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Antibiotic-Laden Cement Lowers TKA-Revision Rates in US Veterans

We recently celebrated Veteran’s Day with the annual tradition of rightfully honoring the men and women who have served in the Armed Forces. After their active duty ends, servicemembers are eligible for care in Veterans Health Administration (VHA) hospitals around the nation. The VHA is a “closed” medical system that affords ample opportunity for population-based research.

In the November 18, 2020 issue of The Journal, Bendich et al. utilized VHA data to compare revision rates after primary total knee arthroplasty (TKA) among veterans treated with antibiotic-laden bone cement (ALBC) or plain cement. Although results of similarly designed studies focused on this question have been equivocal, antibiotic-laden cement seems to be especially effective at preventing infection in higher-risk populations, which is what the US veteran population is considered to be.

The researchers identified 15,972 primary TKAs that were implanted using Palacos bone cement between 2007 and 2015. Approximately 70% (11,231) of those cases used cement mixed with gentamicin, while 30% (4,741) utilized plain bone cement. The authors found similar patient demographics among patients treated with ALBC and those treated with plain cement, but ALBC was used more frequently in patients with higher comorbidity scores.

Overall, utilization of ALBC increased from 50.6% of the cases in 2007 to 69.4% in 2015. At a follow-up of 5 years, ALBC TKAs had a lower all-cause revision rate (5.3%) than plain-cement TKAs (6.7%) and a lower rate of revision for infection (1.9% compared to 2.6%). Even after multivariable adjustments to account for patient, surgical, and hospital factors, these revision-rate differences remained.

Bendich et al. also found that 71 TKAs needed to be implanted with ALBC to avoid 1 revision TKA. With a cost differential of $240 per case for ALBC, I think spending $17,040 ($240 × 71) is more cost-effective than 1 revision TKA, although a formal cost analysis is warranted.

In the interest of full disclosure, as an active-duty US Air Force officer, I am inherently biased, but I feel that no cost is too great to improve the health of our veterans. The authors review arguments against using ALBC, such as a theoretical risk of poor cement mechanical properties and systemic toxicity, but the findings of this study suggest that cement with antibiotics enhances treatment outcomes among these US heroes.

Click here to view the “Author Insight” interview about this study with co-author Alfred Kuo, MD, PhD.

Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media

The Challenges of Complex Revision Elbow Arthroplasty

Lower-extremity joint replacement is quite well-advanced, thanks to a high incidence of disabling osteoarthritis and a 40-plus-year history of development in hip and knee prostheses. Additionally, during the last 5 to 10 years, we have made progress in prosthetic design and reliable surgical techniques for the ankle. In the upper extremity, we have a similar 4-decade development history with anatomic shoulder replacement and now 10-plus years with increasingly reliable reverse total shoulder arthroplasty.

However, techniques for elbow and wrist arthroplasty have been much slower to develop, due to lower incidence of pathology, the unique functional demands on these joints, and prosthetic-design and fixation issues. Still, the Conrad-Morrey family of implants has provided reliable elbow prostheses for more than 20 years. Meanwhile, the indications for elbow arthroplasty have narrowed to inflammatory arthritis and distal humeral fractures and nonunions in patients with lower functional demands. Unfortunately, failure of fixation, infection, and bone resorption do occur after primary elbow arthroplasty; consequently, a small but growing number of patients face revision elbow arthroplasty.

In the November 18, 2020 issue of The Journal, Burnier et al. report the results of revision elbow arthroplasty using a proximal ulnar allograft-prosthetic composite to compensate for missing ulnar bone stock and triceps tendon insufficiency. They clearly explain the surgical technique and report their results among a 10-patient cohort, including details of the 6 cases that required reoperation.

