Knee Injuries

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Introduction

The knee is a pivotal hinged joint with the joint line existing between the femoral condyles and the tibial plateau. The medial and lateral menisci are located between these bony surfaces. The menisci (also knows as semi-lunar cartilages) serve as cushions and protect the articular surfaces of the femur and tibia. Anteriorly, the patella, a sesamoid bone embedded in the quadriceps tendon, articulates with the trochlear groove of the distal femur. Stability in the knee joint is provided primarily by the lateral and medial collateral ligaments as well as the anterior and posterior cruciate ligaments. The knee is particularly susceptible to injury from trauma, inflammation, infection and degenerative changes (Luke & Ma, 2010).

A review of the clinical manifestations, screening and diagnosis, and treatment of some of the more common injuries follows.

It should be note that a knee injury is considered emergent when there is an open fracture, or obvious signs of infection.

 

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The Case of Mary T.

Mary is a 25 year old female rugby player who has come to your office after sustaining a knee injury during a match three weeks previously. She describes the injury for you: "I was chasing the ball and my leg was planted, I went to change direction and I heard a loud pop and grinding sound and I went down. I was in a lot of pain at first but I was able to walk myself off the field. Over the next few hours I noticed that my knee swelled a lot and was extremely stiff and painful so I went to the emergency department where they took x-days and told me I was fine". The swelling in her knee has decreased and her range of motion has progressed however she has returned today because she feels that the joint is unstable. She hesitates when walking down stairs and has noticed that she has a general sensation of instability and sometimes her knee buckles while she is walking. . . .

 

 

History and Physical Exam

A thorough history and physical examination are necessary components for proper evaluation of knee pain. A history should include the patient's description of the type and location of pain and the mechanism of injury (contact or non-contact). A detailed history should include information about what makes the pain better or worse and the presence of pain during the night, swelling, whether there is catching or locking of their knee (true locking requires the knee to be locked for a period of time without the ability to fully extend).

A physical examination of the knee should include an evaluation of the following:

• assessment of gait
• overall alignment of the knee joint (varus, valgus, neutral alignment)
• range of motion
• presence of effusion
• quadriceps atrophy
• localized tenderness
• strength
• special tests where applicable

Assessment of the hip joint is also important as some patients experience referred pain in the knee. Findings specific to the conditions mentioned above will be discussed within each section.

 

 

Anterior Cruciate Ligament Tears

The anterior cruciate ligament (ACL) connects the posterior aspect of the lateral femoral condyle to the anterior aspect of the tibia (Luke & Ma, 2010) and is comprised of two main bundles - the anteromedial band and the posterolateral band. This ligament controls lateral translation and rotational stability of the tibia as it articulates with the femur. Tears of this ligament are classified as partial or complete.

 

In the US the incidence of ACL tears is 100,000-200,000 per year with approximately 100,000 ACL reconstructions per year. ACL tears are often associated with sports injuries (up to 70% are associated with athletics) and this form of injury is becoming more commonly sustained by females (incidence in female soccer and basketball players is 2 - 8 times the rate of their male counterparts). Individuals aged 15- 29 are at highest risk, however they can occur at any age. The mechanism is usually one involving an acute, non-contact deceleration, hyperextension, or rotational forces.

 

 

Posterior Cruciate Ligament Tears

 

 

 

Medial Collateral Ligament Tears

 

 

Lateral Collateral Ligament Tears

 

 

 

Meniscus Injury

 

 

 

Tibial Plateau Fractures

 

 

Patellar Fracture

 

 

 

Patellar Dislocation

 

 

 

Tibiofemoral dislocations

 

 

Resources and References

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