound in Medicine and Biology by Bekhet et al., this commentary comes from Christopher Dy, MD, MPH.
In their study from Cairo, Egypt, Bekhet et al. report their experience using ultrasound (US) to examine tendon integrity in the setting of suspected flexor tendon injury. A single musculoskeletal radiologist performed diagnostic US in 35 patients with trauma to the ventral surface of the hand or wrist; a total of 50 tendons were evaluated, with zone-II injuries being the most common.
US correctly identified all complete tendon disruptions, with no false positive or false negative results. US identified partial tendon injuries with 98% accuracy, with 1 false positive result and no false negatives. In comparison, clinical examination alone had a diagnostic accuracy of 88%. The diagnostic performance of US in this study is impressive, and suggests that US may have a role in the diagnostic workup of patients with suspected flexor tendon injury.
While many surgeons still rely on physical examination, it is clear that clinical assessment alone is imperfect. An accurate, objective diagnostic test is desirable for determining the need for (and extent of) surgical treatment as well as in counseling patients. MRI has been suggested to fill this role, but it can be expensive and time-consuming. US is a natural alternative, but its usage in most practice settings (including North America) has been limited because of its operator-dependent nature. That is a key acknowledgment made by the authors of this study, which limits the generalizability and impact of their findings. As only 1 highly specialized radiologist performed the US examinations in the study, it is unclear whether US performed by a less-experienced sonographer would provide the level of detail needed to directly affect clinical management.
Further validation studies (both within the authors’ institution as well as in other centers) would provide important information to determine the utility of US in accurately diagnosing the location and extent of flexor tendon injuries.
In my practice, if there is doubt regarding the integrity of a flexor tendon, I have used US performed by a musculoskeletal (MSK) radiologist or a US-trained physiatrist to provide diagnostic clarity. Admittedly, if the US results do not match my clinical impression, I will either order an MRI or discuss surgical exploration with the patient. This bias in my decision-making process clearly demonstrates my belief that further work is needed to show that US can be used accurately and reliably. While the findings of Bekhet et al. are intriguing, the single-sonographer limitation leads me to question the external validity of their findings. Because of this, the findings of this study are not practice-changing. But I hope to be proven wrong!
Christopher Dy, MD, MPH is a hand and wrist surgeon, an assistant professor of orthopaedic surgery at Washington University School of Medicine in St. Louis, and a member of the JBJS Social Media Advisory Board.
Large Lytic Defects Produce Spinal Kinematic Instability
With the increasing effectiveness of immunotherapy and chemotherapy, patients with metastatic disease are surviving longer in much higher numbers. For many primary tumors (lung, breast, thyroid), a common site of metastases is the spine, giving rise to concomitant concerns regarding spine stability and the risk of neurologic compromise.
In the May 19, 2021 issue of JBJS, Alkalay et al. report the results of an in vitro study in which they simulated osteolytic defects in 3-level thoracic and lumbar segments of cadaveric spines. The simulations involved 2 patterns of lytic defects previously reported to be associated with increased risk of pathologic vertebral fracture: anterior-column compromise (40% of the vertebral body) and anterior plus middle-column compromise (extension of the model to include the ipsilateral pedicle and facet joint). The spinal segments were kinematically assessed in axial compression and axial compression with a flexion or extension moment, with testing before and after lesion simulation.
The authors concluded that “critical spinal lytic defects result in kinematic abnormalities and lower the compressive strength of the spine.” With greater lytic involvement, significantly higher translational motion along all 3 anatomic axes, and higher torsional and lateral-bending range of motion under axial compression with both flexion and extension moments were demonstrated.
The precision of the model in this cadaveric study was excellent. And the clinical implications of the findings are real: increasing lytic involvement of the vertebral body along with the pedicles could indicate impending instability, with the potential for neurologic injury. These data will be useful for surgeons and patients when formulating decisions regarding the need for intervention with fixation to limit flexion/extension forces in order to reduce pain and neurologic involvement. Future clinical data on the impact of these decisions in terms of pain and functional outcomes will be very valuable as we seek to optimize treatment of our patients with spinal metastatic disease.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
Loss of Supination Force with Partial Distal Biceps Avulsion
In the May 5, 2021 issue of JBJS, Tomizuka et al. report the results of mechanical testing in which they quantified the loss of supination and flexion strength after a series of surgical releases designed to simulate traumatic avulsions of the short and long head of the distal biceps tendon.
Reflecting on the clinical implications of their study, the authors note:
Partial tears of the distal biceps tendon can cause substantial disability, yet the mechanical effect of such ruptures is not fully understood. This study showed that a simulated complete short-head tear significantly decreased (p ≤ 0.043) the supination moment arm by 24% in pronation and 10% in neutral.
A mechanical case can be made for early repair of a partial distal biceps tendon tear when the rupture is ≥75% of the distal insertion site.”
Click here for the full JBJS report.
A JBJS Clinical Summary on distal biceps tendon rupture can be found here.
Functional Outcomes of Patients with Schizophrenia After Hip Fracture Surgery
Thirty-eight patients with schizophrenia were compared with 170 geriatric patients without schizophrenia who underwent a surgical procedure for a hip fracture.
Read the full article here.
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