Second opinion says my knee might suit a partial but he won't decide until he's inside. Is that normal or a red flag?

Promised an update after the August second opinion, and I've got one, but it's raised a question I didn't see coming.

Different hospital, different surgeon, fresh X-rays including one standing up which the first place never did. He went through it properly and said the wear is nearly all on the inner side, the outer side looks reasonable, the ligaments felt fine when he pulled the leg about, and that I might be a candidate for a PARTIAL rather than a full replacement. Smaller op, keeps more of my own knee, quicker to get going. Sounded great and I was nodding along.

Then he said he'd consent me for BOTH, and that the final decision would be made on the day once he could actually see the inside of the joint, because sometimes the other side turns out worse than the pictures suggest. He also mentioned he does the partials with a robotic arm, which I didn't ask about because by then my head was full.

So I got home and the doubt set in. Is "I'll decide when I'm in there" normal, or does it mean he's not sure what he's doing? Am I going to wake up not knowing which operation I've had? And is the partial actually a proper fix or is it the budget version that I'll be back for in ten years? After six months of being told "not yet" I'd like to be pleased about this and I'm not managing it.

Normal, Brian. Word for word what mine said, consented for both. I went to sleep hoping for a partial and woke up with a total because the outer side was worse than the X-ray let on. I'll admit I was a bit thrown for a day. Nobody had done anything wrong, they'd just seen more than the film could show.

Not a candidate myself, both sides of both knees, so I'm asking on your behalf as much as anything. The bit I've never understood is why a partial is supposedly the quicker recovery if you still end up on crutches and doing the same bending exercises. Is it actually a smaller operation or does it just sound like one?

And the robot thing. Two of the private hospitals near me have big adverts about it now and I can't tell whether it's a genuine step up or the surgical equivalent of a car with go faster stripes. Would be good to hear from Mr Henderson before Brian pays extra for one.

Brian T said:

Is "I'll decide when I'm in there" normal, or does it mean he's not sure what he's doing?

It is normal, and it is the mark of a surgeon being careful rather than uncertain. The direct answer is that a partial knee replacement can only be confirmed once the joint is open, so consenting for both and making the final call in theatre is standard practice, not a hedge.

Here is why. A partial (unicompartmental) replacement resurfaces only the one worn compartment, in your case the inner or medial side, and leaves the healthy cartilage, the bone and, crucially, the ligaments alone. That only works if three things are true: the wear really is confined to that one compartment, the anterior cruciate ligament is intact, because the partial relies on it for stability, and the deformity is modest enough to correct. A standing X-ray and an examination get you most of the way there, which is what your second surgeon has done, and it sounds like he has done it well. What imaging cannot reliably show is the state of the cartilage on the outer side and under the kneecap, or the true condition of the ligament. Those are confirmed by looking. If the outer compartment turns out to be worn, a partial would leave arthritis behind and you would be back within a few years, which is exactly what he is trying to avoid by keeping the total on the consent form. Maureen's experience is the common one when that happens.

To Pete's question, it is a genuinely smaller operation: a shorter incision, less bone removed, and no ligaments sacrificed, which is why people often get going faster and why many say the knee feels more like their own afterwards. But the milestones do not change much. Both take about 1 to 2 hours, both mean 1 to 3 days in hospital, and both involve walking aids for 2 to 6 weeks, most normal activities within about 3 months and full recovery over 6 to 12 months. The bending exercises matter just as much. The trade-off sits on the other side of the ledger: partials carry a slightly higher chance of needing a revision than totals, because arthritis can spread to the compartments that were left alone or the smaller implant can loosen, and if that happens it is converted to a total. Both types have around 90 to 95% of implants still in place at 10 years and typically last 15 to 20 years or more, so a partial is not a budget version. It is a different bet, keeping more of your knee in exchange for a somewhat higher chance of a second operation, and the site sets that out in detail in the guide to partial versus total knee replacement.

On the robotic arm: positioning a partial implant accurately is technically demanding, and mispositioning is one of the reasons partials get revised, so this is where robotic guidance was first widely adopted and where it makes the most sense. The consistent evidence is that it places the components more accurately and more consistently than hand-held instruments. What it has not yet shown is a knee that lasts longer or satisfies more people, because the long-term data is not old enough. The surgeon's experience still matters far more than the tool, and the article on robotic-assisted knee replacement gives the fuller picture, including the small extra risks and the cost.

Two questions worth taking back to him: how often, in his hands, a planned partial becomes a total on the day, and how many partials he does a year. Whether your knee is one of the ones that suits a partial is a judgement for the person who has examined it and will be looking at it in theatre, not for a forum, but from what you describe you are being handled properly.

Reading this with my own first surgical appointment finally booked for October, after the referral some of you talked me into over the summer. "Consent for both" and "how often does the partial become a total" are going straight on my list. Brian, being pleased and being frightened at the same time seems to be the standard state on this section of the forum.

Rang his secretary with the two questions. Answers: roughly one in ten of his planned partials becomes a total on the day, and he does "a good number" of partials, which I'll pin down properly at the pre-op appointment rather than on the phone.

I'm on his list. No date yet, likely early in the new year. And I've stopped reading the partial as the cheap seats and the total as the failure. It's the knee that decides, and I'd rather he saw what was actually in there than promised me something from a photograph. First time in a year I've felt like the thing is moving.