Isokinetic strength profile of subjects with proximal patellar tendinopathy

Background. Proximal patellar tendinopathy is relatively common among sportsmen. However, the strength profile of subjects with proximal patellar tendinopathies is poorly described. Purpose. We aimed to determine the isokinetic strength profile in order to estimate the difference of muscular performance between the healthy and pathological limbs of subjects suffering of this chronic pathology. Study design. Cohort study. Methods. 43 subjects with chronic proximal patellar tendinopathy were involved. It has been based on the evaluation of the quadriceps and the hamstrings muscular performance of the healthy and pathological member on isokinetic dynamometer at the speed of 60°/s (C60) and of 240°/s (C240) in concentric mode and at the speed of 30°/s (E30) in eccentric mode. A visual analogic scale of pain (VAS) has been also realized after each isokinetic test. Results. The results of the isokinetic tests comparing the healthy to the pathological limb are meaningful for the different conditions of contraction and test speeds, just like the results of the VAS associated to those tests (p<0,01). Indeed, pathological knees had a maximum peak torque for the quadriceps in C60 lower than healthy. Conclusion. In our study, the isokinetic results show a significant difference in performance isokinetic between the healthy and the pathological limb as well as VAS associated with these tests. However, the diversity of outcomes recorded in the patients suggests us that an individualized treatment is the case of patellar tendon pathology. Finally, it would seem that an isokinetic test in eccentric in some patients is, in addition to a test of provocation of the tendon, a pain assessment tool.