Infection, whether acute, chronic, local, or systemic, is something that all surgeons respect and fear. To counter infection, tissue injury activates an acute-phase response mediated by the liver and promotes coagulation, immunity, and tissue regeneration. However, microorganisms are able to survive and disseminate throughout tissues because of virulence factors that they express. These virulence factors help to modulate and hijack the acute-phase response.
In this month’s Editor’s Choice article, An et al. discuss how an understanding of virulence strategies of musculoskeletal pathogens will help to guide clinical diagnosis and decision-making through monitoring of acute-phase markers such as C-reactive protein, the erythrocyte sedimentation rate, and fibrinogen. As pathogenic bacteria possess virulence factors that allow them to invade, persist, and disseminate within the human body, this review focuses on the pathophysiology of musculoskeletal infection and the virulence factors that enable pathogens to thrive within the context of tissue damage.
The authors demonstrate that tissue injury ruptures anatomic compartment boundaries, leading to the contamination of microenvironments that require complex physiological processes for proper temporary repair. Certain organisms, such as Staphylococcus aureus and Streptococcus pyogenes, have evolved mechanisms for evading and hijacking the hemostatic, tissue regenerative, and antimicrobial properties of the acute-phase response. Indeed, a better understanding of the virulence strategies used by pathogenic microorganisms should enhance our ability to treat infections and improve patient outcomes in the future.
Thomas A. Einhorn, MD
Editor, JBJS Reviews
One key question for orthopaedic surgeons regarding revision total knee arthroplasty (TKA) is how best to affix femoral and tibial stems. The August 17, 2016 edition of the Journal of Bone & Joint Surgery contains findings from a Level I randomized trial by Heesterbeek et al . that addresses this clinical conundrum.
Thirty-two patients with Type-I or II bone defects who needed a revision TKA received the same basic implant, with the femoral components and tibial baseplates being cemented in all cases. However, in half the patients the femoral and tibial stems were cemented, and in the other half the stems were press-fit (so-called hybrid fixation).
Measuring micromotion with radiostereometric analysis (RSA) at baseline, 6 weeks, and 3, 6, 12, and 24 months, the authors found no significant between-group differences in component migration. Similarly, at the 2-year follow-up, there were no significant between-group differences in clinical scores, including KOOS and visual analog ratings of pain and satisfaction.
The authors expressed concern about what they deemed the “relatively high” number of components in both groups that migrated > 1 mm (translation) or > 1° (rotation), and they are continuing to follow all these patients to determine whether clinically relevant component loosening eventually ensues.
According to a report on Medscape.com (registration required), for Francisco Velazco, an unemployed Seattle handyman, an online auction yielded an affordable solution to getting his torn ligament repaired. Without health insurance and unable to pay the $15,000 estimated cost from a local provider, Velazco turned to MediBid, an online medical auction site that matches patients who are seeking non-emergency treatment with physicians. MediBid doesn’t check provider credentials but requests physician license numbers so prospective patients can check on the physician’s credentials themselves.
Valazco paid $25 to post his request for surgery and a few days later he had bids for outpatient treatment from surgeons in New York, California, and Virginia. One bid for $7,500 included the anesthesia and related costs and information about orthopaedist Dr. William T. Grant in Charlottesville, Virginia. Velazco eventually underwent surgery in an outpatient surgical center that Dr. Grant co-owns. This was Dr. Grant’s first MediBid case, and he said, “I was certainly invested in wanting this to be a positive experience for everybody.” According to Velazco, the experience was ideal.
About 120,000 consumers have used MediBid, with many of them uninsured or covered by high-deductible health plans. On the provider end, there are about 6,000 physicians or surgery centers on board with MediBid, and they too pay a fee to bid on requests.
Not surprisingly online auctions for medical services have critics, among them Arthur L. Caplan, head of the division of bioethics at New York’s Langone Medical Center, who said, “Cheap sounds good, but in these auctions you’re not getting any information: Was the guy at the bottom of his class in medical school?”
Currently, each year more than 300,000 Americans sustain a hip fracture, and that number is expected to rise to more than 500,000 within the next 20 to 30 years. A new study– based on a literature review, analysis of Medicare claims, and input from clinical experts–finds that the average lifetime societal benefit from surgery to repair hip fractures reduced the direct medical costs of the surgery by $65,000 per patient. Collectively, that results in an estimated $16 billion lifetime societal savings. These savings include reductions in length of and intensity of postinjury care, and the amount of required long-term medical care and assistance required by surgery patients relative to those whose fractures are treated nonsurgically. The study, published in Clinical Orthopaedics and Related Research, also found that the quality-adjusted life years in people with surgically treated hip fractures increased 2.5 years for patients with intracapsular fractures and 1.9 years for those with extracapsular fractures. To view a summary of the article, read here.
The Zip Surgical Skin Closure device from ZipLine Medical (Campbell, CA) is an intriguing recent evolution in surgical wound closure. If the experiences of two orthopaedic surgeons from OrthoIndy in Indianapolis are any indication, this innovative method could be poised for clinical take-off.
Jack Farr, MD and David A. Fisher, MD, (both authors of JBJS-published papers) have observed improved patient satisfaction with Zip, as compared with sutures or staples. In an article they contributed to Orthopedics This Week (subscription required), Drs. Farr and Fisher also tout the theoretical reduction in infection risk, seeing as Zip closes wounds without perforating the skin.
The Zip attaches to the skin adjacent to the incision with a hydrocolloid adhesive. The individual straps for wound tensioning carry the potential to distribute closing forces more evenly than sutures or staples, and “in our experience, applying the Zip took about the same amount of time as applying staples,” Farr and Fisher wrote. The incision remains exposed in the center of the device so absorptive dressings placed on top can collect wound exudates.
