ABSTRACT
Objective To explore the short-term results of arthroscopic medial retinaculum placation (MRP) and lateral retinaculum release (LRR) in treatment of patients with traumatic patellar dislocation. Methods 17 cases (6 male, 11 female) with traumatic patellar instability from March 2012 to December 2015, with an average age of 16.8 years old (range from 14 to 37 years old). All of the patients had a clear history of trauma and experienced patellar dislocation for the first time, the patients experienced patellar dislocation 1 to 4 times preoperatively. The arthroscopic examination was undertaken before the repairing to observe the injured site of the medial retinaculum and the patellar track, as well as the dynamic patellofemoral congruence. All patients underwent arthroscopic MRP and LRR minimally invasive procedure. Results All patients were followed up for 9 to 28 months averaging (19.7 ± 1.3) months. The fear test was negative after operation. There was no redislocation during follow-up and their ranges of motion returned to normal. Postoperative CT images showed 15 cases regained normal anatomical relation of patellofemoral joint. 2 cases had mild semi-dislocation. Lysholm's score averaging (51.8 ± 4.5) points preoperatively and (92.4 ± 2.8) points postoperatively. According to Insall scale, the results were excellent in 11 knees, good in 5 knees, and fair in 1 knee at 1 year after operation with an excellent and good rate of 94.1％. Conclusions Arthroscopic MRP and LRR showed satisfactory results with limited morbidity in the short-term follow-up. This method can make the patients smaller wound,quicker recovered and lower recurrence rate.
ABSTRACT
The possibility of rats mesenchymal stem cells (MSCs) modified with murine hyperpolarization-activated cyclic nucleotide-gated 2 (mHCN2) gene as biological pacemakers in vitro was studied.The cultured MSCs were transfected with pIRES2-EGFP plasmid carrying enhanced green fluorescent protein (EGFP) gene and mHCN2 gene.The identification using restriction enzyme and sequencing indicated that the mHCN2 gene was inserted to the pIRES2-EGFP.Green fluorescence could be seen in MSCs after transfection for 24-48 h.The expression of mHCN2 mRNA and protein in the transfected cells was detected by RT-PCR and Western blot,and the quantity of mHCN2 mRNA and protein expression in transfected MSCs was 5.31 times and 7.55 times higher than that of the non-transfected MSCs respectively (P＜0.05,P＜0.05).IHCN2 was recorded by whole-cell patch clamp method.The effect of Cs+,a specific blocker of pacemaker current,was measured after perfusion by patch clamp.The results of inward current indicated that there was no inward current recording in non-transfected MSCs and a large voltage-dependent inward and Cs+-sensitive current activated on hyperpolarizations presented in the transfected MSCs.IHCN2 was fully activated around -140 mV with an activation threshold of-60 mV.The midpoint (V50) was -95.1±0.9 mV (n=9).The study demonstrates that mHCN2 mRNA and protein can be expressed and the currents of HCN2 channels can be detected in genetically modified MSCs.The gene-modified MSCs present a novel method for pacemaker genes into the heart or other electrical syncytia.