1. Radiographic Findings

Based on the provided X-ray images, the following key features are observed:

• Knee Joint: Generally increased bone density in the femur and tibia, with a relative decrease in the medullary cavity. The joint space is acceptable, no obvious soft tissue swelling, and no clear indication of acute fracture lines.
• Skull: Noticeable thickening of the skullcap, featuring dense cortical bone. The demarcation between the inner and outer tables is not easily discernible, displaying a uniform densification change.
• Spine: Thickened vertebral endplates leading to a “rugger jersey” appearance; dense areas within the vertebral bodies with reduced bone translucency.
• Pelvis: Sclerotic bone in both iliac bones, ischia, and pubic bones, showing a “bone-in-bone” appearance, making it difficult to clearly distinguish the trabecular pattern.

Overall, there is a widespread, highly sclerotic bone pattern, and local “bone-in-bone” signs suggest limited bone remodeling or resorption.

2. Potential Diagnoses

Considering the patient’s age (38 years), the complaint of left knee pain, and the generalized high-density bone findings on imaging, possible diagnoses or differentials include:

1. Adult Osteopetrosis (Osteopetrosis tarda, Albers-Schönberg disease)
   This condition arises from an imbalance between osteoblast and osteoclast activity, leading to generally thickened bone with diminished trabecular translucency. Radiographic findings often include “bone-in-bone” features and increased densities in the spine and thickened skull.
2. Other conditions causing generalized bone overgrowth or sclerosis
   For example, focal osteosclerotic lesions or multifocal osteosclerosis. However, these are often limited to a focal or multifocal distribution, whereas the current case involves generalized changes, especially affecting the skull and long bones, making these less likely.

3. Final Diagnosis

Taking into account the imaging findings, symptoms, patient’s age, and relevant literature, the most likely diagnosis is:

Adult Osteopetrosis (Osteopetrosis tarda / Albers-Schönberg disease).

In adults, osteopetrosis typically presents with milder symptoms and is often discovered incidentally during examinations for other reasons. This patient’s primary complaint of knee pain may be related to localized bone changes or mechanical alignment. Other systemic complications such as nerve compression or fractures are not evident at this time but require regular follow-up for monitoring.

4. Treatment Plan and Rehabilitation

In most adult osteopetrosis cases, specialized treatment is not required, but attention should be given to potential complications and maintaining bone health. Recommendations include:

• Conservative Management and Health Monitoring
  • Regular follow-up: including imaging, complete blood counts, and calcium/phosphorus metabolism assessments.
  • Fracture prevention: Although bones appear sclerotic, their structure may be brittle due to changes in the marrow cavity. Avoid high-impact or high-risk activities.
  • Pain relief: NSAIDs may be used as needed according to medical advice.
• Exercise Prescription and Rehabilitation Training

Following the FITT-VP principle (Frequency, Intensity, Type, Time, Progression, Volume) and adapting to individual tolerance:

• Frequency (F): 3–5 sessions per week.
• Intensity (I): Light to moderate. Target heart rate at about 40%–60% of the maximum, or enough to produce mild sweating and slightly increased breathing while still able to hold a conversation.
• Type (T): Choose low-impact exercises such as brisk walking on level ground, stationary cycling, swimming, or water aerobics to minimize joint stress.
• Time (T): 30–45 minutes per session, adjusted according to joint comfort and overall tolerance.
• Progression (P): Start with a manageable duration and intensity, gradually extending exercise time or slightly increasing intensity. Consider mild resistance training (e.g., light lower limb strength exercises) if needed.
• Volume (V): Monitor the total exercise volume each week. Avoid one-time excessive overload. Integrate daily activities with the rehabilitation program.

If significant pain, swelling, or discomfort arises during any training, exercise should be discontinued and a medical evaluation conducted. If higher-intensity or specialized equipment training is necessary, it should be undertaken gradually under the guidance of a professional rehabilitation therapist or sports medicine specialist.

Disclaimer: This report is a reference-based medical analysis derived from the provided medical history and imaging data. It does not replace in-person consultation or professional medical advice. Specific treatment plans should be determined by the patient’s attending physician, considering clinical evaluations, laboratory results, and additional diagnostic tests.