The National Institute for Health and Clinical Excellence (NICE) has issued updated full guidance to the NHS in England, Wales, Scotland and Northern Ireland on individually magnetic resonance imaging-designed unicompartmental interpositional implant insertion for osteoarthritis of the knee.


Osteoarthritis of the knee can cause pain, stiffness, swelling and difficulty in walking. In this procedure, an individually designed implant is inserted at the knee between the thigh and shin bones with the object of realigning the knee and preventing bone-on-bone rubbing. This aims to reduce pain and delay the progression of osteoarthritis and the need for further, more invasive surgery, such as knee replacement.

Coding recommendations

The OPCS-4 classification is used to classify interventions and surgical procedures carried out on the patient, it cannot identify how a type of implant is made.

Insertion of a unicompartmental interpositional implant:

W55.1 Primary prosthetic interposition arthroplasty of joint

Y53.4 Approach to organ under fluoroscopic control (if used)

W71.2 Open excision of intra-articular osteophyte (if performed)

Y76.7 Arthroscopic approach to joint (additionally assigned if osteophyte is removed arthroscopically)

Z84.5 Tibiofemoral joint

Note: It is not possible to define whether the implant was inserted into the medial or lateral side of the tibiofemoral joint.

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