What is the recommended approach for repairing an Anterior Cruciate Ligament (ACL) injury in a patient with fibular hemimelia?

ACL Repair in Fibular Hemimelia: Surgical Approach and Rehabilitation

For patients with fibular hemimelia requiring ACL repair, simultaneous ACL reconstruction with limb lengthening procedures is recommended to provide knee stability and reduce complications during rehabilitation. 1

Understanding Fibular Hemimelia and ACL Deficiency

Fibular hemimelia presents unique challenges for ACL repair due to:

• 95% of patients with fibular hemimelia have congenital absence of the ACL 2
• Associated limb length discrepancy and foot deformities complicate management 3
• Joint stability is critical when treatment includes bony lengthening 1

Surgical Approach

Recommended Surgical Strategy

1. Combined Approach:

   • Perform ACL reconstruction simultaneously with limb lengthening procedures 1
   • This consolidates multiple procedures and improves both limb length symmetry and knee stability

2. ACL Reconstruction Method:

   • Follow standard ACL reconstruction guidelines with modifications for anatomical abnormalities
   • ACL tears should be treated with reconstruction rather than repair due to lower risk of revision surgery 4
   • Consider autograft over allograft, particularly in younger patients 5

3. Addressing Associated Deformities:

   • Classify the fibular hemimelia using Paley classification to guide surgical management 6
   • For foot deformities, consider SHORDT procedure for dynamic valgus or SUPERankle procedure for fixed equinovalgus deformity 3

Rehabilitation Protocol

Based on the AAOS and British Journal of Sports Medicine guidelines, rehabilitation should follow a goal-based progression:

Phase 1: Early Rehabilitation (0-6 weeks)

• Week 1:

  • Immediate weight bearing as tolerated with correct gait pattern 4
  • Begin isometric quadriceps exercises if pain-free 4
  • Cryotherapy to reduce pain in first postoperative week 4

• Weeks 2-4:

  • Initiate closed kinetic chain exercises 4
  • Begin open kinetic chain exercises at week 4 in restricted ROM of 90-45° 4

Phase 2: Progressive Strengthening (6-12 weeks)

• Gradually increase ROM according to this schedule 4, 5:

  • Week 5: 90-30°
  • Week 6: 90-20°
  • Week 7: 90-10°
  • Week 8: Full ROM

• Add neuromuscular training to strength training to optimize outcomes and prevent reinjury 4

Phase 3: Advanced Rehabilitation and Return to Activity (3-9+ months)

• Continue rehabilitation for 9-12 months, depending on return-to-activity goals 4, 5
• Perform functional evaluation including hop tests before return to sport 4
• Aim for Limb Symmetry Index (LSI) >90% for strength and hop tests 4
• For pivoting/contact sports, an LSI of 100% is recommended 4

Special Considerations for Fibular Hemimelia

• Long-term outcomes: Patients with fibular hemimelia and ACL deficiency can achieve good long-term function, with mean Lysholm knee scores of 90.2 reported in long-term studies 2

• Monitoring stability: Regular assessment of knee stability is essential during lengthening procedures 1

• Psychological factors: Evaluate psychological changes during rehabilitation, as factors like self-efficacy and fear of reinjury influence outcomes 4

Potential Complications and Management

• Joint instability: Critical to address before lengthening to prevent complications 1

• Recurrent deformity: Performing first surgery at an earlier age (below 5 years) helps prevent recurrent foot deformities 6

• Functional bracing: Not recommended for routine use after ACL reconstruction as they confer no clinical benefit 4

By following this approach, patients with fibular hemimelia can achieve improved knee stability and function while addressing the associated limb length discrepancy and deformities.