Robotic and Computer-Assisted Surgery

Part of The Joint Replacement Guide — Phase 4: The Operation · Article 27 of 44 · Hip & Knee

Key Points

Conventional hip and knee replacement remains the established standard, supported by decades of clinical experience and long-term implant-survival data.
Robotic and computer-assisted systems are optional tools that can help a surgeon reproduce a planned implant position more consistently.
The surgeon—not the machine—makes the decisions, performs the operation and remains responsible for the result.
Robotic systems may improve certain measurements on postoperative imaging, but they have not consistently produced meaningfully better pain relief, function, complication rates or implant survival.
A robot cannot compensate for inappropriate planning, poor surgical judgement or limited experience.
Not using robotic assistance does not mean that an operation is less accurate, less personalised or of a lower standard.

What These Systems Actually Do

Computer-assisted and robotic systems provide additional planning and measurement tools during joint replacement.

Some use a CT scan taken before surgery to construct a three-dimensional model. Others create a model during the operation by mapping points on the bone. Tracking equipment then monitors the position of the bones and surgical instruments.

Navigation systems display measurements for the surgeon. Robotic systems may also guide a cutting instrument or restrict it within a planned boundary.

Despite the terminology, these systems do not independently perform a hip or knee replacement. The surgeon exposes the joint, assesses the anatomy and soft tissues, chooses the plan, prepares the bone, inserts the components and checks the result. The surgeon can change the plan or stop using the system if necessary.

Conventional Surgery Remains the Benchmark

Hip and knee replacements were performed successfully for many decades before robotic systems became available. Conventional instruments have produced the long-term results on which modern joint replacement is built.

Traditional surgery is not surgery performed “by eye” or without planning. It uses:

preoperative clinical assessment and X-rays;
established anatomical landmarks;
purpose-designed alignment and cutting instruments;
direct visualisation and feel of the bone and soft tissues;
repeated checks of component position, stability and movement; and
the surgeon’s training, judgement and accumulated experience.

These methods allow an experienced surgeon to adapt to findings during the operation. They remain safe, reproducible and appropriate for the great majority of routine hip and knee replacements.

What the Evidence Shows

The most consistent advantage of robotic assistance is a reduction in variation around a chosen radiographic or alignment target. In other words, the components may be positioned closer to the computer’s plan and there may be fewer measurements classified as outliers.[1–3]

That is a technical finding—not the same as demonstrating a better result for the patient.

Current studies have not consistently shown clinically important improvements in:

pain relief;
walking and everyday function;
patient satisfaction;
complication rates;
recovery time; or
the likelihood of needing revision surgery.

Some studies report small early differences in individual scores, while others find no meaningful difference. Where a statistical difference exists, it may be too small for patients to notice.

The evidence also varies between systems. A result obtained with one platform should not automatically be applied to every device marketed as robotic surgery.

Accuracy Is More Than One Number

A component can be positioned very close to a computer plan, but the quality of the result still depends on whether the original plan was appropriate.

For knee replacement, there remains debate about the ideal alignment target. A robot can accurately reproduce mechanical, kinematic, restricted kinematic or functional alignment, but it cannot determine which philosophy is best for every patient.

For hip replacement, cup inclination and rotation are important, but they are not the only determinants of outcome. Stability, leg length, hip offset, fixation, bearing choice, soft-tissue tension and avoidance of complications also matter.

Greater precision around one measurement should therefore not be confused with greater quality across the whole operation.

Experience and Surgical Judgement

Robotic technology provides measurements, but it does not replace the surgeon’s ability to interpret the patient’s anatomy, balance the soft tissues or respond when the findings differ from the plan.

Conventional surgery allows an experienced surgeon to combine:

formal preoperative planning;
anatomical landmarks;
calibrated instruments;
direct assessment of bone quality;
tactile feedback;
ligament and soft-tissue balance; and
stability testing throughout movement.

These are not imprecise substitutes for technology. They are the established clinical skills on which successful joint replacement continues to depend.

A surgeon should use the technique with which they can most consistently and safely deliver a well-planned replacement. Switching to an unfamiliar platform purely because it is marketed as more advanced would not necessarily benefit patients.

My Usual Practice

I perform hip and knee replacement using established conventional techniques rather than robotic assistance.

This is a considered surgical practice, not an absence of planning or precision. I use preoperative imaging, established anatomical landmarks, purpose-designed instruments and direct assessment of stability, alignment and soft-tissue balance during the operation.

