What is the normal TT-TG distance?

Several studies suggest that a normal TT-TG distance is 10 mm or less [5, 7, 8]. A TT-TG distance greater than 15 mm in patients with patellofemoral insta- bility may predict limited benefit from phys- ical therapy [7].

What is an abnormal TT-TG distance?

For years, a TT-TG of 15 mm was considered the threshold limit. Today, a TT-TG greater than 20 mm is considered pathological and therefore to warrant correction.

How do you measure pct TT?

The tibial tubercle-posterior cruciate ligament (TT-PCL) distance was defined as the mediolateral distance between the tibial tubercle midpoint and the medial border of the posterior cruciate ligament. The distance was measured parallel to the dorsal aspect of the proximal tibia (dorsal tibia condylar line).

What is tibial tubercle Trochlear groove distance?

Background. Tibial tubercle-trochlear groove (TT-TG) distance is a measurement generally made on CT scans that is commonly used to quantify the risk of patellofemoral instability (PFI); however, its interrater reliability and accuracy as an indicator of PFI in patients is poorly characterized.

How is TT-TG calculated?

Draw a line along the posterior femoral condyles, and then draw the following lines perpendicular to this line:

  1. bisecting the tibial tuberosity (TT)
  2. bisecting the trochlear groove sulcus (TG)
  3. measure the distance between TT and TG = TT-TG distance.

What is insall Salvati ratio?

Insall–Salvati (IS) ratio is used in measuring the patellar height to detect patellar height abnormalities such as patella alta and patella baja. It is the ratio of the length of the patellar tendon to the maximum length of patella.

What is a patella alta?

Patella alta is a positional fault defined most simply as the superior displacement of the patella within the trochlear groove of the femur. Patella alta has been shown to be associated with chondromalacia on the articular surface of the patella and pain.

Is knee a ratio?

A normal value of the patella is a ratio between 0,5 – 1,0 . When the ratio is higher than 1,0, there is patella alta. The Caton-Deschamps index is the most commonly used radiographic technique for evaluation of patellar height. This is measured on a lateral radiograph of the knee in 30° degrees of flexion.

How is insall-Salvati ratio calculated?

The Insall-Salvati ratio was calculated by dividing the length of the patella tendon (LT) by the length of the patella (LP) measured from the lateral radiograph.

Can patella alta be cured?

Treatment of patella alta If a patient has significant patella alta that is causing specific problems (instability and/or patellofemoral wear/pain) then this can be treated effectively by surgically shifting the patella downwards by however far is necessary to put it into the normal position.

Is patella alta a problem?

The problem with patella alta is that the knee cap is very mobile from side to side and is predisposed to dislocation during sporting activities.

Is patella a ratio?

What is electronic distance measuring device?

Electronic distance measuring instrument is a surveying instrument for measuring distance electronically between two points through electromagnetic waves.

How do you measure astronomical distances?

The most accurate way to measure the distances to close stars is to use basic geometry. Astronomers measure the position of a star in the sky at six-month intervals, when Earth is on opposite sides of the Sun. If the star is close, then it will appear to shift a bit compared to the background stars.

What is an electronic distance meter?

Electronic distance meters (EDMs) are instruments that compare the phase difference between transmitted and returned electro-magnetic waves, of known speed and frequency, or the round-trip travel time of a pulsed signal from which the distance is calculated.