Knee Dislocation

/Knee Dislocation

Description of a Dislocated Knee

A dislocated knee is an uncommon knee injury seen by orthopaedic physicians.

A knee dislocation typically happens after a traumatic fall, high-speed car injury or a severe sporting accident. Sometimes, a dislocated knee will go back (reduce) into place on its own or with assistance, but this is a very painful and complex process patients will often need to be put under anesthesia or be given a pain block to reduce the dislocated knee.

Dislocated knee symptoms include:

  • Physical deformity – crooked appearance
  • Severe pain
  • Numbness below the knee
  • Absent or diminished pulses in some cases

A dislocated knee is a very serious injury. 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 all dislocated knees also have nerve damage; this should be carefully evaluated at the time of injury, mainly for the common peroneal and tibial nerves.

Most dislocated knees 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 articular cartilage, a fracture or patellar tendon injury. It is very important to carefully assess the injury both on history and physical exam – it is also important to obtain x-rays, an MRI scan, and other studies as necessary.

Have you sustained a knee dislocation?

There are two ways to initiate a consultation with Dr. LaPrade:

You can provide current X-rays and/or MRIs for a clinical case review with Dr. LaPrade.

You can schedule an office consultation with Dr. LaPrade.

Request Case Review or Office Consultation

(Please keep reading below for more information on this condition.)

Dislocated Knee Treatment

It is well recognized that the outcomes of knee dislocation surgery are best in the hands of surgeons who perform them regularly and in large numbers. This is important due to the requirement of having a familiarity with injury patterns; a well versed surgical team, and a varied supply of allograft ligaments for reconstruction 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 any complex knee injury.

In general, the results of a dislocated knee are best if they are treated within the first 3-4 weeks of injury.

Confounding factors that can affect a dislocated knee include:

  • Popliteal artery bypass surgery
  • Blood clot
  • Significant amount of swelling
  • Knee stiffness
  • Abrasions or lacerations which may require a delay in surgery

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 discussion as to whether the surgical treatment of a dislocated knee should be staged – the collateral ligaments are repaired/reconstructed first and then 6-8 weeks later the cruciate ligament reconstructions are performed – we strongly believe all of these injuries should be treated at once and in one surgery if possible.

Dr. LaPrade and his team are very experienced in knee dislocation surgery; the goal during surgery is to complete the surgery in an efficient and effective manner. Our usual recommended treatment for a dislocated knee is to reconstruct the ACL with a patellar tendon allograft, double bundle PCL reconstruction with an Achilles tendon and tibialis anterior allografts, 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.

Post-Op

Research shows that 20-25% of patients need a second surgery to address stiffness, this can happen when the patient does not begin physical therapy exercises immediately after surgery. Dr. LaPrade strives to achieve a minimum of 0-90° range of motion on the first day of physical therapy after surgery to lower the risk of future surgery. This has proven to be successful in minimizing postoperative stiffens in our treated patients.

A dislocated knee is a very complex injury and, in general, there is no “cookbook” recipe to address them. Each patient has a unique injury pattern that must be assessed when making a surgical plan. However, a careful assessment, utilization of the physician’s knowledge and having the patient work with a well qualified physical therapist and rehabilitation protocol typically gets patients back to normal activities and, more often than not, to a high level of sporting activities.

Knee Dislocation FAQ

What causes knee dislocations?

It is important to determine the actual pathology with a knee dislocation. A kneecap dislocation is different than a dislocation of the main joint of the tibia, the tibiofemoral joint. The treatment of a kneecap dislocation is different than that for a complete tibiofemoral dislocation.

A complete tibiofemoral dislocation is a surgical emergency. It is important that the arterial supply of the knee and the underlying nerve status are clearly checked. A workup to ensure that an arterial injury is not present is essential, which would include the checking of pulses, obtaining an ankle brachial index, and a CT angiogram (if indicated).

What does a knee dislocation feel like?

Most patients with a knee dislocation have severe pain. They are usually unable to bear weight and their knee feels grossly unstable. If the knee stays dislocated, usually patients have severe pain and are unable to put any weight on their joint. If the knee dislocation self reduces, which can occur in athletic competition, then the knee will feel very unstable and most patients would only be able to take a few steps before they would collapse

What prevents knee dislocations?

Most knee dislocations are caused by a significant trauma, so prevention is very difficult. For sports-related knee dislocations, making sure that one is appropriately rehabilitated after an injury, or has excellent baseline strength, can minimize one’s risk of a knee dislocation. In traumatic dislocations, such as a fall from a height or a motor vehicle accident, it would be difficult to prevent a knee dislocation.

How to prevent a knee dislocation again?

Prevention of a tibiofemoral dislocation would depend upon an appropriate workup for the artery and blood supply and then having surgical treatment. After this, ensuring that one has a maximal return of strength and stability as well as possibly using a knee brace would minimize the risk of a recurrent tibiofemoral dislocation. These are quite rare.

The prevention of a kneecap dislocation depends upon an appropriate workup to determine the risk of redislocation, as well as obtaining appropriate post-dislocation rehabilitation. Patients who have a high-riding kneecap or have a relatively shallow trochlear groove, have a higher rate of kneecap dislocations, even with proper rehabilitation. However, the rate of redislocation is still less than 50%, so following a proper rehabilitation program would be indicated in these patients.

Can a knee dislocation occur when sitting cross-legged?

It would be very difficult to have a tibiofemoral knee dislocation occur when sitting cross-legged.

However, if one does have a high-riding kneecap and a very flat trochlear groove, then a lateral patellar dislocation could theoretically occur when sitting cross-legged. In most circumstances this would be very rare, but it could occur with patients who have had repeated dislocations of their knee cap previously.

Can a knee dislocation happen when kneeling?

It would be highly unlikely that a tibiofemoral or a patellar dislocation would happen when kneeling.

What is the recovery time for a dislocated knee?

It is commonly felt that a tibiofemoral knee dislocation should be operated on rather than treated with a brace or casting. This type of treatment was performed about 20 years ago, and has since been demonstrated in systematic reviews to not have good outcomes. Therefore, it is generally felt that a dislocated knee should have a single-stage multiligament reconstruction. The recovery time for this can be quite long, varying from 9-15 months in some circumstances. This can be dependent upon the patient’s age, their overall weight, and if there are other injuries, such as meniscal tears, cartilage injuries, or fractures, which can significantly affect one’s recovery from a knee dislocation surgery.

NOTICE: Effective June 1, 2019, Dr. LaPrade will be practicing at Twin Cities Orthopedics in both the Edina and Eagan Minnesota Clinics and Surgery Centers

Learn How We Can Help You Stay Active

Request a Consultation