JBJS will continue reporting results of revision joint arthroplasty because members of the orthopaedic community have to manage these very complex cases, and this type of information is helpful to guide treatment decisions and patient expectations. Equally important is the positive impact this information has on further development of surgical techniques and prosthetic designs. Close examination of failure is the fuel for innovative improvement.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

Balancing Antibiotic Perfusion and Tourniquet Usage

Antibiotics are an integral part of infection prophylaxis in orthopaedic surgery, and tourniquets are widely used during many of those same surgeries. The timing of antibiotic administration in relation to tourniquet use has long been debated. Hanberg et al. explore this “balancing act” in the November 4, 2020 issue of The Journal in a carefully performed animal study.

The researchers anesthetized 24 female pigs and surgically exposed both of their hind calcanei. They then placed microdialysis catheters through drill holes in each calcaneus and also into the subcutaneous adipose tissue in the hind feet. Tourniquets were applied to one hind leg on each animal, and each pig was then randomized into 1 of 3 groups, based on when the animal received 1.5 gm of cefuroxime intravenously:

  • Group A –15 minutes prior to tourniquet inflation
  • Group B – 45 minutes prior to tourniquet inflation
  • Group C – At the time of tourniquet release

Hanberg et al. inflated the tourniquets for 90 minutes in all 3 groups, and then they measured the concentrations of cefuroxime and ischemic markers at regular intervals between the time of tourniquet inflation and up to 480 minutes afterward.

The authors found that in both Groups A and B, cefuroxime concentrations were maintained above the minimum inhibitory concentration (MIC) for Staphylococcus aureus in cancellous bone and adipose tissue throughout the 90 minutes of tourniquet inflation. In addition, injecting cefuroxime at the time of tourniquet deflation (Group C) kept the tissue-antibiotic levels above the MIC on the tourniquet side for 3.5 hours after tourniquet release.

There were no differences in the time above MIC in bone or adipose tissue between the 3 groups, but the researchers noted a trend toward shorter time above MIC in bone in Group A vs. Group C (p=0.08). There was also a tendency toward higher time above MIC in bone on the tourniquet side compared to no-tourniquet side in Group B (p=0.08) and Group C (p=0.06). The researchers also found that, in all the animals, tissue ischemia persisted for 2.5 hours after tourniquet deflation in bone, while the adipose tissue recovered immediately.

This animal study provides useful data and prompts us to ponder ideas for further investigation regarding the interplay between tourniquets and antibiotic perfusion. For example, I think the prolonged ischemia in cancellous bone is a topic that warrants further investigation, and I am also curious whether adding antibiotics at the time of tourniquet release might help combat the potentially negative effects of that ischemia.

Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media

History Counts–And It Needs to Be Complete

Joel L. Boyd, MD

It has often been shown that those who do not study history are doomed to repeat its mistakes. The Journal of Bone & Joint Surgery has a >130-year history, which we must continue to review. Understanding our history is so important that JBJS staff and trustees have invested in a 6-month project to get our history encapsulated and published on our website for continuous reference and reflection. The history of our journal contains mistakes—one stark example of which is promulgating the use of metal-on-metal arthroplasty.

But history is not complete until all the stories are told. Incomplete history is particularly evident with our North American native populations and individuals of African heritage. Here history is recorded with formerly conscious and now primarily unconscious (I hope) bias against accurately detailing the important contributions of native and Black citizens.

In the November 4, 2020 issue of The Journal, Dr. Joel Boyd does us great service by setting the record straight regarding the contributions of Black Canadians and Americans to the sport of ice hockey. (Our collective history in orthopaedics has particular relevance in sports.) Black athletes were on the ice at the sport’s very inception and in the early formation of competitive leagues. Dr. Boyd’s history, which focuses on the Black Hockey League of the Maritimes and  Willie O’Ree, the “Jackie Robinson of hockey,” is replete with bias against acknowledging these contributions and against allowing non-Whites to compete for the sport’s highest trophies.

