Over the past decade, numerous investigations with favorable results of total ankle replacement (TAR) have questioned the position of open or arthroscopic ankle arthrodesis (OAA and AAA, respectively) as the gold standard surgical treatment for end-stage ankle arthritis1,2. Although the use of arthrodesis outpaces that of TAR, the gap is continually narrowing. An increase in the number of online resources dedicated to ankle arthritis, a growing enthusiasm for TAR, and a stigma associated with arthrodesis have prompted a greater number of patients to request ankle replacement. A combination of patients favoring TAR over arthrodesis and surgeons having increased interest in TAR has negatively influenced the ability to conduct high-quality research, rendering a prospective, randomized trial comparing the TAR and arthrodesis essentially unfeasible.
Nonetheless, the article by Veljkovic et al. provides an important comparison of TAR with OAA and AAA. Although the study is retrospective and nonrandomized, the prospectively collected data affords meaningful insight into the surgical treatment options for ankle arthritis. The investigators controlled for differences in the patient demographics through regression analysis. The preoperative Ankle Osteoarthritis Scale (AOS) total, pain, and disability scores were similar across the cohorts.
However, several biases and considerations are inherent in the study and warrant mention. The TAR group had the highest mean age, the greatest ratio of women to men, and the greatest percentage of patients with inflammatory arthropathy. The OAA and AAA cohorts had higher percentages of diabetic patients than the TAR cohort. The OAA group had the highest mean body mass index. The authors acknowledged that although the 6 surgeon-investigators had equal experience across all 3 procedures, some of them favored AAA or OAA over TAR. The investigators used a traditional crossed-screw technique for OAA and AAA; currently, many surgeons use anterior plating, a technique that may have the potential to improve outcomes for the OAA group. Appropriately, the authors limited the TAR cohort to a single prosthesis, the HINTEGRA (Integra LifeSciences), and although this implant has a long track record of satisfactory intermediate-term results in the hands of the inventor3, it is a mobile-bearing system that until June 2019 lacked U.S. Food and Drug Administration approval for implantation in the United States.
The study methodology was otherwise sound. For the full study cohort of 238 ankles in 229 patients, with 88 TARs, 50 AAAs and 100 OAAs, the preoperative characteristics of arthritis were reasonably uniform among all cohorts. With use of the Canadian Orthopaedic Foot and Ankle Society ankle arthritis classification system, the investigators limited the inclusion criteria to the simplest arthritis grade with minimal deformity and no evidence of adjacent hindfoot arthritis. The investigators utilized validated outcome measures that have been effectively applied to previous studies of the surgical treatment of ankle arthritis, including the AOS and the Short Form-364. Statistical analysis was performed by an investigator with dedicated training in statistics.
At a mean of 43.3 months and a minimum of 24 months, the intermediate-term results of this study provide important considerations for surgeons recommending TAR or arthrodesis. The investigators confirmed that across all cohorts, the Short Form-36 physical and mental component summary scores were similar preoperatively and at the latest follow-up, suggesting that favorable outcomes were observed irrespective of procedure performed. However, careful analysis suggests that the improvements in AOS total and disability scores were significantly greater for TAR and AAA compared with OAA. The investigators suggested that the larger surgical approach and potential for nerve irritation/injury may explain the less favorable OAA outcomes, but this suggestion does not account for TAR requiring an equally extensile exposure. This study supports previous investigations that identify reoperation being more common in TAR than arthrodesis, but also that reoperation without removal of the metal components does not constitute a failure of TAR. The overall rates of major revisions (i.e., metal component revision after TAR or repeat arthrodesis for nonunion after arthrodesis) were not significantly different among the 3 cohorts.
I commend the authors on this contribution to the orthopaedic literature and encourage them to continue to follow these patient cohorts. Long-term follow-up should demonstrate if substantial differences emerge among these procedures, creating symptoms that markedly affect patient-reported outcome measures. Especially important are (1) symptomatic component loosening and survivorship of the metal implants in TAR and (2) development or progression of symptomatic adjacent-joint hindfoot arthritis for TAR compared with OAA or AAA2.
1. Vakhshori V, Sabour AF, Alluri RK, Hatch GF 3rd, Tan EW. Patient and practice trends in total ankle replacement and tibiotalar arthrodesis in the United States from 2007 to 2013. J Am Acad Orthop Surg. 2019 Jan 15;27(2):e77-84.
2. Cody EA, Scott DJ, Easley ME. Total ankle arthroplasty: a critical analysis review. JBJS Rev. 2018 Aug;6(8):e8.
3. Barg A, Zwicky L, Knupp M, Henninger HB, Hintermann B. HINTEGRA total ankle replacement: survivorship analysis in 684 patients. J Bone Joint Surg Am. 2013 Jul 3;95(13):1175-83.
4. Liu G, Peterson AC, Wing K, Crump T, Younger A, Penner M, Veljkovic A, Foggin H, Sutherland JM. Validation of the Ankle Osteoarthritis Scale instrument for preoperative evaluation of end-stage ankle arthritis patients using item response theory. Foot Ankle Int. 2019 Apr;40(4):422-9. Epub 2019 Jan 10.