Gherardo Pagliazzi1,2, Jutta M Ellermann3, Cathy S Carlson3, Kevin G Shea4, Elizabeth A Arendt3. 1. Rizzoli Orthopaedic Institute, Bologna, Italy. 2. Lugano Regional Hospital, Lugano, Switzerland. 3. Department of Orthopedic Surgery, University of Minnesota, Minneapolis, Minnesota, USA. 4. Department of Orthopaedic Surgery, Stanford University, Stanford, California, USA.
Abstract
BACKGROUND: Understanding the morphology of cartilage/bony maturation in preadolescents may help explain adult trochlear variation. PURPOSE: To study trochlear morphology during maturation in children and infants using magnetic resonance imaging (MRI). STUDY DESIGN: Descriptive laboratory study. METHODS: Twenty-four pediatric cadaveric knees (10 male and 14 female knees; age, 1 month to 10 years) were included. High-resolution imaging of the distal femoral secondary ossification center was performed using 7-T or 9.4-T MRI scanners. Three-dimensional MRI scans were produced, and images were reformatted; 3 slices in the axial, sagittal, and coronal planes images were analyzed, with coronal and sagittal imaging used for image orientation. Biometric analysis included lateral and medial trochlear height (TH); cartilaginous sulcus angle (CSA); osseous sulcus angle (OSA); trochlear depth; and trochlear facet (TF) length symmetry. Sex comparisons were considered when ≥1 specimen from both sexes of the same age was available; these included 11 knees spanning 4 age groups (ages 1, 3, 4, and 7 years). RESULTS: The analysis of trochlear morphology showed a lateral TH greater than the medial TH at all ages. The thickest cartilage was found on the lateral TF in the younger specimens. Regarding the development of osseous and cartilaginous trochlear contour, a cartilaginous sulcus was present in the 3-month-old specimen and continued to deepen up to the age of 4 years. The shape of the osseous center evolved from round (1 month) to oval (9 months) to rectangular (2 years); no distinct bony trochlear sulcus was present, although a well-formed cartilaginous sulcus was present. The first evidence of formation of a bony sulcus was at 4 years. By the age of 7 to 8 years, the bony contour of the adult distal femur resembled its cartilaginous contour. Female samples had a shallower CSA and OSA than did the male ones in all samples that had a defined OSA. CONCLUSION: Female trochlear grooves tended to be shallower (flatter). The lateral trochlea was higher (TH) and wider (TF length) during growth than was the medial trochlea in both sexes; furthermore, the development of the osseous sulcus shape lagged behind the development of the cartilaginous sulcus shape in the authors' study population. CLINICAL RELEVANCE: Bony anatomy of the trochlear groove did not match the cartilaginous anatomy in preadolescent children, suggesting that caution should be used when interpreting bony anatomy in this age group.
BACKGROUND: Understanding the morphology of cartilage/bony maturation in preadolescents may help explain adult trochlear variation. PURPOSE: To study trochlear morphology during maturation in children and infants using magnetic resonance imaging (MRI). STUDY DESIGN: Descriptive laboratory study. METHODS: Twenty-four pediatric cadaveric knees (10 male and 14 female knees; age, 1 month to 10 years) were included. High-resolution imaging of the distal femoral secondary ossification center was performed using 7-T or 9.4-T MRI scanners. Three-dimensional MRI scans were produced, and images were reformatted; 3 slices in the axial, sagittal, and coronal planes images were analyzed, with coronal and sagittal imaging used for image orientation. Biometric analysis included lateral and medial trochlear height (TH); cartilaginous sulcus angle (CSA); osseous sulcus angle (OSA); trochlear depth; and trochlear facet (TF) length symmetry. Sex comparisons were considered when ≥1 specimen from both sexes of the same age was available; these included 11 knees spanning 4 age groups (ages 1, 3, 4, and 7 years). RESULTS: The analysis of trochlear morphology showed a lateral TH greater than the medial TH at all ages. The thickest cartilage was found on the lateral TF in the younger specimens. Regarding the development of osseous and cartilaginous trochlear contour, a cartilaginous sulcus was present in the 3-month-old specimen and continued to deepen up to the age of 4 years. The shape of the osseous center evolved from round (1 month) to oval (9 months) to rectangular (2 years); no distinct bony trochlear sulcus was present, although a well-formed cartilaginous sulcus was present. The first evidence of formation of a bony sulcus was at 4 years. By the age of 7 to 8 years, the bony contour of the adult distal femur resembled its cartilaginous contour. Female samples had a shallower CSA and OSA than did the male ones in all samples that had a defined OSA. CONCLUSION: Female trochlear grooves tended to be shallower (flatter). The lateral trochlea was higher (TH) and wider (TF length) during growth than was the medial trochlea in both sexes; furthermore, the development of the osseous sulcus shape lagged behind the development of the cartilaginous sulcus shape in the authors' study population. CLINICAL RELEVANCE: Bony anatomy of the trochlear groove did not match the cartilaginous anatomy in preadolescent children, suggesting that caution should be used when interpreting bony anatomy in this age group.
Authors: Connor G Richmond; Kevin G Shea; Jessica F Burlile; Ann M Heyer; Henry B Ellis; Philip L Wilson; Elizabeth A Arendt; Marc A Tompkins Journal: J Pediatr Orthop Date: 2020-02 Impact factor: 2.324
Authors: Jutta M Ellermann; Kai D Ludwig; Mikko J Nissi; Casey P Johnson; John P Strupp; Luning Wang; Štefan Zbýň; Ferenc Tóth; Elizabeth Arendt; Marc Tompkins; Kevin Shea; Cathy S Carlson Journal: JB JS Open Access Date: 2019-12-05