Objective To compare the short-term effectiveness between primary cemented and uncemented total hip arthroplasty (THA) for osteonecrosis of the femoral head (ONFH) after renal transplantation. Methods The clinical data were retrospectively analyzed from 18 patients (21 hips) with ONFH after renal transplantation undergoing cemented THA in 11 cases (13 hips) (cemented group) and uncemented THA in 7 cases (8 hips) (uncemented group) between February 2005 and February 2012. There was no significant difference in gender, age, disease duration, ONFH stage, preoperative Harris score, and bone density between 2 groups (P gt; 0.05). Postoperative complications were observed in 2 groups; the hip function was assessed based on Harris scores; X-ray film was used to observe the prosthetic situation. Results All the wounds healed by first intention. The patients were followed up 6-77 months (mean, 46 months) in the cemented group, and 4-71 months (mean, 42 months) in the uncemented group. Femoral prosthesis infection occurred in 1 case (1 hip) respectively in each group; hip dislocation, femoral prosthesis loosening, and acetabular prosthesis loosening occurred in 1 case (1 hip) of the cemented group, respectively. At last follow-up, the incidences of postoperative complications and revision rate of the cemented group were 30.7% (4/13) and 23.1% (3/13) respectively, which were significantly higher than those of the uncemented group [12.5% (1/8) and 0 (0/8)] (P=0.047, P=0.040). Harris score was significantly increased to 94.1 ± 3.7 in the uncemented group and 90.0 ± 4.2 in the cemented group, showing significant differences compared with the preoperative scores in 2 groups (P lt; 0.05), but there was no significant difference between 2 groups (t=1.815, P=0.062). Postoperative X-ray films showed that the initial position of the prosthesis was satisfactory. At last follow-up, the bone fixation, fibrous stability, and loosening of the femoral prosthesis and loosening of acetabular prosthesis occurred in 9 hips, 3 hips, 1 hip, and 1 hip of the cemented group, respectively; bone fixation of the femoral prosthesis and stability of acetabular prosthesis were observed in all hips of the uncemented group. There was no heterotopic ossification in 2 groups. Conclusion Uncemented THA after renal transplantation can obtain satisfactory short-term effectiveness, and uncemented THA is better than the cemented THA; however, the middle- and long-term effectivenesses need further observation．
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 summarize the progress of Masquelet technique to repair bone defect. Methods The recent literature concerning the application of Masquelet technique to repair bone defect was extensively reviewed and summarized. Results Masquelet technique involves a two-step procedure. First, bone cement is used to fill the bone defect after a thorough debridement, and an induced membrane structure surrounding the spacer formed; then the bone cement is removed after 6-8 weeks, and rich cancellous bone is implanted into the induced membrane. Massive cortical bone defect is repaired by new bone forming and consolidation. Experiments show that the induced membrane has vascular system and is also rich in vascular endothelial growth factor, transforming growth factor β1, bone morphogenetic protein 2, and bone progenitor cells, so it has osteoinductive property; satisfactory results have been achieved in clinical application of almost all parts of defects, various types of bone defect and massive defect up to 25 cm long. Compared with other repair methods, Masquelet technique has the advantages of reliable effect, easy to operate, few complications, low requirements for recipient site, and wide application. Conclusion Masquelet technique is an effective method to repair bone defect and is suitable for various types of bone defect, especially for bone defects caused by infection and tumor resection.
Objective To investigate the biomechanical properties of porous bioactive bone cement (PBC) in vivo and to observe the degradation of PBC and new bone formation histologically. Methods According to the weight percentage (W/ W, %) of polymethylmethacrylate (PMMA) to bioglass to chitosan, 3 kinds of PBS powders were obtained: PBC I (50 ︰ 40 ︰ 10), PBC II (40 ︰ 50 ︰ 10), and PBC III (30 ︰ 60 ︰ 10). The bilateral femoral condylar defect model (4 mm in diameter and 10 mm in depth) was established in 32 10-month-old New Zealand white rabbits (male or female, weighing 4.0-4.5 kg), which were randomly divided into 4 groups (n=8); pure PMMA (group A), PBC I (group B), PBC II (group C), and PBC III (group D) were implanted in the bilateral femoral condylar defects, respectively. Gross observation were done after operation. X-ray films were taken after 1 week. At 3 and 6 months after operation, the bone cement specimens were harvested for mechanical test and histological examination. Four kinds of unplanted cement were also used for biomechanical test as control. Results All rabbits survived to the end of experiment. The X-ray films revealed the location of bone cement was at the right position after 1 week. Before implantation, at 3 months and 6 months after operation, the compressive strength and elastic modulus of groups C and D decreased significantly when compared with those of group A (P lt; 0.05), but no significant difference was found between groups C and D (P gt; 0.05); the compressive strength at each time point and elastic modulus at 3 and 6 months of group B decreased significantly when compared with those of group A (P lt; 0.05). Before implantation and at 3 months after operation, the compressive strength and elastic modulus of groups C and D decreased significantly when compared with those of group B (P lt; 0.05); at 6 months after operation, the compressive strength of group C and the elastic modulus of group D were significantly lower than those of group B (P lt; 0.05). The compressive strength and elastic modulus at 3 and 6 months after operation significantly decreased when compared with those before implantation in groups B, C, and D (P lt; 0.05), but no significant difference was found in group A (P lt; 0.05). At 3 months after operation, histological observation showed that a fibrous tissue layer formed between the PMMA cement and bone in group A, while chitosan particles degraded with different levels in groups B, C, and D, especially in group D. At 6 months after operation, chitosan particles partly degraded in groups B, C, and D with an amount of new bone ingrowth, and groups C and D was better than group B in bone growth; group A had no obvious change. Quantitative analysis results showed that the bone tissue percentage was gradually increased in the group A to group D, and the bone tissue percentage at 6 months after operation was significantly higher than that at 3 months within the group. Conclusion According to the weight percentage (W/W, %) of PMMA to bioglass to chitosan, PBCs made by the composition of 40 ︰ 50 ︰ 10 and 30 ︰ 60 ︰ 10 have better biocompatibility and biomechanical properties than PMMA cement, it may reduce the fracture risk of the adjacent vertebrae after vertebroplasty.
