ACL Surgery: Understanding Hardware Sensation, Concerns, and Removal

Can you feel the screws after ACL surgery?

While it is uncommon to distinctly feel the screws used in ACL reconstruction after the initial healing phase, some individuals may experience a subtle awareness or occasional sensation, typically due to their proximity to the skin or specific movements, rather than discomfort.

Understanding ACL Reconstruction and Graft Fixation

Anterior Cruciate Ligament (ACL) reconstruction is a common orthopedic procedure aimed at restoring stability to the knee joint following a rupture. The surgery involves replacing the torn ligament with a graft, typically taken from the patient's own body (autograft) or from a donor (allograft). For this new graft to integrate and heal effectively, it must be securely anchored to the bone tunnels drilled in the femur (thigh bone) and tibia (shin bone). This crucial fixation is most commonly achieved using various types of hardware, including screws, buttons, or staples.

Types of Fixation Devices

The choice of fixation device depends on the surgeon's preference, the type of graft used, and the patient's anatomy. The most common fixation methods involve screws, which can be broadly categorized:

• Bioabsorbable (Bioresorbable) Screws: Made from materials like polylactic acid (PLA) or tricalcium phosphate, these screws are designed to gradually dissolve and be replaced by bone over several months to years. This eliminates the need for potential future removal.
• Metal Screws: Typically made from titanium, these screws are permanent implants. They provide strong, immediate fixation and are inert within the body.

Both types of screws serve the same purpose: to compress the graft tightly into the bone tunnels, facilitating the biological process of "ligamentization" where the graft transforms into a new, functional ligament.

The Sensation of "Feeling" Hardware

For the vast majority of patients, the screws and other fixation devices are placed deep within the bone tunnels and are not noticeably felt once the initial post-operative swelling subsides. The body generally adapts to these internal implants without issue.

However, a small percentage of individuals may report a sensation of "feeling" their hardware. This feeling is rarely described as pain from the screw itself, but rather as:

• A subtle pressure or awareness: Especially when pressing directly over the implant site or during certain movements that put stress on the area.
• A cold sensation: Some patients report a feeling of coldness over the hardware, particularly in colder environments.
• Mild discomfort: In specific positions, such as kneeling or direct impact.

It's important to distinguish between normal, subtle awareness and actual pain or irritation.

Factors Influencing Hardware Sensation

Several factors can contribute to whether a patient feels their ACL fixation hardware:

• Location and Depth: Screws that are placed very close to the superficial bone surface or near prominent bony landmarks (e.g., the tibial tubercle) are more likely to be palpable or felt, especially if they are not fully countersunk into the bone.
• Type of Material: While both types can be felt, metal screws are permanent and may be more likely to cause a long-term sensation for some individuals compared to bioabsorbable screws that eventually resorb.
• Individual Sensitivity: Pain thresholds and nerve sensitivity vary greatly among individuals. Some people are simply more attuned to internal sensations.
• Post-Surgical Swelling and Inflammation: In the immediate post-operative period, swelling around the surgical site can make any internal structure feel more prominent. This typically resolves as healing progresses.
• Activity Level and Pressure: Activities that involve direct pressure on the knee, such as kneeling, or specific movements that cause the skin or soft tissues to rub over the implant, can elicit a sensation.

When Feeling Hardware is a Concern

While a subtle awareness of hardware is often benign, certain symptoms warrant immediate attention from your orthopedic surgeon:

• Persistent Pain or Discomfort: If the sensation progresses beyond a mild awareness to persistent or increasing pain, especially if it doesn't resolve with rest or time.
• Clicking or Catching Sensations: A mechanical feeling or sound that suggests the hardware might be irritating surrounding soft tissues, or potentially loose (though rare).
• Skin Irritation or Redness: If the skin directly over the implant site becomes red, warm, tender, or irritated, it could indicate superficial inflammation or a reaction.
• Signs of Infection: Fever, chills, increasing redness, warmth, swelling, or pus drainage from the incision site are serious signs of infection and require urgent medical evaluation.
• Hardware Migration or Loosening (Rare): Although extremely uncommon, if the hardware were to loosen or migrate, it could cause significant pain, instability, or mechanical symptoms.

What to Do If You Feel Your Screws

If you experience any concerning symptoms related to your ACL fixation hardware, or if the sensation becomes bothersome, it is crucial to:

• Contact Your Orthopedic Surgeon: They are best equipped to evaluate your symptoms, determine the cause, and recommend appropriate management.
• Describe Your Symptoms Accurately: Be specific about the type of sensation, its location, what activities exacerbate it, and how long you've experienced it.
• Avoid Self-Diagnosis: Do not assume the cause of your discomfort. Professional medical advice is essential.

Hardware Removal: Is It Necessary?

In most cases, ACL fixation hardware is left in place permanently (if metal) or allowed to resorb (if bioabsorbable) and does not require removal. Hardware removal is typically considered only if:

• Symptomatic Irritation: The hardware causes persistent pain, skin irritation, bursitis, or mechanical symptoms that significantly impact quality of life and cannot be managed conservatively.
• Infection: In rare cases of deep infection involving the hardware, removal may be necessary to clear the infection.
• Fracture or Migration: Although highly uncommon, if the hardware breaks or moves out of its intended position.

The decision to remove hardware is a surgical one and is made in consultation with your orthopedic surgeon after a thorough evaluation.

The Healing Process and Long-Term Outlook

ACL reconstruction is a major surgery, and the healing process is gradual. While the focus is often on graft healing and rehabilitation, understanding the role and potential sensation of fixation hardware is part of comprehensive patient education. For most, any initial awareness of the screws fades as the knee continues to heal and swellings resolve. Long-term, the goal is a stable, functional knee, and the fixation hardware plays a critical, albeit usually unnoticed, role in achieving that outcome.