The incidence of periprosthetic fractures of
the ankle is increasing. However, little is known about the outcome
of treatment and their management remains controversial. The aim
of this study was to assess the impact of periprosthetic fractures
on the functional and radiological outcome of patients with a total
ankle arthroplasty (TAA). A total of 505 TAAs (488 patients) who underwent TAA were retrospectively
evaluated for periprosthetic ankle fracture: these were then classified
according to a recent classification which is orientated towards
treatment. The outcome was evaluated clinically using the American
Orthopedic Foot and Ankle Society (AOFAS) score and a visual analogue
scale for pain, and radiologically. A total of 21 patients with a periprosthetic fracture of the
ankle were identified. There were 13 women and eight men. The mean
age of the patients was 63 years (48 to 74). Thus, the incidence
of fracture was 4.17%. There were 11 intra-operative and ten post-operative fractures,
of which eight were stress fractures and two were traumatic. The
prosthesis was stable in all patients. Five stress fractures were
treated conservatively and the remaining three were treated operatively. A total of 17 patients (81%) were examined clinically and radiologically
at a mean follow-up of 53.5 months (12 to 112). The mean AOFAS score
at follow-up was 79.5 (21 to 100). The mean AOFAS score in those
with an intra-operative fracture was 87.6 (80 to 100) and for those
with a stress fracture, which were mainly because of varus malpositioning,
was 67.3 (21 to 93). Periprosthetic fractures of the ankle do not
necessarily adversely affect the clinical outcome, provided that
a treatment algorithm is implemented with the help of a new classification
system. Cite this article:
We report the clinical and radiological outcome of total ankle replacement performed in conjunction with hindfoot fusion or in isolation. Between May 2003 and June 2008, 60 ankles were treated with total ankle replacement with either subtalar or triple fusion, and the results were compared with a control group of 288 ankles treated with total ankle replacement alone. After the mean follow-up of 39.5 months (12 to 73), the ankles with hindfoot fusion showed significant improvement in the mean visual analogue score for pain (p <
0.001), the mean American Orthopaedic Foot and Ankle Society score (p <
0.001), and the mean of a modified version of this score (p <
0.001). The mean visual analogue pain score (p = 0.304) and mean modified American Orthopaedic Foot and Ankle Society score (p = 0.119) were not significantly different between the hindfoot fusion and the control groups. However, the hindfoot fusion group had a significantly lower mean range of movement (p = 0.009) and a higher rate of posterior focal osteolysis (p = 0.04). Both groups showed various complications (p = 0.131) and failure occurring at a similar rate (p = 0.685). Subtalar or triple fusion is feasible and has minimal adverse effects on ankles treated with total ankle replacement up to midterm follow-up. The clinical outcome of total ankle replacement when combined with hindfoot fusion is comparable to that of ankle replacement alone. Thus, hindfoot fusion should be performed in conjunction with total ankle replacement when indicated.
