SLR - April 2019 - Jason Spector

The Effect of Patient Characteristics on One to Two-Year and Minimum Five-Year Outcomes After Total Ankle Arthroplasty

Reference: Cunningham DJ, DeOrio JK, Nunley JA, Easley ME, Adams SB. The effect of patient characteristics on one- to two-year and minimum five-year outcomes after total ankle arthroplasty. J Bone Joint Surg Am. 2019 Feb 6; 101(3): 199–208.

Scientific Literature Review

Reviewed By: Jason Spector, DPM
Residency Program: Northwest Medical Center, Margate, FL

Podiatric Relevance: Total ankle arthroplasty (TAA) has become a viable alternative to ankle arthrodesis, especially in patients with end-stage ankle arthritis. Patient selection and comorbidities are key aspects when considering this surgical intervention. These factors not only affect patient outcomes, but also implant durability. Previous studies have identified risk factors perioperatively and their impact on postoperative outcomes. The authors in this paper sought to evaluate a cohort of patients undergoing TAA and the impact of common comorbidities and patient factors on patient-reported outcomes. The results of this investigation may help surgeons identify and further refine their criteria for patients undergoing TAA.

Methods: This paper was a retrospective review from a board-approved, single-center, prospective, observational study of patients who underwent TAA in an approximate 10-year span. All patients undergoing TAA were eligible for the study. Data collection included age, sex, race, BMI, ASA class, current smoking status and prior ipsilateral ankle procedures. Elixhauser and Charlson-Deyo comorbidities (consolidation of comorbidities into predictive values measuring outcomes, such as mortality) were recorded and updated. These specifically could predict length of stay, hospital charges, hospital mortality and one-year mortality. In addition, SF-36, VAS and SMFA were recorded pre- and postoperatively. Patient comorbidities with at least 10 percent prevalence in the overall study population were analyzed. These factors were then assessed for association with outcome measures in a multivariable linear regression model. A final multivariable model was created for each outcome that included both baseline/operative factors and significant individual comorbidities.

Results: There were 688 patients that fulfilled one- to two-year follow-up criteria. All outcomes showed significant improvement with patients’ pain and function. In particular, greater preoperative pain and/or disability correlated to greater change in outcome score. Factors that were significantly associated with smaller improvements in outcomes included depression, smoking, increased ASA class, staged bilateral procedure, prior ipsilateral ankle surgical procedure, implant type and increased length of stay. Modeling data was again computed for patients at minimum five-year follow-up (187 patients), showing similar trends. Interestingly, obesity was associated with improvement to pain relief.

Conclusions: This study demonstrates several novel points. A negative impact on patient outcomes with TAA was found with depression, increased ASA class, increased length of stay and prior surgical procedure. These factors have not been reported in prior literature as significant links to reduced improvement after TAA. In contrast, obesity was reported to be associated with improved pain relief at their five-year follow-up. Although there may be concern about implant durability, this is the first report demonstrating improved patient outcomes. Additionally, there was no significant impact of either diabetes or age on patient outcomes. In conclusion, the authors reported substantial improvement in patient-reported outcomes following TAA surgery. They extrapolated several factors (small but significant) that had a negative impact on outcomes, including depression, increased ASA class, current smoking, increased length of stay, a prior surgical procedure and staged bilateral TAA. The results of this study may provide a foundation for surgeons to further refine their criteria and identify patients who are eligible for TAA.

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