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 explore the failure cause of posterior approach orthopaedic operation of thoracolumbar hemivertebra, and to summary strategies of revision. Methods The cl inical data from 9 cases undergoing posterior approach orthopaedic operation failure of thoracolumbar hemivertebra between June 2003 and June 2008, were retrospectively analyzed. There were 5 males and 4 females with a median age of 12 years (range, 1 year and 10 months to 24 years). All malformations were identified as fully segmented hemivertebra from the original medical records and X-ray films, including 2 cases in thoracic vertebra, 5 cases in thoracolumbar vertebra, and 2 cases in lumbar vertebra. The preoperative scol iotic Cobb angle was (45.4 ± 17.4)°, and kyphotic Cobb angle was (29.8 ± 22.0)°. The reason of primary surgical failure were analyzed and spinal deformity was corrected again with posterior revision. Results All surgeries were finished successfully. The operation time was 3.0-6.5 hours (mean, 4.5 hours), and the perioperative bleeding was 400-2 500 mL (mean, 950 mL). All incisions healed by first intention; no infection or deep venous thrombosis occurred. Numbness occurred in unilateral lower extremity of 1 case postoperatively, and the symptom was rel ieved completely after treatment of detumescence and neural nutrition. All cases were followed up 12-30 months (mean, 18 months). No pseudoarthrosis and implant failure occurred. The X-ray films showed that the bone grafts completely fused within 8-14 months (mean, 11 months) after operation. The Cobb angles of scol iosis and kyphosis at 1 week after operation and the last follow-up were obviously improved when compared with preoperative ones, showing significant differences (P lt; 0.05). No obvious correction loss was observed either in coronal or sagittal plane. Conclusion The failure causes of posterior approach orthopaedic operation are hemivertebra processing, selection of fixation and fusion range, and selection of internal fixation. If the strategies of revision are made after the above-mentioned failure causes are considered, the cl inical results will be satisfactory.
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.
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.
Objective To discuss the therapeutic effect of distal fixed modular femoral prosthesis for the hip prosthesis revision. Methods Between August 2004 and May 2008, cementless modular femoral prosthesis was used for hip prosthesis revision in 21 cases. There were 9 males and 12 females, aged from 49 to 72 years (mean, 64.6 years). The timefrom revision to total hip arthroplasty was 2 to 18 years (mean, 11.7 years). The causes of revision included aseptic loosening in 19 cases (5 cases were periprosthetic femoral fracture), and deep infection in 2 cases. First revision was given in all patients. Preoperative Harris score was 41.8 ± 3.5; pain visual analogue score (VAS) was 7.62 ± 0.86. Results All patients achieved heal ing of incision by first intention, and no deep venous thrombosis and nerve injury occurred. Twenty-one cases were followed up 2 to 6 years with an average of 4.3 years. No prosthetic loosening or infection occurred. Bone ingrowth was observed around the implant during the follow-up period. At last follow-up, 2 cases had femoral stem subsidence without obvious hip pain and other symptoms, and no special treatment was given. Harris score was 82.7 ± 3.3 and VAS score was 0.19 ± 0.51 at last follow-up, showing significant differences when compared with those before operation (P lt; 0.05). Conclusion The short-term result of modular femoral prosthesis is satisfactory in hip prosthesis revision, and it can improve the hip function and rel ieve the pain greatly.
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.
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.
Objective To evaluate the effectiveness of prosthetic revision using custom-made long stem prosthesis and allograft-prosthesis composite (APC) for aseptic loosening after bone tumor resection. Methods Between January 2002 and June 2008, 14 patients with aseptic loosening after bone tumor resection were treated. There were 8 males and 6 females,aged 21-70 years (mean, 43.9 years). The locations were distal femur (8 cases), proximal femur (2 cases), and proximal tibia (4 cases). Pain of the affected l imb occurred after 6-31 years of prosthesis replacement and worsened when bearing and walking; 6 patients had shortened l imb. The functional results were assessed quantitatively according to the functional rating system of the Musculoskeletal Tumor Society (MSTS). The MSTS score was 16.36 ± 1.50 before revision. The X-ray films showed obvious prosthetic loosening and subsidence. The average time of symptom was 4.5 years (range, 3-9 years). In 7 patients having severe bone loss (the decrease of the thickness of cortical bone was more than 50%) and the prosthetic subsidence was more than 2 cm, the revision operation with the APC was performed; in 7 patients having less bone loss (the decrease of the thickness of cortical bone was less than 50%), the custom-made long stem prosthesis was performed. Results All wound healed by first intention. Two patients had temporary peroneal nerve paralysis and recovered after 3 months. All the patients were followed up 3.6 years on average (range, 2 years and 2 months-7 years) after revision. After revision, pain was rel ieved and the range of joint was improved. The MSTS score was 23.43 ± 2.56 at 12 months after revision showing significant difference when compared with the preoperative score (t=8.910, P=0.024). The X-ray films showed that lucency space l ine around stem cement in 2 patients at 12 months, and no prosthesis loosening and infection occurred. Conclusion The prosthetic revision after l imb salvage surgery with prosthesis for bone tumors was acceptable. The good functional results can be achieved by the revision with the APC or the custom-made long stem prosthesis according to the bone loss.
