Abstract
This study was aimed to investigate the role of anatomic variations in patellofemoral
alignment in patients with or without Osgood-Schlatter disease (OSD) and to determine
the potential anatomic risk factors that may play role in the etiology. This prospective
observational case-control study was conducted on two groups of adolescent patients.
Group 1 comprised patients who were diagnosed as having OSD and group 2 consisted
of an equal number of age-matched patients who presented to the outpatient clinic
with traumatic knee injury and underwent knee radiographic examination but without
a diagnosis of OSD. Age, height, weight, body mass index (BMI), dominant side, and
level of sporting activity were recorded. Quadriceps (Q) angles were measured using
a long-arm goniometer with patients lying in the supine position with their knees
in full extension and contracting the Q muscles. On anteroposterior, lateral knee,
and tangential patella (Merchant and Laurin views) radiographs, the following measurements
were performed: Insall–Salvati (IS), Caton–Deschamps (CD), and Blackburne–Peel (BP)
indexes, congruence angles, lateral patellofemoral angles, sulcus angles, and patella
type according to Grelsamer's morphology classification. Both groups were similar
in respect of age (p = 0.160), sex (p = 0.311), height (p = 0.326), weight (p = 0.596), BMI (p = 0.153), and dominancy (p = 0.500). The rate of patients engaged in sports activities was significantly greater
in the OSD group (p = 0.003). No significant difference was determined between the groups in respect
to IS index, CD index, BP index, sulcus angle, lateral patellofemoral angle, and congruence
angle (p–values: 0.358, 0.995, 0.912, 0.802, 1.000, and 0.907, respectively). The mean Q angle
was measured as 15.6 ± 2.2 degrees in the OSD group and 14.3 ± 2.5 degrees in the
control group (p = 0.014). Despite the difference being statistically significant, it was clinically
insignificant because the difference was only 1.3 degrees. The principle etiologic
factor seems to be increased physical activity rather than subtle variations is patellofemoral
anatomy and alignment of extensor mechanism.
Keywords
Osgood-Schlatter - patellofemoral alignment - etiology - patella alta - patella baja
