Managing Stiffness After Knee Replacement

Even when knee replacement surgery is successful, stiffness in the knee joint can remain. People with a stiff knee after surgery may be unable to fully straighten the leg, to bend the knee, or both. Fortunately, there are ways to get rid of knee stiffness.

This article explains the causes of stiffness after knee replacement surgery and the treatments that are used to relieve it and restore normal range of motion in the knee.

Causes of Stiffness

In some people, knee motion can be difficult to regain after surgery. Lack of normal motion after knee replacement can be due to one of several causes, or a combination of causes. Lack of normal motion may be caused by:

• Inadequate pain control
• Poor motion before surgery
• Excessive scar formation
• Improper positioning of the implants
• Other surgical complications

Inadequate Pain Control

Pain control after joint replacement is usually a manageable problem. But in some people, this can be quite difficult. Some patients find the side effects of pain medication impossible to tolerate. But a lack of adequate pain control can lead to difficulty increasing the motion of the newly replaced joint.

It is important to partner with your healthcare provider to develop a pain treatment plan that works for you.

Poor Motion Before Surgery

When trying to predict the likelihood of stiffness after a knee replacement, the most important thing to consider is how well you can move your knee before having surgery. People who have stiff knees heading into knee replacement surgery are more likely to have stiff knees after the operation.

There are steps that can be taken at the time of surgery to help release tight ligaments and tissues around the joint. These methods can also help remove any damaged pieces of cartilage or bone that are interfering with movement. But sometimes the flexibility of the tissues is limited to a point that cannot be fully corrected.

Excessive Scar Formation

Some people seem to naturally make more scar tissue than others, a condition known as arthrofibrosis. Some situations may also cause more scar formation. Arthrofibrosis affects 3% to 10% of patients who have undergone total knee replacement.

Improper Positioning of the Implants

Surgeons make an effort to balance the knee at the time of surgery. This means finding the proper size and alignment of the knee replacement so that the knee joint is not too tight and not too loose. The goal is to make this balancing the same whether the knee is straight or bent.

This is precisely why a knee replacement is a difficult procedure. In fact, the art of perfecting this takes many years. Errors in the positioning of an implant may not be apparent on the operating table and may only become noticeable when the patient is slow to recover from surgery.

Other Surgical Complications

Complications of surgery often lead to other problems. Patients who experience joint replacement infections, complex regional pain syndrome, or other complications have a higher chance of developing stiffness.

Treatment

After knee replacement surgery, it is important to work with a physical therapist to restore as much range of motion as possible. Typically, the range of motion will progress quickly during the first three months. It can continue to increase for up to two years following surgery.

The range of motion of the replaced knee can be improved with a combination of stretches, exercises, and gradual resumption of normal activities. Some surgeons will recommend the use of a machine to bend the knee, called a CPM (continuous passive motion).

Treatment of stiffness after knee replacement depends on how long it's been since surgery and the cause of the stiffness. The usual treatments for stiffness include the following approaches.

Aggressive Physical Therapy

Physical therapy is a useful treatment for a stiff knee, especially within the first three months after knee replacement. Physical therapy can also be considered after this time, but the results are not as good as early physical therapy.

You will be prescribed exercises that target different muscle groups, encourage aid in maintaining joint mobility. These may include such as quadriceps sets, heel slides, leg raises, and various knee-straightening exercises.

A type of splint called a dynamic splint has also shown some encouraging results when used in conjunction with physical therapy.

Manipulation Under Anesthesia

In a manipulation, a patient is given general anesthesia, usually through an IV. A surgeon forcibly moves the knee to break up scar tissue. This procedure is most beneficial in the six to 12 weeks after surgery.

Surgical Removal of Scar Tissue

Surgical removal of scar tissue after knee replacement is seldom performed but may be helpful in some rare circumstances. The results of removing scar tissue have not been particularly good at improving motion. Healthcare providers usually consider other treatments first.​

Revision Knee Replacement

When all other options fail or the knee replacement parts are not positioned well and can't be repositioned, it may be necessary to perform a revision knee replacement. The bone cuts and the size of the new replacement can be modified to help allow for better knee motion.

Summary

Surgeons perform knee replacement surgeries to repair worn-out knee joints that are causing severe arthritis. Even if a surgery is successful, however, you can still end up with complications, including knee stiffness.

Treatment options include aggressive physical therapy, manipulation under anesthesia, surgical removal of scar tissue, and revision knee replacement. Your surgeon will decide which treatment is best for your unique needs.