Arthroscopic surgical technique for trans-septal reconstruction of posterior cruciate ligament and popliteus tendon bypass for posterolateral rotatory instability of the knee

Introduction

Background

The posterolateral corner (PLC) of the knee is a complex anatomic structure responsible for posterolateral (PL) stability and rotational stability of the knee (1). The main structures that constitute the PLC are the fibular collateral ligament (FCL) and the popliteus tendon (PLT) complex, which comprises the PLT and the arcuate complex with its primary structure, the popliteofibular ligament (PFL) (2). The main function of the PLC is to stabilize varus, posterior and rotational forces acting on the knee (3). The PFL is a static stabilizer against tibial external rotation, while the PLT alone is a dynamic stabilizer (3). The arcuate complex also prevents posterior tibial translation in conjunction with the posterior cruciate ligament (PCL) (1-3). The prevalence of PLC injuries is difficult to quantify as these injuries often go undiagnosed (4). Isolated injuries are rare. They are usually associated with anterior cruciate ligament (ACL), PCL, or multiligament knee injuries and are often underdiagnosed (4). Prevalence can vary, but it is estimated that they account for 16% of all knee ligament injuries (1,2). The most common mechanism of injury is direct trauma to the anteromedial (AM) aspect of the tibia with a force directed posteriorly and laterally, usually with a hyperextension and external tibial rotation of the knee (5,6). Several classifications have been proposed to describe PL knee instability; the most popular is the Hugston and Fanelli classification (1,7). Recently, Weiss et al. proposed a new classification of dorsal lateral instability of the knee based on anatomic, biomechanic and trauma mechanism considerations (3,8). They underlined four types of dorsal lateral instability of the knee, each with surgical implications. Isolated PCL tears characterize type 1 instability and require isolated PCL reconstruction; type 2 instability is characterized by a PCL and PFL tear, requiring both PCL reconstruction and PLT reconstruction; in types 3 and 4, a low or high-grade FCL tear is also added, requiring the addition of FCL reconstruction (3).

Rationale

PLC reconstruction techniques are historically divided into fibula-based, tibia-based, and tibiofibular-based. These techniques could be either anatomic or non-anatomic reconstructions. Most cases are described as open and invasive techniques, with the need for many grafts and multiple full tunnels in the bone (9-11). Arthroscopy has recently changed the treatment of PLC injuries with less invasiveness, better anatomic landmarks visualization, and potentially quicker recovery (12,13). An arthroscopic popliteal tendon bypass technique was first introduced by Feng et al. (14). Subsequently, Frosch et al. refined and validated this method, demonstrating its accuracy and reproducibility in reconstructing the popliteal complex using a purely arthroscopic approach (15). More recently, open surgical techniques originally described by LaPrade and Arciero have been adapted and clinically validated to arthroscopic procedures (16).

Objective

This work concentrates on Weiss 2 injuries and aims to present a detailed description of an arthroscopic PLT and all-inside trans-septal PCL reconstruction technique based on a four-stranded semitendinosus (ST) graft for the PCL reconstruction and a double-strand gracilis (G) graft for the PLT reconstruction. The PCL all-inside tibial and femoral sockets are retro-drilled under arthroscopic control, an internal brace ligament augmentation (IBLA) is applied to the quadruple ST graft, and fixation is via a loop-adjustable cortical suspension system on both the tibial and femoral sides. Similarly, the PLT tibial socket is prepared in an all-inside, retro-drill manner. At the same time, a mini-open approach is used for femoral socket preparation, with a modified Frosch’s PLT bypass graft technique (15). Fixation of the doubled G graft is obtained through a loop-adjustable cortical suspension system on the tibial and femoral sides, and an IBLA is also added to this graft. Pearls, pitfalls, and tips to avoid complications and achieve reliable results are described thoroughly.

The described procedure was performed at the Centro Traumatologico Ortopedico (CTO) Hospital of Turin, Italy, a tertiary care facility and regional referral center for complex orthopedic and trauma surgery. The surgery was performed in a dedicated operating theatre within the hospital’s surgical unit, which meets the standards of a class I clean room environment. In addition to the lead surgeon, the surgical team included two surgical assistants, a scrub nurse, an anesthetist and two circulating nurses.

We present this article in accordance with the SUPER reporting checklist (available at https://asj.amegroups.com/article/view/10.21037/asj-25-23/rc).

Preoperative preparations and requirements

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for the publication of this study, accompanying images and the video. A copy of the written consent is available for review by the editorial office of this journal.

Careful preoperative patient evaluation should be carried out to address knee instability. The clinical assessment shows a marked positive posterior drawer test and PL drawer test, a positive dial test with external rotation increased more than 15° at 30° and 90° of knee flexion, a slight positive varus stress at 0°, while negative varus stress at 30°, indicating stable FCL and intact ACL and medial collateral ligament (MCL). A positive Hugston’s recurvatum external rotation test should also be assessed on the injured side, compared to the uninjured one (1,17). Preoperative comparative kneeling view X-rays, magnetic resonance imaging (MRI) of the injured side, and long-standing X-rays in coronal and lateral positions are performed. In Weiss 2 PLC injuries, the kneeling view X-ray shows a gross posterior tibial subluxation greater than 10 mm compared to the uninjured side (Figure 1) (17). MRI in chronic conditions is less reliable in detecting PCL and popliteus complex injuries due to the potential apparent restoration of knee intraarticular structures at imaging; however, MRI is fundamental to address any other intraarticular lesion to treat and should always be carried out (18). Anteroposterior and lateral long-standing X-rays give information on coronal alignment and tibial slope of the injured limb; in fact, every malalignment is the first to be restored in chronic multiligament knee injury (19).

Figure 1 Preoperative comparative kneeling view X-ray shows an 11 mm difference between the right normal and left knee with marked dorsal instability. L, left; R, right.

