Background: The aim of the study was to assess the activity of the vastus lateralis (VAL) and vastus medialis (VAM) within 3-5 years after anterior cruciate ligament (ACL) reconstruction with a LARS synthetic ligament (the Ligament Advanced Reinforcement System) compared to muscle activity in the non-operated limb and in the limbs of the controls during selected functional tests.
Material and methods: 20 men after ACL reconstruction using LARS synthetic ligament were qualified to the study group. The control group included 20 healthy men. Lysholm scale used to assess the functionality of the knee joint. To test muscle activity, TELEMYO DTS surface electromyography (sEMG) recording kit by Noraxon was used. The examined muscles on both limbs were the VAL and the VAM. The subjects were asked to perform the test-movements (dynamic ascent and descent from 25 cm step and slowly squats).
Results: Statistically significant differences were noted only for the values of VAL SA_SD (the quotients of mean sEMG values of the VAL muscle during step ascent - SA and descent -SD; Z=2.83; p=0.0047) and VAM SA_SD (Z=1.98; p=0.0401) parameters. In each analyzed parameter higher values were recorded among people from the control group. Weak but significant correlations were found between the VAL and VAM: SA_SD and the results obtained on the Lysholm Scale.
Conclusions: 1. In the group of patients after LARS, quadriceps activity disorders persisted in tested dynamic activities. 2. In the therapy planning or sports training in the distant period after ACL reconstruction with LARS, emphasis should be placed on quadriceps muscle training, and the sEMG test may be helpful in optimizing the management strategy.
Keywords: LARS; Lysholm scale; quadriceps muscle; surface electromyography (sEMG).