Robotic Anterior Hip Replacement: Do You Need Both?

No, adding a robot to a hip replacement done through the front does not give you a better hip if your anatomy is normal. The two are sold together because they sell well together. The robot does not change the approach, it does not protect the nerve that the approach passes besides, and it does not make the incision smaller. It earns its place when your anatomy makes measurement genuinely hard: a socket deformed since childhood, an old fracture, a leg already noticeably shorter than the other. This page covers why the two are marketed as a pair, what the robot actually measures, when I use it, and how to decide whether you need either one.

Two things’ patients ask for together

This page exists because patients arrive having read about the anterior approach and about the robot separately and concluded that the two combined must be the best available hip replacement. That is a reasonable conclusion to draw from the advertising. It is not what I would tell you across the desk. Each decision has to be made on its own merits for you, and stacking two marketed features does not multiply the benefit. Sometimes it multiplies the setup time and nothing else.

Why they are marketed as a pair

There is a practical reason and it is not sinister. With the patient flat on their back for an anterior approach, both hips are square to the table and both legs are accessible, which suits an optical tracking system. Some surgeons also find the anterior approach benefits more from measurement, because judging leg length by feel is harder when access to the femur is more restricted.

There is also a commercial reason. Both are premium, marketable features, and a hospital that has bought a robot and a surgeon who has built a practice on an approach have aligned interests in describing the combination as advanced.

Neither reason tells you whether it is right for your hip.

I have made this case on television myself, and I have changed my mind since

In 2016 a television news team filmed me talking about robotic hip replacement, and in that segment I describe the robot guiding the surgeon’s hand and the scan being used to plan the operation in advance. All of that is accurate about what the machine does. What I would add now, several years on, is the part the segment does not cover: when it is worth doing, and when it is not. I am leaving the segment up rather than quietly taking it down, because you are entitled to see where a surgeon has moved and why.

 

The measurement problem the machine is solving

The genuine argument for tracking during an anterior hip is leg length. On your back you can also solve that with an X-ray taken during the operation, which many surgeons do and which is quicker and cheaper.

And you can solve it by physically comparing the two legs, which is what I do. It is one of my reasons for not using a traction table: a table holding one leg in a boot on a bracket makes it far harder to lay the legs together and compare them directly. If the leg is in a boot being pulled by a mechanism, you do need something else to tell you how long it is, and at that point a tracking system starts to look necessary rather than optional.

So part of what is being sold as an advance is a solution to a problem created by a different piece of equipment. I would rather remove the problem.

The nerve does not care that a robot is present

Whatever guides the components, the anterior approach still passes through the interval where the lateral femoral cutaneous nerve runs. That nerve supplies the skin over the outer front of the thigh, and injuring it leaves a numb or tingling patch there. It does not weaken the leg. It troubles some patients for a long time.

A robot does not change that. It does not change the wound at the top of the incision in a patient with a significant abdominal fold, and it does not change the fact that in a wide pelvis the exposure has to lengthen to see the femur properly.

Those were my three reasons for moving away from routine anterior hip replacement, and none of them is addressed by adding a machine. That is the single most useful sentence on this page.

What each of the two things actually changes

Patients often assume the approach and the robot are two versions of the same upgrade. They are not. They act on different parts of the operation, and it is worth seeing that side by side.

What is being decided	Changed by the front approach?	Changed by robotic assistance?
Which muscles are cut or moved aside	Yes. This is the real advantage of the approach.	No. The robot does not choose the route in.
Whether the lateral femoral cutaneous nerve is at risk	Yes. The approach passes beside it.	No. The nerve is where it is.
Where the skin is closed, and whether a fold sits over it	Yes. The incision is at the front.	No.
How much exposure a wide pelvis needs	Yes.	No.
Where the socket and the stem are aimed	Indirectly, through what you can see.	Yes. This is what the robot is for.
Whether leg length can be checked by laying the legs together	Only if a traction table is used, which prevents it.	It supplies a measurement instead of a comparison.
How long the operation takes	Longer, by roughly fifteen minutes.	Adds planning, pin placement and setup time.
Whether a scan is needed before surgery	No.	Yes, for the systems that plan from a scan.