Step-by-step description

Operative setting and patient positioning

In the absence of patient-specific contraindications or anesthetic risks, spinal anesthesia is employed. Routine urinary catheterization is not required. In addition, supplemental oxygen is occasionally administered via a nasal cannula.

The patient is positioned supine on the operating table; a tourniquet is placed around the thigh and inflated. The knee is kept at 90° of flexion with a fixed roller and a lateral post. A retaining pad is positioned at the contralateral hip, preventing the pelvis’s tilt during the intraoperative stress maneuvers. An arthroscopic column is placed on the contralateral side of the affected knee (Figure 2). The skin is prepared with povidone-iodine prior to surgery.

Figure 2 Operative room set up and patient’s positioning. The patient is supine on the operating table with a fixed roller support and a lateral post, maintaining the knee at 90° of flexion. A tourniquet is placed around the thigh to minimize blood loss during the procedure; the arthroscopic column is positioned on the contralateral side concerning the injured knee.

Graft harvesting

Many tendons may be used as grafts to reconstruct the PCL: autologous ST, peroneus longus, quadriceps tendon and allografts. In multiligament knee injuries, the graft choice also depends on the injured ligaments (e.g., in the case of MCL tears, ST can be left on the medial side of the knee and used for MCL reconstruction, while the quadriceps tendon or peroneus longus tendon could be used for PCL reconstruction).

This technique describes autologous quadrupled ST for PCL reconstruction and autologous doubled G for PLT reconstruction. Anatomic landmarks are marked, and a 3 cm skin incision is performed approximately 2 cm medial to the anterior tibial tubercle (ATT) and 4 cm distal to the tibial joint line, in direct line with the hamstring tendons. Dissection is carried out until the sartorius fascia is opened. Hamstring tendons are identified and harvested with the aid of a tendon stripper.

Grafts preparation

Graft preparation is carried out on a back table with the aid of a dedicated workstation. The total length of the tendon for PCL reconstruction should be between 28 and 32 cm, resulting in a total length of 70 to 80 mm of a quadrupled ST graft. Total thickness should be between 9 and 10 mm for PCL reconstruction. Both graft ends are prepped with a No. 2 High-strength non-resorbable suture wire (FiberWire^® No. 2, Arthrex, Naples, FL, USA). The graft is duplicated, passing into a loop adjustable cortical suspension device (Tightrope ABS^TM, Arthrex, Naples, FL, USA). The graft is quadrupled, passing it into a second loop adjustable cortical suspension device (Tightrope RT II^TM, Arthrex, Naples, FL, USA). The graft is secured by knotting the two ends over the ABS^TM adjustable loop. Tension is applied to the graft.

With the graft fully tensioned, multiple passages through all four graft strands are made on each end with FiberWire No. 2 suture to solidarize the four strands, preventing graft loosening and conforming the graft to the socket. A circle is made with the same suture wire at 20 mm from both ends of the graft.

The circle will act as an arthroscopic intraoperative reference of the amount of graft in the sockets. The 20 mm measurement is an arbitrary reference and could be modified depending on the surgeon’s preference. However, having a benchmark on the graft is crucial to guarantee precise intraarticular positioning. The final length is measured in tension, and the diameter is established with a standard sizing block. An annular mark is placed in the middle of the graft with a sterile marker. A high-strength suture tape (FiberTape^®, Arthrex, Naples, FL, USA) is passed through the femoral buttonholes of the RT^® button, configuring an IBLA and a safety loop with a Vycril 0 suture is positioned at the adjustable end of the ABS^TM loop adjustable cortical suspension device acting as a rescue shuttle suture (Figure 3). The total length of the G tendon for PLT bypass should be between 20 to 22 cm, resulting in a total length of 10 to 11 cm of a doubled G graft. The diameter of the graft should be between 6 and 7 mm.

Figure 3 ST tendon preparation. (A) ST tendon after muscle tissue removal. The tendon is cut to the desired length, generally between 28 and 30 cm, so a quadrupled graft of approximately 75 mm is obtained. (B) The two free ends of the tendon are prepped with a No. 2 high-strength non-resorbable suture wire (FiberWire^®, Arthrex). (C) The tendon is doubled, passing into a loop adjustable cortical suspension device (Tightrope ABS^TM, Arthrex). (D) The tendon is quadrupled, passing into a loop adjustable cortical suspension device (Tightrope RT^TM, Arthrex). (E) The two free ends of the quadrupled semitendinosus are knotted together. (F) Multiple passages through all four strands of the graft are made with FiberWire^® No.2 suture, and a circle is made with the same suture wire at 20 mm from both ends of the graft, and an annular mark is placed in the middle of the graft with a sterile marker. (G) Final graft preparation with a high-strength suture tape (FiberTape^®, Arthrex) and a safety loop with a Vycril 0 suture at the ABS loop adjustable cortical suspension device side. 1,2: suture circles. 3: an annular ring with a sterile marker, which serves as a reference point during the procedure. IB, internal brace; ST, semitendinosus.

The G tendon is doubled in a loop adjustable cortical suspension device (Tightrope RT), and its free ends are secured onto a second free-ends dedicated loop adjustable cortical suspension device (Fibertag-Tightrope Implant®, Arthrex, Naples, FL, USA) once the final length of the graft has been established. An IBLA is configured on this graft using the previously described method (Figure 4). At the end of the preparation, the grafts are pretensioned at 70–80 N and soaked in Vancomycin solution (1 g of vancomycin powder diluted in 250 mL of saline solution).

Figure 4 Gracilis tendon preparation. (A) Gracilis tendon after muscle tissue removal. The tendon is cut to the desired length, generally between 20 and 22 cm, so a doubled graft of approximately 10–11 cm is obtained. (B) The tendon is doubled, passing into a loop adjustable cortical suspension device (Tightrope ABS^TM, Arthrex). (C) The two free ends are prepped onto a free-ends dedicated loop adjustable cortical suspension device (Fibertag Tightrope Implant^®, Arthrex). The final length is checked. (D) Annular marks are placed onto the graft as a reference during the arthroscopic phase. 1,2: suture circles. 3: an annular ring with a sterile marker. IB, internal brace; G, gracilis tendon.

