Subacromial Balloon May Benefit Irreparable Cuff Tears
The surgical options for treating irreparable tears of the supraspinatus—cuff reconstruction, tendon transfers, and shoulder replacement—are limited and complicated. But biomechanical results from a cadaveric study of 14 shoulders by Lobao et al., published in the June 5, 2019 issue of JBJS, suggest that a biodegradable balloon spacer inserted subacromially could effectively treat such insufficiencies, possibly postponing the need for more aggressive procedures.
Using an irreparable supraspinatus tear model and sophisticated instruments, the authors determined that, at postoperative time 0, the saline-inflated balloon:
- Restored intact-state glenohumeral contact pressures at most abduction angles
- Moved the humeral head inferiorly by a mean of 6.2 mm at 0° of abduction and 3.0 mm at 60°
- Increased deltoid load by 8.2% at 0° and by 11.1% at 60°.
The balloon, however, did not restore glenohumeral contact area to that of an intact shoulder.
Although the authors cite a previous clinical case series using this approach,1 they are quick to point out that “it is not possible to correlate our findings with clinical scenarios.” Nevertheless, they say that the biomechanical data obtained from this cadaveric study “suggest that the balloon may be of benefit clinically, at least in the immediate postoperative setting.”
Reference
- Deranlot J, Herisson O, Nourissat G, Zbili D, Werthel JD, Vigan M, Bruchou F. Arthroscopic subacromial spacer implantation in patients with massive irreparable rotator cuff tears: clinical and radiographic results of 39 retrospectives cases. Arthroscopy. 2017 Sep;33(9):1639-44. Epub 2017 Jun 8
Diagnosing Infection in “Dry” Prosthetic Joints
Despite a bevy of research and intense clinical focus, definitively diagnosing periprosthetic joint infections (PJIs) remains a major challenge in many patients. There is no single test that can confirm a PJI diagnosis with absolute accuracy, and surgeons often encounter clinical factors that make the diagnostic challenge even more complex. One such scenario is when a surgeon cannot aspirate enough fluid for culture from the affected joint of a patient who may have a PJI. In such situations, important microbiological data that would come from culturing synovial fluid are unavailable, leaving treating surgeons information-poor.
In the June 5, 2019 issue of The Journal, Li et al. provide surgeons with data about a controversial solution to this so-called “dry-tap” problem. The lead author performed aspirations on nearly 300 joints that were suspicious for periprosthetic infection. Eighty-two of those aspirations (29%) yielded ≤1.0 mL of synovial fluid. In those “dry-tap” cases, 10 mL of saline solution was injected into the joint, which was then reaspirated.
When comparing cultures from the aspirates that were the result of a saline lavage to those in which no lavage was performed, the authors found overlapping 95% confidence intervals in sensitivity, specificity, positive predictive value (PPV), and negative predictive value. However, the specificity (0.991 vs 0.857) and PPV (0.987 vs 0.889) were higher in the nonlavage cohort, even if those differences did not reach statistical significance. In addition, no significant differences were found between the groups in terms of relative frequencies of specific pathogen types.
Although the authors conclude that this lavage-and-reaspiration technique “is not necessarily inappropriate,” it is important to note that no post-hoc power analysis was performed, and therefore type II error needs to be considered because the study was probably underpowered. In addition, the International Consensus Meeting (ICM) recommends against lavaging a “dry” joint to obtain fluid for culture, largely because the injected saline will dilute results if a leukocyte esterase strip test or cell count is subsequently performed as part of the PJI-diagnosis process. Still, the authors point out that the data supporting the ICM’s recommendations against this practice are relatively weak, and the specificity and sensitivity data from this study are quite satisfactory.
