【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 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.
Objective To study the effect of all-coated long stem prosthesis associated with allograft in revision total hip replacement (THR). Methods From January 1997 to January 2004, 20 patients with non-infectious loosened implant after primary THR were treated. There were 12 males and 8 females with a mean age of 65 years (58-77 years). The average period between primary THR and revision THR was 12 years (3-18 years). According to classification of Paprosky, there were10 cases of type II, 6 cases of type IIIA, 3 cases of type IIIB and 1 case of type IV. All-coated long stem prosthesis was used in all cases. Impacting bone grafting was done in 12 cases and impacting bone grafting associated with cortical strut grafting in 8 cases. The mean amount of morsel ized bone was 20 g (5-35 g), the length of cortical bone was 10-22 cm. Results All the incisions got heal ing by first intension. All patients were followed up for an average period of 36 months (16-48 months). Dislocation occurred at 5 days after operation and was cured with closed reduction and traction in 1 case. There was significant difference (P lt; 0.05) in the mean Harris score between preoperation (50.0 ± 2.3) and postoperation (90.0 ± 2.5). The X-ray checking showed that continuous radiolucent l ine of 3 mm occurred in 1 case, prosthesis subsidence of 5 mm and 7 mm in 2 cases and that no bone absorption was observed. Seven cases of cortical bone grafting union was achieved within 3 years except 1 case of cortical bone un-union. Conclusion It can obtained the initial stabil ization of prosthesis to use all-coated long stem prosthesis associated with allograft in revision THR to treat femur bone defect after THR. The short-term effects of the cl inical and X-ray checking are satisfactory, but future effect is to be observed.
From 1974 to 1991, two hundred and sixty-four cases of hip replacement were performed. These cases composed of 150 cases of artificial femoral head prosthesis replacement and 114 cases of total hip replacement. Fifteen cases were revised after the first replacement in 7.4 years average (5-16 years). The revision rate was 5.7%. The causes of revision were loose or subside of prosthesis, wear and tear of acetabulum, dislocation of artificial hip joint, etc, which caused pain and dysfunction. The revision cases were followed up for 4.7 years average with good result. To prevent revision, The medully canal shonld not be too wide and in osteoporosis cases, bone cement was suggested to apply. The chondrium of acetabulum should be removed completely.
fter total hip replacement ,massive bone defect occured freqently due to wearing and loosening of the prcathesis.The use of deep-freezing allograft to su pport a new implant was an attractive solution. Deep-freezing decreased the immune antigenicity of the transplanted allograft.From 1972 to 1990. the deep-freezing allografts were used in rcvision total hip replacement in 212 cases,in which 187 cases(198 hips) were followed-up for over 1 year.The general effective rate was 85%....
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 main reasons of acetabular component initial instabil ity after primary total hip arthroplasty (THA) and to disscuss the prevention and management. Methods The cl inical data were retrospectively analyzed from 19 patients undergoing revision for acetabular component initial instabil ity after primary THA between January 2003 and June 2010. There were 11 males and 8 females, aged from 55 to 79 years (mean, 67.2 years). The locations were lefthip in 9 cases and right hip in 10 cases. The cementless hip prosthesis was used in 12 cases and cement hip rosthesis in 7 cases. The revisions were performed at 3 weeks to 6 months after primary THA. The reasons of early failure were analyzed. Both the coverage rate of acetabulum-bone and the Harris hip score were compared between pre- and post-revision. Results The main reason of acetabular component initial instabil ity after primary THA may be unsuitable treatment of acetabulum, improper selection of acetabular component, and incorrect place angle of acetabular component. Sciatic nerve palsy occurred in 1 case and recovered at 7 weeks after revision. Sl ight fracture of the acetabulum in 1 case and healed at 3 months after revision. All incisions healed by first intention. No infection, vessel injury, displacement of acetabular component, or deep vein thrombosis occurred. The patients were followed up 11-73 months (mean, 28 months). At last follow-up, no acetabular component instabil ity was observed. The coverage rate of acetabulum-bone was increased from 67.9% ± 5.5% before revision to 87.7% ± 5.2% after revision, showing significant difference (t=11.592，P=0.003). The Harris hip score at last follow-up (84.4 ± 4.6) was significantly higher than that at pre-revision (56.5 ± 9.3) (t=11.380，P=0.005). Conclusion Detailed surgical plan, proper choice of component, correct place angle and elaborative planning, and proficient surgical skill are necessary to achieve the initial stability of acetabular component in THA．
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 evaluate the surgical skill, cause of revision, compl ications, prosthetic survival and postoperative function in revision of custom-made tumor prosthesis replacement of knee joint. Methods The cl inical data of 33 patients who received prosthetic revision surgery between June 2002 and June 2007 were reviewed. There were 17 malesand 16 females with an average age of 33.1 years (range, 16-67 years). The pathological diagnosis included 17 osteosarcomas, 11 giant cell tumors, 2 mal ignant fibrous histocytomas, 1 chondrosarcoma, 1 synovial sarcoma, and 1 l iposarcoma. The involved locations were distal femur in 22 cases and proximal tibia in 11 cases. The average interval between first prosthetic replacement and revision surgery was 45.3 months (range, 6-180 months). The reason for revision included local recurrence in 2 cases, deep infection in 8 cases, aseptic loosening in 7 cases, peri prosthetic fracture in 1 case, prosthetic stem fracture in 6 cases, and prosthetic hinge failure in 9 cases. Six patients with deep infection received two-stage revision surgery, while the other 27 patients received one-stage revision. Cemented prostheses were used in all patients. Allograft prosthetic composite and revisions were used in 2 patients who had deficit of diaphysis for stem fixation. Results In 17 patients who received both primary prosthetic replacement and revision, the operative time was (149.8 ± 40.5) minutes and (189.9 ± 43.8) minutes, and the blood loss was (605.2 ± 308.0) mL and (834.1 ± 429.9) mL for primary prosthetic replacement and revision, respectively; all showing statistically significant differences (P lt; 0.05). The mean time of follow-up was 45.1 months (range, 12-76 months). Heal ing between allograft and host bone was obtained in 2 patients with allograft prosthetic composite and revision after 1.5 years and 2 years, respectively. After revision surgery, 3 patients died of lung metastasis after 12-24 months, and other 3 patients havinglung metastasis were al ive with disease. Nine (30%) compl ications occurred in 30 patients who were al ive at last follow-up. The compl ications included wound infection in 2 patients, deep infection in 5 patients, mechanical problems in 2 patients. Prosthetic failure occurred in 7 patients (23.3%). The 5-year survival rate of revised prosthesis was 68.6%. The Musculoskeletal Tumor Society (MSTS) score at 6 months after revision (73.6% ± 14.4%) was significantly improved (P lt; 0.01) when compared with before revision (57.1% ± 10.6%). Conclusion The main reasons for revision of custom-made tumor prosthesis of knee joint were mechanical problems and deep infection. Although revision surgery of knee is relatively compl icated and has some compl ications, a functional l imb could be maintained in most tumor patients.