Study finds older knee replacement designs to be just as effective as newer models

Older knee replacement designs are just as effective as newer models – according to new research from the Norfolk and Norwich University Hospital and University of East Anglia.

A new study published today in the journal BMJ Open compares the effectiveness of two established knee replacements.

Eighty osteoarthritis patients, who received total knee replacements in 2018 and 2019, took part the CAPAbility study – a blinded randomized controlled trial run by researchers at NNUH and UEA.

The study found no difference in outcomes between the Genesis II and Journey II BCS knee implants six months after surgery.

Iain Mcnamara, Consultant Orthopaedic Surgeon at NNUH and an honorary professor at UEA, led the research.

The lack of difference between implant designs is important for patients, surgeons, healthcare providers and implant companies. For the patient and surgeons, reassurance can be gained that older designs, with proven track record of function and survivorship, can provide the same patient-reported and functional outcome as more modern designs."

Iain Mcnamara, Consultant Orthopaedic Surgeon at NNUH and Honorary Professor at UEA

The study is the largest published total knee replacement comparison to date and patients will be reviewed three and five years after surgery.

Prof Mcnamara said: "For healthcare providers, older implants are often less expensive and, in the absence of clinical benefit with and demonstrable longevity, the additional expenditure on more modern designs could be avoided.

"The future of design and innovation may come in the form of more modern surgical techniques such as robotic-assisted implantation to assist in placing the knee in a more kinematically sympathetic position which in turn may allow the newer design philosophies to positively influence outcome."

The team are planning future research looking at the effectiveness of robotic technology in knee replacement surgery.

'Comparison of the Journey II bicruciate stabilized (JII-BCS) and GENESIS II total knee arthroplasty for functional ability and motor impairment: the CAPAbility, blinded, randomized controlled trial' is published in the journal BMJ Open on Friday, January 6, 2023.