Analysis and multiple index evaluation of SPO distribution of bone traction needles for pelvic fracture reduction.

For robot-assisted pelvic fracture reduction, at least two bone needles need to be inserted into the ilium of the affected pelvis, and the robot clamping device is connected with the bone needles. The biomechanical properties of the pelvic musculoskeletal tissues are different with the different Spatial Position and Orientation (SPO) of the bone needles. In order to determine the optimal SPO of bone needle pairs, the constraints between the bone needles and the pelvis are analyzed, and the SPO vectors of 150 groups bone needles are obtained by the KNN-hierarchical clustering method; a batch modeling method of bone needles with different SPO is proposed. 150 finite element models of damaged pelvic musculoskeletal tissue with different SPO of bone needles are established and simulated. The stress and strain distribution homogenization of musculoskeletal tissue with bone needles as evaluation index, the simulation results of 150 models are evaluated. Results show that, the anterior superior iliac spine and the anterior inferior iliac spine are suitable regions to place bone needles in the pelvis, and the optimal distribution of the needle combination is found in this region. The overall stress and strain distribution of the damaged pelvic musculoskeletal tissue under the large reduction force is the best.

Development of on-line lateral stiffness measurement system for anterior cruciate ligament and its influence on anterior cruciate ligament reconstruction / 生物医学工程学杂志

The anterior cruciate ligament (ACL) reconstruction mostly relies on the experience of surgeons. To improve the effectiveness and adaptability of the tension after ACL reconstruction in knee joint rehabilitation, this paper establishes a lateral force measurement model with relaxation characteristics and designs an on-line stiffness measurement system of ACL. In this paper, we selected 20 sheep knee joints as experimental material for the knee joint stability test before the ACL reconstruction operation, which were divided into two groups for a comparative test of single-bundle ACL reconstruction through the anterolateral approach. The first group of surgeons carried out intraoperative detection with routine procedures. The second group used ACL on-line stiffness measurement system for intraoperative detection. After that, the above two groups were tested for postoperative stability. The study results show that the tension accuracy is (- 2.3 ± 0.04)%, and the displacement error is (1.5 ± 1.8)%. The forward stability, internal rotation stability, and external rotation stability of the two groups were better than those before operation (

Analysis on muscle force and injured femoral reduction force based on new muscle tendon model / 生物医学工程学杂志

Robot-assisted fracture reduction usually involves fixing the proximal end of the fracture and driving the distal end of the fracture to the proximal end in a planned reduction path. In order to improve the accuracy and safety of reduction surgery, it is necessary to know the changing rule of muscle force and reduction force during reduction. Fracture reduction force was analyzed based on the muscle force of femoral. In this paper, a femoral skeletal muscle model named as PA-MTM was presented based on the four elements of skeletal muscle model. With this, pinnate angle of the skeletal muscle was considered, which had an effect on muscle force properties. Here, the muscle force of skeletal muscles in different muscle models was compared and analyzed. The muscle force and the change of the reduction force under different reduction paths were compared and simulated. The results showed that the greater the pinnate angle was, the greater the influence of muscle strength was. The biceps femoris short head played a major role in the femoral fracture reduction; the force in the