Knee dislocations or multi-ligament knee injuries are very severe injuries where the bones that make up the knee become dissociated due to violent trauma. Dr. Robert Marx was part of a panel of experts discussing multi-ligament knee injuries at the American Academy of Orthopedic Surgeons, in New Orleans, March 2014. Some of the following issues were addressed by the panel.
Classification of multi-ligament knee injuries by level of energy of the injury
The trauma can be high energy (such as a motor vehicle accident), moderate energy (sports, such as a tackle in football) or low energy (such as an obese person who falls over a low speed). Usually at least two of the four knee ligaments are injured, but three or all four can be disrupted.
When is emergency surgery needed for a knee dislocation?
In most severe cases, the knee may be obviously dislocated and require reduction where the doctor realigns the bones to put the knee “back in joint”. An irreducible knee dislocation is when the knee cannot be reduced and in that case emergency surgery is necessary. Other indications for emergency surgery for a knee dislocation include an open injury or an injury to the artery that supplies blood to the leg.
Multi-ligament Knee Reconstructive Surgery
When multiple ligaments in the knee are torn, the knee is usually unstable for daily life and most patients will opt for surgery. Surgery generally involves reconstruction of the ligaments using tendons taken either from the patient or from a donor. The new ligamentsare fixed in the patient using screws and other devices to make sure they are rigidly fixed. Multi-ligament knee reconstruction is technically complex and requires extensive rehabilitation post operatively for full recovery. In some cases, specifically involving the lateral knee ligaments, the common peroneal nerve can be injured and result in problems walking due to foot and ankle weakness. Some of these patients will have spontaneous recovery over time, but others will not and in such cases further surgery may be required to address their “foot drop”. Dr. Marx generally uses allograft or transplant tissue for multi-ligament reconstruction because multiple grafts are required and it is not ideal for the patient to have so many grafts harvested from their own body. Fortunately, with good surgical technique and rehabilitation, a full recovery is often obtained, with some patients returning to their sport.