Objective To investigate the relationship between the initial stabil ity and infected loosening of the total hip arthroplasty (THA) prosthesis. Methods From January 2000 to December 2008, 110 cases (110 hips) were treated with THA revision. Among them, 15 cases (15 hips) were confirmed infected loosening. There were 8 males and 7 females with anaverage age of 62 years (range 42-75 years). The infected signs were found from 6 months to 2 years after initial THA. All of them had Tsukayama type IV and late infection, including 6 cases of acetabular infected loosening (5 cases of one-stage and 1 case of two-stage acetabular revision), 7 cases of simple infected loosening of femoral prosthesis (4 cases of one-stage and 3 cases of twostage femoral prosthesis revision), and 2 cases of joint capsule infection and sinus without prosthesis loosening (debridement and continuous irrigation). Results All incisions healed by first intention. Fifteen patients were followed up for 12 to 36 months (average 24 months). In 13 cases of revision, postoperative X-ray films showed that femoral acetabular prostheses were in good position, and had no cl inical and imaging infective signs of loosening. In 2 cases of joint capsule infection, sinus recurred 6 months postoperation without hip joint pain, the function of weight-bearing and walking of hip joint was normal. Harris score increased from preoperative average of 42 to postoperative average of 85; the results were excellent in 4 cases, good in 7 cases, and fair in 4 cases. Conclusion The infection of THA may occur in the whole joint, half-joint or just in joint capsule. The initial stabil ity of the prosthesis would affect the long-term survival of the prothesis. If the prosthesis initial stabil ity is obtained, even if there are infective factors, infections would also be l imited.
Objective To evaluate the clinical importance of doublecontrast CTdiagnosis of traumatic anterior shoulder instability. Methods Forty-eight patients underwent double contrast CT scan. With the guide of CT scan, anterior arthrocentesis of the shoulder was performed and 4 ml of 76% urografin was injected into the joint and then 10 ml of filtrated air was injected. The patients wereexamined by SOMATOM CR Systematic CT. The results of double contrast CT of the 48 patients were divided into Ⅰ, Ⅱ and Ⅲ degree according to the CT results related to their injury history, clinical symptoms, signs and operation findings. Results The patients had no complaint after the CT examination exceptfor 3 patients, who had slight pain within 2 days after CT examination. The results of double contrast CT were as follow:Ⅰ degree: 9 patients, Ⅱ degree: 22 patients, and Ⅲ degree: 17 patients. All patients with Ⅰ degree injuries were treated with rehabilitation program. The patients with Ⅱ degree injuries were mainly treated withrehabilitation program, but took much longer time. The patients with Ⅲ degreeinjuries were suggested to be treated with surgery. Conclusion To divide the results of double contrast CT into Ⅰ，Ⅱ and Ⅲ degree not only reflects the severity of traumatic anterior shoulder instability but provides information for the treatment of the instability.
Objective To evaluate the biomechanical stability of a newly-designed Y type pedicle screw (YPS) in osteoporotic synthetic bone. Methods The osteoporotic synthetic bone were randomly divided into 3 groups (n=20). A pilot hole, 3.0 mm in diameter and 30.0 mm in deep, was prepared in these bones with the same method. The YPS, expansive pedicle screw (EPS), and bone cement-injectable cannulated pedicle screw (CICPS) were inserted into these synthetic bone through the pilot hole prepared. X-ray film examination was performed after 12 hours; the biomechanical stability of YPS, EPS, and CICPS groups was tested by the universal testing machine (E10000). The test items included the maximum axial pullout force, the maximum running torque, and the maximum periodical anti-bending. Results X-ray examination showed that in YPS group, the main screw and the core pin were wrapped around the polyurethane material, the core pin was formed from the lower 1/3 of the main screw and formed an angle of 15° with the main screw, and the lowest point of the inserted middle core pin was positioned at the same level with the main screw; in EPS group, the tip of EPS expanded markedly and formed a claw-like structure; in CICPS group, the bone cement was mainly distributed in the front of the screw and was dispersed in the trabecular bone to form a stable screw-bone cement-trabecular complex. The maximum axial pullout force of YPS, EPS, and CICPS groups was (98.43±8.26), (77.41±11.41), and (186.43±23.23) N, respectively; the maximum running torque was (1.42±0.33), (0.96±0.37), and (2.27±0.39) N/m, respectively; and the maximum periodical anti-bending was (67.49±3.02), (66.03±2.88), and (143.48±4.73) N, respectively. The above indexes in CICPS group were significantly higher than those in YPS group and EPS group (P<0.05); the maximum axial pullout force and the maximum running torque in YPS group were significantly higher than those in EPS group (P<0.05), but there was no significant difference in the maximum periodical anti-bending between YPS group and EPS group (P>0.05). Conclusion Compared with EPS, YPS can effectively enhance the maximum axial pullout force and maximum rotation force in the module, which provides a new idea for the design of screws and the choice of different fixation methods under the condition of osteoporosis.
