Will I Hurt My Knee? 3 Easy Tests to Determine if You are Susceptible to Knee Injury

Read More About the Author Here: Samantha Pittsford, PT, DPT, OCS

That question is a common fear I hear from clients in the clinic.  Of all the joints in the body, it seems like the knee could be pretty easy to accumulate trauma or succumb to a traumatic injury. And of all the simple and common injuries that active individuals obtain, a knee injury seems to have the most long-term impact on a person’s physical capabilities.

While the previously stated comments are not necessarily true in comparison to other injuries, the bottom line is that knee injuries are very common. Of the top twenty diagnoses we saw in the physical therapy department last year, twelve of the twenty were related to the knee, while four were related to the shoulder, two for the hip, and two for the spine. In fact, the top two issues we treated were right and left knee pain, at a total of 1,044 cases. Number three and four on that list were right and left shoulder pain, with only a total of 468 cases. So at least for our patient population, a knee injury is very common, so it is understandable that people might have a fear of being susceptible.

As a Physical Therapist, I feel my role during a client’s recovery is to educate them on why knee injuries occur and how to control those factors, with the goal of preventing injury. While there seem to be so many things that could go wrong in this joint, (meniscus tear, patellar subluxation, chondromalacia, tendinosis and tendon ruptures, ligament sprains, and the big daddy of them all, the ACL tear, ) they ultimately stem from the same faulty mechanical issues, with exception of traumatic injuries like falls and car accidents. In fact, the most successful methods of intervention that have shown to decrease risk of knee injury in athletes, are interventions which focus on improving those mechanical errors.

The following are 3 simple tests you can perform on yourself, your clients, or your student athletes that will help determine if they have the mechanical deficiencies that increase susceptibility to knee injury.

1) Lateral Heel Tap

This is a great test that allows you to assess the strength and stability of the lateral hip and medial longitudinal arch of the foot during single leg loading, like with running and landing. The pelvis should remain parallel to the floor without drop on one side and the foot should stay neutral. As a result, the femur will remain relatively perpendicular to the floor, keeping the knee in a neutral alignment and promoting proper knee mechanics.

If the participant demonstrates a drop in the pelvis (left side dropping below line and right lateral hip popping out to the right of the line), or a foot that collapses through the arch, you will most likely also see medial rotation of the femur. This creates a valgus motion at the knee and makes the knee susceptible to injury.

2) Lateral Plank with Leg Lift

As long as there is no injury to the shoulder, this is an excellent test to assess lateral hip strength. As the top leg lifts up, the lateral hip muscles, mainly the gluteus medius, have to have proper strength to keep the pelvis from dropping to the floor. The gluteus medius plays an integral role in pelvic stability and maintaining optimal femur positioning during weight bearing activities like squatting and lunging.  This demand is even greater with single leg landing, such as with running and jumping.

This is also an excellent exercise to use as a benchmark for adequate lateral hip strength and promote knee health for athletes of all levels. You will want to be able to lift the leg up 10 times in a row without the hip dropping to the floor in order to demonstrate the proper level of lateral hip strength for knee protection.

3) Single Leg Landing

Lastly, single leg landing from a box is the best way to get an idea of lower limb stability and injury susceptibility for an athlete. Just like the first test, at the moment of landing, the pelvis should remain level and the femur perpendicular to the floor. If the femur rotates medially causing a valgus motion at the knee, this person is at high risk of knee injury with any impact activity, such as running, jumping, pivoting, or acceleration/deceleration.

Okay, let’s say you have now performed these tests yourself, or implemented them on a client or group of athletes, and you found not so promising results. Now what do you do and how do you fix it? The greatest aspect of these tests is they double as preventative exercises. When performed slowly and purposefully to limit the amount of hip drop and knee valgus that occurs, they become excellent functional strengthening  methods that promote good knee mechanics and decrease risk for injury. If you are currently having knee pain, these exercises might not be the best first intervention. Start with a check up with your orthopedist and/or physical therapist, but eventually passing these tests will be a good long term goal to achieve before returning back to your activity.

While knee injuries are common in the active patient population, they do not have to be disabling, and it is possible to keep them from happening in the first place.  The truth is many knee injuries are preventable if the proper supplemental strengthening and mobility exercises are performed in conjunction with a person’s favorite activity or sport. These three tests should serve as a good place to start.