Arthroscopy

A full video of the arthroscopic procedure is provided (Video 1). A standard 30° arthroscope is used for all stages of the procedure. Standard anterolateral (AL) and AM portals are developed. Any concomitant intraarticular lesions, such as meniscal tears or cartilage lesions, are addressed and treated if needed.

Development of trans-septal portal

Posteromedial (PM) and PL portals are developed via trans-notch visualization. The shaver is inserted through the PL portal and passes the septum from lateral to medial direction under direct arthroscopic visualization. The posterior neurovascular bundle (PVB) of the knee lies posterior and slightly lateral to the posterior septum. When the knee is bent at 90°, the PVB is more distant from the knee articulation (20); thus, piercing the septum from the PL to the PM compartment and keeping the knee at 90° of flexion significantly reduces any risk of PVB damage.

The camera is positioned in the PM portal, while a 4.2 mm shaver dissects the posterior septum from the PL portal. The shaver is directed toward the tibia’s posterior border, keeping the knee flexed at 90°. Space is created in the posterior compartment, developing the trans-septal portal, and extended distally along the posterior edge of the tibia to visualize the PCL footprint. PCL footprint can be found approximately 15 to 20 mm distal to the posterior tibial plateau and in line or slightly medial to the midline of the posterior tibia. After PCL footprint visualization, the PLT sulcus is identified on the PL side of the tibia. Meniscopopliteal fibers are displaced, and the tibial plateau is exposed down the popliteus sulcus, which is the reference for the popliteus tibial socket drill and lies on the far lateral edge of the tibia, approximately 10 to 15 mm distal to the articular surface (Figure 5).

Figure 5 Left knee, arthroscopic visualization of the posterior compartment of the knee. (A) Posteromedial portal development via trans-notch visualization. (B) Posterolateral portal development via trans-notch visualization. (C) The posterior septum is passed from lateral to medial direction with the shaver under arthroscopic trans-notch visualization. (D,E) The camera is positioned in the posteromedial portal, allowing visualization as the septum is carefully developed with the shaver. (F) The shaver is directed toward the posterior border of the tibia, and the dissection is meticulously carried out until the PCL footprint and the sulcus of the popliteus tendon are reached. B, blade; LM, lateral meniscus; MC, medial condyle; MT, medial tibia; N, needle; PCL, posterior cruciate ligament; PLC, posterolateral capsule; PLP, posterolateral portal; PLT, popliteus sulcus; PMC, posteromedial capsule; PS, posterior septum; S, shaver; T, tibia.

PLT tibial socket preparation

Once the trans-septal portal is fully developed and PCL and PLT footprints are identified, visualizing from the PM portal, a PCL tibial drill-guide (Arthrex, Naples, FL, USA) is introduced from the AM portal, passed lateral to the PCL remnant, and directed at the center of the popliteus sulcus, 10 mm distal from the articular surface. The drill guide is set at 45°, and a small skin incision is performed on the AL tibia at the distal part of Gerdy’s tubercle. The slotted reference cannula allows us to estimate the depth of the tibia. This is paramount as the PVB lies in the same direction and posterior to the popliteus tunnel direction. A retrograde drill Flipcutter II (Arthrex, Naples, FL, USA) is used to drill a 3.5 mm tunnel from the AL tibial cortex and to prepare a 20–25 mm tibial socket in a retrograde fashion, according to the G graft diameter (typically 7 mm), centered on the popliteus sulcus. During the procedure, the knee is kept at 90°, and the tip of the retro drill is protected with the PCL drill guide. A shuttle suture is placed in the tunnel and retrieved with a clamp (Kingfisher, Arthrex, Naples, FL, USA) from the PL portal (Figure 6).

Figure 6 Left knee, arthroscopic visualization of the posterior compartment of the knee. (A) Visualization of the popliteus sulcus with the camera in the posteromedial portal, in trans-septal position. The sulcus lies approximately 10 mm distal to the articular tibial surface and can be reached by displacing the meniscopopliteal fibers. (B) The PCL drill guide is introduced from the anteromedial portal in the posterolateral compartment, passing laterally to the PCL remnant and positioned at the level of the popliteus sulcus. (C,D) The retrograde drill Flipcutter II is introduced in the popliteus sulcus and opened to prepare a retrograde drill, creating the popliteus tibial socket. (E,F) A suture shuttle is introduced in the socket and retrieved from the posterolateral portal. DG, drill guide; F, retrograde drill Flipcutter II; KF, kingfisher clamp; PCL, posterior cruciate ligament; PLT, popliteus sulcus; S, shaver; SH, shuttle suture; T, tibia.

PCL socket preparation

The camera is switched in the PL portal, allowing for a better PCL footprint visualization during the socket preparation. The PCL tibial drill guide is kept in the posterior compartment of the knee and positioned at the center of the PCL tibial footprint, 15 mm distal to the articular surface and lateral to the ligament remnant. The drill guide is set at 55–60° and directed on the medial aspect of the anterior tibia, in the same incision used for hamstring harvesting. A 25–30 mm PCL tibial socket is prepared with a retro-drill Flipcutter II^TM (Arthrex, Naples, FL, USA). The diameter of the socket is established depending on the measured graft diameter. A shuttle suture is placed in the tunnel and retrieved with a clamp (Kingfisher, Arthrex, Naples, FL, USA) from the posterior compartment through the AM portal, passing laterally to the PCL remnant and medial to the ACL (Figure 7).

