Total ankle replacement compatible with ligament function produces mobility, good clinical scores, and low complication rates: an early clinical assessment.
BACKGROUND
A three-part ankle replacement was developed to achieve compatibility with the natural ligaments by allowing fibers on the medial and lateral sides to remain isometric during passive motion. Unlike all current prostheses, the new design uses nonanatomically shaped components on the tibia and talus and a fully conforming interposed meniscal bearing.


OBJECTIVE
Does this new design restore ankle mobility, improve clinical score, and result in low complication and early revision rates?


METHODS
We reviewed 51 patients in whom 51 prostheses were implanted in a seven-center trial from July 2003 to July 2006. The mean age of the patients at surgery was 61.5 years (range, 35.1-82.5 years). We used the AOFAS score to assess clinical outcome. We used lateral radiographs to assess function. The minimum followup was 24 months (mean, 30 months; range, 24-48 months).


RESULTS
The mean preoperative AOFAS score of 38.5 increased to 76.9, 79.1, 76.4, and 79.0 at 12, 24, 36, and 48 months, respectively. We observed a correlation between meniscal bearing movement on the tibial component (mean, 3.4 mm; range, 2-12 mm) and range of flexion at the replaced ankle (mean, 27.4º; range, 16º-53º). We revised one arthroplasty in the second postoperative year for lateral impingement, providing a 3-year cumulative survival rate of 97% and performed one other secondary operation for hindfoot pain.


CONCLUSIONS
These data suggest the new prosthesis can provide short-term restoration of ankle mobility, a good clinical score, and low complication and failure rates. Longer followup with larger numbers is required.


METHODS
Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
Giannini
Sandro
S
Department of Orthopaedic Surgery, Istituto Ortopedico Rizzoli, Bologna, Italy.
Romagnoli
Matteo
M
O'Connor
John J
JJ
Malerba
Francesco
F
Leardini
Alberto
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000843:Ankle Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D019643:Arthroplasty, Replacement / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D007558:Italy; D007595:Joint Prosthesis; D017844:Lateral Ligament, Ankle / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011474:Prosthesis Design; D011859:Radiography; D016059:Range of Motion, Articular; D020127:Recovery of Function; D012086:Reoperation; D013997:Time Factors; D016896:Treatment Outcome; D016474:Weight-Bearing