Tommy Doyle’s Knee Injury

Tommy Doyle’s Knee Injury
ORCHARD PARK, NEW YORK - AUGUST 12: Tommy Doyle #72 of the Buffalo Bills on the field before a preseason game against the Indianapolis Colts at Highmark Stadium on August 12, 2023 in Orchard Park, New York. (Photo by Timothy T Ludwig/Getty Images)

After working over nearly the past year to recover from a season-ending injury, Tommy Doyle suffered yet another stroke of bad luck when he went down with a left knee injury against the Pittsburgh Steelers Saturday night. 

Doyle suffered a left leg injury early in the third quarter when he was taken down by a Steelers DL, hyperextending his knee. The foot got caught in the turf which forced his knee to hyperextend before he turned off to his right, grabbing the outside portion of his leg.

Unfortunately, Doyle received the worst news possible when the team reported that he had an ACL, LCL, and foot drop as noted below.

This injury comes after Doyle tore his right ACL in the Week 3 loss to Miami last season. He worked his way back to be ready this season only for an injury last week to scare him and then this injury to end the comeback. 

Doyle is looking at a long road with recovery especially after he just got off the merry-go-round that is rehab. Below are details about the injury, concerns, and path moving forward for Doyle’s career.

The Anatomy

The ACL is a ligament that connects the tibia to the femur and runs medial to lateral — or inside to outside — acting as a stabilizer in the knee to prevent the femur from shifting too far forward over the tibia during movement. It also assists in preventing hyperextension in the knee. When the knee is loaded during activity such as cutting and sudden stops, the ACL is designed to keep the knee stable, but in the presence of injury, the ligament is overloaded which either stretches and partially tears or fully tears based on the activity. It is possible to live a normal lifestyle with an ACL-deficient knee, but nearly impossible to resume a high level of play post ACL tear without reconstruction as an adult.

Roughly 70 percent of ACL tears are non-contact in nature in the general population.

Tears also occur with hyperflexion or hyperextension of the knee. In the event of ACL rupture, the knee buckles and there is usually immediate swelling, tenderness, loss of ROM, and pain. Risk factors include but are not limited to gender, age, playing surface, level of play, biomechanical variances, previous injuries to the knee, equipment, and environmental conditions.

LCL Injury

The LCL or lateral collateral ligament is the ligament stabilizing the outside portion of the knee. This prevents the knee from moving out into a varus position. For good measure, the knee also has the PCL which is in the same area as the ACL but goes the opposite way, and the MCL, acting as the medial stabilizer of the knee. 

Mechanism of Injury

LCL tears along with ACL tears are the result of a posterolateral corner injury seen in multi-ligament tears. These types of injuries can happen in a variety of ways, but Doyle’s was the result of a forced hyperextension and varus positions of the knee, bowing outward.

Other structures are typically damaged including, but not limited to the biceps femoris attachment and popliteus, but it is unknown if he has that associated damage. Reports indicate that he is suffering from foot drop which implies damage to the peroneal nerve.

Breaking it down simply, the hyperextension ruptured the ACL whereas the forced hyperextension along with the varus component injured the LCL and also damaged the peroneal nerve.

Foot Drop

The peroneal nerve, also known as the common peroneal nerve allows the foot to perform dorsiflexion, or raising your foot upward. The nerve branches off the sciatic nerve and wraps around the head of the fibula as seen in the picture below. This is also in the area where the LCL attaches. Peroneal nerve damage occurs 15-29 percent of the time when there is an associated posterolateral corner injury. 

Foot drop is a result of the damaged nerve, but depending on the extent of the damage and where dictates whether the function can return. If the function is unable to be recovered, wearing an ankle-foot orthosis (AFO) is indicated to help keep the foot in a neutral position. During walking, this allows the person to push off the toe and the neutral foot position helps prevent the toes from dragging due to the lack of dorsiflexion.

Types of Peripheral Nerve Injury

When the hyperextension/varus position occurs, this can stretch the nerve out and cause a peripheral nerve injury. There are three types of nerve injuries that range in severity: neuropraxia, axonotmesis, and neurotmesis.

