ICJR REWIND: Busting Myths about Postop Management of TJA Patients
With his kids providing inspiration through their love of the television show Myth Busters, James A. Browne, MD, has taken a scientific approach to evaluating various practices followed in the postoperative period and determining if they are myths, plausible but need more evidence, or confirmed.
He shared his conclusions at ICJR’s 10th Annual Winter Hip & Knee Course during a session on urban legends in total joint arthroplasty.
Dr. Browne, from the University of Virginia in Charlottesville, addressed these issues:
- Continuous passive motion
- Dressing changes
- Mechanical deep vein thrombosis prophylaxis
- Flying after surgery
- Dental prophylaxis
What did he find? Only mechanical DVT prophylaxis has been confirmed through high-quality evidence, while more research is needed on cryotherapy and dental prophylaxis. Continuous passive motion, dressing changes, flying after surgery – they’re myths he has busted through his review of the literature.
The urban legend: Local application of cold reduces edema, minimizes tissue damage, and ameliorates pain.
A systematic review by Ni et al  looked at 10 randomized controlled trials (RCT) comprising 660 total knee arthroplasties (TKA) and found that cryotherapy appeared to decrease blood loss, but not the rate of blood transfusion. Cryotherapy also decreased pain on post-operative day 2.
The Cochrane group in 2012 reviewed data that suggested patients who had received cryotherapy had slightly higher flexion (approximately 11°) at time of discharge and concluded: “Potential benefits may be too small to justify its use, and the quality of the evidence was very low or low for all main outcomes. This needs to be balanced against potential inconveniences and expenses of using cryotherapy.”  Other prospective, randomized studies have consistently shown little or no difference in long-term range of motion (ROM).
The surgical guidelines published by the American Academy of Orthopaedic Surgeons (AAOS) in 2015 made this recommendation: “Moderate evidence supports that cryotherapy devices after knee arthroplasty do not improve outcomes.”
However, Dr. Browne said, cryotherapy is reasonably inexpensive and convenient, and “we all have patients who swear cryotherapy helps them more than oxycodone.”
Dr. Browne declared the myth of cryotherapy to be “plausible.”
Continuous Passive Motion (CPM)
The urban legend: Early postoperative knee motion improves outcomes.
The concept of early movement is approximately 100 years old. When looking specifically at the knee, Dr. Robert Salter invented the concept of CPM in the 1970s based on animal studies from the 1960s. Dr. Salter compared knee joint injuries in rabbits and found significantly less inflammation in joints randomized to motion versus those that had been in a cast. These findings were extrapolated to mean CPM would be beneficial to TKA patients as well.
The arguments against CPM are increased pain and bleeding risk. CPM adds cost and interferes with mobility and nursing, and shared machines may increase infection risk.
A Cochrane study from 2014 found a 2° short-term increase in ROM in the first 6 weeks after surgery . Although the data may be statistically significant, are they clinically meaningful? Dr. Browne said that medium and long-term data from the same study found no difference in ROM.
Most clinical studies have failed to find any other benefits to CPM, and the AAOS Surgical Guidelines from 2015 concluded: “The strong evidence indicated that no further research is needed on the routine use of continuous passive motion after total knee arthroplasty, but there are patients who are at significant risk of postoperative stiffness, for whom additional studies are appropriate.”
Dr. Browne declared the myth of CPM to be “busted.”
The urban legend: Don’t touch the dressings for 48 hours after total joint arthroplasty. Then perform daily dressing changes with gauze to keep the wound dry and monitor healing.
Dressing changes are all about exudate management, Dr. Browne said. Exudate is produced during the inflammatory phase of healing and facilitates movement of cytokines, growth factors, and white blood cells. The moisture provides autolytic debridement and prevents dehydration. However, excessive exudate can cause maceration of the skin.
A Cochrane systematic review from 2015 looked 4 RCTs comparing early (within 48 hours) and late dressing removal and found no differences with regard to wound complications or infections.  Early removal of dressings, therefore, does not appear to have a detrimental effect on outcomes Dr. Browne said.
Daily dressing changes have the potential to infect the wound as well as cause blistering, skin irritation, and pain associated with tapes and adhesives. Episodic cooling of the wound may also interrupt cellular activity. 
