There is still lack of knowledge regarding the variability of
patellofemoral alignment in healthy, non-osteoarthritic knees,
without patellofemoral instability. Therefore, a systematic review
of the existing literature was performed to evaluate the variability
of patellofemoral alignment.
Patellofemoral alignment of the knee was defined by the following
parameters: sulcus angle (SA), femoral trochlear depth (FTD),
patellar tilt angle (PTA), lateral patellofemoral angle (LPFA),
lateral femoral trochlear inclination (LFTI) and tibial
tubercle-trochlear groove distance (TT-TG). The electronic databases
MEDLINE and EMBASE were searched from database inception to search
date (January 11, 2019) and screened for relevant studies. The
PRISMA guidelines were followed. Articles reporting PF alignment
measurements of healthy knees in patients between 15 years and
47 years were included.
A total of 15 studies met the inclusion criteria. The studies
reported mean values and standard deviations for the SA between
118.7° ± 7 and 168°; for the FTD
between 3.4 mm ± 1.1 and
7.1 mm ± 1.8; for the PTA between
0.7° ± 4.99 and
17.05° ± 4.3; for the LPFA between
6.26° ± 4.1 and
11.1° ± 4.0; for the LFTI between
16.3° ± 2.8 and
22.1° ± 1.9; and for the TT-TG between
9.8 mm ± 4.6 and
17.3 mm ± 5.3.
LEVEL OF EVIDENCE
Patellofemoral alignment in the healthy knee is extremely variable.
A more precise knowledge of the complex relationship between the
patella and the trochlea may help to better diagnose PF disorders
and eventually help in selecting the correct therapy. Furthermore,
standardised imaging protocols and measurement techniques for
patellofemoral parameters are needed.