Minimally Invasive Hallux Rigidus Osteotomy

MIRO stands for Minimally Invasive hallux Rigidus oblique Osteotomy. Mr Redfern created this minimally invasive operation for treatment of hallux rigidus (arthritis of the big toe) . Based on the success of an open operation that has been used for many years, It is a much less invasive method of treating arthritis in the joint at the base of the big toe (arthritis of the hallux metatarsophalangeal joint)

Less pain for patients undergoing Forefoot surgery

Mr Redfern has published many of his techniques in the medical literature and independent studies have confirmed less pain with minimally invasive surgery.

Principles of MIRO Surgery

The aim of this operation is to decompress the arthritic big toe joint.

A number of different open operations have been described to achieve this. Most of these involve removing the spurs on the top of the joint (cheilectomy) combined with creating a few millimetres of shortening in the first metatarsal bone and bringing the metatarsal bone into better alignment. The expectation is that this surgery will improve pain and movement in the arthritic big toe joint.

Mr Redfern has pioneered undertaking this type of surgery using minimally invasive techniques. This involves using tiny drills (burrs) to perform the surgery through small keyhole incisions and using state-of-the-art fluouroscopy (x-ray) guidance.

MIRO General Recovery Information

ANAESTHETIC:

·      Operation performed under general anaesthetic and / or regional anaesthetic

ELEVATION:

• The foot should be strictly elevated for 50 minutes out of every hour of every day for the 2 weeks following surgery

• It does not mean 50 minutes of elevation and then 10 minutes of running around

• It is good to get up regularly but cumulatively, out of each hour, 50 minutes should be spent with the foot elevated above the hip

WALKING:

• You are able to walk on the foot immediately on the day of surgery but only in the surgical shoe provided and only slowly with care to protect the foot

• You must wear the surgical shoe provided at all times when placing the operated foot on the floor, even when going to the toilet at night. Many patients keep the shoe on in bed for the first 2 weeks after surgery 

• You may not walk on the foot at all without the surgical shoe

• The surgical shoe is worn for 6 weeks

• The foot must be kept dry for the first 2 weeks following surgery until reviewed by Mr Redfern

DRIVING:

• You may not drive after the surgery for six weeks unless you have an automatic vehicle and have only undergone surgery to the left foot

SHOWERING:

• You will be provided with a specific bag to cover the operated foot when showering or bathing to keep it dry

SWELLING:

• There will be swelling for 4-6 months after surgery in almost all cases and this can persist in some patients for up to a year

SHOES:

• The patient can usually return to their own shoes after the review by Mr Redfern at 6 weeks after surgery but the choice of shoes will be limited for some months due to swelling in the foot

• Generally, trainers are most comfortable initially

WORK:

• You will need to discuss this with Mr Redfern

• You will need at least 2 weeks off work but possibly much longer 

• If employed in an office role you may be able to return to work from 2 or 3 weeks after surgery although this depends on your occupation and method of commute

• In general, 6 weeks off is required for work involving standing or walking (The hospital will provide a sick certificate for the first 2 weeks; further sick notes can be obtained from your GP)

• If you have the facility to work from home then this will be ideal from week 2 onwards until 6 weeks after surgery when most patients (but not all) can manage to return to their usual work role

PHYSIOTHERAPY:

• Physiotherapy can be a very useful tool in the recovery of patients from this surgery

• Usually arranged to start after the 4-6 week review

• Physiotherapists are able to speed up the recovery process by helping restore a normal walking pattern and mobilization of the foot joints as well as helping to reduce swelling

  
  
  

Summary Of Post-Operative Instructions

MIRO Hallux Rigidus Surgery

Day 1 - 7

· Foot wrapped in bulky bandage and surgical shoe (heel wedge shoe)

· Start walking on the foot in flat surgical shoe only but remain very sedentary

· Elevate 50 minutes of every hour of every day

· Begin moving the big toe with simple exercises

· Simple calf exercises to be performed regularly (anti-DVT)

· DVT stocking on opposite leg (until 2-week review)

· Take pain medication for first 2 days as a precaution (even if no pain present)

· Expect numbness in foot for approximately 10-24 hours

· Blood drainage through bandage can sometimes occur - Do not change bandage

· Do not remove surgical shoe - even at night

Day 7- 14

· Do not remove surgical shoe - even at night

· Remain very sedentary

· Usually little or no pain. Pain medication if required

· Elevate 50 minutes of every hour of every day

· Keep bandaging dry and do not remove (do not change dressing unless instructed)

Weeks 2 - 4

· Follow-up in the outpatients for wound review & removal stitches at 10 – 14 days usually

· Continue walking on the foot onlyin flat surgical shoe until 6 weeks after surgery

