Natural Course of Long-Term Radiographic Indices in Primary Degenerative Ankle O.A

Category: Ankle Arthritis Introduction/Purpose: The prevalence of degenerative ankle arthritis is approximately 1% based on the population of patients visiting hospitals. When considering individuals with early-stage arthritis who may not exhibit any symptoms or only mild discomfort, this figure is likely even higher. Degenerative arthritis of the ankle, mainly secondary to fractures, is well-documented, while primary degenerative ankle arthritis is relatively rare, with limited reports on its etiology and natural course. However, in a disease like degenerative ankle arthritis, long-term follow-up of ten years or more is crucial, yet research on this subject remains scarce. This study analyzed the follow-up results of primary degenerative ankle O.A.(Takakura classification I,II,IIIA) patients without surgery for natural course. Methods: We retrospectively investigated 169 patients with degenerative arthritis who visited the hospital from May 2009 to November 2023. Among them, 32 patients, who did not undergo surgery and were followed up for a minimum of 10 years, underwent clinical and radiological examinations . Initial patients included those with Takakura classification stage IIIA or lower. The degree of Takakura classification stage change was compared between the first and final visits. Hindfoot views and whole lower extremity assessments were also conducted. Visual analogue scale (VAS), Foot Function Index (FFI) scale were measured, respectively. Results: Among the initial 169 patients, 32 patients(43 ankles) had completed ten years or more of follow-up. According to the Takakura classification, 5 ankles had no change in Stage I, while 1 ankle progressed to Stage II. In Stage II, 13 ankles had no change, and 2 ankles progressed to Stage IIIA. In Stage IIIA, 13 ankles showed no change, 7 ankles deteriorated to Stage IIIB, and 3 ankles progressed to Stage IV. Overall, out of 43 ankles, 31 remained unchanged, 10 deteriorated by one stage, and 2 deteriorated by two stages. At the initial visit and the final follow-up, the FFI scores were 57 and 51, VAS scores were 4.6 (1-9) and 3.5 (0-8). Conclusion: This study analyzed the long-term outcomes of patients with Takakura stage IIIA or lower degenerative ankle arthritis over a minimum of 10 years. The radiological progression was minimal, and most of cases were improvement in clinical pain and functional scores. Therefore, in primary degenerative arthritis of the ankle, it is essential to investigate whether ankle pain is due to arthritis then should be considered carefully in the surgical treatment of degenerative ankle arthritis.