Objective To evaluate the strength of polyethylene l inercement interface when cementing a new linerinto a fixed acetabular cup in revision. Methods Twenty-five pairs of metal acetabular cups with polyethylene l iners were randomly divided into 5 groups: 1 group with standard locking device as control group (group A), other l iners were cemented into acetabular cups as 4 experimental groups. According to different intersection angles of metal acetabular cups with polyethylene liners and the polyethylene l iners with or without metal ball, the 4 experimental groups were no ball 0° group (group B), 0° group (group C), 10° group (group D), and 20° group (group E), metal acetabular cups intersected with polyethylene liners without metal ball in group B, with metal ball in groups C, D, and E, respectively. The lever-out biomechanical test reproduced in vivo failure mechanism was then performed to evaluate the lever-out failure strength of l iner-cement-metalcup interface. Results The values of l iver-out failure force were (626.68 ± 206.12), (915.04 ± 197.49), (449.02 ± 119.78),(814.68 ± 53.89), and (1 033.05 ± 226.44) N in groups A, B, C, D, and E, respectively, showing significant differences forcomparison among groups (F=8.989，P=0.000). The values of l iver-out failure force in groups B and E were significantlyhigher than that in group A (P lt; 0.05), but no significant difference was found between groups C, D and group A (P gt; 0.05).Conclusion Cementation of polyethylene l iner into a malposition shell meeting within 20° can provide enough fixed strength.
【Abstract】 Objective To review the progress in the treatment of bone defect by porous tantalum implant. Methods Recent l iterature was extensively reviewed and summarized, concerning the treatment method of bonedefect by porous tantalum implant. Results By right of their unique properties, porous tantalum implants have achievedvery good results in the treatment of certain types of bone defects. Conclusion Porous tantalum implants have their ownadvantages and disadvantages. If the case is meet to its indications, this method can obtain a good effect. Porous tantalum implants provide a new way for the cl inical treatment of bone defects.
OBJECTIVE To analyze the indications for revision surgery after limb salvage procedure of malignant bone tumor and summarize the experiences in revision surgery. METHODS From January 1994 to December 1997, 8 cases were re-operated after primary limb salvage procedure. The average survival period with no-tumor occurrence was 8 years. The common causes for the revision were traumatic osteoarthritis, fracture, and bone resorption. The main difficulties in revision were soft tissue contracture and limb discrepancy from limb shortening. RESULTS In this study, there was total hip replacement in 1 case, large segmental allograft for reconstruction of distal femur in 3 cases, total knee replacement upon composite of previously transplanted allograft in 3 cases, removing of intramedullary nail and re-internally fixed with intramedullary nail in 1 cases. The isotopic bone scan before the revision showed active bone metabolism in all 4 transplanted segmental allograft. The pathologic study of the transplanted allograft after revision confirmed new bone formation in allograft. The revision procedure reduced the pain, and improved the limb function. CONCLUSION The main causes of revision surgery after limb salvage procedure of malignant bone tumor are fracture of transplanted allograft segment or devitalized tumor segment, and poor function of the affected joint. Constrained knee prostheses with rotating hinges or semi-constrained ball-axis resurfacing knee prostheses improve the function of knee joint postoperatively.
Objective To analyze the effectiveness of transforaminal lumbar interbody fusion (TLIF) for failed back surgery syndrome (FBSS). Methods Between October 2003 and December 2007, 36 patients with FBSS were treated with TLIF. There were 19 males and 17 females with an average age of 52.6 years (range, 46-68 years) and an average disease duration of 1.6 years (range, 3 months-15 years). Of 36 patients, reoperation was performed in 25, 10 received 3 operations,and 1 had 5 operations. A total of 50 segments were involved in fusion, including L4, 5 in 12 cases, L5, S1 in 10 cases, L3, 4 and L4, 5 double segments in 8 cases, and L4, 5 and L5, S1 double segments in 6 cases. According to X-ray films, CT, and MRI examination, 12 patients were diagnosed as having lumbar instabil ity secondary to total laminectomy, 18 as having recurrence of lumbar disc protrusion, and 6 as having recurrence of lumbar spondylol isthesis. Results Dural rupture occurred in 1 case and was repaired by suturing without cerebrospinal fluid leakage was observed; 1 had deep incision infection of Staphylococcus; and 1 had transient single irritation sign because of hematoma formation and was cured after symptomatic treatment. The other incisions healed by first intention. No patients had permanent nerve injury or deterioration. Thirty-three cases were followed up 18-72 months (mean, 35.2 months). At 12 months, all the operated segments reached interbody fusion, and no breakage of screw or Cage dislocation occurred. Japanese Orthopaedic Association (JOA) scores showed significant difference (t=2.45, P=0.01) between before operation (14.2 ± 4.1) and 18 months after operation (23.9 ± 2.6). The rate of cl inical improvement was 90.9% (23 cases of excellent, 7 cases of good, 3 cases of acceptable). Conclusion The TLIF simpl ifies the manipulation of lumbar revision surgery and decreases the operation risk and the operative compl ications for the treatment of FBSS.
