What are the management options for a patient with continuous medial knee pain after Anterior Cruciate Ligament (ACL) surgery?

Management of Continuous Medial Knee Pain After ACL Reconstruction

A comprehensive rehabilitation program focusing on closed kinetic chain exercises, neuromuscular training, and targeted pain management should be implemented for patients experiencing continuous medial knee pain after ACL reconstruction.

Evaluation of Medial Knee Pain Post-ACL Reconstruction

When evaluating continuous medial knee pain after ACL reconstruction, consider these potential causes:

• Deep medial collateral ligament (MCL) injury or scarring
• Patellofemoral pain syndrome
• Hardware-related pain (especially with hamstring grafts)
• Inadequate rehabilitation progression
• Neuromuscular imbalances
• Graft-related issues

Evidence-Based Management Approach

1. Rehabilitation Protocol Optimization

• Immediate knee mobilization should be implemented following ACL reconstruction to increase joint range of motion, reduce knee pain, and prevent soft tissue-related adverse events 1
• Strength and neuromuscular training should be initiated early and continued throughout rehabilitation 1
• Closed kinetic chain (CKC) exercises should be prioritized in the first postoperative month to mitigate the risk of patellofemoral pain 1
• Open kinetic chain (OKC) exercises can be added as early as 4 weeks postoperatively in a restricted ROM of 90-45° 1
  • For bone-patellar tendon-bone (BPTB) grafts: Extra resistance is allowed
  • For hamstring grafts: No extra weight should be added in the first 12 weeks to prevent graft elongation

2. Targeted Pain Management

• Cryotherapy can be applied in the first postoperative week to reduce pain 1
• Ultrasound-guided corticosteroid injection into the deep MCL may be considered for patients with persistent medial knee pain with MRI evidence of deep MCL injury 2
• Neuromuscular electrical stimulation (NMES) can be added to isometric strengthening in the initial 6-8 weeks to re-educate voluntary contraction and increase quadriceps strength 1

3. Advanced Rehabilitation Techniques

• Isokinetic rehabilitation has shown significant improvement in knee function and pain reduction for patients with anterior knee pain after ACL reconstruction 3
• Neuromuscular training should be added to strength training to optimize self-reported outcomes and prevent reinjuries 1
• Supervised rehabilitation may be beneficial for some patients, though home-based programs can be effective for highly motivated individuals 1

Duration and Progression

• Rehabilitation should continue for 9-12 months, depending on the patient's return-to-work or play goals 1
• The duration should be individualized based on the patient's ability to safely return to their preinjury activity level 1
• Specific criteria should be used to progress rehabilitation, mindful of minimum time requirements for graft protection and healing 1

Common Pitfalls and Considerations

1. Hardware-related pain is more common with hamstring grafts (13.9%) compared to BPTB grafts (0.8%) 4
2. Anterior knee pain is initially higher in the patellar tendon group but equalizes after 2 years 4
3. Rerupture rates are statistically higher in hamstring grafts compared to BPTB grafts 4
4. Psychological factors such as self-efficacy, locus of control, and fear of reinjury influence the rehabilitation process 1
5. Persistent medial knee pain may be due to deep MCL injury that requires specific treatment beyond standard ACL rehabilitation 2

Algorithm for Managing Persistent Medial Knee Pain

1. First 4-6 weeks post-op with medial pain:

   • Optimize CKC exercises
   • Apply cryotherapy
   • Consider NMES for quadriceps activation
   • Ensure proper gait pattern with immediate weight bearing

2. Persistent medial pain at 6-12 weeks:

   • Obtain MRI to evaluate for deep MCL injury or other pathology
   • If deep MCL injury confirmed, consider ultrasound-guided corticosteroid injection 2
   • Progress to OKC exercises with appropriate ROM restrictions based on graft type
   • Add neuromuscular training

3. Continued medial pain beyond 12 weeks:

   • Implement isokinetic rehabilitation program 3
   • Evaluate for hardware-related pain, especially with hamstring grafts 4
   • Consider periarticular injections targeted toward local neurological structures 5
   • Assess psychological factors that may contribute to pain perception 1

By following this evidence-based approach, most patients with medial knee pain after ACL reconstruction can achieve significant improvement in pain and function, allowing for return to pre-injury activities.