Figure 7 Left knee, arthroscopic visualization of the posterior compartment of the knee. (A) Visualization of the PCL footprint with the camera in the posterolateral portal once the trans-septal portal is developed. (B) After preparing the popliteus tibial socket, the PCL drill guide is placed at the level of the PCL footprint, approximately 15 mm distal to the tibial articular surface. (C,D) The retrograde drill Flipcutter II is introduced and opened to prepare a retrograde socket at the PCL footprint. (E) A slotted wire delivers a shuttle suture in the posterior compartment. (F,G) The shuttle suture is retrieved in the anteromedial portal with a clamp from the posterolateral portal and the kingfisher clamp from the anterior compartment. (H) Final visualization of the PCL tibial socket. C, clamp arthroscopic clamp; DG, drill guide; F, retrograde drill Flipcutter II; KF, kingfisher; LT, lateral tibia; MT, medial tibia; N, intercondylar notch; PCL, posterior cruciate ligament; PCLF, posterior cruciate ligament footprint; S, posterior cruciate ligament socket; SH, shuttle suture.

The camera is switched to the AL portal. A PCL femoral drill guide is introduced from the AM portal and positioned at the center of the femoral PCL footprint, flush with the cartilage surface. The circular part of the drill guide controls the socket position, avoiding any accidental cartilage lesion. The drill guide is closed at 90° and externally aimed at the medial femoral condyle, where a small incision is performed to prepare the femoral PCL socket. This PCL femoral drill guide configuration allows for an intraarticular socket positioning. Thus, direct arthroscopic visualization of the button fixation on the medial condyle cortex will be accessible during graft positioning. A 20 mm femoral socket is retro-drilled with Flipcutter II^TM (Arthrex, Naples, FL, USA). The diameter of the socket is again previously established depending on PCL graft diameter. The camera is placed in the AM portal and a shuttle suture is passed through the tunnel. The PCL tibial and femoral shuttle sutures are retrieved with a KingFisher® Retriever/Graspers (Arthrex, Naples, FL, USA) clamp. The tibial shuttle suture is kept in the belly of the clamp, while the femur shuttle suture is in the tip of the clamp, avoiding any impingement (Figure 8).

Figure 8 Left knee, arthroscopic visualization of the anterior compartment of the knee from the anterolateral portal. (A) Visualization of the PCLF. A PCL femur drill guide is introduced from the anteromedial portal and positioned at the level of the PCL footprint. (B,C) The retrograde drill Flipcutter II is introduced and opened to prepare a retrograde socket at the PCLF. (D) A slotted wire delivers a shuttle suture in the socket. The tibial and femur shuttle sutures are retrieved in the anteromedial portal with the aid of a kingfisher clamp. In particular, the tibial shuttle suture is kept in the belly of the clamp, while the femur shuttle suture is in the tip of the clamp. (E) Final visualization of the PCL reconstruction preparation with the shuttle sutures ready to deliver the PCL graft at both the femur and tibial side. DG, drill guide; F, retrograde drill Flipcutter II; FSH, femur shuttle suture; KF, kingfisher clamp; MC, medial condyle; PCL, posterior cruciate ligament; PCLF, posterior cruciate ligament femur footprint; PCLR, posterior cruciate ligament remnant; T, tibia; TSH, tibial shuttle suture.

PLT femoral socket preparation

A small skin incision is performed 5 mm anterior and distal to the lateral femoral epicondyle. The iliotibial band (ITB) is dissected along its fibers. Further, smooth dissection is carried out until the femoral insertion of the PLT is identified anterior and slightly distal to the lateral epicondyle at the level of the femoral popliteus sulcus. A 2.4 mm slotted guide wire is inserted at the center of the femoral popliteus insertion, in a lateral to medial direction with a 15° anterior and 20° proximal direction. A cannulated reamer prepares 25–30 mm of the femoral socket based on the guide wire orientation. The diameter of the reamer is based on the G graft sizing, normally 6 to 7 mm. A slotted cannula from the ACL/PCL reconstruction set is placed into the previously created socket, and a closed 3.5 mm retro drill Flipcutter II^TM is used to drill a full tunnel in an antegrade direction into the previously created socket, following the direction of the guide wire, which is removed. The 3.5 mm tunnel allows for the passage of the button of the cortical suspension device. A shuttle suture is finally placed in the tunnel (Figure 9).

Figure 9 Left knee. Open popliteus femoral socket preparation. (A) A 2 cm incision is made on the lateral side of the distal femur, palpating the popliteus femoral sulcus. (B) Dissection is done by opening the ITB and reaching the osseous popliteus sulcus. (C) The popliteus femoral socket is prepared using the aid of a guidewire and a cannulated reamer. (D) A curved Kelly clamp is introduced from the incision to the articulation. G, guide wire; ITB, iliotibial band; K, Kelly clamp; P, patella; PS, popliteus sulcus.

PLT shuttle sutures preparation

The arthroscope is placed in the PM portal, visualizing the PL compartment. A curved Kelly clamp is introduced from the popliteus femoral incision down to the articulation along the PLT course. Care must be taken to respect the anatomic planes. In particular, the Kelly passage must be deep to the ITB and FCL. The popliteus tibial shuttle suture is retrieved from the intraarticular to the femoral incision under direct arthroscopic visualization. The tibial and femoral shuttle sutures are thus prepared to transport the G graft (Figure 10).

Figure 10 Left knee. (A) Direct arthroscopic visualization from the posteromedial portal of the curved Kelly introduced from the incision. (B) The curved Kelly clamp retrieves the tibial suture shuttle in the open incision. (C) The doubled gracilis tendon graft is introduced in the tibial socket from the femoral popliteus incision, the RT button is fixed on the anterolateral tibial cortex, and the graft is tensioned using the circular sutures as reference. The graft is then tensioned in the femoral socket, keeping the knee at 70°. (D) Final arthroscopic visualization of the tensioned popliteus graft. G, gracilis; K, Kelly clamp; LC, lateral condyle; LT, lateral tibia; PL, posterolateral portal; S, tibial socket; SH, shuttle suture.

