OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Grigory Gershkovich, MD.
Shoulder arthroplasty continues to grow in popularity, and as the number of shoulder arthroplasties rises, so will the number of revisions. Infection is one major reason for shoulder arthroplasty failure, and Propionibacterium has been increasingly recognized as a major culprit.
However, Propionibacterium infection is difficult to diagnose. Despite improved detection techniques, diagnosis at the time of revision remains elusive because obvious signs of acute infection are often absent. The need to perform explantation in the setting of clinically apparent periprosthetic infection is obvious, but the appropriateness of single-stage revision with antibiotic treatment in shoulders with only apparent mechanical failures remains questionable.
Hsu et al. attempted to address this question in a study published in the December 21, 2016 issue of JBJS. The group retrospectively reviewed the outcomes of 55 shoulders that underwent revision arthroplasty due to continued pain, stiffness, or component loosening without obvious clinical infection. Mean follow up was 48 months. At least five cultures were obtained intraoperatively during each revision, and each case was treated with antibiotics as if were truly infected until the final culture results were received after three weeks. Shoulders were revised to either hemi-arthroplasty, total shoulder arthroplasty, or reverse total shoulder arthroplasty.
Hsu et al. analyzed outcomes according to two groups: the positive cohort (n=27), where shoulders had ≥ 2 cultures positive for Propionibacterium, and the control cohort (n=28), where shoulders had either 0 or 1 positive culture. The two groups were compared by before- and after-revision performance on the simple shoulder test (SST) and pain outcome scores.
Both groups improved postoperatively based on these patient-reported outcome measures, and no significant difference was found between the two groups. Three patients in each group required a return to the OR. Gastrointestinal side effects were the most commonly reported complication from prolonged antibiotic administration.
This study design was limited by its retrospective nature and the lack of a two-stage revision treatment comparison group. Furthermore, this study included only patients with no signs of clinical infection, and the findings may not be applicable to patients with perioperative signs of infection. The study also incorporated three revision surgery implant options, which could have influenced postoperative SST and pain scores. Larger, multicenter controlled trials will be needed to produce a more definitive answer to this complicated question.
Still, there are clear benefits of single-stage revision over two-stage revision, especially with regard to operative time, anesthesia risks, and patient recovery. Given the wide antibiotic sensitivity profile of Propionibacterium and these initial results from Hsu et al., single-stage revision with appropriate antibiotic therapy may be suitable for patients undergoing revision shoulder arthroplasty in the setting of suspected Propionibacterium infection.
Grigory Gershkovich, MD is chief resident at Albert Einstein Medical Center in Philadelphia. He will complete a hand fellowship at the University of Chicago in 2017-2018.
Propionibacterium acnes is a frequently isolated pathogen in postoperative shoulder infections, but where exactly does it come from? According to a study by Falconer et al. in the October 19, 2016 Journal of Bone & Joint Surgery, P. acnes derives from the subdermal edges of the surgical incision and spreads through contact with the surgeon’s gloves and surgical instruments.
The authors obtained specimens for microbiological analysis at five different sites from 40 patients undergoing primary shoulder arthroplasty. Thirty-three percent of the patients had at least one culture specimen positive for P. acnes, and the most common site of P. acnes growth was the subdermal layer, followed by forceps.
The authors observed no clinical postoperative infections during the follow-up of 6 to 18 months, although that is a relatively short investigation period for a pathogen that often causes late-onset indolent infections. The authors conclude that “it is likely that surgeon handling of the skin and subdermal layer contaminates the rest of the surgical field.” Although the study did not investigate preventive techniques, based on the findings the authors suggest the following possible prophylactic approaches:
- Minimizing handling of the subdermal layer
- Changing gloves after the dermis is cut
- Avoiding contact between implants and the subdermal layer
- Repeating use of antibacterial agents once the wound is opened
The recently launched JBJS Knee Spotlight offers highly relevant and potentially practice-changing knee content from the most trusted source of orthopaedic information.
Here are the five JBJS articles to which you will have full-text access through the Knee Spotlight during the month of October 2016.
- What’s New in Adult Reconstructive Knee Surgery
- The Effect of Timing of Manipulation Under Anesthesia to Improve Range of Motion and Functional Outcomes Following Total Knee Arthroplasty
- Nonsurgical or Surgical Treatment of ACL Injuries: Knee Function, Sports Participation, and Knee Reinjury
- Topical Intra-Articular Compared with Intravenous Tranexamic Acid to Reduce Blood Loss in Primary Total Knee Replacement
- Total Knee Replacement in Young, Active Patients: Long-Term Follow-up and Functional Outcome
Knee studies offered on the JBJS Knee Spotlight will be updated monthly, so check the site often.
