Weekly Medical Conference: Posterolateral Corner Injuries

Hey guys,

Broncos_MD here. I’m a non-operative sports medicine physician. I used to make posts on here years ago to educate Broncos fans on various injuries and expected prognosis/recovery. I took a break to focus on my training and establish my early career.

I happen to find a lot of time on my hands so I’m jumping back in to post!

So on we go: Posterolateral Corner (PLC) Injuries

WHAT IS IT?

The [PLC](https://prod-images-static.radiopaedia.org/images/408160/88b03258cb01d15e6870cb206a811e_big_gallery.jpeg) is a complex of structures that provide important stability to the knee joint. It’s actually an extremely complicated anatomic complex consisting of muscles, tendons, and ligaments. The role of the PLC is primarily to provide rotational stability to the knee joint.

HOW DOES IT GET INJURED?

Most commonly, there is a pretty big collision that causes a PLC injury. These collisions consist of a hard blow to the front of the knee, towards the inside. The force gets transmitted to the back/outside (posterolateral) aspect of the knee and causes the injury. Major knee dislocations can also cause PLC injuries (as well as injuries to a whole bunch of other structures). However, this is unfortunately not always required to injure the PLC. Even non-contact rotational/hyperextension trauma can injure the PLC.

HOW IS IT DIAGNOSED?

As with all medical conditions, a good history and physical examination come first. Witnessing the knee injury and seeing the nature of it (contact v non-contact, rotational force, hyperextension, etc) can be really helpful to rule in or out a PLC injury. Physical examination will usually show a knee effusion (a swollen knee filled with fluid i.e. blood). Patients can have varying degrees of pain, with most patients not able to bear weight fully. Athletes can always surprise you- the adrenaline from the game can allow them to play through/push through A LOT.

The other thing to note about the physical exam is that docs can do something called the [dial test](https://orthofixar.com/wp-content/uploads/Dial-Test.png). As imaged, this consists of “dialing” the patient’s knee while they’re laying on the exam table on their front. A positive test is when there is 10 degrees or more of outward turning of the injured knee compared to the uninjured side.

If there is enough suspicion for a PLC injury, patients will get an X-ray and MRI. X-ray is usually negative, but sometimes can show an occult fracture. MRI is diagnostic of PLC injuries in addition to ACL, PCL, and meniscus/cartilage injuries.

HOW IS IT TREATED?

Mild injuries without significant tearing of the PLC can be treated non-operatively with protected bracing followed by rehab.

More severe injuries in athletes, and especially those with a concomitant ligamentous injury (PCL/ACL) require reconstructive surgery by a skilled ortho sports surgeon.

WHAT’S THE PROGNOSIS?

PLC injuries are really difficult to rehab back from. Generally speaking, most sports surgeons in the U.S who do PLC/ACL reconstruction are PHENOMENAL, but orthopedic practice hasn’t perfected outcomes with PLC reconstruction. It’s not easy to perfect align the surgery with native tissue and get that similar rotational stability/confidence back. Additionally, I would say rehabbing back from a PLC injury is an extra layer of complication compared to a vanilla ACL reconstruction. I’d say Javonte would be back to high-ish level activity in about 6 mos, and could potentially be field-ready by this time next year, but I’d almost want to set the expectation to take next year off as well to give him the best chance at coming back to close to pre-injury levels. PLC injuries for skilled position players are straight up bad news. The agility, cutting, footwork, etc really place a lot of strain on the structure and it’s hard to get that stuff back post-operatively. Careers have ended due to PLC injury.

WHAT’S THE LATEST EVIDENCE?

[This](https://pubmed.ncbi.nlm.nih.gov/26260464/) systematic review highlights the relatively high failure rate in patients undergoing surgery for combined PLC and concomitant ligamentous (PCL/ACL) reconstruction. On the brighter side, [this](https://pubmed.ncbi.nlm.nih.gov/24794571/) publication indicates that return to sport is “possible most of the time” in combined PLC/ACL injuries, but there is suspicion that people don’t get to pre-injury performance levels.

I’m happy to answer any questions in the comments. Thanks guys.

DISCLAIMER: I am not a physician employed by the Denver Broncos organization. All of my medical opinions I have shared are purely my own and do not reflect the opinions of any of my colleagues or employer. All information I have provided are meant to be purely educational and I freely admit that I gain no monetary value in creating these threads. Please do not ask me for personal medical advice as I do not have a physician-patient relationship with you and will not be able to provide you with sound medical judgement.