· Important to remain very sedentary until 6 weeks after surgery

· Elevation less important after first 2 weeks but still required sufficient to minimise swelling

· Continue moving the big toe with simple exercises

· Shower and bathing allowed (fine to get foot wet)

· May begin to drive automatic vehicle with caution in surgical shoe IF surgery to left foot ONLY(otherwise return to driving at 6-8 weeks post surgery)

4-6 weeks

· Review in the outpatients with x-ray on arrival

· Remove surgical shoe if satisfactory x-ray

· A regular shoe may be worn (should be well cushioned and supportive such as a trainer)

· Physiotherapy recommended to begin at this stage

Beyond 8 weeks after surgery

· Continue physiotherapy

· Can graduallyincrease daily activity from week to week

· No exercising until 8 weeks after surgery when some gentle cycling and swimming allowed

· No running or racket sports (no impact exercise) until 4 months after surgery or as advised

Main Risks Of MIRO Surgery

Mr Redfern undertakes regular detailed audit of his practice. The following is a list of the main risks of surgery and percentages quoted are specific to Mr Redfern’s practice. The main risks include (but not limited to):

Swelling – Initially the foot will be very swollen and needs elevating.  The swelling will disperse over the following weeks and months but will be apparent for up to 6-12 months.

Infection– This is a very small risk with this operation (<1%) You will be given intravenous antibiotics to help prevention.  However, the best way to reduce your chances of acquiring an infection is to keep the foot elevated over the first 14 days as instructed.  If there is an infection, it will likely resolve with a course of antibiotics.

Wound problems– This is a very small risk with this operation (<1%) 

Scar sensitivity– This is a very small risk with this operation (1%) and much more of a concern with traditional open surgery. If the little scars are sensitive following surgery then this usually subsides without treatment. If persistent sensitivity occurs then this can be treated.

Nerve Injury– The risk of the small nerves in the area being directly injured by the surgeon is approximately 1%. However, the nerves can become bruised by the surgery and as a result of the swelling (5%). Whilst this usually recovers, you could end up with some permanent numbness over the big toe area, which might cause irritation but generally doesn’t bother most patients. 

CRPS– This stands for complex regional pain syndrome. It occurs rarely (less than 1%) and is not properly understood. It is thought to be inflammation of the nerves in the foot and it can also follow an injury. It causes swelling, sensitivity of the skin, stiffness and pain. It is treatable but in its more severe form can takes many months to recover.

Delayed and non union– This is when the bones are either slow to heal / join (delayed union) or fail to do so (non union).  If this is painful then further surgery may be needed.  The risk of delayed union is 3% and usually means that the foot remains swollen and irritable for 6-12 months rather than the usual 5-6 months. The risk of the bones not healing at all (non-union) is approximately 1:500 (much less than 1%) but if this occurs then you are likely to require more surgery.

Deep Vein Thrombosis (DVT)– This is a clot in the deep veins of the leg and the risk of this occurring following forefoot surgery is extremely low (much less than 1% and probably in the region of 1:1000) unless you have had one before or have other risk factors. Mr Redfern will discuss this with you but please let him know if you have had a DVT in the past or have been told that you are at higher risk. The fact that you are mobile after surgery and able to take weight through the operated foot helps to minimise this small risk. However, it is sensible to try and move the toes and the ankle regularly following the surgery and also sensible to avoid a long-haul flight in the first 8 weeks following surgery. If a deep vein thrombosis (DVT) occurs then you will require treatment with blood thinning medication to try and prevent any of the clot travelling to the lungs (pulmonary embolus / PE) which can be much more serious.

Stiffness– The risk of increased stiffness in the big toe after this surgery is very low (less than 5%) and can be minimised by beginning to move the big toe immediately after surgery and Mr Redfern will advise you regarding this. Physiotherapy is also likely to be helpful after 2 weeks. Generally patients report an improvement in their big toe range of motion compared to pre-operatively.

Continuing symptoms– Most people (in the region of 90%) are happy or very happy with the results of their bunion surgery but if some of the above problems occur then they may affect the end result. In most cases however, any persisting or new symptoms can be dealt with by additional treatment although this sometimes requires further surgery.

Further Surgery – This is not usual but can be required for a number of reasons (some of which have been mentioned above). The commonest cause of requiring further surgery is to remove a symptomatic screw which is a small additional day-case operation with return to normal footwear expected after 24-48 hours. If the big toe joint remains painful despite this surgery then Mr Redfern may discuss other surgical options such as Cartiva implant surgery and fusion surgery of the joint.

These notes are intended as a guide and some of the details may vary according to your individual surgery or because of special instructions from Mr Redfern