Background: Low back pain (LBP) is a one of the most common symptoms of vertebral column diseases. Spinal muscles have a outstanding role in maintaining vertebral column function in daily life. But proper function and motion of hip and knee joints also has an important role in performing smooth, fine and nonstressed movements of lumbar spin. Where as accurate and fine motions of hip and knee joints in cooperate with lumbar spin can improve translation and summation of forces and increase performance of movements. The aim of this research is to indicate the amount of interventions of lower limb joints on lumbar spin function in patients with LBP, and attention to physical treatment (PT) of them.

Materials and Methods: Fifty females with LBP due to osteoarthritis ( OA) of lumbar spin participated in this study and divided in two groups randomly with similar number of cases: a) ordinary treatment or control group and b) complementary treatment group. Patients in control group treated by routine PT approach ( superficial heat, ultrasound, TENS, forward flexion and back extension exercises ) and patients in complementary or test group received routine treatment similar to control group and also strength and stretching exercises of hip and knee joint muscles ( latisimous dorsi, gluteous maximus, iliopsoas, quadriceps and hamstring ) bilaterally. Range of motion (ROM) of lumbar, hip and keen joints by valid goniametere and pain of lumbar in motions at all of axis by visual analog scale measured before, after five and ten sessions of treatments in both groups.

Results: In control group with non parametric tests there was not significant difference of MMT of muscles and ROMs of hip and knee joints. Lumbar pain in motion after ten sessions of PT in this group reduced significantly ( P< 0.05 ). Increase of lumbar motion in all of axis after PT was significant at this patients ( P< 0.05 ). In second group that received complementary treatments; ROM of joints, lumbar pain had significant differences between onset of treatments and five and ten sessions later ( P< 0.05 ), but there was not significant findings in MMT of muscles. There were significant differences between percentages of reduce of pain and increase of ROM in comparison of two groups ( P< 0.05 ). Where as patients that received ordinary PT and strength and stretching of muscles around of hip and knee indicated better recovery signs.

Conclusion: Reduce of lumbar pain with improve of motion and flexibility of muscles such as quadriceps, hamstring, gluteus maximus, iliopsoas and latisimous dorsi in a complete physical therapy approach indicate there are a great correlation between lumbar pain and functionality of lower limb joints. Therefore concentration to flexibility and extensibility of muscles of lower limbs is a basis aim in treatment of patients with lumbar OA.