Total knee replacement can be one of the most grueling orthopedic procedures, its long and painful recovery period oftentimes overshadowing its successful long-term results. But the last two years have seen great improvements in this procedure, from minimally invasive techniques to more durable implants that better approximate the function of a natural knee. Patients are recovering faster than ever, with better overall results. Here's a look at some of the most critical advancements in knee surgery.

Surgical technique
In a standard knee replacement, surgeons make an 8-inch to 12-inch incision at the front of the knee, evert the patella 180 degrees, and cut through the quadriceps muscle and tendon, which control much of the knee's function, to gain access to the knee joint. It typically takes the muscle and tendon months to heal, and it's this healing process that causes much of the pain of recovery.

Minimally invasive TKR uses a much smaller incision - 2.5 inches to 3.5 inches - at the side of the patella, rather than the front. The surgeon then slides under the quadriceps muscle, tendon and patella to access and prepare the knee joint and slide the implant into place.

This procedure is more technically demanding than a standard knee replacement, and the learning curve is fairly steep. Initially, it may take up to twice as long as a standard procedure; surgical time gets shorter as the surgeon becomes more experienced. But the benefits to patients are significant. Because the muscle and tendon are left intact, patients experience less pain and recover knee function sooner.

I perform about 30 of these procedures every month, and my patients generally go home after 2.5 days (as opposed to four days of hospitalization plus a week in an inpatient rehab facility for traditional knee surgery patients). The total recovery period is about six weeks, compared to six months to 12 months with the standard approach.

Instrumentation and implants
To accommodate minimally invasive knee replacements, orthopedic surgery equipment manufacturers have streamlined and miniaturized instrumentation to maneuver through smaller incisions and from different angles. Instead of cutting the femur from the front of the knee, for example, we can now approach the bone from the medial and lateral sides.

Some manufacturers have also modified the implants to make them easier to maneuver through the incisions and position in the knee joint. Even slight modifications can produce changes in outcomes. For example, I recently began using an implant with a slightly truncated tibial keel, which makes it easier to position the components accurately when using a minimally invasive approach.

Manufacturers and surgeons are always working on ways to improve the durability, functionality and user-friendliness of knee implants. Some of the most promising work is currently being done with modular implants, which can be assembled piecemeal in the knee and are less bulky than standard implants. Companies are also working on new biological coatings that may eliminate the need for cement, which most surgeons use to secure the implants into the bone.

Navigational systems that provide a dynamic, real-time map of the patient's anatomy are also showing a lot of promise. These systems are a little like global positioning devices for surgeons, letting them shape the bones and place the implants more precisely. Achieving precise alignment may help the implant last longer and contribute to better outcomes.

Anesthesia and pain control
Post-op pain is the primary reason for hospitalization - if we could ensure sustained pain control in the hours after surgery, many patients could go home on the same or the next day. For now, however, most surgeons prefer to manage immediate post-op pain relief by hospitalizing patients for at least one or two days.

My patients receive epidural anesthesia, which lets those who request it stay awake during the procedure. The catheter remains in place overnight and provides sustained pain control for up to 24 hours after surgery. At home, patients take Percocet for pain control for no longer than a few weeks post-op.

The FDA's withdrawal of Vioxx and Bextra caused us to take a step backward in pain control. We used to start our patients on these medications two days to three days before surgery to reduce the inflammatory cascade and minimize the need for narcotics without impeding blood-clotting ability. Without these medications, we've had to rely more heavily on post-op narcotics.

Very few U.S. surgeons perform these procedures. Surgeons who don't do many knee surgeries might be reluctant to learn a whole new technique; other surgeons might be waiting for longer-term outcomes to see if the technique is indeed comparable to traditional surgery.

Acceptance is the key for minimally invasive TKR to really take off - acceptance by surgeons as well as other healthcare providers, such as perioperative nurses, rehab therapists and home care nurses. Surgeons need to take the lead in helping these professionals understand that these patients don't need lengthy hospitalizations, and they might be candidates for more aggressive post-op therapy to accelerate recovery.