So does this give us another option for determining whether a periprosthetic joint infection is present in patients from whom little or no synovial fluid can be obtained? Maybe. But this technique requires further investigation before it becomes widely implemented in practice. Without validation, it risks becoming just one more variable that could reinforce our own confirmation biases in these challenging cases. With further validation, however, it could allow pre-revision collection of valuable and accurate culture information from “dry” joints.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
Marian Frauenthal Sloane, MD: Ahead of Her Time
In 2016, only 6.5% of practicing orthopaedic surgeons in the US were women. By contrast, 49% of all medical students in the US are women. That apparent discrepancy has sparked concern, conversations, and action in the orthopaedic community.
The current gender imbalance in orthopaedics would be even more stark were it not for two trailblazing women who lived during the early part of the 20th century. One of them, Ruth Jackson, MD, is the well-known namesake of today’s professional society of female orthopaedic surgeons. The other, New York City orthopaedist Marian Frauenthal Sloane, MD, has endured relative obscurity, until now.
The “What’s Important” essay by Hooper at al. in the June 5, 2019 issue of The Journal of Bone & Joint Surgery profiles Dr. Frauenthal Sloane’s short but influential career as orthopaedic surgeon, researcher, author (she coauthored 2 JBJS articles in the 1930s), and teacher. Despite the long way we still have to go to achieve gender diversity in orthopaedics, the authors of this fascinating sketch conclude by saying that “without [Dr. Frauenthal Sloane’s] brief but profound influence, women orthopaedists would probably be in a very different place today.”
Read related OrthoBuzz post about diversity in orthopaedic surgery.
New Minute-Commentary Video
See what JBJS Deputy Editor for Social Media Chad Krueger, MD thinks about the just-published Level-I trial comparing nonoperative treatment to volar locking plate fixation among 140 elderly patients with dorsally displaced distal radial fractures.
Pelvic Fracture Classification Will Benefit Elderly Patients
The orthopaedic community began to move away from individual fracture classifications in the mid-1980s. The basis for that shift was the need for wider recognition that fractures represent a “continuous variable,” with infinite varieties of orientations and combinations of fracture lines. Trying to fit fractures into a narrow classification system can lead to confusion and misinformation. Furthermore, surgeons often disagree when determining a fracture’s classification and, therefore, which treatment is best.
To move away from individual classification systems, orthopaedic journals have generally moved toward the compendium of fracture classifications approved by the OTA and AO. Still, there are times when a new fracture classification seems appropriate, and in the June 5, 2019 issue of The Journal, Pieroh et al. have provided us with an example that classifies fragility fractures of the pelvis (FFP). The 4-group FFP classification is based on fracture morphology with different degrees of instability and includes treatment recommendations.
The authors collected the CT scans of 60 patients from 6 different hospitals who were ≥60 years old and had sustained a pelvic fracture from low-energy trauma. These CT scans were shown to 6 experienced surgeons, 6 inexperienced surgeons, and 1 surgeon who had direct experience/training with the FFP system. Each surgeon was asked to classify the pelvic fractures according to the FFP classification. Inter- and intra-rater reliabilities for the fracture classifications were calculated from these readings, and the overall inter-rater Kappa coefficient was found to be 0.53, while the overall intra-rater Kappa coefficient was 0.46 (Kappa coefficients of 0.61 to 0.41 constitute “moderate” reliability). In terms of percent agreement, there was greater agreement between surgeons when it came to classifying FFP Group 1 fractures than for FFP Group 2 and 3 fractures. This is noteworthy because Group 3 fractures are thought to require surgical treatment, while primary treatment for Group 2 fractures is usually nonoperative.
Pelvic fractures that are associated with low bone density and low-energy trauma are becoming increasingly frequent as our population continues to skew older. Having a validated, relatively straightforward classification system like the FFP to assist us in managing these patients will be of great assistance. The sound methodology used to develop the FFP classification system and its decent reliability, face validity, and construct and criterion validity can assure all of us about the usefulness of the FFP classification as the basis for future clinical investigations and to advance the care of these patients.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
FDA Approves Rapid Alpha-Defensin Test for PJI
The US FDA has approved the Synovasure Alpha Defensin Lateral Flow Test Kit for helping detect periprosthetic joint infection (PJI) in the synovial fluid of patients being evaluated for revision joint replacement.