Another significant advantage is the increased range of motion that Zip allows due to the device’s “programmed separation” feature, which permits it to lengthen upon joint flexion without stressing the incision. Four days after partial knee replacement surgery closed with Zip, Dr. Farr himself was using a stationary bike. Farr and Fisher also report reduced patient apprehension about removal. Zip is simply peeled off, easing the trepidation that’s often associated with staple removal.
Although the OrthoIndy experience with Zip has been uniformly positive, it has been anecdotal. To bolster the evidence base, Drs. Farr and Fisher (neither of whom reportedly has any financial stake in ZipLine Medical) are planning a prospective randomized, controlled study on “bilateral partial or total knee patients to measure the differences between the Zip and staples.”
For any number of reasons, regulatory issues among them, orthopaedic innovations in China often have modest relevance for the practice of orthopaedics elsewhere in the world, but that doesn’t make them any less fascinating.
Case in point: According to Becker’s Spine Review, surgeons in China recently implanted the first-ever 3D-printed cervical disc in a 12-year-old boy. The surgeon, Dr. Liu Zhongjun, described the procedure as successful, although the patient will have to remain in a head frame with pins for three months.
The Becker’s story did not specify the material from which the cervical disc was printed, but 3D printing is capable of producing porous metal implants, and companies have reported success with 3D-printed implants made from thermoplastic materials.
One theoretical advantage of 3D-printed orthopaedic implants is that they can be customized based on digital images of a patient’s actual anatomy. That would conceivably result in a better fit, quicker recovery, and fewer complications.
Still, don’t expect to find a 3D prosthetic printer in your hospital anytime soon. Clinical studies required to ensure the safe and effective use of even the most promising new technologies take years. And even after such studies are completed, regulatory approval and coverage from payers is not guaranteed.
The treatment of periprosthetic infection remains one of the most difficult and challenging problems in orthopaedic surgery. Conventional approaches such as the use of tissue and/or fluid cultures to identify and treat organisms are not nearly as successful as they need to be in order to address these conditions. The limitations of treatment, including the inaccessibility of microorganisms at the time of irrigation and debridement, the development of resistant strains of microorganisms, and the elaboration by microorganisms of protective biofilms, have led to unsuccessful outcomes in a large number of cases.
In this issue of JBJS Reviews, Chen and Parvizi provide an update on some of the new methods that may possibly advance this field. Molecular methods such as polymerase chain reaction to amplify bacteria can improve the likelihood of identifying the pathogen in a patient with a periprosthetic joint infection. Synovial markers such as C-reactive protein, leukocyte esterase, α-defensin, human β-defensin-2 (HBD-2) and HBD-3, and cathelicidin LL-37 are known to be elevated in patients with periprosthetic joint infection and may be used as markers for diagnosing infection at the time of operative management. Serum markers such as interleukin-4 (IL-4) and IL-6, and others such as soluble intracellular adhesion molecule-1 (sICAM-1) and procalcitonin (PCT), have been shown to be elevated in patients with periprosthetic joint infection.
Molecular detection methods probably have received the most attention and interest as an advancement that may improve our ability to diagnose periprosthetic infections. The limitations of these methods, however, include their high sensitivity and an increased rate of false-positive results. Methods to reduce the number of false-positive results are currently in development and include, among other things, the measurement of 16S ribosomal RNA in the belief that targeting RNA will result in amplification of only the genetic material of live bacteria. In addition, use of the mecA gene for identifying methicillin-resistant Staphylococcus aureus (MRSA) can reduce this rate.
Although this article does not provide definitive new approaches to the problem, the review of recent advances with the development of promising biomarkers and molecular techniques provides optimism that this field is evolving in a positive way.
A recent study by the AMA Insurance Agency of 125,000 practicing physicians spanning across a broad spectrum of specialties found many significant differences in work/life profiles by age.
For example, almost 75% of physicians under the age 40 have student loan debt, with almost half owing $150,000 to $200,000. Eighty-three percent of all physicians are still paying off their loans. Nearly one out of four of physicians under 40 plans on changing employers in the next 5 years, while 44% of those 60 to 69 plan on retiring during that same timeframe. Retirement savings is a top concern of all physicians regardless of age. Half of the doctors surveyed said they are behind in their retirement plans with only 6% indicating they are where they think they should be.
Despite the fact that nearly 25% of the physicians surveyed work 60 to more than 80 hours a week, they are still very physically active outside of their profession. The top activities include running/jogging, bicycling, aerobics, and camping/hiking.
Among 25 medical specialties, orthopaedic surgery ranked highest on payscale, according to Medscape’s 2014 Compensation Study (registration/login required). With an average annual salary of $413,000 in 2013, orthopaedists were followed by cardiologists with an average salary of $351,000 and urologists and gastroenterologists (tied at $348,000). The lowest-earning specialists were HIV/ID physicians, family- and internal-medicine doctors, and pediatricians, all making less than $200,000. Relative to 2012, orthopaedists experienced an increase of nearly 2%, while rheumatologists reaped the biggest year-to-year increase in pay, with a jump of 15%. A gender gap remained, with the average salary for male orthopaedic surgeons at $418,000, compared to female surgeons at $354,000. Geography also impacts salaries. The highest-paid orthopedists live in the Northwest and the Great Lakes regions. When asked whether they would choose the same specialty if given the chance to start over, 64% of orthopaedists said they would. However, despite the high salaries, Medscape’s study placed orthopaedists in the middle of the pack for overall career satisfaction.