Objective To evaluate the clinical results of bioabsorbable interference screw in knee ligament reconstruction. Methods From April 2002 to August 2004, 39 patients with knee ligament injury were treated, including 33 males and6 females with a median age of 25 years (15 to 65 years). The involved ligament included 29 anterior cruciate ligament of knee(ACL), 6 posterior cruciate ligament of knee(PCL)，4 combined ACL and PCL, 3 medial collateral or lateral collateral ligaments of knee point and 1 posterolateral complex injury of knee. All of patients underwent anatomic ligament reconstructions under arthroscopy or open surgery by autografts and fixation with bioabsorbable interference screw. Results All 34 patients were followed up 6 to 28 months (mean 13.7months). The patients were evaluated by Lysholm knee functional scales, the knee scores were 43.6±13.4 before operation and 85.4±16.3 after operation, showing significant difference (Plt;0.05). There was no limitation of rangeof motion and loosening of the screw. However, one case suffered from infection, and 3 cases suffered from effusion and synovitis after surgery and recovered after management. Conclusion Bioabsorbable interference screw fixation is a reliable method in knee ligament reconstruction and is effective to restore knee joint stability.
Objective To summarize the research about the stability of deep venous thrombosis (DVT) of the lower extremity in recent years. Methods The literatures about the stability of DVT of lower limbs at home and abroad in recent years were reviewed. Results There are few studies on the stability of DVT at home and abroad, which limited on the floating thrombus. Conclusion The stability of DVT can be effectively evaluated by SOMATOM Force CT (The third generation dual source CT).
Objective To investigate the effect of anteromedial coronoid facet fracture and lateral collateral ligament complex (LCLC) injury on the posteromedial rotational stability of the elbow joint. Methods The double elbows were obtained from 4 fresh adult male cadaveric specimens. Complete elbow joint (group A,n=8), simple LCLC injury (group B,n=4), simple anteromedial coronoid facet fracture (group C,n=4), and LCLC injury combined with anteromedial coronoid facet fracture (group D,n=8). The torque value was calculated according to the load-displacement curve. Results There was no complete dislocation of the elbow during the experiment. The torque values of groups A, B, C, and D were (10.286±0.166), (5.775±0.124), (6.566±0.139), and (3.004±0.063) N·m respectively, showing significant differences between groups (P<0.05). Conclusion Simple LCLC injury, simple anteromedial coronoid facet fracture, and combined both injury will affect the posteromedial rotational stability of the elbow.
Objective To evaluate of the valgus stability of the elbow after excision of the radial head, release of the medial collateral ligament (MCL), radial head replacement, and medial collateral ligament reconstruction.Methods Twelve fresh human cadaveric elbows were dissected to establish 7 kinds of specimens with elbow joint and ligaments as follow:①intact(n=12)； ②release of the medial collateral ligament(n=6)；③ excision of the radial head(n=6)；④excision of the radial head together with release of the medial collateral ligament(n=12)；⑤radial head replacement(n=6)；⑥medial collateral ligament reconstruction(n=6)；⑦radial head replacement together with medial collateral ligament reconstruction(n=12). Under two-newton-meter valgus torque, and at 0, 30, 60, 90 and 120 degrees of flexion with the forearm in supination, the valgus elbow laxity was quantified: All analysis was performed with SPSS 10.0 software.Results The least valgus laxity was seen in the intact state and its stability was the best. The laxity increased after resection of the radial head. The laxity was more after release of the medial collateral ligament than after resection of the radial head (Plt;0.01). The greatest laxity was observed after release of the medial collateral ligament together with resection of the radial head, so its stability was the worst. The laxity of the following implant of the radial head decreased. The laxity of the medial collateral ligament reconstruction was as much as that of the intact ligament (Pgt;0.05). The laxity of the radial head replacement together with medial collateral ligament reconstruction became less.Conclusion The results of this studyshow that the medial collateral ligament is the primary valgus stabilizer of the elbow and the radial head was a secondary constraint to resist valgus laxity.Both the medial collateral ligament reconstruction and the radial head replacement can restore the stability of elbow. If the radial head replacement can notbe carried out, the reconstruction of the medial collateral ligament is acceptable.
