Total knee arthroplasty (TKA) is an effective treatment for end-stage knee disease, with the postoperative alignment, component position, soft tissue balance, and prosthesis matching being key factors for the success of TKA. In order to achieve more accurate postoperative alignment and component position, better soft tissue balance and prosthesis matching for longer prosthesis longevity, better postoperative function and higher patient satisfaction, various intelligent accuracy technological aids such as computer assisted navigation (CAN), patient specific instrumentation (PSI), surgical robots, microsensors, customized implants (CI) and personalized 3D preoperative planning have emerged and are given high expectation. In this paper, the authors review the application and research progress of the above technological aids mainly from aspects of alignment, component position, clinical outcomes and cost analysis, so as to provide a reference for the application of related technological aids in TKA.

Objective To compare the efficacy of tibial tuberosity osteotomy (TTO) combined with medial patellofemoral ligament reconstruction (MPFLR) with simple TTO in treatment of recurrent patella dislocation associated with patella alta.Methods From July 2010 to December 2015,50 patients with recurrent patella dislocation and patella alta were included in this study.There were 15 males and 35 females with an average age of 20.6 years.These patients received surgical treatment and their clinical data were collected and retrospectively analyzed by case-control study.According to surgical methods,patients were divided into TTO group (32 cases) and MPFLR + TTO group (18 cases).The differences between preoperative status and postoperative status were evaluated by knee function scores including Tegner,international knee documentation committee (IKDC),Kujala scores,knee injury and osteoarthritis outcome score (KOOS).Patellar stability was checked at the last follow-up visit.Results The TTO group and MPFLR + TTO group were followed up for (50.9 ± 17.8) months and (22.3± 10.1)months,respectively.Two patients occurred recurrent dislocation in TTO group,who showed positive in both extrapolation test and extrapolation apprehension test at 0°flexions of knee.All patients in MPFLR + TTO group did not occur recurrent dislocation,who showed negative in both extrapolation test and extrapolation apprehension test at 0° flexions of knee.There was no significant difference between preoperative and postoperative results in TTO group in Tegner score (P ＞ 0.05),KOOS scores in pain and daily life activities subdomains (P ＞ 0.05),while differences in the rest of scores were statistically significant (P ＜ 0.05).Compared with TFO group,the differences of all scores were statistically significant (P ＜ 0.05) and KOOS scores in the pain and daily life activities subdomains were significantly improved postoperatively in MPFLR + TTO group P ＜0.05).Conclusions For patients with recurrent patellar dislocation associated with patella alta,both surgical methods are found to be effective.Postoperative improvements in pain and daily life activities are less obvious in TTO.While postoperative improvements in pain and daily life activities in MPFLR + TTO are superior to those of TTO.

Objective:To explore the effects of mechanical factors on the morphology of the growth plate and proximal femur development, in order to provide a mechanical basis for the mechanism of Cam lesions in femoral acetabular impingement (FAI).Methods:Using CT scan data of hip joint from adolescents, we constructed three-dimensional finite element models of normal and extended proximal femoral epiphyseal growth plates. Dynamic mechanics and position data from daily activities (walk, stand on one and two feet, go upstairs and downstairs, sit and stand up, squat and stand up) and basketball layup drills were collected from five healthy volunteers using the Vicon system. The mean values of femoral head mechanical loads and positions at peak values, movement onset, and termination were selected for finite element analysis to observe the distribution of equivalent stress, normal stress, and shear stress on the two growth plate models under different activity modes.Results:Successful construction of three-dimensional finite element models for normal and extended proximal femoral epiphyseal growth plates was achieved. Mechanical load values and spatial positions of the femoral head during daily activities and layup movements were obtained. In daily activities, peak equivalent stress values for normal and extended growth plates ranged from 1.6 to 11.0 MPa; compressive stress ranged from 1.7 to 12.0 MPa; tensile stress ranged from 0.5 to 10.0 MPa; and shear force ranged from 0.4 to 7.1 MPa. The compressive stress during walking, standing on one or both feet, going up and down stairs, sitting and standing, and squatting was concentrated in the central and lateral areas; tensile stress was concentrated in the central and medial areas; shear force was concentrated in the medial area and the anterior and posterior edges of the growth plate. During a layup, the compressive stress in the center, outer upper side, and medial edge of the growth plate of the normal model was notably concentrated, with peaks fluctuating between 5.5-19.0 MPa, 5.7-11.0 MPa, and 5.4-7.3 MPa respectively; tensile stress and shear force were concentrated at the inner and outer edges as well as in the central area, with peaks fluctuating between 3.0-24.0 MPa and 3.0-26.0 MPa respectively, these values were significantly different from those observed during daily activities. For the elongated growth plate, compressive stress was concentrated at the central and lateral edges with peaks fluctuating between 17.0-41.0 MPa and 17.0-38.0 MPa respectively; simulated shear stress and tensile stress showed significant concentration at peaks fluctuating between 4.9-34.0 MPa, also significantly different from those observed during daily activities.Conclusion:The difference in mechanical distribution between daily activities, basketball layup training, as well as between normal and extended growth plates may be the mechanical initiating factor in the development of extended growth plates and the formation of Cam lesions, it may be the mechanical initiating factor for the development of extended growth plates and the collision of Cam lesions in FAI.