What happens with sutures in meniscus repairs?

Suture Behavior in Meniscal Repairs

In meniscal repairs, sutures initially provide structural support but may create gaps between meniscal margins within the first loading cycles, with vertical sutures showing superior resistance to tissue failure compared to horizontal sutures. 1

Types of Sutures Used in Meniscal Repair

• Vertical mattress sutures demonstrate 100% suture failure mode (rather than tissue failure), indicating better tissue preservation and superior resistance compared to horizontal sutures 1
• Horizontal mattress sutures show 50% suture failure and 50% tissue failure, with broader gaps appearing during cyclic loading 1
• Permanent (non-absorbable) sutures are associated with lower failure rates and fewer clinical symptoms compared to absorbable sutures in meniscal repairs 2
• Both monofilament (PDS) and braided (Ethibond) suture materials show similar biomechanical properties under standard loading conditions 1

Biomechanical Behavior of Sutures

• During initial loading cycles, suture threads may cut through meniscal tissue and partially disappear from the surface, particularly with horizontal sutures 1
• Gaps appear between meniscal margins within the first loading cycles regardless of suture type or material 1
• Under cyclic loading conditions (simulating normal knee movement), approximately 13% of meniscal sutures may fail 1
• The ultimate failure load of meniscal sutures after cyclic loading remains similar to those without cyclic loading (approximately 60N) 1

Clinical Implications

• Meniscal repairs have better long-term patient-reported outcomes, better activity levels, and lower failure rates compared to meniscectomy 3
• Continuous suturing techniques distribute tension more evenly across the repair, potentially reducing the risk of tissue edema and necrosis 3
• Meniscal repairs preserve the important functions of the meniscus including load distribution, joint lubrication, stability, and proprioception 4, 5
• Arthroscopic meniscal repair techniques have evolved to allow for effective repair of various tear patterns, including radial tears that were previously treated with meniscectomy 5

Suture Placement Considerations

• Vertical suture placement is recommended when possible due to superior resistance to tissue failure 1, 6
• Sutures should be positioned tightly together to ensure proper healing 6
• Positioning sutures that perforate the meniscus vertically usually leads to more stable healing 6
• Tears in the peripheral, vascularized zone (red-red or red-white zone) have better healing potential due to blood supply 6, 2

Potential Complications

• Suture failure may occur under repetitive loading conditions, even with proper technique 1
• Gap formation between meniscal margins is common within the first loading cycles 1
• Horizontal sutures are more prone to tissue failure than vertical sutures 1
• Absorbable sutures have higher failure rates (18% in one study) compared to permanent sutures (0% failure in the same study) 2

Meniscal repair techniques continue to evolve, with newer continuous suture methods being developed for various tear patterns, including radial tears that were previously considered irreparable 5. The preservation of meniscal tissue through repair rather than resection is crucial for preventing early knee osteoarthritis and maintaining normal knee biomechanics 4, 5.