ABSTRACT
Proximal tibial aspect ratio (PTAR) is closely related to age, disease status and cutting parameters with considerable inter-individual variation independent of gender and race, nevertheless the aspect ratio of tibial components from different manufacturers remains relatively constant from smallest to largest size. As a result, component mismatching is an unavoidable dilemma during tibia preparation in total knee arthroplasty (TKA). Various prosthesis systems all can achieve more than 80% coverage on proximal tibia, whereas their optimal fit rates are generally not more than 50%. It is difficult for symmetrical components to avoid anteroposterior mismatch, internal malrotation tends to occur when maximum coverage is pursued on the resected surface with a medial dominant plateau or lower PTAR. Although it is easier to achieve a balance of rotation and coverage with anatomical components, significant anteromedial overhang tends to appear on the resected surface with a symmetrical or lateral dominant plateau. Further researches should focus on the law of inter-individual variability of proximal tibial morphology, the quantitative definition of "ideal matching" safety zone of key morphological parameters on different areas of proximal tibia and the methodology of realizing"ideal matching"in the majority patients with the least amount of component sizes. In addition, with the rapid development of additive manufacturing and digital orthopedic technology, individual customized implant is expected to become a breakthrough point in the field of TKA component fitting.
ABSTRACT
ObjectiveTo analyze characteristic changes of shoulder muscles by investigating surface electromyographic regularity changes before and after the treatment of Frozen shoulders. Methods7 cases of frozen shoulders were selected, surface electromyography (sEMG) before and after treatment were recorded by AMT-8 EMG recorder. The collected data was processed using MATLAB software integrated EMG (IEMG) value were obtained. Then the IEMG data were statistically analyzed using Stata11.0 software and compared. Results ①The differences of abduction deltoid and infraspinatus muscle IEMG values before and after treatment were statistically significant(P ＜0.05), while IEMG values changes of biceps, triceps, pectoralis major, latissimus dorsi and trapezius before and after treatment were not statistically significant (P＞0.05); changes of adduction IEMG values of all muscles were not statistically significant (P＞0.05). ②Changes of flexion IEMG values of biceps before and after treatment were statistically significant (P＜0.05), while IEMG values changes of pectoralis major, infraspinatus muscle, latissimus dorsi, trapezius, deltoid, triceps before and after treatment were not statistically significant (P＞0.05). Changes of extension IEMG values of triceps before and after treatment were statistically significant (P＜0.05), while those of pectoralis major, infraspinatus muscle, latissimus dorsi, trapezius, deltoid and biceps were not statistically significant (P＞0.05). ③IEMG values of all the muscles during external rotation, internal rotation before and after treatment IEMG were not significantly different. Conclusion①After treatment, the outreach functions of infraspinatus and deltoid muscles were improved, while adduction functions of all muscles were not improved. ②Flexion function of biceps was improved significantly after treatment as well as extension function of triceps.③Extemal rotation, internal rotation functions of all muscles were not improved significantly.