Objective To simulate anterosuperior instabil ity of the shoulder by a combination of massive irreparable rotator cuff tears and coracoacromial arch disruption in cadaveric specimens, use proximally based conjoined tendon transfer forcoracoacromial l igament (CAL) reconstruction to restrain against superior humeral subluxation, and investigate its feasibility and biomechanics property. Methods Nine donated male-adult and fresh-frozen cadaveric glenohumeral joints were applied to mimic a massive irreparable rotator cuff tear in each shoulder. The integrity of the rotator cuff tendons and morphology of the CAL were visually inspected in the course of specimen preparation. Cal ipers were used to measure the length of the CAL’s length of the medial and the lateral bands, the width of coracoid process and the acromion attachment, and the thickness in the middle, as well as the length, width and thickness of the conjoined tendon and the lateral half of the removed conjoined tendon. The glenohumeral joints were positioned in a combination of 30° extension, 0° abduction and 30° external rotation. The value of anterosuperior humeral head translation was measured after the appl ication of a 50 N axial compressive load to the humeral shaft under 4 sequential scenarios: intact CAL, subperiosteal CAL release, CAL anatomic reattachment, entire CAL excision after lateral half of the proximally based conjoined tendon transfer for CAL reconstruction. Results All specimens had an intact rotator cuff on gross inspection. CAL morphology revealed 1 Y-shaped, 4 quadrangular, and 4 broad l igaments. The length of the medial and lateral bands of the CAL was (28.91 ± 5.56) mm and (31.90 ± 4.21) mm, respectively; the width of coracoid process and acromion attachment of the CAL was (26.80 ± 10.24) mm and (15.86 ± 2.28) mm, respectively; and the thickness of middle part of the CAL was (1.61 ± 0.36) mm. The length, width, and thickness of the proximal part of the proximally based conjoined tendon was (84.91 ± 9.42), (19.74 ± 1.77), and (2.09 ± 0.45) mm, respectively. The length and width of the removed lateral half of the proximally conjoined tendon was (42.67 ± 3.10) mm and (9.89 ± 0.93) mm, respectively. The anterosuperior humeral head translation was intact CAL (8.13 ± 1.99) mm, subperiosteal CAL release (9.68 ± 1.97) mm, CAL anatomic reattachment (8.57 ± 1.97) mm, and the lateral half of the proximally conjoined tendon transfer for CAL reconstruction (8.59 ± 2.06) mm. A significant increase in anterosuperior migration was found after subperiosteal CAL release was compared with intact CAL (P lt; 0.05). The translation after CAL anatomic reattachment and lateral half of the proximally conjoined tendon transfer for CAL reconstruction increased over intact CAL, though no significance was found (P gt; 0.05); when they were compared with subperiosteal CAL release, the migration decreased significantly (P lt; 0.05). The translation of lateral half of the proximally conjoined tendon transfer for CAL reconstruction increased over CAL anatomic reattachment, but no significance was evident (P gt; 0.05). Conclusion The CAL should be preserved or reconstructed as far as possible during subacromial decompression, rotator cuff tears repair, and hemiarthroplasty for patients with massive rotator cuff deficiency. If preservation or the insertion reattachment after subperiosteal release from acromion of the CAL of the CAL is impossible, or CAL is entirely resected becauseof previous operation, the use of the lateral half of the proximally based conjoined tendon transfer for CAL reconstruction isfeasible.
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 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.
Although metal blocks have been widely used for reconstructing uncontained tibial bone defects, the influence of their elastic modulus on the stability of tibial prosthesis fixation remains unclear. Based on this, a finite element model incorporating constrained condylar knee (CCK) prosthesis, tibia, and metal block was established. Considering the influence of the post-restraint structure of the prosthesis, the effects of variations in the elastic modulus of the block on the von Mises stress distribution in the tibia and the block, as well as on the micromotion at the bone-prosthesis fixation interface, were investigated. Results demonstrated that collision between the insert post and femoral prosthesis during tibial internal rotation increased tibial von Mises stress, significantly influencing the prediction of block elastic modulus variation. A decrease in the elastic modulus of the metal block resulted in increased von Mises stress in the proximal tibia, significantly reduced von Mises stress in the distal tibia, decreased von Mises stress of the block, and increased micromotion at the bone-prosthesis fixation interface. When the elastic modulus of the metal block fell below that of bone cement, inadequate block support substantially increased the risk of stress shielding in the distal tibia and fixation interface loosening. Therefore, this study recommends that biomechanical investigations of CCK prostheses must consider the post-constraint effect, and the elastic modulus of metal blocks for bone reconstruction should not be lower than 3 600 MPa.
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 explore the techenique of fusing the reconstructed titanic plate, the C2 pedical screws, and the autogenous granulated cancellous bone graft in the occipitocervical region. Methods From April 2002 to January 2005, 19 patients aged 31-67 years with occipitocervical instability underwent the occipitocervical fusion using the reconstructed plate, C2 pedical screws, and autogenous granulated cancellous bone graft. Of the patients, 8 had complex occipitocervical deformity，8 had old atlantoaxial fracture and dislocation，2 had rheumatoid arthritis and anterior dislocation of the atlantoaxial joint, and 1 had cancer of the dentoid process of the axis． Results No complication occurred during and after operation．The follow-up for an average of 16 months in 19 patients showed that all the patients achieved solid bony fusion in the occipitocervical region．There was no broken plate, broken screw, looseness of the internal fixation or neurovascular injury. Conclusion The fixation of the C2 pedical screws with the reconstructed titanic plate is reliable, the insertion is easy, and the autogenous granulated cancellous bone graft has a high fusion rate, thus resulting in a satisfactory effect in the occipitocervical fusion.
