Scar tissue formation is a normal part of the body’s healing process after any surgical procedure, including those on the knee. When this fibrous tissue becomes excessive and disorganized inside the joint, it leads to a condition called arthrofibrosis. Arthrofibrosis causes significant stiffness and a loss of the knee’s ability to fully bend or straighten, which severely limits mobility. Proactive management of this internal scarring is necessary to restore the full range of motion required for daily activities.
Self-Managed Techniques to Increase Mobility
The initial and most consistent method for managing stiffness involves specific exercises a patient can perform safely at home. Active and passive range-of-motion (ROM) movements are fundamental in challenging the developing scar tissue. A common active exercise is the heel slide, where the patient lies on their back and uses their own muscles to pull the heel toward the buttocks, maximizing knee bend.
To improve the ability to straighten the leg, passive techniques like prone hangs are often recommended, involving letting the lower leg hang off the edge of a bed while lying on the stomach. These exercises apply a low-load, sustained stretch that encourages the scar tissue to elongate over time. Applying moist heat to the knee for 15 to 20 minutes before these stretching sessions can help relax the surrounding soft tissues, making the mobilization more effective.
Patients can also perform basic self-massage directly over the incision site and the surrounding stiff areas once the wound is fully closed. Using circular motions or a gentle “push and pull” technique helps to mobilize the external scar and prevent it from adhering to the underlying muscle and fascia. Following exercise, applying ice therapy helps reduce localized inflammation, preventing a flare-up that could trigger further scarring.
Clinical Interventions and Specialized Therapies
When at-home techniques are not sufficient, a physical therapist provides specialized treatments designed to access deeper adhesions. Manual therapy involves the skilled application of force to the knee joint and surrounding structures that a patient cannot safely replicate on their own. The therapist may perform specialized joint mobilization techniques to stretch the joint capsule and target specific internal adhesions.
A physical therapist will also focus on patellar mobility, ensuring the kneecap can glide correctly, as restricted movement in this area is a common feature of knee stiffness. They may apply deep tissue mobilization to the quadriceps and surrounding soft tissues to break up restrictions that impede the knee’s full range of motion.
Instrument-Assisted Soft Tissue Mobilization (IASTM) utilizes specialized tools made of materials like stainless steel to deliver deeper, more focused pressure than hands can achieve. This technique helps to identify and treat fascial restrictions and scar tissue that have formed in the deeper layers of the muscle and connective tissue. Advanced therapeutic exercises, such as high-load, low-speed stretching, are then used to reinforce the new range of motion gains and build strength in the newly available movement.
Medical Procedures for Stubborn Scar Tissue
For cases where several months of consistent physical therapy and self-management fail to restore adequate range of motion, more direct medical interventions may be necessary. Manipulation Under Anesthesia (MUA) is a procedure performed while the patient is unconscious. The surgeon forcefully moves the knee through its full range of motion, causing the dense internal adhesions to rupture.
This procedure is typically performed within a few months of the initial surgery, as the scar tissue is considered less mature and easier to break up. A successful MUA requires immediate and aggressive physical therapy afterward to maintain the motion gains and prevent the newly broken tissue from reforming into scar tissue. Without this intensive post-procedure rehabilitation, the stiffness can quickly return.
If the scar tissue is too mature or extensive for MUA alone, or if MUA is unsuccessful, an arthroscopic procedure called arthrolysis may be performed. The surgeon uses a small camera (arthroscope) and specialized instruments inserted through tiny incisions to visualize and surgically cut or remove the excessive scar tissue, also known as lysis of adhesions. This debridement targets specific mechanical blocks within the joint, allowing for improved movement.
Recognizing Progress and When to Seek Help
Recovery from knee surgery involves a gradual process, and indicators of progress include a steady, even if slow, increase in the range of motion. Patients should notice a reduction in pain, particularly the sharp, restrictive feeling at the end points of bending or straightening the knee. Functional improvements, such as easier walking, sitting, or climbing stairs, also serve as positive signs that the mobilization efforts are working.
Warning signs that indicate a problem include a sudden and unexplained regression in motion or an early plateau in progress despite consistent therapy. If the knee remains significantly stiff, painful, and fails to approach functional motion goals—such as 110 degrees of flexion—after several weeks, it warrants immediate medical review.
A consultation with the surgeon is recommended if a patient has not achieved satisfactory range of motion after three to six months of intensive, non-operative treatment. At this point, the medical team will assess whether the scar tissue is too dense or mechanically restrictive to be overcome by therapy alone. Considering MUA or surgical arthrolysis then becomes the appropriate next step to prevent long-term functional loss.