Comparison of Treatment Outcomes of Arthrodesis and Two Generations of Ankle Replacement Implants

Background: We analyzed self-reported outcomes in a prospective cohort of patients treated with ankle arthrodesis or total ankle replacement (TAR) during a time of transition from older to newer-generation TAR implants. Methods: We performed a prospective cohort study comparing outcomes in 273 consecutive patients treated for ankle arthritis with arthrodesis or TAR between 2005 and 2011. Adult patients with end-stage ankle arthritis who were able to walk and willing and able to respond to surveys were included in the study. Patients were excluded when they had another lower-limb problem that might affect walking. At baseline and at 6, 12, 24, and 36-month follow-up visits, participants completed a pain score, a Musculoskeletal Function Assessment (MFA), and a Short Form-36 (SF-36) survey. Results: There was significant mean improvement in most outcomes after surgery regardless of procedure. In general, the greatest improvement occurred during the first 6 months of follow-up. Linear mixed-effects regression adjusted for differences at baseline in age, body mass index (BMI), and surgery type showed that at 6 months the scores were improved by a mean (and standard error) of 12.6 +/- 0.7 (33%) on the MFA, 22.0 +/- 1.4 (56%) on the SF-36 Physical Functioning (PF) scale, 32.4 +/- 1.6 (93%) on the SF-36 Bodily Pain (BP) scale, and 4.0 +/- 0.2 (63%) on the pain rating scale. The mean improvements in the MFA and SF-36 PF scores over the 3-year follow-up period were significantly better after the TARs than after the arthrodeses, with differences between the 2 groups of 3.6 +/- 1.6 (p = 0.023) and 7.5 +/- 2.9 (p = 0.0098), respectively. The differences between the 2 groups were slightly greater when only the newer TAR devices were compared with the arthrodeses (MFA = 3.8 +/- 1.8 [p = 0.031], SF-36 PF = 8.8 +/- 3.3 [p = 0.0074], SF-36 BP = 7.3 +/- 3.6 [p = 0.045], and pain score = 0.8 +/- 0.4 [p = 0.038]). Conclusions: Patients reported improved comfort and function after both surgical treatments. The average improvement in the MFA and SF-36 PF scores was better after TAR than after arthrodesis, particularly when the TAR had been done with later-generation implants. Younger patients had greater functional improvements than older patients.