Let us all study these contributions, recognize their importance, and vow to be ever-vigilant for any bias, conscious or unconscious, in our thinking and conduct. May Dr. Boyd’s important exercise in completing this bit of history repeat itself in sport, science, and medicine across the board.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

Detecting Pathogens in Pediatric Infections: Swab, Tissue, or Bottle?

Identifying the pathogenic microorganism in childhood osteomyelitis and septic arthritis is essential to tailoring appropriate treatment. But the traditional methods of swab and tissue culturing have subpar success rates in pediatric patients, identifying the pathogen in only 40% to 60% of cases. In the October 21, 2020 edition of The Journal, Shin et al. report their findings comparing microbial identification rates using pediatric blood culture bottles (BCBs), typical culture swabs, and tissue specimens.

Over 3 years, the authors prospectively collected intraoperative specimens from 40 pediatric patients (mean age of 7.2 years) who underwent surgery for a presumed osteoarticular infection. Half of the patients had received oral or intravenous antibiotics in the 3 weeks prior to surgery, while the other half had received intravenous cefazolin after culture specimens were obtained in the operating room. Intraoperative culture specimens were obtained in 3 different manners for all patients:

  1. Four 21-gauge needles were dipped into the infected fluid and were used to inoculate 4 pediatric BCBs – 2 aerobic and 2 nonaerobic.
  2. Two swabs were placed in direct contact with the infected tissue.
  3. Two solid tissue samples were collected and placed in 2 sterile containers.

In these 40 cases, the microbial identification rate of the BCB method was 68%, compared to 45% with the swab method and 38% with the tissue method—all statistically significant differences. In 9 patients (23%), the pathogen was only identified with the BCB method. No samples showed positive culture growth with the other 2 methods if the BCB culture was negative. Interestingly, in a subgroup analysis of 15 patients with methicillin-susceptible Staphylococcus aureus (MSSA), the authors found no difference in detection rates between the 3 methods, but in cases involving organisms other than MSSA, detection with BCBs was significantly higher than with both swab and tissue cultures.

The apparent superiority of BCBs to detect microbial organisms could be due to the characteristics of pediatric BCBs, which enhance microorganism growth in a small amount of liquid. Although there are some concerns that this enhanced BCB detection could lead to increased rates of false-positives from contaminants, I think the risk of false positives is a viable tradeoff if we can more quickly and accurately identify pathogens in pediatric infections. As Shin et al. emphasize, “Sequelae resulting from these infections are particularly unfortunate for pediatric patients.”

Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media

Using Registries to Investigate Rare Diseases

There has been a huge worldwide effort over the last 2-plus decades to establish arthroplasty registries. Among the many advantages of such registries, advocates emphasize the potential detection of early failures associated with new implant designs and biomaterials. The large number of patients enrolled in most registries and the methodical capturing of data yield substantial statistical and research benefits.

Based on the successes of arthroplasty registries, parallel registries have been established for sports medicine (especially for shoulder and knee conditions and treatments), fractures, musculoskeletal tumors, and others. Although the focus has been on enrolling large numbers of patients with relatively common disorders or procedures, there have been less well-publicized efforts to create smaller registries of rarer diseases.

In the October 21, 2020 issue of The Journal, Forman et al. use the 8-site Congenital Upper Limb Differences (CoULD) registry to report on associations between congenital deficiency of the radial aspect of the forearm in 259 patients (383 involved limbs) and thumb hypoplasia. Two findings stood out to me:

  • The severity of radial deficiency was correlated with the severity of thumb deficiency.
  • Compared with subjects who had no diagnosed syndromes, patients with concomitant syndromes (such as VACTERL and Holt-Oram) were twice as likely to have bilateral deficiency and 2.5 times as likely to have radial and thumb deficiencies as opposed to thumb deficiency alone.

In addition to reinforcing findings from previous single-institution studies, these data from Forman et al. will help surgeons counsel parents, determine treatment approaches, and establish frameworks for following patient outcomes after both surgical and nonsurgical treatment. It is my hope that other clinician-researchers with interest in understanding and managing rare conditions will establish similar registries to benefit these smaller but no-less-important groups of patients and families.