Robotic assistance can be a useful tool in the hands of surgeons trained and experienced in its use. However, current evidence has not shown that it is necessary to achieve an excellent joint replacement or that it consistently produces better outcomes than well-performed conventional surgery.

Patients should therefore feel reassured that conventional surgery remains an established, evidence-based approach with extensive long-term results.

Possible Disadvantages of Robotic Assistance

Depending on the system, robotic surgery may involve:

a preoperative CT scan and additional radiation;
extra tracker pins placed into the bone;
a small risk of pin-site fracture or infection;
longer operating time, particularly during adoption;
technical or registration errors;
interruption or conversion to conventional instruments if equipment fails;
platform-specific training and a learning curve;
restriction to particular implant systems;
additional costs and consumables; and
greater dependence on commercial hardware and software.

These do not mean robotic surgery is unsafe. They show that the technology has its own trade-offs and should not be presented as an improvement without qualification.

The NICE Position

NICE currently allows six robotic technologies to be used in the NHS during a defined evidence-generation period.[1] This is a conditional recommendation while further information is collected—not confirmation that robotic surgery is clinically superior or that it should replace conventional surgery.

NICE found that alignment was generally more precise with robotic assistance. However, the available evidence did not show that this produced better patient-reported or clinical outcomes. NICE identified continuing uncertainty around quality of life, resource use, revision rates and cost-effectiveness.[1,4]

This balanced position is important: robotic technology is promising, but its additional value over established conventional surgery has not yet been proved conclusively.

Availability and Marketing

Robotic systems are expensive and are not available in every NHS or independent hospital. Some providers promote them as a distinguishing service.

Terms such as “precision,” “personalised,” “robotic” and “advanced technology” can be reassuring, but none guarantees:

a pain-free result;
a faster recovery;
more accurate surgery in every respect;
fewer complications; or
a longer-lasting replacement.

Patients should be cautious about comparisons based on marketing language rather than direct evidence of outcomes that matter to them.

Not being offered robotic surgery does not mean that you are receiving an outdated or inferior operation.

What Matters More Than Whether a Robot Is Used?

Important determinants of a successful replacement include:

choosing the right operation for the right patient;
realistic expectations;
appropriate implant selection;
careful surgical planning;
accurate bone preparation;
component position and fixation;
soft-tissue balance and joint stability;
infection and blood-clot prevention;
rehabilitation; and
the experience of the surgeon and wider clinical team.

Robotic assistance may support some of these tasks, but it does not replace them.

Questions You May Wish to Ask

Rather than asking only whether a surgeon uses a robot, useful questions include:

Why are you recommending this particular operation?
Which implants do you use, and what is their track record?
How do you plan and check component position?
How do you assess stability and soft-tissue balance?
How experienced are you with your usual technique?
What outcomes should I realistically expect?
If robotic surgery is proposed, what patient benefit is expected in my individual case?
Would the expected result be different with conventional surgery?

In More Depth

The central question is not whether robotic systems can reproduce particular measurements more consistently. The evidence generally suggests that they can.

The more important question is whether this additional technical consistency produces better outcomes than an experienced surgeon using established conventional methods. That has not yet been demonstrated consistently.

Long-term implant survival is already very good after conventional hip and knee replacement. Proving that a newer technology improves on those results requires large numbers of patients and many years of follow-up.

Until that evidence matures, robotic assistance should be presented as an optional surgical tool—not as a prerequisite for accurate, personalised or high-quality joint replacement.

This article provides general information and does not replace individual clinical advice.

References

National Institute for Health and Care Excellence. Robot-assisted surgery for orthopaedic procedures: early value assessment. HealthTech guidance HTG743. Published 17 April 2025. NICE recommendations.
Mert Ü, Khasawneh MY, Ghandour M, et al. Comparative efficacy and precision of robot-assisted versus conventional total knee arthroplasty: a systematic review and meta-analysis of randomized controlled trials. J Clin Med. 2025;14(9):3249. doi: 10.3390/jcm14093249.
Bensa A, Pagliazzi G, Miele A, Schiavon G, Cuzzolin M, Filardo G. Robotic-assisted total hip arthroplasty provides greater implant placement accuracy and lower complication rates, but not superior clinical results compared with the conventional manual approach: a systematic review and meta-analysis. J Arthroplasty. 2025;40(7):1921–1931. doi: 10.1016/j.arth.2024.12.014.
National Institute for Health and Care Excellence. Robot-assisted surgery for orthopaedic procedures: committee discussion. HealthTech guidance HTG743. Published 17 April 2025. NICE committee discussion.

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