All-Inside Repair of a Radial Lateral Meniscal Root Tear With an Anterior Cruciate Ligament Injury

Abstract

Background:

Root tears are functionally compromising injuries that require an anatomic repair for functional restoration of native joint mechanics. Posterior root tears of the lateral meniscus are commonly associated with anterior cruciate ligament (ACL) ruptures as lateral root tears contribute to anterolateral rotational instability. Two-tunnel transtibial root repair allows for root repair with superior pullout strength and can be combined with ACL reconstruction to treat this injury pattern.

Indications:

Two-tunnel transtibial root repair is indicated in active patients with meniscal root tears that have low-grade chondromalacia (grade II or less). It is contraindicated in patients with advanced degenerative changes (grade III-IV), severe mal-alignment, and extrusion related to advanced degenerative changes; those who cannot complete postoperative rehabilitation; and patients with significant medical comorbidities.

Technique Description:

After repairing a vertical horn tear of the posterior medial meniscus, a vertical tear of the posterior root of the lateral meniscus was observed. Following preparation of the anatomic footprint, 2 transtibial tunnels were drilled and sutures were passed and secured using a surgical button over the anterior tibial cortex. Horizontal repair of the tear was then performed using 2 all-inside devices. Subsequently, an ACL reconstruction was performed.

Results:

At 11 months postoperative, the patient has continued to progress as expected. She was able to ambulate without pain, had a symmetric and balanced gait, and was able to return to running.

Discussion/Conclusion:

Lateral meniscal root repairs using 2 transtibial tunnels and concomitant ACL reconstruction have yielded good and reliable clinical outcomes with low failure rates and low rates of revision surgery.

Graphical Abstract.

This is a visual representation of the abstract.

Download video file ^{(156.1MB, mp4)}

DOI: 10.1177/26350254211071080.M1

Video Transcript

For this presentation, we wil be discussing a case involving an all-inside repair of a radial lateral meniscal root tear with an associated anterior cruciate ligament (ACL) injury requiring reconstruction.

Posterolateral root tears are traditionally defined by the presence of a radial tear occurring within 9 mm of the meniscal attachment site on the tibia. The posterolateral meniscal root serves an important role as a secondary stabilizer to the pivot shift and during rotational loading. The reported prevalence of posterolateral meniscal root tears has been reported to occur in approximately 2.8% with prior investigations also reporting posterolateral meniscal root tears to be more likely to occur acutely, in the setting of an ACL injury, with tears reported in 7% to 14% of patients sustaining ACL ruptures. ⁶ The presence of a posterolateral meniscal root tear has been shown to increase the risk of early-onset osteoarthritis and progression, underscoring the importance of proper identification on physical examination and advanced imaging, as well as appropriate treatment.

Our patient is a healthy 20-year-old female athlete presenting with right knee pain located to the anterior-medial and anterior-lateral aspects of the knee after landing from a jump playing basketball 3 days prior to her clinical presentation. The patient reported consistent, sharp, stabbing pain to the knee with associated swelling and instability. She reported using nonsteroidal anti-inflammatory and ice without experiencing any substantial relief.

On physical examination, the patient was a healthy 20-year-old female demonstrating an antalgic gait with a moderate effusion to the right knee appreciated on examination. The patient reported medial and lateral joint-line tenderness upon palpation, as well as swelling, that limited her range of motion from 0° to 90° of flexion. She was also noted to have an unstable Lachman test and a positive pivot shift. Anterior-posterior and lateral x-rays of the right knee were obtained demonstrating a well-preserved medial and lateral patellofemoral joint-spaces without evidence of fracture or dislocation.

On magnetic resonance imaging (MRI), it was noted that the patient had evidence of an ACL tear along with tearing of the lateral meniscal root, as well as a longitudinal tear within the medial meniscus. The MRI must be carefully evaluated to identify any signal change suggesting a tear to the lateral meniscus posterior root, including extrusion on the coronal cuts and a ghost sign on the sagittal view. However, these tears can often be difficult to visualize on imaging, necessitating a thorough evaluation arthroscopically, as failure to address and treat these lesions of the posterior root may result in inferior outcomes and persistent rotational instability.

On the contrary, concurrent meniscal root repair has been shown to improve ACL reconstruction outcomes.

Following discussion of the risks, benefits, and alternatives of surgery, the patient elected to proceed with operative intervention in the form of ACL reconstruction using a bone-patellar-bone autograft, as well as a lateral posterior meniscal root repair and an associated medial meniscal repair.

Following a preoperative examination under anesthesia, which demonstrated a 2B Lachman test and a positive pivot shift, a standard bone-patellar-bone harvest was performed using an 8-cm longitudinal incision, with bone plugs measuring 20-by-10 mm for the patella and 25-by-10 mm for the tibial tubercle. Standard anterior-medial and anterior-lateral portals were then established, and evaluation of the ACL demonstrated a full-thickness tear.

A vertical longitudinal tear to the posterior horn of the medial meniscus was appreciated, which was then repaired using 2 all-inside meniscal repair devices. A vertical tear of the lateral meniscus with root involvement was then seen. After locating the anatomical location of the root, a curved ring curette was used to prepare the footprint.

