Objective To explore the effect of the antero-posterior translation of the femur on the maximum knee flexion and the relative movement of the femur for the three different kinds of prosthesis after total knee arthroplasty(TKA), such as posterior-stabilizing, fixed-bearing and mobile-bearing with the PCL retention. Methods 25 patients were selected for each kind of the prosthesis, and the inclusion criterion was based as the knee OA, good-excellent outcome after TKA, the flexion of the knee beyond 90?, and more than one year follow-up. The average age of these patients was 68 years with a range of 63 to 77 years, which involved 32 males and 43 females. The average preoperative knee flexion in the three groups were 77.8??15.1?, 80.1??12.9? and 76.4??12.7? respectively. The roentgenograms were taken both at the knee extension and maximum flexion, then the femur translation and the knee flexion were measured. Results The difference of the knee flexion among three groups preoperatively was of no significance. The maximum postoperative knee flexion in the posterior stabilizing, fixed-bearing and mobile-bearing was 118.0??7.1?,108.7??7.9? and 100.2??8.3? respectively. The analysis of variance showed the difference was of significance (F=32.86, P=0.0001). The relative movement about the femoral prosthesis in the three groups were (6.3?2.5) mm, (1.2?4.6) mm and ( 4.7?3.7) mm respectively (the posterior movement was positive, and the anterior was negative). The difference was of significance(F=57.71, P=0.0001). The femoral antero-posterior translation was proved to have correlation with the maximum knee flexion. Conclusion The femoral translation among three groups are different in manner, accordingly, the maximum knee flexion was different too.

Objective To provide an essential features of the knee for the prothesis design more suitable in Chinese. Methods 240 knees of 120 healthy Chinese adults were selected on trial, with an average age of 30.6 years (range, 21 to 40 years) and an average height of 1.68 m ranging from 1.60 m to 1.75 m. Each individual was asked to do deep flexion activities. Fluoroscopy were used to determine accurately the weightbearing kinematics in vivo of 240 knees at different position. The anterior articular surface of the femoral condyle was designated as the "extension facet"(EF), while the posterior surface as the "flexion facet"(FF). Their centers are labelled as EFC and FFC respectively. The distances between the ipsilateral posterior tibial cortex and the center of the posterior femoral condylar circles at different position were measured by drawing a line through the most protruding points in the medial and lateral tibial subchondral bony landmark. A second line was drawn perpendicular to the first and tangent to the posterior tibial cortex. The distance d1 and d2 were measured perpendicularly from FFC and EFC to the second line respectively. The change of d1 and d2 in different positions denoted the relative movement between the tibia and femur. The data were used by ANOVA analysis containing two factors with SAS software. Results The difference of sex and side had no influence on the relative movements between the tibia and femur. In normal adults, the range of relative motion at the medial and lateral condyle during deep flexion was (1.4?0.3) mm and (15.9?4.7) mm respectively. Conclusion The lateral condyle undergoes posterior translation including sliding and rolling significantly during the deep flexion that leads to the relative axial rotation of the tibia to the femur.

Objective In order to investigate the effectiveness of unique cyclic biomechanical stretch on proliferation, alkaline phosphatase (ALP) activity and osteopontin (OPN) mRNA of colonal murine osteoblast-like cell line MC3T3-E1 in three-demensional culture. Methods Gelatin sponges with a size of 2.00 cm?2.00 cm?0.25 cm were used as the three-demensional culture vector of MC3T3-E1, 100 ?l cell suspension was applied to the surface of sponge, the cell number was 1.25?105. The gelatin sponges could be stretched to 5% with 60 cycles/min and 15 min/h on computerized bio-stretch controller. At 2, 4, 6, 8 and 10 d after stretch stimulation, three samples were collected at each time point from the stretch and con-trol group respectively. Cell counting, activity assay of ALP both of cells and medium as well as OPN mRNA measurement were carried out. Results The cell number of the stretch group was more than that of control group from 2 d (P