Alpha defensins are proteins released by neutrophils in early response to infection. OrthoBuzz previously summarized a 2018 JBJS study that found this rapid alpha defensin test to have 96.9% overall accuracy.
In the FDA news release about the approval, Tim Stenzel, MD, director of the FDA’s Office of In Vitro Diagnostics and Radiological Health, said the test provides health care professionals with additional information that “could potentially reduce patient risk by avoiding unnecessary revision operations for replacement joints.”
In a Commentary on the 2018 JBJS study, Garth Ehrlich, PhD and Michael Palmer, MD said the device is a “substantive advance,” but not “a panacea.” For one thing, metallosis would still need to be ruled out with MRI, because that noninfectious etiology triggers a false-positive result with this rapid test. Synovasure is also likely to miss detection of slow-growing, chronic bacterial pathogens such as Proprionibacterium acnes, the commentators said.
The Synovasure test kit received approval through the FDA’s de novo premarket pathway, which is reserved for “low- to moderate-risk devices of a new type,” according to the agency.
Electrocautery Damages Metal Hip Implants in 2 Ways
In the setting of revision total hip arthroplasty (THA), the use of electrocautery—and contact between the thermal device and retained components—cannot always be avoided. In the May 15, 2019 issue of The Journal of Bone & Joint Surgery, Sonntag et al. perform two implant-retrieval analyses and a separate in vitro investigation to determine what kinds of damage take place when electrocautery energy meets titanium femoral stems.
The components for retrieval analyses were removed from patients who experienced a fracture of the femoral stem or femoral neck after revision THA. The authors found superficial discoloration and melting marks on the retrieved components, and elemental analysis indicated that material had been transferred from the electrocautery tip. During in vitro testing of 6 titanium alloy femoral stems, the authors found that electrocautery surface damage reduced load-to-failure by up to 47% when compared to undamaged femoral neck specimens. Microscopic analysis revealed notable changes in metal microstructure in electrocautery-exposed components, whereby certain zones exhibited higher strength than others, which, the authors speculate, might result in lower overall fatigue resistance.
Both the retrieval and in vitro analyses showed that electrocautery damage to femoral implants, particularly in the anterolateral region at the base of the neck, reduced implant fatigue resistance. However, the authors say their results need to “be carefully interpreted,” because they are based on only 2 retrievals and a limited number of test specimens. Nevertheless, they conclude that “electrocautery device contact [with femoral implants] should be avoided and the use of conventional scalpels is recommended, where reasonable.”
NYT Cites Hype of Stem-Cell Treatments for Joint Problems
An active, 71-year old man who declined joint replacement in favor of stem-cell treatment is quoted in a recent New York Times article as saying, “They’re really quick to try to give you fake joints and make a bunch of money off you.” But the NYT article goes on to suggest that making money may be the main objective of some of the many hundreds of clinics that have sprung up around the US to offer cell-based injections to people with aging or damaged joints who want relief without surgery.
The article points out that the FDA has “taken an industry-friendly approach toward companies using unproven cell cocktails” and that the scant scientific evidence about these treatments, which include injections of platelet-rich plasma, is inconclusive.
For OrthoBuzz readers who want to dive more deeply into the scientific underpinnings (or lack thereof) related to cell therapies for joint problems, please peruse the following JBJS and JBJS Reviews articles, which have been made openly available for a limited period of time:
- Intra-articular Cellular Therapy for Osteoarthritis and Focal Cartilage Defects of the Knee
- Nomenclature Inconsistency and Selective Outcome Reporting Hinder Understanding of Stem Cell Therapy for the Knee
- International Expert Consensus on a Cell Therapy Communication Tool: DOSES
- Stem Cell Therapy for Knee Pain–What Exactly Are We Injecting, and Why?