In the December 16, 2015 edition of The Journal, Pellegrini et al. present the results from a cohort of 23 patients who had initially undergone ankle arthrodesis and then, due to decreasing function and increasing mid- and hindfoot pain, sought relief via conversion to an ankle arthroplasty. The good news is that this conversion provided meaningful clinical improvement in pain and function, with 87% survival of the implants over the mean 33-month follow-up.
One technical detail the authors recommend is prophylactic fixation of the malleoli as a concomitant procedure, noting that local osteopenia related to arthrodesis make malleoli prone to fracture during insertion of the tibial component. It is difficult to determine if these conversions were necessitated by poor surgical technique during the original arthrodesis, but I suspect in some cases they were. Also, considering the arthritic changes to the mid- and hindfoot joints related to arthrodesis, it is easy to understand that patients would benefit from the takedown of the fusion and return of some ankle motion to diminish the stress on those joints.
Reflecting on the findings from this clinical cohort series has prompted me to change my surgical technique for ankle arthrodesis. Formerly I hemi-sected the lateral malleolus and fixed it to the talus and distal tibia. Now I preserve the distal fibula, ensure removal of all cartilage in the medial and lateral gutters, add bone graft, and provide fixation with cancellous lag screws. This change in technique facilitates takedown of the fusion and conversion to ankle arthroplasty if necessary in the future. In my opinion, the clarion call now for ankle arthrodesis must be “save the fibula!”
Marc Swiontkowski, MD
Fractures of the femoral head are uncommon. Typically associated with hip dislocations, they are found in association with high-energy trauma. They occur more commonly in men than women. Because of their relatively rare occurrence, large series with validated outcomes have not been reported. As noted by Marecek et al. in the November 2015 issue of JBJS Reviews, the goals of treatment are to achieve early and safe reduction and fixation and, in doing so, avoid complications, including osteonecrosis and heterotopic ossification.
To accomplish these goals, it is important to identify any associated life-threatening injuries and to achieve prompt reduction. A distinction is made between infrafoveal and suprafoveal fractures and the presence of associated femoral neck or acetabular fractures. Operative treatment is usually accomplished through the direct anterior or surgical hip dislocation approach, depending on the associated injury patterns. The use of mini-fragment lag screw fixation is generally preferred.
The initial treatment of femoral head fractures follows advanced trauma life support (ATLS) protocols. If hip dislocation is present, urgent reduction is performed in conjunction with skeletal relaxation to decrease the risk of osteonecrosis of the hip. Nonoperative treatment is reserved for patients with infrafoveal fractures with a concentric hip joint and no intra-articular debris and patients in whom operative intervention carries a morbid risk of complications. The timing of intervention for femoral head fractures remains controversial, and at least one randomized controlled trial demonstrated significantly worse outcomes for patients who had closed manipulative reduction and delayed open reduction and internal fixation compared with patients who received immediate operative reduction and fixation.
In summary, femoral head fractures are uncommon but severe. After prompt reduction of hip dislocations, a thorough evaluation is required to detect all associated injuries and to formulate an appropriate operative plan. Treatment should be directed toward achieving a stable, concentrically reduced hip with anatomic reduction of the fracture or excision of comminution and removal of articular debris. Arthroplasty should be reserved for patients who are older, those who have degenerative changes of the hip, and those who have complex injuries, the treatment of which would be more detrimental or risky than immediate arthroplasty.
Thomas A. Einhorn, MD
Editor, JBJS Reviews
Along with the sharply rising number of total hip and knee arthroplasties performed in the US comes an increasingly compelling need to prevent periprosthetic joint infections (PJIs). If a PJI occurs, guidelines recommend a two- to six-week post-revision course of pathogen-specific intravenous antibiotic therapy. However, the benefit of chronic suppression with oral antibiotics beyond that is unproven.
In the August 5 edition of The Journal of Bone & Joint Surgery, Siqueira et al. compared the infection-free prosthetic survivorship in 92 patients who underwent chronic oral antibiotic suppression for a minimum of six months with prosthetic survivorship in a matched cohort who did not receive extended antibiotic treatment. In so doing, they also attempted to determine factors associated with failure of chronic suppression with oral antibiotics.
The five-year infection-free prosthetic survival rate in the suppression group was 68.5% compared with 41.1% in the non-suppression group. Patients who benefited the most from chronic suppressive antibiotic therapy were:
- Those who underwent irrigation and debridement with polyethylene exchange. (Antibiotic suppression following two-stage procedures did not affect prosthetic survival.)