PCL graft passage and tensioning

PCL shuttle sutures are retrieved together from the AL portal under arthroscopic visualization from the AM portal, avoiding soft tissue impingement. The graft is introduced first into the femoral socket. If the PCL femoral tunnel preparation was intraarticular, the RT button fixation on the medial femoral cortex can be visualized arthroscopically. The RT adjustable loop is pulled until the femoral side of the PCL graft reaches the PCL femoral socket (Figure 11).

Figure 11 Left knee. PCL graft positioning and fixation. (A) Arthroscopic visualization of the anterior compartment of the knee from the anterolateral portal. The graft is introduced from the anteromedial portal. The Tightrope RT button can be visualized, passing in the previously prepared PCL femoral socket. (B) Direct arthroscopic visualization of the RT button correctly fixed on the superomedial femoral cortex. (C) The graft is pulled in the femoral socket, using the previously prepared suture circles as reference. (D) The graft is carried in the PCL tibial socket 18 using a smooth trocar as a pulley. (E) Keeping the knee at 90° of flexion and reducing the posterior drawer tensioning the internal brace, the graft is finally tensioned, pulling on both the tibial and femoral sides, using the circular sutures as references. The internal brace is finally fixed with no more tension applied on the graft. (F) Final arthroscopic visualization of the quadrupled semitendinosus tendon graft replacing the native PCL. C, articular capsule; IB, internal brace; LT, lateral tibia; MC, medial condyle; PCL, posterior cruciate ligament; PCLR, posterior cruciate ligament remnant; S, socket; ST, semitendinosus graft; T, trocar.

The arthroscope is positioned in the PL portal, and the tibial suture shuttle is retrieved to introduce the graft into the tibial socket. The graft is transported into the tibial socket, using a smooth trocar as a pulley to facilitate the passage in the posterior compartment and avoid graft jamming. The knee is kept at 90° of flexion and constant traction is applied on the IBLA exiting from the tibial end, thus reducing the posterior drawer. An ABS^TM 11 mm concave button (Arthrex, Naples, FL, USA) is positioned on the tibial side and charged with the loop-adjustable fixation device wires and the IBLA. The tibial loop-adjustable fixation device is pulled, fixing the graft in the tibial socket under direct arthroscopic visualization. Fine-tuning of the graft tensioning is obtained, pulling both on the femoral and tibial sides and using the circular sutures on the graft as reference (Figure 11). When graft fixation has the correct tension, the IBLA system is finally tied onto the ABS button with no more tension applied.

PLT graft passage and tensioning

The knee is placed in 70° of flexion and neutral rotation. Tibial shuttle sutures transport the G graft from the femoral lateral incision to the AL tibial cortex. The ABS^TM 11 mm concave button is directly visualized until seated on the AL tibial cortex. Gentle tension is applied on the tibial side adjustable loop until the G graft engages the socket (Figure 10). After fixation of the tibial side, the femoral side is shuttled, and the RT button is seated on the AM femoral cortex and gently tensioned, stabilizing the PL rotation of the knee. The graft should be tight in external rotation, regular in neutral rotation, and loose around 20° of internal rotation. The IBLA is finally tied onto the ABS button with no more tension applied.

Final postoperative X-rays are shown in Figure 12.

Figure 12 Left knee. Final postoperative X-rays. (A) Anteroposterior visualization. (B) Lateral visualization. Correct socket positioning and button fixation on the femoral and tibial cortex can be appreciated. Green lines represent the posterior cruciate ligament quadrupled semitendinosus graft fixation buttons; violet lines represent the popliteus by-pass doubled gracilis tendon graft fixation buttons. RT buttons are on the femoral side, while ABS 11 mm buttons are on the tibial side. PCL, posterior cruciate ligament button; PLT, popliteus button.

Postoperative considerations and tasks

A 0–90° range of motion (ROM) is allowed from the first postoperative day. Focus is applied to early full extension recovery in the first postoperative week. Quadriceps muscular strengthening exercises are performed from the first postoperative day. Partial weight-bearing is allowed with crutches for the first month after surgery.

During the first postoperative month, rehabilitation focuses on achieving knee flexion greater than 100°, reestablishing effective quadriceps activation, and gradually regaining independent ambulation. The surgical outcome is considered successful if the patient reports subjective knee stability and clinical assessments—such as the posterior drawer test, PL drawer test and dial test—are negative at follow-up. Return to sports activities is not recommended until 9 to 12 months after surgery, subject to full recovery of knee function, to minimize the risk of complications such as recurrent instability. Clinical follow-up is scheduled at 30 days, 3 months, 6 months and 12 months postoperatively, with additional evaluations as needed.

Tips and pearls

Graft lengths establishment

While the length of the quadrupled ST is usually established prior, given the effortless adaptability of socket lengths, the length of the doubled G graft is always measured intraoperatively due to the poor adaptability of socket lengths. In most cases, the length of the tibial socket is around 25 mm; the length of the intraarticular plus the extraarticular part of the graft is around 50 mm; the length of the femoral socket is around 30 mm. Measures can vary, so measuring the needed intraarticular length each time is essential for adequate graft length. One simple trick is to measure the length of the shuttle suture after retrieving it on the femoral side. The measurement from the femoral to tibial footprint is made and added to the length of the tibial and femoral sockets. In the Author’s experience, this roughly amounts to 10 to 11 cm. Thus, the G tendon is cut at 20 to 22 cm and doubled as previously described.

Trans-septal portal development

During the development of the trans-septal portal, the shaver is used as a blunt dissector to displace the capsule posteriorly and identify the remaining posterior septum fibers to be removed. It is recommended to avoid proximal debridement of the septum as it is unnecessary and may result in potential injury to the middle geniculate artery. The prevalent part of the septum is debrided with the camera in the PM portal, which allows better visualization of the septum and more accessible work with the shaver in the PL portal. However, it is possible to switch the camera from the PM portal to the PL portal and work with the shaver from the PM portal to reach the remaining lateral septum fibers.

