Study Supports Routine Patellar Resurfacing during TKA
The July 17, 2019 issue of The Journal features another investigation evaluating patellar resurfacing. Despite much research (see related OrthoBuzz post), this topic remains controversial among many total knee arthroplasty (TKA) surgeons. This study, by Vertullo et al., analyzed data from the Australian Orthopaedic Association National Joint Replacement Registry. The findings suggest that routine resurfacing of the patella reduces the risk of revision surgery for TKA patients.
The authors evaluated more than 136,000 TKA procedures after placing the cases into three groups based on the surgeon’s patellar-resurfacing preference: infrequent (<10% of the time), selective (10% to 90% of the time), or routine (≥90% of the time). All of the cases evaluated utilized minimally stabilized components and cemented or hybrid fixation techniques, and they all were performed by surgeons who completed at least 50 TKAs per year.
The authors found that patients in the infrequent-resurfacing cohort had a nearly 500% increased risk of undergoing subsequent patellar revision during the first 1.5 years after TKA, compared to those in the routine-resurfacing cohort. Even more surprising to me was the finding that patients in the selective-resurfacing cohort had a >300% increased risk of needing a patellar revision within the first 1.5 years, compared to those in the routine-resurfacing cohort. In addition, the risk of all-cause revision was 20% higher in the selective cohort compared to the routine cohort.
What struck me most about this study were the differences between the selective and routine cohorts. One of the arguments against routine resurfacing of the patella is that surgeons should decide intra-operatively, on a patient-by-patient basis, whether the osteochondral health and biomechanics of the native patella warrant resurfacing. The findings of Vertullo et al. seem to call that reasoning into question. Although the results of this study add to the evidence supporting the routine resurfacing of the patella during TKA, I would like to reiterate a proviso from my earlier post on this topic: resurfacing is associated with added costs and an increased risk of potential complications.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
Why US Orthopaedic Residents Overprescribe Opiates
Several authors have described the medical-school experience as “socialization” into the medical field. Medical students often learn the scientific underpinnings simultaneously with the social processes of interviewing/dialoging, examining, and then developing a treatment plan with the patient. One “subspecialty” social process that orthopaedists learn is pain management. While we are certainly encouraged to understand the scientific basis of this important and complex topic, much of the learning comes in the form of mirroring: junior residents do what senior residents instruct them to do, while senior residents follow the direction of attendings. These passed-on habits are culturally ingrained and persistent.
As Young et al. show in the July 17, 2019 issue of The Journal, the pain-management habits learned in training vary greatly from country to country, which is not surprising. Specifically, these authors examined the prescribing of postprocedural opiates by residents in the Netherlands, Haiti, and United States. They found that US residents prescribe significantly more morphine milligram equivalents (MMEs) of opioids at patient discharge than residents from either of the other 2 countries. The authors also showed that residents from the United States were the only group prescribing a significantly greater amount of MMEs to patients younger than 40 years old than to those above the age of 70.
Many pundits pin the phenomenon of opioid overprescribing in the US on the American public’s wish to be free from discomfort, along with the aggressive marketing and advertising of these medications in the United States. While this may be true, I think Young et al. have further identified the major influence that a resident’s training environment may have on prescribing practices. As already mentioned, residents often imitate what they see from more experienced residents and attendings, but sometimes those lessons, especially in pain management, lack a scientific basis.
What is missing from this survey-based study is data on patient satisfaction with postprocedural opiate prescribing. Having been involved in clinical care in Haiti, my impression is that patients there accept the local practice of pain management, constrained as it might be by resource limitations. I suspect the same is true in the United States and the Netherlands. Regardless, these findings demand that emphasis be placed on teaching orthopaedic residents evidence-based pain-management protocols. This will require a concerted effort from teachers and mentors at all levels of our medical-education system. This investigation is an important reminder that developing solutions to the opioid overprescribing problem in the US might begin in residency, where “cultural formation” occurs.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
With or Without Cement, Results with Triathlon TKA Are Same after 2 Years
With the increasing frequency of total knee arthroplasty (TKA) surgeries and the ever-increasing implant options available to orthopaedists for these cases, it is important that we carefully analyze new devices and technologies. We have already seen too many instances in which the enthusiasm for (and use of) a new implant outpaced the evidence for its efficacy and safety, leading to problems for patients, surgeons, and manufacturers alike.
The results of the randomized trial by Nam et al. in the July 3, 2019 issue of The Journal start to tackle this issue. The authors compared operative times, patient outcomes, and radiographic measures between patients who received either a recently introduced cementless or traditionally cemented cruciate-retaining TKA implant of the same design (the Triathlon TKA implant from Stryker). They found no clinically meaningful or statistically significant differences between the two groups in terms of Oxford Knee Score or Knee Society Score at any point during the average 2-year follow-up. In addition, nearly equal percentages of patients in each group reported being “extremely” or “very” satisfied with their functional outcome at 2 years, and radiographically, the researchers found no significant difference between the groups in terms of radiolucency behind the tibial or femoral implants. The one notable between-group difference was operative time, with the cementless cohort having a mean surgical time roughly 11 minutes less than that of the cemented cohort.
These results are encouraging in that they show improved operative efficiency with none of the aseptic loosening that has historically been a concern with cementless knee implants. Still, the authors make it clear that “the burden of proof remains with cementless fixation,” largely because cementless implants cost more than their cemented counterparts. Those higher costs need to be justified by improved outcomes (including implant survivorship), decreased complications, or both in order for cementless implants to displace cemented ones as the “standard of care.”
