Background: Combat and sports injuries as well as automobile accidents can result in complex knee injuries involving tears of two or more major ligaments. These are referred to as multiple ligament knee injuries or knee dislocations. Other structures like nerves, blood vessels, tendons and bones may also be injured. Because of the severity, knee dislocations are difficult to treat and problems after surgery can be quite common. Problems may include poor healing, the knee being too stiff or too loose, persistent pain, and early arthritis. After surgery for knee dislocations, individuals are frequently limited in performing activities related to military training, physical labor and sports. Return to military duty after knee dislocations has been reported to be as low as 40% and is much lower than the reported return to work for civilians.

Experts agree that surgery is necessary after knee dislocation, but they do not agree on:

Very little high-quality research exists to answer these questions. Early surgery for knee dislocations may result in better earlier return to activity, but may also be associated with increased joint stiffness. Delayed surgery may be associated with the knee healing, but it also may result in the joint being too loose.

The best evidence for when to start rehabilitation is based on isolated ACL injuries, where early post-op rehab is the standard. However, unlike ACL surgery which typically replaces the ACL with a tendon graft, surgeons frequently sew torn ligaments back together after knee dislocation. Therefore, rehab after surgery for a knee dislocation typically involves protection of the knee by keeping weight off the leg and not allowing the knee to move very much for 4 to 6 weeks, which delays return to activity.

Without good evidence for when to do surgery and when to start rehab, a large scale clinical study is needed to improve the outcomes for these devastating injuries.

Objective: The overall purpose of this project is to determine when it is best to do surgery (within 6 weeks of injury or 3 to 4 months after injury) and when to start rehab (immediately or 4 weeks after surgery) for the treatment of knee dislocations. We will investigate how long it takes to resume pre-injury military duty, work, and sports as well as how individuals are performing in their lives after surgery.

Study Design: We will recruit military personnel and civilians between the ages of 16 and 55 with a knee dislocation. We will exclude individuals that have major injury to a blood vessel or other body part that prevents them from having knee surgery or participating in rehab. We will conduct two studies at the same time. Two studies are necessary because there are major questions about when is the best time to do surgery and when to start rehab, but some surgeries need to happen right away and some surgeries should be delayed to let the person recover from other major injuries. To make the best decisions, we also need to determine when it is best to start rehab when the timing of surgery is predetermined.

In Study 1, we will randomly assign (like flipping a coin) 392 individuals with a knee dislocation to early (within 6 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 and only limited motion for 4 weeks), resulting in the comparison of four groups: Early Surgery & Early Rehab, Early Surgery & Delayed Rehab, Delayed Surgery & Early Rehab, and Delayed Surgery & Delayed Rehab.

In Study 2, which is to determine when it is best to start rehab in those that can not be randomly assigned to knee surgery, 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. Our main interest is the time it takes to return to pre-injury military duty, work and sports. We will also look at questionnaires that measure knee health and general health, as well as whether knees are too stiff, too loose, the need for other surgeries and poor outcomes that might occur.

Military Benefit and Clinical Impact: Knee dislocations dramatically impact our military’s combat readiness and often lead to individuals having to leave the military early. This project provides a unique opportunity to determine the best time to perform surgery and when to start rehab for individuals with a knee dislocation.

After this study, we will gain better understanding of how to shorten the time needed to return to military duty, work and sports. Additionally we will learn the best way to minimize bad outcomes commonly associated with this injury, namely stiffness, or sometimes looseness, persistent pain and arthritis in the long term. This will help to improve military readiness and decrease adverse outcomes and health care costs associated with knee dislocations. This study is relevant to the military because it targets an important problem for the military, involves military personnel as subjects and investigators and addresses the soft tissue trauma surgical care and PT/OT rehabilitation focus areas in the 2016 PRORP funding opportunity.