Socket creation

During the tibial socket drilling in the posterior compartment, a blunt retractor, such as a smooth trocar or the tip of the shaver, can be introduced from the PM portal and used to move away the posterior capsule, achieving a more expansive space between the posterior tibial edge and the posterior capsule. Every tunnel length and diameter could be adjusted depending on the graft dimension. When necessary, lengthening of the tibial socket is amenable concerning femoral ones because of the significant bone stock in the tibia. While drilling the popliteus femoral socket, a 15° anterior and 20° proximal orientation is helpful in case of multiligament injuries, avoiding any potential conflict with the ACL femoral socket. Similarly, in the case of femoral FCL socket preparation, the FCL socket should be placed at the level of the lateral epicondyle, parallel to the popliteus one. Care must be taken to avoid any trochlear or notch impingement of the tunnel.

Discussion

Surgical highlights

The main finding of this study is that PLC knee instability can be correctly addressed and treated with a reliable and secure technique, which is compatible with associated reconstructions for any multiligament knee injury condition in the chronic and acute setting. The arthroscopic PLT bypass and all-inside trans-septal PCL reconstruction technique have several technical advantages, which are further explained.

Strengths and limitations of arthroscopic PLT and all-inside trans-septal PCL reconstruction technique

Arthroscopy

The arthroscopic visualization with trans-septal portal development allows for a wide work and visualization field, providing highly defined and reliable anatomic landmarks, low invasiveness with minor scar development and less risk of postoperative rigidity (3). Moreover, knee arthroscopy allows for any other associated lesions.

All-inside-out in retrograde drilling

The all-inside-out in technique is a precise and versatile technique that allows the drill guide to be positioned independently from the arthroscopic portals and bone tunnel position (21). Retrograde socket drilling has a bone-spearing effect, particularly useful in multiligament knee injuries, where multiple tunnels must be prepared, and tunnel convergence should be avoided. In this scenario, adjusted directions of the tunnels maintaining the ligament footprint anatomy are crucial to avoid the “tunnel jam” (22). Recent studies showed that graft insertion length in the socket does not affect postoperative knee stability and functional scores in ACL reconstructions (23,24). Thus, the all-inside technique is also tissue-sparing: it requires shorter grafts, while acceptable diameters are obtained by duplicating or quadrupling the grafts. Therefore, a quadrupled ST is optimal to replace a PCL, with a 70 to 80 mm length and 9 to 10 mm diameter, while a PLT tendon is well replaced with a doubled G, which is 10 to 12 mm long and 6 to 7 mm wide.

Adjustable cortical fixation

Recent studies show that cortical fixation versus interference screw fixation has a higher degree of graft healing (25,26). Studies also show that cortical suspension fixation has a minor incidence of tunnel widening concerning screw fixation (27,28). Finally, adjustable loop fixation guarantees highly controlled tensioning of the grafts in the socket, allowing more precise graft tensioning and re-tensioning as needed and high postoperative knee stability.

IBLA

The main described complication after multiligament knee reconstruction in acute treatment is knee stiffness, while in chronic conditions is recurrent knee instability (29). As recently underlined, the risk of knee stiffness is strongly related to the inadequate postoperative rehabilitation protocol, often characterized by long periods of knee immobilization, restricted ROM and no weightbearing for many weeks (30,31). The IBLA, with its unextendible suture tape, acts as a checkrein on the ligament, protecting the graft in the early period and during the ligamentization phase from uncontrolled and excessive stresses on the neo-ligament (32). It should be noted that the IBLA should never be overtightened concerning the graft so that the neo-ligament will withstand physiological stresses that are useful for healing, while overstresses resulting from uncontrolled movements will be protected by the IBLA system. Thus, IBLA has a determinant role in guaranteeing an early aggressive postoperative rehabilitation, with no need for external casts or braces, no significant ROM limitations and allowing a toe-touch weight-bearing from the first postoperative day, preventing knee stiffness and avoiding recurrent knee instability (33).

The arthroscopic PLT and all-inside trans-septal PCL reconstruction

The arthroscopic PLT and all-inside trans-septal PCL reconstruction for PL rotatory instability of the knee has several limitations. A thorough understanding of knee anatomy and advanced arthroscopic skills are required. This is due to the need to operate within the posterior compartment of the knee using a mirror image technique and precise instrument handling. Therefore, such skills should be acquired through a progressive learning curve. In addition, the procedure involves the use of advanced equipment, including retrograde drills and loop-adjustable cortical suspension systems, which add to the overall cost. These tools are essential for accurate graft placement and fixation and for the success of the described procedure. While an advantage related to the proposed technique is that it does not require allografts, which are a significant economic burden. Given these considerations, this technique is best suited for surgeons with experience in knee arthroscopy. In less experienced hands, there is an increased risk of technical errors and prolonged operative times, which may compromise patient outcomes.

Comparison with other surgical techniques and research

There is no consensus in the literature on the best surgical technique for treating PL instability, and clinical results of the different strategies are scarce and elusive (3,34). Historically, open reconstruction procedures showed improved objective and subjective stability (35), while the interest in arthroscopic techniques outcomes increased recently. Weiss et al. published the results of an Arciero-based and a LaPrade-based arthroscopic PLC reconstruction with no vascular complications and satisfactory restoration of PL knee instability (16). Fahlbusch et al. recently published a randomized Arciero’s open versus arthroscopic PL reconstruction results, showing similar functional outcomes and lower surgical times in the arthroscopic technique (13). Similarly, Li et al. demonstrated satisfying outcomes in restoring PL knee stability with the open and arthroscopic PCL and PLT reconstruction techniques (36). Finally, in their technique description, Frosch et al. presented the outcomes of 12 patients who had undergone arthroscopic popliteus bypass reconstruction with good clinical outcomes (15).

