Background: The role of ankle arthroplasty in the treatment of ankle
arthritis is controversial. Ankle fusion is commonly performed, but there is
ongoing concern about functional limitations and arthritis in the adjacent
subtalar joint following ankle arthrodesis. The use of ankle arthroplasty as
an alternative to ankle fusion is expanding, but reported results have been
limited to those in case series. The purpose of this study was to compare the
reoperation rates following ankle arthrodesis and ankle replacement on the
basis of observational, population-based data from all inpatient admissions in
California over a ten-year period. Our hypothesis was that patients treated
with ankle replacement would have a lower risk of undergoing subtalar fusion
but a higher overall risk of undergoing major revision surgery.
Methods: We used California's hospital discharge database to
identify patients who had undergone ankle replacement or ankle arthrodesis as
inpatients in the years 1995 through 2004. Short-term outcomes, including
rates of major revision surgery, pulmonary embolism, amputation, and
infection, were examined. Long-term outcomes that were analyzed included the
rates of major revision surgery and subtalar joint fusion. Logistic and
proportional hazard regression models were used to estimate the impact of the
choice of ankle replacement or ankle fusion on the rates of adverse outcomes,
with adjustment for patient factors including age and comorbidity.
Results: A total of 4705 ankle fusions and 480 ankle replacements
were performed during the ten-year study period. Patients who had undergone
ankle replacement had an increased risk of device-related infection and of
having a major revision procedure. The rates of major revision surgery after
ankle replacement were 9% at one year and 23% at five years compared with 5%
and 11% following ankle arthrodesis. Patients treated with ankle arthrodesis
had a higher rate of subtalar fusion at five years postoperatively (2.8%) than
did those treated with ankle replacement (0.7%). Regression analysis confirmed
a significant increase in the risk of major revision surgery (hazard ratio,
1.93 [95% confidence interval, 1.50 to 2.49]; p < 0.001) but a decreased
risk of subtalar fusion (hazard ratio, 0.28 [95% confidence interval, 0.09 to
0.87]; p = 0.03) in patients treated with ankle replacement compared with
those treated with ankle fusion.
Conclusions: This study confirms that, compared with ankle fusion,
ankle replacement is associated with a higher risk of complications but also
potential advantages in terms of a decreased risk of the patient requiring
subtalar joint fusion. Additional controlled trials are needed to clarify the
appropriate indications for ankle arthrodesis and ankle replacement.
Level of Evidence: Therapeutic Level III. See
Instructions to Authors for a complete description of levels of evidence.