An anatomic study of the posterior septum of the knee

The tibial capsular reflection and septum in posterior compartment are safe and reliable soft-tissue landmark for tibial tunnel drilling in posterior cruciate ligament reconstruction

PURPOSE

To investigate the validity of using tibial capsular reflection and septum in the posterior compartment as landmark during posterior cruciate ligament (PCL) reconstruction (PCLR).

METHODS

Anatomic measurements were obtained for 12 fresh human cadaveric knee specimens to observe the spatial position of the tibial insertion of the PCL in relation to the posterior septum and the capsular reflection in the posterior compartment. Sixty patients who underwent reconstruction of the PCL between 2020 and 2023 were also retrospectively investigated. The tibial tunnel was replaced in all patients using the same method (with reference to the tibial capsular reflection and the posterior septum). The placement of the tibial tunnel was assessed using X-ray fluoroscopy intraoperatively and computed tomography and three-dimensional reconstruction postoperatively.

RESULTS

All fibres in the tibial insertion of the PCL in the 12 cadaveric specimens were located in the posteromedial compartment, adjacent to the posterior septum. The inferior border of the PCL insertion is adjacent to the tibial capsular reflection, which is attached at the champagne glass drop-off of the posterior tibia. In our previous cases, none of the patients experienced postoperative or intraoperative complications such as neurovascular injury, and the angle between the pin and the PCL facet was 93.1 ± 3.9° as measured on intraoperative radiographs. The mean distance from the centre of the tibial tunnel outlet to the inferior border of the PCL insertion was 5.6 ± 1.1 mm, and the distance from the centre of the tibial tunnel outlet to the outer border of the PCL insertion as a percentage of the length of the inferior border of PCL insertion was 42.2 ± 6.3%.

CONCLUSION

The tibial capsular reflection and septum in the posterior compartment are safe and reliable soft-tissue landmark for tibial tunnel drilling in PCLR.

LEVEL OF EVIDENCE

Level Ⅳ.

A modified anatomical posterior cruciate ligament reconstruction technique using the posterior septum and posterior capsule as landmarks to position the low tibial tunnel

BACKGROUND

Lowering the exit position of the tibial tunnel can improve the clinical efficacy of posterior cruciate ligament (PCL) reconstruction, however, there is no unified positioning standard. This study aimed to use novel soft tissue landmarks to create a low tunnel.

METHODS

A total of 14 human cadaveric knees and 12 patients with PCL injury were included in this study. Firstly, we observed the anatomical position between the PCL, posterior septum, and other tissue, and evaluated the relationship between the center of the low tibial tunnel (SP tunnel) and posterior septum and distal reflection of posterior capsule, and using computed tomography (CT) to evaluate distance between the center of the SP tunnel with bony landmarks. Then, evaluated the blood vessels content in the posterior septum with HE staining. Finally, observed the posterior septum and distal reflection of the posterior capsule under arthroscopy to explore the clinical feasibility of creating a low tibial tunnel, and assessed the risk of surgery by using ultrasound to detect the distance between the popliteal artery and the posterior edge of tibial plateau bone cortex.

RESULTS

In all 14 cadaveric specimens, the PCL tibial insertions were located completely within the posterior medial compartment of the knee. The distance between the center of the SP tunnel and the the articular surface of tibial plateau was 9.4 ± 0.4 mm. All SP tunnels retained an intact posterior wall, which was 1.6 ± 0.3 mm from the distal reflection of the posterior capsule. The distances between the center of the SP tunnel and the the articular surface of tibial plateau, the champagne glass drop-off were 9.2 ± 0.4 mm (ICC: 0.932, 95%CI 0.806-0.978) and 1.5 ± 0.2 mm (ICC:0.925, 95%CI 0.788-0.975) in CT image. Compared with the posterior capsule, the posterior septum contained more vascular structures. Last, all 12 patients successfully established low tibial tunnels under arthroscopy, and the distance between the posterior edge of tibial plateau bone cortex and the popliteal artery was 7.8 ± 0.3, 9.4 ± 0.4 and 7.4 ± 0.3 mm at 30°, 60° and 90° flexion angels after filling with water and supporting with shaver in posterior-medial compartment of knee joint.

CONCLUSIONS

A modified low tibial tunnel could be established in the PCL anatomical footprint by using the posterior septum and posterior capsule as landmarks.

MRI study of the cruciate ligaments and menisco-femoral ligaments of the knee

PURPOSE

It has been argued that the meniscus-femoral ligaments disappear with age. We therefore analyzed the presence of the meniscus-femoral ligaments, in MRI.

MATERIALS AND METHODS

We measured the PCL, ACL and MFL, noting their presence or absence in 120 Knee MRIs, 51 in women and 69 in men. All knees underwent MRI in the coronal, sagittal and axial planes. T1 and T2 weighted sequences were obtained. A descriptive statistical study of all the variables was carried out, and a comparative study was performed between sexes, sides and age groups.

