Long term consequences of Total Ankle Replacement versus Ankle Fusion; a 25 year national population study of 41,000 patients

Aims

Definitive and successful treatment of end stage ankle arthritis is either Total Ankle Replacement (TAR) or Ankle Fusion (AF). Both options place patients on an irreversible pathway that risks harm from further surgery. AF may predispose patients to subsequent hindfoot joint fusion and TAR is associated with high rates of complex revision surgery. The aim is to improve decision making by investigating the risks of further surgery, adjacent joint surgery and rare but serious complications of AF versus TAR.

Methods

An England population cohort study was performed using the Hospital Episode Statistics database, linked to ONS mortality data (19982023). The primary outcome was Kaplan Meier curve analysis of revision surgery free survival of TAR versus AF. Secondary outcome measures were the rates of adjacent joint/hindfoot fusion, any further reintervention to the ankle, perioperative mortality, 90 day complications, and serious adverse events.

Results

10,335 TAR and 30,704 AF were analysed. The AF revision rate was significantly lower than TAR at all time points including; 5 years (2% vs 6.1%, RR 0.12; 95% CI 0.10 to 0.16), 10 years (2.5% vs 10.2%, RR 0.12; 95% CI 0.08 to 0.18) and 20 years (3.1% vs 13.55%, RR 0.12; 95% CI 0.01 to 0.23).

There was no significant difference in 25 year risk of adjacent joint fusion following AF (8.64%, 95% CI 7.79% to 9.58%) versus TAR (6.82%; 95% CI 5.36% to 8.66%). TAR was associated with higher risks of intra operative fracture (0.42% vs 0.10%, RR = 4.35) and reintervention for wound infection (0.26% vs 0.15%, RR 1.74) but fewer pulmonary emboli (0.23% vs 0.58%, RR = 0.40).

Conclusion

Both TAR and AF are safe definitive treatments of ankle arthritis with low perioperative risk. TAR is associated with a significantly higher rate of further revision surgery than AF. AF does not predispose patients to hindfoot fusion surgery.