Medical Imaging Analysis Report

I. Imaging Findings

MRI images of the patient’s left knee joint show abnormal soft tissue signals with lobulated, frond-like projections within the joint cavity. On T1WI, high-signal areas are visible; on T2WI, the signal is relatively high but slightly lower than T1WI. On fat-suppressed sequences, the signal decreases. Overall, these findings resemble fat signal characteristics. Joint effusion is observed, and no significant bony destruction or marked bone erosion is noted.

These imaging features suggest synovial proliferation and fat deposition within the joint, forming lobulated, frond-like structures, with no obvious calcification or bone destruction.

II. Possible Diagnoses

1. Lipoma arborescens: Typically manifests on imaging as synovial thickening and fat deposition in a frond-like pattern, with high signal on T1 and suppression on fat-suppressed sequences. Commonly found in the knee joint.
2. Pigmented Villonodular Synovitis (PVNS): Can also present with synovial proliferation, but usually shows lower signals on T1WI and often features hemosiderin deposition. The imaging findings in this case are not entirely consistent with PVNS.
3. Synovial Chondromatosis: May present with nodular synovial proliferation in the joint and often includes chondroid or calcified bodies. Imaging typically reveals calcifications or cartilage signals, which do not match the fat signal pattern in this case.
4. Other Soft Tissue Tumors (e.g., Liposarcoma): While these may contain fatty components, they often show more aggressive features such as irregular lesion borders or significant soft tissue destruction.

Given the absence of a significant trauma history, the presence of fat-like signals, and the frond-like synovial proliferation confined to the joint cavity, the findings most closely align with the typical presentation of lipoma arborescens.

III. Final Diagnosis

Considering the patient’s age, clinical presentation (chronic joint swelling, limited range of motion), and MRI findings (lobulated fatty signals, accompanying joint effusion), the most likely diagnosis is: Lipoma arborescens.

IV. Treatment Plan and Rehabilitation

1. Treatment Recommendations

• Conservative Management: If symptoms are mild, observation can be considered. Use non-steroidal anti-inflammatory drugs (NSAIDs) to control joint pain and effusion, supplemented by local physical therapy or acupuncture for symptomatic relief.
• Surgical Treatment: For persistent symptoms or significant limitation of joint movement, arthroscopic synovectomy may be considered. This procedure can help alleviate joint pain and improve mobility.

2. Rehabilitation and Exercise Prescription

Rehabilitation should follow a gradual, individualized approach (the FITT-VP principle: Frequency, Intensity, Time, Type, Progression, and Volume).

1. Preoperative/Conservative Management Phase:
   • Frequency: 3–4 times per week.
   • Intensity: Mild to moderate, ensuring not to exacerbate joint pain.
   • Time: 20–30 minutes per session, including warm-up and cool-down exercises.
   • Type: Focus on non-weight-bearing or reduced weight-bearing training such as cycling, swimming, or hydrotherapy. Incorporate quadriceps isometric contractions to maintain muscle strength.
2. Postoperative Rehabilitation Phase (If Synovectomy is Performed):
   • Early Stage (1–2 weeks post-op): Emphasize passive range-of-motion exercises. Cold therapy and analgesics may be used to reduce inflammation.
   • Mid Stage (3–6 weeks post-op): Gradually increase weight-bearing exercises, such as seated leg raises and small-range flexion/extension movements. Avoid vigorous bending and stretching; water-based rehabilitation can be added.
   • Late Stage (7–12 weeks post-op): Steadily improve muscle strength and joint stability with cycling, resistance band exercises, and coordination training, progressively returning to regular activities.
   • Advanced Stage (beyond 3 months post-op): If recovery is adequate, activities like light jogging or badminton can be introduced at moderate intensity, while monitoring joint response.
3. Throughout the rehabilitation process, follow-up is required to adjust the intensity and methods based on joint response.

Disclaimer

This report is based on the existing imaging and clinical information for a preliminary analysis and is provided for reference only. The specific diagnosis and treatment plan should be determined by a professional physician through an in-person consultation and comprehensive assessment of the patient’s actual condition.