What is increased TT-TG distance?
The mean TT-TG distance was 10.36 ± 0.5 mm for female subjects and 10.19 ± 0.5 mm for male patients. Increased TT-TG distance of > 20 mm is reportedly associated with pathologic patellar instability.
What is normal TT-TG distance?
The normal TTTG distance is 10 ± 1 mm with MRI being a reliable method of measurement. Literature supports a high degree of variability in reporting TTTG. This study establishes normal TTTG values, which will help in the assessment and treatment of patellofemoral disorders.
What is an abnormal TT-TG distance?
There is a degree of variability in the literature about what is considered an abnormally high TT-TG. TT-TG distance of more than 20 mm is believed to be nearly always associated with patellar instability .
What is TT-TG distance in the knee?
Sherbondy and Ashley Anderson, MD, Penn State sports medicine orthopaedics fellow, found average TT-TG distances of 12-13 mm in patients with repeated patellar dislocation (n=30), compared to 9-10 mm in normal controls without dislocation (n=38) (Figure).
What is TTT knee surgery?
A tibial tubercle or tuberosity transfer (TTT) is a surgical procedure to realign the tracking of the kneecap (patella). It involves removing a small piece of bone on the front of the shin bone and reattaching it with anchors or screws to a different position.
How is TT TG measured?
Draw a line along the posterior femoral condyles, and then draw the following lines perpendicular to this line:
- bisecting the tibial tuberosity (TT)
- bisecting the trochlear groove sulcus (TG)
- measure the distance between TT and TG = TT-TG distance.
How is TT distance measured in TG?
How long does TTT surgery take?
The incision required to perform the operation is approximately 3 inches in length and the entire surgery lasts about an hour.
Can you cure patella alta?
In severe cases of patella alta where the kneecap keep dislocating, or when conservative treatment fails, then surgery is necessary to effectively treat the condition.
How is CT TT TG distance measured?
Can a knee dislocation be seen on a xray?
In severe dislocations, the swelling may be so intense that the kneecap cannot be located without an X-Ray. An X-Ray can also be used to determine if there was any break or fracture sustained by the kneecap during the dislocation.
What is patellar translation?
Patellar translation is the distance between tibial tubercle and trochlear groove and is also called TT-TG distance. It is measured on CT or MRI by overlapping or superimposing axial images of the femoral condyles and tibial tuberosity. The measurements are used to quantify patellar instability.
What is TTO knee surgery?
Tibial Tubercle Osteotomy (TTO) is a surgical procedure to improve alignment of the patella. This is performed by changing the insertion point of the patellar tendon on the tibia (tibial tubercle).
Is surgery necessary for patella alta?
What is the normal TT-TG distance for a patella?
The TT-TG distance is normally about 9mm, and if it´s more than 15-20mm then it means that the alignment is poor, and there is increased stress upon the patella simply as a result of the person’s anatomy.
What is the effect of high TT-TG on patella?
High TT-TG would exert lateral pressure on the patella during extension, and if not counteracted by vastus medialis contraction, it may predispose to patellar subluxation Lateral patellar tilt Patellar tilt angle (Fig. 6) Patellofemoral angle Sensitive marker for patellar instability present in significant proportion of patients
What is the PTI of patella alta?
A newer method to assess for patella alta is the patellotrochlear index (PTI), which is measured in the midsagital MRI as the ratio of the length of trochlear cartilage engaged with the patella to the patellar cartilage length . PTI of less than 12.5% suggests the presence of patella alta.
Can imaging help in the evaluation of patellar maltracking?
The clinical evaluation of patellar maltracking is often challenging Imaging can detect subtle features that could lead to early diagnosis Imaging can detect predisposing factors for patellar maltracking and associated structural changes Management decisions are made on individual basis with imaging playing a vital role Background