Long term follow-up of subtalar arthrodesis patients: what induces adjacent joint arthritis?

Subtalar arthrodesis is considered to be the gold standard operative treatment
for end-stage subtalar arthritis. However, the effect of fusing the subtalar
joint on the surrounding joints remains largely unknown. One long-term outcome
study of 23 patients showed that there was significantly more arthritis seen in
the ipsilateral foot than on the contralateral side, but not in the knee.
1 However this study could have overlooked the presence of arthritic changes in
the joints before the fusion. Sheridan and colleagues looked at pre-operative
radiographs of 70 patients who underwent arthrodesis of the ankle. They found
hind- and midfoot arthritis present in almost all of the patients and conclude
that these changes may not be a consequence of the arthrodesis.
2 For the subtalar joint this has not arrived in literature in detail yet.
A biomechanical study after changes of pressure in the talonavicular,
tibiotalar, and calcaneocuboid joints before and after rigid subtalar joint
immobilization showed data consistent with the theory of adjacent joint
arthritis being the result of an ankle fusion. A substantial pressure increase
in the talonavicular and calcaneocuboid joints at dorsalflexion may be
responsible for the secondary tarsal joint degeneration occurring in late
subtalar arthrodesis.
3 Further investigations might provide evidence supporting either of both
possibilities: adjacent joint arthritis being the result of pre-existing
pantalar arthritis or as a result of the subtalar fusion.

The purpose of this study is to perform a clinical and radiographic follow up
of approximately 100 consecutive patients who received fusion of the subtalar
joint between 1990 and 2010 in the AMC for end-stage ankle arthritis, to
determine the long-term effect of the arthrodesis on the development of
osteoarthritis in the tibiotalar, talonavicular and calcaneocuboid joints. .

A retrospective study is undertaken, for which approval is obtained from the
local Research Ethics Committee of the AMC.
Inclusion criteria: patients with an end-stage osteoarthritis of the subtalar
joint, who have been treated in the AMC by means of arthrodesis of the subtalar
joint between januari 1990 and december 2010.
Primary exclusion criteria: pantalar fusion (combination of subtalar fusion and
ankle fusion in the same setting), ankle fusion prior to subtalar fusion,
re-arthrodesis after failed arthrodesis performed elsewhere, re-arthrodesis
after failed arthrodesis performed in the AMC before 1990. Secondary exclusion
criteria: inability to understand the patient information and the
questionnaires (e.g. mental retardation, severe language barrier), age under
eighteen years, ankle trauma 6 months or less before follow-up.

All arthrodeses of the subtalar joint that have been performed in the AMC
between 1990 and 2010 will be investigated.

The patient has to come to the hospital for about one and a half hour for
anamnese, physical examination, X-rays and questionnaires.
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