Manipulation Under Anaesthesia for Knee Arthrofibrosis

Manipulation Under Anaesthesia, commonly known as MUA, is often the first intervention recommended to patients with a stiff knee after surgery. But what does this procedure actually involve, and what are the risks? In our latest interview, IAA founder Kayley Usher sits down with Dr. Ralph Rosenberger, an orthopaedic surgeon in Austria who specialises in arthrofibrosis and revision knee surgery, to discuss why patients should think carefully before agreeing to a manipulation.

What is a Manipulation Under Anaesthesia?

During an MUA, the patient is placed under anaesthesia and the surgeon forcefully bends the knee with the aim of tearing through scar tissue to improve range of motion. As Dr. Rosenberger explains, the surgeon can typically hear and feel the tissues tearing during the procedure. While the patient feels no pain during the manipulation itself, the consequences can be serious.

The risks of MUA

Dr. Rosenberger does not perform manipulations, and his reasoning is clear: the tearing of tissue during an MUA is indiscriminate. When force is applied to break through scar tissue, it is also applied to everything attached to that scar tissue, including tendons, nerves, blood vessels, and even bone. Complications he has personally seen include lesions to the patellar tendon and quadriceps tendon, avulsions of ligaments and the joint capsule, hemorrhage, and in many cases more pain and less mobility than before the procedure. The risk is even greater for patients who have had a total knee replacement. The metal stem on the tibial component introduces additional stress at certain points, increasing the risk of fractures. This risk is compounded in patients with osteoporosis or osteopenia due to inactivity, which is common in people living with arthrofibrosis.

Why repeated manipulations are not the answer

The IAA regularly hears from patients who have undergone multiple MUAs. Dr. Rosenberger's perspective is straightforward: if the first manipulation was unsuccessful, why would a second or third lead to a better result? In fact, the risk increases with each subsequent manipulation, as structures that may have sustained minor damage during an earlier procedure become more vulnerable to rupture.

The inflammatory cycle

Kayley Usher explains the biology behind why manipulations so often fail. Arthrofibrosis is a condition of dysregulated healing, where the body's inflammatory and healing responses do not switch off as they should. A manipulation creates a new wound inside the knee, with significant bleeding that is not cauterized or controlled. This bleeding is a powerful trigger for more inflammation, which in turn drives more scar tissue production, adhesions, and contractions. The result is that many patients quickly lose whatever range of motion was gained during the procedure, and some end up worse than before. This is a critical difference between MUA and a surgical lysis of adhesions. During an arthroscopic lysis, a skilled surgeon carefully cuts the scar tissue in a targeted way and cauterizes the bleeders before closing the wound. This controlled approach significantly reduces the inflammatory response compared to the uncontrolled tearing and bleeding of a manipulation.

The importance of proper assessment

Dr. Rosenberger emphasises that every patient with arthrofibrosis requires a thorough analysis before any intervention. For patients with a knee prosthesis, this means precise measurements of implant position, including the anterior and posterior offset of the femur, the rotation of the femoral and tibial components, the joint line level, and overall limb alignment. If the implant position is unfavourable, no amount of manipulation or lysis will resolve the problem. The implant position must be corrected.

A gentler alternative

For patients where implant position is favourable but mobility is poor, Dr. Rosenberger recommends an arthroscopy with careful lysis of adhesions, keeping the surgery as minimal as possible. Key principles include avoiding the use of a tourniquet unless absolutely necessary, using a radiofrequency cauterizing tool rather than a mechanical shaver to control bleeding, and following surgery with daily gentle passive movement using a CPM machine to reduce the risk of new adhesions forming.

Making informed decisions

Recent research from the University of Nottingham has documented the lived experience of patients who have undergone MUAs, finding that patients generally expected the procedure to resolve their issues, but for many the experience did not match expectations and outcomes were often poor. If you or someone you know has been recommended a manipulation for a stiff knee, we encourage you to discuss the risks thoroughly with your surgeon and ask whether an arthroscopic lysis of adhesions might be a safer alternative.

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https://www.youtube.com/watch?v=7dN5OIohNm0

Arthrofibrosis is a controversial subject and the views expressed by the clinicians do not necessarily represent the views of the International Arthrofibrosis Association (IAA).

The materials presented on this channel are provided voluntarily as a public service. It is of a general nature, based on the scientific literature. The information and advice provided is made available in good faith but is provided solely on the basis that readers will be responsible for managing their own assessment of the matters discussed herein and that they should verify all relevant representations, statements and information. Please consult your doctor.