There has been a tremendous amount of speculation and confusion regarding the horrific knee injury of University of South Carolina running back Marcus Lattimore. The school’s statement Sunday about the injury provided more clarity, but it still left fans questioning his return to football.

“University of South Carolina junior running back Marcus Lattimore suffered a significant impact to the front of his right knee during the Tennessee game on Saturday. The ensuing hyperextension of the knee resulted in injury to several ligaments. There were no fractures or additional injuries, according to team physician Dr. Jeffrey Guy.”

We won’t know the exact nature of Lattimore’s injury and specific surgical treatments for weeks, if ever. Therefore I will not try to predict his timeline or long-term outcome. I do think that it would be helpful to explain multi-ligament knee injuries in general and the outcome orthopaedic surgeons expect for most patients.

There are four major stabilizing ligaments of the knee. The anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) are located in the center of the knee. They provide front-to-back and rotational stability to the knee. The medial collateral ligament (MCL) on the inside and a group of ligaments on the outside of the knee provide side-to-side stability.

Torn ACL and PCL in the intracondylar notch
Torn ACL and PCL in the intracondylar notch

By definition, knee dislocations occur when at least three of these ligaments are torn. In essence, there is little or no connection between the bones, and the tibia can be completely displaced from the femur. Damage to the arteries that provide blood to the leg and foot and the nerves that provide sensation and motor function to the extremity are unfortunately common as well. Tweet about knee dislocations

A tremendous amount of debate exists among sports medicine surgeons as to the optimal methods for treating these injuries surgically. The timing of surgery, one versus two surgical procedures, repairing the ligaments versus reconstructing new ones, and the optimal grafts to use vary from surgeon to surgeon. It’s fair to say that treatment essentially consists of completely rebuilding all of the torn knee structures.

Most knee dislocations result from high-velocity trauma, such as motor vehicle accidents. We have little data to predict outcomes among elite athletes because these are fortunately rare events in sports.

One of the few studies that looks specifically at knee dislocations among elite athletes was performed in Europe. Michael Tobias Hirschmann et al followed 24 athletes who competed at a national or international level in fencing, skiing, basketball, and handball.

The authors found that 19 of the 24 athletes returned to their sports after injury, but only 8 of the 24 returned to their pre-injury level. The biggest obstacles limiting the athletes were continued pain and loss of knee motion. The athletes lost an average of 10° of knee motion, which expectedly would hinder athletic ability.

Many fans have commented that Lattimore’s tremendous work ethic and physical ability might help him overcome this injury better than most patients would. The rehabilitation process is lengthy and painful, so these qualities would certainly help.

Wide receiverThe counter argument, as the authors of the European study point out, is that the nature of the sports itself provides a difficult barrier to overcome. Despite recovering adequate strength and range of motion, which would be acceptable for most of us, the ability to rapidly change directions and perform rotational movement is frequently altered. Returning to top-level sports that require exceptional power and agility is not impossible, but it is very difficult.

Historically, knee dislocations resulted in lifelong debilitation. With advances in arthroscopic surgeries and rigorous physical therapy programs, patients now often return to normal lives. They are able to work, exercise, and function fairly normally. As orthopaedic surgeons, we are happy with these results. But as much as we want to return patients to perfect physical condition, the severity of these injuries makes that outcome challenging to deliver.

Reading between the lines of the USC press release and seeing the alignment of his leg after the tackle, it is reasonable to think Marcus Lattimore suffered one of these knee dislocations. The Gamecocks’ star has a top-notch medical staff treating him. He seems to have a great attitude and support network. Knowing how difficult the surgeries and therapy for these injuries are, I’ll be pulling for him to overcome the odds as much as anyone.

The Dr. David Geier ShowWhy are knee dislocations such devastating injuries? In the Zone segment from Episode 63 of The Dr. David Geier Show.

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Note: The following post appears in a modified format as my sports medicine column in the October 31, 2012 issue of The Post and Courier.