- Those with Staphylococcus aureus (Chronic antibiotic therapy did not influence infection-free survival after revisions for non-S. aureus infections.)
Suppression-group patients in whom antibiotic treatment failed had had more prior joint revisions and were more likely to have had a knee PJI than a hip infection.
Noting the benefit of suppressive therapy in patients who underwent irrigation and debridement with polyethylene exchange, the authors concluded that “persistence of a latent infection is common in patients with retained implants, and thus antibiotic suppression seems to be a reasonable alternative that avoids the need for a more invasive two-stage revision.”
Surgical site infections (SSIs) can cancel out the benefits of surgery, and they’re the number-one cause of hospital readmissions following surgery. The most prevalent pathogenic culprit is Staphylococcus aureus.
A study of patients undergoing cardiac or hip or knee arthroplasty surgery at 20 hospitals in nine states found that the following protocol reduced the rate of complex (deep incisional or organ-space) S. aureus SSIs by about 40% overall—and by about 50% among patients undergoing hip or knee arthroplasty (an absolute difference of 17 infections per 10,000 joint replacements):
- Preoperative screening of nasal samples
- Intranasal mupirocin and chlorhexidine baths for up to five days prior to surgery for patients testing positive for methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus (MSSA)
- Perioperative prophylaxis with vancomycin plus cefazolin or cefuroxime for MRSA carriers and perioperative cefazolin or cefuroxime for all others
Rates of complex SSIs decreased most substantially among patients who were fully adherent to the protocol, although only 39% of the subjects experienced implementation of all the steps. Adherence rates were especially low among those who presented in urgent and emergency settings.
In an editorial accompanying the study, Preeti Malani, MD wrote that “although the absolute difference [in infections] seems modest, each complex SSI prevented is clinically meaningful.”
Surgeons performed more than 1.1 million joint replacements in the US in 2011. That same year, the International Consortium of Orthopaedic Registries (ICOR) was launched to help close gaps in evidence and data collection related to orthopaedic implants. The ICOR network now consists of more than 70 stakeholders and more than 30 orthopaedic registries representing 14 nations.
The December 17, 2014 edition of The Journal contains an online supplement with 14 articles highlighting the achievements of international registries and the findings from 12 ICOR-initiated registry studies. The first article in the supplement (National and International Postmarket Research and Surveillance Implementation) summarizes the findings from the 12 registry studies. The second article (A Distributed Health Data Network Analysis of Survival Outcomes) provides an overview of the data extraction processes and analytic strategies used in the studies.
Key findings from the 12 studies contained in the supplement:
- Effect of Femoral Head Size on Metal-on-HXLPE Hip Arthroplasty Outcome in a Combined Analysis of Six National and Regional Registries
There were no differences in revision risk when metal-on-HXLPE (highly cross-linked polyethylene) implants with larger and smaller femoral head sizes were compared.
- Risk of Revision Following Total Hip Arthroplasty: Metal-on-Conventional Polyethylene Compared with Metal-on-Highly Cross-Linked Polyethylene Bearing Surfaces
Non-cross-linked polyethylene was not associated with significantly worse revision outcomes when compared with metal-on-HXLPE.
- Distributed Analysis of Hip Implants Using Six National and Regional Registries: Comparing Metal-on-Metal with Metal-on-Highly Cross-Linked Polyethylene Bearings in Cementless Total Hip Arthroplasty in Young Patient
Large-head-size metal-on-metal implants were associated with increased risk of revision after two years, compared with metal-on-HXLPE implants.
Use of ceramic-on-ceramic implants with a smaller head size was associated with a higher revision risk compared with metal-on-HXLPE implants and ceramic-on-ceramic implants with head sizes >28 mm.
- Multinational Comprehensive Evaluation of the Fixation Method Used in Hip Replacement: Interaction with Age in Context
When compared with hybrid fixation, cementless fixation was associated with an approximately 58% higher risk of revision surgery in patients aged 75 years or older.
- International Comparative Evaluation of Knee Replacement with Fixed or Mobile Non-Posterior-Stabilized Implants
Mobile-bearing, non-posterior-stabilized knee designs presented a 40% higher risk of failure than that found with fixed-bearing, non-posterior-stabilized designs.
- International Comparative Evaluation of Knee Replacement with Fixed or Mobile-Bearing Posterior-Stabilized Prostheses
Compared with fixed-bearing posterior-stabilized knee prostheses, patients who received mobile bearings had an 85% higher chance of revision within the first postoperative year.
