Items tagged “knee”

361 results found
Article

Cyclops lesion (knee)

The cyclops lesion, also known as localised anterior arthrofibrosis, is a painful anterior knee mass that arises as a complication of anterior cruciate ligament (ACL) reconstruction, although has rarely been reported in patients with ACL injuries that have not been reconstructed.  Epidemiology ...
Article

Discoid meniscus

Discoid menisci are those that have a body that is too wide, usually affecting the lateral meniscus. They are incidentally found in 3-5% of knee MRI examinations. Epidemiology Discoid menisci condition is congenital, frequently bilateral (up to 50%) and has been reported in twins, although no ...
Article

Double PCL sign

The double PCL sign appears on sagittal MRI images of the knee when a bucket-handle meniscal tear (medial meniscus in 80% of cases) flips towards the centre of the joint so that it comes to lie anteroinferior to the posterior cruciate ligament (PCL) mimicking a second smaller PCL. A double PCL ...
Article

Extensor mechanism of the knee injuries

Extensor mechanism of the knee injuries include: quadriceps muscle tears quadriceps tendon rupture patella tendon rupture patella fracture patellar dislocation often with medial retinaculum tears patella sleeve fractures Chronic injuries: Osgood-Schlatter disease Sinding-Larsen-Johanss...
Article

Lipohaemarthrosis

Lipohaemarthrosis results from an intra-articular fracture with escape of fat and blood from the bone marrow into the joint, and is most frequently seen in the knee, associated with a tibial plateau fracture or distal femoral fracture; rarely a patellar fracture. They have also been described in...
Article

Insall-Salvati ratio

The Insall-Salvati ratio or index is the ratio of the patella tendon length (TL) to the length of the patella (PL).  Insall-Salvati ratio This can be measured on a lateral knee x-ray or sagittal MRI. Ideally, the knee is 30 degrees flexed.  Distance lines used to calculate Insall-Salvati rati...
Article

Meniscal flounce

Meniscal flounces refers to the "ruffled" appearance of the inner margin of the knee meniscus. They were initially thought to be only an arthroscopic finding, as a result of joint distension and anaesthetic muscle relaxants but are rarely seen on MRI.  Epidemiology Meniscal flounces are rare, ...
Article

O'Donoghue unhappy triad

O'Donoghue unhappy triad or terrible triad often occurs in contact sports, such as basketball, football, or rugby, when there is a lateral force applied to the knee while the foot is fixated on the ground. This produces the "pivot shift" mechanism. The O'Donoghue unhappy triad comprises three t...
Article

Osgood-Schlatter disease

Osgood-Schlatter disease (OSD) is a chronic fatigue injury due to repeated microtrauma at the patellar ligament insertion onto the tibial tuberosity, usually affecting boys between 10-15 years. Epidemiology Osgood-Schlatter disease is seen in active adolescents, especially those who jump and k...
Article

Osteochondritis dissecans of the knee

Osteochondritis dissecans (OCD) most commonly affects the knee. See osteochondritis dissecans article for a general discussion. Pathology Location The condition occurs bilaterally in 25% of cases, and has a characteristic distribution 2,4,6: medial condyle: ~78.5% (range 70-85%) "classic" l...
Article

Popliteal artery aneurysm

Popliteal artery aneurysms are the most common peripheral arterial aneurysm and the second most common aneurysm after abdominal aortic aneurysms. Epidemiology Overall, popliteal artery aneurysms are uncommon. They occur almost exclusively in males (up to 97%) for unknown reasons 8-9. There is ...
Article

Quadriceps tendon

The quadriceps tendon is a thick tendon extending to the patella made up of contributions from all four quadriceps muscles. It classically has a trilaminar appearance: superficial layer: rectus femoris middle layer: vastus medialis, vastus lateralis deep layer: vastus intermedius See also q...
Article

Rim sign of avascular necrosis

The rim sign of avascular necrosis (AVN) comprises a high T2 or intermediate T1 signal line sandwiched between two low signal lines, and represents fluid between the sclerotic borders of an osteochondral fragment, and implies instability (stage III). The rim sign should not be confused with the...
Article

Spontaneous osteonecrosis of the knee

Spontaneous osteonecrosis of the knee, also known as Ahlback disease, SONK or even SPONK, has similar appearances to osteochondritis dissecans of the knee but is found in an older age group. Epidemiology SONK is seen more frequently in women (M:F 1:3) and affects older patients, typically over...
Case

Avascular necrosis of the knee

 Diagnosis certain
A.Prof Frank Gaillard
Published 07 May 2008
83% complete
MRIAnnotated image
Case

Discoid meniscus (degenerate)

 Diagnosis certain
A.Prof Frank Gaillard
Published 07 May 2008
68% complete
MRI
Case

Degenerative subchondral bone cyst

 Diagnosis almost certain
A.Prof Frank Gaillard
Published 13 May 2008
64% complete
MRIX-ray
Case

Knee joint effusion

 Diagnosis certain
A.Prof Frank Gaillard
Published 15 May 2008
69% complete
X-ray
Case

Celery stalk sign in ACL mucoid degeneration

 Diagnosis almost certain
A.Prof Frank Gaillard
Published 27 May 2008
46% complete
MRIDiagram
Case

Anterior cruciate ligament ganglion cyst

 Diagnosis certain
A.Prof Frank Gaillard
Published 27 May 2008
77% complete
MRI

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