Knee Problems Flashcards
Describe the key features of a proximal tibia fracture
Fractures of the tibia are relatively common, and occur most frequently in the middle aged and elderly. If the fibula is not fractured, it supports the tibia, and displacement of the fragments is minimal.
The proximal end of the tibia is the site that is most vulnerable to damage, resulting usually from some traumatic accident e.g vehicular. The condyles may be broken up in the fracture and it is not uncommon for there to be injury to the ligaments of the knee.
Describe the key features of a patellar dislocation
In a patellar dislocation, the patella bone is displaced out of the patellofemoral groove. It accounts for around 3% of knee injuries. Most dislocations occur laterally, and are caused by high force impact on the patella or forceful sudden twisting of the knee. These mechanisms of injury make patellar dislocation more common in individuals participating in sports such as: football, rugby and ice hockey.
What is a meniscal tear?
A meniscus tear is a common knee injury. The meniscus is a rubbery, C-shaped disc that cushions your knee. Each knee has two menisci (plural of meniscus)-one at the outer edge of the knee and one at the inner edge. The menisci keep your knee steady by balancing your weight across the knee.
Describe the key features of an anterior cruciate ligament injury
The anterior cruciate ligament (ACL) can be torn by hyperextension of the knee joint, or by the application of a large force to the back of the knee with the joint partly flexed. To test for this, you can perform an anterior drawer test, where you attempt the pull the tibia forwards, if it moves, the ligament has been torn.
Describe the key features of suprapatellar bursitis
Friction between the skin and the patella cause the prepatella bursa to become inflamed, producing a swelling on the anterior side of the knee. This is known as housemaid’s knee.
Describe the key features of superficial infrapatellar bursitis
Similarly, friction between the skin and tibia can cause the infrapatella bursa to become inflamed, resulting in what is known as clergyman’s knee (typically caused by clergymen kneeling on hard surfaces during prayer).
Describe the key features of a patellar fracture
Patellar fractures usually result from direct trauma to the bone, or sudden contraction of the quadriceps muscle. They are more common in males, and in the 20-50 age range. If the patella fractures into fragments, they will usually separate; the proximal fragment displaced superiorly by the quadriceps tendon and the distal fragment pulled inferiorly by the patellar ligament.
What is the ‘unhappy triad’?
Due to the attachment of the medial collateral ligament to the medial meniscus, damage to the medial collateral can affect this important cartilaginous structure. A lateral force to an extended knee, such as a rugby tackle, can rupture the medial collateral ligament, damaging the medial meniscus in the process. The ACL is also affected, which completes the ‘unhappy triad
What causes a meniscus tear?
A meniscus tear is usually caused by twisting or turning quickly, often with the foot planted while the knee is bent. Meniscus tears can occur when you lift something heavy or play sports. As you get older, your meniscus gets worn. This can make it tear more easily.
How do posterior cruciate ligaments occur?
The most common mechanism of posterior cruciate ligament (PCL) damage is the ‘dashboard injury’. This occurs when the knee is flexed, and a large force is applied to the shins, pushing the tibia posteriorly. This is often seen in car accidents, where the knee hits the dashboard. The posterior cruciate ligament can also be torn by hyperextension of the knee joint, or by damage to the upper part of the tibial tuberosity.
How do you test for posterior cruciate ligament damage
To test for PCL damage, perform the posterior draw test. This is where the clinician holds the knee in flexed position, and pushes the shin posteriorly. If there is movement, the ligament has been torn.
What is a Baker’s cyst and how does it present?
Popliteal cyst presents as a lump behind the knee
