After some relatively poor results in the 1980s, there was a “reboot” with total ankle arthroplasty (TAA) in the late 1990s to improve outcomes so that TAA would provide a reliable treatment for patients with end-stage ankle arthritis. Advances in the understanding of the biomechanical requirements for ankle prostheses and which patients might benefit from them the most—plus the realization that TAA is a technically demanding surgical procedure that requires advanced education—have vastly improved the outcomes of these procedures. In fact, TAA has become reliable enough that we can now begin to tease out the patient variables that seem to affect outcomes.
In the February 6, 2019 issue of The Journal, Cunningham et al. use an extensive clinical TAA registry to identify patient characteristics that impact TAA outcomes. The good news is that, 30-plus years after the inauspicious outcomes of first-generation TAA, overall pain and function significantly improved among the patients in this study. However, current smoking was associated with poorer patient outcomes at the 5-year follow-up, as it seems to be with the vast majority of orthopaedic procedures. Also, at a mean 1- to 2-year follow-up, a previous surgical procedure on the ankle was associated with significantly smaller improvements in at least 1 patient-reported outcome. This makes sense because prior surgery leads to scarring and its attendant risk of infection and increased difficulty with exposure and the ideal placement of TAA components. Cunningham et al. also identified depression as being associated with worse TAA outcomes at all follow-up points, adding to our already ample body of evidence that patient psychological factors play a major role in orthopaedic surgical results.
Interestingly, these authors found that patients undergoing staged bilateral ankle arthroplasty did not do as well as those undergoing simultaneous bilateral TAAs. And somewhat surprisingly, the authors found obesity to be associated with better outcomes at the 5-year follow-up. This may be related to increased bone density and greater soft-tissue coverage, but this finding is still seemingly counterintuitive based on everything else we know about the negative associations between obesity and outcomes of other joint replacements.
As more surgeons and orthopaedic centers make use of TAA, it will be important for us to follow the lead of the total knee and total hip communities in providing large datasets to further clarify which factors—patient-related and surgical—lead to the best and worst patient outcomes. This study by Cunningham et al. provides a starting point upon which other research will hopefully build.
Marc Swiontkowski, MD
Here’s one thing about which medical studies have been nearly unanimous: Smoking is a health hazard by any measure. In the February 15, 2017 edition of The Journal of Bone & Joint Surgery, Tischler et al. put some hard numbers on the risk of smoking for those undergoing total joint arthroplasty (TJA).
After controlling for confounding factors, the authors of the Level III prognostic study found that:
- Current smokers have a significantly increased risk of reoperation for infection within 90 days of TJA compared with nonsmokers.
- The amount one has smoked, regardless of current smoking status, significantly contributed to increased risk of unplanned nonoperative readmission.
In a commentary on the Tischler et al. study, William, G. Hamilton, MD says, “…as physicians, we should work cooperatively with our patients to enhance outcomes by attempting to reduce these modifiable risk factors. We can educate patients and can suggest smoking cessation programs and weight loss regimens that may not only improve the risk profile during the surgical episode, but also improve the patients’ overall health.”
Researchers at Vanderbilt University Medical Center have concluded that fibrin, a protein involved in blood clotting and found abundantly around the site of new bone fractures, impedes rather than supports fracture healing.
Their recent study in The Journal of Clinical Investigation looked at mice that had experimentally induced deficits in either fibrin production or fibrin clearance. Researchers found normal fracture repair in mice without fibrin and impaired vascularization and fracture healing in mice with inhibited fibrin clearance. They also saw increased heterotopic ossification in the mice unable to remove fibrin.
In a Vanderbilt press release, study coauthor Jonathan Schoenecker, MD, commented that “any condition associated with vascular disease and thrombosis will impair fracture healing.” These findings, he suggested, may explain why obesity, diabetes, smoking, and old age—all of which are associated with impaired fibrin clearance—are also associated with impaired fracture healing. Dr. Schoenecker went on to speculate that anti-clotting drugs commonly used to treat cardiovascular conditions may find new applications in enhancing fracture repair.
The July 1, 2015 JBJS contains a database-driven analysis by Duchman et al. of more than 78,000 patients who underwent primary total hip or knee arthroplasty between 2006 and 2012. The authors found that the 10% who were current smokers had a higher rate of wound complications (1.8%), compared with rates in former smokers (1.3%) and nonsmokers (1.1%). Current smokers had approximately twice the rate of deep wound infections compared with former smokers or nonsmokers. The authors note, however, that periprosthetic infections—a specific complication of great interest to orthopaedists and patients—are not captured by the National Surgical Quality Improvement Program (NSQIP) database from which the analyzed data was extracted.
These findings align with several others that associate smoking with short-term postsurgical complications. However, commentators Jeffrey Cherian, DO and Michael Mont, MD note that this study’s definitions of “current” smokers (those who smoked within one year of surgery) and “former” smokers (those who did not smoke in the year prior to surgery but did smoke a pack a day or more for at least a year before that) leave surgeons “unable to adequately define a time point at which smoking should be stopped prior to surgery…to decrease the risk of adverse outcomes.” The commentators call for trials that more strictly stratify patients by tobacco usage so that surgeons can “evaluate the optimal time point for smoking cessation as well as the best programs and options for nicotine replacement.”