Knee mechanics associated with patellofemoral cartilage changes after ACL reconstruction
Modifiable mechanical factors of the knee may be associated with patellofemoral cartilage changes and reduced knee function in sports and recreation 2 years after ACL reconstruction, according to published results.
Researchers compared MRI ultrashort echo time-enhanced T2* (UTE-T2*) relaxation times in patellar and trochlear deep cartilage with patient-reported outcomes and ambulatory gait metrics among 60 patients 2 years after ACL reconstruction. Patients who underwent ACL reconstruction had gait metrics compared with 60 uninjured reference patients matched by age, BMI and sex, and ACL reconstruction UTE-T2* values compared with 20 uninjured reference patients, according to researchers.
Results showed an association between higher trochlear UTE-T2* values and worse knee injury and KOOS sport/recreation subscale scores. Researchers also found a trend for association between higher trochlear UTE-T2* values with worse KOOS pain subscale scores. Researchers noted an association between greater external rotation of the tibia at heel strike with higher patellar UTE-T2* values 2 years after ACL reconstruction, as well as an association between greater knee flexion angle with higher trochlear UTE-T2* values. Greater knee flexion moment had a trend for association with higher trochlear UTE-T2* values 2 years after ACL reconstruction, according to results. Compared with reference knees, researchers found patients who underwent ACL reconstruction had elevated patellar cartilage UTE-T2* values, knee flexion angle at heel strike and external rotation of the tibia at heel strike.
“These findings support optimization of patellar tracking and restoration of knee extension as therapeutic targets,” the authors wrote. “Patellofemoral MRI UTE-T2* cartilage mapping shows utility as a potential outcome metric for future studies of surgical techniques and rehabilitation strategies to improve patellofemoral health and patient-reported outcomes after ACL injury and reconstruction.”