Volume 13 · Issue 04 · 2010

Abstract：Objective: Management of mallet fractures is still a matter of discussion throughout the literature.For some authors, mallet fractures involving more than 1/3 of the articular surface and palmar subluxation of the distal phalanx require surgical treatment. In this study we retrospectively compared three different techniques for mallet fractures: Kirschner wire fixation with extension block pinning (EBP) of the distal interphalangeal joint, Kirschner wires used as joysticks (KWJ) and interfragrnentary miniscrews for open reduction and internal fixation (ORIF).Methods: Fifty-eight mallet fractures with palmar subluxation in 58 patients were treated with the aforementioned surgical techniques. Twenty mallet fractures in 20 patients 18 to 70 years old (average 42 years) were operated upon by EBP, 16 patients 22 to 56 years old (average 56 years) were operated upon using KWJ and 22 patients 22 to 54 years old (average 36 years) received ORIF. Follow-up time was 6 to 58 months (average 21 months). The following intraoperative parameters were considered: intraoperative time, number of Kirschner wires/screws and technical problems. Postoperative parameters included work absence and complications. The radiological evaluation was based on A-P and lateral views preoperatively and interviews at follow-up time. Bone union was defined by radiological evidence of bone trabeculae crossing the fracture site on at least one view. Clinical evaluation involved range of motion (ROM) test with a goniometer. Based on these measurements,a functional Crawford score was established.Results: All fractures healed. In the KWJ group,intraoperative time was shorter and total ROM was wider (72° vs 58° and 54°); in the ORIF group, return to work was faster (2.7 weeks vs 7.2 weeks and 6 weeks) but a little higher complication rate due to screw positioning has been found.Functional results as to total ROM, distal interphalangeal lag extension and Crawford classification were similar.Conclusions: We demonstrate the advantages of the use of the three techniques and bone consolidation in all cases with no signs of osteoarthritis. Screw fixation is more technically demanding (longer intraoperative time and more complications) but allows earlier mobilization and faster returning to work. EBP and KWJ techniques are faster to perform with no complications but require a careful management of the pin tracts. There is no statistically significant difference as to functional results。

Abstract：Objective: To evaluate the accuracy of computer-assisted pedicle screw installation and its clinical benefit as compared with conventional pedicle screw installation techniques. Methods: Total 176 thoracic pedicle screws placed in 42 thoracic fracture patients were involved in the study randomly, 20 patients under conventional fluoroscopic control (84 screws) and 22 patients had screw insertion under three dimensional (3D) computer-assisted navigation (92 screws). The 2 groups were compared for accuracy of screw placement, time for screw insertion by postoperative thincut CT scans and statistical analysis by x2 test. The cortical perforations were then graded by 2-mm increments: Grade Ⅰ (good, no cortical perforation), Grade Ⅱ (screw outside the pedicle <2 mm), Grade Ⅲ (screw outside the pedicle >2 mm).Results: In computer assisted group, 88 (95.65%) were Grade Ⅰ (good), 4 (4.35%) were Grade Ⅱ (<2mm), no Grade Ⅲ (>2 mm) violations. In conventional group, there were 14 cortical violations (16.67%), 70 (83.33%) were Grade Ⅰ (good),11 (13.1%) were Grade Ⅱ (<2 mm), and 3 (3.57%) were Grade Ⅲ (>2 mm) violations (P<0.001). The number (19.57%) of upper thoracic pedicle screws ( T1-T4 ) inserted under 3D computer-assisted navigation was significantly higher than that (3.57%) by conventional fluoroscopic control (P<0.001).Average screw insertion time in conventional group was (4.56 ±1.03) min and (2.54 ± 0.63) min in computer assisted group (P<0.001). In the conventional group, one patient had pleura injury and one had a minor dura violation.Conclusions: This study provides further evidence that 3D computer-assisted navigation placement of pedicle screws can increase accuracy, reduce surgical time, and be performed safely and effectively at all levels of the thoracic spine, particularly upper thoracic spine。

