Is Running Safe After Meniscus Surgery?

For those who call themselves “runners” the thought of doing a different form of exercise after meniscus surgery sounds like an impossible request.  Truly, there seems to be a unique and special bond runners have with hitting the road, finding their stride, getting away from it all, and achieving the euphoria of the runner’s high.  To ask someone to give up their stress relief and passion is advice I am hesitant to give unless I have concrete facts to back up my claims.  Additionally, if runners out there are being truthful, they rarely listen to advice if it pertains to cessation of running for even 1 day, let alone the rest of their lives.  Therefore, the goal of this post is to bring awareness, not ultimatums, to runners about the current research following meniscus surgery, rehabilitation, and the biomechanics associated with return to running. 



Let us first discuss meniscus surgery.  Although compared to other knee operations meniscus surgery is less invasive, there remains some physiologic changes that need to be respected and monitored in the rehabilitation process.  The primary role of the meniscus is to act as a shock absorber during weight bearing activities assuming 70% of the load at the knee.  Along with shock attenuation, the meniscus assists with joint gliding, limiting hyperextension, and protection for the knee joint cartilage itself.  The meniscus has pain receptors which is why it hurts when there is a tear.



For this article we will discuss only meniscectomy surgery (taking out a portion of the meniscus) versus a meniscus repair (using sutures to fix the tear, mostly done in younger populations).  When a meniscectomy is performed, the partial meniscus tear is removed resulting in physiological and anatomical changes:

·       Decreased joint surface protection

·       Decreased shock attenuation

·       Decreased knee stability

These changes can result in degenerative changes at the knee due to decreased protection of the knee articular cartilage.  Multiple studies have noted an increased risk of developing osteoarthritis at the knee following meniscus surgery.  This does not mean that everyone that has a meniscus surgery will get arthritis; however, one should be aware of the anatomical changes taking place to better plan through recovery and beyond.  Directly following your surgery there will be localized swelling around the patella and lower quadriceps that will last anywhere from 1 week to 3 months.  This localized swelling is important to address since it impedes the development of your quadriceps.  It is essential to have a strong and full contraction of your quadriceps before resuming a walking (and for sure a running) program.  To ensure your quadriceps are firing correctly you should be able to:

1.     Straighten your leg fully

2.     Squeeze your thigh muscles so that the knee cap glides upward towards your hip

3.     Perform 10 straight leg raises while lying down with your leg fully locked straight

As a physical therapist I often see people progress too quickly through rehabilitation in the hopes of returning to running ASAP.  This may help your mental status knowing you are back sooner than expected; however, sooner does not necessarily mean you have achieved the best possible outcome.  Multiple studies have concluded that after meniscus surgery walking gait mechanics on the operated leg are altered and deficient for proper shock control.  This means there is decreased bend at the hip and knee or improper alignment (check out this article: Knee Joint Biomechanics following Arthroscopic Partial Meniscectomy) causing compensatory motions at the pelvis, trunk, and opposite leg to make up the difference.  

You may have friends that state they were back to running after knee surgery only to find that at the 2-3 month mark post-op they were reporting lower back pain or opposite knee pain.  This should raise a red flag that they likely shortened their recovery time and did not achieve peak condition before returning to running.

So how will you know that you are fully ready to return to running?  If you can achieve peak condition should you return to running?  I can hopefully shed some light on both these questions.
Our understanding of the biomechanics of running has broadened greatly over the last 15 years.  Due to the wealth and diversity of information on running mechanics there is now a difficulty finding accurate information.  The truth is that research has not decided on a “perfect” way to run.  Research is able to point out many ways on how not to run. 

Most clients will begin a return to running program around the 8-12 week mark after their meniscus surgery.  This provides a fair amount of time for swelling reduction, quadriceps and hip strength, and progression and training for normal walking mechanics.  There needs to be an evaluation performed of your biomechanical movement to determine if the body is ready to tolerate the increased loads of running. (2-3 times body weight).  Here are the absolute needs from a physical therapy and biomechanics point of view to start a return to running program.

1.   Full pain free range of motion at the knee

2.   Excellent quadriceps strength equal with the opposite leg

3.   No pain with walking, stairs, or squatting

4.   Ability to demonstrate proper knee and hip control with a double and single leg squat

5.   Ability to perform 10 single leg step downs from an 8 inch box with good alignment

6.   Ability to perform 25 single leg calf raises on one leg

7.   Ability to perform 50 double and single leg “mini hops” in place, forward, and backward without pain and good control

8.   Hip strength even with the opposite lower extremity



Proper biomechanical hip and knee motion with squatting

This is some serious criteria but we have to keep in mind the nature of running itself.  If we look at the biomechanics of running we realize that running is just a bounding single leg squat performed over and over again.  At no point during running are both feet on the ground.  That is the reason single leg squatting and step down tests are important to check since it has the most specificity of training to running.  Likewise, running is ballistic in nature and therefore “mini” jumping is needed to prepare the articular cartilage of the knee for increased impact forces.  If available, it is important to compare your loading rates using a force plate.  By jumping onto the force plate with each leg you can determine whether you are absorbing shock with your “active” system, the muscles, or the “passive” system the bony anatomy.  It takes many repetitions and time for your body to learn the motor control necessary to actively absorb shock.  Passive shock absorption leads to joint break down, arthritis, and potentially ligamentous injury.
Once you have passed the above testing you are ready to begin your return to running progression.  Just like large jumps in mileage during non-injured training will likely cause damage it is important not to progress back to pre-injury mileage too quickly.  Most studies suggest a run-walk program to gradually increase tissue loading in a predictable and progressive fashion. 

