Knee replacement is overall a very safe procedure. However, there are some associated risks that patients should be aware of. The biggest risks that can occur after knee replacement are infection and stiffness.


Infection is an uncommon occurrence after knee replacement. However, when it does occur, it is very disruptive to the patient's life. Treatment of infection around a knee replacement usually requires removal of the knee replacement, installation of an antibiotic knee replacement for 3 months, and later, a third operation to put a new permanent knee replacement back in place.

We take several steps to prevent infection before, during, and after surgery, and the University of Maryland is a leader in research into the prevention and treatment of knee infection.


Stiffness is another uncommon but possible complication associated with knee replacement. Most patients who undergo knee replacement are not able to fully straighten the leg before surgery. In general, knee replacement allows them to straighten the leg all the way. After knee replacement, most patients are able to bend the leg to the same degree as they were able before surgery. However, knee replacement does not usually provide increased knee bending. Some patients form exuberant scar tissue and have less motion with the knee replacement than they did before the operation.


Instability is one of the main reasons to have a knee replacement. In most cases, the stability of the knee replacement is better than that of the preoperative arthritic knee. However, some patients have instability after knee replacement or develop it over time and need to have the knee replacement redone to improve its stability.

Incomplete Relief of Pain

Although knee replacement is very effective at relieving pain, between 5% and 10% of patients who undergo knee replacement still have pain afterward. This can be as minimal as occasional pain on cold days or pain with climbing stairs or level walking. It is important to understand that the vast majority of patients are very happy with the pain relief, but there is a small subset of patients who have persistent pain after knee replacement.

Nerve and Artery Damage

The knee is surrounded by major nerves and arteries, and it is possible that they could become injured during surgery. With the worst injuries, the patient can lose the leg. Fortunately, this is very rare, and specific steps to avoid it are taken during surgery.

Medical Complications

Medical complications associated with knee replacement surgery are uncommon but include blood clots in the lung or leg, heart attack, stroke, and even death. These risks are minimized by optimizing the patient's weight and medical status before the operation in conjunction with the patient’s primary care doctor.

The above-mentioned risks are all very rare, but it is important to know that they are possible.


Some risks are associated with knee replacements, and it is important to be aware of them. However, in general, the risks rarely occur, with the exception of incomplete relief of knee pain. Approximately 5% to 10% of patients who undergo knee replacement experience incomplete relief of knee pain. The vast majority of patients are happy they had the procedure.

Only the patient can decide when he or she is ready for knee replacement. In most cases, knee replacement is an entirely elective procedure that can be done in the patient’s time frame. There usually is no rush to having the operation. The one exception to this is the patient who is starting to fall frequently because of an unstable knee. Patients who have knee arthritis and are starting to fall because of the knee arthritis should strongly consider surgery.

In summary, knee replacement is an extremely successful operation that has helped millions of patients. Knowing the risks, benefits, and options will help you to be included as part of the care team and will help you to get the most out of your knees.

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To make an appointment with an orthopedic specialist, call 410-448-6400.