Clinical relevance of posterior knee arthroscopy in cruciate ligament reconstruction: A comprehensive review

INTRODUCTION

Posterior knee arthroscopy has emerged as a pivotal development in the field of sports medicine and reconstructive knee surgery. The evolution of arthroscopic techniques has allowed surgeons to move beyond traditional anterior portals and gain access to complex posterior structures that were once difficult to visualize and treat. Among these advancements, the posteromedial (PM), posterolateral (PL), and trans-septal portals have become fundamental in improving visualization of the posterior compartment of the knee, enabling more accurate and anatomic reconstruction of cruciate ligaments, particularly the posterior cruciate ligament (PCL), and enhancing management of concomitant lesions such as posterior horn meniscal tears and ramp lesions.^[1-3]

The importance of accurate tunnel placement in cruciate ligament reconstruction has been extensively highlighted in the literature. Non-anatomic tunnel positioning, particularly on the tibial side in PCL surgery, is a common cause of graft failure, persistent instability, and suboptimal outcomes.^[4] Conventional anterior arthroscopic portals alone provide limited visualization of the posterior tibial plateau, often leading to excessively anterior tunnel placement. Posterior portals, by contrast, provide a direct line of sight to the anatomic footprints of the cruciate ligaments, thereby improving surgical precision and reducing the risk of malpositioning.^[5,6]

The trans-septal portal, first described in the early 2000s, represents a particularly significant innovation. By connecting the PM and PL compartments through the resection of the posterior septum, this portal allows for a wide working space and circumferential access to the PCL footprint.^[7] This facilitates complete debridement, accurate tunnel localization, and the management of lesions that would otherwise be challenging through anterior-only or single posterior portal techniques.^[8] Cadaveric studies have confirmed the safety of trans-septal portals when performed with adherence to anatomic landmarks, and large clinical series report low complication rates, with neurovascular injury being exceedingly rare.^[9,10]

The clinical advantages of posterior portals extend beyond technical accuracy. Several studies have demonstrated that posterior visualization enhances the ability to preserve native ligament remnants, which contributes to proprioceptive preservation and potentially improves graft integration.^[11] Moreover, posterior access has been shown to facilitate more reliable repair of posterior horn meniscal and ramp lesions, injuries commonly associated with anterior cruciate ligament (ACL) and PCL tears, which, if left untreated, may contribute to persistent instability.^[12,13] Biomechanical investigations also suggest that grafts placed under posterior arthroscopic guidance are subjected to reduced stress and more closely replicate native ligament kinematics compared to those placed through anterior portals alone.^[14]

Despite these advantages, posterior portal arthroscopy is not without risks and challenges. The proximity of critical neurovascular structures, particularly the popliteal artery and tibial nerve, necessitates precise knowledge of knee anatomy and meticulous surgical technique.^[15,16] Although most reports confirm a high safety profile, complications such as transient saphenous nerve paresthesia, extravasation of fluid, or difficulty in portal creation have been documented.^[17] Furthermore, while posterior portals have been shown to improve tunnel accuracy, evidence regarding their impact on long-term clinical outcomes – such as functional scores, return-to-sport rates, and graft survival – remains mixed. Some prospective studies report improved patient-reported outcomes, while others demonstrate comparable results to conventional techniques despite superior anatomic tunnel positioning.^[18,19]

The growing body of literature underscores the importance of posterior portal arthroscopy as a valuable tool rather than a universal necessity. It provides particular advantages in complex reconstructions, revision surgeries, and cases with concomitant posterior meniscal pathology.^[20] In addition, posterior portals are increasingly being incorporated into advanced techniques such as double-bundle PCL reconstruction and combined ligamentous reconstructions, where accurate visualization of posterior structures is essential.^[21,22] However, their adoption requires specialized training and a steep learning curve, as improper technique could increase risks without conferring benefits.^[23]

In summary, posterior knee arthroscopy with PM, PL, and trans-septal portals represents a major technical advancement in cruciate ligament surgery. It addresses a long-standing limitation of anterior-only arthroscopy by providing direct posterior visualization, facilitating anatomic tunnel placement, and enabling the treatment of associated posterior lesions. Current evidence demonstrates clear technical and biomechanical advantages, although the translation into superior long-term clinical outcomes remains debated. This review aims to provide a comprehensive overview of the techniques, indications, benefits, risks, and clinical relevance of posterior knee arthroscopy, supported by contemporary evidence, and to clarify its role in optimizing cruciate ligament reconstruction.

