Reaching the six-month mark after an anterior cruciate ligament (ACL) reconstruction is a milestone in your recovery. While it is a time to begin returning to more normal activities, it is also common to experience some knee pain. This can be a source of frustration and concern. Understanding what is typical at this stage is part of the process of managing your symptoms and continuing your recovery.
The Six-Month Recovery Milestone
Six months post-surgery, specific rehabilitation goals provide a benchmark for your progress. Your physical therapist has likely worked with you to achieve a full range of motion, allowing you to straighten and bend your knee to match your uninjured leg. Strength is another focus, with the goal being that your quadriceps and hamstring muscles have regained much of their original power. Functional tests may show you can perform activities like jogging, single-leg balancing, and light agility drills.
While these milestones are standard, recovery is individual. The type of graft used for the reconstruction can influence healing and sensation around the knee. Swelling, while reduced from the initial weeks, might still occur intermittently after strenuous activity. It is normal for your knee not to feel exactly as it did before the injury, as some awareness or minor discomfort can persist.
The objective at six months is to have a stable knee that supports more demanding activities. This stability, combined with improving strength and motion, forms the foundation for the next phase of rehabilitation. This phase involves more sport-specific movements and a gradual return to play. Comparing your progress to these targets helps you and your physical therapist identify areas needing more attention.
Common Causes of Persistent Knee Pain
Persistent pain at the six-month point can be traced to how your body adapts to increased physical demands. Pushing too hard or too soon is a frequent cause of overuse conditions. One problem is patellar tendonitis, an inflammation of the tendon connecting your kneecap to your shinbone, aggravated by repetitive jumping or running. Fat pad impingement also occurs when the fatty tissue below the kneecap becomes pinched, causing sharp pain at the front of the knee.
Muscle imbalances are another contributor to discomfort. After surgery, it is common for the quadriceps muscles to be weaker than the hamstrings. This imbalance can alter how the kneecap moves, leading to patellofemoral pain syndrome. This presents as a dull, aching pain around or behind the kneecap that worsens with activities like squatting or climbing stairs. Weakness in the glutes and hips can also contribute by allowing the knee to drift inward, placing stress on the joint.
Factors from the surgery itself can be a source of ongoing pain. The hardware used to secure the new ligament, such as screws or buttons, can cause irritation to surrounding tissues. Another possibility is the development of excessive scar tissue inside the joint, a condition called arthrofibrosis. This leads to stiffness, reduced range of motion, and pain. Pain may also originate from the site where the graft was harvested.
Pain may also stem from underlying issues present at the time of the original injury. Damage to the cartilage or meniscus that occurred with the ACL tear might continue to cause symptoms. While less common, problems with the healing or integration of the graft itself can be a source of pain. This may be accompanied by a feeling of instability in the knee, which suggests a problem needing further evaluation.
Managing Pain and Aiding Recovery
Managing knee pain at this stage requires working with your physical therapist. Communicate the specific location, type, and intensity of your pain so they can adjust your rehabilitation program. The focus is on modifying your routine to allow irritated tissues to heal while you still make progress. This might involve reducing high-impact activities like running in favor of lower-impact options like cycling or swimming.
Your therapist may also refine your exercise technique. Improper form during squats or lunges can place stress on the knee joint, and correcting these patterns can alleviate pain. They may introduce new exercises to strengthen supporting muscle groups like the hips, glutes, and core. Strengthening these areas improves your leg’s alignment and controls the forces acting on the knee.
Adequate rest and recovery are as important as the exercises. Your body needs time to adapt and repair tissues between sessions. Your physical therapist can help you balance building strength with allowing for rest. Techniques like icing the knee after a workout can manage inflammation, while stretching tight muscles can improve flexibility and reduce strain.
When to Consult Your Surgeon
While many aches are part of rehabilitation, certain “red flag” symptoms require a consultation with your surgeon. These signs may indicate a problem that needs medical evaluation to rule out serious complications and keep your recovery on track. Contact your surgeon if you experience any of the following:
- Mechanical symptoms, such as your knee locking, catching, or giving way.
- A persistent increase in swelling that does not resolve with rest and ice.
- Pain severe enough to consistently wake you from sleep.
- An inability to bear weight on your leg after you have been cleared to do so.
- A noticeable loss of motion you had previously gained, such as being unable to fully straighten your knee.