JBJS Reviews Editor’s Choice—Trunnion Wear After THA
Total hip arthroplasty made its debut about 60 years ago. As with most new technologies, it was anticipated that advances and improvements would occur. However, the improvements have been incremental and in some cases have led to problems, particularly with regard to interchangeable parts, modularity, and the materials used for articulating surfaces. Some still believe that total hip arthroplasty was close to being optimized at the time that it was introduced.
Some may view these comments as somewhat provocative, but I would not be surprised if a lot of surgeons agree. The issue of trunnion wear is one example of these problems. One of the main contributing factors is the fact that each implant manufacturer uses tapers with their own specifications, which vary in terms of angle, diameter, straightness, roundness, and surface properties. Therefore, most femoral neck implant tapers are not necessarily compatible with each other. It is important to note that femoral heads should not be used interchangeably between designs as the cone angle may differ. ?If this is done, trunnionosis will be a likely outcome.
In the August 2016 issue of JBJS Reviews, Lanting et al. provide an important and very worthwhile discussion of the risk factors for trunnionosis. Trunnionosis may be enabled by the disruption of the protective oxidative layer on the metal by fretting, potentiating the corrosion of the exposed metal beneath the oxidative layer through an active combination of biochemical and electrochemical processes. Time in vivo consistently has been shown to be a risk factor for trunnionosis. Flexural rigidity of the trunnion has been demonstrated to have an important role in the development of trunnionosis. A flexible trunnion may allow fretting as well as point loading. Edge loading is known to make tribocorrosion more likely to occur. In the presence of any degree of angular mismatch, the effect of trunnionosis may be increased.
The role of design and manufacturing variables in the development of trunnion problems continues to be debated. Surgeon-related factors, especially the greater variability and taper assembly with smaller-incision surgery, also may contribute to this phenomenon. Patients presenting with unexplained pain who have modular neck-body implants should be considered to have an adverse local tissue reaction resulting from corrosion of the neck-stem interface as potential cause of the pain.
In most cases, I suspect that removal of the femoral head, cleaning of the taper, and replacement with a different femoral head (usually a ceramic head with a titanium adapter sleeve) represents adequate treatment based on care recommendations. In contrast, in cases involving adverse local tissue reactions associated with the modular neck designs, removal of the modular stem and neck may be required.
Thomas A. Einhorn, MD
Editor, JBJS Reviews
JBJS Reviews Editor’s Choice–Team Approach to Diabetic Foot Ulcers
One of the newest features from JBJS Reviews is the “Team Approach” article. Team Approach articles highlight the individual and collective importance of the multiple physician and nonphysician providers who are involved in the care of a patient. Determining how the multidisciplinary interactions and contributions are key to the understanding of a medical condition and its treatment can be essential to a successful musculoskeletal health process.
In the July 2016 issue of JBJS Reviews, Pinzur et al. describe the team approach to the treatment of diabetic foot ulcers. The authors note that an estimated 29.1 million people in the U.S. have diabetes and that, at any point in time, 3% to 4% have a foot ulcer, both of which are sobering statistics. Diabetic foot ulcers and their associated infections lead to >70,000 lower-extremity amputations yearly. Between one-third and one-half of diabetic patients undergoing major lower-extremity amputation will die within 2 years after the amputation. In order to most effectively deal with this devastating outcome, a team approach with multidisciplinary involvement is needed.
It is now accepted that the best-performing health systems are those that address challenges by developing a strategy of population management in which patients with resource-consuming medical conditions receive care across multiple medical disciplines. This strategy begins with the identification of modifiable risk factors. The most efficient patient-safety methodology for avoiding complications following surgery is to operate on healthier patients. Indeed, if we look at our orthopaedic trauma colleagues as an example, we see that survival rates and patient outcomes following hip fracture have improved since the development of systems that rapidly optimize patients prior to operative repair. This experience has taught us how important it is to have a hospitalist co-managing our orthopaedic patients. Similarly, our arthroplasty colleagues have learned that outcomes are worse and complications rates are increased in patients who have multiple medical comorbidities. Prior to urgent surgery, many of these medical conditions can be stabilized. Thus, the most proactive health systems are those that use interventions to identify and minimize health risk. When modifiable risk factors are improved, patient safety is improved.
