Of all knee injuries, knee dislocations are among the rarest seen by orthopaedic (orthopedic) physicians. They usually happen after a traumatic fall, high-speed car injury or a severe sporting accident. When a knee becomes dislocated, it will look deformed and will become crooked. Patients who suffer from a dislocated knee will experience severe pain in the knee and often have numbness below the knee area.
Sometimes, a dislocated knee will go back into place on its own or with assistance, but this is a very painful process and such a complex knee injury that patients often will need to be put under anesthesia or given a pain block.
Knee dislocations are very serious injuries. It is very important that the vascular and nerve function status be determined at the time of injury. For more severe knee dislocations, a CT angiogram may be needed to determine if a potential popliteal artery injury exists. In addition, up to 35% of knees may also have a nerve injury and this should be carefully evaluated at the time of injury.
Most knee dislocations involve injuries to three or four of the major knee ligaments. These include the ACL, PCL, posterolateral corner, and the medial knee structures (including the medial collateral ligament and posterior oblique ligament). In addition, there may be injuries to the medial or lateral meniscus, the cartilage or even a fracture or patellar tendon injury. It is very important to carefully assess the injury both on history and physical exam, stress x-rays, an MRI scan, and other studies as necessary.
It is well recognized that the outcomes of these surgeries are best in the hands of surgeons who perform them regularly and in large numbers. This is important due to the requirement of having the familiarity with the injury patterns, a well versed surgical team, a good supply of allograft ligaments for reconstructions and other factors. Dr. LaPrade is able to offer all of these components to each patient that comes to him with a dislocated knee or complex knee injury.
In general, the results of a dislocated knee are best if treated within the first 3-4 weeks of injury. Confounding factors that can affect knee dislocations can include whether there has been a popliteal artery bypass surgery, a blood clot, a significant amount of swelling or knee stiffness. Any associated lacerations or abrasions of the knee may also need to be carefully evaluated for the suitability of surgery to help minimize the risk of infection.
While there is some controversy as to whether the surgical treatment of knee dislocations should be staged, when the collateral ligaments are repaired/reconstructed first and then the cruciate ligament reconstructions are performed 6-8 weeks later, we strongly believe all of these injuries should be treated at once and at one surgery if possible.
Dr. LaPrade has a very well-versed surgical team that is very familiar with this technique; the goal during surgery is to complete the surgery in a timely fashion. Dr. LaPrade also strives to have early knee range of motion so there is a lower risk of the need for further surgeries. In fact, most series report a 20-25% need for a second surgery to address stiffness that can happen when the patient does not begin physical therapy exercises immediately after surgery.
Our usual recommended treatment for a complex knee dislocation is to reconstruct the ACL with a patellar tendon allograft, double bundle PCL reconstruction with an Achilles tendon and tibialis anterior allograft, repair with an augmentation of the medial knee structures or to perform a direct reconstruction of the medial knee structures, and to perform a concurrent hybrid repair and reconstruction of the posterolateral corner structures as needed. Our preference is to repair meniscal tears rather than to resect them when possible and to strive to achieve a range of motion of a minimum of 0-90° the first day of physical therapy after surgery.
Knee dislocations are very complex injuries and, in general, there is no “cookbook” recipe to address them. Each individual knee has a unique injury pattern which must be assessed when making a surgical plan. However, a careful assessment, utilization of the clinician’s knowledge base and having the patient work with a well qualified physical therapist and rehabilitation protocol usually gets most patients back to normal activities and, more often than not, to high level sporting activities.
Knee dislocations are serious injuries that may require surgery.
