Short-term results of total ankle arthroplasty with use of a novel mobile-bearing design.

Total ankle arthroplasty (TAA) is an alternative for arthrodesis in the painful
arthritic ankle. TAA has the advantage of preserving a normal gait pattern with
less compensatory motion in other joints. Ankle arthrodesis, however, is
associated with deterioration of the joints of the foot, which eventually
causes arthritis, pain and dysfunction.
Promising results are seen with 3-component mobile-bearing systems.
Advantages of the mobile-bearing prosthesis is its low intrinsic constraints,
and thereby its low wear characteristics, and the possibility to obtain
adequate stability by implanting a bearing of adequate thickness. Several
different designs of 3- component mobile bearing arthroplasties are in clinical
use, but the literature on most of these new designs is sparse or absent.
Two mobile bearing designs are known for their encouraging intermediate to
long- term follow up: the Buechel-Pappas prosthesis and the STAR prosthesis. A
study by Buechel et al showed a 20-year survival rate of the shallow-sulcus
design (LCS prosthesis) of 74%. After modification to a deeper sulcus-design
(the Buechel-Pappas prosthesis) a 92% survival rate was reported at 12 years
follow-up in a patient population mostly suffering from posttraumatic arthritis
or primary arthritis. Disadvantage of this specific design is that a window has
to be created for the stem of the tibial component, and that the preparation of
the talus is not very well controlled by the instruments.
Fevang et al. found a five to ten year survival for the STAR arthroplasty of
89% and 76% respectively. A five years survival of 70% was found by Anderson.
Disadvantages of the STAR prosthesis are the central groove in the bearing,
making it vulnerable for wear and/or fracture of the polyethylene bearing.
Furthermore, the fixation of the tibial component is not always reliable in
softer bone.
The CCI prosthesis (Van Straten, Nieuwegein, the Netherlands) was developed to
overcome several of the weaknesses of other designs. It requires minimal bone
resection both on the tibial and the talar side, has a good primary stability,
and due to the ceramic coating of the metallic components superior wear
characteristics. This prosthesis was introduced in the Slotervaartziekenhuis in
2003 in order to overcome some difficulties encountered with the use of the
Buechel-Pappas prosthesis.

The objective of this study is to investigate if the CCI prosthesis gives
comparable or better short-term results then other prostheses like the
Buechel-Pappas and Star prosthesis with regard to patient satisfaction,
physical examination and radiology at follow-up.

Observational, cohort study.

Patients need to come for one extra follow-up visit (if not recently been seen
for follow-up), 2 weightbearing X-rays of the ankle need to be made (if not
recently been made), and they have to fill in a questionnaire and 3 VAS scales.