What is Total Ankle Replacement?
Ankle Replacements are effective at pain relief, and preserve the range of motion of the ankle joint. As a result, it reduces the subsequent stresses upon the adjacent joints in the foot and the knee and decreases the risk of developing arthritis in those joints compared to fusion.
Ankle replacement results in a more natural gait pattern and walking pattern on inclines and stairs and as a result research has shown high satisfaction rates in outcome scores. Ankle replacement can mean the adjacent joints such as the subtalar and talonavicular joint have less stress placed upon them compared to an ankle fusion.
In patients with deformity and arthritis in multiple joints as well as the ankle, Ankle replacement combines well with fusions of the adjacent joints to provide pain relief and function with a corrected foot and ankle shape.
It is well studied in the Australian Joint Registry which monitors all Total Ankle replacements put in in Australia. This has demonstrated advances in survivorship with the use of Fixed bearing Prostheses, with significant improvements since their introduction in 2015. These have a 7 year revision rate of 4.3%. The InBone and Infinity components are fixed bearing.
The Infinity and InBone replacements in patients over 65 have approximately a 7% risk of failure after 10 years, and patients aged 55-65 approximately 10% risk of failure after 10 years.
Ankle replacement is suited to patients ideally over 60 with range of motion of the ankle and particularly for patients with arthritis in the surrounding joints.
Surgery
Before surgery a CT scan is performed to prepare the customised Patient Specific Jigs. An engineered plan is then used to create the ideal mechanical alignment, and specific anatomical details are incorporated. The jigs are made and sent to the hospital. This process takes 6 weeks.
At Surgery an incision is made on the front of the ankle, and the specialised jigs are fitted to allow the bone cuts to be made. The Prosthetic trials are fitted, and then balancing of the joint and ligaments is performed. This is important for a stable joint with good range. Occasionally to balance a joint properly other procedures around the foot and heel are required. X-rays are taken during the case to confirm alignement.
The Definitive Implants are then inserted. The ankle is placed in a plaster back-slab following surgery.
The post operative course is 2 weeks elevation, then 4 weeks of walking in a boot and range of motion exercises, before commencing a graded return to activities. Full recovery can take up to 6 months.
Total Ankle Replacement
Can be a treatment option for the following conditions