Experimental: Group A: Ultrasound therapy combined with Chitosan nanoparticles gel and Exercises Program

In this group will receive ultrasound therapy coupled with chitosan-nanoparticles gel with an exercises program. The US protocol which will consist of pulsed ultrasound waves. The parameters that will be selected consists of; frequency of 1 MHz, 1 W/cm2 power delivered at an intensity of an intensity of 2.5W/ cm2 and with duty cycle of 25% and will be applied with a 5-cm diameter applicator.~The area of treatment will be cleaned to permit an effective skin applicator coupling. Each patient will be placed in a supine position for the application of ultrasound. A suitable palpation to locate the discomfort source and some passive motions to identify a range of motion restriction will be completed prior to the ultrasound application.~Ultrasound will be applied to the medial and lateral aspects of the knee in circular motions, with the probe at right angles to ensure maximum absorption of energy. Each session will last for 5 minutes.

Active_comparator: Group B: Application of Extracorporeal Shockwave and Exercises Program:

This group will receive ESWT with an exercises program. Subjects will receive 5 sessions, one week apart. Before the treatment, subjects will be placed in supine to expose and prepare the treated area with the knee flexed at angle of 90° and the hip is abducted and externally rotated. The impulses will be applied on the subchondral bone at the medial and lateral tibia condyle at 2.0 cm below the joint line in anteroposterior view and 2.0 cm from the medial skin edge in lateral view. The treatment application will be as follows: 2000 impulses will be administered at (EFD) with an energy flux density ranging from 0.22-0.43 mJ / mm2 at 8 Hz. In which 0.22 mJ/mm²: likely corresponds to around 1.5-3 bars, while 0.43 mJ/mm² likely corresponds to around 3-5 bars. The probe was chosen effective treatment depth (5-20-mm focal depth), semi-movable technique of the shockwave applicator and 5 minutes duration.

Placebo_comparator: Group C: Exercises Program

Patients in this group will receive only an exercises program for 3 times weekly for 4 weeks. This program includes:~(1) Warming-up (5 min); (2) strengthening exercises for the lower limbs: 3 sets of 15 repetitions: flexion SLR, abduction SLR, and extension SLR, standing knee flexion, quadriceps isometrics, 10 repetitions of 5 s, 0° and 30°; (3) aerobic exercise on a stationary bike (20 min), (4) and stretching (5 min) with a weekend break.~All patients in the three groups (A, B and C) will receive the same exercise program.