 

Where I would use both together

A slim patient without a wide pelvis or an abdominal fold, who is a good anterior candidate on their build, and who also has anatomy making measurement genuinely difficult: a deformed socket from childhood hip disease, a previous fracture fixed thro the front, or the other hip that had an anterior approach.
That is a real patient and I have operated on that patient. It is not most patients.

The question I ask before adding anything

Does this change what I do, or does it only tell me afterwards that what I did was right?

An instrument that confirms my judgement is pleasant. It is not worth an extra computed tomography scan, extra pin sites, extra setup time and extra open time for a routine hip with normal anatomy. Longer open time is infection risk, and infection is the complication that turns a good operation into a hard year.

When the answer is that it genuinely changes what I do, I use it. That is the entire rule, and it is why I use robotic assistance in deformed sockets and previously operated hips and not in straightforward ones.

What the published evidence shows, including the parts that argue against me

I would rather you saw the whole picture than the half of it that suits my position. The row on operating time is the one that cuts against my argument, and it is in the table for that reason.

Question	What the published work found	Which way it cuts
Does the robot make a knee replacement last longer?	Across Medicare knee replacements reported to the American Joint Replacement Registry between 2017 and 2022, navigated and robotic knee replacement did not improve five-year survivorship compared with conventional technique.	Against the robot. Knee evidence, not hip.
Does the robot place hip components more accurately?	In a pooled analysis of twelve studies covering 1,224 hips, the robot achieved greater cup anteversion and more components within the intended range. Hip scores did not differ meaningfully.	For the robot on accuracy, neutral on how the patient feels.
Does the robot make hip surgery longer or riskier?	A 2025 pooled analysis of the same robotic system in hip osteoarthritis reported better forgotten-joint and Oxford hip scores and more reproducible implant positioning without lengthening surgery or raising complication rates.	Against my operating-time argument. Stated here in full.
Does the front approach recover faster?	Higher hip scores in the first weeks, with no significant difference by twelve weeks or one year in one pooled analysis, and no difference at three months or one year in another.	For the approach early, neutral later.
Does the front approach risk the nerve?	Across seventeen randomised trials and 1,575 patients, nerve injury was about seven times more common with the front approach. The authors note the nerve is sensory and the injury is usually benign.	Against the approach, and this is my first reason.
Does the front approach affect wound healing?	In more than seventeen thousand patients, wound complications occurred in 3.6 percent after a front approach against 2.6 percent after side or back approaches.	Against the approach in patients with a fold.
Does a longer operation matter?	In 17,342 primary hip and knee replacements, longer operative time was associated with a higher rate of subsequent deep infection around the implant.	Why I care about setup time at all.
How long does it take to be good at the front approach?	An analysis of 15,875 hip replacements in the Dutch arthroplasty register put the learning curve at about one hundred cases.	Why who does it matters more than what is used.

 

If this combination is what you want

Then you should have it, and you should have it from somebody who does it week in and week out rather than somebody talked into it. The registry data above puts the learning curve at roughly one hundred cases, which is a fair question to ask any surgeon directly.

I will tell you honestly whether I think your build and your films make you a good anterior candidate, because that part I can help with regardless. If you are, and you want the robot as well, I will tell you where I think it adds something and where I do not, and if you still want it I will help you find a surgeon whose routine practice this is.

I encourage second opinions and I mean it. Nobody should have a hip replaced on the basis of a brochure, including mine.

Questions worth asking whoever operates on you

• How many hip replacements do you do through the front each year, and how many with the robot?
• Do you use a traction table? If so, how do you check leg length during the operation?
• Looking at my films and my build, what specifically makes me a good or a poor candidate for the front approach?
• What will the robot change about my operation that would otherwise be decided by judgement?
• How much longer will I be under anaesthetic because of it?
• If the plan and the anatomy disagree during surgery, which one wins?

My own robotically assisted hip cases

These are the hips where I judged robotic assistance worth the setup. The indications are visible on the films. Every one of them has something on the X-ray that made measurement hard: a deformed socket, a previously operated hip, or two hips being done at once.

