Silastic Big Toe (1st MTPJ) Replacement

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Expert Patient Guide  ·  Foot & Ankle Surgeon  ·  London & North London

Silastic First MTP Joint Replacement (Silicone Big Toe Joint Replacement)

A patient guide to big toe joint replacement for hallux rigidus — by Mr Matthew Welck, Consultant Orthopaedic Foot & Ankle Surgeon, Royal National Orthopaedic Hospital (RNOH), Stanmore, London and North London.


If you have severe arthritis of your big toe joint (known medically as hallux rigidus), a silastic joint replacement is one of the surgical options that can relieve pain while keeping some movement in the toe. This guide explains why the operation is done, how to prepare, what happens on the day, and what recovery involves.

Mr Matthew Welck is a Consultant Orthopaedic Foot & Ankle Surgeon, and one of London and North London’s leading foot and ankle specialists. Mr Welck treats the full range of foot and ankle conditions — from sports injuries to complex arthritis and total ankle replacement — across central London, North London and Hertfordshire.

At a glance

AT A GLANCE

Silastic First MTP Joint Replacement
ProcedureSilastic (silicone) first MTP joint replacement of the big toe
TreatsEnd-stage hallux rigidus (severe big toe arthritis)
AnaestheticGeneral or spinal — performed as a day case
Hospital stayHome the same day
Weight-bearingWalk immediately in a special stiff-soled shoe
Back in normal shoesAround 6 weeks
Evidence97.2% of implants still working at around 5 years; around 9 in 10 patients satisfied (in correctly selected patients)

Section 1

1. Why have the surgery? (The benefits)

Hallux rigidus is a wearing-out (arthritis) of the joint at the base of the big toe. It causes pain, stiffness, and often a bony lump on top of the joint that rubs against shoes. In the early stages we treat it without surgery — using stiff-soled or roomy footwear, insoles, painkilling gels and tablets, and occasionally a steroid injection. Surgery is only considered when these measures no longer control the pain and the arthritis is severe (“end-stage”).

For end-stage arthritis there are two main operations: fusion (arthrodesis), which permanently stiffens the joint, and joint replacement. A silastic replacement removes the worn joint surfaces and inserts a small, flexible silicone spacer that works like a hinge. Its key advantage over fusion is that it preserves movement in the toe rather than stiffening it completely, while still relieving pain.

What the evidence shows

The results are reassuring. In a large study of 108 of these implants published in the Bone & Joint Journal (Clough & Ring, 2020), average pain scores fell from 7 out of 10 before surgery to about 1 out of 10 afterwards, and validated foot questionnaire scores improved dramatically. Around 9 in 10 patients (91%) said they were satisfied with their operated toe.

In short, the benefits are:

  • Reliable, long-lasting pain relief
  • Preserved movement in the toe (unlike a fusion)
  • A quick day-case operation with immediate walking
  • Keeps future options open — if needed later, it can usually be revised to another implant or a fusion

This procedure is most suitable for an older, non-sporty patient looking to preserve range of movement. Sporty patients will wear the implant out quickly, and it is not advised for high-impact activity due to a higher risk of implant failure, complications and the need for revision when the implant is subjected to high stresses.

Section 2

2. Preparing for the surgery

Before your operation you will attend a pre-assessment appointment, where the team checks you are fit for anaesthetic and advises whether to pause any medications (for example blood thinners). You will not be able to drive straight after surgery, so arrange a lift home and some help for the first couple of weeks. Plan time off work — desk-based roles typically need 2–3 weeks, and more if you are on your feet.

Helpful items to buy in advance

  • A foam leg elevator (wedge). Keeping your foot raised comfortably above the level of your heart is the single most effective thing you can do to reduce swelling and pain in the first two weeks. A firm foam wedge is far better than a stack of pillows.
  • A waterproof cast/dressing protector. A product such as the “Limbo” seals over your dressing so you can shower without getting it wet, which helps keep the wound clean and dry.

Further reading before your operation:

Section 3

3. What does the surgery involve?

The operation is usually carried out under a general anaesthetic (you are asleep) or a spinal anaesthetic (numb from the waist down), often with a local anaesthetic block to keep the foot comfortable afterwards. It takes around 30–45 minutes.

A small cut is made on the top of the big toe joint. The surgeon removes the worn, arthritic joint surfaces and any bony lumps, then gently shapes the ends of the two bones. A small, flexible silicone implant with two stems is slotted into the bones, one stem into each side. It sits like a cushioned hinge, taking the place of the old joint so the toe can bend without the bones grinding painfully together. The skin is closed with stitches, a supportive dressing is applied, and you are placed in a special stiff-soled shoe.

