24 Meniscal Injuries/Repair: RapidLoc
Recently developed meniscal repair devices offer a self-adjusting approach for meniscal repair.1 The RapidLoc is one such device and offers the same advantages of earlier meniscal device designs with the ability to tighten up (or adjust) the repair suture by the use of a sliding knot combined with an absorbable “TopHat.” Although this design leaves a biodegradable piece (poly L-lactide or polydioxanone) within the joint, the ease of insertion and accuracy of this new device are attractive features.
The implant consists of three parts: a soft tissue anchor (“backstop”); a suture (2-0 braided polyester or 2-0 Panacryl); and the TopHat, which when combined with a sliding knot applies compression to the meniscus fragments. The preloaded implant is in a needle. The needle is pushed through the meniscus, and the toggle anchor or backstop is inserted through both parts of the torn meniscus and into the peripheral capsule. The needle is withdrawn, leaving the backstop in the capsule and the suture deployed. This suture connects the backstop to the TopHat. The TopHat with its sliding knot are pushed down the suture to dimple the meniscus surface and compress the inner meniscus fragment against the outer fragment. The knot maintains the compression.
Indications
- Peripheral, longitudinal tears with a good blood supply and no significant secondary tearing. Tears at the synovial meniscal junction may be difficult to repair with this technique because of the lack of peripheral meniscus to anchor the device’s Backstop (red/white region).
- Tear length: usually 1 to 2.5 cm long. This device is best used with posterior third meniscus tears. Tears in the middle third can sometimes be addressed, although reaching more anteriorly is usually not possible because of the angle.
- The all-inside nature of this device makes it especially well suited for tears in the posterior medial or posterior lateral meniscus where inside-out techniques might injure the neurovascular structures.
Contraindications
- Compromised meniscal blood supply
- Degenerative or horizontal tears
- Multiple bucket-handle tears
- Degenerative articular cartilage change
- Allergy to poly-L lactide or polydioxanone
Physical Examination
- Joint line tenderness
- McMurray’s test (or other meniscal tests) positive
- Effusion
Diagnostic Tests
- Physical examination
- Knee radiographs
- Magnetic resonance imaging (MRI) (sometimes indicated)
Special Considerations
At this time, there are no long-term studies that indicate whether this new meniscal repair device is as effective as conventional sutures. Additionally, the postoperative rehabilitation program is a matter of educated opinion rather than objective data. The successful and consistent insertion of this device requires meticulous adherence to the technique and the use of the associated instrumentation. A concern is that the TopHat may separate from the suture at some time in the healing process and migrate within the joint. Adverse events have been reported and include articular cartilage damage2 and the potential for peripheral soft tissue entrapment, including the medial collateral ligament and popliteus tendon.3
Preoperative Planning and Timing of Surgery
- For combined anterior cruciate ligament (ACL) and meniscal tears, it is desirable to wait until the effusion is resolved and good motion established before repairing the meniscus in either a separate staged procedure4 or at the same time as the ACL.
- The exception to this is the displaced bucket-handle (locked) meniscus tear, which may not be repairable in its entirety using the RapidLoc and may require conventional sutures as well (a hybrid repair). For such a locked tear, the immediate repair of the meniscus followed at a later date by ACL reconstruction after knee motion is reestablished will reduce the potential for postoperative stiffness.4
- Early repair of the isolated meniscus tear has not been demonstrated to improve the results, although it is expected that the meniscus to be repaired will sustain less damage the earlier it is addressed.
Special Instruments
- RapidLoc devices are attached to either curved or straight needles.
- RapidLoc disposable insertion gun
- Use of the associated malleable retractor clears away the soft tissue.
- RapidLoc knot pusher
Anesthesia
Options are general anesthesia, regional anesthesia, or local anesthesia.
Patient and Equipment Positions
- Patient is supine with knee in leg holder
- Standard knee arthroscopy setup
- Standard anterolateral, anteromedial, or central arthroscopy portals
- View through the ipsilateral (or central) portal and instrument through the contralateral portal, except for the extreme posterior horn tear in which case the ipsilateral portal may provide more effective access.
- To access the posterior medial meniscus, hold the patient’s knee slightly flexed with valgus stress. Access the posterior lateral meniscus by holding the knee in a figure-four position (~90 degrees) with varus stress.
- The malleable retractor is required to avoid the fat pad during device insertion into the joint.
- Procedures to promote meniscal healing (vascular access channel punch, meniscal rasp, and synovial abrasion) should be used.