Posterior Horn Lateral Meniscal Root Repair Via Double-Tunnel Transtibial Pullout With Meniscocapsular Release

Abstract

Background:

Lateral meniscal root tears often occur in the acute setting in concert with anterior cruciate ligament (ACL) tears. Severe changes in tibiofemoral biomechanics and joint degeneration are encountered when these injuries are either unrecognized or are treated with meniscectomy; therefore, meniscal root surgical repair is now preferred for longer-term benefits. The most common repair techniques include side-to-side and transtibial pull-out repair, which may be performed via single or double transtibial tunnel techniques.

Indications:

The primary indication for lateral meniscal root repair with double transtibial tunnels is suspicion for a lateral meniscal root tear based upon injury mechanism, physical examination findings, magnetic resonance imaging findings, and confirmation with diagnostic arthroscopy.

Technique Description:

The root attachment site is decorticated. Adhesions that cause lateral meniscal root retraction are arthroscopically released. Two separate transtibial tunnels are drilled 5 mm apart from the anterolateral tibia, entering the anterolateral tibia distal to Gerdy’s tubercle and entering the joint at the decorticated lateral root attachment site. Two suture tapes are passed through the torn lateral meniscal root in a vertical mattress configuration and shuttled with a passing suture through the tibial tunnels. The suture tapes are tied over a surgical button on the anterolateral tibia with the knee flexed to approximately 90° while the repair is viewed arthroscopically.

Results:

Lateral meniscal root repairs are safe and have very low reoperation rates. It has been reported that the transtibial pullout repair technique of the lateral meniscus significantly decreases lateral meniscus extrusion compared with other repair techniques in patients with combined ACL reconstruction. Zhuo et al also reported significantly improved postoperative clinical outcomes compared with the preoperative state in patients who underwent pullout repair for posterior lateral meniscal root avulsion tears.

Discussion/Conclusion:

The biomechanical and clinical evidence supports concomitant lateral meniscal root repair in the setting of concurrent ACL injury, and no studies to date have demonstrated a clear harm associated with this procedure. In addition, failure to repair the lateral meniscal root places supraphysiologic loads on the ACL graft and may increase the risk of graft failure.

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 presentation is entitled posterior horn lateral meniscal root repair via double-tunnel transtibial pullout with meniscocapsular release.

The authors’ disclosures are listed on this slide.

Meniscal root tears are grossly underdiagnosed as a source of knee pain and instability, and when left untreated, they may lead to rapid progression of osteoarthritis.^3,4,8

Meniscal root tears have a bimodal distribution with traumatic causes more common in younger active patients, and degenerative etiology more commonly found in patients ages 40 to 60 years. ⁷

Lateral posterior root tears have a strong association with anterior cruciate ligament (ACL) tears and increase the risk of ACL graft failure when not repaired.^2,6,8 Lateral meniscal root repairs are generally indicated in active patients with adequate cartilage and knee stability. ¹

An anatomic reduction is essential for successful root repairs, and a meniscocapsular release is sometimes indicated for chronic root tears that scar out of the joint in a subluxated position.^3,5 Knowledge of the precise anatomic locations of the meniscal root attachments and posterior cruciate ligament (PCL) footprint are required.^5,7

The patient here presented is a 28-year-old man from Europe who underwent a right knee ACL reconstruction with a patellar tendon autograft 2 years prior and had 2 subsequent surgeries to address swelling and mechanical symptoms, but he continued to have functional limitations.

He was then examined at our clinic and physical examination revealed a 1-2+ Lachman with a firm endpoint, tenderness to palpation about the lateral joint line, and decreased knee range of motion.

Plain films of the knee including anteroposterior, Rosenberg, lateral, sunrise, and full-length standing were unremarkable.

Magnetic resonance imaging (MRI) from an outside provider was reviewed and revealed an intact ACL graft, evidence of intra-articular adhesions, and a type 2 lateral meniscal root tear with extrusion. The featured MRI sections show classic signs of meniscal root tear, including the “ghost” sign seen on sagittal views, and fluid extravasation and extrusion seen on coronal sections.^5,7,9

A type 2 meniscal tear, as classified by LaPrade et al, is a radial tear occurring within 9 mm of the root attachment. It is the most common type of meniscal root tear.^5,7

We concluded the extruded meniscus was contributing to early-onset chondromalacia and chronic inflammation, and that a lateral meniscus root repair with lysis of adhesions and possible chondroplasty was indicated.^1,4,6 After explanation of the procedure with discussion of the associated risks and benefits, the patient elected to undergo a surgical repair.

