1. Irreparable medial or lateral meniscal tear or partial meniscus loss, with intact rim. Most important, the synthetic meniscus substitute is not intended for the treatment of total or subtotal meniscus defects. Ideally, the defect length should be limited to 5 to 6 cm.

2. Skeletally mature male or female patients.

3. Patients aged 16 to 50 years.

4. Stable knee joint or knee joint stabilization procedure within 12 weeks of index procedure.

5. International Cartilage Repair Society (ICRS) classification of 3.

6. Patient willing and able to give consent to participate in the clinical study, follow rehabilitation protocol, and attend or undergo all follow-up visits and procedures.

1. Total meniscus loss or unstable segmental rim defect

2. Multiple areas of partial meniscus loss that could not be treated by a single scaffold

3. Any significant malalignment (varus or valgus)

4. ICRS classification of greater than 3

5. Body mass index of 35 or higher

Anesthesia and Positioning

The Actifit meniscal scaffold is placed in the subject’s knee using a standard arthroscopic surgery procedure and standard equipment. Implantation is usually performed with use of spinal or general anesthesia at the discretion of the orthopedic surgeon. The use of a tourniquet is optional. The surgeon may prefer thigh fixation to achieve appropriate valgus or varus stress positioning.

Examination

Verification of cartilage status and integrity of the meniscal rim and both the anterior and posterior horns should be performed. In the case of a tight medial compartment, distending the medial collateral ligament using the outside-in puncture method (several passes with a spinal needle from outside in) or the inside-out pie-crusting release technique described by Steadman allows the surgeon to adequately visualize both the femoral and the tibial cartilage status and to create an adequate working space for meniscus reconstructive surgery.

Portals

The implantation requires the usual small incisions for anteromedial and anterolateral portals, with an optional central transpatellar tendon portal. To allow for easy insertion of the scaffold, an enlargement of the portal used for insertion of the device may be required (the size of the little finger is typically sufficient). In addition, a posteromedial or posterolateral incision may be required if an inside-out meniscal fixation technique is used. Additional small incisions are made around the joint line if an outside-in technique is used.

Specific Steps

The specific steps of the procedure are outlined in Box 59-1.

Preparation of the damaged meniscus includes surgical debridement and removal of all pathologic tissue and ensuring that the resulting defect site extends into the vascularized red-on-red or red-on-white zone of the damaged portion of the meniscus. Lesions situated farther away from the synovial border are known to have only very limited healing potential and therefore should be excluded from this type of meniscoplasty. For enhancement of healing, the meniscal rim may be punctured to create vascular access channels. Gentle rasping of the synovial lining may further stimulate meniscal healing (Fig. 59-1). The meniscal defect should be measured along the curvature of its inner edge using the accompanying specially designed meniscal ruler and meniscal ruler guide. Actifit is then measured and with a scalpel is cut to fit in such a place and manner as to ensure that sterility is maintained at all times. To allow for shrinkage caused by suturing of the spongelike material and to ensure a snug optimal fit into the prepared defect, oversizing of the length by 10% is advised (3 mm for defects smaller than 3 cm and 5 mm for defects 3 cm or larger). To achieve a perfect fit of the scaffold with the native meniscus at the anterior junction, the anterior side should be cut at an oblique angle of 30 to 45 degrees (Fig. 59-2). Although the Actifit material is strong and flexible, the device should be handled with care and manipulated with a blunt-nosed grasper, such as the Acufex Grasper Tissue Tensioner (Smith & Nephew). Marking the cranial and caudal meniscal scaffold surface with a sterile marking pen avoids positioning problems. The Actifit device should be clamped at the posterior part of the scaffold and placed into the knee joint through the anteromedial or anterolateral portal. To ensure a good initial position of the meniscal scaffold and facilitate further fixation, the surgeon may place a vertical holding suture in the native meniscus tissue to bring Actifit through the eye of this holding suture.

Fixation of Actifit is achieved by suturing the scaffold to the native meniscus tissue. All standard meniscus suturing techniques may be used; the suturing technique employed depends on the location of the defect and the surgeon’s experience and preference. All-inside suturing has proven effective, and this technique is commonly used for the posterior horn and posterior part of the rim. For the middle and anterior part of the rim, all-inside, inside-out, and outside-in techniques may be used. Horizontal sutures with an outside-in technique are commonly used for the anterior horn and posterior horn.

The manufacturer recommends standard commercially available size 2.0 nonresorbable sutures, such as polyester or polypropylene and braided or monofilament sutures.

Fixation of the device should begin with a horizontal all-inside suture from the posterior edge of the scaffold to the native meniscus. Suturing should be secure; however, attention must be paid not to overtighten sutures, because this may alter and indent the surface of the scaffold. In line with well-known meniscal suturing techniques, the distances between the sutures should be kept to approximately 0.5 cm. Each suture should be placed at one third to one half of the scaffold’s height, as determined from the lower surface of the scaffold.

After suturing, if required, the scaffold may be further trimmed and fine-tuned intra-articularly with a basket punch. Once the scaffold has been securely fixed, stability of the fixation is tested by use of the probe and movement of the knee through a range of motion (0 to 90 degrees).

To enhance the healing response, bone marrow aspiration can be performed from the notch area and directly applied on the dry scaffold after implantation. Figure 59-3 depicts a scaffold 1 year after implantation showing full peripheral integration to the meniscus rim.

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Open Repair of Posterior Shoulder Instability Autologous Chondrocyte Implantation in the Knee Arthroscopic Rotator Cuff Repair: Double-Row Techniques Surgical Treatment of Posterolateral Instability of the Elbow Primary Repair of Osteochondritis Dissecans in the Knee Arthroscopic Meniscus Repair: All-Inside Technique

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