For the first time in Delhi, a hospital Monday began knee replacement surgeries with the aid of computers that minimise the risk of technical failures.

"Even in the US hardly 10 percent of the average 1,200 patients a day who undergo knee replacement surgery benefit from computer-aided surgery although it reduces the chances of bad alignment requiring revision surgeries," said Rajeev K. Sharma, an orthopaedic surgeon at the Indraprastha Apollo hospital.

Trained by leading French orthopaedic surgeon Jean Louis Briard, Sharma Monday performed the first computer navigated knee arthroplasty on a 54-year-old woman from Agra.

The patient, who underwent the surgery that took about 15 minutes more than the conventional method, had almost stopped walking due to arthritis in her right knee.

"The computer navigated system, which cost around Rs.10 million, helps both the surgeons and the patients," Sharma told.

In computer-aided surgery, the doctor benefits from the directions received on the basis of the patient's bone profile registered on the computer with the help of infrared rays and sensors.

On the basis of the bone profile, the computer guides the surgeon on the shaping of the knee bone as per the patient's requirement.

"The possibility of mal-alignment is reduced significantly. Up to 75 percent of the revision knee surgeries are said to be because of technical failures like improper bone cuts or instability of knee or fixating failures," said Sharma, who has been in the profession for two decades.

Computer-aided knee surgeries, which are still a relatively new technique, reduced such possibilities. Reduction in failure rates helps to improve the longevity of implants as a lot of factors influence the success rate.

In India over 12,000 patients undergo total knee arthroplasty every year, while in the US the number is 325,000.

Apollo Indraprastha, which charges about Rs.180,000 for a conventional knee replacement surgery, is currently maintaining the same charge for computer-aided surgery but with the promise of better results, said Sharma.