Super-Slippery Device Coating Prevents Blood Clots and Bacterial Adhesion

Whenever physicians implant a “foreign” device in the body, as orthopaedists often do, the implant is up against two crucial challenges: blood clots and bacteria. Solving both of those challenges took a big step forward with the recent publication in Nature Biotechnology of results with a new device-surface coating that thwarts blood clotting and keeps certain bacteria from sticking to it through glycocalyx formation. The repellant coating, called tethered-liquid perfluorocarbon, or TLP, is a modified version of the super-slippery stuff that the carnivorous pitcher plant uses to catch insects.

Harvard researchers tested the coating, the two constituents of which are already FDA-approved, in vitro on 20 different medical surfaces, including glass and metal, where it suppressed platelet adhesion and activation under simulated blood flow. They also tested it in vivo with catheters implanted into the large veins of pigs, where it prevented blood clotting for eight hours without the use of anticoagulants. In another in vitro experiment during which TLP-coated medical tubing was exposed to Pseudomonas aeruginosa for six weeks, only one in a billion of the bacteria were able to adhere.

It’s too early to say with certainty if and when TLP coatings might be ready for use on orthopaedic implants, but the approach raises hopes that a powerful new preventer of two major complications associated with orthopaedic device implantation is feasible in the near future.

JBJS Classics: ACL Graft Strength and Stiffness

Each month during the coming year, OrthoBuzz will bring you a current commentary on a “classic” article from The Journal of Bone & Joint Surgery. These articles have been selected by the Editor-in-Chief and Deputy Editors of The Journal because of their long-standing significance to the orthopaedic community and the many citations they receive in the literature. Our OrthoBuzz commentators will highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation about these classics by writing in the “Leave a Reply” box at the bottom of the page.

In the classic article, “Biomechanical analysis of human ligament grafts used in knee-ligament repairs and reconstructions” (J Bone Joint Surg Am 1984; 66:344–352), now 30 years old, Noyes and colleagues studied the mechanical properties of several anterior cruciate ligament (ACL) grafts that were used at that time. Using young donors, they found that the bone-patellar tendon-bone (BPTB) graft was the only graft studied that had a maximum load in excess of the native ACL. Many of the grafts they studied—including iliotibial tract, fascia lata, and quadriceps retinaculum—had exceedingly poor strengths, which is probably why they are no longer used.

Unfortunately, the authors did not double their hamstring grafts (as is commonly done clinically) for testing, and they also used 14-mm BPTB grafts, which are much wider than commonly used clinically, so some of their comparisons may have limited clinical applicability. The authors did note several limitations to their study, including that graft strength is only one of many factors for successful ACL reconstruction, that gripping was sometimes a problem during testing, and that they only performed uni-axial testing. Nevertheless, this article set the stage for critically analyzing graft choice based upon mechanical properties.

Subsequent studies, including those by Woo, Cooper, Howell, Brown, and others, now suggest that several grafts are available that are stronger and stiffer than the native ACL, including BPTB, quadrupled hamstring (strongest and stiffest of all grafts studied), quadriceps tendon, tibialis anterior tendon, and posterior tibial tendon:

Graft Type Ultimate Strength(N) Stiffness (KN/m)
Native ACL 2160 292
BPTB 2977 620
Quadrupled Hamstring 4590 861
Quadriceps Tendon 2352 463
Tibialis Anterior 3412 344
Posterior Tibialis 3391 302

 

Of course, many other ACL reconstruction controversies continue to be debated, including technique, fixation, and autograft vs. allograft. But graft strength and stiffness will continue to be one of many important factors for the ACL surgeon to consider, especially if future options such as ACL augmentation and the use of synthetics and biologics become available. We welcome comments from JBJS readers.

Mark D. Miller, MD

JBJS Deputy Editor for Sports Medicine

JBJS/JOSPT Joint Webinar: Return to Sports after ACL Reconstruction

“When will I be able to play again?” Following ACL reconstruction surgery, that’s a question orthopaedic surgeons and physical therapists invariably hear—often repeatedly—from their athletically inclined patients.

The multiple surgical, rehabilitative, and patient-centered factors that go into answering this difficult question are the subject of this free webinar, hosted jointly by The Journal of Bone and Joint Surgery (JBJS) and the Journal of Orthopaedic & Sports Physical Therapy (JOSPT).

This webinar will focus on the following two articles, one from each journal:

•      Operative Treatment of Primary ACL Rupture in Adults (JBJS 2014; 96:685-94)
•      Return to Preinjury Sports Participation Following ACL Reconstruction: Contributions of Demographic, Knee Impairment, and Self-report                     Measures (JOSPT 2012; 42:893-901)
After the articles’ primary authors present their data, two additional return-to-sports experts will add their perspectives to this body of research. The audience will have the opportunity to ask questions of the presenters.

Sign up for the November 12th webinar today!

 

Answers to FAQs on Orthopaedic Coding

AAOS Now answers commonly asked coding questions for orthopaedic practices. This month’s column by Mary LeGrand, RN, senior consultant with KarenZupko & Associates, specifically addresses the following thorny coding issues in a Q&A format:

  • Coflex interlaminar technology
  • Modifier 51 or 59 in relation to intra-articular injections
  • Open surgery for femoroacetabular impingement (FAI) syndrome
  • Diskectomy and stenosis procedures
  • ACL reconstruction

Use of Google Glass with EHRs Expanding

Google Glass is expanding its medical applications far beyond capturing and transmitting videos of surgery. Google Glass is now entering and retrieving patient information into and from electronic health records. A pilot test of Google Glass and Augmedix taking place at Dignity Health’s Ventura Medical Clinic involves three family practices and over 2,700 patients. Physicians using Google Glass have reported a major drop in daily time spent entering info into the EHR from 33% to 9% and an increase in direct patient care time from 35% to 70%. Participating doctors put on Google Glass prior to meeting with the patient. During the visit, Augmedix software captures the audio and video through the device and enters it into the EHR system. The doctor can also ask questions to retrieve certain types of information such as lab-test results. (See related OrthoBuzz item from May 2, 2014.)

