Background: The goal of this study was to evaluate the effect of physiotherapy on the strength of muscles responsible for tibial internal rotation (IR) in male patients after anterior cruciate ligament reconstruction (ACLR) using autografts of the semitendinosus and gracilis muscles (STGR).
Material/Methods: Fifty-nine males were examined. The first group consisted of 19 patients subjected to 4-stage physiotherapy following ACLR. The second group consisted of 20 males without knee injuries. The third group consisted of 20 males who had not undergone systematic physiotherapy within the last 12 months following lower limb injuries. Moments of maximal strength (MMS), isometric torque (IT), and peak torque (PT) were measured under static and isokinetic conditions using the Humac Norm System. In the first group, IT measurements were performed during the 13th and 21st week of physiotherapy, while PT measurements were performed during the 16th and 21st weeks of physiotherapy following ACLR. In the control groups (II and III) the measurements were performed once.
Results: In the first group, the IT (13 weeks) and PT (16 weeks) values of internal tibial rotator muscles, obtained from the operated extremities were significantly lower than the values obtained from the uninvolved knees and the control group results. During the 21st week of physiotherapy, the results obtained for IT and PT in patients after ACLR were similar to the values obtained from the uninvolved knees and the results of the second group subjects.
Conclusions: The 21-week physiotherapy in ACLR patients favorably affected the PT values of tibial rotator muscles of the operated knees. In the third group, the IT values did not indicate a complete improvement after 12 months without systematic physiotherapy.

Keywords: Physical Therapy Modalities, Muscle, Skeletal - physiopathology, Muscle Strength - physiology, Knee - surgery, anterior cruciate ligament reconstruction, Anterior Cruciate Ligament - surgery, Rotation, Tibia - physiopathology, Torque