Anterior Knee Pain and Runners

Anterior Knee Pain

Anterior knee pain is a common occurrence in distance runners. The knee is under influence from the foot below and the lumbo-pelvic girdle above. These influences dictate the range, load and pathomechanics placed on the knee.

The most common types of anterior knee pain in runners are;

• ·      Patello-femoral pain (PFPS)
• ·      Patella tendinopathy
• ·      Fat Pad impingement

Patello-femoral Pain

Patello-femoral pain is more of a syndrome – a cluster of symptoms rather than a well defined pathology. It is characterised by non-specific pain anteriorly, medially and often superiorly above the actual joint. There is sometimes a small amount of fluid present in the superior pouch above the knee known as an effusion. It is often aggravated by increased load to the patella-femoral joint such as stairs, squats, lunges and downhill running particularly where the joint is required to stabilise against eccentric actions.

Commonly, swelling and effusion cause the VMO to decrease activity, which further destabilizes the joint. The joint cavity becomes inflamed causing a synovitis. This is acts as a chemical irritant to local nociceptors

Patella Tendinopathy

This is often more involved in sports where jumping is common however, it also occurs in distance runners. The onset is gradual, similar to most tendinopathies warming up with activity only to progressively get worse as the tendon struggles to adapt.  Pain is usually located at the inferior pole  (bottom of the patella). In these cases the tendon may be thickened especially in long standing tendinopathies. Without appropriate management the prognosis is usually longstanding with a poor outcome.

A common factor involved in tendinopathies is the inability to bare the load through the myofascial system due to fatigue or poor firing patterns. This is evident in longstanding tendinopathies where the quad decreases in size and often strength. This gives way to poor load transference from the muscle to the tendon. Instead the tendon takes the load. Over time, this changes the microstructure of the tendon causing weakness and pain.

Fat Pad Impingement

The fat pad is a cushioned portion of padding sitting below the patella and behind the tendon. This is thought to absorb load and reduce the friction between the tendon and underlying surface. This is susceptible to impingement as the knee goes into extension particularly at end range. Hyperextension is the typical cause of injury with tenderness on palpation and a puffy appearance. The pain is quite localised and assessment is made by taking the knee into slight hyperextemsion with over pressure, and palpation directly to the fat pads. Palpation reveals exquisite tenderness and may co-exist with PFPS.

Runners who overstride will have an increased risk due to increased knee flexion/extension angles. Generally females have an increased size of their fat pads and may be at increased risk of impingement. Further, individuals with a patella that sit with the inferior pole tilted towards the fat pad increase compressive forces through this structure.

Possible Causes

• ·      Increase in hill work (particularly downhill)
• ·      Increase in volume
• ·      Poor recovery between bouts
• ·      Poor lumbo pelvic control
• ·      Biomechanics – overstriding due to posterior pelvic tilt or anterior pelvic shift – the classic ‘swayback’
• ·      Increased Q angle
• ·      Anatomical considerations ie; shallow femoral groove
• ·      Increased pronation
• ·      Overactive ‘tight’ hamstrings
• ·      Poor lateral/medial stability of patella

Fig 1. Anatomy of the patellofemoral joint, including the tibiofemoral joint. Structures inside the joint that may be the source of pain are not depicted.

Treatment

Treatment involves modifying or identifying the causative factor. Addressing the symptoms only by focusing on the knee will not provide positive long term outcomes. As previously stated the knee is heavily influence by the hip above and the foot below thus these factors need strong consideration. This could not be overstated in a closed chain exercise such as running.

Modifying hill work and volume is seemingly easy, though hard to do when there is no objective view. Make sure you receive professional advice when modifying load, volume and intensity. Addressing these factors will affect recovery in a big way!

Perhaps the biggest factor for runners is lumbopelvic control and biomechanics relating to overstriding. Weakness and poor timing of the hip abductors has been shown to influence normal functioning of the knee. That is, poor strength will cause valgus or varus positions of the femur dragging the patella with it causing an alignment issue. Alignment issues will irritate the underlying patella surface and over time may cause degenerative changes to the boney architecture.

 In terms of acute treatment the first step is minimising the swelling and inflammation. The standard protocol to reduce this with rest (load modification), ice and compression will help as will washing soda for acute subcutaneous effusion. Washing soda is quite alkaline drawing the fluid across the skin. When applied for a few hours or overnight – good results are usually seen. Care must be taken when left on for long periods as it may irritate the skin.