Pinzur et al. reintroduce the concept of the so-called diabetic educator. The responsibilities of the modern diabetic educator have progressed from simple patient education on diet, glycemic control, and lifestyle change to using the educator-patient relationship to empower the educator to serve as a patient navigator/case manager. The diabetic educator and the physician also work closely with a certified pedorthist. This provider’s knowledge and skill of health maintenance through the use of therapeutic footwear are important in the prevention and treatment of diabetic foot ulcers. Patients are taught to self-examine their feet, and this level of empowerment becomes important from a psychosocial perspective.
The primary surgeon is the “captain of the ship,” and it is his or her responsibility to coordinate the management and the function of the multidisciplinary team. It is important to identify the roles of the consultants such as the certified pedorthist (who will provide guidelines on therapeutic footwear and prefabricate a custom foot orthosis as needed), the vascular surgeon (who will be needed for patients with a nonhealing foot ulcer and a nonpalpable pedal pulse), the radiologist (who will be essential for suggesting imaging modalities for understanding the disease and its progression), the infectious disease specialist (who will guide duration of therapy and monitor associated antibiotic-induced organ-system morbidity), and the plastic surgeon (who may have unique requirements for wound care and developing relationships in clinical-care algorithms).
The multidisciplinary team approach involves the use of a consistent strategy throughout the hospital or health system. This is the first step in an attempt to decrease the negative impact on quality of life and resource consumption and is essential to diabetic foot care.
Thomas A. Einhorn, MD
Editor, JBJS Reviews
JBJS Reviews to Be Indexed in MEDLINE/PubMed
The National Library of Medicine has accepted JBJS Reviews for indexing in MEDLINE/PubMed.
Launched in November 2013 and edited by Thomas A. Einhorn, MD and a distinguished editorial board, JBJS Reviews is an innovative, continuously published online review journal from the publishers of The Journal of Bone & Joint Surgery.
Each weekly posting of JBJS Reviews content updates the orthopaedic community on important topics in a concise, time-saving manner. Comprehensive reviews, special features, and integrated CME provide musculoskeletal clinicians with valuable perspectives on surgical practice and the latest advances in the field within twelve subspecialty areas.
If you are not already a JBJS Reviews subscriber, click here to learn more.
Jason Miller
Executive Publisher
JBJS Reviews Editor’s Choice–Microfracture of Articular Cartilage
Articular cartilage is a unique and complex tissue. The interactions among chondrocytes, water, and matrix macromolecules provide articular cartilage with its special properties, including the absorption and distribution of compressive loads and low-friction articulation of synovial joints. However, this complex, unique, and sophisticated tissue does not repair itself well and cartilage repair recently has become the target of numerous investigations. Indeed, the natural history of articular cartilage defects is not well defined and thus the development of treatment strategies has been limited. One technique that has gained some success is microfracture.
Microfracture is a commonly employed operative technique that is considered to be safe, relatively inexpensive, and minimally invasive as a first-line treatment for small, contained articular cartilage defects. The scientific basis of microfracture is that disruption of blood vessels in the subchondral bone will cause bleeding in the cartilage defect, leading to the formation of a fibrin clot. It has been suggested that if the clot is protected from loading, undifferentiated mesenchymal stem cells from the bone marrow will migrate into the defect, proliferate, and differentiate into fibrochondrocytes. These chondrocytes then synthesize a fibrocartilaginous matrix that fills the defects. Evidence has shown that microfracture has acceptable short-term clinical results, but those results can be expected to decline over time. What is most important for the surgeon is to determine which patients are the best candidates for this procedure and which patients should not be so treated.
Determining which patients and which cartilage defects are best treated with microfracture can be difficult. Moreover, as the results have been reported over the years, the indications for this technique have narrowed. Clinical experience has shown that lesions measuring >4 cm2 have been associated with worse outcomes. On the other hand, the minimum defect size for which microfracture should be used has not been clearly defined. Another factor is age, with younger patients having better clinical outcomes. Defect location also affects outcomes, with better results having been reported following the treatment of defects involving the femoral condyles. Finally, body mass index (BMI) is a potential risk factor for the failure of this procedure as patients with a BMI of >30 kg/m2 have had significantly lower outcomes scores and subjective ratings compared with those with a BMI below that threshold.
In the June 2016 issue of JBJS Reviews, Sommerfeldt et al. provide a critical overview of microfracture. The authors conclude that microfracture is likely to produce acceptable clinical results in the short term but that the results cannot be guaranteed over the long term. This is an important article for orthopaedic surgeons who perform this technique and for surgeons who seek to understand the basic mechanisms that support this treatment modality.
