I. Imaging Findings

1. The local structure of the left medial segment of the clavicle (near the sternal end) appears irregular, suggesting a possible fracture or fracture line;
2. Noticeable soft tissue swelling in the adjacent area with increased density, indicating localized hematoma or blood infiltration signs;
3. Possible contrast extravasation in the arterial phase, suggesting active bleeding;
4. No obvious fracture signs detected in the rib sequence or the rest of the thoracic cage;
5. No apparent pneumothorax or large-scale parenchymal damage in the lung fields, and no evident mediastinal widening; however, carefully rule out potential hematoma involving mediastinal structures;
6. Other observed structures (such as the scapula, thoracic vertebrae, etc.) appear without significant morphological or structural abnormalities.

II. Potential Diagnoses

1. Medial Clavicle Fracture with Arterial Injury
   Imaging suggests a possible fracture at the medial end of the clavicle with significant soft tissue swelling and signs of active bleeding. The patient’s use of anticoagulant (Rivaroxaban) increases the risk of hemorrhage. Therefore, suspicion is high for a clavicle fracture with tearing or injury to nearby arterial branches (e.g., branches of the thoracoacromial artery) leading to bleeding.
2. Chest Wall Hematoma (Arterial Bleeding)
   Rapidly progressing chest wall swelling could originate from a chest wall artery, including intercostal arteries or branches of the thoracoacromial artery. Arterial-phase contrast extravasation indicates bleeding from an arterial branch. Even without a clear fracture, this should be considered; however, a clavicle fracture or instability substantially raises the likelihood of vascular damage.
3. Other Vascular Lesions at the Cervicothoracic Junction (e.g., Pseudoaneurysm)
   If the fracture segment or traumatic stimulus leads to arterial wall injury, a pseudoaneurysm or localized bulge could form. However, acute bleeding symptoms are more consistent with a sudden arterial disruption rather than a chronic pseudoaneurysm.

III. Final Diagnosis

Based on the patient’s history of trauma (bicycle accident), anticoagulant use, the suspected medial clavicle fracture on imaging, arterial-phase contrast extravasation in the soft tissues, and a rapidly progressing local hematoma, the findings most likely indicate:

"Left Medial Clavicle Fracture with Associated Injury and Bleeding of the Thoracoacromial Artery (or its branches)"

This corresponds with documented cases of high-energy trauma and medial clavicle fractures accompanied by vascular injury. Further assessment of the bleeding source or the extent of vascular damage may require interventional angiography or surgical exploration as indicated by clinical need.

IV. Treatment Plan and Rehabilitation Program

1. Treatment Strategy

1. Emergency Hemostasis and Endovascular Treatment
   – For patients with active arterial bleeding, urgent angiography and selective arterial embolization are recommended. If bleeding is significant or hematoma expansion is rapid and difficult to control, surgical exploration for hemostasis may be considered;
   – Ongoing or adjusted anticoagulant therapy must be evaluated by specialists, balancing the patient’s underlying conditions with the current risk of bleeding.
2. Fracture Management
   – If the clavicle fracture is significantly displaced or associated with vascular injury, an orthopedic consultation is warranted; open reduction and internal fixation (ORIF) may be required;
   – If there is no severe displacement, conservative management (e.g., sling or figure-of-eight bandage) can be used with close monitoring of the wound, hematoma, and neurovascular status.
3. Supportive Treatment
   – Pain management: Use analgesics and physical therapy measures to alleviate pain;
   – Infection prevention: Prevent secondary infection of the hematoma;
   – Cardiopulmonary function assessment: Especially in older patients, provide proper supportive therapy if needed.

2. Rehabilitation and Exercise Prescription

Rehabilitation training should account for the advanced age of the patient, chest trauma, and possible osteoporosis, progressing gradually to avoid excessive traction.

1. Early Stage (within 1–2 weeks post-surgery or acute phase)
   – Main goals: Alleviate pain, prevent joint stiffness;
   – Mode of exercise: Passive or assisted active movements of the shoulder and elbow joints, avoiding large ranges of motion;
   – Frequency: 2–3 times a day, 5–10 minutes each time, adjusted according to pain tolerance.
2. Mid Stage (2–6 weeks)
   – Main goals: Promote fracture healing, maintain muscle strength, and gradually restore range of motion;
   – Mode of exercise: Within the limits of pain control, progressively increase shoulder mobility exercises and muscle strengthening (e.g., light resistance with elastic bands);
   – Frequency: 3–4 times a week, 15–20 minutes each session, appropriately increasing resistance and range of motion.
3. Late Stage (after 6 weeks)
   – Main goals: Strengthen the shoulder girdle and chest muscles, improve upper limb function;
   – Mode of exercise: Gradually add moderate-intensity upper limb resistance exercises, functional training simulating daily activities;
   – Frequency: 3–5 times a week, 20–30 minutes each session, progressing under the guidance of a physician or therapist according to fracture healing status.

Throughout the rehabilitation process, monitor for pain, swelling, and neurovascular symptoms. If any abnormality occurs (e.g., hematoma expansion, severe pain), seek immediate medical advice or contact the attending physician.

Disclaimer:

This report is a reference analysis based on current imaging and clinical information and does not substitute for in-person consultation or a certified medical professional’s diagnosis and treatment advice. If you have any questions or if your condition changes, please seek medical attention promptly.