Objective To evaluate the medium-term results of uncemented acetabular revision with impacted deep frozen morsell ized allografts. Methods From April 1995 to December 2001, 58 cases (62 hips) were performed acetabularrevision by use of deep frozen morsel ized allograft firmly impacted into local ized defects as well as the entire acetabular cavity, followed by insertion of a uncemented cup with supplementary screw fixation. There were 32 males (34 hips) and 26 females (28 hips), with age of (49.6 ± 15.4) years old. Among 62 hips, 32 hips involved in left side and 30 hips involved in right side. The cause of revision was aseptic loosening of the cup in 56 hips, septic loosening of the cup in 3 hips, and polyethylene l iner dislodging with severe acetabular osteolysis in 3 hips. The average interval between the primary total hip arthroplasty and the revision was (10.1 ± 3.9) years. According to the American Academy of Orthopaedic Surgeons classification, 42 hips belonged to type II and 20 hi ps to type III acetabular defects. The cl inical and radiographic results were analyzed postoperatively. Results All wounds healed by first intention. No deep venous thrombosis and infection occurred postoperatively. All patients were followed up 6-13 years (average 8.1 years). The Harris score was improved from 61.1 ± 10.2 preoperatively to 92.0 ± 7.3 postoperatively, showing significant difference between preoperation and postoperation (P lt; 0.05). The results were excellent in 46 hips, good in 10 hips, fair in 4 hips, and poor in 2 hips, the excellent and good rate was 90.3%. The time for allograft incorporation was (12.5 ± 4.4) months after operation. The annual polyethylene l iner wear rate was (0.13 ± 0.09) mm. Linear and cavitary osteolysis was observed in 2 and 12 hips, respectively. Heterotopic ossification developed in 7 hi ps (11.3%); 3 hi ps were rated as grade I, 3 as grade II, and 1 as grade III according to Brooker classification. One cup underwent revision for asepticloosening and 2 were defined as radiographic failures. Kaplan-Meier survival rate of the cup was 94.2% ± 3.3% at 8 years after operation. Conclusion The combination of uncemented cup component with deep frozen morsel ized allografts seems to be a rel iable solution for restoring bone stock, relocating the hip center, and stabil izing the cup in acetabular revision, and provides favorable medium-term cl inical and radiographic results.
ObjectiveTo understand the inpatient classification and influence factors of hospitalization expenses, so as to provide basis for hospital management. MethodsThe diagnosis and treatment data of inpatients in a grade A tertiary hospital in 2013 were collected, the percentile method were used to describe the expenses distribution, the K-means clustering method was applied to classify the inpatients, the rank-sum test was utilized to analyze the differences of the costs among different groups, ICD-10 was applied to analyze the diseases distribution, and the median regression was used to analyze the influence factors. ResultsThere were 175 333 inpatients in total. The median of the expenses was 10 016.31 yuan RMB. The inpatients might be classified into seven groups with different expenses (P=0.0001). For inpatients who had no "blood transfusion cost", the top three factors of cost category were operation, laboratory test, examination; for who had "blood transfusion cost", the top three factors of cost category were blood transfusion, laboratory test, examination. There were 2 147, 2 182, 1 499, 1 301, 2 059, 22 and 14 kinds of diseases (ICD-10 four-digit code) respectively among the seven groups. The influence factors could be summarized into patient-related and diagnosis & treatment-related ones. ConclusionThe costs of operation, blood transfusion, laboratory test, and examination affect the inpatients classification greatly. The results could be of help to inform the admission of patients, the expense control and the disease management.
