Bionic knees made to fit perfectly   by Eveline Gan     "Are you in a wheelchair?" Those were the first words K S Chin's friends said to him on the phone after his knee replacement surgery last month.   Mr Chin's friends can be forgiven for being less than optimistic. After all, the 57-year-old manager, who suffered from osteoarthritis, had gone for a relatively complicated surgical procedure to fix not one, but two creaky knees.   Little did they know that Mr Chin had already taken baby steps using a walking frame just a day after his operation.   Mr Chin is the first person in Singapore and around the region to have undergone a bilateral knee replacement using a new procedure that uses a customised jig, according to Dr Kevin Lee, medical director of Singapore Medical Group's (SMG) Centre for Joint & Cartilage Surgery and Singapore Sports Orthopaedic Surgery Centre.   Dr Lee performed the surgery, dubbed patient-specific instrumentation (PSI) in medical lingo, at Mount Elizabeth Hospital.   Besides SMG, several restructured hospitals including Tan Tock Seng Hospital (TTSH) and the National University Hospital also offer the procedure. So far, TTSH has performed five such surgeries.       CUSTOM MADE TO FIT PERFECTLY   Knee replacement surgery involves removing damaged knee joint areas, and replacing them with metal and plastic implants. A jig is a cutting guide used to make cuts to the patient's femur (end of the thigh bone) and tibia (top of the shin bone) during surgery.   Conventional knee replacement procedures require the femur and tibia to be shaped precisely, in order to fit one-size-fits-all jigs.   With a customised jig, unique cutting guides are then created to fit each patient's knee perfectly, said Dr Lee. But first, patients undergo a magnetic resonance imaging (MRI) scan to obtain a 3D model of their knee. On top of the standard cost of the procedure, implants and MRI scans, they also have to pay about S$2,000 more to customise the jig.   Dr Lee added that the technique cuts short surgical time, reducing anaesthesia time, which is why he had recommended Mr Chin to use it for his bilateral knee replacement procedure.   Dr Teo Yee Hong, a consultant at TTSH's Department of Orthopaedic Surgery and head of Service (Adult Reconstruction), said the customised jig may also reduce the risk of bleeding as it reduces some steps in the surgery, as well as improve accuracy and consistency in the surgery performed.   However, Dr Teo added that the general risk of a knee replacement procedure still remains, regardless of the method used.   Dr Lee also recommends PSI for "special-sized people" such as those who are unusually tall or petite.   One such person Dr Lee encountered is Mrs Nancy Tew. At her height of 1.33m, the 61-year-old administrator's petite size meant that conventional knee replacement instruments will not fit her, said Dr Lee.   Mrs Tew, whose osteoarthritis in the left knee was so severe that the pain kept her awake at night, underwent a knee replacement surgery last month. She too had a jig made specifically for her.   "The cartilage in my knee was all worn out and surgery was the only option left. Fortunately for small-sized people like me, there's this new procedure," said Mrs Tew.       WHEN YOUR KNEES GIVE WAY   Osteoarthritis of the knees, a degenerative disease of the knee joint, is more common in older adults.   Our knees bear most of our weight. Wear and tear can occur with age. If you're obese, added Dr Lee, excess weight adds extra stress on the knees and worsens the problem.   For sufferers, the pain from severe osteoarthritis can be unbearable. "This happens when the cartilage in the knee wears out. The bare bone rubs against each other, resulting in friction with every movement," said Dr Lee.   Mrs Tew, who joked that she used to "look like a crab, walking sideways" whenever she used the stairs, said: "I can't even describe how bad my knee pain was before the surgery. The pain felt like it was eating into my bones."   Dr Lee said mild to moderate cases can be treated with supplements such as glucosamine and hyaluronic acid injections which eases inflammation in the joints. When all else fails, surgery is the only option.   "Many people have the misconception that after knee replacement, you end up sitting in a wheelchair for a long time. In the right hands, the success rate of the surgery is more than 90 per cent," said Dr Lee.   For Mr Chin, the final straw came when he realised he was giving up a lot of activities he loved because of his knee problem.   "I could no longer jog, play golf or go out with my family. If I can't even keep fit, I knew it would just get worse," he said.   Just a month after their surgery, Mr Chin and Mrs Tew can walk unassisted and bend their knees - something which they had not been able to do for years before treatment. In another three months' time, Mr Chin will be able to hit the golf range again.   Responding to his friends' wheelchair question, Mr Chin said: "What wheelchair? I was already on my feet the next day!"   Do you really need a custom-made cutting jig for your knee replacement procedure? Dr Lingaraj Krishna, a consultant at the Division of Hip and Knee Surgery at National University Hospital, said NUH does not routinely offer customised cutting jigs to patients unless they specifically ask for it.   "These jigs have the potential to speed up the procedure. However, there is no evidence to suggest that they improve the outcome of knee replacement surgery, as compared to standard or computer-assisted techniques," said Dr Lingaraj.   He added that every surgical technique has its own set of advantages and disadvantages, and that the custom-made jigs are not necessarily safer or less risky than the standard instruments.   "One potential problem is that the positioning of these jigs may be affected by soft tissue variations around the knee. This is because they are made based on bony anatomy alone," he explained.                 This article was featured in Today May 17, 2011. http://www.todayonline.com/Health/EDC110517-0000222/Customised-body-parts