Is total replacement of the ankle an option?

There is increasing interest in total ankle replacement (TAR) as an alternative to arthrodesis in the treatment of end-stage ankle arthritis. Despite a lack of long-term data on the clinical outcomes associated with ankle implants, the use of TAR is expanding.

For decades, the painful ankle has been successfully treated with arthrodesis. The method is well documented in a number of reports, many of them just reporting the rate of radiographic and/ or clinical healing, but some of these reports have also assessed the functional outcome. The surgical technique varies, from percutaneous in ankles with symmetrical bone loss (Lauge-Pedersen et al. 1998) to open with screw fixation (high rate of healing in non-rheumatic ankles) (Andersson et al. 2005a). External fixation still has some advocates, but retrograde intramedullary nailing seems to be one of the safest options (Andersson et al. 2005b). Radiographic osseous healing is not always achieved—but the more hardware that is used, the more probable it is that the patient will be relieved from pain in spite of that. Should symptomatic nonunion occur, it may be treated successfully by primary or repeated retrograde nailing. This implies sacrifice of the talocalcaneal joint, which is already arthritic in many patients and perhaps also a source of pain.

The advantage of ankle arthrodesis is that correction of deformity and relief of pain commonly result in improved walking ability, even in the presence of some arthritic joints in the hind- or midfoot. Pre-existing arthritic or degenerative lesions in the hind- and midfoot will, however, inevitably deteriorate after ankle fusion—and there is a definite risk of secondary osteoarthritis in the midfoot in the long run. The change in loading of the midfoot after tibiotalar fusion (in an experimental setting) is described by Suckel et al. (2007) in this issue of Acta Orthopaedica. Arthrodesis of the subtalar joints in this situation results in a mechanically dif- ficult situation. Another problem is the increased stress put on an ipsilateral disabled or replaced knee and/or hip caused by an immobile ankle joint. Correct positioning of the joint is important and— technically—sometimes difficult to obtain.