CAM Surgery: Understanding Hip Arthroscopy for FAI, Recovery, and Outcomes

What is CAM Surgery?

CAM surgery, more formally known as hip arthroscopy for CAM femoroacetabular impingement (FAI), is a minimally invasive orthopedic procedure designed to reshape the femoral head and neck junction of the hip joint, removing excess bone that causes abnormal contact and damage within the joint.

Understanding CAM Impingement

Femoroacetabular Impingement (FAI) is a condition characterized by abnormal contact between the ball (femoral head) and socket (acetabulum) of the hip joint. This abnormal contact is due to bony irregularities on either or both structures, leading to impingement and potential damage to the articular cartilage and the labrum (a rim of cartilage that deepens the hip socket). FAI is broadly categorized into three types: CAM, Pincer, and Mixed.

CAM Impingement specifically refers to a deformity where there is an extra bone growth (a "bump") on the femoral head or neck, making it less spherical. This non-spherical shape prevents smooth rotation within the acetabulum, especially during movements like hip flexion, adduction, and internal rotation (e.g., squatting, sitting deeply, pivoting).

Mechanism of Impingement: As the hip moves, this CAM bump abuts against the rim of the acetabulum, causing repetitive trauma. Over time, this can lead to:

• Labral tears: Damage to the protective cartilage rim.
• Articular cartilage damage: Wear and tear on the smooth lining of the joint, which can progress to osteoarthritis.
• Pain and stiffness: Symptoms that worsen with activity.

Why is CAM Surgery Performed?

The primary goal of CAM surgery is to alleviate pain, restore normal hip mechanics, and prevent further damage to the joint. It is typically recommended when:

• Conservative management fails: Non-surgical treatments such as physical therapy, activity modification, anti-inflammatory medications, and injections have not provided adequate relief or functional improvement.
• Significant symptoms are present: Persistent hip pain, stiffness, catching, or clicking that impairs daily activities or athletic performance.
• Radiographic evidence of CAM deformity: Imaging (X-rays, MRI) confirms the presence of a significant CAM lesion.
• Prevention of progression: Addressing the mechanical impingement aims to reduce the risk of developing or worsening hip osteoarthritis in the long term.

The Surgical Procedure: Hip Arthroscopy for CAM Deformity

CAM surgery is most commonly performed using hip arthroscopy, a minimally invasive technique. This approach involves:

• Small Incisions: Typically 2-3 small incisions (about 1 cm each) are made around the hip.
• Arthroscope Insertion: A thin tube with a camera (arthroscope) is inserted into the joint, allowing the surgeon to visualize the entire hip joint on a monitor.
• Specialized Instruments: Tiny surgical instruments are then inserted through the other incisions to perform the necessary repairs and reshaping.

The key steps in addressing a CAM deformity include:

• Debridement and Repair: Any damaged labral tissue is either removed (debridement) or repaired, often by reattaching it to the bone using small anchors.
• Osteochondroplasty: This is the core of CAM surgery. The surgeon uses a motorized burr to carefully shave down and reshape the extra bone on the femoral head and neck junction. The goal is to restore a spherical contour to the femoral head, allowing it to move freely within the acetabulum without impingement.
• Addressing Co-occurring Deformities: If a Pincer deformity (excess bone on the acetabular rim) is also present, it is typically addressed during the same procedure by trimming the prominent acetabular rim.

Post-Operative Recovery and Rehabilitation

Recovery from CAM surgery is a multi-phased process that requires significant commitment to a structured rehabilitation program.

• Immediate Post-Operative Period (Weeks 0-2): Focus is on pain management, protecting the repaired tissues, and initiating gentle range of motion. Crutches are often used for partial weight-bearing to protect the joint and allow soft tissue healing.
• Early Rehabilitation (Weeks 2-6): Gradual increase in weight-bearing, introduction of light strengthening exercises for the hip and core, and continued improvement in range of motion.
• Intermediate Rehabilitation (Weeks 6-12): Progression to more challenging strengthening exercises, balance training, and initiation of low-impact cardiovascular activities.
• Advanced Rehabilitation (Weeks 12+): Sport-specific drills, agility training, and progressive return to higher-impact activities.
• Full Return to Activity: This can take anywhere from 6 to 12 months or longer, depending on the individual's progress, the extent of the initial damage, and the demands of their desired activities.

Physical therapy is crucial throughout the recovery process. A skilled therapist guides the patient through specific exercises to restore strength, flexibility, balance, and proprioception (awareness of joint position). Adherence to the prescribed rehabilitation protocol is paramount for optimal outcomes.

Potential Risks and Complications

While hip arthroscopy for CAM FAI is generally safe, as with any surgical procedure, there are potential risks and complications, including:

• General surgical risks: Infection, excessive bleeding, blood clots (deep vein thrombosis).
• Nerve damage: Temporary or, rarely, permanent numbness or weakness due to nerve irritation or injury.
• Heterotopic ossification: Abnormal bone growth in the soft tissues around the hip.
• Persistent pain or stiffness: Despite successful surgery, some patients may experience ongoing symptoms.
• Need for revision surgery: In some cases, symptoms may recur, or new problems may develop, requiring further surgical intervention.
• Failure to prevent arthritis: While the goal is to slow progression, the surgery does not guarantee prevention of osteoarthritis, especially if significant cartilage damage was present pre-operatively.

Outcomes and Long-Term Outlook

The outcomes of CAM surgery are generally favorable, with a high percentage of patients reporting significant reduction in pain and improvement in hip function. Factors that tend to predict better outcomes include:

• Younger age at the time of surgery.
• Less severe pre-existing cartilage damage.
• Adherence to the post-operative rehabilitation program.
• Absence of other significant hip pathologies.

While CAM surgery can effectively address the mechanical impingement and improve quality of life, it is important to understand that it is a reconstructive procedure aimed at restoring normal mechanics and preventing further damage, rather than a cure for all hip problems. Long-term studies continue to evaluate its effectiveness in definitively preventing the progression of hip osteoarthritis.