Fibular Head Bursitis: Causes, Symptoms, Diagnosis, and Treatment

What is bursitis of the fibular head?

Bursitis of the fibular head is an inflammatory condition affecting the bursa located near the head of the fibula, a small bone on the outside of the lower leg, typically causing localized pain, tenderness, and swelling at the outer aspect of the knee.

Anatomy of the Fibular Head and Related Structures

To understand bursitis of the fibular head, it's essential to first grasp the relevant anatomy. The fibular head is the enlarged, proximal (upper) end of the fibula, the thinner of the two bones in the lower leg. It articulates with the tibia, forming the superior tibiofibular joint, just below the lateral (outer) side of the knee joint.

Several crucial structures converge around the fibular head:

• Lateral Collateral Ligament (LCL): A strong ligament that connects the femur (thigh bone) to the fibular head, providing stability to the outer knee.
• Biceps Femoris Tendon: The common insertion point for the long and short heads of the biceps femoris muscle, one of the hamstring muscles. This strong tendon attaches to the fibular head.
• Common Peroneal Nerve: A major nerve that branches off the sciatic nerve. It wraps around the neck of the fibula, just below the fibular head, making it vulnerable to compression or irritation in this area.
• Bursa: A bursa is a small, fluid-filled sac lined with a synovial membrane, found in areas where tendons, muscles, or skin rub over bones. Its primary function is to reduce friction and cushion these structures during movement. While the exact bursa involved with "fibular head bursitis" can vary, it typically refers to an adventitious bursa that forms due to friction or, less commonly, the superior tibiofibular joint bursa if one exists.

Understanding Bursitis

Bursitis is the inflammation of a bursa. When a bursa becomes inflamed, the synovial membrane lining it produces excessive fluid, causing the sac to swell and become painful. This swelling puts pressure on surrounding tissues, including tendons, ligaments, and nerves, exacerbating the discomfort.

In the context of the fibular head, bursitis specifically refers to the inflammation of a bursa located in close proximity to the fibular head. This can occur due to repetitive friction from the overlying biceps femoris tendon, direct pressure, or trauma, leading to localized pain and tenderness on the outer side of the knee, just below the joint line.

Causes of Fibular Head Bursitis

Bursitis of the fibular head typically arises from a combination of mechanical stress and, less commonly, systemic factors. Common causes include:

• Repetitive Friction and Overuse:
  • Running and Cycling: Activities that involve repetitive knee flexion and extension can cause the biceps femoris tendon to rub excessively over the fibular head, leading to irritation of the underlying bursa.
  • Prolonged Squatting or Kneeling: Positions that place direct pressure or stretch on the lateral knee can irritate the bursa.
  • Occupational Activities: Jobs requiring frequent squatting, kneeling, or repetitive knee movements.
• Direct Trauma: A direct blow or fall onto the outer aspect of the knee can cause immediate inflammation of the bursa.
• Prolonged Pressure: Leaning against hard surfaces or prolonged pressure on the side of the knee.
• Biomechanical Factors:
  • Tight Hamstrings: Especially a tight biceps femoris muscle, which can increase tension and friction over the fibular head.
  • Gait Abnormalities: Imbalances in walking or running patterns that place undue stress on the lateral knee.
  • Improper Footwear: Shoes that do not provide adequate support or alter biomechanics can contribute.
  • Muscle Imbalances: Weakness in hip abductors or gluteal muscles can lead to compensatory movements that stress the knee.
• Underlying Medical Conditions: While less common for this specific bursa, conditions like rheumatoid arthritis, gout, or infection can predispose individuals to bursitis.

Common Symptoms

The symptoms of fibular head bursitis are generally localized and worsen with specific activities:

• Localized Pain: Typically felt on the outer side of the knee, just below the joint line, directly over the fibular head.
• Tenderness to Touch: The area over the fibular head is often exquisitely tender when pressed.
• Swelling: Visible or palpable swelling may be present over the fibular head, though it can be subtle.
• Pain with Activity: Pain often increases with activities that involve knee flexion and extension, such as running, cycling, squatting, climbing stairs, or prolonged walking.
• Pain with Palpation of the Biceps Femoris Tendon: As the tendon passes over the inflamed bursa, palpating the tendon near its insertion can reproduce pain.
• Warmth: The affected area may feel warm to the touch due to inflammation.
• Limited Range of Motion: In severe cases, pain may limit full knee flexion or extension.
• Nerve Irritation (Less Common but Important): Due to the close proximity of the common peroneal nerve, severe bursal swelling or chronic inflammation can sometimes irritate this nerve, leading to:
  • Numbness or tingling along the outer aspect of the lower leg and top of the foot.
  • Weakness in ankle dorsiflexion (difficulty lifting the foot up), potentially causing "foot drop."

Diagnosis

Diagnosing fibular head bursitis typically involves a thorough clinical evaluation, and sometimes imaging studies.

