Knee Swelling After Surgery: Common Causes, Serious Complications, and Management

Why is my knee still swollen 5 weeks after surgery?

Persistent knee swelling five weeks post-surgery is not uncommon, often indicating ongoing inflammation from the healing process or a sign that the rehabilitation intensity needs adjustment. While typically part of recovery, it warrants attention to rule out less common complications and ensure optimal progression.

Understanding Post-Surgical Swelling

Swelling, or edema, is a natural and often necessary component of the body's healing process. Following knee surgery (e.g., ACL reconstruction, meniscus repair, total knee arthroplasty), the body initiates an inflammatory response to clear damaged tissue and begin repair. This involves increased blood flow, fluid accumulation, and the migration of immune cells to the surgical site. While initial swelling is expected and typically peaks within the first few days to weeks, its persistence at five weeks can be concerning for patients. Understanding the underlying causes is crucial for effective management and a successful recovery.

Common Causes of Persistent Swelling at 5 Weeks

At five weeks post-surgery, several factors commonly contribute to ongoing knee swelling:

• Normal, Protracted Healing Process: Even at five weeks, the inflammatory phase of healing may still be active, especially if the surgery was complex or involved significant tissue trauma. The body is still working to resorb internal bleeding, fluid, and cellular debris.
• Overactivity or Premature Loading: One of the most frequent culprits is doing "too much, too soon." Engaging in activities that place excessive stress on the healing joint, such as prolonged standing, walking long distances, or pushing too hard in physical therapy, can re-aggravate the surgical site and trigger a renewed inflammatory response.
• Insufficient Elevation and Compression: Adherence to the R.I.C.E. (Rest, Ice, Compression, Elevation) protocol is paramount in the early weeks. If elevation of the leg above heart level is not consistently maintained, especially during rest, gravity will continue to pull fluid into the knee joint and surrounding tissues. Similarly, inadequate or inconsistent compression (e.g., with an elastic bandage or compression sleeve) can hinder fluid removal.
• Muscle Weakness and Impaired Lymphatic Drainage: The muscles surrounding the knee, particularly the quadriceps and calf muscles, play a vital role in pumping lymphatic fluid and blood back towards the heart. Post-surgical pain, disuse, and immobilization can lead to muscle atrophy and reduced muscle pump function, impairing the natural drainage of fluid from the knee.
• Fluid Accumulation within the Joint (Effusion): Sometimes, the synovial lining of the joint continues to produce excess fluid in response to ongoing irritation or inflammation. This can lead to a noticeable "fullness" or balloon-like appearance of the knee.

Less Common, More Serious Causes

While less frequent, persistent swelling could also indicate a more serious underlying issue that requires immediate medical attention:

• Infection: A surgical site infection can manifest as persistent swelling, often accompanied by increased pain, redness, warmth, fever, and possibly purulent drainage. Even a low-grade infection can cause significant inflammation.
• Deep Vein Thrombosis (DVT): A blood clot in the deep veins, usually of the calf or thigh, can cause swelling in the leg, including the knee. Other signs may include pain, tenderness, warmth, and discoloration in the calf. DVT is a serious condition requiring urgent medical evaluation.
• Arthrofibrosis (Excessive Scar Tissue Formation): In some cases, the body produces an excessive amount of scar tissue within the joint, leading to a condition called arthrofibrosis. This dense scar tissue can restrict joint movement, cause pain, and perpetuate inflammation and swelling.
• Re-injury or New Meniscus/Ligament Tear: Accidental re-injury, such as twisting the knee or falling, can cause new damage (e.g., a re-tear of the meniscus or a new ligament sprain) that results in acute swelling on top of the existing post-surgical inflammation.
• Complex Regional Pain Syndrome (CRPS): This is a rare, chronic pain condition that can develop after injury or surgery. It involves severe pain, swelling, skin changes (temperature, color), and functional impairment, disproportionate to the initial injury. Swelling is a hallmark symptom.

When to Seek Medical Attention

While some persistent swelling is normal, certain signs warrant immediate contact with your surgeon or medical team:

• Sudden increase in swelling that doesn't resolve with rest, ice, and elevation.
• New or worsening pain that is severe or not controlled by prescribed medication.
• Increased redness or warmth around the incision site or throughout the knee.
• Fever or chills.
• Pus or foul-smelling drainage from the incision.
• Calf pain, tenderness, or swelling that is disproportionate to the knee swelling.
• Numbness, tingling, or weakness in the foot or leg.
• Inability to bear weight if you were previously able to.

Strategies for Managing Swelling

For persistent swelling not associated with serious complications, a multi-faceted approach is most effective:

• Re-emphasize R.I.C.E. Principles:
  • Rest: Avoid activities that exacerbate swelling. Listen to your body and incorporate adequate rest periods.
  • Ice: Apply ice packs (20 minutes on, 20 minutes off) multiple times a day, especially after exercise or periods of activity.
  • Compression: Continue using a compression bandage or sleeve. Ensure it's snug but not too tight to cut off circulation. Your physical therapist can guide you on proper application.
  • Elevation: Elevate your leg above your heart whenever possible, particularly when resting or sleeping.
• Gentle Movement and Therapeutic Exercise: Paradoxically, gentle, controlled movement can help reduce swelling by promoting the muscle pump mechanism and improving circulation.
  • Ankle Pumps: Repeatedly flex and extend your ankles.
  • Quadriceps Sets: Gently contract your thigh muscle, pushing your knee down into the bed or floor.
  • Straight Leg Raises (as advised): Once approved by your therapist, these can help strengthen the quads.
  • Range of Motion Exercises: Perform prescribed knee flexion and extension exercises within your pain-free range.
• Manual Lymphatic Drainage (MLD): A specialized massage technique performed by a trained therapist can help move stagnant lymphatic fluid away from the swollen area.
• Medication Management: Over-the-counter NSAIDs (like ibuprofen, if approved by your doctor) can help reduce inflammation and pain. Your doctor may also prescribe stronger anti-inflammatory medications if necessary.
• Nutrition and Hydration: A balanced diet rich in anti-inflammatory foods (fruits, vegetables, lean proteins) and adequate hydration supports the body's healing processes and fluid balance.

The Road to Recovery: Patience and Persistence

Knee surgery recovery is a marathon, not a sprint. While frustrating, persistent swelling at five weeks is often a sign of ongoing healing and a reminder to respect the recovery timeline. Individual recovery rates vary significantly based on the type of surgery, your overall health, adherence to rehabilitation protocols, and even genetic factors.

Close communication with your surgeon and physical therapist is essential. They can assess your progress, modify your rehabilitation plan, and address any concerns. By diligently following their instructions, being patient with your body, and proactively managing swelling, you can optimize your recovery and achieve the best possible long-term outcomes.

Conclusion

Persistent knee swelling five weeks after surgery is a common challenge that can arise from the normal healing process, overactivity, or less commonly, more serious complications. Understanding the potential causes empowers you to take appropriate action. Prioritizing rest, elevation, ice, and compression, alongside adherence to your prescribed rehabilitation exercises, are key strategies. Always consult your medical team if swelling is severe, worsening, or accompanied by red-flag symptoms, to ensure a safe and effective recovery.