Kengo Shimozaki

Histopathological study of the infrapatellar fat pad in the rat model of patellar tendinopathy: A basic study

BACKGROUND Patellar tendinopathy is difficult to successfully treat. This study aimed to characterize the pathological changes of the infrapatellar fat pad (IPFP) in patellar tendinopathy (PT), and to investigate the influence of PT on the development of fibrotic changes in the IPFP. METHODS Forty male Wistar rats were randomly divided into PT (n = 20) and control groups (n = 20). Bacterial collagenase I (patellar tendinopathy group) or saline (control) was injected, intratendinous, into the patellar tendon. Rats were sacrificed at week 12. The whole knee joint was sagittally sectioned and stained with hematoxylin-eosin and Massons trichrome. The IPFP samples were graded according to cellularity, fibrosis, and vascularity. The whole IPFP and blue-stained area was measured. Mann-Whitney U tests were used to compare the between-group differences of each score and quantitative value. RESULTS Scores for cellularity were three (2-3) and 0 (0-1) in the PT and control groups, respectively (P < 0.01). Mean scores for fibrosis were two (1-3) and 0 (0-1) in the PT and control groups, respectively (P < 0.01). Mean scores for vascularity were two (2-3) and one (1-1) in the PT and control groups, respectively (P < 0.01). There was a significant difference in the total score between the PT and control groups (seven (5-8) and two (1-3), respectively) (P < 0.01). Average percentages of the fibrous area of the IPFP were 38.2 ± 26.5% and 11.2 ± 3.9% in the patellar tendinopathy and control groups, respectively (P < 0.01). CONCLUSION The IPFP in the patellar tendinopathy group showed greater cellularity, fibrosis, and vascularity than the control group.

Thoracic spondylolisthesis and spinal cord compression in diffuse idiopathic skeletal hyperostosis: a case report

BackgroundDiffuse idiopathic skeletal hyperostosis has long been regarded as a benign asymptomatic clinical entity with an innocuous clinical course. Neurological complications are rare in diffuse idiopathic skeletal hyperostosis. However, if they do occur, the consequences are often significant enough to warrant major neurosurgical intervention. Neurological complications occur when the pathological process of ossification in diffuse idiopathic skeletal hyperostosis extends to other vertebral ligaments, causing ossification of the posterior longitudinal ligaments and/or ossification of the ligamentum flavum. Thoracic spondylolisthesis with spinal cord compression in diffuse idiopathic skeletal hyperostosis has not previously been reported in the literature.Case presentationA 78-year-old Japanese man presented with a 6-month history of gait disturbance. A magnetic resonance imaging scan of his cervical and thoracic spine revealed anterior spondylolisthesis and severe cord compression at T3 to T4 and T10 to T11, as well as high signal intensity in a T2-weighted image at T10/11. Computed tomography revealed diffuse idiopathic skeletal hyperostosis at T4 to T10. He underwent partial laminectomy of T10 and posterior fusion of T9 to T12. The postoperative magnetic resonance imaging revealed resolution of the spinal cord compression and an improvement in the high signal intensity on the T2-weighted image.ConclusionsWe report the first case of thoracic spondylolisthesis and spinal cord compression in diffuse idiopathic skeletal hyperostosis. Neurosurgical intervention resulted in a significant improvement of our patient’s neurological symptoms.

Ipsilateral Medial and Lateral Discoid Meniscus with Medial Meniscus Tear

Introduction: Discoid meniscus is a well-documented knee pathology, and there are many cases of medial or lateral discoid meniscus reported in the literature. However, ipsilateral concurrent medial and lateral discoid meniscus is very rare, and only a few cases have been reported. Herein, we report a case of concurrent medial and lateral discoid meniscus. Case Report: A 27-year-old Japanese man complained of pain on medial joint space in his right knee that was diagnosed as a complete medial and lateral discoid meniscus. In magnetic resonance imaging, although the lateral discoid meniscus had no tear, the medial discoid meniscus had a horizontal tear. Arthroscopic examination of his right knee similarly revealed that the medial discoid meniscus had a horizontal tear. In addition, the discoid medial meniscus also had an anomalous insertion to the anterior cruciate ligament, and there was also mild fibrillation of the medial tibial cartilage surface. We performed arthroscopic partial meniscectomy for the torn medial discoid meniscus but not for the asymptomatic lateral discoid meniscus. The latest follow-up at 18 months indicated satisfactory results. Conclusion: We report a rare case of ipsilateral medial and lateral discoid meniscus with medial meniscus tear. The medial discoid meniscus with tear was treated with partial meniscectomy, whereas the lateral discoid meniscus without tear was only followed up.