Comparison of Habitual Versus Recurrent Patellar Dislocation in Children and Adolescents: Differences in Radiological Features.

Background: Recurrent patellar dislocation (RPD) and habitual patellar dislocation (HPD) in flexion are frequently encountered in children and adolescents. Purpose: To compare the radiological features of RPD and HPD in children and adolescents. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Imaging data were collected from patients aged 9 to 15 years who received surgical treatment for HPD or RPD at a single institution between June 2015 and September 2020. The prevalence of trochlear dysplasia, tibial tubercle lateralization, and lower limb rotational deformity was assessed through hip/knee/ankle computed tomography (CT) using the following quantitative indicators: trochlear depth index, lateral trochlear inclination, sulcus angle, tibial tubercle-trochlear groove (TT-TG) distance, ratio of TT-TG distance to femoral width, TT-TG angle, femoral anteversion angle, and tibial external rotation angle. The morphology of trochlea and patella were graded on knee CT using the Dejour and Wiberg classification. The Insall-Salvati index and Caton-Deschamps index were used to evaluate the height of the patella on lateral view radiographs. To evaluate lower limbs malalignment, the mechanical lateral distal femoral angle and medial proximal tibial angle were measured on weightbearing full-length radiographs. The collected data were analyzed and compared between the HPD and RPD groups. Results: Enrolled were 15 patients (21 knees) diagnosed with HPD and 18 patients (22 knees) diagnosed with RPD. The age of first dislocation was significantly younger in the HPD group (7.6 ± 3.4 vs 11.2 ± 1.4 years; P = 0.003). Knees in the HPD group had a significantly higher proportion of Dejour type C dysplasia (57.1% vs 4.5%; P < .005) and Wiberg type 3 patella (66.7% vs 9.1%; P < .001). There were statistically significant differences between the groups in the trochlear depth index (HPD vs RPD: 1.1 ± 1.7 vs 2.2 ± 1.5 mm; P = .039), sulcus angle (170.3° ± 13.7° vs 157.3° ± 16.0°; P = .007), Insall-Salvati index (1.1 ± 0.2 vs 1.3 ± 0.2; P = .034), and tibial external rotation angle (31.3° ± 7.8° vs 38.4° ± 8.5°; P = .009). Conclusion: Patients in the HPD group presented with poorer trochlear and patellar development, lower patellar height, and less tibial external rotation compared with patients in the RPG group.

A Single Approach to Arthroscopic Reduction and Debridement for Developmental Dislocation of the Hip in 12 Infants.

BACKGROUND Developmental dislocation of the hip (DDH) results in osteoarthritis in infants and children. This study aimed to investigate the effects of a single approach to arthroscopic reduction and debridement on clinical outcome in 12 infants with DDH. MATERIAL AND METHODS Twelve infants with irreducible DDH underwent single approach arthroscopic reduction and debridement followed by the use of a frog-leg position plaster cast with fixed flexion and abduction of the hips combined with external fixation for 6-8 weeks. Magnetic resonance imaging (MRI) or plain X-ray images were analyzed. Intra-articular obstructive factors for reduction were evaluated. The safety angle, medialization rate of the femoral head, and the acetabular angle were measured before and after arthroscopic reduction. RESULTS Imaging showed that the signs of DDH were significantly improved following arthroscopic reduction. Obstructive factors included hypertrophy of the round ligament, fibrous tissue and fat in the acetabular base, arthrocapsular constriction, and varus deformity of the hip. The safety angle was significantly increased following arthroscopic reduction (53.5°) compared with the safety angle before treatment (18.5°) (p<0.05). Medialization of the femoral head was significantly increased (127%) compared with that before treatment (72%) (p<0.05). Arthroscopic reduction significantly reduced the acetabular angle (25°) compared with that before treatment (37.5°) (p<0.05). CONCLUSIONS Single approach arthroscopic reduction and debridement was an effective method for treating DDH that significantly improved the medialization rate of the femoral head, acetabular angle, and the outcome of external fixation when a plaster cast was used with fixed flexion and abduction of the hips.

Treatment of Post-traumatic Pediatric Ankle Varus Deformity with Physeal Bar Resection and Hemi-Epiphysiodesis.

Children presenting with partial physeal arrest and significant remaining growth may benefit from physeal bar resection, although the operation is a technique demanding procedure. This study evaluates the treatment of post-traumatic pediatric ankle varus deformity using physeal bar resection and hemi-epiphysiodesis with the assistance of two operative methods. Forty-five patients presenting with a distal tibial medial physeal bridge as well as ankle varus deformity following traumatic ankle physeal injury between 2009 and 2017 were followed. These patients were treated with physeal bar resection and hemi-epiphysiodesis, with the assistance of either fluoroscopy (10 cases) or intraoperative three-dimensional navigation (35 cases). Of the 45 cases, the median age was 9.0 years (range: 3-14 years) with 28 male and 17 female patients. The median of pre-operation ankle varus angle was 20 degrees (IQR 15-25) and 5 degrees (IQR 0-20) at the time of final follow up, representing a statistically significant difference (P<0.05). No differences were observed with regards to age, gender, and surgical history between effective group and ineffective group (P>0.05). The median of pre-operative ankle varus angles of the navigation and fluoroscopy groups were both 20 degrees (P>0.05). The median correction angle of the navigation and fluoroscopy groups was 10 and 15 degrees, respectively (P>0.05). Our results indicate that physeal bar resection and hemiepiphysiodesis are effective treatments for correcting ankle varus deformity due to traumatic medial physeal arrest of the distal tibia. We observe no difference in outcome between fluoroscopy group and three-dimensional navigation group during the procedures.