Knee Injuries in Athletes: Diagnosis and Recovery
Published at 9 Oct 2019

In this article we take an in-depth look at the characteristics of iliotibial band syndrome, which leads to pain in the lateral region of the knee in runners and cyclists, and also outlines the risk factors for developing this injury.

 

 

Iliotibial band pain syndrome (ITBPS) is a condition characterised by sharp pain affecting the outside of the knee. Originally, researchers believed that this occurred due to friction’ at the point where the iliotibial band (ITB) attaches to the outer part of the knee. However, subsequent research suggests this is unlikely because of the anatomical thickness of the ITB tissue, which prevents any sliding movements of the tissue over the bony protrusion known as Gerdy’s tubercle(see figure 1 below). This compression causes local inflammation, which is thought to cause symptoms that are common in athletes, particularly runners and cyclists.

Figure 1: Anatomy of the iliotibial band (showing Gerdy’s tubercle)

Anatomy of the Iliotibial Band

The ITB is a thick longitudinal extension from the tensae fasciae latae (TFL) muscle on the outside of the hip, and has attachments to the gluteus maximus of the buttocks also. It has an average length of 88cm covering the full length of the thigh bone, and attaching onto the end of the thigh bone and beginning of the shin bone. It is a stiff structure and can only lengthen 0.2% when placed on full contraction by the TFL.

How common is ITBPS?

The incidence of ITBPS in runners is estimated to be between 5-14%, and it is the most common running injury to the outside part of the knee. It appears to be more common in men: in the ITBPS population, the prevalence of women is reported to be between 16-50%, and for men between 50-81%.

What does ITBPS feel like?

ITBPS is commonly described as an aching pain on the outside of the knee, which can be sharp at times and sometimes in a pin-point location. This pain is normally aggravated by running, particularly downhill. Runners usually report symptoms presenting at a consistent distance in the run each time. Commonly, alterations in distance, terrain, technique, or speed can all be triggers for ITBPS; the implication is that any changes to training routine should be introduced slowly – perhaps no more often than every two weeks.

Diagnosis

Diagnosis can be made following an assessment by a skilled clinician – for example, a physiotherapist – who will take into account your history and symptoms. Due to the clarity of the presentation of this condition, further investigations are usually unnecessary. However, magnetic resonance imaging (MRI) or ultrasound (US) scans can provide further confirmation (see figure 2).

Figure 2: MRI image of knee affected by ITBPS

MRI Scan of a Knee

Figure 2: Different angles of an MRI showing signs of changes to the ITB where it attaches to the knee (white arrow showing small area of increased whitening).

What is the purpose of the ITB?

The ITB is controlled by the TFL muscle. Along with the gluteus maximum, the TFL tightens the ITB, and (through it’s attachment to the outside part of the knee) helps the front thigh muscles (quadriceps) to create a straightening action of the knee. When in weight bearing, the TFL and ITB help to steady and control the movements of the pelvis and thigh bone on the shin bone, which of course is very important when considering the impact created when running (see figure 3 below).

Figure 3: action of ITB during running

ITB Running

Why are runners at risk?

A runner’s biomechanics can predispose them to ITBPS. Small changes in angles can be a catalyst, particularly when considering the repetition involved in running. It is very hard to monitor technique externally without using video technology. The following variables to reduce the risk of ITBPS should be monitored when running:

*Knee bending angle when landing

Runners have an average knee bend angle of 21˚ at foot strike. However, runners become at risk of ITBPS with a knee bend angle occurring at, or slightly less than, 30˚. As a result of this angle, the fatty tissue underneath Gerdy’s Tubercle is thought to be repeatedly compressed, therefore causing pain. In terms of running gait, this can be caused by over-striding or prolonging your contact time with the ground when landing.

*Foot cross-over landing

When running on a treadmill, imagine a line going down right down the middle. Cross over landing is when your left foot strikes across this line to the right side and vice-versa (see figure 4) . This landing pattern increases the inwards angle of the knee and hip when striking the floor and is therefore thought to contribute to ITBPS.

