ABSTRACT
BACKGROUND: The ROM technique has been widely used to determine the rotational alignment of tibial prosthesis in total knee arthroplasty, but the accuracy of this technique remains controversial. However, there is no report on the influencing factors of ROM technique. OBJECTIVE: To explore the influencing factors of ROM technique in determining the rotational alignment of tibial prosthesis in total knee arthroplasty. METHODS: Totally 61 patients underwent unilateral knee arthroplasty, including 18 males and 43 females, aged between 55 and 78 years. All patients were diagnosed as knee osteoarthritis before operation. All operations were performed with the posterior cruciate-stabilizing total knee prostheses. All patients signed the informed consent. This study was approved by the Hospital Ethics Committee. The rotational orientation of the tibial prosthesis was determined by the ROM technique with closed and unclosed medial retinaculum. A line from the center of the posterior cruciate ligament to the medial border of the patellar tendon was used as the anteroposterior axis of tibia (Akagi line). The angles between the anteroposterior axis of tibia and lines determined by the ROM technique were measured to identify the classification of patellar track so as to decide whether the classification of patellar track, closing and unclosing medial retinaculum are the influencing factors of ROM technology. RESULTS AND CONCLUSION: (1) The angles between the Akagi line and lines determined by the ROM technique respectively were (0.5±2.5)°, (-0.9±2.6)°, and (-3.9±3.4)° for the unclosed medial retinaculum and (0.6±2.3)°, (-0.3±2.2)°, and (-1.5±2.9)° for the closed medial retinaculum. (2) For type III patellar track, the angle between line determined by the ROM and Akagi line was significantly internal rotation compared with type I and type II patellar track (P 0.05). For type III patellar track, closing the medial retinaculum could significantly reduce the difference between Akagi line and the line determined by ROM technology (P < 0.05). (4) These results indicate that for type I and type II patellar track, ROM technique can accurately locate the rotational alignment of tibial prosthesis in total knee arthroplasty, and closing or unclosing the medial retinaculum will not affect the accuracy of the results. As to type III patellar track, whether or not the medial retinaculum is closed may lead to failure in determining the rotation alignment of the tibial prosthesis.
ABSTRACT
Objective To investigate the eyelid and orbital development of congenital microphthalmia. Design Prospective case se- ties. Participants 23 eyes of 23 patients with congenital microphthalmia aged from 6 months to 78 months. Methods The parameters of palpebral fissure length (PFL), palpebral fissure height(PFH) were measured in all patients. Also, combining the computer tomography (CT) imaging with the computer-aided design system, the anteroposterior axis of eyeball and orbital volumn were calculated automatically. To e- valuate the influence factor of eyelid and orbital growth, correlations between age, anteroposterior axis of eyeball and PFL, PFH, orbital volumn were analyzed. Main Outcome Measures PFL, PFH, anteroposterior axis of eyeball and orbital volumn. Results The PFL, PFH, anteroposterior axis of eyeball and orbital volumn in micro-side were (16.44?3.24) mm, (2.47?1.48) mm, (11.99?3.33) mm, (14.19?2.37) ml respectively. These parameters above were all significantly smaller than the unaffected side (all P=0.000). Moreover, orbital volume showed a strong linear correlation with the anteroposterior axis of eyeball and age(r=0.62, 0.63;p=0.037, 0.035). Both PFL and PFH were corelated with the anteroposterior axis of eyeball (r=0.54, 0.53; P=0.030,0.034), while showing no significant difference with age. According to the an- teroposterior axis of eyeball, two groups, including group less than or equal to 12 mm (10 cases) and group more than 12 mm (13cases), whose PFL,PFH and orbital volumn were (13.50?1.97) mm, (1.08?0.66) mm; (12.73?0.95) ml, (18.20?2.49) mm; (3.30?1.16) mm, (15.05?2.57) ml, respectively. They had statistically significant difference in PFL, PFH and orbital volumn (P=0.001, 0.003,0.024). Conclusion The development of eyelid and orbit with congenital microphthalmia is obviously retarded. The smaller the eyeball is, the much worse in- fluence in eyelid and orbital growth is. The intervention therapy in early stage as far as possible is fundamental approach in simulating the eyelid and orbital development, or preventing and reducing the incidence of orbital deformity.
