Book a free consultation today
Pain area
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.

How to Overcome Knee Instability After ACL Surgery

Knee Instability After ACL Surgery

For athletes and active individuals, an ACL tear can be a devastating blow. While ACL reconstruction surgery offers hope, the road to recovery isn't always smooth sailing.One common hurdle? Persistent knee instability, a frustrating sensation that can derail your progress and leave you questioning your return to normalcy. 

This guide delves into the causes, symptoms, assessment, and rehabilitation strategies to help you regain stability and confidence in your knee.

Intro to ACL Tears

The anterior cruciate ligament (ACL) is a cruciate ligament that stabilises the knee joint, preventing excessive forward movement of the shinbone. An ACL tear can cause instability, pain, and hinder everyday activities.

Why is ACL Reconstruction Surgery Done?

ACL reconstruction surgery repairs the torn ligament using a graft, restoring stability and improving knee function. This helps address issues like:

  • Functional limitations: Difficulty walking, running, or participating in sports.
  • Reduced mobility: Stiffness and pain restricting movement.
  • Muscle weakness and imbalance: Leading to further instability.
  • Fear of reinjury: Anxiety about future knee problems.
  • Associated injuries: Addressing meniscus tears or MCL sprains.

Why Your Knee Might Still Feel Unstable after ACL Surgery: 

Several factors can contribute to post-surgical instability:

  • Incomplete healing: The graft needs time to integrate with surrounding tissues. Incomplete healing can lead to graft laxity and instability.
  • Meniscus tears or other injuries: Damage to other structures like the meniscus can further compromise joint stability.
  • Muscle weakness and imbalance: Strong muscles support the joint and compensate for ligament deficiencies. Weakness can contribute to instability.
  • Poor proprioception: After surgery, your body needs to relearn joint awareness for optimal stability.
  • Technical factors: Surgical technique and graft choice can influence stability outcomes.

Assessing Knee Instability:

Your doctor will use a combination of approaches to identify the cause of your instability:

  • Physical examination: Tests like the Lachman and pivot shift test assess joint laxity.
  • Imaging studies: MRI scans can reveal graft integrity and other internal injuries.
  • Biomechanical analysis: Specialised tests may assess muscle function and movement patterns.

Rehabilitation After ACL Surgery:

Rehabilitation is crucial for regaining stability and function after an ACL Reconstruction. It's typically divided into 4  phases:

Phase 1: Early Postoperative (Weeks 0-2)

  • Pain Management: Tackle pain and swelling with prescribed meds, ice, compression, and elevating your leg.
  • Range of Motion Exercises: Start slow and gentle knee movements to avoid stiffness.
  • Weight-Bearing: Use crutches gradually as your surgeon recommends.
  • Muscle Activation: Begin simple exercises to wake up your quadriceps and hamstrings.
  • Patellar Mobility: Get your kneecap moving smoothly with gentle mobilizations.

Phase 2: Intermediate Strengthening (Weeks 2-12)

 Weeks 2-6:
  • Progressive Range of Motion: Gradually increase your knee's range of motion.
  • Strength Training: Build muscle strength with isometric and closed-chain exercises, focusing on quads, hamstrings, and calves.
  • Balance & Proprioception: Train your body to "feel" your knee better with balance and proprioception exercises.
  • Cardio: Get your heart pumping with low-impact exercises like stationary biking or swimming.
  • Gait Training: Walk normally again, ditching the crutches as you progress.

Weeks 6-12:
  • Dynamic Stability Exercises: Introduce dynamic exercises like single-leg drills and perturbation training.
  • Functional Exercises: Practice movements you need for daily activities and your specific sport.
  • Agility Training: Improve coordination and control with agility drills.
  • Cardio Endurance: Up the intensity and duration of your cardio workouts.
  • Sport-Specific Training: Mimic your sport's movements with tailored rehab exercises.

Phase 3: Return to Restricted Sport-Specific Drills (Months 3-6)

  • Sport-Specific Drills: Practice drills that mimic your chosen sport's demands.
  • Plyometrics: Gradually add plyometric exercises to build power.
  • Running Program: Follow a structured program to regain speed and endurance.

Phase 4: Return to Sports (Months 6-12)

  • Progressive Return: Slowly transition back to your sport.
  • Continued Strength Training: Maintain strong muscles for balance and stability.
  • Regular Monitoring: Get regular assessments to ensure you're ready for full return to sport.

Preventive Strategies and Maintenance:

ACL injuries have a higher risk of reinjury, making preventive measures crucial. Common preventative measures to prevent ACL reinjury: 

●  Neuromuscular Training: Implement neuromuscular training programs to reduce the risk of future   injuries.

●  Strength Maintenance: Continue strength training to maintain muscle balance around the knee.

●  Regular Monitoring: Periodic check-ups with healthcare professionals for ongoing evaluation and guidance.


Dealing with knee instability after ACL surgery can feel overwhelming, especially for those who love sports and staying active. Understanding the reasons behind this instability is important for a good recovery. By following a personalised rehab plan that includes managing pain, strengthening muscles, improving balance, and doing exercises specific to their sport, you can feel more confident in your knee's strength. Working closely with healthcare experts and sticking to the rehab plan helps you get back to your favourite activities feeling strong and confident.