POSTERIOR ARTHROSCOPIC PORTALS: TECHNIQUES AND APPLICATIONS

PM portal

The PM portal is typically established just proximal to the joint line and posterior to the medial femoral condyle, under direct visualization using a spinal needle for safety guidance.^[12] This portal provides access to the posterior horn of the medial meniscus, the PM capsule, and the medial aspect of the tibial PCL footprint. Clinical studies have demonstrated its utility in both meniscal root repair and in anatomic PCL reconstruction, particularly for tunnel debridement and graft passage^[13] [Figure 1].

Close

Figure 1:

Axial cross-sectional anatomy of the posterior aspect of the knee demonstrating the relationship of arthroscopic posterior portals. The green arrow indicates the PL portal, the blue arrow denotes the PM portal, and the black double-headed arrow represents the trans-septal portal connecting the two compartments through the posterior septum. The popliteal artery and vein are shown posterior to the capsule for reference. AM: Anteromedial, AL: Anterolateral, PL: Posterolateral, PM: Posteromedial.

Export to PPT

Potential risks include iatrogenic injury to the saphenous nerve and vein; however, these can be minimized with correct entry points and a stepwise dilatation technique.^[14]

SEARCH STRATEGY

A comprehensive literature search was conducted to identify relevant studies on the role of posterior portals in knee arthroscopy, particularly in cruciate ligament reconstruction. Four major databases – PubMed (MEDLINE), Scopus, Web of Science, and Embase – were searched from January 1990 to July 2025. The search combined both medical subject headings and free-text terms. The following search string was used with appropriate database-specific adaptations:

(“posterior knee arthroscopy” OR “posteromedial portal” OR “posterolateral portal” OR “trans-septal portal” OR “posterior compartment knee arthroscopy”)

AND

(“anterior cruciate ligament” OR “ACL reconstruction” OR “posterior cruciate ligament” OR “PCL reconstruction” OR “meniscal root repair” OR “ramp lesion”)

AND

(“tunnel placement” OR “footprint” OR “graft positioning” OR “clinical outcomes” OR “complications”).

Reference lists of included articles and relevant review papers were also hand-searched to ensure comprehensive coverage.

STUDY SELECTION

The initial search yielded 1,124 articles across databases. After removal of duplicates, 843 titles and abstracts were screened. Studies were eligible if they:

1. Reported on the creation, safety, or anatomical considerations of posterior portals (PM, PL, and transseptal)

2. Included cadaveric, biomechanical, or clinical data related to cruciate ligament reconstruction

3. Investigated tunnel positioning accuracy, graft kinematics, posterior pathology management (e.g., ramp lesions and meniscal root tears), or reported functional outcomes and complications

4. They were published in English or had an available English translation.

Exclusion criteria were as follows:

• Case reports with fewer than 10 patients, unless describing novel or foundational techniques

• Technical notes without biomechanical or clinical data

• Animal studies

• Non-peer-reviewed material.

Following full-text assessment of 231 eligible studies, 197 were excluded. A total of 34 studies met inclusion standards and were incorporated into the final synthesis for this review [Figure 2].

Close

Figure 2:

Flow diagram illustrating the literature search and study selection process.

Export to PPT

DATA EXTRACTION

Data extracted from the included studies. Extracted variables included:

• Study design (cadaveric, biomechanical, prospective, retrospective, randomized controlled trial, and systematic review)

• Patient demographics (sample size, age, and follow-up duration)

• Surgical details (type of posterior portal used – PM, PL, trans-septal; cruciate reconstructed – ACL or PCL)

• Outcomes assessed (tunnel positioning accuracy, intraoperative visualization, graft biomechanics, patient-reported outcomes, return-to-sport, and revision rates)

• Complications (neurovascular injury, arthrofibrosis, and infection).

DISCUSSION

Posterior knee arthroscopy has undergone substantial refinement over the past two decades, with the evolution of PM, PL, and trans-septal portals fundamentally changing the approach to cruciate ligament reconstruction. These portals provide direct visualization of structures that were previously obscured from the anterior approach, thereby allowing surgeons to perform more anatomic, reproducible, and technically safe reconstructions of both the PCL and ACL. The present review highlights the clinical relevance, advantages, challenges, and potential impact of these posterior portals on patient outcomes.

