Robotic Hip Replacement FAQs

I do not have conflict of interest with any company.  I am not paid by any implant company.  I do not get paid by the company that makes the robot.  I use robot as a tool during surgery, which I feel is helpful for improving the long-term outcomes of my patients.

Individual computer-assisted and robotic software companies have ties with implant manufacturing companies.  Currently the robotic platform does not allow use of any implant with the software available for computer-assisted surgery or for robotic assistance.  As an example, the Mako Robot is associated only with Stryker manufacturing company at the current time.

A robotic system for joint replacement surgery is a significant investment.  If a hospital does not do enough joint replacement surgeries, then it is not a worthwhile investment for the hospital.  Each hospital/hospital system has different leverage for getting the kind of system that they want at their hospitals.

Additional considerations are if joint replacement surgeons at that hospital are interested in working with the technology.  If a joint surgeon is interested, there is additional training that is needed to gain familiarity with the software before performing the procedure on patients.

All insurance that covers traditional hip replacement cover the robotic hip replacement. There should be no additional cost incurred to the patient for using robotics during hip replacement surgery. Nevertheless, it is best to inquire with your hospital if the hospital charges more to do a robotic hip replacement than what is covered by your insurance.

The hospital may decide to charge more for robotic hip replacement because they have to recover cost of equipment and there is additional work involved by the surgical team. The robotic hip replacement does require more work for the surgeon and the assistants. There is preoperative planning involved in robotic hip replacement.

Additional work is needed intraoperatively for placing pins into the pelvis for registration of the pelvis with the computer. the pins in the pelvis need to be removed after the surgery. Additionally, the surgical wound at the pin site needs to be closed. Most of the additional work is intraoperatively, when the surgeon registers the pelvis for the robot to recognize the 3 dimensional geometry of the hip.

There are certain aspects of the surgery which are faster with the robot. As an example, reaming the cup is faster because the planning is done before the surgery and the surgeon can go directly to the reamer of the size chosen for the cup.
However, there are a few additional items that are done in a robotic hip replacement, like placement of the pins into the pelvis, removal of the pins and registration of the bony pelvis that take more time. Typically it takes more time to do robotic hip replacement surgery than a traditional hip replacement surgery.

The surgeon has to do the following things additional for robotic hip replacement surgery:

•  Preoperatively, the surgeon has to plan the surgery from the CT scan that is performed on the patient.
• The surgeon has to look at logistics at the hospital if there are other surgeons using the robot for any surgery so that there is no conflict in operating time.
• The surgeon has to make incision in the pelvis and place pins for registering the anatomy of the pelvis with the robot and to match it with the preoperative CT scan.
• The surgeon has to do registration of the femur and the cup for the robot to recognize the 3 dimensional anatomy.
• After the surgical exposure is made, the surgeon has to place pins inside the pelvis and inside the femur for helping the robot understand that the hip geometry.
• EKG lead has to be placed over the knee before the surgery for helping the robot understand the limb length.
• The pins have to be removed at the end of the procedure.
• The markers from inside the hip need to be removed.
• The wound at the location of the pins in the pelvis has to closed after the pins are removed.

The incision size after hip replacement surgery is exactly the same as traditional hip replacement surgery.  In addition, there is incision over the pelvis for placement of the pins.  I always tell my patients is the “incision is as less as possible as much is necessary”.

Some research has shown that because reaming of the bone is performed only with one reamer, the blood loss is a little less than traditional hip replacement surgery.  Usually, in a traditional hip replacement surgery, we sequentially ream the cup until the needed size is reached. In the robotic hip replacement surgery because we know the size preoperatively.  The robotic arm is attached to the reamer and the surgeon goes directly to the ream size leading to less blood loss that can occur during the sequential reaming process.  This small decrease in operating time and small decreased blood loss in the big picture in my opinion is negligible in my opinion.

There is no decrease in the hospital stay after robotic hip replacement surgery.

My postoperative hip protocol does not change because of hip replacement surgery. It remains exactly the same as traditional hip replacement.

I strictly use the posterior approach if I am using robotic hip replacement surgery.  I feel that placement of markers around the hip need additional exposure if I am using anterior approach to the hip joint. This additional exposure negates the advantages of using the anterior approach for hip replacement surgery.  I therefore perform robotic hip replacements only using a posterior approach.

The surgery using a robot requires additional incision for placement of the pins.  The operative time is little longer because of this and because of the registration process.

The patient does require a CT scan before the procedure, which involves some radiation.

There is an additional risk in complication (although very low) because of placement of pins into the pelvis.  The pins if placed incorrectly into the pelvis, can damage the structures inside the abdomen and inside the pelvis.

There is also the risk of breakage of pins that can cause retention of hardware or can necessitate additional exposure to remove the broken hardware (if the pin breaks).

The surgeon who is in training and is not very familiar with robotic hip replacement may have significantly increased time in the operating room and the patient can be exposed to increased risk of complications that are associated with increased surgical time.

If the surgeon is not cognizant of the anatomy and the location where components should be placed, the components can actually be placed in an incorrect position.  In computer assisted navigation and robotics, I always say “garbage in and garbage out”.  It is very important to give the robot accurate information.

If the information given to the robot is incorrect, then the robot and the computer will give incorrect information for placement of the implants.  It is therefore critical to have a surgeon experienced not only in hip replacement surgery, but also in the working of the robot when choosing a robotic hip replacement surgery.

I have not had that happen as of 2018. However, in a circumstance where the equipment crashes during the case I would proceed with the case as if I was doing a traditional hip replacement.