RESULTS

The MFLp was more frequent, found in 67 (55.8%) cases, than the MFLa, in 36 (30%) cases, and both together were present in 27 (22.5%) knees. We found a strong correlation between ACL length and PCL length (p = 0.001), we found no correlation between the presence of the posterior MFL either with age (p = 0.307) or with sex (p = 0.779) or side (p = 0.733). We also found no relationship between the presence of the anterior MFL and age (p = 0.553), or sex (p = 0.913), or laterality (p = 0.082).

CONCLUSION

We found a strong correlation between ACL length and PCL length. In our study, the presence of the posterior MFL was more frequent, being present in 55.68%, while the anterior MFL was found in 30% of the knees. We did not observe that the presence of LMF decreases with age.

Heterotopic Ossification in the Posterior Septum of the Knee Excised by an Arthroscopic Dual Portal Technique: A Case Report

CASE

We present a 15-year-old adolescent girl with acute onset knee pain and a lesion in the posterior septum (PS) believed to be an infectious process on initial investigations. This was excised successfully using a combination of transseptal and transnotch portals and proven to be a case of heterotopic ossification (HO) within the PS with an excellent outcome within 4 weeks. Our case is unique for the pathology that occurred and the technique of excision.

CONCLUSION

HO in the PS is a rare pathology that can be treated arthroscopically using a combination of portals. Removal causes complete resolution of symptoms.

Arthroscopic Identification of the Knee Posterolateral Corner Structures and Anatomic Arthroscopic Posterolateral Corner Reconstruction: Technical Note - Part 1

Arthroscopic assessment of posterior compartments of the knee and the posterior aspect of the proximal tibial and fibula is challenging because of the relative proximity of the neurovascular bundle. This Technical Note describes a reproducible arthroscopic surgical approach in a cadaveric model that aims to identify and expose the popliteus tendon, posterior fibular head, fibular collateral ligament popliteal fibular ligament, biceps femoris tendon, and peroneal nerve.

Arthroscopic removal of loose bodies using the accessory portals in the difficult locations of the knee: a case series and technical note

Background

It is often technically demanding to find and remove loose bodies in several difficult locations like the popliteus hiatus and posterior compartment arthroscopically. We aim to present the technical aspects of establishing some special accessory portals to achieve arthroscopic removal of the loose bodies in these locations.

Methods

From September 2010 to July 2017, 76 patients underwent removal of loose bodies in the popliteus hiatus and posterior compartment arthroscopically using some special accessory portal techniques. An auxiliary extreme lateral approach was established to remove loose bodies in the popliteus hiatus; a double-posteromedial portal was applied to handle loose body removal in the posteromedial compartment, and the posterior trans-septal portal was needed for loose body removal in the posterolateral compartment. Functional outcomes were evaluated using Lysholm score, Tegner score, and International Knee Documentation Committee (IKDC) score, respectively.

Results

Seventy-six patients (24 males and 52 females, average age 54.9 ± 11.4) finished the follow-up visit at 3 weeks after surgery. There was no statistically significant difference among the three groups in demographics. All the patients were performed following the special technique. According to a comparison of knee joint scores before and after surgery, all the patients obtained good prognosis using some special accessory portals in loose body removal.

Conclusions

With the help of the above accessory portals under endoscopic visualization, loose bodies in the popliteus hiatus and posterior compartment of the knee can be safely and effectively removed.

Loose body as an obstacle for posterolateral arthroscopic portal formation in the knee joint

In this report, we present a case with difficult arthroscopic posterolateral portal formation due to loose body located in posterior compartment. These loose bodies are responsible for pain, decreased range of motion and cartilage damage in the knee joint. By making the posterior trans-septal portal prior, posterolateral portal could be made without difficulty completing the planned arthroscopic procedure.

Arthroscopic approach to the posterior compartment of the knee using a posterior transseptal portal

Arthroscopic surgery of the posterior compartment of the knee is difficult when only two anterior portals are used for access because of the inaccessibility of the back of the knee. Since its introduction, the posterior transseptal portal has been widely employed to access lesions in the posterior compartment. However, special care should be taken to avoid neurovascular injuries around the posteromedial, posterolateral, and transseptal portals. Most importantly, popliteal vessel injury should be avoided when creating and using the transseptal portal during surgery. Purpose of the present study is to describe how to avoid the neurovascular injuries during establishing the posterior three portals and to introduce our safer technique to create the transseptal portal. To date, we have performed arthroscopic surgeries via the transseptal portal in the posterior compartments of 161 knees and have not encountered nerve or vascular injury. In our procedure, the posterior septum is perforated with a 1.5-3.0-mm Kirschner wire that is protected by a sheath inserted from the posterolateral portal and monitored from the posteromedial portal to avoid popliteal vessel injury.

