Monday, July 4, 2011

Correction of Moderate to Severe Coronal Plane Deformity with the STAR Ankle Prosthesis

Authors:  Rogor A. Mann, MD; Jeffrey A. Mann; Sudheer C. Reddy

Prior studies have demonstrated a correlation between the degree of
preoperative coronal plane deformity and failure following ankle
replacement. We reviewed all of our patients who underwent ankle
replacement utilizing the STAR prosthesis from 2000 to 2009 to evaluate
the outcome of those with moderate (10 to 19 degrees) and severe (20
degrees or greater) coronal plane deformity. Materials and Methods: Out
of 130 consecutive patients, 43 patients had at least 10 degrees of
preoperative coronal plane deformity. Twenty-five ankles had 10 to 19
degrees degrees of deformity and 18 ankles had 20 degrees
or greater deformity. Average age was 66 years. Average length of
followup was 41 (range, 12 to 98) months. Results: Average talar
preoperative deformity was 17.9 (range, 10 to 29) degrees, while
average initial talar postoperative deformity was 3.5 (range, 0 to 12)
degrees. Average final talar postoperative deformity was 4.7 (range, 0
to 14) degrees. Preoperative and final correction of deformity was
statistically significant (p <0.01), but there was no significant
difference between initial and final postoperative correction. Overall,
recurrence of the preoperative coronal plane deformity occurred in six
of 43 patients (14%). All three patients who had deformities over 25
degrees developed recurrences. Correction of the coronal plane
deformities was achieved by using intraoperative soft-tissue balancing,
including deltoid ligament release in 12 patients
and lateral ligament reconstruction in one patient. Deltoid ligament
release was found to be necessary for all patients with greater than 18
degrees of varus plane deformity. Conclusion: Correction of moderate to
severe coronal plane deformity with the STAR prosthesis was achievable
with only soft-tissue balancing procedures with predictable results
especially for deformities less than 25 degrees.

Level of Evidence: IV, Retrospective Case Series

Key Words: STAR; STAR Ankle; Scandinavian Total Ankle Replacement;
Ankle Replacement; Coronal Plane Deformity; Valgus; Varus; Deltoid

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