ObjectiveTo evaluate the stability of the fixation technique for the crossed rods consisting of occipital plate and C2 bilateral lamina screws by biomechanical test.MethodsSix fresh cervical specimens were harvested and established an atlantoaxial instability model. The models were fixed with parallel rods and crossed rods after occipital plate and C2 bilateral laminae screws were implanted. The specimens were tested in the following sequence: atlantoaxial instability model (unstable model group), under parallel rods fixation (parallel fixation group), and under crossed rods fixation (cross fixation group). The range of motion (ROM) of the C0-2 segments were measured in flexion-extension, left/right lateral bending, and left/right axial rotation. After the test, X-ray film was taken to observe the internal fixator position.ResultsThe biomechanical test results showed that the ROMs in flexion-extension, left/right lateral bending, and left/right axial rotation were significantly lower in the cross fixation group and the parallel fixation group than in the unstable model group (P<0.05). There was no significant difference between the cross fixation group and the parallel fixation group in flexion-extension and left/right lateral bending (P>0.05). In the left/right axial rotation, the ROMs of the cross fixation group were significantly lower than those of the parallel fixation group (P<0.05). After the test, the X-ray film showed the good internal fixator position.ConclusionThe axial rotational stability of occipitocervical fusion can be further improved by crossed rods fixation when the occipital plate and C2 bilateral lamina screws are used.
Objective To discuss the effectiveness of operation technique for antero-medial rotatory instability (AMRI) of the knee joint caused by motorcycle. Methods Between June 2007 and December 2009, 32 cases of AMRI caused by motorcycle were treated. There were 28 males and 4 females with an average age of 35.5 years (range, 20-50 years). The interval between injury and surgery was 5-10 days (mean, 7 days). The anterior cruciate ligament (ACL) was injured at the attachment point of the condyles crest; the medial collateral ligament (MCL) was injured at central site in 19 cases, at medial condyles of femur in 10 cases, and at medial condyles of tibia in 3 cases, which were all closed injuries. The bone avulsion of condyles crest was fixed by steel wire and MCL was repaired. Results Red swelling and a little effusion occurred at the incision in 1 case, and the other incisions healed by first intention. Traumatic arthritis of the knee occured in 5 cases. Thirty-two cases were followed up 16-22 months (mean, 18.5 months). The X-ray examination showed that the fracture union time was 5-8 weeks (mean, 6 weeks) after operation. At last follow-up, the extension of knee joint was 0° and the flexion of the knee joint was 110-170° (mean, 155°). According to the synthetic evaluating standard of International Knee Documentation Committee, 24 cases were rated as A level, 6 cases as B, 1 case as C, and 1 case as D at last follow-up. Lysholm knee score was 85.93 ± 3.76 at last follow-up, which was significantly higher (t=53.785, P=0.000) than preoperative score 37.54 ± 3.43. Conclusion In patients with AMRI caused by motorcycle, steel wire is used to fix the bone avulsion of condyles crest and MCL should be repaired simultaneously as far as possible. And associating with the early postoperative functional exercise, the short-term effectiveness is satisfactory, but long-term effectiveness still need further follow-up observation.
It will cause hidden trouble on clinical application if the uroflowmeter is out of control. This paper introduces a scheme of uroflowmeter calibration device based on digital signal processor (DSP) and gear pump and shows studies of its feasibility. According to the research plan, we analyzed its stability, repeatability and linearity by building a testing system and carried out experiments on it. The flow test system is composed of DSP, gear pump and other components. The test results showed that the system could produce a stable water flow with high precision of repeated measurement and different flow rate. The test system can calibrate the urine flow rate well within the range of 9~50 mL/s which has clinical significance, and the flow error is less than 1%, which meets the technical requirements of the calibration apparatus. The research scheme of uroflowmeter calibration device on DSP and gear pump is feasible.
Objective To evaluate the effectiveness of anterior talofibular ligament repair in the treatment of lateral ankle stability and the effect of combined tarsal sinus syndrome on results. Methods Between December 2013 and October 2014, 47 cases of lateral ankle instability underwent anatomical repair of anterior talofibular ligament, and the clinical data were retrospectively analyzed. Of 47 cases, 32 had no tarsal sinus syndrome (group A); 15 had tarsal sinus syndrome (group B), arthroscopic debridement of tarsal sinus was performed at the same time. There was no significant difference in gender, age, disease duration, side, American Orthopaedic Foot and Ankle Society (AOFAS), Karlsson score, and Tegner movement function score between 2 groups (P>0.05). Results No early surgical complication of infection occurred, and primary healing of incision was obtained in 2 groups. The patients were followed up 20-31 months (mean, 26.0 months) in group A, and 20-31 months (mean, 24.7 months) in group B. Disappearance of ankle swelling, good joints movement, and recovery of normal walking were observed in all patients. At last follow-up, AOFAS score, Karlsson score, and Tegner movement function score were significantly improved when compared with preoperative ones in 2 groups (P<0.05), but no significant difference was found between 2 groups (P>0.05). No ankle instability recurrence was found during follow-up period. Conclusion The effectiveness of anatomical repair of anterior talofibular ligament in lateral ankle instability is satisfactory for patients with or without tarsal sinus syndrome.