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Repairs of the Lateral Meniscus

- See: Lateral Meniscus /  General Discussion of Meniscal Repair

- Indications:
     - any peripheral nondegenerative longitudinal tears < 3 cm;
     - if tear is w/in 3 mm of the periphery, it is considered vascular;
     - area 3-5 mm from periphery is grey zone, & > 5 mm from periphery is considered avascular; (see vascularity of the meniscus)
     - unstable tears or tears within vascular zone that are > 7 mm are repairable;
     - mobile, single, vertical, longitudinal tear of the meniscus limited to vascular outer one-third of the meniscal substance;

- Relative Contra-indications:
    - tears greater than 3 cm do not seem to heal, following surgery;
    - transverse tears, even in the periphery, do not seem to heal;
    - do not repair flap tears, radial tears, cleavage tears, or vertical tears with secondary lesions that extend into avascular inner 2/3 of meniscus, except in young teen agers;
    - ligamentous instability is a relative contraindication to repair;
            - w/ ACL insufficiency,  rate or re-tearing approaches 40%, especially in younger acitve individuals, and therefore ACL reconstruction is performed at same surgery;
                   - management of combined meniscal tears and ACL tears;
            - references
                   - Arthroscopic meniscal repair using an exogenous fibrin clot.
                   - Surgical techniques for arthroscopic meniscal repair.  

- Position:
    - knee flexion of 70-90 deg allows peroneal nerve to move posteriorly;

- Incision: (see: lateral compartment of the knee)
    - 5 cm vertical incision centered over posterolateral corner, just posterior to the LCL;
    - peroneal nerve is identified;
    - surgical dissection procedes between the posterior edge of the IT band (retracted anteriorly) and the anteiror border biceps (retracted posteriorly;)
    - further exposure reveals the gastrocnemius which is also retracted posteriorly; (gastroc is identified by flexing and extending the ankle);
    - the interval between the posterolateral capsule and the gastroc is defined;
    - peroneal nerve position:
           - proximally the nerve lies behind the head of the gastrocnemius;
           - distally the nerve lies behind the biceps;
    - knee is flexed to at least 45 deg to allow the peroneal nerve to fall posteriorly;

- Inside-Out Mensical Repair Technique:
    - advantages: this technique allows for precise placement of sutures in the mensicus;
    - disadvantages: this technique does not allow for precise placement of sutures thru the capsule, and therefore there is some potential for neurovascular injury;
    - equipement:
          - single or double barrel cannula system;
          - table spoon or small spade retractor;
          - long keith needles w/ either 2-0 or O absorable or non absorbable;  if absorabable sutures are chosen, use prolene;
    - meniscal debridement:
    - fibrin clot:
          - it was originally recommended that an exogenous blood clot be placed into the meniscal repair site, but this is probably not necessary;
          - Johnson LL (1991) has demonstrated that during and following arthroscopic surgery, blood clot generated during case attaches to surgically
                 incised surfaces (including debrided edges of the meniscal tear);
                 - w/ this evidence, it may not be necessary to apply and exogenous clot, since the majority of blood clot is formed from synovial bleeding;
          - ref: Characteristics of the Immediate Postoperative Blood Clot Formation in the Knee Joint
    - suture passage:
          - w/ the knee in flexion, all needles should pass anterior to the biceps tendon inorder to avoid injury to the peroneal nerve;
          - sutures may pass thru the popliteus w/o complication;
          - consider using the anteromedial portal to pass sutures through the lateral meniscus in a more lateral direction (which will avoid the posterior N/V structures);
          - ref: Anatomic Localization of the Popliteal Artery at the Level of the Knee Joint: a Magnetic Resonance Imaging Study. 

    - suture spacing:
          - enough sutures are placed to avoid gaps of more than 3-5 mm;
          - sutures can be placed in horizontal, oblique, or verticle direction;
          - verticle suture placement may be stronger due to the circumferential orientation of the collagen bundles (see microscopic anatomy);
          - horizontal sutures are almost as strong as verticle sutures, but are more apt to cause eversion of the opposite meniscal surface;
                  - eversion is avoided by placing sutures on both the superior and inferior mensical surface;
                  - always place the anterior suture first, so that the view of the posterior suture is not obstructed;
          - concomitant ACL reconstruction:
          - references:
                  Arthroscopic meniscal repair using an exogenous fibrin clot.
                  Surgical techniques for arthroscopic meniscal repair.  

- Post Op Rehab:
    - Wt bearing as tolerated in brace locked in extension;
    - ROM is allowed when not wt bearing;
    - atheletics are permited in 4-6 months;

- Complications:
    - peroneal nerve injury

Peroneal nerve dysfunction as a complication of lateral meniscal repair: a case report and anatomic dissection.

Meniscal repair. Description of a surgical technique.

Long-term results of open meniscal repair.

Preparation of an exogenous fibrin clot.

Open meniscus repair. Technique and two to nine year results.

Combined posterior incision and arthroscopic intra-articular repair of the meniscus. An examination of factors affecting healing.

The arthroscopic meniscal repair. Techniques and clinical experience

Arthroscopic meniscus repair: a safe approach to the posterior horns.

An organ culture model for assaying wound repair of the fibrocartilaginous knee joint meniscus.

Arthroscopic meniscal repair using an exogenous fibrin clot.

Meniscal repair using an exogenous fibrin clot. An experimental study in dogs.

Failure strengths of different meniscal suturing techniques.

Second look arthroscopy after meniscal repair. Factors affecting the healing rate.

Complications in arthroscopy: the knee and other joints. Committee on Complications of the Arthroscopy Association of North America.