Thomas A. Einhorn, MD
Editor, JBJS Reviews
OTA Posts Disaster-Readiness Page for Surgeons
The Orthopaedic Trauma Association (OTA) just launched a page on its website devoted to disaster-preparedness resources for surgeons and first responders.
Titled “Get Prepared,” the page includes:
- A 93-slide PowerPoint presentation on orthopaedic blast injuries
- Courses from the National Disaster Life Support Foundation and the American College of Surgeons’ Committee on Trauma
- A bibliography with links to the JBJS Reviews article “Disaster Response Management Protocol for Departments of Orthopaedic Surgery” and the JBJS/JOSPT Special Report It Takes a Team—The 2013 Boston Marathon.
JBJS Reviews Author Spotlighted by KUDOS
Late last summer, JBJS began offering KUDOS as a free service to authors. KUDOS is an easy-to-use tool that helps authors boost and measure the impact of their published work.To date, 159 JBJS authors have registered with KUDOS.
Recently, KUDOS applauded Dr. Alejandro Marquez-Lara, co-author of a JBJS Reviews article about the effects of NSAIDs on bone healing, for his exemplary job summarizing and explaining the importance of his study.
On KUDOS, Dr. Marquez-Lara said the article “provides insight into the disconnect between basic science and clinical literature” on this controversial topic. He explained the predicament this way: “There is no clear evidence to support that NSAIDs inhibit bone healing in the clinical setting…but there is also no good evidence confirming the safety of NSAIDs with regards to bone healing.” He concluded by encouraging orthopaedists “to read this review to improve the quality of ongoing and future clinical studies.”
Click here to learn more about how KUDOS works and how it can help JBJS authors enhance the visibility and influence of their published research.
3-D Printing: An Orthopaedic Update
OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Chad Krueger, MD, in response to an article at MedCityNews.com that announced a 3-D printing alliance between Johnson & Johnson and HP.
There’s much focus lately on healthcare concepts in which each patient’s treatment is tailored to his or her specific condition, anatomy, and, in some cases, genetic make-up. Within that realm of so-called “personalized medicine,” surgeons are becoming increasingly interested in tailoring procedures and implants to specific individuals. The MedCity News article discusses how Johnson & Johnson has partnered with HP to further develop 3-D printing capabilities, with a goal of giving surgeons more patient-specific options.
One of the particular devices J & J is pursuing involves 3-D-printed bone-graft cages that form an osteoconductive scaffold for critical-size bone defects. Developing such a scaffold could go a long way toward promoting quicker and better outcomes in cases for which current techniques are very technically demanding. Three-D printing may eventually deliver a patient-customized scaffold that promotes bone healing, inhibits microbiologic activity, provides biomechanical strength, and is easier for surgeons to use.
The article also discusses how customized 3-D-printed implants have already been used at some facilities for “unique” patients, such as those whose challenging revision surgery would normally require substantial “trial and error” intraoperatively to properly fit implants. This printing technology can also facilitate production of customized cutting jigs, retractors, and other tools specific to individual patients. Companies are even using 3-D technology to develop casts, braces, and other interventions used in the nonoperative treatment of orthopaedic conditions (see related OrthoBuzz post).
Additionally, 3-D printing can be used in the preoperative period to provide surgeons with a better understanding of the bony anatomy they will encounter during a case. This type of preoperative templating is already being used on complex heterotopic ossification removals, spinal deformity corrections, and other difficult operations. These 3-D-printed models can also be used to educate patients and increase their understanding of the planned procedure.
Despite all the promise surrounding 3-D printing, hurdles are abundant. For example, an entirely new regulatory framework will need to be developed to ensure the quality and safety of these products. Even if the capabilities of this technology increase and the costs decrease, we must remember the many other exciting device technologies that elicited similar early excitement but were found to be less useful than anticipated.
Nevertheless, companies such as Stryker are already spending hundreds of millions of dollars to build facilities devoted to industrial 3-D printing, and they will be looking for a return on that investment. So, despite the exhilaration and promise that come with new technologies, it is important to recognize their potential limitations—and to have open discussions with patients about all that remains unknown in regard to their use.
Chad Krueger, MD is a military orthopaedic surgeon at Womack Army Medical Center in Fort Bragg, NC.
Click here to read a JBJS Reviews article about the surgeon’s role in introducing new orthopaedic technologies.
