Ankle joint replacement is a newer operation than the well-established replacement operations for hip and knee joints.

Whereas the hip is a ball in socket joint and the knee is fundamentally a hinge joint, the ability of the ankle and forefoot to flex, extend, invert and evert makes is a complex joint. These actions are necessary to be able to walk over uneven ground.

Indications and other options

Indications¹

Pain due to severe ankle arthritis, where conservative treatment is not providing adequate pain relief. (Ankle joint replacement does not generally increase mobility of the joint, although it usually maintains existing range of movement.)

The arthritis may be due to:

• Osteoarthritis, including post-traumatic and after sports injuries.
• Rheumatoid arthritis.

Other treatments for ankle arthritis¹

Conservative treatments may be tried first:

• Non-surgical, including:
  • Analgesia,
  • Orthotics, such as a splint and/or a shoe with a 'rocker sole'.
• Surgical:
  • Arthroscopic debridement.
  • Ilizarov joint distraction - an external frame fixed around the joint.

• It has a much lower rate of failure or complications and does not 'wear out'. It is equally effective for pain relief.
• The ankle joint will be rigid, although there can be some compensation from increased mobility at nearby joints.
• There is concern that it may lead to increased strain and therefore arthritis of nearby joints, particularly the subtalar joint. In practice, there seem to be radiological changes of the subtalar joint but few symptoms.

Replacement or fusion?¹

Factors to consider:

• Function of the whole limb and mobility of surrounding joints.
• Suitable patients for joint replacement tend to be in the older age group (over 50) and prepared to accept a rather higher risk of failure than with hip or knee arthroplasty.
• Younger patients are approached with more caution, as they have longer expected life, tend to be more active and so put prosthetic joints under more stress.
• Occupation and its likely stress on the joint must be considered.
• With bilateral ankle arthritis - a bilateral fusion can be disabling for certain tasks, e.g. getting up from a chair; in this situation, it may be preferable to replace one or both joints.

Contra-indications¹

• Muscle or neurological dysfunction of the limb.
• Heavy manual occupation.
• Severe deformity of the joint.
• Local soft-tissue problems, e.g. skin ulcers.
• Previous infection of the joint.

Types of prosthesis

Examples are:

• Agility® Total Ankle System.³
• Scandinavian Total Ankle Replacement (STAR).⁴
• Buechel-Pappas® (BP) Ultra Total Ankle Replacement.⁵

Preoperative and postoperative practical considerations

• Deep vein thrombosis (DVT) prophylaxis may be needed (as with any leg operation).
• Practical points after ankle replacement surgery¹ (details will vary according to surgical practice and a patient's needs):
  • A splint or plaster cast will be fitted, and the patient may be non-weight bearing for several weeks.
  • Physiotherapy may be advised.
  • Driving may be possible after three months.

Outcomes

Function after ankle replacement¹

• Gait can be normal or near-normal (assuming the rest of the limb is unimpaired).
• Running is unlikely.
• Cycling and swimming are possible.

Complications

The following complications have been reported. (The figures quoted are examples only, taken from a systematic review⁶ and a private clinic website¹ with figures rounded to the nearest %):

• Deep infection of the joint (1-2%).
• Wound infection (1%).
• Delayed wound healing or breakdown (5%).
• DVT or pulmonary embolism (1%).
• Pain and stiffness despite replacement (3-5%).
• Malleolar fracture (10%).
• Impingement (14%).
• Failure of implant (85% survival at 10 years).
• Further surgery needed (13%).
• Fusion needed following replacement surgery (6%).

Document references

1. The Foot and Ankle Clinic, Information on foot and ankle problems and their surgical treatment from a private orthopaedic clinic. Written by orthopaedic surgeon Mark Herron. Updated 2004-8
2. Trichard T, Remy F, Girard J, et al; Long-term behavior of ankle fusion: assessment of the same series at 7 and 23 year (19-36 years) follow-up. Rev Chir Orthop Reparatrice Appar Mot. 2006 Nov;92(7):701-7. [abstract]
3. Knecht SI, Estin M, Callaghan JJ, et al; The Agility total ankle arthroplasty. Seven to sixteen-year follow-up. J Bone Joint Surg Am. 2004 Jun;86-A(6):1161-71. [abstract]
4. Anderson T, Montgomery F, Carlsson A; Uncemented STAR total ankle prostheses. Three to eight-year follow-up of fifty-one consecutive ankles. J Bone Joint Surg Am. 2003 Jul;85-A(7):1321-9. [abstract]
5. San Giovanni TP, Keblish DJ, Thomas WH, et al; Eight-year results of a minimally constrained total ankle arthroplasty. Foot Ankle Int. 2006 Jun;27(6):418-26. [abstract]
6. Stengel D, Bauwens K, Ekkernkamp A, et al; Efficacy of total ankle replacement with meniscal-bearing devices: a systematic review and meta-analysis.; Arch Orthop Trauma Surg. 2005 Mar;125(2):109-19. Epub 2005 Feb 3. [abstract]

Internet and further reading

• Doets HC, Brand R, Nelissen RG; Total ankle arthroplasty in inflammatory joint disease with use of two mobile-bearing designs. J Bone Joint Surg Am. 2006 Jun;88(6):1272-84. [abstract]

Acknowledgements