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Objective To investigate the stress distribution in a cemented femoral component in elderly patients with a partial marrow type Ⅰ intertrochanteric fractures and to compare differences in the stress distribution after a long-and short-stem prosthetic replacement.Methods Spiral CT images of right femur of the volunteer were obtained and processed with Mimics software and modeling software to reconstruct a three-dimensional model of the femur.Based on this,a three-dimensional physical model for partial marrow type Ⅰ intertrochanteric fractures,long-and short-stem femoral prostheses,and cement mantle was established.Subsequently,a three-dimensional finite element model of long-and short-stem prosthetic replacement for intertrochanteric fractures was established using the finite element analysis software,and biomechanical analysis was implemented for the model.Results No significant changes in stress distribution of the femur occurred after long-or short-stem prosthetic replacement.Stress on the femur still presented a gradual increase from the proximal end to the distal end,peaked at the lower 1/3 of the medial and lateral junction and then decreased at the end.A stress concentration zone formed in the medial and lateral end of cement-stem interface in short-stem prosthetic replacement.Besides,the maximum value of stress in the lateral interface reached 15.3 MPa,but without surpassing the fatigue strength of the bone cement.Whereas,a stress concentration zone formed in the distal medial and lateral part of cement-stem interface and the medial middle part of the interface in long-stem prosthetic replacement and the maximum value was also lower than the fatigue strength of bone cement.No significant stress concentration zones were found in the femoral calcar reconstructed using bone cement.Conclusions Cemented long-or short-stem prosthetic replacement achieves no significant alteration in stress distribution of the femur.Loosening probability of the cemented long-or short-stem prosthesis is almost the same,but the latter has advantages of shorter surgery time,minor trauma,and fewer complications and may be more suitable for treatment of the elderly patients with a partial marrow type Ⅰ intertrochanteric fractures.
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Objective To discuss and analyze effect of biotype common handle (short handle) prosthesis in treating aged patients with femoral intertrochanteric fracture.Methods A retrospective analysis was carried out on 321 patients,among which 280 (102 males and 178 females,at age of 72-98years,average 82.5 years) obtained follow-up.According to a new fracture classification method (Piansui Classification),the typeⅠ a fracture was found in 65 cases and type Ⅰ b in 215.Most patients were combined with medical diseases,and after related medical collaborative treatment,standard biotype common handle prosthesis (artificial bipolar femoral head) replacement was applied to all patients.Early rehabilitation exercise was performed postoperatively.Results All the 321 patients lived through perioperative period successively,with no death in hospitalization.Meanwhile,postoperative complications were all cured in hospitalization.The patients could take out-of-bed activity at 1-3 weeks after operation.All 280 patients could take care of themselves at 12-46 months (average 28 months) of follow-up.According to Harris score,the results were excellent in 129 cases,good in 121,fair in 22 and poor in eight,with excellence rate of 89.3％.Conclusion Biotype common handle artificial femoral head replacement is an effective method to allow early ambulation,reduce complications and improve quality of life in treatment of intertrochanteric fractures in the elderly.
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Objective To evaluate clinical efficacy of treating femoral intertrochanteric and subtrochanteric fractures combined with femoral shaft fractures using anatomic locking plate.Methods From January 2009 to June 2011,we treated 72 cases of femoral intertrochanteric and subtrochanteric fractures combined with femoral shaft fractures using anatomic locking plate.Sixty-four cases were followed up.There were 50 males and 14 female,with an average age of 42.8 years (range,21-79).All patients suffered from closed femoral unilateral fractures.The interval between injury and surgery was 2 h-16 d (average,4.6 d).All patients were followed up at regular interval.During the follow-up period,clinical and radiographic data were recorded.The clinical efficacy was evaluated with Harris hip function score.Results The mean operative time was 65 min (range,45-120 min); the mean blood loss was 210 ml (range,50-650 ml).All patients began to walk with crutches 3-35 d after surgery.During the follow-up period,no infection,deep vein thrombosis,screwed cut-out and implant failure occurred in all patients.Coxa vara with shortening deformity was noted in 2 cases,solid bone union was found in all the cases.The mean time of fracture healing was 5.2 months (range,3.6-10.5 months).According to Harris hip score,45 cases were classified as excellent,14 as good and 5 as fair,with excellent and good rate being 92.19％ (59/64).Conclusion Anatomic locking plate fixation provides stable fixation,with a high union rate and a minimal complication rate in treatment of intertrochanteric and subtrochanteric fractures combined with femoral shaft fracture.