 

 

 

 

 

 

Who wrote this page

I am Nakul Karkare. Patients arrive having read about the anterior approach and about robotic assistance separately, and having concluded that the combination must be best. This page addresses that directly.

I have been replacing hips since 1997 and I perform the whole operation.
Commercial interests in these two features

I have no financial relationship with any robotic platform, any implant manufacturer or any maker of anterior approach equipment. On a page about two heavily marketed features at once, that is worth stating plainly.

What I have done with this combination

TO BE COMPLETED BY DR. KARKARE BEFORE PUBLICATION. Fill in: the number of anterior approach hips performed with robotic assistance, over what years, and the indications. If this combination is not part of your routine practice, state that plainly. Numerator, denominator and dates on every line. Nothing rounded for effect.

References

The statements on this page that come from published work rather than from my own practice are supported by the sources below. Where I have said something that departs from a published finding, that finding is named in the text alongside my reasoning rather than left out.

• Navigated and Robotic Total Knee Arthroplasty Do Not Confer Improved 5-Year Survivorship Compared to Conventional Total Knee Arthroplasty: An Analysis From the American Joint Replacement Registry. Journal of Arthroplasty. 2025;40(7 Supplement 1):S130–S139. Digital object identifier 10.1016/j.arth.2025.03.047.
• Loke RWK, Lim YH, Chan YK, Tan BWL. MAKO robotic-assisted compared to conventional total hip arthroplasty for hip osteoarthritis: a systematic review and meta-analysis. Journal of Orthopaedic Surgery and Research. 2025;20:466. Digital object identifier 10.1186/s13018-025-05866-1.
• Llombart-Blanco R, Mariscal G, Barrios C, Vera P, Llombart-Ais R. MAKO robot-assisted total hip arthroplasty: a comprehensive meta-analysis of efficacy and safety outcomes. Journal of Orthopaedic Surgery and Research. 2024;19(1):698. Digital object identifier 10.1186/s13018-024-05199-5.
• Liu R, Zhao Y, Yu Z, Liu C, Sun Q, Nan X. Comparative efficacy of direct anterior approach versus conventional surgical approaches in total hip arthroplasty: a systematic review and meta-analysis of randomized clinical trials. Journal of Orthopaedic Surgery and Research. 2025;20:837. Digital object identifier 10.1186/s13018-025-06227-8.
• Ang JJM, Onggo JR, Stokes CM, Ambikaipalan A. Comparing direct anterior approach versus posterior approach or lateral approach in total hip arthroplasty: a systematic review and meta-analysis. European Journal of Orthopaedic Surgery and Traumatology. 2023;33(7):2773–2792. Digital object identifier 10.1007/s00590-023-03528-8.
• Wang Z, Hou JZ, Wu CH, Zhou YJ, Gu XM, Wang HH, Feng W, Cheng YX, Sheng X, Bao HW. A systematic review and meta-analysis of direct anterior approach versus posterior approach in total hip arthroplasty. Journal of Orthopaedic Surgery and Research. 2018;13(1):229. Digital object identifier 10.1186/s13018-018-0929-4.
• Salmons HI, Larson DR, Couch CG, et al. Surgical approach and body mass index impact risk of wound complications following total hip arthroplasty. Journal of Arthroplasty. 2024;39(9 Supplement 2):S459. Digital object identifier 10.1016/j.arth.2024.03.047.
• Wang Q, Goswami K, Shohat N, Aalirezaie A, Manrique J, Parvizi J. Longer operative time results in a higher rate of subsequent periprosthetic joint infection in patients undergoing primary joint arthroplasty. Journal of Arthroplasty. 2019;34(5):947–953. Digital object identifier 10.1016/j.arth.2019.01.027.
• Peters RM, Ten Have B, Rykov K, et al. The learning curve of the direct anterior approach is 100 cases: an analysis based on 15,875 total hip arthroplasties in the Dutch arthroplasty register. Acta Orthopaedica. 2022;93:775–782. Digital object identifier 10.2340/17453674.2022.4802.

This page describes my own practice and judgement. It is not medical advice for your situation. Please see a physician about your own condition.
Last updated: August 2026.