Abstract
Posteromedial meniscocapsular separation of the knee has received renewed interest, with many articles describing a high incidence in association with anterior cruciate ligament injury. Various techniques have been described to address these lesions using all-inside meniscal repair sutures or using rotator cuff repair instruments through the posteromedial portal. Most orthopaedic surgeons are accustomed to using the “inside-out” meniscal repair technique with a double-armed suture. This technique is cost-effective and, in our opinion, more efficient in repairing such tears. We present our technique of repairing peripheral meniscocapsular lesions using an inside-out meniscal repair system. We believe that this technique is easily reproducible, is less time-consuming, and ensures a good “bite” of the capsular tissue, producing a robust repair.
The posteromedial meniscocapsular attachment of the knee has attracted attention since its initial description,1 and this attention is increasing. This area has been a neglected area of the knee, probably because of difficult visualization and access, as well as a lack of understanding of its biomechanical importance.2 A deficient meniscocapsular attachment destabilizes the meniscus, may contribute to early failure of anterior cruciate ligament (ACL) reconstruction, and may lead to further damage to the meniscus and chondral surface of the medial compartment. Most authors now agree that posteromedial meniscocapsular separations need to be repaired.1, 2, 3, 4, 5, 6, 7, 8
Posteromedial meniscocapsular separation is typically associated with ACL injuries.4 The incidence of such lesions has been reported from 16.6% to as high as 23.2%.2, 5 Acute tears are classified as hemorrhagic, incomplete, or complete, whereas chronic lesions are classified as scarring, elongation, or complete tears. Posteromedial meniscocapsular separation has also been described in combination with semimembranosus disruption.6
Meniscocapsular separation destabilizes the meniscus, which makes it prone to further tears.3 It also makes the articular surface of the femur and tibia prone to injury. Resection surgery results in loss of a large portion of the meniscus, hence the need for repair. An unstable posterior horn of the medial meniscus is an indirect arthroscopic sign of peripheral laxity at the meniscocapsular junction, and careful assessment is required to rule it out.6
Such tears are difficult to identify on magnetic resonance imaging, and the diagnosis is usually made intraoperatively. A systematic approach to diagnosis is required to identify and address this area, including the need for repair. Of particular importance is the fact that the capsular part is sagging in relation to the meniscus: Some of these lesions heal in this position, making the area capacious—the so-called elongated chronic lesion.1
Various techniques have been described for repair including all-inside techniques such as the FasT-Fix technique (Smith & Nephew, Andover, MA). Another approach uses rotator cuff repair devices through the posteromedial (PM) portal.6, 7
We have modified the inside-out repair technique slightly and present our technique for repairing these peripheral meniscocapsular separations. We believe that this technique is easy, reproducible, and efficient in repairing posteromedial meniscocapsular separation.
Surgical Technique
Our technique is an inside-out repair using No. 2-0 FiberWire meniscal repair needles (13-inch inside-out meniscal repair needles; Arthrex, Naples, FL) in an ACL-deficient knee (Video 1). The patient is placed in the supine position under general anesthesia. The left lower limb is positioned in a custom-made bolster, and the tourniquet is inflated. A high-definition image capture system (Synergy; Arthrex) with a 30° viewing angle arthroscope is used. The steps of the procedure are described in the following sections (Table 1).
Table 1.
Steps for Inside-Out Repair of Posteromedial Meniscocapsular Separation
| 1. Creation of portals |
| 2. Diagnostic round |
| 3. Evaluation of meniscus stability |
| 4. Incision for retrieval of sutures and placement of knots |
| 5. Freshening and approximation of tear |
| 6. Passage of sutures |
| 7. Knot placement |
| 8. Assessment of repair |
Creation of Portals
The standard anterolateral (AL) portal is used for viewing, and the anteromedial (AM) portal serves as the instrument portal. In addition, the standard PM portal is created by direct visualization.
Diagnostic Round
The initial step is a diagnostic round through the AL portal; the posteromedial recess is visualized by passing the arthroscope between the medial femoral condyle and posterior cruciate ligament and flexing the knee to 90°. The surgeon rotates the light cord to turn the face of the arthroscope toward the posteromedial side and internally rotates the tibia to bring the meniscocapsular area into view. This is followed by identification of the lesion (Fig 1).
Fig 1.
Approach to posteromedial meniscocapsular junction in anterior cruciate ligament–deficient knee. Viewing is performed from the anterolateral portal with placement of the arthroscope between the medial femoral condyle and posterior cruciate ligament. The knee is in 90° of flexion, and the tibia is in internal rotation. Adequate rotation of the light cord brings the posteromedial meniscocapsular separation into view. The rent in the meniscocapsular junction is easily visible, and one can easily appreciate the sagging of the capsule (arrows) in relation to the meniscus.
