The Evaluation of Patellar Height: A Simple Method

Abstract

The plateau-patella angle, a new method of evaluating patellar height, can be measured rapidly with use of either a goniometer or digital software. Its range is easy to remember, it is reliably reproduced, and it correlates well with traditional methods. It is thus a valid and easy alternative method for the evaluation of patellar height.

The reliability of four widely used patellar height ratios

“…Patellar height can be assessed on radiographs using numerous methods and corresponding ratios [5][6][7][8], however none is perceived as the gold standard [5]. These methods either relate the position of the patella to the femur (direct assessment) or relate the position of the patella to the tibia (indirect assessment).…”

Patellar instability

“…Advantages of the plateau-patella angle include assessment using only a goniometer and that no calculations are required. In the study describing it, the plateau-patella angle was found to have high inter-observer reliability and compared favourably with the Insall-Salvati, Blackburne-Peel, and Caton-Deschamps indices 29 . The Merchant view is performed with the knee flexed to 45° over the end of a table with the legs supported 30 .…”

“…The plateau-patella angle is formed between a line tangential to the subchondral bone of the medial tibial plateau (the same line used for the Blackburne-Peel measurement) and a second line drawn from the posterior extent of the plateau to the inferior articular border of the patella 29 . The mean angle is 25° and patella alta is greater than 30°2 .…”

The influence of patella height on soft tissue balance in cruciate-retaining and posterior-stabilised total knee arthroplasty

“…Each patient had varus deformity, with those receiving CR TKA having a mean preoperative femoro-tibial angle in standing position of 185.0±7.3°and those with PS TKA, 186.6±9.6°. Pre-operative Insall-Salvati index (ISI) [14,15] was measured using lateral radiographs.…”