Meniscal Root Tears: Evaluation, Imaging, and Repair Techniques

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1 Meniscal Root Tears: Evaluation, Imaging, and Repair Techniques R O B E R T N A S C I M E N TO, M D, M S C H I E F OF S P O RT S M E D I C I N E & SH O U L D E R S U R G E RY N E W TO N- W E L L E S L E Y H O S P I TA L M E D I C A L D I R EC TO R & HE A D T E A M P H Y S I C I A N, B O S TO N C O L L E G E AT H L E T I C S

2 Disclosures Depuy Mitek Sports Medicine Speaker / Education Smith & Nephew - Consultant

3 Menisci Semilunar-shaped fibrocartilagenous structures are essential for joint preservation and provide Tibiofemoral joint congruity Stabilization Shock absorption Possibly proprioception Incidence of Meniscal tear 61 / 100,000

4 Vascular supply Arnoczky & Warren (1982) demonstrated the blood supply to the meniscus in the peripheral zone

5 Total Menisectomy Multiple studies have shown increased contact pressures and decreased contact area in the medial compartment after total meniscectomy Leads to the development of radiographic osteoarthritis, often rapidly

6 Partial Meniscectomy Still a lot to be answered regarding Rate of radiologic signs of OA Clinical correlation to these changes Biomechanical studies (Burke 1978, Inh 1993) have found a linear relationship between amount of meniscus removed and increased peak joint stress

7 Approximately 50-70% of all weight transmitted to the medial or lateral knee compartment is transmitted by each individual meniscus Therefore, meniscus integrity is essential for long term health of articular cartilage Posterior horn tears consistently fair much worse with both radiographic findings and clinical outcome

8 Any insult that decreases these dissipated forces, ie meniscectomy, can lead to articular cartilage breakdown Hoser et al (2001) highlighted this by stating many arthroscopic partial meniscectomies may functionally represent total meniscectomy Preservation of the hoop stress is critical

9 Posterior Root Tear: Diagnosis High Suspicion in patients with posterior knee pain Effusion +/- Painful flexion Joint line pain Often inciting event Varus stress in full knee extension may incite palpable medial meniscal extrusion

10 Posterior root tears Highly alter joint biomechanics and kinematics, thus leading to accelerated joint destruction In 1991 Pagnani described a 20 yo football player who developed rapid degeneration of articular cartilage after a posterior root tear More common than previously thought with incidence of ~10% of all tears 10-21% of all meniscus repairs or menisectomies

11 Harner et al., JBJS 2008 Posterior root tear of medial meniscus caused 25% increase in contact pressures

12 Harner et al., JBJS 2008 Posterior root tear acts like total meniscectomy Posterior root REPAIR restored joint mechanics and contact pressures to the normal state

13 Medial Meniscal Root Tears Reported from 3% up to 21% in the literature in differing series Associations with MCL injuries and multi-ligament knee injury Increasing age Female sex Higher BMI

14 Lateral Meniscal Root tears 8-10% of ACL tears Only 1% without ACL tear Sports activities involved in 87% of lateral meniscal root injuries 70% via pivoting mechanism

15 Imaging: Standard Radiographs Weight bearing to access joint space narrowing Consider long leg alignment films MRI Has changed the ability to detect root tears 73% sensitive in one study With meniscus sequences up to 93% sensitive

16 MRI Axial images: Occasionally can get a perfect intesection Not as useful as other sequences Coronal images: Carefully examine the anterior and posterior horns Can see bony avulsions with bone marrow edema Typically cannot follow meniscus into attachment sight Normal Root Tear

17 MRI Coronal Coronal images can also show meniscal extrusion (mid coronal images) Up to 3mm extrusion can be considered normal >3mm does not define a tear but suggests potential injury Can also be associated with arthritis

18 MRI Saggital Easiest sequence to detect a root tear Look for the Ghost sign

19 Classification

20 Posterior Meniscal Root Repair Simple instruments But difficult to gain access to repair site Suture configuration May further complicate the procedure Results Promising in terms of outcome measures and halting radiographic signs of OA

21 Repair Type Typical repair strategies are via a suture anchor repair or pull out suture repair with a transosseous tunnel No repair method has yet been shown to be superior

22 Suture Anchor Repair High posterior medial portal 4cm proximal to the joint and behind condyle Root

23 Transosseous Repair ACL Tibial guide **Specialized targeting guides** Retro ACL reamers Single tunnel Double tunnel

24 Suture configuration Anz et al, AJSM 2014 showed the two double locking suture technique has the highest mean max failure load 2 Simple N Mattress N 1 Double Locking suture N 2 Double Locking suture N

25 Suture Configuration 2 sutures is better than 1 All techniques do not fully restore native strength - > conservative post-op course AVERAGE FAILURE LOAD OF NAITIVE MENSICUS ROOT IS N

26 AJSM 2018 Porcine model 2mm Tape stronger than No. 2 suture (mean failure load 87N vs 56N) Location matters Sutures placed in the body mean failure much greater than those in the root ligament (104N vs 35N)

27 Meniscal Suture Passing Shuttling device Self retrieving suture passer Extra long spinal needle or curved needle

28 Root Attachments Medial meniscal root area ~ 30mm 2 Lateral meniscal root area ~ 39.2mm 2 Johannsen et al, AJSM 2012

29 AJSM 2015 AJSM 2014 Measuring the effect of 1 vs 2 tunnels in repair 2 tunnels might No significant difference in displacement be better than between 1 the two groups: 1 tunnel = 3.32, 2 tunnel= tunnel had 10% higher ultimate failure load but this was not significant Measured displacement at the suture meniscus interface, suture Failure within the tunnel, occurs and button at bone interface Most notable displacement the occurred meniscus at the suture interface and not with the suture suture elongation in junction the tunnel Total displacement was 3.28mm 2.52mm from suture meniscus.71mm from suture elongation.90mm from button bone

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32 Results Medial meniscal root repairs have shown up to 93% rate of partial or complete healing Clinical outcomes are significantly improved with repair across multiple studies LaPrade et al. AJSM 2014 Meniscal Extrusion Ghost Sign

33 Meniscal Root Repair PROS Maintain hoop strains Preserve articular cartilage by dispersing contact pressures Minimize ACL graft stress by stabilizing the knee CONS Time, time, time Money, money, money Technically challenging Failure rates??

34 Meniscus repair and especially posterior root repair will restore normal joint function Optimal suture configuration and techniques are evolving Would you feel comfortable with a total meniscecomy on a patient with Grade I/II arthrosis? Take your time and... Save the knee!!

35 Thank you