- A Call for Standardization in Cell Therapy Studies
- A Comprehensive Review of Stem-cell Therapy
The main message running through all these articles is this: Effective clinical assessment and safe, optimized use of cell-based therapies demands greater attention to study methods; standards for cell harvesting, processing, and delivery; and standardized reporting of clinical and structural outcomes.
The Economics of Revision THA for Fractures: Sustainable?
At the risk of economic oversimplification, it is difficult to sustainably provide a service when payment for it is less than the cost to perform it. But that is one reality exposed by Hevesi et al. in the May 15, 2019 issue of The Journal. Using National Inpatient Sample and ACS-NSQIP data, the authors compared the average costs and 30-day complication rates for revision total hip arthroplasties (THAs) performed for 3 different indications—fractures, wear/loosening, and instability—at both a local and national level. They found that the average hospitalization costs associated with a revision THA related to a fracture were 33% to 48% higher (p < 0.001) than the cost of revision THAs related to wear or instability.
However, the authors emphasize that all 3 of these indications for revision THA are reimbursed at the same rate based on Medicare Diagnosis-Related Group (DRG) codes. DRGs take into account patient comorbidities to determine reimbursement levels—but they do not adjust payments for THA revision according to indication. Hevesi et al. note that the only DRG reimbursement level that would cover the average cost of a revision THA for a fracture would be one performed on a patient with severe medical comorbidities or a major complication. Not surprisingly, patients who underwent a revision THA to treat a fracture were found to have a higher age and more medical comorbidities than those undergoing a revision for wear or instability.
The authors use this data to make a very compelling case that DRGs for revision THA should be changed so they are indication-specific, taking into account the underlying reason for the revision. They observe that “a DRG scheme that does not distinguish between indications for revision THA sets the stage for disincentivizing the care of fracture patients and incentivizing referrals to other facilities.” Those “other facilities” usually end up being large tertiary-care centers, which the authors claim “perform a higher percentage of the costlier revision THA indications.”
This problem of reimbursement inequality is not unique to revision THAs and requires further investigation in many fields. Unless “the system” addresses these subtle but important differences, tertiary referral centers may be inundated with patients who need procedures that cost more to perform than the institutions receive in reimbursement—an unsustainable scenario.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
Trauma in the Developing World: A Call to Action
Over the past decade and a half, the problem of musculoskeletal trauma has been identified as impacting more individuals in developing countries than HIV, drug-resistant tuberculosis, and other infectious diseases that are commonly recognized as public health crises. The need for access to surgical treatment for patients who sustain traumatic injuries has recently garnered more attention. Yet funding from nongovernmental organizations and other national/international foundations has not reached the levels necessary to appropriately address this important public health issue.
In the May 15, 2019 issue of The Journal, Agarwal-Harding et al. document the issue of patients experiencing delayed access to musculoskeletal trauma care in the sub-Saharan country of Malawi. Thanks to the development of a trauma-care registry serving both rural and urban health centers in Malawi, the authors were able to clarify the factors associated with delayed presentation for care.
Not surprisingly, those factors included distance from treatment centers and sustaining an injury during a weekend. These issues are likely widespread throughout Africa and in many other developing countries, where EMS services are sparse at best and treatment facilities are generally under-resourced. Although an increasing number of people in developing countries are being injured in road/vehicle-related accidents, many of the patients evaluated in this study did not experience high-energy trauma, but were instead injured from falls and during sporting activities. In short, they experienced the types of injuries that are likely to occur to everyday people doing everyday activities anywhere in the world.
The issue of delayed access to care is addressable if we continue to acknowledge the incredible public health burden that musculoskeletal trauma places on individuals and society within the developing world. These injuries not only affect patient quality of life, but they also have large impacts on families and communities due to a loss of income or disability-imposed restrictions on community engagement. Addressing this issue is of great interest to the readers of JBJS, who are volunteering to serve the orthopaedic needs of the developing world in ever-increasing numbers.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
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