Pain on the outside or lateral aspect of the knee can often be a difficult one to solve for many people, and its not just seen in sports related injuries. In this blog we will take a look at a few of the potential sources of this tricky area.
The likely reason for this is that in a vey small area there are quite a few structures that can get injured through either a traumatic sports injury or repetitive overuse type injury. As such its a good idea to get this type of knee pain assessed to get back on the right path .
Proximal tibio fibular Joint related lateral knee pain
The Proximal Tibio Fibular Joint ,( PTFJ) as the name suggests is the joint between the fibula and tibia. It is an inherently stable ‘plane like’ joint on the posterolateral part the knee, and is stabilized the following structures:
- Biceps femoris tendon
- Lateral collateral ligament
- The primary capsule and ligament associated with the joint.
- Popliteus muscle and posterior ligaments of knee.
Most of the injuries to this joint will occur with the knee in a flexed position due to the stabilising role of the lateral collateral ligament.
Although rare it is possible to sublux or dislocate the PTF joint and commonly occurs in traumatic situation where the knee is flexed and the individuals ankle rolls underneath them. It is thought that a sudden protective muscular contraction then subluxes the fibula.
As such we need to be careful that we assess for ligamentous laxity at this joint in traumatic presentations of this injury.
Hamstring related lateral knee pain.
The Biceps femoris is the hamstring muscle that attaches to the fibular head. This is more often seen in individuals that participate in activities that involve sprinting..
Individuals often complain of an aching type pain at the back and outside of the knee on striding out when sprinting or running, fast walking and acceleration type activities. They may also report that the knee stiffens up with inactivity which is characteristic of tendinopathy type injuries.
Lateral meniscal tear and lateral knee pain
A lateral meniscus tear is an injury to the semi-circular cartilage on the outside of the knee joint. It can occur suddenly from pivoting injury on a fixed foot or it may develop gradually through general wear and tear.
It can be associated with localised lateral swelling and painful clicking and locking of the knee joint.
Ilio-tibial band and lateral knee pain.
the Ilio-tibial band’s (ITB) deep layer attaches to the lateral epicondyle with a fan of fibres called Kaplan fibres, and to the tibia at Gerdy’s tubercle. It has been proposed that “tight” ITB can create a friction based irritation at the lateral aspect of the knee creating lateral knee pain. You can read more about ITB related symptoms here
Popliteus tendon related lateral knee pain.
The popliteus is a muscle that starts within the knee, travels diagonally over the upper third of the lower leg and attaches to the tibia. Its role is to control the rotational stability of the knee and also provides a locking and unlocking mechanism when we want to bend the knee after being in extension.
It is not a common muscle to injury but can occur in pivot and twist type injuries. It can be misdiagnosed as an LCL or ACL tear, the major difference is there are NO instability symptoms in this type of injury.
Lateral knee pain and parameniscal cysts
This is relatively rare but cysts can develop at the lateral meniscus and will occupy space in the space between the lateral meniscus and fibular head. They appear to be associated with a history of meniscus tears and have been reported in 50‐100% of cases of meniscus tears .
If they are present they tend to cause pain towards almost full range of flexion and in some cases can irritate the common peroneal nerve.
Peroneal Nerve irritation and lateral knee pain.
The peroneal nerve is found at the head of the fibula and is in a vulnerable position to become irritated. This may be due to altered joint mobility or presence of parameniscal cysts, which we have just looked at.
Often the symptoms of this may spread further than the lateral knee and be in line with the innervation of the peroneal nerve. It may not be unusual to get associated pins and needles or numbness in this area.
This is not an exhaustive list , but as you can see there are many potential culprits in this region and it may be there is more than one involved. The key is if in doubt get it checked out and get assessed. Its likely that a solution can then be found to your problem.
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