Objective To evaluate the efficacy of the thoracic approach to thoracic paravertebral blockade ( PVB) performed via video-assisted thoracoscope on postoperative analgesia in patients undergoing lobectomy. Methods A total of 84 patients of both sexes, aged 44-64 yr, with body mass index of 19. 7-24. 9 kg∕m2 , of American Society of Anesthesiologists physical statusⅡorⅢ, scheduled for elective vide-o-assisted thoracoscopic unilateral lobectomy, were divided into 2 groups ( n=42 each) using a random number table method: thoracic PVB group (TP group) and control group (C group). In TP group, the thoracic approach to thoracic PVB was performed on the affected side via video-assisted thoracoscope before closing the chest, and 0. 375％ ropivacaine hydrochloride 20 ml was injected. Then patient-controlled intra-venous analgesia ( PCIA) was performed in both groups. PCIA solution contained dezocine 0. 6 mg∕kg, flurbiprofen axetil 200 mg, palonosetron 0. 5 mg and dexamethasone 10 mg in 120 ml of normal saline. The PCA pump was set up with a 0. 5 ml bolus dose, a 15 min lockout interval and background infusion at a rate of 2 ml∕h after a loading dose of 5 ml. Duration of operation was recorded. The peak expiratory flow rate ( PEFR) was recorded before surgery and at 6, 24 and 48 h after surgery. The amount of dezocine and pressing times of PCA were recorded at 24 and 48 h after surgery. The occurrence of drowsiness, dizziness, nausea and vomiting was recorded after surgery. Tramadol 2 mg∕kg was intravenously injected as rescue an-algesic when visual analog scale score≥4 points. Results Compared with group C, the amount of dezo-cine and pressing times of PCA were significantly reduced at 24 and 48 h after surgery, the requirement for rescue analgesia and incidence of nausea and vomiting were decreased, and the PEFR was increased at 6 h after operation in group TP ( P<0. 05) . Conclusion The thoracic approach to PVB performed via video-assisted thoracoscope can enhance the efficacy of postoperative analgesia in patients undergoing lobectomy.

Objective To compare and analyze the lower limb muscle activity and knee joint force during the stance periods of gait cycle in patients with osteoarthritis before and after total knee arthroplasty (TKA). Methods Based on the OpenSim platform, lower extremity musculoskeletal models of one healthy subject and three patients with osteoarthritis before and after TKA were established. A three-dimensional （3D） motion capture system and a force platform were used to collect the lower limb kinematic data and the ground reaction force during walking, which were used as input parameters to simulate the lower limb muscle activation and knee joint forces. Results The results from the musculoskeletal model were consistent with the results by inverse dynamics based on the 3D motion capture system. The patient's rectus femoris was activated in the loading response and mid stance phases, which was different from that of healthy subject. The activation timing and amplitude of the quadriceps muscle in 3 patients were significantly different before and after TKA. The peak joint forces of 3 patients before TKA were 2.95, 3.15 and 3.43 times of body weight (BW) with the constant load of more than 2 times of BW during stand phase. The peak joint force after TKA were 2.09, 2.48 and 3.96 times of BW respectively. The joint force was not improved and the knee function did not reach the normal level six months after TKA. Conclusions The results of the established musculoskeletal model have certain reliability, and this model can provide a biomechanical auxiliary method for TKA surgery in the future.