Objective To investigate the effectiveness of surgical treatment for single-level degenerative lumbar instabil ity (DLI) by comparing traditional open transforaminal lumbar interbody fusion (TLIF) with minimally invasive TLIF. Methods Between March 2007 and May 2009，87 patients with single-level DLI were treated by traditional open TLIF (group A, n=45) and by minimally invasive TLIF (group B, n=42), respectively. There was no significant difference in gender, age, disease duration, segment level, combined diseases of lumbar spine, or the proportion of uni- and bilateral symptom between 2groups (P gt; 0.05). The indexes of surgical trauma，systemic inflammatory response, cl inical outcomes, and aravertebral muscle injury were compared between 2 groups. Results Operation was performed successfully in all patients. The patients were followed up 2.9 years on average in group A and 2.8 years on average in group B. The incision, blood loss, and postoperative drainage in group B were significantly less than those in group A (P lt; 0.05), but the operation time in group B was significantly longer than that in group A (P lt; 0.05). There were significant differences (P lt; 0.05) in C-reactive protein, leucocyte count, and creatine kinase MM between 2 groups at 24 hours postoperatively as well as in C-reactive protein at 6 days postoperatively; group B was superior to group A. At last follow-up, the Oswestry disabil ity index (ODI) and visual analogue score (VAS) were significantly improved when compared with the preoperative scores in 2 groups (P lt; 0.05). There were significant differences in ODI and back pain VAS score (P lt; 0.05), but no significant difference in leg pain VAS score (P gt; 0.05) between 2 groups. At last follow-up, no low back pain occurred in 8 and 18 cases, mild in 25 and 18 cases, moderate in 9 and 6 cases, and severe in 3 and 0 cases in groups A and B, respectively, showing that low back pain was significantly l ighter in group B than in group A (Z= —2.574, P=0.010). At last follow-up, the atrophy ratio of multifidus muscle was 37% ± 13% in group A and was 15% ± 7% in group B, showing significant difference (t=12.674, P=0.000). The multifidus muscle atrophy was rated as grade I in 18 and 44 sides, as grade II in 42 and 32 sides, and as grade III in 30 and 8 sides in groups A and B, respectively, showing significant difference (Z= — 4.947, P=0.000). Conclusion Both traditional open TLIF and minimally invasive TLIF are the effective treatments for single-level DLI. Minimally invasive TLIF has less surgical trauma, sl ighter postoperative systemic inflammatory response, less paravertebral muscle injury, and lower incidence of postoperative back pain, but it has longer operation time.
Objective To review the progress in the features, early cl inical outcomes, and cl inical appl ication of axial lumbar interbody fusion (AxiaLIF) for the minimally invasive treatment of lumbosacral degenerative diseases. Methods The l iterature about the features, early cl inical outcomes, and cl inical appl ication of AxiaLIF for the minimally invasive treatment of lumbosacral degenerative diseases in recent years was reviewed. Results Almost 9 000 procedures performed globally in recent years, AxiaLIF has shown its safety and effectiveness because of high fusion rates, short hospital ization days, and less iatrogenic compl ications in comparison with standard fusion procedures. ConclusionPostoperative long-term outcomes, biomechanics stabil ity, and extended appl ication of AxiaLIF still need a further study,though it suggests an original minimally invasive treatment of lumbosacral degenerative diseases.
In the evaluation of tear film stability based on corneal topography, a pretreatment algorithm for tear film video was proposed for eye movement, eyelash reflection and background interference. First, Sobel operator was used to detect the blur image. Next, the target image with highlighted ring pattern was obtained by the morphological open operation performed on the grayscale image. Then the ring pattern frequency of the target image was extracted through the Hough circle detection and fast Fourier transform, and a band-pass filter was applied to the target image according to the ring pattern frequency. Finally, binarization and morphological closed operation were used for the localization of the ring pattern. Ten tear film videos were randomly selected from the database and processed frame by frame through the above algorithm. The experimental results showed that the proposed algorithm was effective in removing the invalid images in the video sequence and positioning the ring pattern, which laid a foundation for the subsequent evaluation of tear film stability.