Effects of Time to Start Training After Acute Patellar Tendon Enthesis Injuries on Healing of the Injury in a Rabbit Model

Background:A patellar tendon injury is a common injury in sports. The optimal time to start training after an acute, proximal patellar enthesis injury is still unclear.Hypothesis:The time to start training after an acute, proximal patellar enthesis injury significantly affects healing of the patellar tendon 4 weeks after the injury.Study Design:Controlled laboratory study.Methods:The left hindlimbs of 35 mature female rabbits were randomly assigned to 5 injury groups including a 4-week natural healing group (NH4W) and 4 training groups that started low-intensity training at 24 hours (POST24), 48 hours (POST48), 72 hours (POST72), and 96 hours (POST96) after an acute patellar tendon injury, with 7 limbs in each group. The right hindlimbs of the NH4W group were used as a control group (CON). An acute, proximal patellar enthesis injury was created in all injury groups. The training groups underwent low-intensity quadriceps training for 2 hours per day and 3 days per week for 4 weeks. Histological and radiogr...