Regional anesthesia improves outcomes for total knee replacement

The technique not only reduces pain, but allows patients to maintain muscle strength in the leg.

  • Friday, May 3, 2019 11:57am
  • Life
Mathew Nicholls. Photo courtesy of Virginia Mason

Mathew Nicholls. Photo courtesy of Virginia Mason

In 2014, one of my now-retired colleagues, Lyle Sorensen, said to then 57-year-old Seattle resident Mary Lou Hanske, “You definitely needed a new knee,” when she was in the recovery room following total knee replacement surgery.

In the mid-1980s, Hanske injured her left knee while skiing and subsequently developed chronic knee pain over numerous years. As a longtime information technology professional, Hanske’s work requires a lot of walking and stair climbing.

“Despite being able to tolerate the pain for a long time, my knee just gave out one day,” said Hanske.

An appointment in orthopedics and sports medicine the next day confirmed serious deterioration and total knee replacement surgery was scheduled for the following week.

In a study led by anesthesiologist Neil Hanson, physicians found that total knee replacement patients did better when local anesthetic medications were continuously infused into the adductor canal mid-thigh. This continuous nerve block technique not only reduces pain, but allows patients to maintain muscle strength in the leg, which is critical to recovery.

“We found that by infusing the local anesthetic medication in a location that preferentially blocked sensation to the knee, we reduced muscle weakness, controlled pain more effectively and made a shorter hospital stay possible,” said anesthesiologist David Auyong.

On the morning of her surgery, Hanske was prepared with several oral pain medications and a spinal block was administered as her primary surgical anesthetic.

“This approach to pain relief helped me soar through my surgery and rehab,” said Hanske. “The surgery was Dec. 11 and I went home Dec. 14. By Christmas, I was on my bike trainer and was swimming in January.”

Pioneering work

The anesthesiology and orthopedics and sports medicine departments at Virginia Mason were involved in related clinical research and as a result, were early adopters of this relatively new approach to pain relief, starting in 2013. In fact, they have now made it the gold standard for most total knee replacements done at Virginia Mason.

Advancement to continuous pain relief has benefits

Adductor canal block is an improvement over previous blocking techniques because it provides pain relief without any weakness. Femoral blocks were used in the past, which provided good pain relief but reduced or eliminated motor function. They also put patients at risk for falls. With the adductor canal block approach, total knee replacement patients can have pain control and mobilize immediately with full-motor function.

Adductor canal block, along with different types of anesthesia, allows for a rapid recovery and quick return to full motion and function. It also reduces the amount of narcotics that a total knee replacement patient might need, which reduces nausea, constipation and confusion that narcotics can cause.

The approach uses an “indwelling” catheter, which provides three days of continuous pain relief. Other pain-control methods rely on single-shot applications, which only provide 24-30 hours of pain relief.

This technique allows the patient to benefit from three days of good pain relief before the inevitable onset of surgical discomfort. The highest levels of pain after knee replacement surgery occur within the first 72 hours.

The ability of Virginia Mason anesthesiologists to keep joint replacement patients comfortable is evident through patient satisfaction scores for pain control, which are in the 99th percentile.

Our overall goal with the adductor canal block and surgical techniques is to help patients mobilize as normally and quickly as possible. This early mobilization reduces the risk of blood clots, stiffness and other complications that can occur from lying down for extended periods.

Mathew Nicholls is an orthopedic surgeon at Virginia Mason Bellevue Medical Center and Virginia Mason Kirkland Medical Center. He specializes in conditions of the knee, hip and shoulder as well as fractures.