Objective To investigate the influence and clinical significance of knee lateral thrust gait to femorotibial angle and lateral joint space in the patients with knee varus deformity. Methods 44 patients (male 10, female 34; range 31-60 years old, mean 41 years old) with knee varus deformity and lateral thrust involved in this study. The femorotibial angle and lateral joint space were measured on the standing anteroposterior film (single-foot loading and double-feet loading) of knee in order to compare the changes of them. The double-feet loading film simulated the corresponding relationship between thighbone and tibiae at double-support time, as early knee lateral thrust. The single-foot loading film simulated the corresponding relationship between thighbone and tibiae at single-support time, as late knee lateral thrust. The changes of femorotibial angle and lateral joint space in the two positions showed the changes of corresponding relation between thighbone and tibiae during knee lateral thrust. Results The mean femorotibial angle was 188.50??4.48? and 185.50??4.46? at the time of single-foot loading and double-feet loading respectively. It indicated that the femorotibial angle was increasing at the time of single-foot loading. The mean width of lateral joint space was (9.92?0.86) mm and (7.70?0.78) mm at the time of single-foot loading and double-feet loading respectively. It demonstrated that lateral joint space was widening more at the time of single-foot loading. The result suggested the lateral thrust of knee led to these changes. The increasing of femorotibial angle meant an increase of knee adduction moment during gait. The increasing of lateral joint space led to lateral structures chronic instability. The increased knee adduction moment and lateral structures chronic instability were the important mechanisms for degeneration of knee medial department. Conclusion The knee lateral thrust gait results in the augments of femorotibial angle and lateral joint space. These lead to the increase of the load on knee medial compartment, lateral structures chronic instability and varus deformity increasing. Lateral thrust might cause aggravation of knee varus and gonarthrosis at knee medial compartment.

Objective To evaluate whether the presence of subchondral bone marrow edema (BME)in magnetic resonance imaging(MRI) are associated with the different levels of knee pain among the patients suffering osteoarthritis(OA). Methods Based on rating scale of pain, 264 patients with knee OA were divided into three groups: 47 in the no pain group, 184 in the mild pain group, 33 in the moderate or severe pain group. Contingency table analyses and rank sum tests were used to compare the difference of OA stage and BME score among these groups. OA was classified by the X-ray as the Kellgren-Lawrence(K-L) scoring scale system: 52 mild(K-L Ⅱ degree), 142 middle(K-L Ⅲ degree), 70 severe(K-L Ⅳ degree); while BME was identified from MRI: 69 with grade 0(no BME), 127 with grade 1(small BME), 68 with grade 2(large BME). Results There were no statistical significance of OA stage among three pain groups(?2=5.251, P=0.263), though severe OA were more likely to occur in moderate or severe pain group as compared with the no pain and mild pain groups(42.4% vs 23.4% and 24.5%). Also in the three groups, the prevalence of each score BME was of great significant difference(?2=28.157, P

[Objective]To analyze the reasons of complications in high tibial valgus osteotomy in the varus osteoarthritic knee and its management.[Method]We studied the results of valgus-producing high tibial osteotomies in patients who had medial unicompartmental osteoarthritis and varus malalignment.We performed the operation for 126 patients from January 2000 to October 2004.Twenty-one patients had complications,including four men and seventeen women,with average age of 61 years(ranged:48～64 years).The femorotibial angle was measured on the standing anteroposterior film of knee preoperatively in order to get high accuracy in preoperative planning.A lateral closing-wedge osteotomy was performed,the osteotomy site was stabilized by Giebel blade plate or stepped staple.[Result]The mean duration of follow-up was 7.5 months(ranged,6 to 12 months).There were twenty-three complications(21 patients,16.7%):tibial fracture in four cases,deep-vein thrombosis in five cases,peroneal nerve palsy in three cases,recurrence of varus deformity in six cases,internal fixation failure in four cases(recurrence of varus deformity developed in two patients),a superficial wound infection developed in one patient.[Conclusion]To reduce the incidence of complications in high tibial valgus osteotomy,we should make familiarication with anantomy and take more accuracy in preoperative planning,improve surgical skill as well as appropriate perioperative management.

