Ankle Arthroplasty - CC Tai 26/6/2001

Started in 1970s (Morton Murdock) after success with THR / TKR. In the 1970s, good results and implant survival were 80-85% of cemented implant esp RA or patients with low physical and restricted activity. Unfortunately, as time went on, many of the early success become failures. Published studies in the 1980s with longer follow up showed that cemented implant did not provide lasting relief and failure occurred in high percentage : loosening 20- 60% (5-10 yrs f/u), revision 10 - 40% (5-10 yrs f/u). Recent studies with second generation prosthesis have produced more encouraging results: 85-90% good to excellent results, failure rate 5-6% (up to 10 yrs f/u)

Indication

- rheumatoid arthritis involving multiple joints

- posttraumatic or primary OA in older inactive patients (?good lig stability, reasonable normal anatomy, lack of significant varus or valgus deformity < 20 deg)

- ? ankles with marked deformation and destruction, esp subtalar or midtarsal joints are involved

Contraindication

- talus AVN or on steroid, charcot joint, neurological problems, absence of muscular function

- previous ankle arthrodesis with removal of the malleoli, severe tibiotalar malposition, acute or chronic infection

- (Relative contraindication - youthful, active individual with degenerative ankle joint, previous infection, vasculitic ulcers, fused ankle)

Design/Biochemical Rationale

- 2 or 3 components

- various type of fixation : pegs, long/short stems, cylindrical/rectangular bars

- tibial components made of polyethylene (old) or metal-backed (new)

- constrained (TPR,  ICLH, Conaxial, Oregon and Mayo), unconstrained (St George-Buchholz, Smith, Newton, Irvine), semiconstrained - second generation (LCS, STAR, Agility)

Important consideration : anatomy of the ankle joint with variability in axis of rotation and subsequent motions, forces generated across joint, stability of joint, amount of bone resection required for implantation (minimal to allow better bone support, for fusion/ reimplantation and to prevent talus AVN), Cement or no cement

Approach

- anterior - common, curving the incison to stay medial to the AT and EHL. Beware of the cutaneous branch of the sup peroneal nerve

- posterior - excision of an os calcis bone block inc TA insertion

- Lateral - osteotomy of the fibula and division of the lateral lig.

Complication

- Loosening

- delayed wound healing & skin infection

- nerve injuries

Please log in to view the content of this page.
If you are having problems logging in, please refer to the login help page.