The association of patellar tendinosis with patellar maltracking and Hoffa's fat pad impingement: A case-control MRI study.

OBJECTIVES: To assess whether proximal or distal patellar tendinosis is associated with patellar maltracking parameters and superolateral Hoffa's fat pad impingement.

METHODS: Institutional radiology database was reviewed for knee MRI scans performed over a 7-year period identifying cases of unequivocal patellar tendinosis, which were separated into 2 groups: proximal and distal tendinosis. For each group of proximal and distal patellar tendinosis, a control group of age and gender matched subjects was assigned. The scans were evaluated for patellar maltracking parameters including patellar alta, tibial tuberosity lateralization, trochlear dysplasia and lateral patellar tilt and for presence of superolateral Hoffa's fat pad edema. These parameters were compared between the case and control groups.

RESULTS: Out of 9852 MRI scans, 94 patellar tendinosis cases were included (65 proximal and 29 distal tendinosis) and matched with equal numbers of controls. In the proximal patellar tendinosis group, more subjects had patella alta (22 versus 6, p = 0.0006), lateralization of tibial tuberosity (16 versus 7, p = 0.0495) and superolateral Hoffa's fat pad edema (16 versus 4, p = 0.0073) compared to the control group. In the distal patellar tendinosis group, there was no significant difference in the prevalence of any maltracking indicator or superolateral Hoffa's fat pad edema compared to the control group.

CONCLUSION: Proximal patellar tendinosis was associated with patellar maltracking parameters including patella alta, lateralized tibial tuberosity and superolateral Hoffa's fat pad impingement. No association was demonstrated between distal patellar tendinosis and patellar maltracking indicators or superolateral Hoffa's fat pad impingement.