Medial Meniscal Transplant: Technique Video

Abstract

Background:

Meniscal transplantation is a relatively new treatment modality for managing symptomatic meniscal deficiency. The technique differs between lateral and medial meniscal transplants. Medial meniscal transplant fixation techniques include bone bridge, bone plug, and soft tissue options. The goal of this surgical video is to highlight the bone plug fixation technique for medial meniscus transplantation.

Indications:

Indications for this procedure include age younger than 50 years, activity-limiting pain, meniscal deficiency, normal or correctable alignment, ligamentous stability, articular cartilage congruity in addition to predicted compliance with rehabilitation, and realistic postsurgical activity expectations. While these principles apply to both medial and lateral meniscus transplantation, we focus on the medial meniscus in this presentation. Contraindications include asymptomatic lesions, advanced osteoarthritis, alignment that is not correctable, ligamentous instability, irreparable cartilage damage, infection, and inflammatory arthropathy.

Technique Description:

The bone plug paradigm for medial meniscal transplantation involves a more anatomic reduction and fixation method for transplant placement. After the graft is prepared with anterior and posterior bone plugs and a nonabsorbable locking suture, the posterior bone plug is reduced, and then an inside-out meniscal repair technique is completed in a progressively anterior fashion. Following this, the anterior bone plug recipient site is prepared, and then the transplant is fixed at this site.

Results:

Meniscal transplantation demonstrates reasonable pain improvement and survivorship at mid-term outcomes. Risk factors for failure include female sex, severe cartilage damage, and obesity. Further research on outcomes based on the type of reduction technique is warranted.

Discussion/Conclusion:

A meniscal transplant is a potential option for young patients with minimal arthritis and symptomatic meniscal deficiency who have had nonoperative management that has been unsuccessful.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

Background

Fixation strategies for meniscal transplant include the bone bridge technique, ¹² bone plugs, and soft tissue. Prior studies have mixed reports, with some showing no difference between bone plug and soft tissue only, ⁵ and others demonstrating superiority of the bone plug technique over soft tissue fixation. ² For the medial meniscus and its variable horn attachment, ⁴ we have found that the bone plug technique, as opposed to the bone bridge, allows for a sequential posterior-to-anterior fixation paradigm, which may allow for more anatomic transplant reduction and fixation.

Indications for this procedure include age younger than 50 years, activity-limiting pain, meniscal deficiency, normal or correctable alignment, ligamentous stability, and articular cartilage congruity in addition to predicted compliance with rehabilitation and, finally, realistic postsurgical activity expectations. ⁷

Contraindications include asymptomatic lesions, advanced osteoarthritis, alignment that is not correctable, ligamentous instability, irreparable cartilage damage, infection, and inflammatory arthropathy. ⁸

We present a case of a 42-year-old man with a remote knee injury, medial collateral ligament (MCL) reconstruction, initial medial meniscus repair, revision meniscal repair for bucket handle tear, and then 2 meniscectomies. He presented to the clinic 18 years after the most recent surgery with progressive right knee pain and global tenderness to palpation. He was stable on ligamentous examination.

Preoperative planning initially warrants anteroposterior and lateral radiographs of the injured knee, as well as bone length films. Magnetic resonance imaging (MRI) should also be obtained to assess meniscal volume and to rule out concomitant injury.

Plain films of this patient demonstrate prior hardware at the origin of the MCL reconstruction. Bone length demonstrates contralateral valgus knee deformity and neutral coronal alignment of the right knee, with the weightbearing axis passing between the tibial spines. Sagittal MRI demonstrates medial meniscal deficiency with a complex tear at the posterior horn. Coronal MRI again demonstrates a diminutive medial meniscus and associated tearing along with partial-thickness chondral loss overlying the weightbearing aspect of the femoral condyle.

Technique Description

Preoperative examination under anesthesia valgus stress resulted in an audible pop, which was thought to be an injury to the superficial MCL. Anatomic landmarks are identified, including standard arthroscopic portals, expected tunnel exit sites, and exposure to the medial capsule for inside-out repair, are approximated. The meniscal graft will be passed through a medial parapatellar arthrotomy, which is extended from the medial portal incision after arthroscopic preparation.

Diagnostic arthroscopy demonstrates grade 2 cartilage injury in the medial femoral condyle. There was no MCL pie-crusting completed for visualization. There is grade 2 trochlear cartilage change, as well as cartilage fissuring at the inferior aspect of the patella. There were no lateral compartment irregularities. After establishing the anteromedial portal, the medial compartment was probed, demonstrating an intact meniscal root as well as the complex meniscal tearing. The remaining meniscus was debrided to a stable, bleeding recipient rim.