Evaluation of Meniscus Stability
In the presence of a meniscocapsular separation, the arthroscope is withdrawn from the area to visualize the medial meniscus from the AL portal and the medial meniscus is probed to check for instability. If found to be stable, the area is rasped with a 90° diamond rasp (Acufex; Smith & Nephew) and standard ACL reconstruction is completed. If the tear is found to be associated with an unstable meniscus displacing into the joint, the tear is repaired. In this case the meniscus is found to be unstable and displacing into the joint.
Meniscocapsular Separation: Inside-Out Repair Technique
Incision for Retrieval of Sutures and Placement of Knots
A 2-cm incision is made medially, posterior to the superficial medial collateral ligament. Exposure is performed up to the level of the capsule after the sartorial fascia is incised, with dissection further into the interval between the superficial medial collateral ligament and posterior oblique ligament for retrieval of sutures and knot placement.
Freshening and Approximation of Tear
The posteromedial tibia is rasped through the AM portal. The meniscocapsular area is freshened by shaving the proliferated synovium and fibrous tissue through the PM portal using a shaver (Arthrex). To prevent sagging of the capsule, it is elevated with a grasper holding the capsule through the PM portal and raising it to the desired level.
Passage of Sutures
Visualization then returns to the medial side through the AL portal for passage of No. 2-0 FiberWire meniscal repair needles (Arthrex). A curved cannula (Acufex; Smith & Nephew) is placed at the desired position with the curve medially to prevent posterior and lateral passage of the needles. The neurovascular bundle lies lateral to the midline at this level, and it is safe to use this technique provided that the angle of needle passage is posteromedially. The tear is kept in approximation with the grasper through the PM portal throughout the procedure. Sutures are placed in a vertical or horizontal fashion. The passage of sutures through the tear is visualized by placing the arthroscope between the posterior cruciate ligament and medial femoral condyle (Fig 2).
Fig 2.
Repair of meniscocapsular separation. Viewing is performed from the anterolateral portal with placement of the arthroscope between the medial femoral condyle and posterior cruciate ligament. The knee is in 90° of flexion. After passage of sutures through the meniscus, the grasper lifts the sagging capsule to the desired level; the FiberWire suture (arrows) is shown exiting the posteromedial meniscocapsular separation with an adequate amount of capsular tissue between the sutures, which are placed in horizontal fashion.
Knot Placement
The sutures are retrieved through the medial incision, and knots are placed over the capsule posteromedially. The standard ACL reconstruction procedure is completed.
Assessment of Repair
The posteromedial repaired area is revisualized to assess the integrity of the repair. Such assessment may not be possible after ACL graft tightening.
Discussion
Meniscocapsular separations can be occult on magnetic resonance imaging and challenging to visualize on arthroscopy.8 The factors to be considered in repairing meniscocapsular separations are the need for repair, the proximity to neurovascular structures, the complexity of the procedure, the risk of cartilage damage, the presence of capsular over-tightening, the need for placement of multiple sutures, and the thin capsular tissue posteriorly.
We use an algorithm to treat meniscocapsular separations found during ACL surgery based on the instability of the meniscus associated with these lesions. Repairing such lesions adds to the operative time, and over-tightening the posteromedial capsule results in restriction of range of motion. Because the capsular arm of the lesion is sagging in relation to the meniscus, it is essential to elevate the capsular arm before suture passage.
By using the inside-out technique, placement of sutures through the meniscus and capsule ensures that a good amount of capsular tissue is included in the repair. The ease of passage of suture needles through the AM portal, in comparison to direct placement of sutures through the limited working space of the PM portal, makes this procedure less time-consuming. The correction of the sagging of the capsule in relation to the meniscus results in an anatomic repair that may be easily reproducible. The technique is also cost-effective in comparison to other all-inside procedures in which specialized sutures and implants need to be placed.
The main drawback of our procedure is the requirement for a 2-cm incision and development of the interval between the medial collateral ligament and posterior oblique ligament for placement of knots. In addition, the surgeon must ensure that the capsular arm of the tear is kept in approximation through the PM portal throughout the procedure.
We believe that the described technique is easily reproducible, is less time-consuming, is cost-effective, and ensures a good repair. The long-term results need be studied in detail, including assessment of the integrity of the repair with second-look arthroscopy and radiologic evaluation at follow-up.
Footnotes
The authors report that they have no conflicts of interest in the authorship and publication of this article.
Supplementary Data
The inside-out repair technique for addressing medial meniscocapsular separation with an unstable meniscus is shown in a left knee with anterior cruciate ligament insufficiency. The patient is in the supine position with the leg placed in a bolster. The anterolateral portal is the viewing portal, and the anteromedial and posteromedial portals are used as instrument portals. Inside-out meniscal repair needles (Arthrex) are used for repair.
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Supplementary Materials
The inside-out repair technique for addressing medial meniscocapsular separation with an unstable meniscus is shown in a left knee with anterior cruciate ligament insufficiency. The patient is in the supine position with the leg placed in a bolster. The anterolateral portal is the viewing portal, and the anteromedial and posteromedial portals are used as instrument portals. Inside-out meniscal repair needles (Arthrex) are used for repair.