Neuropraxia is the mildest form of nerve injury where there is stretching or compression to the nerve, but no structural damage. 

Axonotomesis is where there is damage to the axon and myelin sheath. Think of the myelin sheath as the outer covering of an electrical cord, but the axon is the actual wire inside. 

Neurotmesis is when there is a complete disruption to the entire nerve where there is severing or near complete disruption of the connection. 

While we don’t know the severity of the nerve injury, the hope is that Doyle has neuropraxia. The body can heal this without surgery and can resolve it on its own. This presents as a foot drop but improves as the nerve heals. If he has worse damage, then things could take even longer or heal or they might not at all. Surgeons have options at their disposal to heal the area for function including nerve grafts, but we have no way of knowing the severity. 

Return to Play/Performance

Multi-ligament injuries are tough to come back from in the NFL. According to research, only 55.6 percent of players who suffer an ACL + PCL/LCL injury return to play. Unfortunately, this is not promising especially considering Doyle was coming off a contralateral ACL tear. Add in that he is a former fifth-round pick, the team doesn’t have as much invested in him as others on the roster. 

While the rehab timeline for the general population following an injury such as this is still about 9-to-12 months, it takes a little longer in elite athletes. On average, players who suffer a multi-ligament knee injury return in 459 days which is over 15 months, putting Week 1 in jeopardy. Furthermore, only 37 percent return to play the following immediate season. Finally, only 18.5 percent returned to their prior level of performance. 

Doyle will likely have two surgeries to repair the damage. They will likely repair the LCL first and any other associated damage in the posterolateral corner before going back several weeks later to repair the ACL. 

At this point, Tommy Doyle has to focus on the rehab at hand and work on getting one percent better every day. 

As awful as this information is, there are some promising comparables at different positions. This article from The Athletic does a fantastic job highlighting some of the players that have had a similar injury and their outcomes. This list is not exhaustive, but a handy reference point.

Denver Broncos RB Javonte Williams suffered his injury in early October 2022 and has since been activated from PUP, on track to play Week 1. 

Baltimore Ravens JK Dobbins suffered a similar injury in the 2022 preseason and was ready in Week 1, though his performance initially left something to be desired. 

Washington Redskins QB Robert Griffin III famously tore his during a playoff game his rookie year and never quite regained his form.

Looking at nerve damage, former Cowboys LB Jaylon Smith severely injured his knee, tearing his ACL and injuring his peroneal nerve in the bowl game his senior year while playing for Notre Dame. He slowly made his way back playing with an AFO to allow him to dorsiflexion his foot until the nerve healed.

There is the example of former Washington Commanders QB Alex Smith wearing an AFO when he returned to the field, but his case is like comparing a pebble to a boulder.

Re-injury Risks & Concerns

Doyle was already at higher risk to tear the contralateral side due to the right ACL reconstruction. However, while this was non-contact, this was still a freak accident and I do not believe that his prior ACL contributed to this injury. 

There are still risks associated when coming back such as re-injury rates. 12.3 percent of players reinjure their same knee versus the 7.3 that injure the opposite knee. These risks are unfortunately present for upwards of the next two years. 

The hope is that he has a mild nerve injury that will heal on its own in time. If everything is intact, then the nerve function returns in about 3-4 weeks. Even if there is more significant damage, complete nerve palsy still saw 38 percent of patients regain reasonable function of dorsiflexion. If there was partial nerve palsy, these rates shot all the way up to 83 percent. 

If Doyle can get the full function of his nerve back, then that will help immensely. Considering the resources he has at his disposal, there is a higher likelihood that this happens. Once the nerve function is back, then he can focus on the rehab once more, going in with some confidence and familiarity having just performed it all. 

Tommy Doyle can return to play in the 2024 season, it just remains to be seen when and how effective he can be as a player. He has the ability to beat the odds because he has an excellent training staff working with him and he’s been through the rehab before.

This is a highly unfortunate injury, especially after last season’s ACL tear. I wish him the best of luck in his recovery as he fights to return to the NFL.

Top Photo Credit: NBC Sports