ABSTRACT
Background: Acetabular fracture remains as a major challenge to orthopaedic surgeons despite of decades of improvement in its operative management. Unfavorable reduction is considered one of the key factors leading to joint degeneration and compromised clinical outcome in acetabular fracture patients. Besides the columns, walls, and superior dome, the postoperative position of hip joint center (HJC), which is reported to affect hip biomechanics, should be considered during the assessment of quality of reduction. Objectives: In this study, we aimed to quantify the postoperative shift of HJC radiographically, and to evaluate the relationship between the shift of HJC and the quality of fracture reduction following ORIF of acetabular fractures. Material and Methods: Patients with a displaced acetabular fracture that received open reduction and internal fixation in the authors institution during the past three years were identified from the trauma database. The horizontal and vertical shifts of HJC were measured in the standard anteroposterior view radiographs taken postoperatively. The radiographic quality of fracture reduction was graded according to Matta’s criteria. The relationships between the shift of HJC and the other variables were evaluated. Results: Totally 95 patients with 36 elementary and 59 associated-type acetabular fractures were included, wherein the majority showed a medial (92.0%) and proximal (94.0%) shift of HJC postoperatively. An average of 2.9 mm horizontal and 2.3 mm vertical shift of HJC were observed, which correlated significantly with the quality of fracture reduction (P < 0.001 for both). The horizontal shift of HJC correlated with the fracture type (P = 0.022). Conclusion: The restoration of HJC correlates with the quality of reduction in acetabular fractures following open reduction and internal fixation. Further studies are required to address the effects of HJC shift on the biomechanical changes and clinical outcomes of hip joint, especially in poorly reduced acetabular fractures.
ABSTRACT
Objective To study the clinical value of using a four-point method (FP) in measuring joint angles.Method Methods Twenty-five subjects without knee dysfunction were studied.Every knee joint was tested in extension,below 90° of flexion and above 90° of flexion with the traditional three-point method (TP) and the new four-point method.X-rays were taken as a gold standard measurement.The reliability and validity were analyzed using Bland-Altman plots,which can yield 95% limits of agreement (LOA).Results (1) The joint axis centers moved with changes in joint angle.(2) The 95% LOA of inter-tester reliability was (-5.0,2.7) with the FP and (-6.5,4.4) with the TP.The 95% LOAs of intra-tester reliability were (-3.6,4.0) for tester A and (-4.1,4.8) for tester B with the FP,while (-5.0,6.4) for tester A and (-6.1,5.8) for tester B with the TP.(3) The 95% LOAs in the three positions were (3.5,2.6) in extension,(-3.3,3.6) in mild flexion and (-1.9,5.7) in greater flexion with the FP,and ( 6.8,1.1),(-4.0,7.1) and (0,8.5) with the TP.Conclusions The FP gives better reliability and validity than the TP in joint angle measurement.
ABSTRACT
[Objective]To explore the effect of hip joint center on the stability of hip joint,the radiographic measurements were compared between preoperation and postoperation.[Method]A total of 155 hips from 120 patients with primary total hip replacement from resent years were studied,the hip joint center difference through radiographic measurements between preoperation and postoperation were compared.[Result]The coincident rate and the incoincident rate were 63.23%(group A,98 hips) and 36.77%(group B,57 hips) respectively.For loose,dislocation or low back pain,the rate of revision in group A and group B were 6.12% and 29.82% respectively.[Conclusion]The comeback of hip joint center was essential for stability of hip joint.
ABSTRACT
[Objective]To study the effect of femoral offset and hip joint center on joint function after total hip replacement,radiographic measurements were taken postoperation.[Method]A series of 92 hip joints(87 patients)were followed up.The average follow up priod was 25 monthes.The femoral offset and the position of the prothesis head center were measured in the orthophoric hip joint X-ray photograph and were compared with anatomic Fo and HJC.H arris evaluation system was used to evaluate joint function in four groups.The results were statistically analyzed,with Fisher' exact probability and P value less than 0.05 indicating significant difference.[Result]The coincidence rate of group A(both FO and HJC,27 hips)was 29.35%,group B(only Fo,23 hips)25.00%,group C(only HJC,31 hips)33.70%,group D(neither FO nor HJC,11 hips)11.96%.93.0% patients got the Harris score more than 80 for group A,73.19%(group B),74.19%(group C),27.27%(group D).The difference of Harris evaluation between A and B,A and C,A and D was significant statistically.[Conclusion]Based on the results of the study,the recovery of femoral offset and hip joint center should be considered to contribute to the healing effect after total hip replacement directly.