The root may then be repaired using a single versus 2 transtibial tunnels that better recreates the root attachment on the tibia effectively restoring tibiofemoral contact mechanics. Using a root aiming device, 2 pins were created through the tibial tunnels, which were then over drilled with a 2.5-mm cannula. Sutures were first passed using a suture-passing device through the posterior aspects of the lateral leaflet, followed by shuttling of the suture through the cannula using a looped-passing wire. A suture was then passed through the anterior aspect of the lateral leaflet, followed by shuttling through the cannula.

Two sutures were then passed through the medial leaflet and subsequent shuttling through the cannula.

The sutures were then tied down over a surgical button on the anterior cortex of the tibia. Two all-inside meniscal repair anchors were then used to repair the gap between the radial tear and the posterior horn of the lateral meniscus.

A standard ACL reconstruction was then performed.

Postoperatively, the patient will be non-weight-bearing for a total of 6 weeks. Beginning on postoperative day 1, the brace is to be unlocked from 0° to 90°, allowing for early range of motion beginning at 2 weeks following surgery. Pain is to be treated using a combination of nonsteroidal anti-inflammatory medications, as well as ice and Tylenol, and the next step is to begin physical therapy focusing primarily on knee range of motion and subsequently strengthening. It was discussed with the patient that the anticipated return to sport time was 9 to 12 months following surgery, while. X-rays demonstrated well-positioned tunnels and graft without evidence of hardware failure, lucency, or fracture-dislocation.

Posterior root tears of the lateral meniscus are defined as radial tears that occur within 9 mm of the meniscal insertion in the posterior tibial attachment. Root tears are functionally compromising injuries that are equivalent to a total meniscectomy. ⁸

Currently, known risk factors have included male patients, below the age of 30 years, and those participating in activities in which they sustain a contact injury to the knee. ³ Lateral meniscal root tears are injuries commonly associated with concomitant ACL ruptures. ² Furthermore, nonanatomic root repairs are nonfunctional and are associated with significantly elevated contact pressures and decreased contact surface area.^1,5,9 Two-tunnel transosseous meniscal root repair has demonstrated increased pullout strength allowing for improved anatomical fixation of the meniscal root. ⁴

Current outcomes evaluating the surgical treatment of patients with combined lateral meniscal root tears and associated ACL tears requiring reconstruction demonstrated improved functional outcomes with lower rates of osteoarthritis progression seen radiographically. ¹⁰ The success rate of lateral meniscal root repairs has also been demonstrated, yielding significant improvements in patient-related outcomes without evidence of repair failures or requiring revisions. ⁸

Transtibial repairs have the increased benefit of immediately restoring tibiofemoral contact pressures and contact surface areas to that of an intact knee at time zero. ⁴ This has made them a very attractive treatment option for this challenging pathology. Relative to other techniques, like the use of an all-inside technique with suture anchors, transtibial repair facilitates anatomic repair with a high degree of accuracy. ⁷ It is a less technically demanding procedure with precise repeatability. ⁷ There is also an orthobiological benefit with tunnel drilling, as it allows for progenitor cells and growth factors from the marrow to coat the repaired construct. ⁷ This is analogous to the superior clinical outcomes in meniscus repairs with transosseous tunnels drilled due to concomitant ACL reconstruction.

Among the transtibial root repair techniques, there has been increasing discussion on the relative efficacy of 2-tunnel repair against single-tunnel repair. To date, there is no biomechanical or clinical data comparing the 2 in the more mobile lateral meniscus. In the medial meniscus, it has been theorized that 2-tunnel techniques are better able to incorporate the supplemental “shiny white” fibers of the posterior meniscus leading to greater strength. To test this hypothesis, a 2015 biomechanical study by LaPrade et al sought to compare single- and 2-tunnel transtibial repair of posterior root tears in the medial meniscus using a human knee model. ⁴ The authors found no significant difference between the 2 groups in terms of displacement after 1000 cycles or ultimate load at failure. This prompted the authors to conclude there may not a biomechanical advantage to 2-tunnel drilling relative to single-tunnel drilling.

Key pearls of this procedure include the utilization of an arthroscopic curette to remove the overlying chondral tissue to create a vascular bony bed at the root repair site to maximize healing while appropriately spacing transtibial tunnels approximately 5 mm apart with a recommendation to drill the posterior tunnel first. Accessory portals may be used to ease suture passage. It is critical to ensure appropriate meniscal mobilization prior to root repair to ensure an anatomic repair. This is done by releasing any restrictive adhesions or scar tissue prior to repair.

We generally use a cortical button during root fixation on the tibia due to its low profile and decreased risk for irritation. Tunnel placement and trajectory may be confirmed using fluoroscopy, if needed, while creation of an additional posterolateral portal can be made and used to facilitate suture passage through the meniscal root if standard anterior portals are too restrictive.

Commonly encountered pitfalls include performing a nonanatomic repair, which will not effectively restore tibiofemoral congruity and potentially increase the risk of ACL graft failure. Suture management is critical to avoid soft tissue bridges when shuttling the sutures out of the portal and through transtibial tunnels.

Thank you very much for watching our video presentation.