Section 4

4. How long will you be in hospital?

This is a day-case procedure, which means you go home the same day — usually a few hours after surgery, once you are comfortable, have eaten and drunk, and the team is happy you can move around safely on your special shoe. You can put weight through the heel and outside of the foot straight away, so you will not need to be admitted overnight in most cases.

Section 5

5. What does recovery look like?

Recovery is staged. Following the plan closely — especially the elevation in the first two weeks — makes a real difference to swelling, comfort and the final result.

Early (first 2 weeks)

Rest at home with your leg strictly elevated — foot above heart level as much as possible, coming down only for short trips to the bathroom and for food. This is the most important phase for controlling swelling. Keep the dressing clean and dry (use your waterproof protector to shower). You will be reviewed at around two weeks for a wound check and removal of stitches.

Mid-term (weeks 2–6)

From about two weeks, once the wound has healed, you move into a flat post-operative shoe with a light bandage for a further two weeks, gradually increasing how much you are on your feet. At around four weeks you can usually progress into rigid-soled trainers for the next couple of weeks, which support the toe while it settles.

Long-term (6 weeks and beyond)

By around six weeks most people are back in comfortable, supportive normal shoes and returning to everyday activities. Any residual swelling continues to settle over the following few months — this is normal and can take up to six months to fully resolve. Most patients return to low-impact exercise and sport by around three months, building up gradually. Your surgeon will guide your individual return to higher-impact activity.

Section 6

6. What are the risks?

Overall, this operation has low complication rates, and most problems that do occur are minor and settle with simple treatment. In the study of 108 cases, most complications did not affect the final outcome. The main risks specific to this procedure are:

Main procedure-specific risks

  • Implant wear or fracture over the long term. The silicone implant is very durable, but can occasionally break after many years of use. In the study, only two implants fractured — at around 10 and 13 years — and both were successfully replaced.
  • Ongoing pain or stiffness. A small number of patients have some residual pain or a stiff toe. This is usually mild and rarely needs further surgery.
  • Cysts on X-ray. About 1 in 5 patients develop small fluid pockets (cysts) in the bone that show up on X-ray. Reassuringly, in this study these were non-progressive, caused no symptoms, and did not affect the result.
  • Infection. Superficial infection is uncommon and usually clears with antibiotics; deep infection is rare and occasionally needs further surgery.
  • Transfer pain (metatarsalgia). A few patients notice aching under the neighbouring toes, which is usually managed with an insole.

Importantly, the study found 97.2% of implants were still working at around 5 years, with no sign of the progressive bone loss reported with older single-stemmed designs.

These risks are explained in more detail in our dedicated risk leaflet:

Please read this in conjunction with this leaflet before signing your consent form. Mr Welck will discuss the risks that are most relevant to your individual case in clinic.

Section 7

7. Frequently asked questions

How is this different from a big toe fusion?

A fusion permanently stiffens the joint so it can no longer bend, whereas a silastic replacement keeps some movement. Both relieve pain reliably; the replacement is often preferred by patients who want to retain toe flexibility.

How long does the implant last?

The evidence is encouraging: 97.2% of implants were still functioning at a mean of around 5 years, and other studies report good results out to 13–19 years. If an implant does eventually wear out, it can usually be replaced.

Will I be able to walk straight after the operation?

Yes. You can bear weight immediately in a special stiff-soled shoe, though you should keep the foot elevated as much as possible for the first two weeks to control swelling.

When can I drive again?

Not until you are out of the post-operative shoe, can safely control the pedals and perform an emergency stop — usually around 6 weeks. Always check that you are safe and that your insurer is satisfied before driving.

When can I go back to sport?

Most patients return to low-impact activity by around 3 months and build up gradually. Impact sport such as running and jumping is not advised.

Is the surgery available privately in London?

Yes. Mr Matthew Welck offers assessment and treatment of hallux rigidus, including silastic big toe joint replacement, at his London, North London and Hertfordshire practices. To arrange a consultation, contact the team at secretary@matthewwelck.com or 07547 395 270.

About Mr Welck

About Mr Matthew Welck

Mr Matthew Welck is a Consultant Orthopaedic Foot & Ankle Surgeon at the Royal National Orthopaedic Hospital (RNOH), Stanmore, and Honorary Associate Clinical Professor at UCL. He is widely regarded as one of the best foot and ankle surgeons in London and North London, with specialist expertise in big toe arthritis, sports injuries, complex reconstruction and total ankle replacement. He has over 50 peer-reviewed publications and is an active educator and researcher in weight-bearing CT imaging and 3D-printed surgical planning.

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This information is intended as a general guide and does not replace individual medical advice. Please discuss your specific circumstances with your surgeon.



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