You may not know it, but your best friend could be wearing them. Not that they are anything to be embarrassed about, but discussing the orthopaedic devices you put in your shoes is just not the type of conversation you have over a cup of coffee.
Experts estimate that up to 50 per cent of us could benefit from orthotics. They can help an astonishing range of problems, whether intrinsic to the foot or not.
"One very common problem is a heel spur, which results in pain under the arch and heel of the foot. This is caused by an overpull of the planter fascia ligament. Another common reason why people wear orthotics is to get rid of knee pain, hip pain or back pain caused by malalignment of the foot or lower limb joints," says Joanne McKenna, a podiatrist and member of the Society of Chiropodists and Podiatrists. "People with abnormal walking patterns caused by flat feet, high arched feet or knees that rotate inwardly will also benefit from orthotics," she adds.
McKenna describes the feet as the foundations of the body; orthotics are used to steer it. This is particularly relevant, given that few of us are symmetrical. Most of us have one foot slightly larger than the other, or one leg slightly longer than the other. If the discrepancy is significant, it can cause people to walk lopsidedly, perhaps in pain.
Before orthotics can be fitted, however, a patient must undergo a biomechanical assessment. "This involves taking measurements in standing [or weight-bearing] and lying [or non-weight-bearing] positions," says Siobhβn Campbell, a chartered physiotherapist. "Orthotics are usually prescribed for chronic or recurring problems. However, prescribing orthotics is only 50 per cent of the treatment. Exercises are very important, as is wearing the correct shoes to support the orthotic."
Sportspeople are prime candidates for orthotics. Through overuse of muscles, tendons and joints, otherwise slight discrepancies can cause problems. "You need to have your feet hitting the ground in a biomechanically advantageous way. If you have a pronated foot" - or fallen arches - "there is extra pressure on the ankle joint and on the bones below the knees, so you can end up with problems such as shin splints. Shin splints are the bugbears of all athletes," says Conor O'Brien, who was doctor to the Irish Olympic team at the Atlanta Olympics, in 1996.
Keith Wood, Sonia O'Sullivan, Catherina McKiernan and Mark Carroll are among the Irish sportspeople who have worn orthotics. Carroll is keen to stress that correct diagnosis and strengthening exercises to accompany the orthotics are crucial.
"I had hypermobility of my ankle joint, which meant that the ankle swivelled a lot and the tendons were weak. It wasn't until I got my fifth pair of orthotics that I was given good strengthening exercises to do as well. Before that, I was constantly injured. But since then, I have had no problem whatsoever," explains Carroll from his base in Rhode Island, in the United States.
"You can spend a lot of money on orthotics and they might not do the trick. If the orthotics are poorly made, not supported enough or made from poor materials, they can redistribute the pressure to a different part of the foot. Then, you can risk a fracture in another place. I have seen sportspeople in the United States and in Ireland who get orthotics and have no follow-up exercise programme or monitoring. Orthotics in themselves are not a miracle cure."
There are two principal approaches to orthotic fittings. The more traditional uses a measuring tape and a plaster cast; the newer uses electronic equipment. There is much debate about the merits of each approach.
Joanne McKenna, whose company, Podiatrists Ltd, also manufactures orthotics, believes computers can't diagnose conditions. "In order for someone to be prescribed a device, the podiatrist, chiropodist or chartered physiotherapist has to identify the cause of the problem. All you need to prescribe good orthotics is good training and qualifications, your hands, eyes, measuring tape and maybe a goniometer which measures joint orientation. You don't need a pretty picture of where the highest pressure on your foot is," she says.
McKenna also cautions against the fitting of orthotics by unregistered practitioners. "I once had a patient with brittle-bone disease who was fitted with a metal arch support in a shop. She sustained 15 fractures as a result. If the fitter had been qualified, he or she would have known that a rigid device is contraindicated with such a condition."
Kieran Carew of Foot Health Ltd believes electronic equipment cuts out human error, as the computer readings are sent electronically to the manufacturing plant. Foot Health has recently introduced the equipment - at £6,000 per system - to the market in the Republic, as well as supplying it to hospitals, orthopaedic consultants, physiotherapists and podiatrists.
O'Brien sees the new equipment as an advance. "Before, you needed a highly trained physiotherapist or podiatrist to do a biomechanical assessment. Now, the skill is in-built into the technology. You can get up to speed and start fashioning orthotics properly, under the supervision of a doctor."
The Society of Chiropodists and Podiatrists of Ireland is at 01-2024939. The Irish Society of Chartered Physiotherapists is at 01-4022148 (www.iscp.ie)