Arthroscopic meniscal repair with use of the outside-in technique

The outside-in technique of arthroscopic repair is effective for repair of most meniscal tears. The overall indications for the use of this technique are similar to those for the commonly used inside-out technique. The outside-in technique is especially useful for suturing the anterior horn of the meniscus as well as for suturing meniscal replacement devices such as a collagen meniscal implant or a meniscal allograft. Other specific advantages of this technique include the ability to predictably avoid neurovascular injury without the need for a large posterior incision. A particular disadvantage is the difficulty of achieving perpendicular orientation of sutures when a tear is adjacent to the site of attachment of the posterior horn. Use of the inside-out technique or an all-inside implant is suggested for these tears. The use of this suturing technique is facilitated by attention to several technical points. The knee should be maintained in flexion for repair of tears of the lateral meniscus (to avoid injury to the peroneal nerve) and in nearly full extension for repair of the posterior aspect of the medial meniscus (to avoid injury to the saphenous nerve and its branches). Care must be taken to avoid tying the sutures around a branch of the saphenous nerve during repair of the medial meniscus. The sutures should be retrieved through a cannula in the anterior portal to avoid the entrapment of the sutures in soft tissue. A probe can be used to prevent displacement of the inner fragment of a bucket handle tear when the needles are placed across the tear, as the entering needles may push the torn fragment into the knee. A vertical suture orientation is preferred in order to evenly co-apt the meniscus to the capsule. If knot-end sutures (so-called Mulberry knots) are used, 2 sutures can be vertically stacked, with 1 on each surface of the meniscus. If a mattress suture is used, a vertical orientation is easily achieved with the outside-in technique. Use of an exogenous fibrin clot is suggested for isolated tears. The clot can be secured to the site of repair by a suture that has been placed through a spinal needle with the outside-in method. Delayed weightbearing should be considered as postoperative management for patients who have had repair of a tear with a radial component or repair of a complex tear in which a fibrin clot was used. Previous studies have demonstrated that the location of the tear and the condition of the anterior cruciate ligament are important factors in determining the success of meniscal repair. The overall results with use of the outside-in technique are comparable with those reported with use of the inside-out method. Patients with concomitant tears of the medial meniscus and the anterior cruciate ligament should have combined meniscal repair and reconstruction of the anterior cruciate ligament. As healing was demonstrated in 8 of 13 patients with an unrepaired tear of the anterior cruciate ligament, consideration should still be given to meniscal repair in patients who refuse reconstruction of the anterior cruciate ligament. In this setting, it may be advisable to use multiple permanent sutures, and the patient must be counseled regarding the higher rate of failure with this approach. Repairs of the lateral meniscus have a higher rate of success, and repair of the lateral meniscus should be considered even in the presence of injury of the anterior cruciate ligament.