Anterolateral Segmental Meniscal Allograft Transplantation

Abstract

Background:

The medial and lateral menisci increase joint congruity, stabilization, shock absorption, and proprioception. Deficient menisci provide challenges for orthopaedic surgeons and often require meniscal transplantation. Current techniques for meniscal transplant may sacrifice native healthy meniscus that could be preserved.

Indications:

We present a novel technique for anterolateral segmental meniscal transplant, which serves to replace the deficient anterolateral meniscus with the preservation of the intact posterior midbody and horn.

Technique Description:

Using meniscal root, all-inside, and outside-in meniscal repair techniques, we present a successful segmental anterolateral meniscal transplant.

Results:

While only limited short-term outcomes are available due to the novel nature of this procedure, our patient is following the same protocol as a total meniscal transplant without any complications.

Discussion/Conclusion:

While long-term and larger cohorts are needed, segmental meniscal transplant is a potential novel technique to address non–total meniscal deficiency without sacrificing healthy meniscal tissue.

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 and Indications

This is Emily Whicker, a current fellow at The Steadman Philippon Research Institute in Vail, Colorado. My coauthors and I would like to present the following technique video entitled “Anterolateral Segmental Meniscal Allograft Transplantation.” In this video, we will describe our technique for a segmental anterolateral meniscus allograft transplantation for an insufficient anterior meniscal horn.

The menisci serve to increase joint congruity, stabilization, shock absorption, and proprioception. ¹ Root tears diminish the hoop stress of the meniscus and can lead to a significant increase in joint contact pressures.^2,4 Due to the mobility of the anterior horn, posterior root tears are much more common than anterior tears. ⁴

Deficient menisci prove to be a challenging problem for orthopaedic surgeons and may require meniscal transplantation. However, in a complete meniscal transplantation, healthy native meniscus may be excised to allow for graft implantation. Segmental meniscal transfers preserve native meniscus while restoring hoop stresses and eliminating deficiencies. ³

Case Presentation

We present a case of a 37-year-old man who fell off a ladder at work in 2020; he originally underwent a partial lateral meniscectomy and a revision lateral meniscectomy a year later. As a result of continued symptoms due to a cartilage defect and lateral meniscal deficiency, he then underwent a lateral meniscal transplant and femoral osteochondral allograft transplant in January 2022. However, he continued to have lateral knee pain, catching, and popping.

A year and a half after his meniscal transplant, he returned to the clinic, and due to ongoing lateral knee pain, updated magnetic resonance imaging (MRI) was ordered. MRI revealed adequate integration of the lateral femoral condyle graft and lateral meniscus allograft with intact posterior root and horn, but there was notable degeneration of the anterior horn. Representative coronal and sagittal cuts are shown, noting the diminished anterior horn and absent root.

Technique Description

He was subsequently brought to the operating room and placed supine on the table, and a diagnostic scope revealed that the posterior root, horn, and posterior midbody were intact. However, the anterior midbody and anterior horn were frayed and deficient. The midbody and anterior horn were debrided, and the residual defect measured 3 cm. The decision to proceed with a segmental meniscal transplant was then made. The graft was then prepped on the back table to match the 3-cm defect. Two suture tapes were passed in a luggage tag fashion through the anterior root, and a passing suture was passed through the posterior aspect of the midbody. The approach for the inside-out lateral meniscal fixation was then completed. A 2.4-mm tunnel for the root was drilled and prepped with passing sutures in preparation for passing the graft.

The graft was then passed through a passport cannula (Arthrex) through the anterolateral portal. The anterior root sutures that had previously been prepped through the graft were then shuttled through the anterior tunnel. These were then snapped for later endobutton fixation (Arthrex). We then turned our attention to the midbody, where 3 inside-out sutures were placed across the allograft and posterior midbody interface in a horizontal mattress configuration. These were then retrieved through the previously completed lateral incision and tied down to the capsule. In this video, you can see the placement of the 3 inside-out sutures from the medial aspect of the midbody to the lateral aspect of the midbody. Once appropriate fixation to the posterior midbody was achieved, we then turned our attention to the fixation of the anterior midbody. This was completed with 3 inside-out, capsular sutures that were placed first through the meniscus transplant and then second through the capsule and subsequently tied. The anterior horn was then fixed with 3 outside-in sutures. The first suture was passed with the help of an outside-in meniscal kit (Arthrex), and the PDS sutures were passed and tied through the anterolateral portal, thus providing adequate fixation of the meniscus to the anterior capsule. We then subsequently placed 2 more anterior outside-in sutures with excellent fixation of the allograft to the anterior capsule. The anterior root sutures were then appropriately tensioned and tied over an endobutton (Arthrex) on the anterior tibial cortex. Postoperative x-rays showing endobutton placement are as seen here. Note that 2 additional endobuttons were residual from the prior total meniscus transplant.

Advantages

Advantages of segmental meniscal transplantation are that the intact portion of the native or, in this case, previously transplanted meniscus is preserved. Additionally, in cases where the preserved meniscus is native, the intact mechanoreceptors are not sacrificed for complete meniscal transplantation. Also, the midbody of the meniscus can rely on the meniscocapsular attachments and anchor the posterior aspect of the graft into the native meniscus.

Limitations

Given that this is a new technique, long-term follow-up is not yet available, but this patient is doing well 6 months postoperatively following the total meniscal transplant protocol. Additionally, there is a risk of failure at the allograft–native meniscal interface. While no current biomechanical studies support this novel technique, preliminary data from our institution are encouraging.

Conclusion

While long-term follow-up and larger cohorts are needed, segmental meniscal transplant is a potential novel technique to address non–total meniscal deficiency without sacrificing healthy meniscal tissue.