Objective To investigate the biomechanics of a novel injectable calcium phosphate cement (CPC) composited by poly (lactic-co-glycolic acid) (PLGA) combined with double-screw fixation in repairing Schatzker II type tibial plateau fracture, so as to provide the mechanical basis for the clinical minimally invasive treatment. Methods Ten matched pairs of proximal tibia specimens were harvested from 10 elderly cadavers to prepare Schatzker II type tibial plateau fracture model. Fracture was fixed by forcing injection of CPC (experimental group) or autologous cancellous bone (control group) combined with double-screw fixation. The samples underwent axial compression on MTS 858 material testing machine to measure the load-displacement, the maximum load, and compressive stiffness. Results The novel CPC had good injectable property at room temperature, which could fill in bone defect fully and permeated into the surrounding cancellous bone. The average bone mineral density of tibial metaphysis was (0.639 ± 0.081) g/cm2 in the experimental group and (0.668 ± 0.083) g/ cm2 in the control group, showing no significant difference (t=1.012, P=0.331). The maximum load in the experimental group [(4 101 ± 813) N] was significantly higher than that in the control group [(692 ± 138) N] (t=3.932, P=0.001). The compressive stiffness was (1 363 ± 362) N/mm in the experimental group and was (223 ± 54) N/mm in the control group, showing significant difference (t=3.023, P=0.013). Conclusion The novel CPC can effectively restore the biomechanical properties of tibilal plateau in repairing Schatzker II type tibial plateau fracture by means of forcing injection combining with double-screw fixation. It could be used as an effective bone substitute in the clinical application.
Objective To investigate the effectiveness of two-stage revision of infected total knee arthroplasty (TKA) using an antibiotic-impregnated articulating cement spacer. Methods The clinical data were analyzed from 23 patients (23 knees) undergoing two-stage revision for late infection after primary TKA between January 2007 and December 2009. There were 15 males and 8 females, aged from 43 to 75 years (mean, 65.2 years). Infection occurred at 13-52 months (mean, 17.3 months) after TKA. The time interval between infection and admission ranged from 15 days to 7 months (mean, 2.1 months). One-stage operation included surgical debridement and removal of all knee prosthesis and cement, then an antibiotic-impregnated articulating cement spacer was implanted. The re-implantation of prosthesis was performed after 8-10 weeks when infections were controlled. The American Hospital for Special Surgery (HSS) score and Knee Society Score (KSS) were used to compare the function of the knee between pre- and post-revision. The rate of infection control and complication were analyzed. Results All incisions healed primarily. Re-infection occurred in 2 cases after two-stage revision, and infection was controlled in the other 21 cases, with an infection control rate of 91.3%. The patients were followed up 2-5 years (mean, 3.6 years). The HSS score was increased from 60.6 ± 9.8 at pre-revision to 82.3 ± 7.4 at last follow-up, the KSS score was increased from 110.7 ± 9.6 at pre-revision to 134.0 ± 10.5 at last follow-up, all showing significant differences (P lt; 0.01). Radiographs showed that prosthesis had good position with no loosening, fracture, or periprosthetic radiolucent. Conclusion Two-stage revision using an antibiotic-impregnated articulating cement spacer is an effective method to control infected TKA and to restore the function of affected knee.
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.