• Medical History: The doctor will ask about your symptoms, when they started, activities that worsen or improve them, and any history of trauma or underlying medical conditions.
• Physical Examination:
  • Palpation: The most crucial part of the exam involves gently pressing on the fibular head. Localized tenderness and possibly a palpable swelling (fluid sac) over the fibular head are strong indicators.
  • Range of Motion: Assessing knee flexion and extension to check for pain or limitation.
  • Special Tests: Evaluating the integrity of the LCL and assessing for common peroneal nerve function (sensation and motor strength in the lower leg and foot).
  • Gait Analysis: Observing walking or running patterns to identify potential biomechanical contributors.
• Imaging Studies:
  • X-rays: Primarily used to rule out bone fractures, arthritis, or other bony abnormalities, as bursitis itself is not visible on X-rays.
  • Ultrasound: Often the preferred imaging modality as it can clearly visualize soft tissue structures, confirm fluid within the bursa, and assess the degree of inflammation. It can also guide aspiration or injection.
  • MRI (Magnetic Resonance Imaging): Provides detailed images of soft tissues and can definitively confirm bursitis, differentiate it from other conditions (e.g., tendonitis, meniscal tears), and assess for nerve involvement.
• Aspiration: If infection is suspected (e.g., severe redness, warmth, fever), fluid may be drawn from the bursa with a needle (aspiration) and sent for laboratory analysis to check for bacteria or crystals.

Treatment and Management

Treatment for fibular head bursitis typically begins with conservative measures, focusing on reducing inflammation and pain.

• Rest and Activity Modification:
  • Relative Rest: Avoiding activities that aggravate the pain is crucial. This doesn't necessarily mean complete immobilization but rather modifying or temporarily ceasing high-impact or repetitive movements.
  • Activity Modification: Identifying and adjusting the specific movements or postures that trigger symptoms.
• R.I.C.E. Protocol:
  • Rest: As above.
  • Ice: Applying ice packs to the affected area for 15-20 minutes several times a day to reduce inflammation and pain.
  • Compression: Using a compression bandage can help reduce swelling.
  • Elevation: Elevating the leg can further reduce swelling.
• Medications:
  • NSAIDs (Non-Steroidal Anti-Inflammatory Drugs): Over-the-counter options like ibuprofen or naproxen, or prescription-strength NSAIDs, can help reduce pain and inflammation.
• Physical Therapy: A cornerstone of treatment, physical therapy aims to address underlying causes and restore function. This may include:
  • Stretching: Focusing on tight muscles, particularly the hamstrings (biceps femoris) and IT band.
  • Strengthening: Exercises to strengthen the muscles around the knee, hip, and core to improve stability and biomechanics.
  • Modalities: Therapeutic ultrasound, electrical stimulation, or heat/cold therapy may be used to manage pain and inflammation.
  • Gait Analysis and Biomechanical Correction: Identifying and correcting faulty movement patterns, footwear issues, or muscle imbalances.
• Injections:
  • Corticosteroid Injections: A corticosteroid (anti-inflammatory medication) mixed with a local anesthetic can be injected directly into the bursa to quickly reduce inflammation and pain. This is usually considered if conservative measures are not effective.
• Aspiration: If there is significant fluid accumulation, the bursa may be drained (aspirated) to relieve pressure and pain. This is often combined with a corticosteroid injection.
• Surgery (Rare): Surgical removal of the bursa (bursectomy) is rarely necessary and is only considered for chronic, severe cases that do not respond to extensive conservative treatment and injections.

Rehabilitation and Prevention

Once the acute inflammation subsides, a structured rehabilitation program is vital to prevent recurrence.

• Gradual Return to Activity: Slowly reintroduce activities, progressively increasing intensity and duration. Avoid sudden increases in training load.
• Addressing Biomechanical Issues:
  • Footwear: Ensure proper, supportive footwear appropriate for your activity. Orthotics may be recommended for significant foot biomechanical issues.
  • Training Technique: Review and correct running form, cycling setup, or other activity-specific techniques that may contribute to stress on the fibular head.
• Strength and Flexibility Program:
  • Hamstring Flexibility: Regular stretching, particularly for the biceps femoris muscle.
  • IT Band Stretching: To prevent excessive tension on the lateral knee.
  • Hip and Core Strengthening: Building strength in the gluteal muscles (e.g., glute medius) and core can significantly improve lower limb alignment and reduce knee stress.
  • Quadriceps and Calf Strengthening: To ensure balanced muscle development around the knee.
• Warm-up and Cool-down: Always perform a dynamic warm-up before activity and a static cool-down with stretching afterward.
• Progressive Overload: When increasing training volume or intensity, do so gradually (e.g., the 10% rule for runners) to allow the body to adapt.

When to Seek Medical Attention

While many cases of bursitis can resolve with rest and self-care, it's important to seek medical attention if you experience:

• Severe pain that doesn't improve with rest or over-the-counter pain relievers.
• Rapidly worsening swelling, redness, or warmth around the fibular head, especially if accompanied by fever or chills, as these can indicate an infection (septic bursitis).
• Inability to bear weight on the affected leg.
• Symptoms that persist or worsen despite conservative home treatment for several weeks.
• Numbness, tingling, or weakness in the lower leg or foot, which could indicate irritation or compression of the common peroneal nerve.