Department of Defense-Funded Research to Answer Question of When to Get Knee Surgery

Combat and sports accidents, automobile crashes or a fall down some stairs can all result in complex knee injuries — complete tears of two or more ligaments in the knee.

Known as multiple ligament knee injuries, they are difficult to treat, and problems after surgery, such as poor healing, stiffness or looseness of the knee, persistent pain and early arthritis can be quite common.

“There are a number of controversies around the best way to treat these injuries,” said James Irrgang, a professor in the University of Pittsburgh’s School of Health and Rehabilitation Sciences. “One of these is ‘When do you do surgery?’ Do you get it right away or do you wait for the pain, swelling and inflammation to subside and then do the surgery?”

Irrgang, who also serves as chair of the Department of Physical Therapy, wants to answer that question. His study will investigate the timing of surgery and post-operative rehabilitation for the treatment of multiple ligament knee injuries and how that affects the time it takes to return to military duty, work or sports.

“This could lead to more optimal treatment that would allow a quicker and more thorough return to prior levels of activity, as well as minimize some of the complications that occur,” Irrgang said.

According to Irrgang, multiple studies have indicated that early surgery for knee ligament injuries may result in better outcomes, but may also be associated with increased joint stiffness. However, delayed surgery may be associated with the inability to repair the torn ligaments, resulting in the knee being too loose. 

No conclusive research exists to determine when surgery should be performed and when rehabilitation should start, Irrgang said.

Irrgang is looking at rehabilitation based on anterior cruciate ligament (ACL) injuries in sports — one of the most common knee injuries. The ACL helps stabilize the knee when turning or planting one’s leg. Standard, evidence-based treatment for ACL tears includes early post-operative rehabilitation. Surgery typically replaces the ACL with a tendon graft that allows for rehabilitation to begin after two to four weeks.

However, surgeons treating other kinds of knee and ligament injuries frequently sew torn ligaments back together. Rehabilitation in these cases typically involves protecting the knee by keeping weight off the leg and substantially restricting knee movement for six weeks, which delays return to activity.

After surgery, patients are frequently limited in performing activities related to military training, work and sports. Return to military duty after knee dislocations has been reported to be as low as 41 percent, according a study published in Arthroscopy Journal, and up to 54 percent, as reported in a study published by the National Center for Biotechnology Information. 

“It’s a difficult process, particularly for those who are highly trained, such as active military personnel or athletes before injuries, to get back to doing those activities,” Irrgang said. “In the military, that’s really important.”

Study details

The four-year project recently received a $4.5 million grant from the U.S. Department of Defense and multiple military sites will take part in the study.

The research will have 24 participating sites in total — five U.S. military, three civilian Canadian sites and 16 U.S. civilian sites. 

Other Pitt researchers involved in the study include Volker Musahl, associate professor of orthopaedic surgery, and Andrew Lynch, assistant professor in the Department of Physical Therapy.

Two studies will be conducted at the same time, which researchers say is necessary to answer the questions of when it is best to do surgery and when it is best to do rehabilitation.

In the first study, 392 individuals with a multiple ligament knee injury will be randomly assigned to early (within six weeks of injury) or delayed surgery (12 to 16 weeks after injury) and early rehab (no restrictions on weight bearing or range of motion) or delayed rehab (no weight bearing coupled with restricted motion for four weeks). This will result in the comparison of four groups: early surgery and early rehab, early surgery and delayed rehab, delayed surgery and early rehab and delayed surgery and delayed rehab. The researchers believe that the combination of early surgery and early rehabilitation will result in more complete and earlier return to pre-injury levels of activity.

In the second study focusing on rehab, 298 individuals with a knee dislocation will be randomly assigned to start early or delayed rehab. 

Subjects in all studies will report their activity and function via internet surveys for 24 months after surgery. 

Researchers will also look at questionnaires that measure knee-related and general health, as well as whether knees are too stiff or too loose, the need for other surgeries and any poor outcomes or complications that might occur.