TOTAL ANKLE REPLACEMENT
- Method
- Cementless replacement of the joint surfaces with three components
- Duration
- 60 to 90 minutes
- Recovery time
- 3 to 6 months
In advanced osteoarthritis of the upper ankle the cartilage surfaces between tibia and talus are worn through. The replacement resurfaces exactly those two surfaces – and leaves everything else that carries and guides the foot where it is.
The difference from a fusion comes down to one word: movement. The foot keeps rolling through the step, the gait stays close to your own, and the neighbouring joints do not have to compensate permanently for what is missing above them.
The operation is rarer and technically more demanding than at the hip or knee – around 1,500 ankle replacements are implanted in Germany each year, against hundreds of thousands of hips and knees. The surgeon’s experience shows in the result more clearly here than at the large joints.
How the prosthesis is built
We use the Infinity system with Adaptis technology by Stryker. It consists of three parts that reproduce what the joint used to do on its own: a firm surface above, a rounded dome below, and a gliding surface between them.
- The tibial tray, made of a titanium alloy, covers the lower surface of the tibia.
- The talar dome, made of cobalt-chromium, sits rounded on the talus and takes over its dome.
- The bearing, made of highly cross-linked polyethylene, sits fixed in the tray. It comes in eight sizes with four thicknesses each – so the height of the joint can be set precisely.
Fixation is without bone cement. Tray and talar dome are built up layer by layer from metal powder in a 3D printing process. That creates a porous, sponge-like structure on the underside which is not applied to the part but is part of it. Bone grows into it – the joint holds through a biological bond, not through glue. This cementless fixation was the step that lifted ankle replacement out of its difficult early years.
How the operation proceeds
The approach is at the front of the ankle, in the gap between the tendon of the tibialis anterior and the extensor tendon of the great toe. The nerve and the artery that run there are identified and held aside. The destroyed surfaces on tibia and talus are taken down sparingly – as little bone as possible, because every millimetre counts should the joint ever have to be revised. Guiding instruments make sure the cuts lie on the right axis.
The size of the components is determined with trial implants and checked under fluoroscopy before the final prosthesis goes in.
What is straightened around the prosthesis matters as much. A tilted heel, a shortened calf or an unstable outer ligament would otherwise put the artificial joint under the same one-sided load that used up the original one.
So corrections are part of it: lengthening the Achilles tendon, lifting the hindfoot upright, tightening or reconstructing ligaments. What is needed we plan beforehand from weight-bearing X-rays, with an MRI scan where it helps.
Requirements and limits
What a replacement needs
Several things have to come together for it to bed in safely and carry load:
- Bone that carries load, above all in the talus
- No pronounced osteoporosis around the joint
- Stable ligaments and an axis that can be straightened
- Good circulation and skin that heals reliably
- Any infection must have been healed for at least a year
- Sure balance and the ability to keep to partial weight-bearing
When we advise against it
In these cases fusion is the safe route – not a worse solution, a different one:
- An ongoing infection in the bone or the joint
- Extensive death of the talus
- A malalignment of the axis of more than 20 degrees
- Ligament instability that cannot be corrected
- Charcot foot and other joint destruction caused by nerve damage
- Destructive forms of inflammatory joint disease
- Skeletal growth not yet complete
- Aftercare that cannot realistically be kept to
A failed previous operation on the ankle, by contrast, does not rule a replacement out – the system is expressly approved for that situation. Whether it holds is decided by the bone, not by the history.
Replacement or fusion
This is the real decision, and it is not made on the X-ray but in conversation. Both procedures relieve the pain reliably. They differ in what they ask of you in return.
| Replacement | Fusion | |
|---|---|---|
| Movement | preserved | permanently given up |
| Gait | close to your own | altered; the neighbouring joints compensate |
| Neighbouring joints | spared | loaded more heavily over the years |
| Aftercare | shorter, without a long cast | longer, until the bone has fused through |
| Durability | 89 % at 5 years, 76 % at 10 years | usually lasts for good |
| If it fails | exchange of components, or fusion | a further fusion |
The durability figures are meant honestly: an ankle replacement does not reach the survival of a hip or knee replacement. That is why we tend to advise fusion for young people and for those under heavy physical demands – and a replacement for older patients, for whom movement decides how the day goes.
What the risks are
The approach lies at the front, where the skin is thin and there is little soft tissue beneath it. That explains the commonest problems:
- Wound healing problems – the skin over the ankle is delicate. Rarely, additional plastic surgery is needed.
- A fracture of the inner or outer ankle bone during the operation. It is then fixed with screws and heals along with everything else.
- Loosening of individual components – the commonest reason for a later exchange.
- Pain that persists, or movement that falls short of what was hoped for.
- Infection – rare, but the complication with the greatest consequences.
We say this plainly because the decision for or against a replacement depends on it. Knowing what you are taking on makes for a better decision.
Aftercare following total ankle replacement
The pace is set by the swelling, not by the calendar. The movement present after six months decides the result – which is why it is worked on from the start.
Phase I (0–2 weeks): Wound healing
- An inpatient stay of about five to seven days
- Standing with help the day after surgery, first walking practice from day two
- The foot sits in a removable splint, with partial weight-bearing of about 20 kilograms
- Lymphatic drainage and consistent elevation – the swelling governs everything that follows
- Stitches out around day twelve
Phase II (2–6 weeks): Moving without loading
- Partial weight-bearing on crutches continues; the splint stays
- Lifting and lowering the foot is practised early, partly on a motorised splint
- Physiotherapy as an inpatient or outpatient, depending on progress
- X-ray check at six weeks; the splint can come off afterwards
From week 6: Full weight-bearing, everyday life and sport
- Into a firm ordinary shoe; the crutches are given up
- Rehabilitation takes about twelve weeks in total
- Cycling and swimming after about three months, walking as agreed
- Normal shoes are no problem; high heels are
- X-ray checks at 6 and 12 weeks, at 6 months, and yearly after that
Our ankle specialists
Experienced specialists in replacement of the upper ankle joint
