Ultrasonographic Assessment of the Normal Femoral Articular Cartilage of the Knee Joint: Comparison with 3D MRI

Objective. Ultrasonography (US) has a promising role in evaluating the knee joint, but capability to visualize the femoral articular cartilage needs systematic evaluation. We measured the extent of this acoustic window by comparing standardized US images with the corresponding MRI views of the femoral cartilage. Design. Ten healthy volunteers without knee pathology underwent systematic US and MRI evaluation of both knees. The femoral cartilage was assessed on the oblique transverse axial plane with US and with 3D MRI. The acoustic window on US was compared to the corresponding views of the femoral sulcus and both condyles on MRI. The mean imaging coverage of the femoral cartilage and the cartilage thickness measurements on US and MRI were compared. Results. Mean imaging coverage of the cartilage of the medial femoral condyle was 66% (range 54%–80%) and on the lateral femoral condyle 37% (range 25%–51%) compared with MRI. Mean cartilage thickness measurement in the femoral sulcus was 3.17 mm with US and 3.61 mm with MRI (14.0% difference). The corresponding measurements in the medial femoral condyle were 1.95 mm with US and 2.35 mm with MRI (21.0% difference), and in the lateral femoral condyle, they were 2.17 mm and 2.73 mm (25.6% difference), respectively. Conclusion. Two-thirds of the articular cartilage of the medial femoral condyle, and one-third in the lateral femoral condyle, can be assessed with US. The cartilage thickness measurements seem to be underestimated by US. These results show promise for the evaluation of the weight-bearing cartilage of the medial femoral condyle with US.

First-Time Acute Lateral Patellar Dislocation in Children and Adolescents: What About Unaffected Knee Patellofemoral Joint Anatomic Abnormalities?

Background and Objectives: Acute lateral patellar dislocation (LPD) is the most common acute knee disorder in children and adolescents, and may lead to functional disability. The purpose of this study was to identify key differences and correlations of the patellofemoral joint (PFJ) morphology between intact and contralateral injured knees in a first-time traumatic LPD population aged under 18 years. Materials and Methods: The data were gathered prospectively from a cohort of 58 patients (35 girls and 23 boys). The prevalence and combined prevalence of patella alta (PA) and trochlear dysplasia (TD) in both knees of patients were evaluated using X-ray by two radiologists. Results: The PFJ of patients’ intact knees had a lower rate of TD (1.72% vs. 5.2%) and a less common combination of PA with shallow femoral sulcus (SFS) (22.4% vs. 44.8%) but more frequent PA (62.1% vs. 41.4%) compared with their injured knees. We noted statistically significant positive correlations (SSPCs) between the femoral sulcus angle (FSA) and PA in patients with intact (r = 0.37; p < 0.005) and contralateral injured knees (r = 0.33; p < 0.05). Conclusion: There were SSPCs between the FSA and PA in both gender and age groups of patients with intact and contralateral injured knees. The SSPCs between the FSA and PA of intact knees were higher in the patients with a more dysplastic PFJ anatomy (PA and TD) of the injured knees as compared to patients with only PA of the injured knees.

PATELLAR FACET MORPHOLOGY IN EARLY PEDIATRIC DEVELOPMENT

Background: The relative influence of patella and trochlear shape on the development of each structure is poorly understood. Articular morphology is felt to be an important factor influencing patellar instability. The purpose of this study was to evaluate the development of patellar facets in relation to age and sulcus depth in the pediatric knee. Methods: Dissection of 57 immature knees (1 month – 11 years; 36 male) was performed by fellowship-trained orthopaedic surgeons. A coordinated laser scanner, and analysis software (Hexagon Romer V3 CMM; Polyworks) were used to record cartilage anatomy. Patellar facets were identified as distinct regions of surface contour. In a subset of 30 specimens (2 years – 11 years; 22 male) trochlear cartilage sulcus angles were analyzed at points on the trochlea in relation to orientation angle from the femoral axis [F90° (perpendicular to the femoral axis, correlated to the posterior condylar axial slice), F120° (30° flexion), and F150° (60° flexion)]. Spearman’s correlations and nonparametric Mann-Whitney tests were evaluated for specimen age, patellar articular surface lengths, and trochlear sulcus angles. Results: There was strong correlation of patellar facet development with the angle of the cartilaginous femoral sulcus at 30° of flexion (p<0.001, rs=-0.696). With deepening femoral sulcus angles (range 137°-163°), there was an increase in the number of patellar facets present. Additionally, the presence of multiple medial facets was correlated with the sulcus angle at 30° (p<0.01) (Fig. 1). In the 13 specimens with a sulcus angle < 150°, all demonstrated well-formed patella with 5-7 facets identified. Within the group including those specimens younger than 2 years old, age (p<0.001) and width of the patellar articular surface (p<0.001) were correlated with the number of facets present. Multiple facet development on the lateral side of the patella was most strongly correlated with patellar articular surface width (p<0.001). Gender and the superior-most sulcus angle (F90°) didn’t correlate with patellar morphological development. The average number of facets identified was 3.8 (+/- 1.6), and the median number present was 4 (range 0-7). The most common patellar shape was 5 facets (n=16, age range 3 months – 11 years); medial, inferior-medial, lateral, inferior-lateral, and odd. Conclusion: Complex patellar morphology with multiple facets present is not uncommon in early pediatric development, with patellar width and the femoral sulcus angle at 30° as correlates. Significance: Patellar maturation may occur early and further investigation of the relationship of patellofemoral dysplasia on the early development of the corresponding structures is warranted. [Figure: see text]

