Newswise — ANN ARBOR, Mich. - It can happen from a check in a hockey game, or a fall from a ladder while cleaning out the gutters. There’s usually a ‘pop’ and instant pain in the knee.

Knee dislocations can happen a variety of ways,” says John Grant, M.D., Ph.D., an assistant professor of orthopaedic surgery and sports medicine at Michigan Medicine. “Most patients incur the injury from some sort of trauma, such as a fall from a ladder, a car accident or playing a sport, while others could experience it in a low velocity way from their daily activities while living with obesity.”

Grant says surgery is typically necessary to treat the injury. But should it be done immediately after the injury happens?

A new clinical trial aims to find out.

Early or delayed surgery

“There are pros and cons to operating on the injury early, or waiting several weeks after the injury takes place to operate,” says Grant, the primary investigator of the Michigan Medicine trial site.

“In this clinical trial we are assigning patients to two groups: one group that has surgery within six weeks of the injury taking place, or the other group which has a delayed surgery that takes place 12 to 16 weeks from the date of injury.”

Grant says there are positives and negatives to both early and delayed operation.

“Previous research suggests overall stabilization of the knee is better when you perform surgery right away,” he says. “But, that early surgery comes with the negative side effect of the patient being at higher risk for experiencing significant stiffness after the surgery.”

He explains that delaying surgery can result in a flip of those outcomes.

“If you let the swelling and inflammation of the injury go down, the risks of stiffness after surgery are much lower, and the patient is less likely to need a second surgery to treat that stiffness,” Grant says. “But the suggestion from previous research is that the overall stability of the knee may not be quite as good in this delayed surgery fashion.”

Grant says this clinical trial will be the first to directly compare the outcomes in both situations.

“There can be a lot of variability to the pattern of injury in the knee,” he says. “It’s difficult for one person to study because you don’t see enough of the same type of injury to do these direct comparisons.”

He adds, “With this being a 29 site, Department of Defense sponsored clinical trial, the ability to enroll and study these injuries in greater amounts is easier, and can greatly contribute to the research around this subject.”

Examining rehabilitation timing

After trial enrollees are randomized for early or delayed surgery, they go through another randomization for rehabilitation following surgery.

“This trial is also allowing us to examine the rehabilitation protocols post-surgery,” Grant says. “Typically with these surgeries, surgeons are relatively conservative on how much weight the patient should bare afterward so that the ligament reconstructions don’t stretch out prematurely. But we’re examining if they need to be conservative, or if there is a benefit to weight bearing right away.”

Participants will be randomized to early rehabilitation, which means they will begin progressing to full weight bearing one-week after operation, and delayed rehabilitation, which will begin weight bearing at four weeks after surgery.                   

“Once again this has pros and cons,” Grant says. “If you get them moving early, the graft could stretch out, but if you don’t, the muscles could waste away and the patient could experience stiffness. Which, like I mentioned earlier, could require another surgery to reduce that stiffness.”

Enrolling patients

Grant and his research team are currently enrolling patients for the trial.

“We’re looking for male and female patients, 16 to 55 years of age, that have recently experienced a major injury to two or more ligaments in the knee,” he says. “Our team is happy to see the patient to determine their eligibility, and orthopaedic surgeons who might not be comfortable taking the patient down the surgical reconstruction path could certainly refer them to us to be seen.”

He also notes that patients who missed the opportunity to be enrolled in the surgery timing portion of the study can still be eligible and enrolled in the rehabilitation portion of the study after their surgery.

Grant says the primary outcome for the trial is to better understand how long it takes patients to return to their pre-injury activities, such as work, sports and daily life.

“This clinical trial will allow us to better understand the optimal timing of surgery and rehabilitation in knee dislocations,” Grant says. study identifier: NCT03543098.