Total Ankle Replacement with Use of a New Three-Component Implant

Authors: Pascal F. Rippstein, MD; Martin Huber, MD; J. Chris Coetzee, MD; Florian D. Naal, MD

Journal:  JBJS TAR 3 Component System

Abstract: 

Background: Total ankle arthroplasty has evolved over the past decade, and newer three-component implants have demonstrated favorable clinical results and improved survivorship. The present study analyzed the clinical and radiographic results of the first 240 total ankle arthroplasties performed by the authors with one of these new three-component prostheses. Methods: Two hundred and forty consecutive primary total ankle arthroplasties were performed in 233 patients (115 women and 118 men; mean age, 61.6 years) between November 2003 and October 2007 with the Mobility prosthesis. Intraoperative and postoperative complications, reoperations, and failures were recorded. The American Orthopaedic Foot & Ankle Society hindfoot score and a visual analog scale score assessment of pain were determined at each follow-up visit. Range of ankle motion was measured on functional radiographs, and the radiographs were studied to assess component positioning, radiolucencies, new bone formation, and periprosthetic bone cysts.  Results: Two hundred and thirty-three of the arthroplasties were available for follow-up at least one year after surgery. The mean duration of follow-up was 32.8 ± 15.3 months. There were ten intraoperative complications (4.2%) and twenty postoperative complications (8.6%). A reoperation was necessary in eighteen ankles (7.7%). Five arthroplasties (2.1%) failed at a mean of twenty-seven months after surgery. The mean American Orthopaedic Foot & Ankle Society hindfoot score improved from 48.2 to 84.1 points (p < 0.001). The mean pain level decreased from 7.7 to 1.7 points (p < 0.001). The mean total range of ankle motion improved from 19.8° to 21.9° (p < 0.001). The tibial component had a mean of 2.1° of varus and a mean posterior slope of 6.0° relative to the tibial axis. The prevalence of nonprogressive radiolucency ranged from 1.8% to 37.3% in the ten zones surrounding the tibial component, and from 0 to 2.2% in the three zones surrounding the talar component. Conclusions: The short-term clinical and radiographic results after Mobility total ankle arthroplasty are encouraging and are at least comparable with those associated with other modern three-component implants. The minimum duration of follow-up of one year is short, and studies with longer follow-up are needed to confirm our findings.

Keywords: 
ankle, ankle replacement arthroplasty, osteoarthritis of ankle, tibia, prosthesis implantation

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

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

Foot & Ankle International: July 2011 (Vol.32 #7)

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

Release

Total Ankle Replacement in the Varus Ankle

Authors:  Shock, R., Christensen, J., Schuberth, J. (2011). 

Reviewed by:  James Johnston, DPM

The Journal of Foot and Ankle Surgery. Scientific Literature Review: 50, 5-10. June 2011

This is a retrospective study of patients with more than 5º of ankle varus arthrosis who underwent total ankle replacement before October 2007.  Patient preoperative, immediate postoperative and most recent post operative weight bearing films were evaluated.  The degree of varus deformity was determined by measurement of the long axis of the tibia to a perpendicular axis of the talar dome on AP and mortise views.

Results:
A total of 26 patients with preoperative varus ankle deformity of greater than 5 degrees were reviewed in the study.  Patient ages ranged from 63.85 ± 9.33 years, with 7 females and 19 males.  The average follow up was 16.69 ± 7.26 months.  The average varus deformity was 18.3º ± 6.4º on the AP preoperative radiograph and 16.8º ±6.79º on the mortise projection.  The immediate postoperative radiographs were measured and showed correction of 19º on the AP and 17º on mortise projections.  All corrections where within 1º of postoperative films at follow up. There was a significant change in coronal plane correction of varus deformity on both AP and mortise views indicating either one can be used for preoperative planning.  The sequence of corrective maneuvers for varus deformity was:  Ancillary pedal procedures including but not limited to subtalar arthrodesis, ankle ligament reconstruction and talonavicular arthrodesis.  A standard incisional approach was used followed by a medial deltoid sleeve release, lateral gutter resection, talar deformity reduction, tibial-talar preparation, component insertion and lateral ligament placation.

Conclusions:
At the time of review there has been no standard surgical approach to the varus ankle TAA in foot and ankle literature.  This article demonstrates a stepwise approach to management of the rearfoot deformity and presents a convincing although limited case review for the indication of TAR in the varus ankle.  The article points out that the varus ankle deformity frequently involves ligamentous imbalance with leads to a maladaptive joint.  Previous literature has provided us with the suggestion that moderate to severe (10 º to 20 º) coronal plane deformity of the tibiotalar complex may be a contraindication to TAA.  This article argues that with proper soft tissue balancing and the reestablishment of the plantigrade foot with a neutral ankle mortise, success can be found at least in the intermediate follow up.