Click here to read the JBJS Clinical Summary on Congenital Hand Differences.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

Complex Technology Demands Conflict-Free Reporting

In the October 7, 2020 issue of The Journal, Du et al. report on a multicenter database-derived cohort of 167 patients with early-onset scoliosis treated with traditional growing rods and followed for ≥2 years after “final” fusion. These researchers report that 19% of those patients required a repeat surgery following fusion, most commonly for surgical-site infection and anchor-site failure. Multivariate analysis of risk factors for reoperation following final fusion revealed the following:

  • Curve progression requiring revision surgery during the spine-lengthening process
  • The number of levels spanned with the growing rods
  • The duration of treatment

Du et al. report these results without spin in a way that is most useful for surgeons who are considering using these implants in their armamentarium. This is the way all new technology, especially complex advances in surgical care, should be reported.

Orthopaedic implants and instruments continue to evolve, almost always toward more sophisticated digital technology, complex engineering, and more numerous moving parts. The advent of magnetic growing rods for treating early-onset scoliosis is just one example. Often such advances are reported on by surgeons who are conflicted by personal and financial interests in the technology. This leads to all manner of potential bias–indication bias, reporting bias, selection bias, and detection bias to name just a few. Readers should evaluate this type of data with a high degree of suspicion.

What we need throughout orthopaedics are more multicenter, multisurgeon, “deconflicted” cohort studies and clinical trials. When such rigorous studies are conducted to investigate “high-tech” growing rods in patients with early-onset scoliosis, I will not be surprised if researchers find the same risk factors for reoperation after fusion that Du et al. found.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

Is It Safe to Drive After WALANT Hand Surgery?

Most everyone has seen the auto-insurance TV ad where the deep-voiced man asserts, “Safe drivers save 40%.” Insurance savings notwithstanding, patients frequently ask orthopaedic surgeons when they can return to safe driving after surgery. Of course, the answer depends partly on the patient’s ability to drive safely before surgery, but most of the orthopaedic research on this topic has focused on lower extremities. In the September 16, 2020 issue of The Journal, Orfield et al. take a detailed look at the driving question after wide-awake, local-anesthetic, no-tourniquet (WALANT) surgery of the hand.

Twelve right-handed patients drove 18 miles under baseline conditions and completed various parking tasks during the first 45- to 55-minute test. The instrumented vehicle they drove obtained kinematic data automatically, and behavioral responses were recorded on video cameras. Then the same subjects completed the same driving exercise in the same vehicle—but this time after having their right hand injected with 10 mL of 1% lidocaine over the volar wrist, and another 10 mL into the carpal tunnel. To further simulate WALANT conditions, researchers applied a bulky hand dressing to each participant’s right hand. The WALANT-modeled driving test included a simulated “surprise event” that required avoidance maneuvers. Researchers analyzed before-and-after data on a variety of kinematics, including braking, acceleration, right and left turning, and proportion of time spent driving with each or both hands.

Overall, Orfield et al. found no evidence of a negative impact on driving fitness in the simulated WALANT state. In fact, the subjects braked harder and steered more smoothly in the WALANT-modeled state, an indication that they perceived they might be impaired. Not surprisingly, participants in the WALANT-modeled state spent decreased time using both hands (from 72% to 62%), while left-hand-only driving increased from 2% to 16% of the time. All participants reported that they felt safe to drive with a numb, bandaged right hand.

These noninferiority findings suggests that WALANT patients are no worse off with immediate driving after the surgical procedure than they were beforehand. The authors are quick to point out that these findings should not be generalized beyond right-handed people driving a passenger car with an automatic transmission in the United States. Still, this study gives us some evidence-based data to better inform patients undergoing common hand procedures now frequently performed under WALANT conditions, such as trigger-finger and carpal-tunnel release. However, we can’t guarantee they will save on their auto insurance.

