Total Ankle Arthroplasty for Post-Traumatic Fracture vs Primary Osteoarthritis: An Analysis of Complications, Revisions, and Implant Survival

Abstract

Category: Ankle Arthritis; Ankle Introduction/Purpose: Total ankle arthroplasty (TAA) has been shown to provide satisfactory clinical outcomes for the treatment of end-stage tibiotalar arthritis. However, most outcome studies do not discriminate by arthritis etiology, and there are currently no large-scale studies comparing outcomes of TAA performed for primary osteoarthritis (POA) versus post-traumatic osteoarthritis secondary to fracture sequelae (PTOA). The purpose of this study was to investigate the effect of arthritis etiology on post-operative complications, revision rates, and implant survival of TAA. Methods: 143 patients that underwent TAA for POA (n=68) and PTOA (n=75) between January 2014 and May 2021 were retrospectively evaluated. Surgeries were completed by a single fellowship-trained surgeon utilizing the same Stryker STAR implant for all cases. Patient demographics, postoperative complications, and revision surgery profiles were collected with a mean follow-up of 21 +- 19 months (Range 1.4 months-6.4 years). Based on a severity classification proposed by Gadd et al, complications were divided into low and high risk for TAA failure. Other complications (arthrofibrosis, impingement, periprosthetic cystic changes, Achilles tendinitis, persistent instability, and PTT dysfunction) were also collected. Logistic regression was used to analyze the relationship between patient demographics, osteoarthritis etiology, and complications. Categorical variables were compared with Chi-square tests, means with a two-tailed Student's t-test, and implant survival was assessed with a Kaplan-Meier analysis and Mantel-Cox logrank test. Significance was defined as p<.05 for all statistical analyses. Results: Cohort demographics were comparable except that POA patients were significantly older (65+-9 years) than PTOA patients (57+-13 years) (p<.001). There was no difference in rate of low risk (16.2% vs. 9.3%) (p=.218), high risk (13.2% vs. 16%) (p=.641), or other complications (14.7% vs 22.7%) (p=.224) between POA and PTOA. This remained true when controlling for patient demographics. At 7 years, TAA survival with implant retention revision as an endpoint was comparable between POA (91.2%) and PTOA (93.3%) (p=.615), with no difference in mean time to revision between POA (5+-4 months) and PTOA (16+-21 months) (p=.27). With TAA explant as an endpoint, greater survival trended in POA (100%) as compared to PTOA (94.6%) (p=.056) (Figure 1). Mean time to TAA explant for PTOA was 13+-7 months. Failure etiologies included symptomatic arthrofibrosis, component subsidence, periprosthetic fracture, and aseptic loosening. Conclusion: The complications, revision rates, and 7-year survivorship of TAA using a single prosthesis for PTOA secondary to fracture sequelae were no different when compared to TAA for POA. However, there was a non-significant trend for an increased rate of implant failure requiring TAA explant in PTOA compared to POA (Figure 1). Given this trend, further investigation is warranted to assess the long-term outcomes and implant survival of total ankle arthroplasty for post-traumatic fracture osteoarthritis.