Dealing with Knee Pain After ACL Reconstruction Surgery

Anterior cruciate ligament (ACL) tears are a common knee injury, especially among athletes. Approximately 200,000 ACL reconstruction surgeries are performed in the United States every year to repair these torn ligaments. While the procedure helps stabilize the knee long-term, post-operative knee pain is incredibly common.

In one study, as many as 72% of patients continued experiencing knee pain even 2 years after their ACL reconstruction. This pain can persist due to multiple biomechanical and inflammatory factors during the healing and rehab process.

Understanding typical recovery timelines and implementing self-care and physical therapy protocols appropriately can help manage discomfort. With proper treatment, most individuals experience significant improvements in knee pain and function over the first post-operative year.

Acute Knee Pain: Swelling and Inflammation

In the early phases after surgery (1-2 months), acute inflammation around the knee joint is very common. Triggered by surgical trauma, swelling, stiffness, and significant pain with movement often occur as part of the body’s healing response. Fluid buildup and inflammation in and around the joint can lead to throbbing discomfort and difficulty bearing weight through the leg.

Controlling Inflammation Initially Critical

During this inflammatory period, management involves medication, frequent icing, compression bandages, keeping the leg properly elevated, and joint offloading with crutches or a brace. Moving too aggressively through range of motion before inflammation settles can worsen fluid build-up. Finding the right balance between rest and gentle movement is key. Once swelling reduces, light physical therapy emphasizing controlled mobility and muscular activation begins.

Ongoing Knee Pain Risk Factors

While most patients move past the intense acute pain phase after about 6-8 weeks, some individuals continue battling discomfort even months or years later. There are several potential culprits of this lingering knee pain:

Improper Biomechanics: Imbalances or atypical movement patterns (known as compensations) during activities like walking, running or squatting after ACL surgery can overload areas around the knee joint. Common issues involve knocking knees inward, improper landing mechanics from jumping, overpronating feet, and relying too heavily on uninjured limbs during exercise. Certain patients are predisposed towards persistent abnormalities or asymmetries due to age, sex, genetics and pre-existing conditions.

Quadriceps Weakness: The thigh muscles (quadriceps) typically atrophy after ACL tears from disuse and inflammation. Reactivating and rebuilding quadriceps strength is paramount for stabilizing the knee for dynamic activities. However, lingering weakness is common long-term after ACL reconstruction. This affects range of motion and shock absorption, causing worse outcomes and pain.

Secondary Joint Injuries: After ACL surgery, patients often unconsciously overcompensate and overload adjacent joints like the hip and ankle while recovering. Cartilage wear, tendinitis and premature arthritis in these areas causing referred pain at the knee is increasingly recognized. Similarly, other structures like the meniscus are frequently damaged in combination with ACL tears, necessitating additional surgeries if problematic.

Scar Tissue Build-Up: During healing, dense scar tissue commonly develops around the ACL graft. In some people, too much builds up or it adheres incorrectly to surrounding tissues. This misplaced and inflexible scar tissue tugging on nerves can directly generate knee pain with movement.

Graft Complications: In rarer cases of chronic pain, issues with the ACL graft itself have occurred. This includes delayed healing, improper graft positioning during surgery, reinjury of the graft, and possibly graft-tunnel mismatches contributing to instability and pain.

What Does Rehab Program Include?

Custom structured physical therapy programs are essential not only for regaining knee functionality after ACL reconstruction, but also helping wean off pain medications and prevent future problems.

Stage 1 – Early Mobility & Range of Motion

Begins with 1-2 weeks of inflammation control, then progresses to restoring passive knee extension/flexion mobility (ideally full range of motion by 12 weeks). Light quadriceps activation and proprioception exercises follow.

Stage 2 – Muscle Strengthening Phase

Focuses primarily on rebuilding quadriceps and hip strength, while progressing standing balance challenges. Abandoning crutches and slowly reintegrating walking with good mechanics is targeted before more advanced drills.

Stage 3 – Multiplane Dynamic Control

Incorporates movement pattern and stability training including single leg loading, squats, agility movements in multiple planes of motion. The goal is reestablishing proper knee shock absorption strategies and lower limb control. Closely managing strength/activity progressions prevents overloading.

Stage 4 – Sports Specific Training

Transitions towards advanced plyometric and high intensity sport-specific conditioning to simulate demands of athletic participation. Confidence in knee function gets tested before gradual full competition clearance.

Adhering to activity restrictions and exercise protocols in each phase allows for appropriate muscular and tissue-loading to stimulate healing without provocation. Touching base regularly with physical therapists and surgeons ensures appropriate customization and progressions.

Treatment Options for Ongoing Pain

If knee pain persists months beyond surgery despite appropriate adherence to rehabilitation protocols, further targeted evaluation and management is warranted:

• Imaging Tests like x-rays, CT or MRI scans help identify abnormal bony alignment or positioned grafts contributing to symptoms. Secondary injuries causing issues are also spotted.
• Return to the OR – Occasionally revision ACL surgery is required if the graft re-tears or was improperly placed. Other joint debris clean-ups or repairs (like meniscus fixing) may help reduce pain generators.
• Viscosupplementation Injections – Hyaluronic acid gel injections into the knee can help lubricate and cushion joint spaces, temporarily aiding pain.
• Braces & Orthotics – Unloader knee braces and custom shoe inserts help take pressure off injured ACL graft or problem joint areas to alleviate discomfort.
• Physiotherapy – Further advanced manual therapy, taping techniques and corrective exercises target the specific dysfunction (quad weakness, movement pattern abnormalities etc) perpetuating pain.

While most post-ACL reconstruction knee pain improves significantly in 6-12 months with concerted rehabilitation, lingering issues left unaddressed can remain problematic long-term and increase arthritis risk. Thus, prompt intervention tailored to root causes provides better function restoration and enhanced quality of life.

Moving Forward Post-Surgery

Though uncomfortable and frustrating, pain after ACL surgery remains fairly common with modern techniques. Sticking firmly to prescribed activity guidelines and customized therapy plans allows for appropriate muscular development and movement pattern retraining for long-term knee health.

Patience and perseverance are key – with concerted effort from both patient and medical team, the road to recovery continues getting smoother. If pain seems atypical or severe, do not hesitate reaching out promptly to treat any complications early before they become permanent. With today’s treatment algorithms prioritizing function preservation, a return to high performance athletics and an active lifestyle is very achievable after ACL tears.