Objective To evaluation high tibial osteotomy combined with anteromedial transfer of the distal fragment for the treatment of medial and patellofemoral compartmental osteoarthritis of the varus knee. Methods High tibial osteotomy was performed in 30 knees of 24 patients with medial and patellofemoral compartmental osteoarthritis of the varus knee, which was combined with anteromedial transfer of the distal fragment. The patients included 5 males (7 knees), 19 females (23 knees), with the mean age 53 years (range, 49-55 years). All patients were followed-up with footprints to assess the foot progression angle preoperatively and at 6 months to 2 years after the osteotomy. Tibial torsion of these subjects was measured by computerized tomography preoperatively and after the osteotomy. The statistical evaluation was carried out by the paired t test. Results The foot progression angle was 8.95??2.99? preoperatively, and -2.23??4.11? postoperatively during walking. The tibial torsion was 33.77??8.12? preoperatively and 21.27??8.48? after the osteotomy. The statistical evaluation showed foot progression angle and tibial torsion preoperative were significant difference from those postoperative (P 0.05). This result revealed that the decrease of foot progression angle was equal with the decrease of tibial torsion postoperatively. Conclusion High tibial osteotomy combined with anteromedial transfer of the distal fragment may be the effective method for medial and patellofemoral compartmental osteoarthritis of the knee, but it would cause calf and foot internal rotation. The change of foot progression angle and tibial torsion can influence the effect of high tibial osteotomy. The magnitude of anteromedial transfer of the tibial tubercle must be individualized and be devised preoperatively. It is important to evaluate patellofemoral malalignment and to measure the magnitude of tibial internal rotation in operation.

[Objective]To assess the functional outcome,influence factors and its management of lateral wedge high tibial osteotomy(HTO)in patients with symptomatic lateral thrust and varus malalignment.[Method]The results of 19 lateral closing wedge HTOs in patients with a symptomatic hyperextension-varus thrust were evaluated from 2000 to 2004.The average age of the patients at the time of surgery was 49 years(ranged,47~54 years).Radiographs were analyzed to compare changes in femorotibial angle,tibial slope,and the height of the fibular head pre-and postoperatively.Functional results were evaluated according to the scoring system of HSS.The varus stress test was used to evaluated the posterolateral knee injury.We used a 5-point visual analogue scale to assess change in knee stability.[Result]Patients were followed for an average of 21 months.Femorotibial axis alignment was 184.5?～197?preoperatively and 167?～176?postoperatively;Posterior tibial slope was 2?～17?preoperatively and-4?～13?postoperatively;The height of fibular head was 7.7～18.5 mm preoperatively and-3.5～10.7 mm postoperatively(P=0.00).All patients had an increase in their HSS score postoperatively.Sixteen patients had Grade 1 posterolateral injuries and 3 patients had Grade 2 injures preoperatively,9 patients had Grades 1 injures and 10 patients had Grade 2 injures(P

Objective The purpose of this study was to observe the feature of tunnel enlargement after anterior cruciate ligament reconstructions and to investigate the influencing factors and the relationship between bone tunnel enlargement and clinical outcome. Methods There were 103 patients who accepted anterior cruciate ligament reconstructions with autogenous hamstring tendons for follow-up. Magnetic resonance imaging(MRI) offered the possibility of visualizing the bone tunnels from 12 to 18 months after surgery. The width was measured for tibial and femoral tunnel and compared to initial width. The tunnel size was graded to 4 grade depending on the increased width: grade 0(

[Objective]To clarify the precise displacement of the popliteal artery(PA) during knee flexion using magnetic resonance imaging(MRI).[Method]MRI was used in 16 knees at 0? and 90? of flexion to measure the distance between the popliteal artery and the posterior tibial cortex(bone to artery distance,BAD)at two levels corresponding to the levels of osteotomy in total knee arthroplasty(TKR) and in high tibial osteotomy(HTO).The results were analysed using paired-samples t test.[Result]At the level of TKR(0.5 to 1 cm below the tibial articular surface),the mean posterior movement of BAD from extension to 90? of flexion was 1.8 mm(-2～+5 mm) with a statistical significance(P=0.005).At the level of HTO(1.5 to 2 cm below the tibial articular surface),the mean change in BAD 1.4mm(-2～+4mm)was also statistically significant(P=(0.005)).At the two levels,the artery moved toward the tibia in 2 cases,respectively.[Conclusion]Knee flexion may be considered to be a safer position,still there is possible potential popliteal artery injury.