Click here to view a 3-minute “Author Insight” video with study co-author Peter J. Apel, MD, PhD.

Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media

Nontraumatic Osteonecrosis: An Early Target for Gene Therapy

As osteonecrosis of the femoral head (ONFH) progresses, it can impair a patient’s ability to walk, and hip arthroplasty is often the only effective long-term option. Other interventions to relieve the pain of ONFH include surgical decompression of the femoral head, which is generally effective but often does not change the natural history of the process. Once the femoral head collapses and loses sphericity, degenerative arthritis of the hip follows quickly. Well-documented risk factors for ONFH include excessive alcohol consumption and corticosteroid use. But why do some patients with these risk factors develop osteonecrosis, while others do not.

In the September 16, 2020 issue of The Journal, Zhang et al. address that clinical quandary with a genomewide association study on a chart-reviewed cohort of 118 patients with ONFH and >56,000 controls. The findings shed light on what is obviously a condition with multifactorial etiology and complex gene-environment interactions. The case-control study identified 1 gene (PPARGC1B) and 4 single nucleotide variants associated with ONFH overall, and with 2 subgroups—those exposed to corticosteroids and those with femoral head collapse. Steroid intake was highly prevalent in both cohorts—90.7% of the ONFH patients had at least one 3-week course of corticosteroids, compared with 68.3% of controls.

For readers interested in the detailed genetic bases for osteonecrosis, this study offers a treasure trove of data. But for all of us, these findings, after they are verified in other populations, may very well form the basis for pharmacologic and gene-modifying strategies in patients at risk for ONFH. Moreover, osteonecrosis of the femoral head is just one of many musculoskeletal conditions that can probably be addressed with this type of genome-based research strategy.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

What Affects Symptoms in Kids with Flatfoot?

Pes planovalgus (flatfoot) is a common condition seen in the pediatric orthopaedic clinic. We who help manage this condition differentiate it from adult acquired flatfoot deformity, primarily in that most child and adolescent patients remain asymptomatic or minimally symptomatic and rarely require surgical intervention. However, it would be nice to have data to share with young patients and their parents regarding factors associated with flatfoot symptoms.

Min et al. provide some of that data in the September 2, 2020 issue of The Journal. The authors retrospectively evaluated factors affecting the symptoms of idiopathic pes planovalgus among 123 patients (mean age of 10.1 ± 3.2 years) using the 4-domain Oxford Ankle Foot Questionnaire (OxAFQ) administered to patients and their parents. They compared questionnaire scores to 3 radiographic measurements─anteroposterior (AP) talo-first metatarsal angle, lateral talo-first metatarsal angle, and hallux valgus angles. They also analyzed the scores in relation to patient age and sex.

Min et al. found that the physical domain score for the child-reported OxAFQ decreased by 0.74 with each 1° increase in the AP talo-first metatarsal angle. Because that angle is a surrogate for forefoot abduction, this finding portends worse patient-reported outcomes in kids with greater severity of that component of flatfoot. Female sex was also associated with lower physical domain scores, with the authors postulating that this might be attributable to culturally influenced sex differences.

In addition, age was a significant factor in 3 domains of the OxAFQ. Compared with scores from younger kids, children ≥10 years old and their parents reported statistically worse outcomes with regard to school/play, emotional well-being, and footwear. In other words, at or beyond the age of 10, flatfoot deformity seems to significantly affect the patient’s choice of footwear, interferes with the ability to participate in sports and play, and may cause personal distress, such as that which comes from being teased about foot appearance.

Orthopaedists can help manage most cases of pediatric flatfoot with sound footwear recommendations and reassurance. But it appears that in the setting of increased forefoot abduction, female sex, and symptoms that persist past the age of 10 years, further investigation may be warranted. Although this study has weaknesses, it shows that there may be detriments─both physical and emotional─associated with pes planovalgus in pediatric patients that should not be ignored.

Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media