It is important that skill practice for running is integrated into the return to running progression.  This practice is for plyometric control of single leg activities involving hip and knee flexion.  Learning and practicing the control of loading rates and ground reaction forces will protect your knees for the long haul.

1.     Does running itself cause arthritic changes at the knee?

2.     What are the risk factors associated with arthritis progression and running after meniscectomy?

Does running itself cause arthritic changes at the knee?
One would assume that all the pounding and increased joint forces acting on the knee while running would increase the likelihood of developing arthritis.  This seems to make sense given that articular cartilage is affected by high loads and high frequency of loading.  When consulting the research; however, a different outcome is recognized.  Multiple studies have reported no significant correlation between the action of running and development of knee osteoarthritis.

The risk of osteoarthritis with running and aging: a 5-year longitudinal study. Lane NE, Michel B, Bjorkengren A, Oehlert J, Shi H, Bloch DA, Fries JF J Rheumatol. 1993 Mar; 20(3):461-8.

The relationship of running to osteoarthritis of the knee and hip and bone mineral density of the lumbar spine: a 9 year longitudinal study. Lane NE, Oehlert JW, Bloch DA, Fries JF J Rheumatol. 1998 Feb; 25(2):334-41.

 Long distance running and osteoarthrosis.  Konradsen L, Hansen EM, Søndergaard L
Am J Sports Med. 1990 Jul-Aug; 18(4):379-81.


This is a small sampling of the literature discussing running and osteoarthritis.  Newer research has come to the same conclusion that the nature of running itself is not a risk factor for the development of osteoarthritis.  In fact, some researchers have gone as far to say that running can even decrease the risk of pathology at the knee.  Even runner’s world has put out a group of articles trying to debunk the myth that running causes arthritis.  So running is not the culprit in creating OA at the knee than where does the blame sit? 
 
What are the risk factors associated with runners, meniscus tears, and those who develop arthritis at the knee?

Research has not settled on one particular factor but instead a list of factors that will increase the likelihood of arthritic development following meniscus surgery:

·       BMI over 30

·       Age over 40

·       Degenerative meniscus tear versus traumatic

·       Previous history of osteoarthritis, per X-ray, prior to the meniscus injury

·       Amount of meniscus removed > 1/3

·       Female gender

·       Lateral (outside) part of the knee affected

·       Knee turning out (varum) or turning in (valgus) with dynamic activities

The highest correlated factor for development of arthritis with running following meniscus surgery is presence of arthritis prior to the surgery.  To state it another way, if you have arthritis before surgery you will have it after and the surgery and therefore running is likely to progress the arthritis (regardless of how optimal your running form is).  From looking at the list one can glean that many of the risk factors are unchangeable such as amount of meniscus torn, gender, and trauma and side of the tear.  There are other factors that are in one’s control to improve upon such as BMI and lower extremity alignment.  By decreasing your overall weight and seeing a physical therapist who will help you correct your lower extremity control you will decrease the chances of developing knee arthritis with running.

Conclusion:
After consulting the research, and drawing on years of experience treating runners after surgery, it is safe to conclude that running in and of itself does not cause arthritis or increased knee damage.  We know that increased damage to the knee, after surgery, is likely if certain risk factors are present.  To review these include: BMI over 30, age over 40, arthritis prior to the surgery, lateral meniscus tear, female gender, degenerative tear of the meniscus, and more than 1/3 of the meniscus removed during surgery.  From a physical therapy and biomechanical perspective the risk factors include: decreased quadriceps, hip, and gluteal strength, poor pelvis and knee alignment with a single leg step down, squat, and plyometric jump, decreased knee/hip range of motion, and poor dynamic active shock absorption.  If you are a runner and have the majority the unchangeable risk factors after surgery it is recommended that you pick up another form of exercise such as cycling to protect your knees and limit your chances of developing arthritis.  If most of your risk factors are associated with biomechanical and strength limitations than it is recommended your complete a comprehensive return to running program.   

The goal of this post was to shed some light on meniscus surgery and running and I hope I provided the readers with some insight and a plan of action.  This was lengthy and dense but I felt it was important to get some concrete data on a very common situation.  Best wishes to all runners recovering from meniscus surgery.

Written By:  Kevin Vandi DPT, OCS, CSCS
Owner of Competitive EDGE Physical Therapy San Jose
Serving--San Jose, Campbell, Almaden, Los Gatos, Bay Area