Solving Anterior Knee Pain

Pain in the front of the knee is becoming an epidemic amongst serious weight lifters, athletes, and weekend warriors. It once was one of those injuries we associated mostly with females and blamed on their alignment, but no longer. I see almost as many men now with diagnoses like patellar maltracking, patellar tendonitis, IT band syndrome, and just general ‘anterior knee pain’.

There are multiple factors at play here that interact with one another to eventually cause pain and limit performance. Male or female, the causes can be traced back to poor joint mobility, tight and overactive muscle groups dominating stretched and weak muscles, synergistic dominance, and just plain sitting too much. In this article I will explore them all.

There are a number of common causes of anterior knee pain but some are more directly related to weight lifting and training for athletics.

 

1) Increased compression forces at the patello-femoral joint. Compressive forces are greatest at 90+ degrees of flexion especially open chain. This is one reason I recommend to my patients and athletes to stay off the leg extension machine. It is unbelievable how many people come in to rehab and specifically name that machine. Unless the patient is a body builder, they don’t need it. If they happen to be, then think about limiting the range of motion.

 

Performing squats with a wider than normal stance and high bar position has also been shown to increase compressive forces. The thought is that the trunk is in a more upright position which increases quad contribution (while decreasing the load on the glutes) and creates more compression. Many athletes and serious lifters will be hesitant to change their stance and bar position but enough pain may convince them. For those who use a Smith machine to squat (or leaning against a stability ball on the wall), I would reconsider just for that reason. Besides, nobody really moves or lifts like that in real life.

2) Increased stress on the patellar tendon as the knees go past the toes. There are times in life and in the weight room where the knee will make its way out past the toes, especially with squats and lunges. If the heels are down and hips are contributing properly then no problem. Once the heels come off the floor you can kiss any glute contribution good-bye. It’s all quad from there on out which means greater stress on the patellar tendon, shearing forces, and those nasty compressive forces again as well.

3) Increased knee valgus angle is another popular one. Once thought to be limited to females with wide hips, it’s surprising the number of men who now demonstrate this pattern. It may not show up until they squat heavy, or landing from a big jump, but that just tells me they’ve got strong quads and they’re lacking elsewhere. It’s fairly common to see numbers 2 and 3 together because once the heels come up the knees buckle in.

This valgus angulation at the knee is often what is behind the patellar maltracking issues. The patella is supposed to glide friction-free with knee extension – flexion. When the knees cave inward, the patella will track laterally and come into contact with the femur. The result is a roughing up of the cartilage under the patella which will become painful in time. This is a very common problem in the sedentary population when going up and down stairs, lifting, or trying to kneel down. For weight lifters, it’s squats and lunges.

So why do these things happen? All three of these issues (increased compressive forces with greater knee flexion angle, shearing forces as knees go over toes, and knees going into valgus) probably happen hundreds or thousands of times per day as we go through our normal daily activities. The key is limiting the amount of force and excessive movement in these directions during training and athletics. To do those things we must first look at what structures, when not functioning properly, can get us into trouble.

1) Soft tissue restrictions. The hip flexor muscles and TFL are frequently short and overactive. The problem is they are in opposition to the glutes which can then be inhibited (I’ll be ranting more about the importance of the glutes and knee control later).

Anterior/lateral knee pain can also be caused by trigger points in the glute medius and maximus pulling on the IT band. The IT band transmits forces from the glutes to the patellar tendon.

2) Restricted ankle dorsiflexion. This one is often over looked but it can cause an anterior weight shift during squatting and lunging activities resulting in the knees over the toes and valgus positions. To check ankle mobility, start in ½ kneeling position and the ankle in neutral. Bring the knee out over the foot as far as possible, use a stick to drop a line from the knee to the floor. The knee should be at least 4 inches past the foot without the heel coming up or the foot rolling in.

3) Poor glute function. The glute complex is responsible for hip extension, abduction, and external rotation. When functioning in the closed chain, as with squatting, they resist femoral adduction and internal rotation (knee valgus) and thus decrease stress at the knee (Ireland et al, 2003 and Bolgla et al. 2008).

4) Poor trunk control. Lack of control through the trunk will increase forces at the anterior knee during squatting, lunges, and deadlifts. Excessive lumbar lordosis (partially the result of weak glutes) will limit the ability to sit back into the squat thus creating an anterior weight shift and quad dominant movement. Not to mention increasing the possibility of back pain.

So how are we going to solve the problem of anterior knee pain?

1) Foam Roll the hip flexor group and TFL to inhibit tone and allow for a better stretch to these overactive muscles. Be sure to roll glute max and medius to reduce stress on the IT band.

2) Improve ankle dorsiflexion through mobilization and mobility work. My favorite technique is from Brian Mulligan using mobilization with movement to free up the ankle. To work mobility, the patient assumes the test position I discussed earlier, and places the stick just inside the knee but it should be touching the floor next to the 5th toe. Glide the knee forward keeping it outside the stick. This keeps the ankle supinated as it goes into dorsiflexion. Do not allow the heel to leave the floor.

