© Magnific
August 9, 2026
Christine Bürg & Marianne Waldenfels
Robotic assistance promises greater precision in knee replacement surgery – and potentially a faster recovery. But do patients really get back on their feet sooner? Orthopedic surgeon PD Dr. Daniel P. Berthold explains what the evidence shows.
An interview with
PD Dr. med. Daniel P. Berthold
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More than 230,000 artificial knee joints are implanted every year in Germany alone – a figure that has been rising steadily for years. Robotic arm-assisted systems such as "Mako" by manufacturer Stryker have long since made their way into German clinics, including those in Munich, Leverkusen, and Frankfurt. They are designed to make implant positioning more precise, protect the surrounding tissue, and speed up recovery after surgery.
But how much truth is there to these promises? PD Dr. med. Daniel P. Berthold, medical director of OrthoCenter Munich and a specialist in orthopedics and trauma surgery with a focus on sports orthopedics and regenerative orthopedics, offers his perspective on the current state of research.
The name conjures up images of a machine operating independently – a misconception that Berthold is quick to clear up: "The most important point upfront: the robot does not operate on its own. It assists the surgeon in planning and placing the prosthesis more precisely," the orthopedic surgeon explains. "With robotic assistance, the bone cuts and the positioning of the prosthesis can be planned and executed with a high degree of accuracy."
This is the question most patients genuinely want answered – and it is precisely here that Berthold sees the most demonstrable advantage: "Some studies show that patients regain mobility somewhat faster in the first days after surgery, are able to bend the knee sooner, or are discharged from the hospital a little earlier."
That said, he is careful to frame expectations realistically rather than fuel the hype: "These differences are fairly moderate, however, and do not automatically apply to everyone. I would therefore not expect miracles, but rather see the potential advantage primarily in the early recovery phase."
There is a plausible biomechanical explanation for why the first days after surgery in particular tend to benefit: "Thanks to the precise planning and execution of the bone cuts, the prosthesis can be tailored very closely to the patient's individual anatomy. At the same time, unnecessary stress on soft tissues and ligaments can potentially be reduced."
In his assessment, this effect is felt mainly in the short term: "As a result, the knee may be less irritated after surgery, which could have a positive impact in the first few days on, swelling, and mobility. The studies to date suggest that this early advantage is possible; however, in the long term, outcomes often converge again."
If the prosthesis can be positioned more precisely, it seems logical to assume it might also last longer. Berthold tempers this expectation, however: "We hope so – but it has not yet been scientifically proven", says Berthold. "Robotic assistance does allow for very precise positioning of the prosthesis. Whether this precision actually leads to fewer instances of loosening or revision surgeries in the long term is something the studies available so far cannot yet answer conclusively."
This does not mean, however, that patients need to worry about durability being compromised with a conventionally implanted knee prosthesis: "Based on current knowledge, both classically and robotically implanted knee prostheses are, overall, very reliable."
A new procedure naturally raises the question of additional risks. Here, Berthold draws a clear distinction between the general risks of any knee replacement surgery and those specific to robotic assistance. Among the general risks he lists, regardless of the method used:
• Infections
• Thrombosis
• Bleeding
• Restricted range of motion
In addition, robotic surgery involves a few procedure-specific considerations that relate primarily to the additional navigation technology:
• For navigation purposes, small fixation pins often need to be inserted into the bone – very rarely, this can lead to infections or minor bone injuries at those sites
• Some systems require an additional CT scan before surgery
• There are sometimes higher costs and a longer operating time, particularly during the surgeon's learning phase
One point is especially important to Berthold because it is so often overlooked: "The technology supports the surgeon but does not replace them. That is why every surgeon must be able to continue the operation safely at any time without the robotic system."
"In general, rehabilitation does not differ significantly from that following conventional knee replacement surgery," says Dr. Berthold. The timeline remains much the same: "Initial mobilization usually takes place on the day of surgery or at the latest the following day. Many patients then need crutches for two to six weeks. It typically takes several months before the knee is fully load-bearing and muscle strength has been rebuilt."
His conclusion puts the often-cited claim of "faster rehabilitation" in perspective: "While some studies do show a slightly shorter hospital stay or faster mobility in the first few days, I would overall locate the advantages more in the early stages of healing rather than in a significantly shortened rehabilitation period."
When deciding for or against a knee prosthesis, the question of whether a robot is involved should not be the first consideration. Dr. Daniel Berthold: "The most important question to start with is: Is a knee prosthesis actually necessary at this point in time? Symptoms,X-ray findingsand limitations in everyday life should all align.
As a rule, conservative treatment options such as physiotherapy, strength training, or pain management should have been exhausted first." Once this question has been addressed, he recommends asking targeted questions during the consultation:
• Is a partial or total prosthesis advisable – and why?
• How much experience does the surgeon have with this surgical method?
• What results does the clinic achieve in terms of infections, revision surgeries, and patient satisfaction?
• What happens if the robotic system fails during surgery?
• When can I realistically expect to walk again, drive, work, or play sports?
Ultimately, Berthold has a clear priority he wants to communicate to patients: "The decision to have a knee prosthesis should never hinge on whether a robot is used," he emphasizes. "What matters is the right indication, the surgeon's experience, and an individualized treatment concept."
Robotic assistance promises greater precision in knee replacement surgery – and potentially a faster recovery. But do patients really get back on their feet sooner? Orthopedic surgeon PD Dr. Daniel P. Berthold explains what the evidence shows.
Christine Bürg & Marianne Waldenfels
An interview with
PD Dr. med. Daniel P. Berthold
