Mitochondrial ROS regulate oxidative damage and mitophagy but not age-related muscle fiber atrophy

Age-related loss of skeletal muscle mass and function is a major contributor to morbidity and has a profound effect on the quality of life of older people. The potential role of age-dependent mitochondrial dysfunction and cumulative oxidative stress as the underlying cause of muscle aging remains a controversial topic. Here we show that the pharmacological attenuation of age-related mitochondrial redox changes in muscle with SS31 is associated with some improvements in oxidative damage and mitophagy in muscles of old mice. However, this treatment failed to rescue the age-related muscle fiber atrophy associated with muscle atrophy and weakness. Collectively, these data imply that the muscle mitochondrial redox environment is not a key regulator of muscle fiber atrophy during sarcopenia but may play a key role in the decline of mitochondrial organelle integrity that occurs with muscle aging

Reconstruction of the extensor mechanism after major knee resection.

In periarticular knee resections, the relative lack of soft tissue coverage and need to reattach the extensor mechanism after en bloc resection of the tibial tuberosity with the tumor specimen complicate reconstructions and decrease postoperative function and stability of the knee joint. Distal femoral reconstructions are less problematic; muscular attachments are relatively few, neurovascular structures are not immediately adjacent to bone, and the knee extensor mechanism is usually not compromised from bone tumors. In the proximal tibia, the close proximity of the neurovascular structures in the popliteal fossa and peroneal nerve at the lateral aspect of the leg make reconstruction more difficult. Poor function is mostly related to unreliable options for knee extensor mechanism reattachment and poor soft tissue coverage. Successful and reliable attachment of the soft tissues has been a significant advance that improved functional outcomes. This article describes techniques for the reconstruction of the extensor mechanism of the knee after proximal tibia resections. Combined reconstruction techniques using direct reattachment of the patellar tendon with synthetic materials to megaprosthetic or allograft reconstructions for immediate stability, augmentation with autologous bone graft or substitutes at the attachment site, and coverage with the medial gastrocnemius muscle flap and supplementary flaps for long-term stability of the reattachment are currently considered the gold standard

Osteosarcoma invasion of the inferior vena cava and right atrium.

We present a woman with chondroblastic osteosarcoma of the left ilium extending to the L4 epidural space and invading the inferior vena cava and right atrium, misdiagnosed as deep venous thrombosis. After neoadjuvant chemotherapy, two stage resection was planned. During the anterior approach, a mass in the left common iliac vein and inferior vena cava was found and tumor thromboembolism was diagnosed. Frozen sections showed chondroblastic osteosarcoma. The patient denied further surgery and had palliative intensity modulated radiation therapy

Osteosarcoma invasion of the inferior vena cava and right atrium.

We present a woman with chondroblastic osteosarcoma of the left ilium extending to the L4 epidural space and invading the inferior vena cava and right atrium, misdiagnosed as deep venous thrombosis. After neoadjuvant chemotherapy, two stage resection was planned. During the anterior approach, a mass in the left common iliac vein and inferior vena cava was found and tumor thromboembolism was diagnosed. Frozen sections showed chondroblastic osteosarcoma. The patient denied further surgery and had palliative intensity modulated radiation therapy

Outcome of the intramedullary diaphyseal segmental defect fixation system for bone tumours.

Background: Resection of diaphyseal malignant bone tumors is indicated for local control and impending pathological fracture or failure of prophylactic internal fixation. However, there are no large, long-term studies analyzing the results of intercalary reconstruction using segmental metallic spacers. Materials and Methods: We present 24 patients treated with wide resection for primary or metastatic bone tumors involving the diaphysis of the femur, tibia, or humerus and reconstruction using a modular intramedullary diaphyseal segmental defect fixation system. The mean length of bone resection was 10 cm. The postoperative complications and outcome were evaluated. Results: At a mean follow-up of 29 months, 17 patients were alive and 7 patients were dead of disease; no patient had local recurrence. Implant-related complications occurred in 8 patients, the most common being mechanical loosening and rotational instability. Loosening was most common in reconstructions of more than 10 cm length of bone resection. In all femoral reconstructions, mechanical failure occurred at the proximal stem. True limb length discrepancy of 2.0 cm was observed in one patient. Wound healing complications were not observed; range of motion and function of the adjacent joints was within normal limits. Conclusions: The modularity, ease of application and preservation of the adjacent joints are major advantages of segmental modular prostheses; however, the complications' rate is high. Complications occur most often at the proximal stem in femoral reconstructions and reconstructions for more than 10 cm length of bone resection. In these cases, the use of these implants should be reconsidered or not recommende