"Dr. Akinbo, my knee won't bend." Stiffness as a cause of failure of total knee replacement

This is the fourth in a series of posts discussing causes of failure of total knee replacement.

          Primary total knee replacement surgeries are usually performed to help people with end-stage degenerative changes of their knees get rid of pain and return to a more active lifestyle. Knee replacement surgeries are generally successful and represent one of the most successful procedures in orthopedic surgery and medicine in general. However, knee replacements can fail. Knee replacements can fail from a myriad of reasons. The fourth cause of total knee replacement failure to be discussed in this series is stiffness. 

          Total knee replacement stiffness can result in a painful knee and be a source of significant dissatisfaction. There are various definitions of a stiff total knee replacement. The most common definitions include knee range motion of less than 75 degrees, and flexion less than 90 degrees. The typical patient with a stiff knee cannot accomplish certain tasks comfortably such as climbing stairs, or rising up from a low chair as one needs about 90 degrees of knee motion to comfortably climb stairs and about 100 to 105 degrees to rise up from sitting in a low chair. 

          There are certain pre-operative risk factors for developing a stiff knee following knee replacement that can be identified prior to surgery. Poor range of motion before surgery is a significant risk factor as pre-operative motion tends to predict post-operative motion. Other risk factors include post-traumatic knee arthritis, prior knee surgeries, prior history of stiffness, and a history of poor pain control. Intra-operative and post-operative risk factors for developing a stiff knee include improperly positioned knee replacement components, oversized knee replacement components, knee instability, knee loosening, knee infection, and significant pain limiting appropriate knee range of motion exercises. 

          The evaluation of a stiff knee would often include a history and physical examination and review of radiographs. Establishing the cause of a stiff knee is imperative when deciding on surgical management. This would involve understanding the pre-disposing risk factors, knowing the intra-operative range of motion obtained, and analyzing the radiographs and other laboratory work-up.

          The treatment for a stiff knee is usually begun conservatively with physical therapy and knee bracing when indicated. Acutely stiff knees following surgery will often respond to a period of physical therapy with focus on range of motion exercises. However, some knees will not respond to this non-surgical measure. For acutely stiff knees following knee replacement, if no improvement with a few weeks of physical therapy, a manipulation under anesthesia (manually breaking up scar tissue under anesthesia) can be performed with return to physical therapy. This is typically performed before 3 months to decrease the risk of complications from the procedure and to maximize gains. After more than 3 months out, consideration is given to arthroscopic lysis of adhesions (knee scope to break up scar tissue in the knee) and return to physical therapy.

          For chronically stiff knees not responsive to non-surgical measures, revision surgery can be indicated. An infection will need to be ruled out as infection can be present even in the setting of knee stiffness. Revision surgery for stiffness requires careful planning, and depending on the cause of failure/stiffness, could range from removing the scar tissue in the knee to removing the scar tissue and going down a size in the plastic to removing all the components and performing a revision/re-do knee replacement. 

          One must understand the goals of the patient before embarking on re-do/revision surgery. Some patients might be painless, satisfied, well-functioning and well-adjusted with a stiff knee. These patients do not necessarily need a re-do/revision surgery. For the dissatisfied patients with a chronically stiff knee, understanding the cause of stiffness is imperative as the failure rate can be significant if revising a knee without an understanding of what caused the stiffness. The goal of knee revision surgery for stiffness is to restore range of motion and decrease pain (if present). This usually results in improvement in functioning. 

          If you have a bothersome or stiff knee replacement, call Hays Orthopedic Institute at 785 261 7599 to schedule an appointment with Dr. Akinbo.