Internal derangement of the knee

Disease Description (Causes and Symptoms)

• Definition: Internal derangement of the knee refers to a condition in which the alignment and movement within the joint become abnormal due to damage to or functional abnormalities of structures inside the knee joint (the cruciate ligaments, collateral ligaments, meniscus, articular cartilage, etc.).
• Causes: The main causes include trauma (sports injuries, falls, traffic accidents), repetitive overuse (excessive impact on the knee), and degenerative changes (age-related changes in the cartilage and meniscus).
• Pathophysiology: Ligament tears or meniscal injuries cause loss of joint stability and abnormal movement (abnormal rotation and forward-backward displacement), resulting in articular cartilage damage and inflammation. Joint effusion (increased synovial fluid) causes swelling and pain, and if left untreated, the condition may progress to chronic instability and degenerative arthritis (osteoarthritis).
• Main symptoms: Knee swelling (joint effusion), knee pain (especially with weight-bearing), a feeling of joint instability (a feeling that the knee is about to give way), catching or locking of the joint, or limited movement. In acute injuries, the knee often swells immediately and the pain becomes severe.

Treatment Methods

• Conservative treatment
  • Acute phase: RICE (Rest, Ice, Compression, Elevation), with control of swelling and management of pain.
  • Medication: Nonsteroidal anti-inflammatory drugs (NSAIDs) to relieve pain and inflammation. Pain relievers may be used for a short period if necessary. Antibiotics may be used if infection is suspected (depending on the diagnosis).
  • Braces and casts: Stabilization of the joint (knee supports and functional braces) to reduce pain and prevent additional damage.
  • Physical therapy (rehabilitation): Strengthening exercises (especially the quadriceps), restoration of joint mobility, balance and neuromuscular control training, and gradual recovery of weight-bearing ability.
  • Intra-articular injections: Steroid injections (short-term reduction of inflammation) or hyaluronic acid injections (lubrication and symptom relief) may be used selectively (depending on the indications).
• Surgical treatment
  • Arthroscopy: Diagnosis and treatment (meniscal repair/resection, smoothing of the cartilage surface, removal of loose bodies, etc.) performed through small incisions. Recovery is faster and complications are less common.
  • Ligament surgery: For a completely torn anterior cruciate ligament (ACL), reconstruction (using an autograft or allograft) may be considered. The treatment decision depends on the patient's activity level and degree of instability.
  • Other: If there is severe articular cartilage loss or advanced age and extensive degenerative changes, arthroscopic debridement followed by conservative management or joint replacement surgery (partial or total replacement) may be considered.
• Precautions, risk of complications, and self-care
  • After an acute injury, avoid activities that immediately place weight or rotational force on the knee (risk of additional damage).
  • After surgery, diligently follow the prescribed rehabilitation plan (unauthorized early activity may lead to treatment failure or reinjury).
  • Because cartilage damage may progress over the long term, joint protection (weight management and muscle strengthening) and regular follow-up are necessary.
  • Surgical complications may include infection, blood clots (deep vein thrombosis), joint stiffness, and nerve or blood vessel damage. Although arthroscopy is minimally invasive, complications are still possible.

Outpatient Visit Checkpoints (What to Bring, Records, and Example Questions)

• Items to bring (recommended)
  • A list of all medications currently being taken (including dosage and dosing times), and whether aspirin or anticoagulants are being taken
  • Past medical history and surgical records (especially records of knee surgery)
  • Original copies or CDs of recent test results and imaging (MRI, X-ray, ultrasound, medical certificates)
  • History of allergies (including medications and anesthesia)
• Symptom records (prepare before the appointment)
  • When the symptoms began and the circumstances in which they occurred (posture and movement at the time of the injury)
  • Characteristics of the pain (location and intensity of pain, changes with weight-bearing, and whether locking or instability is present)
  • Pattern of swelling (whether swelling occurred immediately or after several hours or days)
  • Previous treatments (physical therapy, medication, injections, etc.) and the response to them
  • Restrictions and goals in daily life and exercise (such as the desire to return to sports)
• Examples of materials to show the doctor during the outpatient visit: a pain diary (pain scores and changes by activity), recent imaging, and a medication list

Examples of General Questions to Ask the Doctor

• "What is the exact cause and extent of my knee injury?"
• "Do I need an MRI? What additional tests are needed?"
• "Is improvement likely with conservative treatment, or is surgery recommended?"
• "What are the benefits and risks (side effects) of the recommended treatment?"
• "How long is the expected time until I can return to daily activities and sports after treatment?"
• "What self-care measures can I take to reduce the risk of recurrence and complications (such as arthritis)?"

Examples of Disease-Specific Questions

• "A meniscal tear is suspected. Is this an injury that can be repaired, or would partial resection (meniscectomy) be more appropriate? What are the criteria for choosing between them?"
• "If the anterior cruciate ligament (ACL) is completely torn, do you recommend reconstruction? Between an autograft (patellar tendon or hamstring tendon) and an allograft, which option is more suitable for my activity level (e.g., soccer)?"

If you would like, you can also provide your current symptoms and test results (such as MRI findings), and we can organize more specific diagnostic and treatment directions and preparation requirements.