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Lysis of Adhesions with Manipulation Under Anesthesia (MUA)

What is the Lysis of Adhesions with MUA?

Adhesions in the knee involves the formation of bands of fibrous scar tissue between the knee components and surrounding soft tissue spaces over time. This is often caused after an injury that occurred during a previous surgery (knee arthroplasty) or following a traumatic knee injury resulting in a medical condition called arthrofibrosis (stiff knee syndrome).

Lysis of adhesions with MUA is a combined surgical procedure involving the break down and debridement of adhesions arthroscopically, and skillful manipulation of the knee joint under general anesthesia. While the lysis of adhesions is performed to treat scar tissue post arthroplasty, MAU takes care of arthrofibrosis (stiffness and poor range of motion).

Significance of the Procedure

The bones and soft tissues of your knee typically have slippery surfaces, so they can move easily against each other without friction. However, adhesions (bands of scar tissue) make the bones and soft tissues stick together leading to limited or loss of joint motion and/or flexion. This results in stiff and painful knee joints. The procedure helps to:

  • Free the joint tissues
  • Reduce joint pain
  • Restore normal function
  • Improve range of motion

The Procedure

Light adhesions can often be treated with physical therapy and/or therapeutic massage techniques. However, if the scar tissue in the knee is extensive, orthopedic surgery such as lysis of adhesions with MUA is required to free the knee joint.

Your surgeon typically uses a standard arthroscope (for visualization and access), arthroscopic (motorized) shaver, arthroscopic ablator and a sharp punch to debride the adhesions.

Just before the procedure, you will be draped in the usual routine fashion after which you are administered general anesthesia. The arc of your knee motion is thoroughly examined.

During the procedure,

  • You will be placed in the supine position with your hip flexed at 90 degrees.
  • Your leg will be held in place to prepare for the manipulation.
  • Slight, steady pressure is applied to the upper tibia until the adhesions break away.
  • The knee is then held in the same position for 20 to 30 seconds.
  • The joint space is accessed for instrumentation using an arthroscopic leg holder.
  • The joint is insufflated and the arthroscope is inserted into the arthroscopic portals.
  • The adhesions are identified and then debrided with an arthroscopic shaver.
  • The arthroscope is removed and knee range of motion is examined.
  • The portals are closed and sterile dressings are applied.

The procedure allows the debridement of adhesions within the defined compartments of your knee.

After Surgery Care and Rehabilitation

After the surgery, you will be allowed to go home the same day or the next day. A passive motion machine or an active-assisted physical therapy is recommended to keep the joint flexing and retard the formation of new adhesions. You may also be asked to use ice on the knee or take pain medication as part of after surgery care and the rehabilitation protocol.

Advantages of the Procedure

  • Reliable and minimally invasive surgical technique
  • Effective in treating a stiff knee after arthroplasty
  • Addresses both focal and diffuse arthrofibrosis
  • Deals with loose bodies and impinging tissue lesions

Risks or Complications

The lysis of adhesions with MUA may cause:

  • Swelling of the knee (initially)
  • Knee muscle soreness (temporarily)
  • Wound rupturing or bone fracture (rarely)
  • Surgery associated infections (occasionally)


It may take you a few days to many weeks to recover from the surgery and depends on the nature of your job.


Lysis of adhesions with MUA is not recommended for older persons and people with:

  • Heart disease
  • Acute arthritis
  • Circulatory disease
  • Osteoporosis (weak and brittle bones)
  • AAOS
  • Boston Children's Hospital
  • New England Baptist Hospital