- International Comparative Evaluation of Fixed-Bearing Non-Posterior-Stabilized and Posterior-Stabilized Total Knee Replacements
Fixed non-posterior-stabilized (cruciate-retainin0 TKA performed better (with or without patellar resurfacing) than did fixed posterior-stabilized (cruciate-substituting) TKA.
- Survivorship of Hip and Knee Implants in Pediatric and Young Adult Populations: Analysis of Registry and Published Data
Reported revision rates of TKA and THA among pediatric and young-adult patients is currently similar to that for older patients, but the dearth of data makes it incumbent on registries to continue collecting and analyzing data relevant to younger populations.
This systematic review and meta-analysis concluded that surgeons performing a primary THA should use an implant that outperforms benchmarks established by the UK’s National Institute for Health and Care Excellence (NICE).
- Review of Clinical Outcomes-Based Anchors of Minimum Clinically Important Differences in Hip and Knee Registry-Based Reports and Publications
Among 19 registry reports and 1052 articles examined, only one report and two studies mentioned patient-reported outcome measures (PROMs) and minimum clinically important differences in connection with revision rates after TKA or THA.
- Implementation of Patient-Reported Outcome Measures in U.S. Total Joint Replacement Registries: Rationale, Status, and Plans
Successful collection of PROM data is possible with careful attention to selection of outcome measure(s) and minimizing the data-collection burden on physicians and patients.
Perhaps more than any other advance in orthopaedic surgery, total joint arthroplasty has improved the lives of millions of patients. Originally introduced in the form of hip replacement, nearly all of the major joints of the musculoskeletal system can now undergo arthroplasty, and total knee arthroplasty has established itself as one of the most successful interventions for reducing pain and improving function and quality of life. All total joint arthroplasties are associated with a risk of failure, and it is believed that, with the exception of the oldest patients, most individuals who undergo an arthroplasty will require a revision at some point during their lifetime. With total knee arthroplasty, advances in implant materials and design as well as operative technique have increased implant longevity and decreased the rate of revision to <5% within ten years.
As is typical of a successful intervention, surgeons who perform total knee arthroplasty recognize the need or opportunity to “push the envelope.” There is great demand for offering knee arthroplasty to younger, more active patients, and, in doing so, it is projected that the number of revision procedures will grow from the current annual incidence of 38,000 up to 270,000 by the year 2030. Thus, understanding the causes of failure will be essential for guiding future strategies.
In this month’s article by Bou Monsef et al., a systematic approach to identifying mechanisms of failure and appropriate treatment protocols for failed total knee arthroplasty are introduced. The authors make the important point that avoiding operative intervention before a diagnosis is made, even in cases of pain with no clear etiology, is essential. Individual discussions on the roles of infection, loosening and component failure, instability, stiffness, patellofemoral complications, and even neuromas are presented and placed in their proper perspective.
Indeed, one of the greatest frustrations in orthopaedic practice is the inability to identify the causative factors for a condition. The failure of a total knee arthroplasty may be associated with one or more contributing factors, including rare and unusual conditions such as the formation of heterotopic bone, the development of complex regional pain syndrome, the occurrence of hemarthrosis, and even hypersensitivity to certain metals. Interestingly, up to 17% of the general population expresses some sensitivity to the metals used in total knee implants such as nickel, chromium, and cobalt.
Failure of total knee arthroplasty can be devastating to the patient, but early diagnosis and careful systematic analysis of the potential etiologies can lead to a favorable outcome. This article provides a clear and concise approach to this problem and is a “must read” for surgeons who perform this operation now and the residents and fellows who will be caring for these patients in the decades to come.
Thomas A. Einhorn, MD, Editor
Thomas Thornhill, MD is the John B and Buckminster Brown Professor of Orthopaedic Surgery at Harvard Medical School and Chair of the Department of Orthopaedics at Brigham and Women’s Hospital in Boston. He recently was kind enough to answer a few questions for OrthoBuzz.
JBJS: What are some of the most significant changes in orthopaedics you have observed during your career?
Dr. Thornhill: The quality of applicants to orthopaedic residency programs seems to improve every year. I think anyone involved today in choosing new residents feels that he or she would never have been chosen by contemporary standards. Moreover, our profession has become more diverse, which is a good thing. Our residency/fellowship program has a significant number of women and underserved minorities. The most impressive thing is that there is a single set of criteria for all applicants, giving us a uniformly outstanding resident pool.
Also, the emerging use of biologics has enhanced our ability to care for some common and uncommon musculoskeletal problems. For example, the use of disease-modifying anti-rheumatic drugs (DMARDs) has revolutionized the care of the rheumatoid patient. When I began practice, 80 percent of patients undergoing total joint arthroplasty had rheumatoid arthritis, and now it is only approximately 10 percent in a center well-known for treating the rheumatoid patient.