We are not there yet, but the findings from Nam et al. justify further surveillance of this cementless device. Future high-quality studies incorporating joint registry data and longer patient follow-up will hopefully provide the supporting evidence with which the joint-arthroplasty community can decide whether this relatively new cementless technology should be the implant of choice for certain patient populations.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
Placenta-Derived Cells Give Short-term Boost to Tendon Repair
From journal articles to nightly news segments, it’s hard to avoid the barrage of information related to the use of cell-based therapies for musculoskeletal problems. While these approaches may turn out to be enthusiasm outpacing science (see related OrthoBuzz post, “Stemming the Tide of Stem Cell Hype”), one reason for the excitement is rooted in a very simple fact: it is really hard to get many soft tissues to heal, especially in certain patient populations. Moreover, failure of initial repair usually leads to even more biologically inhospitable repair environments. This clinical challenge has led to the zealous investigation of various cell-based compounds to see which ones might assist native soft-tissue cells with the formidable task of quick healing.
In the July 3, 2019 issue of The Journal, Ma et al. investigate the potential for human placenta-derived cells to augment the healing of chemically induced patellar tendon ruptures in rats. The injected placental cells introduced a transitory inflammatory response that led to increased load to failure at the 2-week mark, compared to biomechanical results in control rat tendons injected with saline solution. However, the addition of placenta-derived cells did not increase tendon load to failure beyond 2 weeks, and at no time point were differences seen between the control and experimental groups in tendon strength, stiffness, collagen organization, or cellularity.
While the positive results of this study were short-lived, they are important nonetheless. The animal model used is well thought-out and reproducible, allowing an easy path for future investigators to compare and contrast these results. Placenta-derived cell populations are widely available, and the authors clearly explained how the cells were processed, preserved, and delivered. With the increasing incidence of acute and chronic tendon injuries, and with the results of studies using other cell types being equivocal at best, these findings from Ma et al. are noteworthy.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
Why Are Some Patients Unhappy after “Successful” Repair of Shoulder Instability?
It has been estimated that 13% to 16% of patients who undergo arthroscopic stabilization procedures for recurrent shoulder instability are dissatisfied with their outcome, despite a technically “successful” operation. Similarly high rates of patient dissatisfaction in the face of an objectively “well-done” surgery are pervasive in most orthopaedic subspecialties and often leave both surgeon and patient frustrated and perplexed. Prior research has suggested that patient expectations, psychological characteristics, and socioeconomic factors play a major role in these cases of patient dissatisfaction. But identifying precise patient or injury factors that can alert surgeons as to which patients may be unsatisfied after their procedure has remained elusive for many common injuries.
In the June 19, 2019 issue of The Journal, Park et al. examine the bases for patient dissatisfaction after arthroscopic Bankart repair (with or without remplissage) for recurrent shoulder instability. Not surprisingly, patient age, size of the glenoid bone defect, and the number of patient postoperative instability events correlated with an objective failure of the operation (i.e., instability requiring a repeat operation). However, the study found that the number of instability events and the preoperative width of the Hill-Sachs lesion correlated with the subjective failure of the operation (i.e., the patient was dissatisfied based on response to a single question about “overall function” 2 years after surgery). For the 14 out of 180 patients who were dissatisfied despite not experiencing a revision, intermittent pain plus psychological characteristics such as apprehension and anxiety about recurrent instability were common reasons for dissatisfaction.
It is becoming clearer with each passing year that simply correcting anatomic pathologies does not always result in happy patients. Orthopaedic surgeons need to employ patient interviewing techniques to identify issues such as anxiety, depression, pain-perception concerns, and substance abuse—all of which can negatively influence the degree of patient satisfaction with the result and are somewhat modifiable preoperatively.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
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
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
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
A Rash of Broken Femoral Nails—What’s Up?
I’ll be honest: I have never worried much about breakage of the cephalomedullary nails I implant for proximal femur fractures. Instead, I’m focused on the fracture reduction, soft-tissue handling, and proper implant positioning. These nails are very strong. Sure, failures of these implants may occur and have been reported. But I have never had a lengthy discussion with a patient about the potential risk of the implant breaking during normal activity—and I doubt many other surgeons have either.
That is why the article by Lambers et al. in the May 1, 2019 issue of The Journal grabbed my attention. The authors carefully analyzed 16 cases in which a specific cephalomedullary nail (the TFNA, made from a titanium-molybdenum alloy) broke in 13 patients after an average of 5 months. Of note, 3 patients who underwent a revision with the same type of nail had a repeat fracture of the implant. The majority of these patients had been treated for a reverse oblique intertrochanteric fracture —a type that we all commonly see and treat—and all the fractures had been well reduced at the time of nail insertion.
The implant fractures all occurred at the proximal aperture of the nail and were consistent with fatigue fracture of the alloy. But they all showed a unique “stepped propagation” pattern, whereby, according to the authors, “a planar crack arrested, changed planes by 90°, progressed, arrested, and then changed planes again by 90° until final failure.”
These types of implant failures are not common for this nail, but they apparently happen more often than I thought. I am certain that the manufacturer will be responding to this data, and I look forward to future design changes—especially because the authors hypothesize that prior changes to this nail’s design and/or alloy may have contributed to these breakages. Then again, there may have been errors in technique that made these types of failures more common, or maybe a different implant would have been a better choice for some of these patients. To me, matching fracture type and implant choice is very important.
I look forward to learning more about this issue and will keep these types of implant failures in the back of my mind during hip-fracture cases. In the meantime, Lambers et al. advise “vigilant clinical and radiographic surveillance of patients with unstable hip fracture patterns who undergo osteosynthesis with use of a TFNA implant.”
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
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