Transtibial Tunnel and Combined Hashtag Inside-Out Repair of Lateral Meniscus Radial Tear With Marrow Venting

Abstract

Background:

Radial meniscal tears have traditionally been managed with a partial meniscectomy. Recently, repair of these tears has become more popular. The inside-out method of meniscal repair has increased stability provided by a greater number of sutures and smaller insertion holes from the suture placement compared to all-inside sutures. Transtibial tunnels are often used for the repair of meniscus root tears but can also be used to restore apposition for widely separated radial meniscus tears. Marrow venting procedures may be utilized to release biological agents into the knee to improve healing.

Indications:

Transtibial tunnel and combined hashtag inside-out repair of the lateral meniscus with marrow venting is indicated for radial meniscus tears that are widely separated.

Technique Description:

A scissor biter was used to release the lateral meniscus anteriorly and posteriorly to allow for edge reapposition. A transtibial tunnel guidepin with a cannula was drilled, entering the anteromedial tibia medial to the tibial tubercle and exiting where the posterior leaf of the radial tear was planned to be reduced. After confirmation that the cannula was properly located, a self-capture meniscus suture device was used to place a vertical mattress suture at the rim of the posterior leaf of the tear. The suture was shuttled down the cannula and secured to the anteromedial tibia over a cortical button. Two hashtag inside-out vertical mattress sutures were placed on each side of the radial tear, and 4 further horizontal mattress sutures were used to reduce the radial tear to an anatomic position to complete the hashtag repair. Four microfracture awl holes were created on the lateral aspect of the intercondylar notch for a marrow venting procedure.

Results:

Transtibial tunnel radial and combined hashtag inside-out repair with marrow venting can be used to repair complicated complete radial tears of the lateral meniscus and presumably slows the progression of arthritis.

Discussion/Conclusion:

Previous management of retracted radial meniscus tears has focused on partial meniscectomy. We describe a technique that repairs lateral meniscus radial tears using a transtibial tunnel to pull the posterior aspect of the tear into position, a hashtag inside-out meniscal repair technique, and a marrow venting procedure to assist with biological healing.

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

This is a video presentation depicting an arthroscopic-assisted transtibial tunnel and combined hashtag inside-out repair of a separated lateral meniscus radial tear with a marrow venting procedure.

Shown here are the senior authors’ disclosures.

Background

Radial meniscus tears in young patients are often the result of trauma and have traditionally been managed with partial meniscectomy.^7,11 More recently, attempts have been made to instead repair the meniscus. Radial meniscus tears transect the circumferential collagen fibers of the meniscus and interfere with their ability to withstand hoop stress. ¹² They are often complicated and difficult to fix, but repair should be attempted if possible. Current techniques of radial meniscal tears include the inside-out, outside-in, and all-inside techniques. The all-inside technique is the method of choice for many surgeons as it reduces surgical time and requires fewer incisions. ⁶ Despite its technical demand and the use of an additional incision, the inside-out method of meniscal repair provides greater stability due to a greater number of sutures and a smaller insertion hole into the meniscus substance. ³ Transtibial tunnels are often used for the repair of meniscal root tears but may be indicated when the edges of a radial tear are separated significantly. This can occur in the acute phase with a full-thickness radial tear or in the chronic phase when the meniscus is scarred in place, requiring a release and more robust fixation to approximate the edges of the tear. ² A single tunnel is best utilized when only one side of the radial tear requires significant reapproximation. If both sides are significantly displaced, 2 tunnels may be required. Furthermore, a marrow venting procedure may be utilized to induce healing.

Indications

A 16-year-old boy presented to our office for evaluation of left knee pain after a football injury 4 weeks prior. Since sustaining the injury, he had been experiencing persistent pain, swelling, and mild mechanical symptoms. His symptoms worsened with weightbearing activity. He had limited relief with rest, ice, activity modification, or over-the-counter analgesics.

Examination of the patient's left knee revealed a range of motion of 5 cm heel height to 140° of flexion, compared to 5 cm heel height to 140° of flexion on the right. The left knee was tender to palpation over the lateral joint line and was otherwise nontender throughout. There was minimal quadriceps muscle atrophy on the left compared to the right. The left knee was stable to Lachman's, varus and valgus stress, and posterior drawer tests.

Plain radiographs revealed a neutral weightbearing alignment bilaterally. There was no evidence of acute fracture or soft tissue abnormalities. All joint spaces appeared preserved with no signs of collapse.

Select coronal, sagittal, and axial magnetic resonance imaging (MRI) findings are displayed. These show a complex radial tear of the lateral meniscus at the junction of the anterior horn and midbody. The edges of the tear are poorly approximated on the axial view. The medial collateral ligament appears thickened and the anterior cruciate ligament (ACL) has mildly increased signal, but these structures are stable on examination. His physes are nearly completely closed.

In summary, the findings on physical examination were confirmed with imaging, and the diagnosis of a subacute complete separated radial tear of the left lateral meniscus was confirmed. The left lower extremity was in neutral alignment. A plan was made for surgical repair of the meniscus tear using an arthroscopy-assisted transtibial tunnel and combined hashtag inside-out meniscus repair with marrow venting.