Bidding on Medical Services Raises Quality, Ethical Concerns

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?”

Doctor Shopping for Narcotics Common among Trauma Patients

A study in the August 6, 2014 JBJS revealed that the prevalence of postoperative “doctor shopping” among a cohort of 130 orthopaedic trauma patients in Tennessee was a surprisingly high 20.8%. This study used the state-controlled substance monitoring database to identify the narcotic prescriptions filled by patients three months prior to surgery and up to six months after discharge. The study segmented the test group into those who received prescriptions only from the treating surgeon or healthcare extender and those who got prescriptions from multiple doctors and extenders.

According to the study, patients who doctor shopped received an average of seven prescriptions for narcotics compared to an average of two prescriptions among those who got prescriptions from a single provider. Those with a high-school education or less were three times more likely to seek out multiple providers. According to Dr. Douglas Lundy, a spokesperson for the American Academy of Orthopedic Surgeons, “I think what the study tells us is there is a subgroup of patients you need to be a little more vigilant on, that they may be taking more drugs than you think they’re taking.”

Editor’s Choice—JBJS Reviews, October 2014

Technological advances in orthopaedic surgery occur steadily and incrementally. However, every so often, something comes along that really changes orthopaedic practice. Such is the case with the introduction of reverse shoulder arthroplasty, which is a unique, novel procedure that can be used to treat a variety of conditions affecting the shoulder. In this month’s issue of JBJS Reviews, George et al. review the use of reverse shoulder arthroplasty for the treatment of proximal humeral fractures.

Proximal humeral fractures, particularly those that occur in osteoporotic bone, can be complex and difficult to manage. While the majority of these fractures can be successfully treated with initial mobilization in a sling followed by return to activities, three and four-part fractures often are associated with poor functional outcomes, including nonunion, malunion, posttraumatic glenohumeral arthritis, and stiffness. Thus, operative interventions such as closed reduction and percutaneous pinning, open reduction and internal fixation with locked or unlocked plates, and locked intramedullary nailing are available options. However, because of the difficulty associated with reduction of three and four-part fractures, open reduction and internal fixation is associated with a high rate of complications.

Nearly sixty years ago, Neer described the use of hemiarthroplasty for the treatment of three and four-part fractures of the proximal part of the humerus. Implants and techniques steadily improved over the ensuing six decades, but the introduction of reverse shoulder arthroplasty may represent a major step forward. In the article by George et al., the use of reverse shoulder arthroplasty for the treatment of complex fractures of the proximal part of the humerus appears to have led to good results after short and intermediate-term follow up. Malunion or nonunion of the tuberosities did not affect the functional result after reverse total shoulder arthroplasty as much as it did after hemi-arthroplasty, but it did lead to decreased postoperative external rotation.

The long-term outcomes of reverse shoulder arthroplasty for the treatment of these fractures still have not been well established, so we probably should not rush to change our practice on the basis of this article alone. Indeed, since the results have been shown to deteriorate as early as six years postoperatively, reverse shoulder arthroplasty should be reserved for older patients and should be avoided in younger patients. Reverse shoulder arthroplasty can be used for the treatment of rotator cuff arthroplasty and recently has gained popularity for the treatment of severe proximal humeral fractures. This article provides a thorough yet concise overview of the application of this novel technique and implant to the treatment of these difficult and complex injuries.

Thomas A. Einhorn, MD, Editor

Active Immune Cells Associated with Quick Recovery from Hip Replacement

The signaling activity of CD14+ monocytes after hip replacement surgery in 32 patients correlated strongly with the patients’ reports of postsurgical pain and function. Stanford researchers reporting in the September 24, 2014 Science Translational Medicine exposed pre- and postsurgical blood samples from the 32 patients to mass cytometry and discovered that people whose CD14+ cells were highly active in specific ways after the operation recovered faster than those whose cells showed low activity.

The current findings can’t be used to predict prior to surgery which individuals will recover quickly or slowly, because the postsurgical CD14+ activity that correlated with clinical outcomes was present only after surgery. But further research on larger numbers of people could lead to “diagnostic signatures” to help predict individual recovery times and to therapeutic targets for improving patient recovery overall.

Nonoperative Knee-Pain Treatments: Acupuncture—No, Bracing—Yes

Two recent studies revealed that valgus bracing may be more effective than acupuncture for treating knee osteoarthritis.

A JAMA study of nearly 300 people 50 and older with chronic knee pain and morning stiffness found that 12 weeks of acupuncture, delivered via both needles and laser,  provided no substantial pain or function benefits at 12 weeks or one year, relative to no acupuncture or a sham laser procedure. One interesting aspect of this study was its so-called Zelen design; participants were consented after randomization, and those randomized to receive no acupuncture were unaware that they were in an acupuncture trial. According to the authors, “Zelen designs can reduce the risk of bias in a treatment trial in which knowledge of the intervention may influence recruitment…and outcomes.”

Conversely, a meta-analysis of six randomized studies totaling more than 400 patients in Arthritis Care and Research found that a valgus knee brace can improve pain and function in people with medial knee osteoarthritis. The analysis examined trials that compared valgus bracing with no orthosis and with other types of orthoses, such as neoprene sleeves. In the former comparison, the valgus brace yielded improvements in both pain and function; in the latter comparison, valgus bracing improved pain but not function. An editorialist commenting on the findings opined that the clinical goal going forward should be to identify those patients who are most likely to benefit from this type of bracing and who will comply with instructions for use.

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