This study will be conducted to investigate the effect of selected therapeutic exercises compared to standard exercise program in improving ROM, muscle strength and functional outcomes in distal femur osteosarcoma patients who have undergone tumor resection and modular knee endoprosthesis.

Osteosarcomas (OS) are the most common primary bone tumor and third most common cancer among children and adolescents after lymphomas and brain cancers (Wang et al., 2018; Luetke et al., 2014).

It is a primary malignant bone tumor with a worldwide incidence of 3.4 per million people per year (Mirabello et al., 2009). They are characterized by the production of osteoid, or immature bone, by malignant mesenchymal cells (Wang et al., 2018; (Luetke et al., 2014).

Patients displayed some persisting physical difficulties including incapability to perform active range of motion (ROM), decreased muscle strength, altered gait and sit-to-stand patterns, yet they maintained high levels of emotional acceptance and coping. A surprising but important finding was the persisting hip weakness in both operated and non-operated limbs, which extends up to 42 months after resection around the knee. This indicates that continued rehabilitation programs emphasizing hip strengthening should be considered for these patients, even years after surgery (Beebe et al., 2009). Furthermore, ROM exercises, strengthening exercises and balance exercises improve overall Quality of life (QOL) for these patients (Marchese et al., 2006).

Inclusion Criteria:

1) Patients diagnosed as distal femur osteosarcoma. 2) Age of the patient from 15-50 years old 3) Patients undergoing tumor resection and knee endoprosthetic reconstruction six weeks ago. 4) Both gender

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Exclusion Criteria:

1) Lung and bone metastasis 2) End stage patients receiving palliative chemotherapy 3) Patients undergoing L.L amputation or rotationplasty (any surgical procedures rather than knee endoprosthetic reconstruction). 4) Local tumor recurrence 5) Sever psychiatric illness 6) Heart disease or any condition that prevent the patient from participation in exercise

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