What does my procedure code mean?
If you have private medical insurance, you may have been given a code such as W4210 for your operation. This short guide explains what that code is, why it matters and how to check it.
What is a procedure code?
A procedure code is a short letter-and-number code, for example W4210, that identifies a specific operation or procedure. Insurers use it to authorise your treatment and to process the claims from your surgeon, your anaesthetist and the hospital.
Where you'll see it
You will usually hear or see your procedure code during the pre-authorisation call with your insurer, in letters or emails from your insurer, and on hospital paperwork such as your admission letter.
Why the exact code matters
The code has to match the operation that is actually planned. Similar-sounding operations often have different codes, so a small difference in the plan can mean a different code.
Common differences include:
- First operation or revision. A first knee replacement (W4210) has a different code from a revision, where an existing knee replacement is redone (W4230).
- Partial or total knee. A partial knee replacement (W5200) replaces only one part of the knee, while a total knee replacement (W4210) replaces the whole joint surface.
- One side or both sides. Operating on both knees at once (W4280) has its own code, separate from one knee (W4210).
- Robotic-assisted or conventional. A robotic-assisted knee replacement (W5830) is coded differently from a conventional one (W4210).
- Injections. A joint injection without image guidance (W9040) differs from one given with image guidance (W9030). A hyaluronic acid injection (W9042) and an Arthrosamid injection (W9052) also have their own codes.
Why some codes can't be claimed together
Some procedures are considered part of a larger operation, so insurers will not pay for them separately. For example, a smaller step carried out during a joint replacement is usually included in the main code.
Each code page in the procedure code finder shows the codes that can't be billed with it.
Why my insurer used a different code
Insurers sometimes list their own wording for an operation, or a slightly different code. This does not necessarily mean something is wrong. Your surgeon's secretary and your insurer can confirm the right code before treatment.
If you're paying for yourself
If you are paying for your own treatment, you may still see a procedure code on your quote or invoice. It simply describes the operation you are having.
Look up your code
Type the code or describe the operation to see what it means and which insurers commonly use it.
For guidance only. Always check the code and obtain authorisation from your insurer before treatment. Other insurers may use different codes and coding rules.
Open the full procedure code finder →
Common orthopaedic codes
- W3712Primary total hip replacement – unilateral +/- cement
- W3713Complex primary total hip replacement (including bone grafting or femoral osteotomy)
- W3717Minimally invasive hip replacement - unilateral
- W3780Total prosthetic replacement of the hip, +/- cement, bilateral
- W3714Total hip replacement, +/- cement, after excision arthroplasty or arthrodesis (including conversion of hemiarthroplasty or revision of other previous hip surgery which involved internal fixation)
- W3720Robotic assisted total hip replacement - unilateral +/- cement
- W3721Robotic assisted total hip replacement - bilateral +/- cement
- W5830Robotic assisted total knee replacement – unilateral +/- cement, +/- patella
- W5831Robotic assisted total knee replacement - bilateral +/- cement, +/- patella
- W5820Robotic assisted unicompartmental knee replacement - unilateral
- W5821Robotic assisted unicompartmental knee replacement - bilateral
- W4210Total prosthetic replacement of knee joint +/- cement +/- patella resurfacing - unilateral
- W4200Complex primary total knee replacement (i.e. including bone graft, augmentation or osteotomy)
- W4212Minimally invasive knee replacement +/- cement +/- patella resurfacing - unilateral
- W4280Total prosthetic replacement of knee joint +/- cement +/- patella resurfacing - bilateral
- W5200Unicompartmental knee replacement - unilateral
- W5201Unicompartmental Knee Replacement - bilateral
- W0632Prosthetic patello-femoral replacement (as sole procedure) – unilateral
- W0633Prosthetic replacement of patellofemoral joint - bilateral (as sole procedure)
- W5300Bicompartmental knee resurfacing
- W3715Hip resurfacing arthroplasty
- W3718Minimally invasive hip resurfacing
- W3719Hip resurfacing arthroplasty bilateral
- W3732Revision of uncemented or cemented total hip replacement without adjunctive procedures - unilateral
- W3733Revision of total hip replacement (including insertion of reconstruction rings, plates, screws, etc., and/or impaction bone grafting to acetabulum and/or femur) - unilateral
- W3740Second, third or further revision total hip replacement (excluding acetabular liner and head changes)
- W3944Acetabular liner and head changes
- W37422 stage revision of total hip replacement for infection - first stage
- W37432 stage revision of total hip replacement for infection - second stage
- W3744Robotic assisted revision of total hip replacement - unilateral
- W4230Revision of total knee replacement – unilateral
- W4231Robotic assisted revision of total knee replacement - unilateral
- W4244Tibial liner exchange in total knee replacement
- W42402 stage revision of total knee replacement for infection - first stage
- W42422 stage revision of total knee replacement for infection - second stage
- W5210Revision of unicompartmental knee replacement - unilateral
- W5800Conversion of a unicompartmental knee replacement to a total replacement of knee joint
- W5822Robotic assisted revision of unicompartmental knee replacement - unilateral
- W2830Removal of internal fixation from bone / joint, excluding K-wires +/- image guidance
- W3530Removal of percutaneous wire
- W9040Injection(s) +/- aspiration, into joint, cyst, bursa - unilateral
- W9030Injection(s) +/- aspiration, into joint, cyst, bursa with image guidance - unilateral
- W9045Injection(s) +/- aspiration, into two or more joints, cysts, bursae - bilateral
- W9035Injections(s) +/- aspiration into two or more joints, cysts, bursae with image guidance - bilateral
- W9042Injection of viscosupplement into joint - unilateral
- W9032Injection of viscosupplement into joint with image guidance - unilateral
- W9043Injections of viscosupplement into joints - bilateral
- W9033Injections of viscosupplement into joints with image guidance - bilateral
- W9052Injection of polyacrylamide hydrogel into joint +/- image guidance - unilateral
- W9053Injection of polyacrylamide hydrogel into joints +/- image guidance - bilateral
- W9018Percutaneous biopsy/ arthrography/ aspiration in assessment of total hip replacement
- W9240Examination/ manipulation of joint under general anaesthetic +/- injection +/- arthrogram (as sole procedure)
- W9020Dynamic arthrogram of joint
- W9282Joint fluid examination (e.g. polarising microscopy) performed by consultant (including aspiration of fluid)
Need a hip or knee assessment?
Mr Jakub Kozdryk, Consultant Orthopaedic Surgeon, sees patients with hip and knee problems at Nuffield Health Warwickshire and Circle Meriden Hospital.
For guidance only. Procedure codes and descriptions on this site are provided for general guidance only and are not a guarantee of insurance cover or payment. Always check the correct code with your surgeon's secretary and obtain authorisation from your insurer before treatment. Insurers shown are examples only. Other insurers are available, and each may use the same, similar or different codes and coding rules.