Arthroscopic Posterior Knee Capsulotomy for a Fixed Flexion Contracture in a Ten-Year-Old Boy Due to a Hypertrophied Ligamentum Mucosum: A Case Report

CASE

Knee flexion contractures are difficult to treat effectively. We present the case of a ten-year-old boy with a flexion contracture due to a hypertrophied ligamentum mucosum treated with an arthroscopic posterior capsular release. The patient obtained full extension and maintained it at the time of final follow-up.

CONCLUSION

This case represents a unique cause of an impinging ligamentum mucosum and provides anecdotal support to the concept of an arthroscopic posterior capsular release as a safe and effective option for flexion contractures.

A simple method to minimize vascular lesion of the popliteal artery by guidewire during transtibial posterior cruciate ligament reconstruction: a cadaveric study

PURPOSE

To compare the outside-in transtibial lateral and medial approaches for posterior cruciate ligament (PCL) reconstruction regarding the guidewires and popliteal artery integrity.

METHODS

Twenty-two human cadaveric knees were used. A PCL tibial aimer was arthroscopically placed within the PCL footprint through the anteromedial portal for the medial approach and through the anterolateral portal for the lateral approach. For the medial approach, the drill guide was introduced through the anteromedial tibial cortex and the guidewire was advanced with the reamer beyond the posterior tibial cortex. For the lateral approach, the drill guide was introduced through the anterolateral tibial cortex and the guidewire was advanced with the reamer beyond the posterior tibial cortex. After this, the knee was dissected. The depth distance (DD) was defined as the distance between the popliteal artery and the tibial posterior cortex projected at the tibial level at which the guidewire intersected or passed by the artery. The guidewire travel distance was calculated as the distance the guidewire had to advance beyond the tibial cortex to intersect the popliteal artery or pass by it.

RESULTS

With the medial approach, the popliteal artery was intersected in all knees with a mean DD of 12.20 mm and a mean guidewire travel distance of 15.90 mm. With the lateral approach, the popliteal artery was not intersected in any knee; its mean medial distance from the artery was 4.8 mm at a DD of 10.05 mm. There was a significant difference in the popliteal artery intersection incidence and DD between both groups (P < .0001 and P = .0003, respectively).

CONCLUSIONS

The transtibial lateral approach for PCL reconstruction was a safer method than the medial approach regarding popliteal artery injury by a guidewire.

CLINICAL RELEVANCE

This study presents a slight modification of the most frequently used PCL reconstruction technique, intending to minimize guidewire injury to the popliteal artery.

Posterior cruciate ligament reconstruction by means of tibial tunnel: anatomical study on cadavers for tunnel positioning

OBJECTIVE

to determine the reference points for the exit of the tibial guidewire in relation to the posterior cortical bone of the tibia.

METHODS

sixteen knees from fresh cadavers were used for this study. Using a viewing device and a guide marked out in millimeters, three guidewires were passed through the tibia at 0, 10 and 15 mm distally in relation to the posterior crest of the tibia. Dissections were performed and the region of the center of the tibial insertion of the posterior cruciate ligament (PCL) was determined in each knee. The distances between the center of the tibial insertion of the PCL and the posterior tibial border (CB) and between the center of the tibial insertion of the PCL and wires 1, 2 and 3 (CW1, CW2 and CW3) were measured.

RESULTS

in the dissected knees, we found the center of the tibial insertion of the PCL at 1.09 ± 0.06 cm from the posterior tibial border. The distances between the wires 1, 2 and 3 and the center of the tibial insertion of the PCL were respectively 1.01 ± 0.08, 0.09 ± 0.05 and 0.5 ± 0.05 cm.

CONCLUSION

the guidewire exit point 10 mm distal in relation to the posterior crest of the tibia was the best position for attempting to reproduce the anatomical center of the PCL.

Neural Structures within Human Meniscofemoral Ligaments: A Cadaveric Study

Aim. To investigate the existence of neural structures within the meniscofemoral ligaments (MFLs) of the human knee. Methods. The MFLs from 8 human cadaveric knees were harvested. 5 μm sections were H&E-stained and examined under light microscopy. The harvested ligaments were then stained using an S100 monoclonal antibody utilising the ABC technique to detect neural components. Further examination was performed on 60-80 nm sections under electron microscopy. Results. Of the 8 knees, 6 were suitable for examination. From these both MFLs existed in 3, only anterior MFLs were present in 2, and an isolated posterior MFL existed in 1. Out of the 9 MFLs, 4 demonstrated neural structures on light and electron microscopy and this was confirmed with S100 staining. The ultrastructure of these neural components was morphologically similar to mechanoreceptors. Conclusion. Neural structures are present in MFLs near to their meniscal attachments. It is likely that the meniscofemoral ligaments contribute not only as passive secondary restraints to posterior draw but more importantly to proprioception and may therefore play an active role in providing a neurosensory feedback loop. This may be particularly important when the primary restraint has reduced function as in the posterior cruciate ligament-deficient human knee.