Increased Q angle is an anatomical design that affects women more than men. As females usually have wider hips the angle between the femur and the patella is increased. This factor changes biomechanics such that there is an increase in peak hip adduction, hip abduction and varus forces on the knee.

Other anatomical factors such as a shallow femoral groove or ‘tilted’ patella are best recognised and managed. Keeping load at a manageable level is the best option.

Overstriding is best addressed with feedback from an outside source (this will give objectivity). There are too many sources of feedback and proprioception going on to assess yourself. Changing stride length and pattern needs to be driven from the control of lumbo-pelvic area in conjunction with consideration to foot positioning – not just where it lands but how it lands.

Overactivity (usually ‘tight’ hamstrings) affects the knee by decreasing quad function exposing the joint and tendon to greater loading. Altering biomechanics will go a way towards addressing this. Further treatment can be achieved by soft tissue treatment to the affected area(s), hamstrings, TFL, psoas, glute min and med. Treating the inhibitory factors ie; the structures that decrease ability of those soft tissue that we want to assume the work load.

Strengthening the local area around the knee can be effective if it is part of an overall plan. Simply strengthening the VMO with end range leg extensions will not necessarily translate to increased stability during the gait cycle.

Further treatment options such as awareness taping and rigid style knee brace taping can be quite effective in poor patella-femoral alignment. Kinesio taping is receiving a lot of publicity and is in its infancy in the public eye (although, it has been around since the 80’s in terms of rehab).

Summary of treatment options:

• ·      Load modification
• ·      Biomechanics
• ·      Lumbopelvic stability and control
• ·      Soft tissue therapy
• ·      Joint mobilisation (in the case of stiff joint segments)
• ·      Awareness taping (short term)
• ·      Kinesio taping (proprioception and increased firing of muscles)
• ·      Stretching to areas of increased tone and tightness
• ·      Addressing foot position and function

The knee is subject to large forces. Knee pain is one of the most common reasons  distance runners attend a health care clinic. Keeping the lumbopelvic area and foot position controlled will help decrease injury risk factors to the knee.

Email: jimmybarker9@gmail.com

Overstriding in runners

Some quick thoughts today on overstriding in running. Overstriding in running is common, even in the more elite runners. It’s a hot topic at the moment with the advent of minimalist running shoes and the barefoot community pushing their side. Striking mid foot and fore foot has become the new ‘trend’.

So, how do we define an overstride? Overstriding is basically where you land outside your centre of mass, ahead of your body if you like. There are a couple of things that are usually apparent with overstriding;

1.    Posterior pelvic tilt

2.    Heavy heel strike (as opposed to a light or glancing heel-strike)

3.    Greater knee extension (meaning more work from the quads)

4.    Larger braking forces (deceleration)

5.    Considerably more work from the calves to ‘propel’ the runner

6.    More time on the ground (slowest portion of the gait cycle)

7.    Slower cadence

With all of this going on it looks to increase your injury risk profile. It is definitely less efficient and slower in nature. The key point is how do we recognise this and how do we change this. Does it really matter whether we mid foot or fore foot strike? Let’s look closer at each point.

Posterior pelvic tilt is one of the most common things occurring in distance runners with greater prevalence in the more mature athlete. As soon as this happens your sacrum is thrust into a position known as ‘counter-nutation’ effectively limiting your ability to extend your hips. This position shuts down the powerful glute and hamstring muscles from their ideal firing position. The propulsion is therefore gained from quads and calves.

Posterior pelvic positions leave the lumbar spine vulnerable to loading forces – especially the sacro-iliac joint and discs. The first thing you need to do is get your pelvis in a neutral to (slight) anterior tilt, without this it’s very hard for the lower limb and foot to be in a biomechanically correct position!

Heel striking is not inherently bad, it is more how you do it rather than if you do it. As you fatigue, heel striking becomes the preferred position. Even the great Haile Gebrasalasie ran in a glancing heel strike position towards the end of the marathon. The key point here is to try and keep your cadence a little shorter, allowing your foot strike to land closer to your centre of mass. This results in a quicker and lighter foot strike with lower braking forces and usually a strike that is more toward a mid-foot strike.

