Widening of the popliteal hiatus on magnetic resonance imaging leads to recurrent subluxation of the lateral meniscus.

PURPOSE: This study was undertaken to elucidate the clinical significance of widening of the popliteal hiatus on magnetic resonance imaging (MRI), and to document the clinical results and technical aspects of arthroscopic repair of this finding. METHODS: Included are 82 knees after arthroscopic surgery, divided according to arthroscopic diagnosis into group A, hypermobility of lateral meniscus, 8 knees; group B, tear of the anterior horn of the lateral meniscus, 32 knees; and group C, no abnormality of the lateral meniscus, 36 knees with medial meniscal tears and 6 with other conditions. Popliteal hiatus diameter was measured and the popliteal hiatus/lateral tibial plateau (LTP) ratio was calculated on preoperative sagittal and coronal MRI. At arthroscopy, the widened popliteal hiatus in group A was tightened anteriorly by outside-in or all-inside suture and posteriorly with all-inside suture. Outcomes were evaluated with MRI, Lysholm, Tegner and VAS scores. RESULTS: The preoperative diameter of the popliteal hiatus and the popliteal hiatus/LTP ratio were significantly larger in group A than in groups B and C (p < 0.05) on both views. Threshold popliteal hiatus/LTP values of 0.16 and 0.18 on the sagittal and coronal views demonstrated diagnostic discrimination, and these values were significantly reduced after arthroscopy in Group A. Lysholm and Tegner scores were improved after tightening of the popliteal hiatus, while VAS scores reduced (all p < 0.05). CONCLUSION: Widening of the popliteal hiatus on MRI may lead to recurrent subluxation of the lateral meniscus. Arthroscopic anterior and posterior tightening of the popliteal hiatus was a safe and effective treatment. LEVEL OF EVIDENCE: II.

Improving the repair mechanism and miRNA expression profile of tibial defect in rats based on silent information regulator 7 protein analysis of mesenchymal stem cells.

The aim of this study was to verify the role of Silent Information Regulator 7 (SIRT7) in improving the repair mechanism of bone marrow mesenchymal stem cells (BMMSCs) and the expression of microribonucleic acid (miRNA). Human BMMSCs were extracted from patients with femoral fractures, and the proliferation activity of human BMMSCs before and after knockout SIRT7 and the expression levels of bone-related genes and proteins were compared. Thirty-two 8-week-old male Sprague-Dawley (SD) rats were randomly divided into a blank group, a chitosan scaffold group, a control group, and a silence information regulator knockout group 7 (n = 8). In addition to the blank group, the chitosan scaffold, the green fluorescent protein (GFP) transfected stem cell composite chitosan scaffold, and the SIRT7 knockout stem cell composite chitosan scaffold were implanted in the other three groups, respectively. The X-rays and small animal in vivo three-dimensional tomography (Micro-CT) were adopted to quantitatively analyze the volume fraction, the number of trabeculae, and the connection density. Compared with the other three groups, the bone defect was formed more in the medullary mesenchymal stem cell knockout group, and the bone volume fraction, number of trabeculae and connection density were significantly increased (P < 0.05). MiR-98-5p can significantly promote the formation of bone molecules and bone structure in rats (P < 0.05). Human BMMSCs combined with chitosan scaffold can accelerate the repair of tibial defects. MiR-98-5p targeting and regulating bone formation gene (CKIP-1) could significantly improve the process of osteogenesis in rats.

[Combined operation involving tibial tubercle distalization for recurrent patellar dislocation with patella alta].

Objective: To explore the clinical effects of combined operation involving tibial tubercle distalization for the recurrent patellar dislocation with patella alta. Methods: Between April 2010 and May 2016, 14 cases of recurrent patellar dislocation with patella alta were treated with combined operation involving tibial tubercle distalization. There were 5 males and 9 females with an average age of 18.5 years (range, 13-26 years). The left knee was involved in 9 cases and the right knee in 5 cases. The patella had dislocated 3.3 times on average (range, 2-5 times). The interval between the first dislocation and admission was 19.7 months on average (range, 4-60 months), and the main symptoms were knee pain and limited knee movement. Preoperative X-ray films, CT, and MRI examinations of knee joint showed that the epiphyseal plate closed in all patients. Of all patients, 3 patients had avulsion fracture of the inner edge of patella, and 2 patients had free body in articular cavity. The tibial tuberosity-trochlear groove (TT-TG) distance, patellar-trochlear-groove distance, Caton-Deschamps index, knee range of motion (ROM), Lysholm score, International Knee Documentation Committee (IKDC) score, Kujala score, and Tegner score were compared pre- and post-operation. Results: All patients had primary wound healing. All patients were followed up 24-72 months with an average of 34.6 months. X-ray film and CT examination showed that the patellar dislocation was corrected and the osteotomy of the tibial tubercle healed with an average healing time of 3.8 months (range, 3-5 month). At 1 day and 1 year after operation, the TT-TG distance, patellar-trochlear-groove distance, and Caton-Deschamps index showed significant differences when compared with preoperative values ( P<0.05), but there was no significant difference between 1 day and 1 year after operation ( P>0.05). At the 1 year and 2 years after operation, the knee ROM, Lysholm score, IKDC score, Kujala score, and Tegner score showed significant differences when compared with preoperative values ( P<0.05), and there was no significant difference between the 1 year and 2 years after operation ( P>0.05). Conclusion: Combined operation involving tibial tubercle distalization is a safe and reliable method, which has satisfactory short-term effectiveness for the recurrent patellar dislocation with patella alta.

[Research progress in diagnosis and treatment of injury of the popliteal meniscal fiber bundle].

Popliteal meniscal fiber bundle injury is relatively infrequent in clinic, which can be either isolated or associated with anterior cruciate ligament rupture, lateral meniscus injury and so on. Popliteal meniscal fiber bundle injury often leads to instability of lateral meniscus. Because of the lack of specific symptoms and signs of injury, the imaging changes are subtle, and it is easy to miss diagnosis and misdiagnosis in clinical. Timely diagnosis and treatment are essential to prevent the chronic pain and instability of the knee joint. This paper summarizes the anatomical characteristics, biomechanics, injury mechanism, diagnostic points and surgical treatment of the popliteal meniscus fiber bundle injury, in order to guide the diagnosis and treatment of the injury of the popliteal meniscus fiber bundle in the clinical work.