Popliteal Artery Branching Variations: A Study on Multidetector CT Angiography

Popliteal artery branching variations on computed tomography angiography of 1542 lower limbs and its associated factors

BACKGROUND

The identification of popliteal artery branching variation is of anatomical importance for surgical and endovascular procedures in the posterior region of the knee and below.

PURPOSE

To evaluate the variations and associated factors of popliteal artery branching by computed tomography angiography (CTA).

MATERIAL AND METHODS

CTA of the lower extremities of 1542 lower limbs in 771 patients (513 men and 258 women) were retrospectively reviewed to assess the popliteal artery branching patterns. The patient's sex, side of lower limbs, and population were recorded and evaluated for their association with popliteal artery branching patterns. P < 0.05 was considered to indicate statistical significance.

RESULTS

Variations in the branching of the popliteal artery were recorded in 9.3% of patients. The three most common variations were found to be hypoplastic-aplastic posterior tibial artery (PT) (3.6%), trifurcation (2.0%), and hypoplastic-aplastic anterior tibial artery (0.8%). A new pattern was detected in 2 (0.1%) cases, which were described as double PTs. Statistically significant differences were noted in the proportion of variation branching between the male and female groups (odds ratio = 1.52; 95% confidence interval = 1.07-2.16; P = 0.02).

CONCLUSION

The findings on popliteal variational branching patterns in the present study were in conformance to previous reports. Our study identified a novel variation of popliteal artery branching, which has not been mentioned in the literature so far. Sex was found to be an associated factor of branching variation.

Analysis of the running position of the popliteal artery and branching level of the anterior tibial artery detected by magnetic resonance imaging to avoid vessel injury during surgery around the knee joint

Background

Vessel injuries during total knee arthroplasty or high tibial osteotomy are rare but have serious complications. This study aimed to analyze the running position of the popliteal artery (PA) and branching level of the anterior tibial artery (ATA), using magnetic resonance imaging (MRI). This analysis might be helpful in avoiding unnecessary vessel injury.

Methods

In total, 105 patients (41 men and 64 women), whose running position of the PA and branching level of the ATA could be detected by preoperative MRI, were included in this study. We configured zones A, B, C, and D to be 5–10, 15–20, 25–30 and 35–40 mm distal from the lateral tibial plateau in the axial view, respectively. First, the distance between the posterior cortex of the tibia and anterior border of the PA was measured. Second, the PA position from the medial border of the tibia was measured. This measured value was divided by the transverse diameter of the tibia, and multiplied by 100 to obtain the PA position from the medial border of the tibia. Third, the branching level of ATA was measured from the joint line. Subsequently, each value was compared between men (the M group) and women (the W group).

Results

The distance between the posterior cortex of the tibia and the anterior border of the PA was 5.5 ± 1.9, 10.4 ± 2.4, 12.5 ± 2.3 and 12.5 ± 2.3 (mm; mean ± SD) in zones A, B, C, and D, respectively. Comparing both groups, this distance was significantly larger (more separated posteriorly) in zones C and D in the M group. The PA position from the medial border of the tibia was 51.7 ± 6.5, 52.7 ± 8.2, 56.7 ± 10.5 and 66.8 ± 14 (%; mean ± SD) in zones A, B, C, and D, respectively. On comparing the two groups, this position was significantly larger (more laterally shifted) in zone D in the W group. The branching level of the ATA was not detected within 40 mm distal to the joint line in 92 patients (87.6%). However, it was detected within 40 mm (mean 32.5 mm; range 20–38) in 12 patients (11.4%). Among them, 11 were women. Only one woman had an aberrant branching pattern: the ATA bifurcated at the joint level.

Conclusion

The PA positioned closest at the joint level, gradually separated and shifted laterally towards the distal side. The distance between the posterior cortex of the tibia and the anterior border of the PA was closer in women than in men in zones C and D. Although a difference of 2 mm is small, the risk of PA injury can be considered to be higher in women than in men. Furthermore, ATA injury is also a concern during retraction of the tibialis anterior muscle posteriorly, and the descending cut of the tibial tuberosity, particularly in women.