Risk and complications

The described arthroscopic reconstruction for PL rotatory instability is a technically demanding technique for several reasons. It requires a deep understanding of the arthroscopic all-inside technique and its potential risks and complications, such as breakage of the retrograde drilling, unintentional retrograde drilling of a complete tunnel, wrong socket length, wrong graft preparation and button malpositioning (37). Moreover, these potential risks and complications are managed in a complex arthroscopic procedure characterized by the development of the trans-septal portal and the sockets preparation in the posterior compartment of the knee with a risk of PVB injury (38). In addition, in treating multiligament knee injuries, the so-called “tunnel jam” is a significant concern and tunnel convergence represents a critical problem to be managed (22,29). Thus, especially in the case of limited experience, the surgeon performing this procedure should be aware of all these risks and the potentially long duration of the surgical procedure.

Implication and actions recommended

Familiarity with the all-inside technique, including the use of retrograde drills and cortical suspensory fixation systems, is essential. Cadaveric training sessions are fundamental prior to performing the procedure, as they enable surgeons to understand and correctly execute each step of the technique. A thorough knowledge of open surgical procedures facilitates the execution of arthroscopic techniques by providing a clear understanding of knee anatomy. Especially in initial cases, it is advisable to be prepared to convert from an arthroscopic to an open procedure if necessary.

Conclusions

Recognizing and addressing PL knee instability is crucial to avoid residual knee instability, chronic pain, impaired knee function, deformity development and failure of the other repaired or reconstructed structures. For the above-discussed reasons, arthroscopic reconstruction for PL rotatory instability is a reliable and safe technique based on solid anatomic and biomechanical principles. It could lead to optimal objective and functional outcomes. Thus, this technique should be considered in the case of isolated Weiss 2 PLC knee instability and in other multiligament knee injuries. However, studies are needed to assess this technically demanding technique’s medium- and long-term effects and potential complications.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the SUPER reporting checklist. Available at https://asj.amegroups.com/article/view/10.21037/asj-25-23/rc

Peer Review File: Available at https://asj.amegroups.com/article/view/10.21037/asj-25-23/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://asj.amegroups.com/article/view/10.21037/asj-25-23/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for the publication of this study, accompanying images and the video. A copy of the written consent is available for review by the editorial office of this journal.

