Meniscal Injuries/Repair: FasT-Fix

25 Meniscal Injuries/Repair: FasT-Fix

F. Alan Barber

The FasT-Fix is one of the new self-adjusting meniscal repair devices.^1,2 It is based on the older T-Fix and represents a significant design advance. The FasT-Fix offers the same advantages of the earlier device design, allowing for an all-inside meniscal repair plus a slipknot that can be tightened after the device’s two anchors are inserted through the meniscus. When deployed, this design leaves two 5-mm polyacetyl (plastic) nonabsorbable bars embedded in the peripheral capsule and a knot of No. 0 braided polyester suture tied on the meniscus surface. The device can be deployed so that the suture has either a vertical or horizontal orientation.

Indications

Peripheral, longitudinal tears with a good blood supply and no significant secondary tearing. Sufficient peripheral meniscal material must be present for the polyacetyl anchors to engage and hold. As a result, tears at the synovial meniscal junction (red/white region) may be difficult to repair.
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 the more anterior tears 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 corner 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

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

Several preliminary reports emphasize that there is a significant learning curve to master with this device, and practice prior to its clinical application is essential. Issues include problems with suture tensioning, premature deployment of the first or second toggle anchor, difficulty in advancing the trigger for deployment of the second anchor, and difficulty placing a vertical oriented suture.^3,4 Although no long-term studies are available to support the efficacy of this meniscal repair device, prior studies of the T-Fix provide reassurance of its likely effectiveness and lack of adverse reactions.^5–7

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 procedure⁸ or at the same time as the ACL reconstruction.
An exception is the displaced (locked) bucket-handle meniscus tear, which may require immediate meniscus repair followed by ACL reconstruction at a later date after the knee motion is reestablished to avoid postoperative stiffness. Additionally, such an extensive meniscus tear may not be completely repairable using devices because of limited access to the anterior horn. Such a locked tear may require combination with conventional sutures as well (a hybrid repair).
Early meniscal repair has not been demonstrated to improve the long-term healing results, although it is expected that the meniscus to be repaired will sustain less damage the earlier it is addressed.

Special Instruments

FasT-Fix devices are provided in either curved or straight 17-gauge needles.
FasT-Fix split plastic cannula
FasT-Fix knot pusher, graduated depth sleeve, and suture threader

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 split plastic cannula is required during device insertion to avoid the fat pad.
Procedures to promote meniscal healing (vascular access channel punch, meniscal rasp, and synovial abrasion) should be used.

Surgical Procedure

Establish standard viewing portals. View through the ipsilateral (or central) portal and instrument through the contralateral portal.

Define the tear and encourage a healing response by rasping, creating vascular access channels, and synovial abrasion.

Measure the depth of the tear and cut the white graduated depth sleeve to length. This is placed over the needle to create a penetration safety stop.

Select the appropriate angle of the preloaded needle (straight or curved).

Insert the needle through the appropriate portal, using the split plastic cannula to keep it from becoming fouled in the soft tissue.

Withdraw the split plastic cannula as much as needed or completely remove it.

Reduce the meniscus tear with the needle and pass the needle through both parts of the meniscus and into the joint capsule (Fig. 25–1).
Withdraw the needle from the meniscus with a slight oscillating motion to release the first suture bar into the capsule and soft tissue behind the meniscus (Fig. 25–2).
Tug on the suture gently to test the fixation of this implant.
Slide the gold trigger forward on the handle to advance the second anchor to the fully seated line at the distal needle tip (Fig. 25–3). Failure to do so will make deployment of the second anchor more inconsistent (Fig. 25–4).
Reposition the needle 5 mm away from the fist (horizontally or vertically) and insert it through the torn meniscal tissue again (Fig. 25–5).
Withdraw the needle from the meniscus with a slight oscillating motion to release the second suture bar into the capsule and soft tissue behind the meniscus.
Pull the free end of the suture firmly to remove any slack and partially snug down the repair (Fig. 25–6), then advance the single-lumen knot pusher to tighten the repair completely (Fig. 25–7).
Cut the suture (Fig. 25–8) and deploy additional devices until the repair is complete.

Dressings, Braces, Splints, and Casts

A simple absorptive sterile dressing is applied to the skin.
Compression with Ace bandage
Progressive weight bearing with crutches as needed

Tips and Pitfalls

The straight needle is better for a posterior third tear.
The FasT-Fix must be placed using the split plastic cannula.
Establish your portals close to the joint line.
Be sure to advance the gold trigger fully until it clicks and to advance the second anchor completely before insertion.
Do not torque the inserter because it can bend. Choking up on the inserter is sometimes helpful.
This device cannot reach the anterior third of the meniscus. Tears in this area require conventional inside-out sutures.