Objective To investigate the in vivo degradable properties of new calcium phosphate cement (CPC) containing poly lactic-co-glycolic acid (PLGA) so as to lay a foundation for the future clinical application. Methods A novel CPC containing PLGA (CPC/PLGA) was prepared according to a ratio of 45% dicalcium phosphate anhydrous ∶ 45% partially crystallized calcium phosphates ∶ 10% PLGA. Thirty-two adult New Zealand rabbits (weighing 2.2-3.0 kg, male or female in half) were divided into the experimental group (n=17) and the control group (n=15). The bone defect models of the bilateral femoral condyles (4.5 mm in diameter and 1.5 cm in depth) were made by drilling hole. Defect at the right side was repaired with CPC/ PLGA in the experimental group and with CPC in the control group, while defect at the left side was not treated as blank control. The general condition of rabbits was observed after operation; the histological observation and bone histomorphometric analysis were performed at 2, 4, 8, 16, and 24 weeks; and scanning electronic microscope (SEM) observation was performed at 8 and 16 weeks after operation. Results All rabbits survived to the end of experiment. The histological observation showed: CPC/PLGA degraded gradually, and the new-born bone trabecula ingrew; bone trabeculae became rough and b; and CPC/PLGA almost biodegraded at 24 weeks in the experimental group. The CPC degradation was much slower in the control group than in the experimental group. The total bone tissue percentage was 44.9% ± 23.7% in the experimental group, and 25.7% ± 10.9% in the control group, showing significant difference between 2 groups (t=3.302, P=0.001); and the bone tissue percentage showed significant difference between 2 groups at 8, 16, and 24 weeks (P lt; 0.05). The results of SEM observation showed that the pore size was 100-300 μm at 8 weeks after operation, new-born bone trabecula grew into the pores and combined bly with residual cement in the experimental group. Conclusion Novel CPC/PLGA has good in vivo degradable properties, and it can be an ideal bone substitute in future clinical application.
Objective To investigate the diagnosis and effectiveness of improved percutaneous kyphoplasty (PKP) for patients with thoracolumbar metastatic tumors, who could not tolerate anesthesia and open operation. Methods Between September 2009 and September 2010, 16 patients with thoracolumbar metastatic tumors underwent improved PKP. Of 16 patients, 7 were male and 9 were female with an average age of 64.5 years (range, 60-73 years). All patients had vertebralmetastasis tumor. The disease duration was 3-6 months with an average of 4 months. The visual analogue scale (VAS) score was 8.9 ± 0.8. No spinal cord compression and nerve root compression was observed. The involved vertebrae included T7 in 1 case, T8 in 1, T12 in 1, L2 in 2, L3 in 2, L4 in 3, T1, 2 in 1, T3, 4 in 1, T7, 8 in 1, T11, 12 in 1, T7-L1 in 1, and T12-L4 in 1. Nine patients had vertebral compression fracture with a vertebral compression rate below 75%. Results All patients were successfully performed PKP. There was no serious adverse reactions in cardiopulmonary and brain vascular systems and no perioperative death. The biopsy results showed that all were metastatic adenocarcinoma. All patients were followed up 9-18 months mean, 14 months). Complete pain rel ief was achieved in 14 cases and partial rel ief in 2 cases 6 months after operation according to World Health Organization criterion, with a pain-rel ief rate of 87.5%. The VAS score was 1.8 ± 0.6 at 6 months postoperatively, showing significant difference when compared with the preoperative score (P lt; 0.05). Two patients had cement leakages in 3 vertebrae with no symptoms at 6 months postoperatively. During follow-up, 12 patients died and the others survived with tumor. Conclusion For patients with thoracolumbar metastatic tumors who can not tolerate anesthesia and open operation, improved PKP has the advantages such as minimal invasion, high diagnostic rate, and early improvement of pain in the biopsy and treatment. It can improve patient’s qual ity of l ife in the combination of radiotherapy or chemotherapy.
Objective To evaluate the effectiveness of Confidence high viscosity bone cement system and postural reduction in treating acute severe osteoporotic vertebral compression fracture (OVCF). Methods Between June 2004 and June2009, 34 patients with acute severe OVCF were treated with Confidence high viscosity bone cement system and postural reduction. There were 14 males and 20 females with an average age of 72.6 years (range, 62-88 years). All patients had single thoracolumbar fracture, including 4 cases of T11, 10 of T12, 15 of L1, 4 of L2, and 1 of L3. The bone density measurement showed that T value was less than —2.5. The time from injury to admission was 2-72 hours. All cases were treated with postural reduction preoperatively. The time of reduction in over-extending position was 7-14 days. All patients were injected unilaterally. The injected volume of high viscosity bone cement was 2-6 mL (mean, 3.2 mL). Results Cement leakage was found in 3 cases (8.8%) during operation, including leakage into intervertebral space in 2 cases and into adjacent paravertebral soft tissue in 1 case. No cl inical symptom was observed and no treatment was pearformed. No pulmonary embolism, infection, nerve injury, or other complications occurred in all patients. All patients were followed up 12-38 months (mean, 18.5 months). Postoperatively, complete pain rel ief was achievedin 31 cases and partial pain refief in 3 cases; no re-fracture or loosening at the interface occurred. At 3 days after operation and last follow-up, the anterior and middle vertebral column height, Cobb angle, and visual analogue scale (VAS) score were improved significantly when compared with those before operation (P lt; 0.05)；and there was no significant difference between 3 days and last follow-up (P gt; 0.05). Conclusion Confidence high viscosity bone cement system and postural reduction can be employed safely in treating acute severe OVCF, which has many merits of high viscosity, long time for injection, and easy-to-control directionally.