Third, I’ve seen significant changes in the globalization of orthopaedics. The internet and social media have improved global communication. Many of the meetings in arthroplasty are global in their scope, and we are learning a tremendous amount from our orthopaedic colleagues around the world.
JBJS: Brigham and Women’s Hospital is recognized as a leader in providing patient-centered, team-based care. Why is this approach so important to orthopaedic patients?
Dr. Thornhill: Brigham and Women’s Hospital does not exist in a vacuum, and the Boston area has many fine academic and community hospitals with strong orthopaedic programs. Each subscribes to the concept of providing the right care, at the right place, and at the right time. Moreover, the changes in healthcare systems in Massachusetts and throughout the United Sates require each of us to be innovative. In the past, clinical surpluses could be used for educational and research program funding, but with the shrinking healthcare economy, there are many essential, but non-remunerative programs that are in jeopardy. Efficient, team-based care is one way to ensure we have the resources to continue these important educational and research programs. Finally, the switch from fee-for-service to episode-of-care reimbursement and population health is going to require each of us to adjust to inevitable changes in healthcare. In this environment, patient-centered, team-based care makes the most sense to ensure optimal outcomes.
JBJS: Orthopaedists are increasingly focused by subspecialty. What do you see as the benefits and risks of increased subspecialization within orthopaedics?
Dr. Thornhill: We are indeed becoming more and more subspecialized. One benefit is that it will certainly improve expertise in these areas, where patient demand is growing in an exponential fashion. It will also allow specialists to remain current in their subspecialty and prompt innovation in these different fields of orthopaedic practice.
On the other hand, intensive subspecialization may prevent us from “thinking outside the box.” Communication and idea crossover are important, and while we know many of the leaders in our own subspecialty, we don’t know many in other areas. Most of the meetings now are subspecialty-driven and fail to benefit from sharing of ideas with other subspecialties. Our graduates now virtually all take a fellowship, and 15 percent of them take two fellowships. One could argue that a trauma surgeon or musculoskeletal oncologist should have arthroplasty experience because there is a good deal of overlap within these disciplines. We should also remember that lessons learned in one specialty may benefit another. For instance, hip surgeons have long considered neck shaft angle, offset, and even material properties that have now been incorporated into the design and implantation of shoulder prostheses.
JBJS: How do you think JBJS can best address the needs of the orthopaedic community in light of this increasing subspecialization?
Dr. Thornhill: JBJS needs to maintain its preeminence as the leading orthopaedic journal. To do so, it must remain relevant, explore other mechanisms in addition to a printed version to transmit information, and the articles must remain balanced throughout the various subspecialties. I think JBJS has done an outstanding job moving into electronic media. One concern is the economics of maintaining The Journal’s viability and the concerns of some young authors about the cost of submitting a manuscript.
JBJS: Looking ahead to the next 20 years or so, what three significant advances or changes in orthopaedics do you foresee?
Dr. Thornhill: To paraphrase the book Future Shock, “If you want to see what is in the future, look around because it is happening somewhere now.” I think there will be an increased use of biologics in applications such as induction of bone formation, cartilage repair, tissue engineering, and the use of stem cells for repairing and regenerating musculoskeletal structures.
Also, we will look back several years from now and laugh at the materials we currently use for total joint replacement. One important concern in my area of interest is that 15 to 20 percent of patients undergoing total knee replacement are not completely satisfied, while many people with total hips and total shoulders forget they had an implant. I think the cause is multifactorial, but I do think that we will develop or engineer materials with characteristics that will improve the kinematics of knee prostheses, and hopefully our patients will feel that their knee replacements are more normal.
Finally, there will be an increase in technology, manufacturing, and research and development on a global scale. Global cooperation and time zone differences can allow manufacturing, design, and outcome studies to occur 24-7 in a more cost-effective fashion. If we also foster the interactions between academia and industry in a controlled fashion, we will further appreciate the tremendous advances in our specialty due to these relationships.
JBJS: What is your favorite thing about your profession?
Dr. Thornhill: The hackneyed phrase is that we get instant gratification from pain relief and restoration of function in our patients. While this is true, when I trace my training from internal medicine to orthopaedics, I recall drawing a Venn diagram showing that the three things I liked the best were surgery, rheumatology, and neurology. The only true intersection among those is orthopaedics. I would say that other than my family, I appreciate my interactions with students, residents, fellows, and colleagues, and I thoroughly enjoy treating my patients as people. Finally, I like the operating room and the technical aspects of orthopaedics.
JBJS: Thank you, Dr. Thornhill, for your time.