I-Assist guided Verilast Knee replacement- Knee replacement that lasts for 30 years

October 31, 2014 (MMD Newswire) — Knee replacement in young patients can now last for a long time, thanks to the novel combination of a smart device, ‘I-Assist’ and a durable implant, the ‘Verilast knee’.A procedure involving an I-assist device to implant a Verilast knee, was performed for the first time in the world on a thirty two year old woman in Chennai, India by noted orthopaedic surgeon, Dr.A.K.Venkatachalam.

Case Report-

Ms Payal, a thirty two year lady from Gujarat was suffering from a rare condition called ‘Avascular necrosis’ of the knee and had suffered extensive damage. Although, she was very young for a knee replacement, the extent of the damage left no option for Dr.A.K.Venkatachalam. He had recently introduced the I-Assist device for another patient and was working with Verilast knee technology that had shown to reduce up to 81% of wear as compared to traditional materials.

He decided to go ahead with a knee replacement procedure for Ms Payal using the Verilast CR knee and the I-Assist. It was first time in the world that the I-Assist toolwas used to implant a Verilast knee. The I-Assist tool uses electronic components in a palm sized device. With this, the surgeon can align and validate implant positioning during the knee replacement.

After the procedure, the patient was very happy with the results.

About the Verilast Knee Technology

The durability of the Legion CR knee with Verilast technology is based on laboratory testing.

In a laboratory, the LEGION CR knee with VERILAST Technology was compared with a similar knee made from conventional materials (cobalt chrome and standard plastic). The results showed that after five million cycles, or simulated steps, the LEGION CR knee reduced 98 percent of the wear experienced by the other knee made of conventional materials. After 45 million cycles,it was noted with the LEGION CR knee with Verilast technology, that the wear reduced to 81% in comparison to the conventional knee implant.That’s equal to around 30 years of actual use.

VERILAST technology uses advanced, low-friction surfaces on both sides of the joint, the femur bone of the thigh, and the tibia bone of the leg. It combines Smith & Nephew’s award-winning OXINIUM(TM) Oxidized Zirconium metal alloy and a “cross-linked” plastic component (XLPE), which together has been proved in the laboratory to double the wear of a conventional knee.

OXINIUM(TM), Oxidized Zirconium is a tough, smooth metal with a ceramic surface 4,900 times more abrasion resistant and 20 percent lighter than the cobalt chrome metal used in conventional implants.

- The ceramic surface is created through a manufacturing process where oxygen is naturally diffused into the zirconium metal as it is heated in air. The original metal surface is transformed into a ceramic coating which is integrated with and part of the underlying metal ; It is not an externally applied coating

- With no detectable amount of nickel, the metal most associated with allergies, OXINIUM(TM) is a biocompatible material for implants.

- This proprietary material has been used in more than 250,000 knee implants.

About the I-Assist Smart Tool

‘I-Assist’ is a smart tool designed to improve the accuracy of a total knee replacement. It assists the surgeon in aligning knee implants to each person’s unique anatomy. The outcome is very predictable as perfect alignment is achieved intra operatively and raises the chances of favorable outcomes. Perfect alignment correlates positively with survivorship or durability of the implant.

Which type of knee replacement patients’ benefit most from this combined technology?

It is of great value primarily to young patients undergoing total knee replacement. The durability of a knee replacement is dependent upon the alignment. As younger patients will survive longer after a knee replacement, it is crucial to get the first knee replacement perfectly aligned. There is a correlation between the alignment and survivorship of the implant. This will reduce the need for a redo or revision knee replacement. Revision operations are difficult and expensive.

In addition, a sizeable number of these young patients have additional complications that make a knee replacement difficult. Mal-united thigh and leg fractures secondary to previous accidents rule out the use of traditional instruments. Bony deformities within and outside the knee preclude use of all other modes of instrumentation and navigation.

Before this novel procedure, surgeons including Dr.Venkatachalam used “Patient specific instruments’ and ‘computer navigation’ to implant the Verilast knee. These are not applicable to difficult primary knees with bone loss.

The ‘I-Assist’ system is the only system that allows accurate alignment in these complicated and difficult cases.