How a nail through the shin bone can fix a worn-out knee
THOUSANDS of younger people with osteoarthritis could be spared the ordeal of having a knee replacement – by having a nail driven into their shin. The surgery, called intramedullary high tibial osteotomy (IMHTO), sees the surgeon remove a wedge of bone in the tibia in order to straighten out the bone. This alleviates pressure on the knee joint.
A magnetic nail is then driven straight through the shin bone and held in place with screws below the cut in the bone.
The length of the nail can be adjusted by an external remote controller, so the size of the gap and alignment of the bone can be fine-tuned post-surgery.
A similar operation is currently used to treat the problem, involving plates and screws, but as these are fixed during the operation, any adjustments require additional surgery.
The UK patients having magnetic nail surgery are part of an international trial looking to establish whether this could become the new gold standard treatment.
The new magnetic nail operation being carried out by surgeons at Southampton General Hospital does not completely eliminate the need for replacement, but it can save younger people with worn-out knees from having to undergo full knee-replacement surgery until they are much older.
Amir Ali Qureshi, a consultant knee and limb reconstruction surgeon at University Hospital Southampton NHS Foundation Trust who is using the magnetic nail, said: ‘The population of younger people with worn or damaged knees is growing.
‘They may well have damaged their knee taking part in sport, so we want to keep them active but avoid a knee replacement until they get to about 60.’
Mr Qureshi, who has performed IMHTO surgery on three patients as part of the trial, said: ‘This is potentially a fantastic development in our options for patients with early-stage arthritis of the knee as it enables us to control the amount of opening throughout the course of treatment and to fine-tune as needed. While standard high tibial osteotomy using a plate enables us to avoid replacement surgery and prolong the life of the joint, the fact that it is fixed means that any issues with the angle of the bone require further operations.
‘If the knee is not corrected fully it can lead to symptoms persisting, while over-correction can cause premature wearing of the undamaged side of the knee.’
At least eight million Britons suffer from the degenerative joint disease where the protective cartilage wears out, causing pain, swell- ing and stiff joints. It is commonly caused by wear and tear over time, and affects the most frequently used joints – in the knees, hips and hands.
In knee osteoarthritis, the lack of cushioning cartilage leaves bone to grind on bone, causing it to thicken and grow, forming bony spurs.
This puts pressure on the joint and also causes the tibia bone – the large bone in the shin – to become bent.
About 90,000 Britons every year need to have an artificial knee fitted to address the problem. However, these can wear out and need to be replaced.
Multiple operations can worsen the situation for the patient as well as adding to the NHS’s annual £585 million knee-replacement surgery bill.
Sarah Preece, a 32 year-old former netball player, became the first patient to undergo magnetic nail surgery a year ago.
The mother-of-two from Salisbury, Wiltshire, suffered a ruptured cruciate ligament in the knee at the age of 18, and after many operations on damaged cartilage in the knee she was forced to quit playing four years ago.
She said: ‘I had crippling pain walking, and even when I was not putting weight on it when I was sitting down or in bed at night.
‘My kids are small and quite demanding and my husband was having to take charge quite a lot of the time. If they ran off while we were out walking, I couldn’t chase after them.’
She added: ‘The operation has transformed my life. I am no longer in pain and I am able to go out on long country walks with the family once again.’