Transcript of the Video I would like to show you a patient from some years ago who had patellar instability, evident by the 'J sign' which is descriptive of an abnormal movement of the patella during bending and straightening the leg. When the knee is bent or flexed, the patella engages properly in the groove of the underlying femur. But as the knee goes into terminal extension - …

The J-sign is when the kneecap 'pops out' (subluxes) to the outer side each time the knee moves into the fully straight position (terminal extension). Page updated March 2024 by Dr Sheila Strover (Clinical Editor)

Jul 13, 2005 · What does this mean "she has quite large J sign with active extension. The knee is clinically stable. Marked patellar subluxation laterally but joint space is fairly well maintained on standing 45', positive sage, chondramalacia patella with ticompartmental degenerative changes, most severe in patellofemoral joint. 6/2004 partial lateral meniscus removal and microfracture left knee 7/13/05 ...

Trochlear dysplasia is a condition of the knee where the trochlear groove is abnormal, usually at its upper end where it is abnormally flat or even heaped into a 'bump'. Page updated May 2024 by Dr Sheila Strover (Clinical Editor)

These include - trochlear dysplasia patella alta increased tibial external torsion valgus deformity medialised trochlear groove lateralised tibial tubercle combination of the above Back to top Positive J-sign Dr Lars Blønd explains how the surgeon can confirm patellar subluxation in the examination room by eliciting the J-sign.

Patellar malalignment may be due to an imbalance in the soft tissues during motion, or there may be underlying bony structural problems causing the patella to tilt or track abnormally. The problem may cause pain, subluxation or dislocation.

The authors also recommend to include in the examination an evaluation of the J-sign and the patellar apprehension test.

J-sign search for term The J-sign is when the kneecap 'pops out' (subluxes) to the outer side each time the knee moves into the fully straight position (terminal extension). Page updated March 2024 by Dr Sheila Strover (Clinical Editor) Joint search for term A joint is a junction between two bones. Joint cartilage search for term Joint cartilage is …

There may also be a ' J-sign ' where the abnormal excursion of the patella is visible when the patient ho lds the limb over the edge of the examination couch and flexes and contacts the knee.

Illustration of a high-riding patella (patella alta) subluxing to the outer (lateral) side during knee extension. Because the underlying trochlear groove is flatter at its upper end, it is easier for the patella to slide over the edge of the groove when the knee is in extension (straight).