Abnormal femoral trochlea morphology is a risk factor for secondary injury of anterior cruciate ligament after reconstruction.

Secondary injury of the anterior cruciate ligament (ACL) is a common concern after anterior cruciate ligament (ACL) reconstruction, and identification of morphological risk factors is essential to prevent these injuries. We hypothesized that abnormal femoral trochlea morphology is associated with secondary ACL injuries after reconstruction. This study aimed to investigate the relationship between femoral trochlear morphology and secondary ACL injuries after reconstruction. A retrospective analysis was conducted on 20 patients who experienced secondary ACL injuries after reconstruction in our hospital between 2017 and 2022 (experimental group), and 40 patients were included in the control group. The following femoral trochlear characteristics were compared between the 2 groups: medial condylar height (MCH), trochlear sulcus height (TSH), lateral condylar height (LCH), trochlear sulcus depth (TSD), trochlear sulcus angle (TSA), medial trochlear inclination (MTI), and lateral trochlear inclination (LTI). The study found that patients in the secondary ACL injury after reconstruction group exhibited the following differences when compared to the control group: decreased MCH (56.33 ±â€…3.52 vs 59.93 ±â€…3.24, P value = .015), decreased TSD (4.89 ±â€…1.56 vs 6.98 ±â€…1.23, P value ˂ .001), decreased MTI (12.54 ±â€…6.57 vs 19.45 ±â€…6.35, P value ˂ .001), and increased TSA (145.23 ±â€…9.76 vs 139.25 ±â€…8.42, P value ˂ .001). This study demonstrated a significant correlation between abnormal femoral trochlear morphological characteristics and secondary ACL injuries after reconstruction. Decreased MCH, TSD, and MTI along with increased TSA are associated with a higher risk of secondary ACL injury. These data could thus help identify individuals susceptible to secondary ACL injuries after reconstruction.

Anatomic and radiological study on posterior pedicle screw fixation in the atlantoaxial vertebrae of children.

OBJECTIVE: To investigate the feasibility of posterior fixation with 3.5-mm pedicle screws in the atlantoaxial vertebrae of children. METHODS: In this study, atlantoaxial vertebrae specimens were obtained from 10 cadavers of children aged 6-8 years. We measured the height and width of the C(1) pedicle and the midportion of C(1) lateral mass; the width of C(1) posterior arch under the vertebral artery groove and the height of the external and internal one-third of this part; the external, internal height and the superior, middle, inferior width of the C(2) pedicle (transverse foramen). Furthermore, computed tomography (CT) axial scan was performed on 20 age-matched volunteers to obtain relative data of their atlantoaxial vertebrae. We measured the length and width of the C(1) and C(2) pedicles in the atlantoaxial cross-sectional plane. On CT workstation, we also measured the angles between the longitudinal axes of the atlantoaxial pedicles and the midsagittal plane. RESULTS: For the cadaveric specimen group, the height and width of the C1 pedicle were (5.26+/-0.44) mm and (6.26+/-0.75) mm respectively. The height of the medial one-third of the C1 posterior arch under the vertebral artery groove was (4.07+/-0.24) mm. The external, internal height and superior, middle, inferior width of the C2 pedicle was (6.86+/-0.48) mm, (6.67+/-0.49) mm, (6.63+/-0.61) mm, (5.41+/-0.39) mm and (3.71+/-0.30) mm, respectively. For the volunteer group measured by CT scan, the height and width of the C(1) pedicle were (5.47+/-0.34) mm and (6.63+/-0.54) mm respectively, while (6.59+/-0.51) mm and (5.13+/-0.42) mm of the C2 pedicle. The angles between the atlas, axis pedicles and the midsagittal plane were (9.60+/-1.32) degree and (27.80+/-2.22) degree respectively. CONCLUSION: It is feasible to place a 3.5-mm pedicle screw in the C(1) and C(2) pedicles of children aged 6-8 years old.