ObjectiveTo investigate the current problems and corresponding solutions regarding the use of antibiotic-impregnated cement spacer for the treatment of periprosthetic joint infection (PJI). MethodsA retrospective analysis was made on the clinical data of 27 patients with PJI who underwent two-stage revision with antibiotic-impregnated cement spacer between January 2001 and January 2013. There were 12 males and 15 females, with an average age of 62.7 years (range, 25-81 years). All arthroplasties were unilateral, including 19 hip PJI and 8 knee PJI. The mean duration from primary arthroplasty to PJI was 25 months (range, 3-252 months). After infection was controlled with the antibiotic-impregnated cement spacer combined with systematic antibiotics treatment, two-stage revision was performed. The effectiveness was evaluated. ResultsOne patient died of myocardial infarction at 2 days after surgery. Infection was controlled, and two-stage revision was successfully performed in 19 patients; deep venous thrombosis occurred in 1 of 3 patients who experienced hip spacer fractures, which was cured after conservative management. The spacers were removed and bacteria-sensitive antibiotics was used because of recurrent infections after the first-stage surgery in 7 patients; 3 patients gave up treatment because infection was not controlled, 4 patients received revision after infection was controlled. Twenty-three patients were followed up 1-5 years (mean, 2.3 years). The average Harris hip score and KSS score at 1 years after revision were significantly improved when compared with preoperative ones (P<0.05). In the 8 patients with gram-negative or fungus infection, 7 were found to have recurrent infection after the first-stage surgery; in the 12 patients with gram-positive infection, no recurrent infection was found. Failed treatment was observed in 1 patient with gram-positive and gram-negative infections and 2 with fungus infection, respectively. ConclusionAntibiotic-impregnated cement spacer has a satisfactory effectiveness for PJI. However, complication of spacer fracture should be noted, especially hip spacers. If the pathogen is gram-negative bacteria or fungus, the implanted spacer may increase the possibility of recurrent infection.
Objective To review the progress of the pedicle screw augmentation technique by bone cement. Methods Recent literature about the pedicle screw augmentation technique by bone cement was reviewed and analysed. The characters were summarized. Results Pedicle augmentation technique includes the augmentation of ordinary solid pedicle screw and hollow pedicle screw. Both types could increase the fixation strength and gain satisfactory clinical results. Bone cement leakage had a certain incidence rate, but most of cases were asymptom. Conclusion Bone cement augmentation of pedicle screw is an effective and safe internal fixation for poor bone condition.
Objective To compare the maximum pull-out strength of the upper il iac screw and lower il iac screw with and without polymethylmethacrylate (PMMA) augmentation, and to provide the experimental evidences for the rational use of il iacscrews. Methods Ten intact human il ium from 5 donated cadavers with formal in embalmed were selected. The bone mineral density (BMD) of L1-4 of each cadaver was measured with a dual energy X-ray absorptiometry. The screws placed in the upper and lower il iac column were named as the upper and lower il iac screw, respectively. Using 70 mm length and 7.5 mm diameter screws with and without PMMA augmentation, 4 il iac screw technique models were sequentially establ ished and tested as follows: upper il iac screw (group A), upper il iac screw with PMMA augmentation (group B), lower il iac screw (group C), and lower il iac screw with PMMA augmentation (group D). Each il ium was mounted on a material testing machine with its position similar to standing. Under 2 000 cycl ic compressive loadings of 100-300 N to the screw, the maximum pull-out strength of il iac screw was measured. Results The BMD value of the 5 human cadavers was (0.88 ± 0.06) g/cm2. All the il iac screws were inserted into the screw tracts accurately as expected. No screw penetrations of acetabulum or cortex was not observed through visual inspection. There was no “halo” ring sign surrounding any screw after the 2 000 cycle loading. The maximum pull-out strengths of groupsA, B, C, and D were (964 ± 250), (1 462 ± 266), (1 537 ± 279), and (1 964 ± 422) N, respectively. Group D exhibited the highest maximum pull-out strength among the 4 groups (P lt; 0.05). No significant difference was detected between groups B and C (P gt; 0.05); however, groups B, C showed higher maximum pull-out strength than group A (P lt; 0.05). Conclusion The lower il iac screw offers significantly higher fixation strength than the upper il iac screw; PMMA augmentation could effectively increase the fixation strength of il iac screws and therefore could be appl ied in the salvage of il iac screw loosening.
Objective To evaluate the clinical valueof the revision of total hip replacement(THR), to analyse the reason of the rev isions, and to discuss the main difficulties and measures to manage it.Methods From June 1998 to January 2002, 15 cases (15 hips) were revised on totalhip replacement. The reasons for revision in the cases were as follows:failure of primary operative techenique, loosening and sinking of the components, displacement of the prosthesis, erosion of the acetabulum, as well as fracture of the femoral stem. The main difficulties of the revision were:poor health condition of the patients; the remove of the prosthesis of the primary THR,especially the broken femoral stem and the cements; the loss of localbone. The measures to remove the broken femoral stem were described.ResultsAll cases were followed up 2.4 years on average: 2 patients died from heart disease and cerebrovascular disease respectively, while the good results were achieved in the others.No infection, dislocation, loosening, and other complications occurred. The good effects were related with following factors:mild degree of illness; no severe bone defect; most of the first femoral head replacement.Conclusion The revision of THRis a more difficult operation, so that the special instrument and equipment andoperative experience are required.