JBJS Reviews Editor’s Choice–Genomics in Reconstructive Orthopaedic Surgery
In current clinical practice, most patients who undergo total joint replacement surgery receive similar preoperative, intraoperative, and postoperative management. However, despite similar care, there is wide variability in terms of outcomes and satisfaction. This variability may be due to a lack of understanding of the genetic basis of degenerative joint disease.
Genomics, the scientific study of genes and their interrelationships with each other and the environment, has gained increased attention in the most recent decade. With the completion of the Human Genome Project in 2003, genomic research has surged, ushering in new genetic technologies and opportunities in health care. Indeed, genetic tests have been developed to identify mutations for complex diseases such as breast, colon, and ovarian cancer. These examples are but a few of the ways in which genomics can impact human disease and its prevention.
The term personalized medicine has been coined by clinicians and researchers to capture the concept that a patient’s genetic profile will determine appropriate therapy. By understanding the importance of genetics and the environment in shaping clinical outcomes, the future of medicine has the potential to provide more individualized care.
In orthopaedics, the application of genomics has centered on osteoarthritis, osteoporosis, rheumatoid arthritis, and oncology. In adult patients who undergo joint replacement surgery, the use of biomarkers and genetic testing may aid in preventing postoperative complications.
As noted above, in adult reconstructive surgery, there is a high degree of variability in patient outcomes (including complications and overall satisfaction). The key to understanding the cause of such varied outcomes may well lie in our understanding of the genetic basis of degenerative joint diseases and the genetic response to treatment. A number of conditions that occur in patients undergoing adult reconstructive orthopaedic surgery may be modifiable through the use of genomics and our understanding of them. Examples include infection, thromboembolism, heterotopic ossification, arthrofibrosis, hyperalgesia, osteolysis, and osteonecrosis. In the April 2016 issue of JBJS Reviews, Elbuluk et al. discuss the future of “orthogenomic” research, the goal of which is to establish patient-specific strategies for optimizing results and expectations after adult reconstructive surgery.
Although the application of genomics in orthopaedic practice remains limited, the framework to identify practical interventions has begun to be constructed. The ability to obtain genetic information may allow joint arthroplasty surgeons to preoperatively stratify patients according to risk on the basis of their genetic profile and establish patient-specific strategies that will optimize results after surgery. Large population-based studies will need to be conducted in order to allow orthopaedic researchers to build the necessary database to identify these genes and their biomarkers. The advent of 21st-century personalized care of orthopaedic patients undergoing total joint replacement surgery is beginning to be realized, and the future looks promising.
Thomas Einhorn, Editor
JBJS Reviews
JBJS Reviews Editor’s Choice–Steroid Injections in Patients with Diabetes
It is well known that parenterally administered steroids affect the metabolism of glucose and cause abnormal blood glucose levels in diabetic patients. For this reason, physicians are careful regarding the use of parenteral steroids in the presence of diabetes. However, one of the most common procedures in the outpatient setting, a local, intra-articular steroid injection, seems to be done without as much consideration or knowledge regarding the potential systemic effects of peripherally absorbed steroid. In the March 2016 issue of JBJS Reviews, Choudhry et al. address the question of potential abnormal blood glucose levels in diabetic patients who undergo intra-articular steroid injection.
The investigators performed a literature search of 4 different databases and identified 532 manuscripts. After applying inclusion criteria, 7 studies with a total of 72 patients were analyzed. The studies showed that a rise in blood glucose levels follows intra-articular steroid injection. Four of the 7 studies showed that this rise was substantial. Indeed, peak values as high as 500 mg/dL were reached. In most patients, hyperglycemia occurred within 24 to 72 hours after injection; however, peak increases in blood glucose levels did not occur immediately in all patients and in some cases took several days to occur.
Diabetes mellitus affects 9.3% of the general population of the United States, and nearly half of adults with diabetes also have osteoarthritis. Based on the data presented in this report, careful consideration should be given to administering intra-articular steroids to patients with diabetes. Indeed, current evidence suggests that diabetic patients should be advised to monitor their blood glucose levels following an intra-articular steroid injection. Patients with Type-1 diabetes should check their blood glucose levels 3 to 4 times a day for 7 days and should seek advice from a physician if levels exceed 360 mg/dL. Patients with Type-2 diabetes should check blood glucose levels at least twice a day for 7 days and should seek advice from a physician if levels exceed 540 mg/dL.
Intra-articular steroid injection is one of the most frequently performed outpatient procedures, and the data in this report shed important light on this process. This is a “must read” article.
Thomas Einhorn, Editor
JBJS Reviews
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