Efficacy of posterior capsular release for flexion contracture in posterior-stabilized total knee arthroplasty

Purpose

Posterior capsular contracture causes stiffness during knee extension in knee osteoarthritis. Furthermore, in posterior-stabilized total knee arthroplasty (PS-TKA), a unique design such as the cam mechanism could conflict with the posterior capsule (PC) causing flexion contracture (FC). However, few studies have focused on the anatomical aspects of the PC. This study aimed to investigate the anatomical site and forms of posterior capsular attachment to the femoral cortex, and to evaluate the efficacy of posterior capsular release for FC by assessing changes in knee extension angles using a navigation system.

Methods

Attachment sites of the PC were investigated in 10 cadaveric knees using computed tomography. PS-TKA was performed in six cadaveric knees using a navigation system to evaluate the efficacy of posterior capsular release for FC. Posterior capsular release was performed stepwise at each part of the femoral condyle.

Results

The gastrocnemius tendon and PC were integrally attached to the femoral cortex at the medial and lateral condyles, whereas the PC at the intercondylar fossa was independently attached directly to the femoral cortex. Moreover, the PC at the intercondylar fossa was attached most distally among each femoral condyle. Posterior capsular release at the intercondylar fossa allowed 11.4° ± 2.8° improvement in knee extension. This angle was further improved by 5.5° ± 1.3°, after subsequent capsular release at the medial and lateral condyles.

Conclusion

The forms and sites of posterior capsular attachment differed based on the part of the femoral condyle. Stepwise posterior capsular release was effective for FC in PS-TKA.

Level of evidence

III.

Prevalence and characteristics of the aberrant anterior tibial artery: a single-center magnetic resonance imaging study and scoping review

Background

Planning surgical procedures of the lower leg benefits from considering the possibility of an aberrant anterior tibial artery (AATA), but previously published data on the frequency of this anatomic variant shows heterogeneity. We assessed the prevalence of AATA in a Latin American cohort using magnetic resonance imaging (MRI) and compared these with other studies reported in the literature.

Methods

We retrospectively included consecutive patients who had undergone multiplanar knee MRI at a radiology department in Lima, Peru. The MRI protocol included coronal T1 weighted, axial, sagittal and coronal proton density fat-saturated (PDFS) and sagittal T2 weighted images.

Two experienced radiologists assessed all images and were blinded to each other’s findings. The frequency of the AATA was compared to previous cohorts. A scoping review was undertaken to provide an overview of previously published data on the prevalence of ATAA.

Results

We analyzed 280 knee MRI examinations of 253 patients (median age 41 years (IQR 31–52), 53.8% male). The aberrant anterior tibial artery variant was present in 8 of 280 (2.9%) evaluated knees, resulting in a prevalence of 3.2% in our study population. The PDFS sequence in the axial or sagittal orientation was most effective to identify AATA. The frequency of AATA in the reviewed literature using different radiological modalities ranged from 0.4 to 6% (median 1%, IQR (0.5–2.3%).

Conclusions

The AATA is a frequent vascular variant that can be detected by MRI in the preparation of invasive interventions of the lower leg.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04801-9.

The congenital popliteal vasculature patterns in fibular free flap reconstruction by means of surgical anatomy in cadavers

Fibular free flap (FFF) is frequently used for reconstruction requiring vascularized bone. Thus, understanding its vasculature variation is crucial. This study investigates the popliteal artery branching variations in Thai cadavers and compares them with previous studies. One hundred and sixty-two legs from 81 formalin-embalmed cadavers were dissected. The popliteal artery branching patterns were classified. The previous data retrieved from cadaveric and angiographic studies were also collected and compared with the current study. The most common pattern is type I-A (90.7%). For the variants, type III-A was the majority among variants (6.2%). Type IV-A, hypoplastic peroneal artery, was found in one limb. A symmetrical branching pattern was found in 74 cadavers. Compared with cadaveric studies, type III-B and III-C are significantly common in angiographic studies (p = 0.015 and p = 0.009, respectively). Type I-A is most common according to previous studies. Apart from this, the prevalence of type III-A variant was higher than in previous studies. Furthermore, type III-B and III-C are more frequent in angiographic studies which might be from atherosclerosis. Thus, if the pre-operative CTA policy is not mandatory, the patients at risk for atherosclerosis and population with high variants prevalence should undergo pre-operative CTA with cost-effectiveness consideration.