Bone Tunnel Diameter Measured with CT after Anterior Cruciate Ligament Reconstruction Using Double-Bundle Auto-Hamstring Tendons: Clinical Implications

OBJECTIVE: To evaluate the correlation between bone tunnel diameter after anterior cruciate ligament (ACL) reconstruction measured by computed tomography (CT) using multiplanar reconstruction (MPR) and stability or clinical scores. MATERIALS AND METHODS: Forty-seven patients (41 men and 6 women, mean age: 34 years) who had undergone ACL reconstruction with the double bundle technique using auto-hamstring graft and had subsequently received CT scans immediately after the surgery (T1: range, 1-4 days, mean, 2.5 days) and at a later time (T2: range, 297-644 days, mean, 410.4 days) were enrolled in this study. The diameter of each tunnel (two femoral and two tibial) at both T1 and T2 were independently measured using MPR technique by two radiologists. Stability and clinical scores were evaluated with a KT-2000 arthrometer, International Knee Documentation Committee objective scores, and the Lysholm score. Statistical analysis of the correlation between the diameter at T2 or the interval diameter change ratio ([T2 - T1] / T1) and clinical scores or stability was investigated. RESULTS: The tibial bone tunnels for the anteromedial bundles were significantly widened at T2 compared with T1 (observer 1, 0.578 mm to 0.698 mm, p value of 0.8) for both observers. Interobserver agreement for measurement was excellent (> 0.8) except for the most distal portion of the femoral bone tunnel for anterior medial bundle in immediate postoperative CT, which showed moderate agreement (concordance correlation coefficient = 0.6311). CONCLUSION: Neither the diameter nor its change ratio during interval follow-up is correlated with stability or clinical scores.

Effect of Antenatal Dexamethasone Treatment on Neuronal Morphogenesis

BACKGROUND: Glucocorticoids (GCs) are essential for normal development and the maturation of the central nervous system. The aim of this study was to determine the effects of antenatal dexamethasone (DEXA) treatment on neuronal morphogenesis and on the glial cell line-derived neurotrophic factor (GDNF) protein expression in neonatal rat. METHODS: Pregnant Sprague-Dawley rats were injected with saline (the control), or 0.2 mg/kg/day DEXA or 0.8 mg/kg/day DEXA at 17th, 18th and 19th day of gestation. The newborn rat brains were examined at postnatal days 1 (n=75) and 10 (n=78). RESULTS: The DEXA-treated groups showed distorted architectures of neurons in the cerebral cortex, hippocampus and cerebellar cortex at postnatal days 1 and 10 with an increased number of proliferating cell nuclear antigen (PCNA)-positive cells. The cerebellar cortex in the DEXA-treated groups showed delayed development with more PCNA-positive cells in the internal granular cell layer. The Purkinje cells showed a markedly decreased number and the decreased length of the dendritic processes. The GDNF positive reaction was decreased in the DEXA-treated groups in a dose-dependent manner. CONCLUSIONS: The developmental changes and neuronal degeneration at postnatal days 1 and 10 in the newborn rats that were exposed to DEXA at the late gestational age were associated with increased proliferative activity and a decreased level of GDNF protein expression.