An RCT study from 2015 by Springer et al  compared Aquacel dressings left on for 7 days with Primapore dressings changed at 2 days, and then every other day and as needed. The study concluded that if the dressing is changed often, the patients get more blisters, and the superficial surgical site infection may be slightly higher. Leaving a non-occlusive dressing on for 7 days resulted in less drainage and fewer wound complications (10% vs 22%), fewer blisters (0.7% vs 6%), and greater patient satisfaction in personal hygiene, changing clothes, and sitting and sleeping comfort.
Dr. Browne declared the dressing change myth to be “busted.”
Mechanical Venous Thromboembolism Event (VTE) Prophylaxis
The urban legend: Non-pharmacologic interventions (stockings, early mobilization, avoiding tourniquet) can reduce the incidence of VTE.
A 2010 Cochrane Systematic Review included 18 RCTs involving gradual compression stockings (GCS) found 13% deep vein thrombosis (DVT) with GCS versus 26% in the control group.  These results get even better if GCS is combined with chemoprophylaxis. The American College of Clinical Pharmacy similarly found a decrease in DVT; however, GCS cause a 10-fold increase in skin complications.
Intermittent pneumatic devices have been found to decrease the relative risk of DVT by more than 50%. However, patient compliance is an issue.
Retrospective studies have consistently shown benefit to early mobilization. A 2007 study by Pearse et al  showed a 30-fold reduction in DVT when patients were mobilized early. A 2009 study by Chandrasekaran et al  found DVT risk correlated with the distance walked in the first 24 hours after surgery. Systematic reviews have found no increase in DVT risk when tourniquet is used. 
Dr. Browne declared the mechanical VTE prophylaxis myth “confirmed.”
Flying after TKA
The urban legend: Patients should not fly for 12 weeks after TKA due to the risk of VTE.
Dr. Browne reviewed the evidence of VTE risk when traveling, as summarized in a 2011 study published in the British Journal of Heamatology.  There is really no difference between flying and driving long distances, Dr. Browne said. It is an issue of mobility. The study found a 2- to 4-fold relative risk of DVT with travel, with longer flights having the highest risk.
The Centers for Disease Control and Prevention lists “recent surgery within 3 months” as a risk factor for travel-related thrombosis but provides no actual evidence to support this statement. Limited evidence suggests that high-risk patients undertaking journeys longer than 3 hours should wear compression stockings.
The only retrospective study to review VTE risk after total joint arthroplasty associated with flying  used aspirin for VTE prophylaxis in 96% of patients and found no difference in rates of DVT, pulmonary embolism, or overall VTE.
Dr. Browne declared the flying after TKA myth to be “busted.”
In his practice Dr. Browne tells his patients that there is no compelling evidence to restrict flying after TKA, especially for short to medium flights. The increased risk – if it exists at all – is likely to be low, especially if reasonable precautions are taken, such as chemoprophylaxis, GCS, and mobilization every hour.
The urban legend: Patients with prosthetic joints need antibiotics before dental work for the rest of their lives.
This legend is a tricky one, Dr. Browne said. The first advisory statement from the AAOS and American Dental Association (ADA) in 1997 said that dental prophylaxis – with some exceptions – is “not routinely indicated.” This was reaffirmed in 2003. However, the 2009 AAOS Patient Safety Committee Opinion Statement was a major departure stating that all patients should receive dental prophylaxis for their lifetime.
The 2012 AAOS/ADA Evidence Based Guidelines found evidence that dental work can cause bacteremia and that dental prophylaxis can reduce bacteremia, but there is no evidence that dental bacteremia can result in periprosthetic joint infection.
In his practice, Dr. Browne recommends that low-risk patients continue dental prophylaxis up to 2 years after surgery, and after that it is up to the patient whether they continue prophylaxis or not. For high-risk patients, lifetime prophylaxis is recommended.
Dr. Browne found no good evidence to support or refute the dental prophylaxis myth and declared that “more evidence is needed.”
Click the image above to watch the presentation by Dr. Browne.
This article was originally published on August 30, 2018.
Disclosures: Dr. Browne has no disclosures relevant to this presentation.
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