Figure 4: Crossover landing

Crossover

*Opposite hip drop when landing (Trendelenburg gait)

When landing whilst running, imagine a line reaching from one side of your pelvis to the other, much like a belt would. If the opposite hip drops to below this line, it is thought to encourage more strain to the outer hip tissues upon landing, which is thought to contribute to ITBPS at the knee. This can be referred to as a Trendelenburg gait (see figure 5).

Figure 5: Trendelenburg gait when running

Trendle

A (on left) shows a normal gait). B (on right) shows a Trendelenburg gait, leading to increased loading on the weight-bearing hip soft tissue.

Diagnosis and Recovery of ITBS and Lateral Knee Pain

In cases of chronic lateral knee pain, iliotibial band syndrome (ITBS) should be considered as a possible cause. An athlete with this complaint will experience sharp stinging pain on the outside of the knee, which may be sufficiently intense to cause a limp.

In weight training, lateral knee pain can be induced by squats, lunges, hamstring curls, extensions and any motion that involves repetitive flexion and extension of the knees. In runners it may occur as a result of running up and downhill and on banked surfaces. Whatever the trigger for the problem, correct diagnosis and treatment are vital to allowing a return to pain-free activity.

A number of factors can trigger ITBS, but poor training habits are the key culprits. Any sudden increase in training intensity – whether that increase comes from extra weight, an increase in reps, greater distance or training on uneven ground – can lead to lateral knee pain. The problem can also be caused or exacerbated by structural abnormalities within the body, including pelvic torsion or obliquity, sacroiliac joint abnormality, and foot pronation (foot turning inwards) with excessive internal tibial rotation (shinbone turning inwards).

In most cases, evaluation of the problem is straightforward. The athlete will complain of knee pain brought on by repetitive flexion and extension and may report a limp following exertion. Swelling is not usually evident and there is no history of acute trauma – an instant injury caused by falling over or hitting the knee on a hard surface. Full weight bearing on the affected leg with the knee in 30-40° flexion will reproduce the pain, as the ITB comes in contact with the lateral femoral condyle.

Athletes are normally advised to continue exercising, as long as they avoid activities which aggravate the pain – and that normally includes running. Lower body weight training can be performed – with certain modifications. But the aim of training during this acute injury phase is to minimise losses rather than to maintain peak strength levels. Never train through an injury in the hope that it will go away. It may do in some cases, but it will return to plague you in future – and with more serious consequences!

Squats can be performed in a range of motion that will avoid pain – ie from standing to a bent knee position of 30°. (ITBS pain usually occurs at 35° flexion.) Back squats, assisted by a partner, can be performed on a Smith machine, moving from a bent-knee position of 90° to a semi-erect position of 45-30° of knee flexion, which avoids the painful portion of the range of motion.

Leg presses can be done from a bent-leg position to a semi-extended position between 30 and 45° of knee flexion, while quad extensions can be done from 90° of knee flexion to an extended position of 45-30°. Hamstring exercises can be done from a straight-legged position to a bent-knee position of 30-45°. Calf exercises need no adjustment since they are done with straight legs for the gastrocnemius, or seated with knees bent at 90° for the soleus. Swimming is useful for maintaining cardiovascular fitness, as long as you concentrate on the front crawl rather than breaststroke.

After a period of 2-4 weeks, when acute pain has subsided and lateral knee pain can no longer be reproduced when bearing weight, athletes can return to using a more complete range of motion during lower body weight training. The body takes time to recover from an injury and there are no short cuts in this area.

To avoid lateral knee pain from ITBS, take a hard look at your current training routine and check that you are warming up and cooling down correctly, as well as stretching. The body is an amazing piece of evolutionary engineering but, while it is flexible, it will not tolerate abuse indefinitely. Always listen to your body and rest when appropriate, or shift the focus of your training to another part of your body. Finally, bear in mind that this information is not intended to replace the advice or attention of health care professionals. Always consult your doctor for diagnosis and treatment of injuries.

 

 

 

 

 

 

 
 
 
 
 



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