RAMP Lesion of the Knee

Courtesy: Herve Ouanezar MD

Topic: Ramp Lesion Repair During ACL Reconstruction

Isolated ACL injuries: Only 25% of cases.
Combined Lesions: Present in 75% of ACL cases.
Three Main Combined Lesions:
- Medial meniscus ramp lesion
- Lateral meniscus root tear
- Anterolateral ligament/complex injury
Definition of Ramp Lesion:
- Disruption of the peripheral meniscocapsular attachment of the posterior horn of the medial meniscus.
- Detection:
  - Often missed when probing from the front.
  - Requires a posterior approach with an arthroscope.
Historical Development:
- First described by Gillquist (1983).
- Craig Morgan (1991) introduced all-inside meniscus repair with hook sutures.
- Recent studies from Korea focus on clinical outcomes of this repair technique.

Caused by:
- Anterior-posterior translation of the tibia.
- Internal rotation of the knee.
- Shear forces from semimembranosus contraction.
Impact on Stability:
- Medial meniscus acts as a secondary stabilizer.
- Ramp lesions contribute to posterior instability.

Prevalence:
- Initial studies (2014): Found only 4-5% incidence.
- Advancements in technique (2020): Found up to 20% incidence.
- Large-Scale Studies:
  - Santi Group (3,214 patients) found 24% prevalence in primary ACL cases.
  - Revision ACL cases: 40% prevalence.
Key Takeaway: If the surgeon does not detect a ramp lesion, the lesion will eventually reveal itself through complications.

MRI Indicators:
- Bone bruise on the posterior medial tibial plateau.
- Often missed on MRI, so direct arthroscopic examination is necessary.
Systematic Arthroscopic Diagnosis (French Arthroscopic Society, 2014):
- Probe the meniscus from the front.
- Push the arthroscope to the posterior medial corner.
- Open the thin layer to check for hidden lesions.

Chinese Study: Suggests some stable lesions may heal spontaneously with simple debridement.
French Study (8-Year Follow-Up):
- Findings:
  - 33% of untreated ramp lesions resulted in complications.
  - Often led to large bucket-handle tears.
- Conclusion: Ramp lesions should be repaired to prevent long-term issues.

Step-by-Step Approach:
- Probe the meniscus.
- Identify the lesion through posterior medial arthroscopy.
- Use transillumination for safe incision (avoiding the saphenous nerve).
- Refresh the tear edges with a shaver.
- Internal rotation of the tibia helps expose the tear for repair.
Preferred Repair Method:
- Use all-inside hook sutures for precise reattachment.
- Non-absorbable sutures (PDS0) to prevent suture-related complications.
- Multiple stitches improve stability (typically 2-3 per tear).
Why Not Use Suture Anchors or Fast-Fix Devices?
- Higher risk of floating anchors (13% incidence).
- Difficulty in closing the lesion properly.
- Increased risk of failure when knee moves into extension.

Briotet Study (Lyon Group):
- All-inside suture anchors had a 31% failure rate.
- Hook suture technique reduced failure rate to 16%.
Santi Group (3,214 patients):
- All-inside anchors: ~25-30% failure rate.
- Hook sutures: Lower failure rate (15% for isolated ACL, 6.6% if combined with ALL reconstruction).

Common Complications (1.5% cases):
- Hematoma.
- Saphenous nerve hypoesthesia.
Prevention Strategies:
- Use transillumination before making the incision.
- Turn off room lights to clearly visualize nerve and vessels.

High Incidence of Ramp Lesions:
- 24% in primary ACL injuries.
- 39% in revision ACL cases.
Systematic Arthroscopic Approach is Essential.
Biomechanical Importance:
- Repairing ramp lesions restores rotational stability.
- Reduces anterior tibial translation.
Best Surgical Practice:
- Use hook sutures for better outcomes.
- Combined reconstruction (e.g., ALL repair) further lowers failure rates.