IMPORTANCE OF POSTERIOR PORTALS

The PM and PL portals offer access to the tibial and femoral footprints of the cruciate ligaments, which are particularly critical in PCL reconstruction, where posterior tibial visualization is mandatory. Historically, surgeons relied on anterior-only approaches, which forced indirect tunnel placement and increased the risk of tunnel malposition and graft impingement. Studies have shown that posterior portals markedly improve accuracy in tunnel creation and reduce complication rates related to neurovascular structures.^[12] The trans-septal portal, first popularized in the early 2000s, further revolutionized cruciate surgery by connecting the medial and lateral compartments through the posterior septum. This allows panoramic visualization of the posterior compartment and enables remnant-preserving techniques, which are increasingly linked to improved proprioception and biological healing.^[6]

IMPACT ON SURGICAL ACCURACY AND BIOMECHANICS

Accurate anatomical reconstruction is central to successful cruciate ligament surgery. Posterior portals provide a direct line of sight to the tibial PCL footprint and the femoral ACL footprint, eliminating the reliance on fluoroscopy or blind instrumentation. Several cadaveric and clinical studies have confirmed that posterior portal use decreases variability in tunnel placement, resulting in reconstructions that more closely replicate native biomechanics.^[24-26] Furthermore, trans-septal visualization facilitates simultaneous assessment of both cruciate ligaments and helps avoid convergence of femoral tunnels in combined ACL-PCL injuries.

CLINICAL OUTCOMES AND REMNANT PRESERVATION

From a clinical standpoint, posterior arthroscopy has been associated with improved subjective and objective outcomes. Remnant-preserving techniques, facilitated by posterior visualization, maintain native mechanoreceptors and vascularity, potentially enhancing proprioception and graft integration. Elazab et al.^[10] demonstrated in their clinical series that posterior arthroscopic PCL reconstruction with careful remnant preservation resulted in superior functional scores and reduced graft failure rates compared to conventional techniques.^[7] Similarly, in ACL reconstruction, posterior portals allow for more anatomic tunnel positioning, which correlates with improved rotational stability and reduced risk of revision.^[9]

SAFETY CONSIDERATIONS AND COMPLICATIONS

While posterior portals provide distinct advantages, their use requires precise anatomical knowledge and technical skill. The proximity of the neurovascular bundle in the popliteal fossa is a key concern, particularly during PL portal creation and transseptal septum resection. However, multiple series have reported that when performed using standardized safe zones, complication rates are extremely low.^[9] We emphasized through our previous study that meticulous technique, blunt dissection, and appropriate portal placement angles mitigate risks and make posterior arthroscopy reproducible and safe even in routine practice.^[10]

COMPARISON WITH ANTERIOR-ONLY TECHNIQUES

Comparative studies between anterior-only and posterior-assisted arthroscopy highlight clear differences. Anterior- only approaches often rely on guide systems or fluoroscopic assistance for tunnel placement, which increases surgical time and radiation exposure. In contrast, posterior portals allow radiation-free direct visualization, reducing both operative complexity and reliance on imaging.^[11] Functionally, patients undergoing posterior-assisted PCL reconstruction consistently show better posterior stability, higher return-to-sport rates, and lower graft attrition than those treated with anterior-only methods.^[12]

LIMITATIONS IN CURRENT EVIDENCE

Despite the growing body of literature, most studies on posterior portals are case series or comparative observational studies, with relatively few high-level randomized trials. Variability in surgical techniques, graft types, fixation methods, and outcome measures complicates direct comparison across studies.^[27-30] Moreover, long-term outcomes beyond 10 years are still limited, and further prospective trials are needed to confirm the durability of posterior-portal-based reconstructions.

FUTURE DIRECTIONS

The continued refinement of posterior arthroscopy is likely to focus on integration with advanced imaging, navigation, and robotics to further enhance precision. Biologically, combining remnant-preserving approaches with biologic augmentation – such as platelet-rich plasma or stem cell-based therapies – may accelerate graft incorporation.^[31-33] The evolution of minimally invasive fixation devices designed specifically for posterior reconstructions also holds promise.

CONCLUSION

Posterior knee arthroscopy using PM, PL, and trans-septal portals represents a transformative advancement in cruciate ligament reconstruction. By improving visualization, enabling anatomic and remnant-preserving reconstructions, and reducing dependence on fluoroscopy, these techniques enhance both technical accuracy and clinical outcomes. While surgeon experience and technical proficiency remain critical to minimizing risks, the accumulated evidence – including our previous contributions- supports posterior portals as an essential component of modern cruciate surgery. Continued high-quality research will further clarify their role in optimizing long-term functional outcomes.