Technique Description

The patient was induced under general anesthesia. To begin the procedure, medial and lateral parapatellar portals were created. An arthroscopic camera was inserted into the joint, and the joint was insufflated with normal saline. The medial meniscus and articular cartilage of the medial compartment were normal. The ACL and posterior cruciate ligament were also normal. The articular cartilage of the lateral compartment was normal, but a complete radial tear of the lateral meniscus was confirmed with intact lateral compartment cartilage. A lateral incision along the distal lateral joint line at the inferior aspect of the iliotibial band was then made down to the lateral capsule. The posterior portion of the radial tear was adhered posteriorly and separated from the anterior radial tear leaf secondary to scarring. The posterior portion was unable to be reduced when tugged on with a grasper. This confirmed the MRI findings and warranted the use of a transtibial tunnel.

A scissor biter was used to gradually release the meniscus both anteriorly and posteriorly until both edges of the tear could be properly approximated. At this stage, an additional medial portal was created to aid in the release. A curette was used to mark where the posterior portion of the meniscus would be pulled anteriorly with the transtibial tunnel. The tunnel location is chosen based on the desired location for the approximation of the edge of the radial tear. In this case, just the posterior edge of the tear required approximation. An incision was made medial to the tibial tubercle and the periosteum was elevated. Next, a transtibial meniscal guide was used to drill a guide pin with a cannula into the area marked with the curette. A straight FirstPass Mini Suture Passer (Smith & Nephew) was used to place a vertical mattress suture into the rim of the posterior radial tear leaf about 5 mm from the tear margin. The sutures should be placed about 5 to 7 mm from the edge of the tear to avoid placing them through degenerative tissue, which can increase the risk of suture pullout. The suture was shuttled down the transtibial cannula and tied over an EndoButton (Smith & Nephew) on the anteromedial tibia to pull the posterior portion of the meniscus tear anteriorly to approximate the edges. Two vertical mattress sutures were placed on each side of the radial tear to act as rip-stop sutures for the hashtag repair. Three horizontal mattress sutures were placed on the superior surface of the meniscus, and 1 additional suture was placed on the inferior surface of the meniscus. By placing the vertical sutures first, the horizontal sutures could be pulled tighter without as high a risk of pulling through the meniscus with the vertical sutures acting as rip-stop sutures. These were used to reduce the tear to an anatomic position. In the process of doing this, it was noted that any varus stress of the knee tended to make the gap open up.

Next, 4 microfracture awl holes were created on the lateral aspect of the intercondylar notch to facilitate a marrow venting procedure. The microfracture awl holes are placed in the lateral femoral notch to avoid iatrogenic damage to the cruciate ligaments. Once the repair was complete, the deep and superficial tissues were closed with sutures and a knee immobilizer was applied in full extension.

Results

This procedure has several potential complications, including neurovascular damage, postoperative stiffness, and a higher risk of retear. ⁹ There is increased risk of neurovascular damage with more posteriorly located meniscus tears than was found in this case. Such damage can be avoided by directly exposing the posterior capsule and retracting the neurovascular structures at risk. ¹⁰ A tablespoon may even be used to retract and protect the neurovascular bundle. Furthermore, the lateral head of the gastrocnemius muscle can be used to protect the neurovasculature. ³ Postoperative stiffness can be avoided with early postoperative rehabilitation focused heavily on knee mobilization. ³ Lastly, due to being located primarily in the avascular, white-white zone of the meniscus, radial tears have limited healing ability and are prone to retear. ¹ Care should be taken to note any movement that places increased strain on the repair—in this case, varus stress. This patient should avoid any cross-legged movement that will place increased stress on the repair. Additionally, patients undergoing this procedure should remain nonweightbearing for 6 weeks to protect the repair during healing.

Postoperative rehabilitation guidelines for this operation include remaining strictly nonweightbearing on the left lower extremity for 6 weeks. The patient will avoid applying any varus stress to the operative knee for the first 4 months postoperatively. He will also avoid squatting and lifting for 4 months following surgery. The patient may return to sport at 6 months, given he has passed strength testing requirements. Physical therapy was initiated the morning after surgery for quadriceps activation, edema control, and knee motion. Radiographs will be taken at 1 day postoperatively and repeated at 4 months postoperatively to check the joint space and assess button position.

Discussion/Conclusion

Historically, radial meniscus tears in young, active patients have been treated with partial meniscectomy. Meniscus repair has been shown to delay signs of early arthritis, and healing of tears has been documented with second-look arthroscopy; therefore, repair of such injuries has become more popular among surgeons.^5,6 Previous studies have reported that the inside-out technique provides improved subjective and objective clinical outcomes for patients with radial meniscus tears. ⁸ Transtibial tunnels are commonly used for ACL repairs but may also be of use when repairing separated radial or radial meniscus root tears.^4,13 Radial tears notoriously have difficulty healing due to being located primarily in the avascular zone of the meniscus. The transtibial tunnel may aid in healing, especially for tears that are separated significantly, and provides an additional treatment option for patients and physicians. Future studies should look to develop a classification system for radial tears and associated surgical techniques based on tear morphology.

Radiographs were obtained on the first postoperative day in the clinic. There was no evidence of acute fractures or soft tissue abnormalities. All joint spaces were preserved compared to prior imaging, and the hardware was intact and in the proper position.