Up until a few years ago, surgeons performing hip and knee replacement surgery struggled with accuracy because they had no perfect image of the replacement area. Alignment of implants could be very hit and miss (one American study suggesting that implants were misaligned in around 50% of cases), with the resulting outcomes not always as satisfactory as they would have liked. Nowadays robot-assisted surgery, three-dimensional imaging techniques and custom-fit implants allow surgeons to be much more accurate.
Surgery, of course, is not necessarily the first option. In some cases counseling patients to alter their lifestyle by changing eating and exercise habits can preclude the need for surgery. Physiotherapy and medication can also be of benefit. But, if surgery cannot be avoided, modern techniques considerably improve the chances of a positive outcome.
Holy Cross Hospital in Fort Lauderdale, Florida has been using MAKOplasty, a robotic arm assisted device since 2006. First using it for partial knee procedures, the hospital began using it for hip replacements in October 2011. The device facilitates the accurate alignment and positioning of implants by feeding a real-time three-dimensional CT scan to the surgeon, allowing him to size and place the socket and femur stem on a computer image before starting the surgery.
Orthopedic surgeons with Baptist Health use the robot technique to assist in resurfacing the knee, a procedure to reduce pain and improve knee function by removing spurs in the joint, so delaying the need for knee replacement surgery. The surgeons also began using the technique around five years ago for partial knee replacement surgery, which can be carried out where only one of the knee’s three compartments (medial – the inside of the knee, lateral – the outside of the knee, and patellofemoral – behind the kneecap) is affected.
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The robot allows them to cut only to pre-determined parameters, meaning that the implant can be properly positioned without being twisted or askew. The operation is smaller, with a smaller incision that facilitates more rapid recovery and reduced rehabilitation. It is possible to recover 100% motion and the implant can last a minimum of 10 years. Robot-assisted partial knee replacement surgery, the doctors say, allows patients to return home after only one night in hospital and most are able to walk unassisted within a week.
They also now use it for hip replacement surgery.
Custom fit implants
Custom fit implants are effectively the next stage along from robot-assisted surgery. Prior to the procedure, a CT scan of the affected area is sent to a company like ConforMis, a Boston-based company that specializes in converting CT data into a precisely engineered implant specific to the individual patient. The fit is exact so recovery is very fast. Of course, each implant is unique and cannot be used for another patient. As yet, the technique has not been applied to hip replacement but that is probably just a matter of time.
The benefits of new technology
According to Dr Raymond P. Robinson, chief of Joint Reconstruction and professor of Orthopedics at the University of Miami Miller School of Medicine, modern techniques used in total knee replacement surgery have resulted in a 97% good or excellent result rate with the best implants lasting 30 years. He warns, however, that new technologies are often introduced with great fanfare but it is often difficult to assess which will actually lead to better outcomes for patients. At the end of the day, once the hype dies away, it is the patient and surgeon who are left to measure the success of the procedure.
A patient’s view
According to one 67-year-old patient who had hip surgery in 1999 and then again on the other hip in 2012, modern techniques far surpass the old methods. After the first operation, he stayed in hospital for five days and faced restrictions on what he could do for months after the surgery. His second operation required only a two-night stay in hospital, he was pain-free and was able to put all his weight on the joint within a week.
In another case, a 96-year-old woman says that one day after her operation she felt better than she did before and in six months was walking independently. She had previously been told that she was too old to undergo the surgery.