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References

1. Figueroa F, Figueroa D, Putnis S, et al. Posterolateral corner knee injuries: a narrative review. EFORT Open Rev 2021;6:676-85. [Crossref] [PubMed]
2. Nannaparaju M, Mortada S, Wiik A, et al. Posterolateral corner injuries: Epidemiology, anatomy, biomechanics and diagnosis. Injury 2018;49:1024-31. [Crossref] [PubMed]
3. Weiss S, Krause M, Frosch KH. Posterolateral corner of the knee: a systematic literature review of current concepts of arthroscopic reconstruction. Arch Orthop Trauma Surg 2020;140:2003-12. [Crossref] [PubMed]
4. Toyooka S, Persson A, LaPrade RF, et al. Injury Patterns in Posterolateral Corner Knee Injury. Orthop J Sports Med 2023;11:23259671231184468. [Crossref] [PubMed]
5. Pacheco RJ, Ayre CA, Bollen SR. Posterolateral corner injuries of the knee: a serious injury commonly missed. J Bone Joint Surg Br 2011;93:194-7. [Crossref] [PubMed]
6. Moatshe G, Chahla J, LaPrade RF, et al. Diagnosis and treatment of multiligament knee injury: state of the art. Journal of ISAKOS 2017;2:152-61. [Crossref]
7. Fanelli GC, Larson RV. Practical management of posterolateral instability of the knee. Arthroscopy 2002;18:1-8. [Crossref] [PubMed]
8. Chahla J, Murray IR, Robinson J, et al. Posterolateral corner of the knee: an expert consensus statement on diagnosis, classification, treatment, and rehabilitation. Knee Surg Sports Traumatol Arthrosc 2019;27:2520-9. [Crossref] [PubMed]
9. Serra Cruz R, Mitchell JJ, Dean CS, et al. Anatomic Posterolateral Corner Reconstruction. Arthrosc Tech 2016;5:e563-72. [Crossref] [PubMed]
10. Fanelli GC, Edson CJ, Reinheimer KN, et al. Posterior cruciate ligament and posterolateral corner reconstruction. Sports Med Arthrosc Rev 2007;15:168-75. [Crossref] [PubMed]
11. Grimm NL, Levy BJ, Jimenez AE, et al. Open Anatomic Reconstruction of the Posterolateral Corner: The Arciero Technique. Arthrosc Tech 2020;9:e1409-14. [Crossref] [PubMed]
12. Hermanowicz K, Malinowski K, Góralczyk A, et al. Minimally Invasive, Arthroscopic-Assisted, Anatomic Posterolateral Corner Reconstruction. Arthrosc Tech 2019;8:e251-7. [Crossref] [PubMed]
13. Fahlbusch H, Weiß S, Landenberger J, et al. Arthroscopic and open reconstruction of the posterolateral corner of the knee have equally good clinical results: first results of a prospective 12-month follow-up study. Arch Orthop Trauma Surg 2024;144:2745-52. [Crossref] [PubMed]
14. Feng H, Hong L, Geng XS, et al. Posterolateral sling reconstruction of the popliteus tendon: an all-arthroscopic technique. Arthroscopy 2009;25:800-5. [Crossref] [PubMed]
15. Frosch KH, Akoto R, Drenck T, et al. Arthroscopic popliteus bypass graft for posterolateral instabilities of the knee : A new surgical technique. Oper Orthop Traumatol 2016;28:193-203. [Crossref] [PubMed]
16. Weiss S, Krause M, Frosch KH. Clinical results after arthroscopic reconstruction of the posterolateral corner of the knee: A prospective randomized trial comparing two different surgical techniques. Arch Orthop Trauma Surg 2023;143:967-75. [Crossref] [PubMed]
17. Shon OJ, Park JW, Kim BJ. Current Concepts of Posterolateral Corner Injuries of the Knee. Knee Surg Relat Res 2017;29:256-68. [Crossref] [PubMed]
18. Khodarahmi I, Alizai H, Alaia E, et al. MR Imaging of the Knee Posterolateral and Posteromedial Corner Injuries. Magn Reson Imaging Clin N Am 2022;30:215-26. [Crossref] [PubMed]
19. Han G, Zhu K, Zhang F, et al. Application of high tibial osteotomy for chronic multi-ligament knee injury associated with lower extremity malalignment. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 2022;36:18-24. [PubMed]
20. Moran J, Porrino J, Cheng R, et al. An Imaging Overview of the Posterior Septum of the Knee and Trans-Septal Portal Procedure: Normal Anatomy, Indications, and Unique Imaging Considerations. Curr Probl Diagn Radiol 2022;51:562-7. [Crossref] [PubMed]
21. Bosco F, Giustra F, Ghirri A, et al. All-Inside Anterior Cruciate Ligament Reconstruction Technique: Tips and Tricks. J Clin Med 2023;12:5793. [Crossref] [PubMed]
22. Moatshe G, Slette EL, Engebretsen L, et al. Intertunnel Relationships in the Tibia During Reconstruction of Multiple Knee Ligaments: How to Avoid Tunnel Convergence. Am J Sports Med 2016;44:2864-9. [Crossref] [PubMed]
23. Moon HS, Choi CH, Yoo JH, et al. The Graft Insertion Length in the Femoral Tunnel During Anterior Cruciate Ligament Reconstruction With Suspensory Fixation and Tibialis Anterior Allograft Does Not Affect Surgical Outcomes but Is Negatively Correlated With Tunnel Widening. Arthroscopy 2021;37:2903-2914.e1. [Crossref] [PubMed]
24. Mariscalco MW, Magnussen RA, Mitchell J, et al. How much hamstring graft needs to be in the femoral tunnel? A MOON cohort study. Eur Orthop Traumatol 2015;6:9-13. [Crossref] [PubMed]
25. Smith PA, Stannard JP, Pfeiffer FM, et al. Suspensory Versus Interference Screw Fixation for Arthroscopic Anterior Cruciate Ligament Reconstruction in a Translational Large-Animal Model. Arthroscopy 2016;32:1086-97. [Crossref] [PubMed]
26. Sim JA, Kim JM, Lee S, et al. No difference in graft healing or clinical outcome between trans-portal and outside-in techniques after anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc 2018;26:2338-44. [Crossref] [PubMed]
27. Mayr R, Smekal V, Koidl C, et al. ACL reconstruction with adjustable-length loop cortical button fixation results in less tibial tunnel widening compared with interference screw fixation. Knee Surg Sports Traumatol Arthrosc 2020;28:1036-44. [Crossref] [PubMed]
28. Lanzetti RM, Lupariello D, De Carli A, et al. Can the outside-in half-tunnel technique reduce femoral tunnel widening in anterior cruciate ligament reconstruction? A CT study. Eur J Orthop Surg Traumatol 2017;27:659-64. [Crossref] [PubMed]
29. Rodríguez-Merchán EC, De la Corte-Rodríguez H, Encinas-Ullán CA, et al. Complications of surgical reconstruction of multiligament injuries of the knee joint: diagnosis, prevention and treatment. EFORT Open Rev 2021;6:973-81. [Crossref] [PubMed]
30. Fahlbusch H, Krivec L, Müller S, et al. Arthrofibrosis is a common but poorly defined complication in multiligament knee injuries: a systematic review. Arch Orthop Trauma Surg 2023;143:5117-32. [Crossref] [PubMed]
31. Lynch AD, Chmielewski T, Bailey L, et al. Current Concepts and Controversies in Rehabilitation After Surgery for Multiple Ligament Knee Injury. Curr Rev Musculoskelet Med 2017;10:328-45. [Crossref] [PubMed]
32. Lu W, Deng Z, Essien AE, et al. Clinical Research Progress of Internal Brace Ligament Augmentation Technique in Knee Ligament Injury Repair and Reconstruction: A Narrative Review. J Clin Med 2023;12:1999. [Crossref] [PubMed]
33. Dabis J, Wilson A. Repair and Augmentation with Internal Brace in the Multiligament Injured Knee. Clin Sports Med 2019;38:275-83. [Crossref] [PubMed]
34. Maniar AR, White AE, Musahl V, et al. Posterolateral Corner of the Knee: An Update on Current Evaluation and Management Strategies. J Am Acad Orthop Surg 2024;32:e13-23. [Crossref] [PubMed]
35. Moulton SG, Geeslin AG, LaPrade RF. A Systematic Review of the Outcomes of Posterolateral Corner Knee Injuries, Part 2: Surgical Treatment of Chronic Injuries. Am J Sports Med 2016;44:1616-23. [Crossref] [PubMed]
36. Li Y, Zhang H, Zhang J, et al. The Clinical Outcome of Arthroscopic Versus Open Popliteal Tendon Reconstruction Combined With Posterior Cruciate Ligament Reconstruction in Patients With Type A Posterolateral Rotational Instability. Arthroscopy 2019;35:2402-9. [Crossref] [PubMed]
37. Lin TY, Chung CC, Chen WC, et al. Complications following all-inside anterior cruciate ligament reconstruction. Int Orthop 2022;46:2569-76. [Crossref] [PubMed]
38. Cenni MH, do Nascimento BF, Carneiro GG, et al. Popliteal artery injury during posterior cruciate ligament reconstruction. Rev Bras Ortop 2015;50:348-51. [Crossref] [PubMed]