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 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 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.
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 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 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．
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 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.
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.
ObjectiveTo conclude the revision reason of unicompartmental knee arthroplasty (UKA) using computer-assisted technology so as to provide reference for reducing the revision incidence and improving the level of surgical technique and rehabilitation. MethodThe relevant literature on analyzing revision reason of UKA using computer-assisted technology in recent years was extensively reviewed. ResultsThe revision reasons by computer-assisted technology are fracture of the medial tibial plateau, progressive osteoarthritis of reserved compartment, dislocation of mobile bearing, prosthesis loosening, polyethylene wear, and unexplained persistent pain. ConclusionsComputer-assisted technology can be used to analyze the revision reason of UKA and guide the best operating method and rehabilitation scheme by simulating the operative process and knee joint activities.