Developmental patello-femoral displasia (experimental study)

Similar to developmental hip dysplasia patella is an important factor for the development of femoral troclea. This study was performed in an attempt to evaluate the effect of patella on development of femoral trochlea. Thirty two 4 weeks old New Zeeland rabbits were used in this study. Patella of the left knee was dislocated and 4 weeks after, a new operation was performed to relocate the patella to its normal anatomical location (group 1, 16 rabbits). In the second 16 rabbits patella of the left knee was dislocated and no other surgical intervention was performed (group 2). All the non operated right knees were used as the control group (group 3). All the rabbits were sacrificed when they were 6 months old. Computed tomography (CT) was performed to measure femoral sulcus angle and femoral trochlear dept in every knee. Kolmogorov-Smirnov, Anova and Kruskal-Wallis tests were used to evaluate the results. Trochlear sulcus angle was measured as 127.7 degree in group 1, 133.85 degree in group 2 and 127.0 degree in control group. The depth of the trochlear grove is 1.41 mm, 1.15 mm and 1.26 mm respectively. Trochlear sulcus angle and depth that were measured in group 2 were statistically different from group 1 and control group (P<0.05). The most important finding of this study is insufficient development of trochlear sulcus in group 1 in which the patella was dislocated. Bone development is a complex procedure, mechanical stress has an important role on bone morphology. This study showed that patellar impulse is needed for a normal trochlear sulcus development. Similar to developmental hip dysplasia shallow trochlear sulcus due to insufficient patellar impulse can be named as “developmental patello-femoral dysplasia”. Malposition of patella on trochlear grove has an important role in patello-femoral pain syndrolme. Diagnosis and treatment of this malposition in early ages can reduce the incidence of patello-femoral pain syndrome and other patello-femoral abnormalities in adult age. This study demonstrated that, similar to developmental hip dysplasia, patello-femoral dysplasia must be diagnosed and treated in early ages to prevent anatomical abnormalities. [Figure: see text]

Evaluation of the activity of intraarticular hyaluronic acid in the repair of experimentally induced osteochondral defects of the stifle joint in dogs

The present study examined the results of using hyaluronic acid with autogenetic cancellous grafts in the treatment of experimentally induced osteochondral defects in the stifle joints of dogs. In this study, 10 mature dogs of different breeds, weights and of both sexes were used. General anesthesia and usual operation procedures were followed. A 10 mm deep defect was created on the femoral sulcus of the trochlea with a drill tip of 8 mm in diameter. The defects in the right and left legs were filled with autogenic cancellous grafts taken from the metaphysial region of the tibia. The left legs constituted the experimental group while the right legs served as control group. In the experimental group, 2 mg/kg intraarticular hyaluronic acid was twice administered into the stifle joint, i.e., immediately subsequent to the operation and 1 month afterwards. Parenteral antibiotics were prescribed postoperatively for ten days. Five animals were sacrificed at the third and sixth month after surgery. Macroscopic and microscopic findings obtained from each case were evaluated. On macroscopical examination, trochlear defects were determined to be incompletely filled at the third month in both control and experimental groups. On histopathologic examination, a loose fibrovascular formation in the area where the graft was applied was observed to be present in both control and experimental groups. However, in the experimental group this formation was more superficial, ossification activity was greater and trabeculous bone formation had been initiated. Macroscopical examination carried out in the sixth month determined that in the control group the defect surface did not fill up to the trochlear sulcus level. In the histopathologic examination, in control groups it was found that fibrocartilageous structures were developing in the fibrovascular space even though ossification was incomplete. The macroscopic examination showed that in the experimental group, the defect surface reached the trochlear sulcus level of defects in this month. The histopatologic examination revealed that fibrous tissue comprised a thin layer, under which ossification processes were complete and bone trabeculates fully formed. It was concluded that the usage of autogenic cancellous graft along with hyaluronic acid may be useful in the repair of large osteochondral defects.