Ulnar shortening osteotomy for posttraumatic ulnar impaction syndrome in adolescent (younger than 18 years) - Based on the Cha & Shin assessment.

PURPOSE: We performed ordinary ulnar shortening osteotomy (USO) in patients younger than 18 years old with secondary ulnar impaction syndrome (UIS) after traumatic events. Here, we report the clinical and radiologic outcomes with a review of the previous literature through a retrospective case series. METHODS: Twenty-two adolescents treated by USOs from 2006 to 2018 were investigated. The amount of shortening was classified into three categories. The first category was for a still open physis on the medial half of the radius in those younger than 15. In this category, we osteotomized the ulna for the physis level to be left neutral or negative by 1-2 mm. The second category had no growth potency in the radius. If the patient was younger than 15, we considered only residual growth of the ulna, thus performing USO for the ordinary UV to be negative by 2-3 mm. For patients aged 15-18 years old, if growth potency was nearly absent in the ulna, we performed traditional USO with a neutral ulnar variance (UV). RESULTS: Categories 1, 2, and 3 for the amount of USO were determined for 4, 4, and 14 patients, respectively. All USOs properly healed without substantial complications. The mean preoperative UV was 2.91 mm, and the final value decreased to 0.23 with statistical significance (p < 0.001). The range of wrist motion was improved after USO from 133.86° and 132.73° to 154.77° and 160.68° (all, p < 0.001 in flexion-extension and pronation-supination arcs, respectively). The preoperative VAS and MMWS scores also improved from 2.77 to 75.00 to 0.18 and 88.86, respectively, at the final follow-up (all, p < 0.001). CONCLUSIONS: UIS in adolescent populations after trauma in their children/younger adolescents could be properly treated by USO. Even with an open physis at the ulna, neutral UVs could be achieved, and the clinical outcomes were satisfactory. However, long-term follow-up is still needed regarding TFCC and DRUJ status. LEVEL OF EVIDENCE: Level IV, retrospective case series.

MRI assessment of growth disturbances after ACL reconstruction in children with open growth plates-Prospective multicenter study of 100 patients.

INTRODUCTION: We were interested in the consequences of anterior cruciate ligament (ACL) reconstruction on the growth plates and the impact on growth in children with open growth plates. The primary objective was related to growth disturbances with the null hypothesis being that ACL reconstruction in open growth plates does not cause any. The secondary objective related to the presence of physis lesions on MRI, with the null hypothesis being that ACL reconstruction in open growth plates does not induce any. MATERIAL AND METHODS: In the context of a 2017 SFA symposium on ACL reconstruction with open growth plates, we conducted a prospective multicenter study with 2 years' follow-up. The study enrolled 100 patients; 71 were available for analysis. Four reconstruction techniques were used: semitendinosus-gracilis (STG), short graft (SG), quadriceps tendon (QT) and fascia lata (FL). MRI was used to look for growth disturbances as evidenced by deviation of the Harris lines or modification of the physis and diaphysis angles. Physis lesions were determined on MRI based on the presence of physeal bone bridges (PBB). RESULTS: No growth disturbances were found. However, PBBs were found in 14 patients (20%). At the femur, the relative risk (RR) was higher when a STG graft was used (RR=2.1) and the tunnel diameter was≥9mm (RR=1.7). Epiphyseal fixation had a higher risk than transphyseal fixation (RR=1.6 vs. 1.2). At the tibia, the RR was higher when a QT graft was used (RR=3.6), when screw fixation was performed (RR=3.7) or when the graft did not fill the tunnel sufficiently (RR=1.5). DISCUSSION: The absence of growth disturbances after 2 years' follow-up validates the possibility of ACL reconstruction with open growth plates, including with transphyseal techniques. The presence of small growth plate lesions such as bone bridges means that precautions should be taken with respect to tunnel trajectory, tunnel diameter, graft and tunnel diameter matching and graft fixation. LEVEL OF EVIDENCE: III, prospective cohort study.

Assessment of pharmacokinetics for microvessel proliferation by DCE-MRI for early detection of physeal bone bridge formation in an animal model.

OBJECTIVES: Bone bridge formation occurs after physeal lesions and can lead to growth arrest if not reversed. Previous investigations on the underlying mechanisms of this formation used histological methods. Therefore, this study aimed to apply a minimally invasive method using dynamic contrast-enhanced MRI (DCE-MRI). MATERIALS AND METHODS: Changes in functional parameters related to the microvessel system were assessed in a longitudinal study of a cohort of an animal model applying a reference region model. The development of morphology of the injured physis was investigated with 3D high-resolution MRI. To acquire complementary information for MRI-related findings qRT-PCR and immunohistochemical data were acquired for a second cohort of the animal model. RESULTS: The evaluation of the pharmacokinetic parameters showed a first rise of the transfer coefficient 7 days post-lesion and a maximum 42 days after operation. The analysis of the complementary data showed a connection of the first rise to microvessel proliferation while the maximum value was linked to bone remodeling. CONCLUSION: The pharmacokinetic analysis of DCE-MRI provides information on a proliferation of microvessels during the healing process as a sign for bone bridge formation. Thereby, DCE-MRI could identify details, which up to now required analyses of highly invasive methods.