ABSTRACT
PURPOSE: The degree of external rotation produced by the gap technique in total knee arthroplasties (TKA) was measured and compared with other methods. MATERIALS AND METHODS: Thirty-nine TKA patients (52 cases) were enrolled in this study. The transepicondylar axis (TEA) and the perpendicular line to the anteroposterior axis (APA) were drawn on the images of the computerized tomographs (CT). After resecting the posterior condyles using the gap technique, the maximal depths of the resected fragments were measured, and the resected lines (RL) were drawn on the same CT images. The differences in the angles between the RLs and the TEAs, the perpendicular lines to the APAs, and the lines that were externally rotated 3o from the posterior condylar axes, were evaluated. RESULTS: The posterior condylar axes formed 5.1+/-2.5 degrees angles with the RLs, 5.3+/-1.6 degrees angles with the TEAs, and 4.5+/-2.1 degrees angles with the lines that were perpendicular to the APAs. The RLs showed similar TEAs, and the APAs (0.2+/-2.6 degrees and 0.6+/-3.0 degrees, respectively). However, the lines of 3 degrees external rotation (2.1+/-2.5 degrees) were significantly different. CONCLUSION: A more ideal flexion gap could be obtained with the TEAs compared with other methods. However, resections of the posterior condyles using the gap technique might be more effective than with the TEAs due to the individual variations and errors in obtaining symmetric flexion gaps with this value.
Subject(s)
Humans , Arthroplasty , Axis, Cervical Vertebra , Knee , TeaABSTRACT
PURPOSE: We compared the tansepicondylar axis and the anteroposterior axis used as the references for the rotational axis of the femur when performing total knee arthroplasty and determined effect of varus deformity on two axes. MATERIALS AND METHODS: This study was conducted in 49 patients (69 cases of knees) with osteoarthritis who underwent preoperative computerized tomography (CT). The control group included 53 patients having no arthritis (53 cases) who underwent preoperative MRI for meniscal injury. On CT and MRI images, angle between tansepicondylar axis and the posterior condylar axis (posterior epicondylar angle) and angle between anteroposterior axis and posterior condylar axis (anteroposterior angle) were measured. Then, the data of two groups were compared. RESULTS: The average posterior epicondylar angle in the knee osteoarthritis group was 5.4 degrees +/-1.8, whereas that in the control group was 5.9 degrees +/- 1.6. The average anteroposterior angle in the osteoarthritis group was 3.8 degrees +/-1.6, whereas it was 3.9 degrees +/- 1.5 in the control group showing a significant difference from westerners. There was significant difference between posterior epicondylar angle and anteroposterior angle. But, no significant difference was seen in posterior epicondylar angle and anteroposterior angle between two groups. CONCLUSION: According to this study, the transepicondylar axis showed an average external rotation of 5.4 degrees , which was larger than 3 degrees recommended in usual total knee arthroplasty. The anteroposterior axis showed an average external rotation of 3.8 degrees . Varus deformity due to osteoarthritis had no significant effect on two axes. When femoral component is inserted, using only one axis to obtain correct rotational alignment caused problems because of considerable individual differences of two axes and we should consider two axes for correct rotational alignment.
ABSTRACT
PURPOSE: To know the discrepancy of rotational alignment using human femur. MATERIALS AND METHODS: We used 22 adult human femurs which were not able to distinguish age and sex and absent articular cartilage. In a horizontal plane, we made a cross-section perpendicularly at supra-condyle of femur to a mechanical axis and took a simple roentgenogram in coronal plane focusing on the center of transepicondylar axis. In terms of roentgenogram and gross specimen, the angle between per-pendicular to the anteroposterior axis and the posterior condylar axis, the angle between the transepi-condylar axis and the posterior condylar axis were measured by 5 observers. According to t-test in statisti-cal method, we figured out the difference between two angles and made a significance at p<0.05. RESULTS: About posterior condylar axis, the line perpendicular to anteroposterior axis was observed the average 4.8(+/-1.5)degree, 6.0(+/-1.9)degree external rotation in roentgenogram and gross specimen respectively. The transepicondylar axis was observed the average 3.5(+/-1.2)degree, 3.9(+/-1.4)degree external rotation in roentgenogram and gross specimen respectively. There was statistically significant difference between two angles. Moreover, angles measured by 5 observers were found that to have a line perpendicular to the anteroposterior axis has much more external rotation respectively and there was a statistically significant difference also. CONCLUSIONS: On determination of a rotational alignment using human femur, there is statistically sig-nificant difference between the anteroposterior axis and the transepicondylar axis in gross specimen as well as roentgenogram.