3) Work hip extension. Poor glute function does not necessarily mean poor glute strength. It can be a matter of the lifter using a quad dominant strategy over a glute dominant strategy. In a quad dominant squat, the lifter begins the movement by flexing the knees vs the hips. It’s more of a straight down descent vs sitting back then down. This movement pattern automatically recruits more quad and leaves out the strong, powerful hip muscles. Not only will this increase knee stress, it also results in less than optimal squat numbers.

The ability to sit back first depends on the ability of glute max to eccentrically control the hip. If the patient can sit back simply by thinking about it, or by warming up with some light box squats, then it’s a patterning issue vs strength. If they cannot sit back effectively without feeling like they will fall over then it’s more of a strength issue.

Bridge variations are a great way to teach patients to recruit the glutes and build strength. The patient start with both heels pressing into the floor and lifts the hips until a straight line could be drawn from the shoulder through the hips and to the knees. The hamstrings should be doing very little to assist. If you can feel them tightening or the patients is cramping then they are substituting hamstrings for glutes. This is known as synergistic dominance but that is for another article. Just have them pre-contract the glutes before lifting and be sure to have them press through the heels. Progress to single leg bridging.

Don’t forget about deadlifts and/or single leg deadlifts. These are great exercises for overall hip development.

4) Activate/strengthen the outer hip. The glute complex and some of the smaller hip external rotator muscles play a crucial part in maintaining knee alignment. Knee valgus and patellar maltracking are not necessarily caused by a weak VMO as we once thought. It is actually the inability of these hip muscles to prevent adduction and internal rotation of the femur. The knees should be aligned with the mid to outer foot during squats and lunges for proper tracking of the patella.

The question comes up again: is it poor muscle activation/patterning? Or is it weakness? If I have an athlete that cannot break parallel with good form performing a body weight squat, then I will apply pressure to the outside of the knees pressing inward. The athlete is instructed to squat and press the knees out as hard as they can. Many times athletes will recruit the hip musculature enough that they drop right down into a full squat with perfect technique. If this is the case, they have the strength to do it but are not activating the hip muscles appropriately.

Overhead squat with valgus

Overhead squat using Reactive Neuromuscular Technique

Strengthening the hip abductors and external rotators can be done several ways but must be done correctly as trunk substitutions can take over the movement. The first two exercises would be used with someone who could not squat even with the activation technique described above. They can progress to exercises 3 and 4 once the first two are mastered. The athlete that can squat with the activation technique can start with 3 and 4 as part of their warm-up.

• Clamshells are a very basic exercise designed to target the external rotators of the hip in an isolated fashion. Be sure the patient keeps the trunk stable and resists rolling back as the knee comes up. Add band or tubing resistance around the knees to progress the exercise.
• Side lying hip abduction is another very basic exercise but requires strict technique. The top leg should be slightly extended at the hip and in a neutral to slightly externally rotated position. When lifting the leg you must be sure the hip is initiating the movement and not the trunk.
• Lateral band walks are done with a band or tubing around the knees for beginners and progressed to the ankles for a greater challenge. The athlete will abduct the lead leg then eccentrically control the back leg as it adducts back in (effectively working the abductors on both legs simultaneously). Watch for trunk compensation here as the QL can laterally flex the trunk to throw the hip into abduction. Perform one set right and left standing relatively straight and the second set in a quarter to half squat position.
  
• Squats with tubing around the knees uses a reactive neuromuscular training technique designed to activate the hip musculature and prevent valgus collapse at the knees. Much like the test I described above, use a good amount of resistance and instruct the patient to push the knees out while squatting down. Athletes can use this technique during their training warm-ups as well.

I cannot stress enough the importance of performing single leg squats. When on one leg, the hip muscles are working harder yet to maintain proper lower extremity alignment. Single leg squats will not only maximize protection at the knee joints, but are also great for speed and power. Don’t worry, I won’t get on my single leg training soapbox here.

5) Don’t forget to train for core stability. Core ‘stability’ exercises, like prone and side planks, bird dogs, and fire hydrants, work the trunk muscles by resisting excessive motion through the spine while simultaneously getting in some extra hip work. Core ‘strengthening’ on the other hand involves motion through the spine. Crunches, leg lifts, and back hypers would be examples of strengthening exercises. Squats, deadlifts, and lunges require a rigid, stable spine to protect the knees, put up big numbers, and for effective carry over to sports.

So there you have it. The common causes of anterior knee pain with lifting and training, and strategies to correct the weaknesses. Take a close look at what exercises or activities are causing pain and where the knees are aligned when it happens. Work these five corrective strategies into the patient’s workouts to keep the knees healthy and keep them playing.

1. 1. Ireland ML, Willson JD, Ballantyne BT, Davis IM. Hip Strength in Females With and Without Patellofemoral Pain. J Orthop Sports Phys Ther. 2003;33:671-676
2. 2. Bolgla LA, Malone TR, Umberger BR, Uhl TL. Hip Strength and Hip and Knee Kinematics During Stair Descent in Females With and Without Patellofemoral Pain Syndrome. J Orthop Sports Phys Ther. 2008;38:12-18.