The robot improves accuracy in component position, accuracy in deciding hip offset and in limb length.  There is slightly decreased blood loss during reaming of the acetabulum.  There is a potential of decreased bone loss because of the accuracy of the how the bone is milled and how the bone surface are prepared.

Research has also shown there is a decrease in radiological outliers.  As of 2018, one study has shown that this improved accuracy due to use of a robot improves patient outcomes in as less as 2 years. This is new technology and we are still gathering long term data.

The materials used in a robotic hip replacement surgery are exactly the same used in a traditional hip replacement.

Very few hospitals have the capability to allow the surgeon to use robot during hip replacement surgery.  Patients wanting robotic procedure, should inquire with the surgeon if their hospital has the equipment for robotic hip replacement surgery.

When you ask the surgeon this question, it would be good idea to inquire if the surgeon is employed by a hospital they operate out of (especially if the hospital does not have a robotic hip).  Employed surgeons cannot operate at hospitals other than the hospital that employs them.

There are certain hospitals, which have the robotic equipment, but will not allow the surgeon to use the equipment procedures.  As example, the hospital may have the robotic equipment, but may allow it to only for partial replacement of the knee and not necessarily to do hip replacement using robotic assistance.

The robotic hip replacement surgery is supposed to improve the accuracy of placement of the prosthesis.  In the hands of a competent surgeon and in the hospital that does a good number of these cases, the hope is that the long-term outcomes and the survivorship will be better than traditional hip replacement surgery.

Traditional hip replacement surgery has been shown to be very predictable in relieving pain from hip arthritis and in restoring range of motion of the hip.  We have long-term results from traditional hip replacement surgery.  Our hope is we can use technology like robotic hip replacement surgery to further improve the outcomes.

Medicare covers for robotic hip replacement and the out of pocket expense for a patient is not more than what the patient would incur for traditional hip replacement.  If the patient has Medicare without a secondary, the patient is responsible for the 20% that Medicare does not cover.  This 20% amount in 2018 is a few hundred dollars and the surgeon’s office should be able to give you an accurate out of pocket expense that will be incurred by the patient.  The Medicare rates change, but the surgeon’s office should have this information.

Hip replacement is elective surgery and there should ideally be no surprises as to what your out of pocket expenses will be for the surgery. Patients are responsible for their deductible, copay and co-insurance. Some commercial insurance companies refuse to tell the provider what the amount of the patient’s deductible.

If a surgeon’s office is unable to tell you your out of pocket expense, you can call your insurance company to inquire about out of pocket costs.  My experience with private insurance companies is that when the patient calls them and informs them, they are working with “out of network” provider, they try to steer the patient away to a doctor who is in their network. The majority of surgeons who provide excellent care in New York are not employed by hospitals and do not participate in most insurance networks.

If the patient has Medicare and a secondary insurance, the secondary insurance will cover the 20%.  The patient may have a deductable with a secondary insurance.  Medicare also has a deductible that is usually met within a few visits to the doctor in the early part of the year.

Hip replacement depending upon the complexity of the case takes about an hour to one and half hours to perform.  If we add robotic assistance, it takes about 15 more minutes to do the procedure.

The indication for hip replacement is hip arthritis and this indication does not change for a robotic hip replacement.

If the patient has anatomical issues that will prevent the placement of pins into the pelvis, the patient cannot have robotic hip replacement.  This could be irregularities or excision of the iliac crest for a graft needed in the past Another contraindication will be superficial skin condition over the pelvis that will preclude placement of pins in the pelvis.  As of 2018, I have not encountered these contraindications.

After a robotic hip replacement surgery, the postoperative rehabilitation is the same as after posterior hip replacement surgery.  In addition, there is a scar over the pelvis where the pins are placed for the robot to recognize the pelvis.  Since there is another incision for the pelvic pins, there is another dressing to take care of in the postoperative period.

No, the incision for placing the pins in the pelvis is relatively very small.  These pins are placed in “percutaneously” (ir thro very small incisions) and the swelling in that extremity will not be different from swelling in a traditional hip replacement surgery. The swelling after traditional hip replacement surgery in the affected extremity lasts for 4 to 6 weeks.  I advise my patient to use compression stockings to control the swelling. Compression stockings also decrease the risk of blood clots after hip replacement.

No, the risks of blood clots are not more after robotic hip replacement surgery.  I evaluate risks of blood clots prior to the surgery.  For patients who are at high risk for developing blood clots or who are a risk of developing pulmonary embolism, I give them stronger anticoagulants in the postoperative period.  For the patient’s with extreme high risk, I use filter so that the blood clot does not travel into the lung from the periphery.

For a vast majority of my patients, I use aspirin as blood thinner after surgery.  In the absence of complicating factors and in patients who are not at high risk for blood clots, I use aspirin after hip replacement surgery as a blood thinner.  The robotic procedure by itself does not change the protocol for prevention of blood clots after a surgical procedure.

The advantage of aspirin is that it acts immediately.  It is associated with less risk of bleeding inside the joint and elsewhere in the body.  It is cheap and it also prevents the risks of heterotrophic ossification (which means formation of bone within the joint) that can lead to joint stiffness.

The pain after a robotic hip replacement surgery is similar to that of traditional hip replacement surgery.  The pain control is started even before the surgery.  I premedicate my patients prior to the surgery so that the pain after the surgery is controlled.  I use regional anesthesia for pain control.  Additionally, I use injection intraoperatively so that the postoperative pain is controlled.  The incision from placement of the pins for robotics has not significantly increased the pain in the postoperative period after a robotic hip replacement.