Reliability of tibial anterior crest as the anatomical reference of rotating alignment for tibial component in total knee arthroplasty / 中国骨伤

OBJECTIVE@#This study aimed to research whether anterior tibial crest is a reliable anatomical reference for rotational alignment of tibial component in TKA.@*METHODS@#The study included 122 patients who underwent computed tomography angiography (CTA) examination for unilateral lower extremity trauma with normal contralateral lower extremities, including 89 males and 33 females, with an average age of(51.4±16.4) years old(ranged 18 to 81 years old). Picture archiving and communication system (PACS) was used to mark 11 lines including the surgical epicondylar axis (SEA) connecting the most prominent points of the lateral epicondyle and the deepest point of the sulcus on the medial epicondyle of the femur, axis of medial border of patellar tendon (MEPT)connecting the middle of the posterior cruciate ligament (PCL) and medial border of the patellar tendon at the level of a standard tibial cut from 8 mm distal of the lateral tibial joint surface, transverse axis of tibia (TAT) at the level of a standard tibial cut from 8 mm distal of the lateral tibial joint surface, Akagi line connecting the projected middle of the PCL and medial border of the patellar tendon at the tibial attachment, the axis of the medial 1/3 of patellar tendon(M1/3) connecting the projected middle of PCL and the medial 1/3 of the patellar tendon at the patellar tendon attachment level, Insall line connecting the projected middle of the PCL and the medial 1/3 of tibial tubercle, the axis of medial border of tibial tubercle (MBTT) connecting the projected middle of the PCL and medial border of tibial tubercle, as well as the axis of the proximal anterior tibial crest (PATC), axis 1 of the middle anterior tibial crest (MATC1), axis 2 of the middle anterior tibial crest (MATC2) and the axis of the distal anterior tibial crest (DATC) which were marked by connecting the 4 equidistant points on the sharp anterior tibial crest and the projected middle of the PCL. The angles between TAT and SEA as well as the angles between other axes and the perpendicular to SEA were measured. Pairwise differences among the 10 tibial axes were examined using One-Way ANOVA and paired @*RESULTS@#The angles between the axes of MEPT, Akagi line, M1/3, Insall line, MBTT, PATC, MATC1, MATC2, DATC and the perpendicular to SEA were (-1.6 ±4.5)° , (1.4 ±5.0)° , (10.2±5.1)°, (11.9±5.4)°, (3.6±4.8)°, (12.0±6.9)°, (7.2±8.6)°, (7.1±10.4)°, (6.6±13.5)°, respectively. The angle between TAT and SEA was (4.1±5.3)°. MEPT was external rotation compared to SEA. M1/3, Insall line and PATC were significantly greater than Akagi line, MBTT, TAT (@*CONCLUSION@#The middle tibial anterior crest can be used as a reference for rotational alignment of tibial component in TKA, and its reliability is better than Insall line, but worse than Akagi line, TAT and MBTT.

Long-Term Evolution of the Electrical Stimulation Levels for Cochlear Implant Patients

OBJECTIVES: The stimulation levels programmed in cochlear implant systems are affected by an evolution since the first switch-on of the processor. This study was designed to evaluate the changes in stimulation levels over time and the relationship between post-implantation physiological changes and with the hearing experience provided by the continuous use of the cochlear implant. METHODS: Sixty-two patients, ranging in age from 4 to 68 years at the moment of implantation participated in this study. All subjects were implanted with the 12 channels COMBI 40+ cochlear implant at San Cecilio University Hospital, Granada, Spain. Hearing loss etiology and progression characteristics varied across subjects. RESULTS: The analyzed programming maps show that the stimulation levels suffer a fast evolution during the first weeks after the first switch-on of the processor. Then, the evolution becomes slower and the programming parameters tend to be stable at about 6 months after the first switch-on. The evolution of the stimulation levels implies an increment of the electrical dynamic range, which is increased from 15.4 to 20.7 dB and improves the intensity resolution. A significant increment of the sensitivity to acoustic stimuli is also observed. For some patients, we have also observed transitory changes in the electrode impedances associated to secretory otitis media, which cause important changes in the programming maps. CONCLUSION: We have studied the long-term evolution of the stimulation levels in cochlear implant patients. Our results show the importance of systematic measurements of the electrode impedances before the revision of the programming map. This report also highlights that the evolution of the programming maps is an important factor to be considered in order to determine an adequate calendar fitting of the cochlear implant processor.