Anterolateral exit of the posterior bone plug tunnel was more appropriate as the authors felt that lateral exit could decrease the risk of bony erosion due to pull of sutures in a lateral trajectory as opposed to a medial exit with less bone bridge. This was drilled with an anterior cruciate ligament over-the-top guide.

Here, we can see the intra-articular tunnel exit with a shuttling suture. Attention was turned to a medial parapatellar arthrotomy where the remaining anterior medial meniscus was excised. The exposure for the inside-out meniscus repair was also completed.

Bone tunnels were prepared on the transplant tissue on the back table. These measured approximately 7 mm in diameter with an 8-mm depth. The bone plugs were prepared with a microsagittal saw for precision cuts. Luggage tag locking nonabsorbable sutures were passed through the meniscal tissue just medial to the bone plugs to provide over-the-top fixation of the bone once seated in the tunnel. The proximal side of the allograft was clearly marked for later orientation.

Posterior sutures were pulled via the shuttle stitch through the posterior bone tunnel. Suture was then passed through the posterior medial aspect of the graft while outside the recipient. These stitches were then passed in an inside-out fashion to allow for assistance with reduction at both the posterior root and the posteromedial corner. The posterior bone plug suture and the first inside-out suture were then tensioned to introduce the graft into the joint and provisionally reduced. The posterior plug can be seen here, well reduced. Here is our setup for inside-out repair. Using zone-specific cannulas, double-needle fiber tapes were passed in a vertical mattress orientation. These sutures were sequentially placed, alternating above and below the meniscus to ensure appropriate reduction. After tying the suture tape pairs over the medial capsule, appropriate reduction and fixation in the area of inside-out repair can be seen here. The anterior meniscus was directly visualized and repaired to the recipient rim. Then, a trapezoidal-shaped bony recess was created with osteotomes. Then, an Arthrex root guide was used at the lateral proximal tibial incision and directed to the anterior root. A shuttling stitch was then used to pull the anterior root suture through the newly made tunnel. A bone tamp was used to press-fit the rectangular bone block into the defect. The sutures secured to the anterior root bone block were then placed into a 4.75-mm anchor at the proximal lateral incision. Our incisions can be seen here.

The risk of graft mismatch should be minimized preoperatively with the use of cross-sectional imaging aids in graft selection. The surgeon should utilize patient x-rays as well as a second check to ensure the meniscus to be transplanted is not smaller than the size of the plateau. With increased mismatch, there may be inadequate tibial plateau coverage or potentially bothersome redundant tissue.

The bone plug recipient site should be carefully selected. Secure guide placement is essential for the posterior plug. The anterior plug location is determined after suturing the meniscus from posterior to anterior.

Sometimes the bone plug fractures posteriorly when trying to pass it into the recipient site. It is important to have the sutures going securely through the root of the meniscus several passes, so it is not dependent solely on the bone for fixation.

Results

Postoperatively, we make patients toe-touch weightbearing while locked in extension with no range of motion (ROM) out of brace for 2 weeks. From 2 to 6 weeks, patients can come out brace for ROM exercises and begin a mild strengthening protocol. At 6 weeks, patients are beginning to come out of brace. Once the patient ambulates with a normalized gait and achieves full ROM, they should begin a strength-focused regimen. From 6 to 12 weeks, this regimen should focus on a graduated return to full strength. Return to running should be initiated at 3 to 4 months postoperatively, and sport-specific training should be initiated at 6 to 9 months. These parameters can be further evaluated with functional testing by our physical therapy colleagues throughout the rehabilitation period. Additional patient guidance on their presurgical activity level and postsurgical activity level should be discussed, as these implants are meant to potentially allow for return to the same-level sport, although this is not a guaranteed outcome.

Discussion

Current literature suggests that meniscal transplant demonstrates improvement in patient-reported outcome measures^6,11,15,16 and pain. ¹¹ Further studies identify reasonable graft survivorship of 84% at 5 years. ³ Return to sport varies throughout the literature, ⁹ with a recent systematic review reporting a time frame between 8.6 and 12.6 months following surgery in most studies reviewed.^1,13 However, the heterogeneity of the retrospective evidence (indications, age, medial vs lateral, fixation, postoperative protocol) limits the quality of systematic reviews and meta-analyses ¹³ and warrants ongoing research on the topic. Risk factors for failure include female sex, severe cartilage damage, ¹⁴ and obesity. ¹⁰ A meniscal transplant can be a reliable option for young patients with minimal arthritis and symptomatic meniscal deficiency who have had nonoperative management that has been unsuccessful.

Here are our references. Thank you for your time and attention.