Osteosarcoma, a rare malignant bone tumor, typically develops in the osteoblast cells that form bone, presents unique challenges when localized in the distal femur, particularly in adolescents and young adults ^[1]. This case aims to provide a detailed exploration of the diagnostic journey and the efficacy of a multidisciplinary approach in managing this complex condition. Distal femur osteosarcoma, constituting about 10–15% of all osteosarcomas, predominantly affects the pediatric age group ^[2]. The diagnosis relies on a combination of clinical, radiological, and histopathological assessments. Previous studies have emphasized the aggressive nature of distal femur osteosarcoma, necessitating a carefully planned and executed treatment strategy ^[3]. Extracorporeal radiotherapy (ECRT) is generally considered for patients with osteosarcoma when: (a) There is a high risk of local recurrence, (b) limb preservation is a priority, and other options are not viable, and (c) the patient is a suitable candidate for the procedure from a medical and surgical perspective. ECRT represents a specialized and innovative approach in the multidisciplinary treatment of osteosarcoma, offering a potential limb sparing option for patients. However, it requires careful consideration of the risks and benefits, as well as meticulous surgical and post-operative management to optimize outcomes.

The patient, a 15-year-old male, presented with localized pain and swelling in the distal femur, prompting a thorough evaluation. Understanding the unique challenges associated with osteosarcoma in the pediatric population is crucial for tailoring effective treatment strategies. Adolescents often face distinct physiological and psychological challenges, and their response to treatment may differ from that of adults. In this case, the age of the patient played a significant role in treatment decision-making, with considerations for growth plate preservation and long-term functional outcomes Fig. 1. The decision for pre-operative neoadjuvant chemotherapy consisting of 3 cycles was pivotal in preparing the patient for the subsequent surgical intervention ^[4]. Distal femur osteosarcoma commonly presents with localized pain and swelling. Radiological assessments, including magnetic resonance imaging (MRI), are instrumental in determining tumor extent and planning surgical interventions. The incorporation of advanced imaging techniques aids in precise staging, facilitating an optimal treatment plan.

The surgery, performed on December 16, 2020, involved an en bloc excision of the tumor through a swashbuckler surgical approach ^[5]. This technique, chosen for its accessibility and minimal soft tissue disruption, aligns with the goal of achieving complete tumor excision while preserving surrounding structures. The meticulous excision, with a 5 cm proximal healthy margin, aimed to minimize the risk of local recurrence, a critical consideration in osteosarcoma management ^[6] Fig. 2 and 3.

Management and treatment

The surgical intervention, performed on December 16, 2020, marked a significant milestone in the patient’s journey ^[7]. The en bloc excision of the tumor through a swashbuckler surgical approach ensured the removal of the tumorous bone with a 5 cm proximal healthy margin. This meticulous approach aimed to minimize the risk of local recurrence.

This case report of a 15-year-old male diagnosed with distal femur osteosarcoma underscores the significance of a multidisciplinary approach in achieving successful outcomes. The comprehensive diagnostic journey, encompassing pathological markers, radiological investigations, and histopathology, allowed for an accurate diagnosis and informed subsequent treatment decisions. Extracorporeal irradiation presents a limb salvage technique for osteosarcoma cases where there’s adequate remaining bone both proximal and distal to the tumor. This method, deemed oncologically safe with favorable functional outcomes, utilizes a radiation dose of 50 Gy to effectively sterilize the bone, eliminating tumor cells while mitigating adverse impacts on bone biomechanics and biology. Employing suitable implants for internal fixation alongside supplementary bone grafting during the initial surgery may diminish the necessity for subsequent interventions to achieve union. However, it is essential to note that this procedure is not suitable for structurally weak tumor bones or bones with pathological fractures ^[8]. ECRT of the excised bone fragment is a novel strategy employed to eradicate any remaining tumor cells  ^[10]. This technique involves subjecting the excised bone to a high dose of radiation outside the body, ensuring thorough eradication of malignant cells. The subsequent reimplantation of the bone fragment using an autologous fibula graft is a critical step in restoring skeletal integrity ^[1]. The subsequent ECRT of the excised bone fragment is a unique strategy employed to eradicate any residual malignant cells ^[11]. This approach adds an extra layer of assurance against local recurrence, contributing to the overall success of the treatment Fig. 4. The reimplantation of the bone fragment using an autologous fibula graft and fixation with a distal femur anatomical locking plate system represent cutting-edge reconstructive techniques. The use of anatomical locking plates aligns with contemporary orthopedic practices, ensuring stability and facilitating early mobilization. In this approach, the soft tissues are well preserved and there is no injury to any ligaments and there is no knee instability of any kind and the knee biomechanics is well preserved Fig. 5. Sequential follow-ups from the immediate post-operative period until January 2024 have been integral in assessing the patient’s recovery trajectory The absence of complications and the achievement of full knee extension, coupled with the improvement in knee flexion to 0–70 degrees, speak to the efficacy of the chosen treatment modalities Fig. 6-8. These follow-ups provided a platform for monitoring the psychosocial well-being of the adolescent patient ^[10] Fig. 9 and 10.

The successful management of distal femur osteosarcoma in adolescents necessitates a thorough understanding of the patient’s unique profile and a multidisciplinary approach. This case exemplifies the integration of advanced diagnostics, innovative surgical techniques, and meticulous follow-up, resulting in a positive clinical outcome. The sequential follow-ups and insights into the current lifestyle status emphasize the importance of not only treating the disease but also addressing the holistic well-being of the adolescent patient.

In the battle against bone osteosarcoma, ECRT plays a key role alongside surgery. This approach involves temporarily extracting the tumor, subjecting it to radiation externally, and then reinserting it with care. Prioritizing limb preservation, it not only targets cancer effectively but also offers patients optimism and resilience, guiding them toward healing and hope throughout their treatment journey.