Greater knee extension occurs in relation to the posteriorly rotated pelvic position. Lack of glute and hamstring firing necessitates increased extension at the knee joint to lengthen the stride, simultaneously increasing lower extremity loading as the heel strikes the ground in a straightened (knee extended) position. To change this, you need to address the pelvic position.

Deceleration (braking) forces occur during heel strike outside the centre of mass with the foot in a strong dorsiflexed position. This creates a collision impact with opposing forces as opposed to the foot contacting the ground in a rotary motion. This rotary motion uses the ground to propel and push off allowing acceleration to continue through the full gait cycle. This allows the use of the elastic energy stored in the myotendinous unit through the stretch-shortening cycle.

With deceleration occurring the calves are forced to accelerate through mid-stance to toe off over a longer period of time, hence there will be larger forces acting on the lower limb. Due to the longer contact times the runner will be slower through their stride (the slowest portion is the time on the ground, more time on the ground equals slower stride).

Mid foot and fore foot striking is the new ‘trend’. A foot strike of this kind is not necessarily better. What is important is whether or not an overstride is present. It is not impossible to have an overstride with a forefoot strike especially if the runner forces the forefoot into plantar flexion in the belief that a forefoot strike is better! Deal with the overstride and let the foot land however it is used too.

With all this occurring it may appear as a long and lengthy period to correct.

As the body works as a kinetic chain one change can often alleviate others. Starting with the pelvic position is an obvious choice. This often helps with a foot strike closer to the centre of mass. Changing the cadence by as little as 5-10% may also assist by shortening the stride. These two changes often increase knee flexion angle on foot strike and increase hip extension.

Overstriding is a common problem that can be addressed in a step by step fashion. The most important factor is whether you end up striking close to your centre of mass, not whether you heel strike or not.

Pelvic Influences on Running Gait

Knee Pain in Runners

Overview and Clinical Observation of Knee Pain in Runners

The knee joint has a high rate of injury in runners and is subject to large forces during the gait cycle. The vast majority of knee injuries related to running are overuse in nature. The focus of this post will be an overview of running related knee injuries with further posts looking at specifics, healing times and treatment options.

The knee is a hinge joint with an arrangement of ligaments, bursa, cartilage and connective tissue in abundance. It is a simple design with fairly simple mechanics yet can become quite troublesome in chronic issues.

Fig 1. Surface anatomy of the knee. Dysfunction above and below the knee will increase loading through the joint.

Pain may present as anterior, anteriomedial, medial, lateral or posteriorly. The site of injury will dictate what type of tissue involvement there is, unless of course, referred pain is present (radicular or other).

From a broad perspective the big considerations on knee loading are the effect from the SIJ/hip above (lumbo-pelvic mechanics) and the functioning of the foot below. Poor mechanics of the lumbo-pelvic region considerably load the tissues of the knee in an uneven fashion typically resulting in pain and/or dysfunction. The glutes (medius and minimus), adductors and the VMO (medial portion of the lower quads) should function synergistically to provide optimal stability and transfer the load from the foot to the SIJ. This allows the knee to be in the best position mechanically.

Pelvic position will ultimately affect the loading of the lower limb and in particular the knee. As previously discussed in the biomechanics of running posture a pelvis rotated posteriorly will ultimately end in an overstride pattern typically landing in a heel first and knee locked position. This loads the joint and does not take advantage of the hamstring during mid-stance and hip extension.

Inability of the glutes to fire in time (late) or not at all will give rise to internal hip rotation, internal knee rotation and internal foot rotation as a consequence. In this case the knee injury is a consequence of poor lumbo-pelvic control. Treatment directed at the knee only will be a less than adequate result and certainly not optimal.

The mechanics of the foot itself may be a causative factor. As the foot makes contact with the ground, pronation typically occurs. Pronation attenuates the forces through the foot, allowing load to be spread across the foot. Pronation is desirable – it’s just how much and at what rate (as discussed in previous posts).  Excessive pronation may be due to a variety of factors, it is paramount to assess why this is occurring.

Further up the chain the thoracic may also be a factor to consider. The thoracic is largely influenced by arm swing, in particular, the amount and site of rotation that takes place. This has been discussed in a previous post and considers the effect of rotation on the lumbo-pelvic region and it’s flow on effect to the knee and foot.

Knee pain must take into consideration the biomechanics of the individual’s running posture and the causative factor. Treatment should be directed at alleviating these.

Further posts will look at different knee injuries common in the distance runner.