An examination under anesthesia revealed range of motion in the right knee to be from 2-cm heel height to 135° flexion compared with 3 cm to 140° on the left. Lachman test on the right knee was 1-2+ with a good endpoint. His pivot shift was normal. There was no gapping on varus or valgus stress, and his posterior drawer test was negative. The right knee did exhibit decreased patellar mobility compared with the left. The full examination and imaging were consistent with mild adhesions and lack of full extension.

For this technique, standard lateral and medial arthroscopic portals are created and the joint is insufflated with normal saline. Diagnostic arthroscopy revealed very thick adhesions throughout the knee, and therefore, an extensive 3-compartment lysis of adhesions was performed with a curved shaver and coagulation. Chondroplasty with a curved shaver was performed for grade 2 chondromalacia of the proximal patellar pole and trochlear groove.

A small cyclops lesion and intercondylar osteophytes were also removed. The medial meniscal root and ramp attachments were assessed for lesions via the posteromedial drive-through technique, and were found to be normal.

His lateral posterior meniscal root was found to be torn and retracted posteriorly. The lateral meniscal root attachment site is decorticated using a curved shaver and curette; this allows for better healing and bony ingrowth of the meniscal root.

Attention is now turned to the anterolateral approach on the tibia for placement of the tibial tunnels. An incision is made over the anterior tibia and proceeds laterally to elevate the anterior compartment musculature below Gerdy tubercle.

By gently pulling with graspers, the meniscal root is found to be firmly scarred to the posterior joint capsule in a subluxed position. Using arthroscopic straight scissors and a biter, the lateral meniscus is released posteriorly at the meniscotibial area to allow mobility of the posterior horn for an anatomic reduction and repair.

Using a drill guide, a tunnel is drilled using a tibial guide from just beneath Gerdy tubercle to the decorticated site where the lateral root will be attached. This technique ³ involves use of cannulated guide pins, which leave the cannula behind when the pin is removed for smoother passage of suture through the narrow tunnel. A parallel guide is utilized to avoid tunnel convergence for a second tunnel. An arthroscopic suture passing device is utilized to place suture tape through the meniscal root tear. A vertical mattress configuration is utilized for increased contact area and pullout strength. Using a suture loop, the suture tape is shuttled down the cannula. This process is repeated through the other cannula with a simple stitch to reduce the tear edges down to the decorticated tibial surface. Pulling tension on the sutures, the lateral meniscus is pulled back into anatomic position.

The sutures are tied over a surgical button on the anterolateral tibia, and the repair is assessed arthroscopically via a probe. It is noted to be very solidly fixed.

Examination reveals his Lachman is now tighter, validating the role of the lateral meniscus root attachment to anterior tibial translation.

The incisions are closed with suture and dressed in sterile fashion.

Potential complications of meniscal root tear repair include inadequate meniscus reduction and iatrogenic neurovascular or intra-articular injury. Anatomic reduction can be assured with a precise knowledge of anatomical attachment sites, and by utilizing graspers to assess meniscal mobility. In the case of an incomplete reduction, a posterior meniscocapsular release may be performed. Iatrogenic injury may be avoided by using good surgical technique including utilization of drill guides and direct visualization of guide pin placement.^5,6,7,9

For ease of access, portal placement should be carefully considered. Vertically oriented anteromedial and lateral portals positioned just to either side of the patellar tendon will allow a straight drive through the condyles to the meniscal root. More often the senior author will utilize the anterolateral portal as a viewing portal and the anteromedial portal as the working portal. This allows the suture-passing devices to work through the notch as opposed to working in the lateral compartment where often there is limited working space and iatrogenic chondral injury can occur. In the setting of a concomitant lateral sided injury with associated varus instability (increased gapping), there may be adequate working space to flip the working and visualization portals. A parallel guide helps to orient the second tunnel to a correct distance without tunnel conversion. Shuttling the first suture down the tibia before placing the second avoids potential intra-articular suture entanglement.^4,7

Rehabilitation for meniscal root repairs includes restricting range of motion to 0° to 90° of passive knee flexion for the first 2 weeks, after which flexion may be advanced as tolerated. Current guidelines recommend 6 weeks of non-weightbearing followed by partial protected weightbearing with crutches until the patient can walk without a limp. Return to sport should be phased in starting with endurance exercises around 7 weeks, then progressing to strength, and ultimately agility. Full return to sport may be expected around 5 to 6 months, but it is recommended that a serious athlete undergo functional testing for that purpose before release. ⁷

Current literature by LaPrade et al including biomechanical analysis of contact pressures after meniscal root sectioning and transtibial pullout repair supports the chosen method of meniscal root fixation.^3,4

Final postoperative plain films reveal a surgical button on the anterolateral tibia to be in good position.