achilles: connecting the calf and the foot

Monday, January 26, 2015

Injuries can be thought of like real estate .What is important is location, location, location. The location of Packer Aaron Rodgers’ calf muscle tear and Pistons Brandon Jennings’ Achilles tendon rupture are separated by only a few inches, but it’s the difference between being oceanfront and being inland, ski in/ski out or a shuttle ride away. For Rodgers it means the ability to play through pain and for Jennings it’s a trip to the OR.

The gastrocnemius and soleus muscles form the muscles in the calf. They are attached to the heel by the Achilles tendon, so that when the muscles contract, the foot and toes plantar flex or point down like a ballerina on point. That motion allows push off by the foot so that walking, running and jumping can occur. Injuries to the muscle tendon unit are called strains and are graded based on severity. Grade 1 strains mean that the fibers have been stretched but not torn. Partial tearing of a muscle or tendon equals a grade 2 strain and grade 3 means that the muscle or tendon is completely torn.

calf

When Green Bay’s Rodgers strained his calf, it made walking and running especially difficult. While he could shuffle his feet to hand the ball off or staying the pocket to pass, the limp was obvious when he attempted to run. There were two reasons for that gait issue. First, the injury weakened the muscle making it difficult to push off with the ball of the foot but second and perhaps more importantly, there is an issue with foot dorsiflexion, or the ability to flex the foot upward. This motion is necessary to get the toes out of the way as the leg swings forward, but it also stretches the calf muscles causing inflammation and pain in the damaged area. Every attempt to run stretches and perhaps causes micro tears in the muscle fibers. Play is possible but performance suffers.

Detroit’s Jennings wasn’t so lucky. He completely tore his Achilles tendon, a grade 3 strain and the connection between the calf muscle and the heel was broken. No matter how much the calf muscles would contract, the foot would not be able to be moved. An Achilles rupture can happen without warning and the player usually complains of an intense pain like being shot or kicked in the back of the calf. The inability to plantar flex means that each step of walking, each running stride or even lifting the toes to climb a single step becomes a major challenge.

The Achilles anatomy allows the body to generate amazing jumping force and is due to the coiling of the tendon as it emerges from the muscle fibers of the calf. It spirals between 30 and 150 degrees to store and release energy and provide more power than what the calf muscle could generate on its own. The bad news happens if the foot gets stuck in an awkward position when that power is released, the tendon cannot withstand its own energy and shreds. This is different than the mechanism of a muscle strain where a single forceful event could cause damage, but just as likely, overuse is a common precursor prior to the muscle tear. The Achilles tendon can become inflamed because of poor body mechanism, age and other underlying diseases, but there may be no warning sign before the acute injury.

The difference between the calf muscle and Achilles treatment is night and day. Most athletes choose to have their Achilles tendon rupture surgically repaired so that they can heal, rehab and get on with their career, with the least time lost as possible. There is good potential to return to the previous level of activity, but there might be some loss of range of motion, and the risk of rerupture after surgery is between 0 and 5%. There are nonsurgical alternatives with aggressive casting, depending upon how the torn tendon ends align, and the outcomes are just as positive but the rerupture rate can be as high as 40%.

Muscle tears usually avoid the operating room. Time and rest are the healer of all. The risk of continued play has to do with worsening the tear but also potentially sustaining another injury, because other nearby structures may not be able to protect themselves from outside forces. Most people understand the concept of hamstring injuries needing months to recover and the same time frame exists for calf injuries as well. On a cellular level, both injuries will heal in the same way. Collagen fibers will cross link at the injury site and begin the building blocks to form scar tissue that will need to be strong enough to withstand the forces of running and jumping.

The distance between the belly of the gastrocnemius muscle and the middle of the Achilles tendon is about 6 inches, give or take, depending upon height. For the Packer faithful, that half foot meant that their quarterback could play but perhaps not as effectively. For Pistons’ fans, that distance caused them to lose their star player for the rest of the season and likely a good part of the one to come. For Rodgers it means extra time in physical therapy, but for Jennings, it is a trip to the operating room before that therapy can begin. Just like real estate, it’s all about location.

 

Image attribution: Orthopedics New England

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