The purpose of this study is to investigate the effect of overdose ultrasound on the articular cartilage of the osteoarthritic knee in adult albino rate. The US is considered the most popular and effective treatment for osteoarthritis as it can penetrate deep tissue reaching internal structures which allow it to be effective for osteoarthritis treatment. Previous researches apply US as a treatment for different cases with different intensity and repetition, but no one has actually proven the frequency of this use or the effect of excess use on cells, so the investigators need evidence to determine the optimum therapeutic dose and frequent repetition which should determine the effect of more than one session on the joint cartilage and cells and if it has a positive or negative effect and this is the main goal in this study which is limited in all studies concerning the US.

Because many patients suffer from osteoarthritis and this work may help for treatment those patients. The US is considered the most popular and effective treatment for osteoarthritis as it can penetrate deep tissue reaching internal structures which allow to be effective for osteoarthritis treatment, also improves the cellular function by making microscopic gas bubbles near to the site of injury expand and contract rapidly, a process called cavitation. This process is thought to speed up the healing process in the injured body part. Previous researches apply US as a treatment for different cases with different intensity and repetition, but no one has actually proven the frequency of this use or the effect of excess use on cells, so the investigators need evidence to determine the optimum therapeutic dose and frequent repetition which should determine the effect of this repetition on the joints and cells and if has a positive or negative effect and this is the main goal in this study which is limited in all studies concerning the US in addition to previous systematic reviews regarding its effectiveness on KOA are outdated, and the latest reviews presented methodological limitations, such as the inclusion of mixed interventions, that hindered the evidence synthesis, and the inclusion of pulsed US (low-intensity) only.

The Investigators want to perform a more focused and comprehensive evidence synthesis targeting the isolated effects of the therapeutic US and specially the overdose to more clearly define its contributing role as an adjuvant treatment in rehabilitative regimens for KOA. Therefore studies worked on the effect of ultrasound on the knee cartilage especially femoral cartilage, the degradation and destruction of the femoral articular cartilage demonstrated a greater degree of deterioration than those of the tibial and patellar articular cartilage, and on some specific changes within its cells like apoptosis neglecting other cellular or matrix changes which may be affected by the destruction of articular cartilage and it's the second aim in this study. Although the results of previous studies suggest that US is a safe non-pharmacological treatment option that may provide additional pain relief and functional improvement in addition to cartilage repair with different parameters of US, no research assessing dosing regimen repetition to investigate its overdose effect on tissues and this was not reasonable to perform these analyses based on overdose on humans. This is the topic for the research, because the optimum therapeutic dose of therapeutic US is debated in previous research.

Inclusion Criteria:

• Forty male Albino rats will be used for the study of knee osteoarthritis.
• At 7-8 weeks of age.
• 200-250 grams in weight will be obtained from the animal facility of the histology department, Faculty of Medicine, Tanta University.

Exclusion Criteria:

• Weight < 200-250 > kg.
• Rats with injured thighs and/or knees.
• Female rats.

40 rats