Approximately 5-10 % of people fail to recover normally after a significant trauma or injury to a joint (e.g. knee, shoulder) despite superior operative skills and superior and appropriate conventional rehabilitation. These people have an abnormal tissue reaction called "arthrofibrosis". Excessive scar formation within the joint causes persistent or progressive joint stiffness.
When unrecognized or ineffectively treated, joint stiffness due to arthrofibrosis can result in a condition of stiff joints, or stiff knees, and also called adhesive capsulitis, commonly referred to as "frozen shoulders". Arthrofibrosis is often the underlying cause or permanent impairment of normal motion in shoulder, elbow, knee, and ankle accompanied by chronic pain and functional disability.
Practically speaking, frozen joints make it difficult to for people to perform activities or normal everyday life, especially walking, driving, managing their responsibilities at home, and doing their jobs.
Subsequent efforts to correct the problem can be costly to healthcare system and frustrating for the patient at a minimum.
High risk patients who have had major tissue trauma from severe injuries to joints (fractures, dislocations) or surgery (total joint replacement, rotator cuff repair, anterior cruciate ligament reconstruction) should be carefully monitored during the initial phases of conventional treatment to identify lack of appropriate progress. If an abnormal recovery pattern persists despite appropriate physical therapy and a home exercise regimen, more aggressive treatment is required. There are limited options typically used in this sequence:
Forceful physical therapy manipulation and stretching is often the first choice, but sometimes may threaten the integrity of surgical reconstruction or cause painful flare ups and rebound stiffness. Painful physical therapy can also reduce patients' willingness to comply with treatment and prolong their use of narcotics.
Supplementing therapy with a patient-controlled mechanical stretching device for home use can restore range of motion and build patients' confidence in their ability to help themselves - but only if the device is effective and actually used. Low intensity stretch devices are often prescribed and lower cost, but patient compliance and outcomes are questionable for severe motion loss patients. Using a more powerful ERMI device here often avoids the need for any further treatment.
If joint stiffness and motion loss persist, manipulation under anesthesia or surgery to lyse adhesions may be performed. These procedures are costly and can trigger another cycle of trauma followed by abnormal scarring. In 20-25% of cases, the procedures are unsuccessful and more treatment is required.