الفهرس | Only 14 pages are availabe for public view |
Abstract Historically, four principle anatomic factors have been identified that increase one’s risk of episodic patella dislocations. These are trochlear dysplasia, excessive patella height (patella alta), excessive lateral patellar tilt, and excessive tibial tubercle/trochlear groove (TT-TG) distance. A treatment algorithm has been proposed to correct these factors that includes bony realignment (Dejour et al., 1994). Trochlear anatomy is recognized as being important in patellofemoral stability. Trochlear anatomy includes not only the depth of the groove, but also its length. The patella achieves increasing stability in flexion due to not only the confines of the trochlear walls (depth of the groove), but also increasing tension in the retinacular structures. When the trochlear groove is short and shallow, the patella has greater excursion in early flexion unprotected by the trochlea. Likewise, patella position in the sagittal plane dictates the flexion arc at the time of patella engagement. The combination of an excessively high patella position combined with trochlear dysplasia offers increasing challenges for the kneecap to remain on a stable path to the protections of the trochlear groove in early flexion. The retinacular restraints have only recently been given importance as an anatomic factor critical for patellofemoral stability. The retinacular restraints protect the limits of patellar motion. The medial patellofemoral ligament (MPFL) has been recognized as the ‘‘essential’’ stabilizer against lateral patellar displacement (Amis, et al., 2003). |