Abstract：Objective: To study the influences of head/neck ratio and femoral antetorsion on the safe-zone of operative acetabular orientations, which meets the criteria for desired range of motion (ROM) for activities of daily living in total hip arthroplasty (THA).Methods: Athree-dimensional generic, parametric and kinematic simulation module of THA was developed to analyze the cup safe-zone and the optimum combination of cup and neck antetorsion. A ROM of flexion≥ 120°, internal rotation ≥45° at 90° flexion, extension ≥30° and external rotation ≥ 40° was defined as the criteria for desired ROM for activities of daily living. The cup safe-zone was defined as the area that fulfills all the criteria of desired ROM before the neck impinged on the liner of the cup. For a fixed stemneck (CCD)-angle of 130°, theoretical safe-zones fulfilling the desired ROM were investigated at different general headneck ratios (GR=2, 2.17, 2.37, 2.61 and 2.92) and femoral anteversions (FA=0°, 10°, 20° and 30°).Results: Large GRs greatly increased the size of safezones and when the CCD-angle was 130°, a GR>2.37 could further increase the size of safe-zones. There was a complex interplay between the orientation angles of the femoral and acetabular components. When the CCD-angle was 130°, the optimum relationship between operative acetabular anteversion (OA) and femoral antetorsion (FA) could be estimated by the formula: OA=-0.80×FA+47.06, andthe minimum allowable operative acetabular inclination (OImin) would be more than 210.5×GR-2.255.Conclusions: Large GRs greatly increase the size of safe-zones and it is recommended that the GR be more than 2.37 so as to extend the acceptable range of error that surgeons cannot avoid completely during operation. As to the optimum operative acetabular inclination (OI), surgeons need to make a decision combining with other factors, including stress distribution, soft tissue and cup wear conditions, as well as patients' individual situations and demands. The data obtained from this study and the module of THA can be used to assist surgeons to choose and implant appropri-ate implants。

Abstract：Objective: To retrospectively analyse the clinical outcome of emergency treatment of senile intertrochanteric fractures with proximal femoral nail antirotation (PFNA).Methods: From September 2008 to March 2009, 35 senile patients with intertrochanteric fracture, aged from 65 to 92 years with an average age of 76.5 years, were treated with PFNA within 24 hours after injury. There were 10 type Ⅰ fractures, 19 type Ⅱ and 6 type Ⅲ according to upgraded Evans-Jensen classification system. All patients were complicated with osteoporosis, and 19 patients had preexisting internal medical diseases. According to the rating scale of disease severity by the American Society of Anesthesiologists (ASA), there were 9 grade Ⅰ, 14 grade Ⅱ, 8 grade Ⅲ, and 4 grade Ⅳ.Results: The duration for operation ranged from 45 to 73 minutes with an average of 57.6 minutes. The volume of blood loss during operation ranged from 50 to 120 ml with an average of 77.5 ml. Patients could ambulate 2-4 days after operation (mean 3.5 days). Hospital stay was 4-7 days (mean 5.3 days). Full weight bearing time was 10-14 weeks (mean 12.8 weeks). During hospitalization period, there was no regional or deep infection, hypostatic pneumonia, urinary tract infection and bedsore except for 2 cases of urine retention. All cases were followed up with an average period of 12.3 months, and bone healing achieved within 15-18 weeks (mean 16.6 weeks). No complications such as delayed union, coxa vara or coxa valga, screw breakage or backout occurred and only 2 cases had trochanter bursitis because of thin body and overlong end of the antirotated nail. According to the Harris grading scale, the results were defined as excellent in 21 cases, good in 9 cases and fair in 5 cases, with the excellent and good rates of 85.7%.Conclusion: The emergency treatment of senile intertrochanteric fracture with proximal femoral nail antirotation has the advantages of minimal invasion, easy manipulation,less blood loss, shorter length of stay, less complications,and the preliminary clinical effect is satisfactory。

Abstract：Objective: Although long bone fracture in children is not life-threatening, it may cause major disability, loss of working days and severe psychological distress. We conducted this study to determine the pattern of extremity fracture due to trauma in children.Methods: During one year in six general hospitals in Tehran, trauma patients who were hospitalized for more than 24 hours and sustained injuries within seven days before admission were included in the study. The records of children (≤16 years old) hospitalized in six general hospitals in Tehran due to trauma were reviewed prospectively.Results: During the study period, 1274 children had sustained extremity fractures. Male to female ratio was 3.6/1, with the mean age of (10.3±4.2) years. Falls and traffic crashes were the main causes of injuries, with the percentages of 57.3% and 37.1%, respectively. Simple fall (falling on the ground) consisted 60% of patients that sustained fall-related injuries. Pedestrians and bicycle riders comprised most of the cases that were injured due to traffic crashes. Of our cases, 56.8% sustained fractures in the upper extremities and 43.2% in the lower extremities. Forearm was the most common fracture site (34.1%). Comparing our results in preschool and school-age children, falls were the main cause of injuries in both groups, but fractures of lower extremities were significantly more common in preschool children.Conclusions:Improvement of physical condition of sidewalks and crossings in roads will be necessary for prevention of injuries. More attention to safety of home environment should be paid for control of preschools' injury at home. Education of children and adults is necessary to reduce injuries resulting from road traffic crashes。

Abstract：Objective: In pedicle screw fixation,the heads of monoaxial screws need to be directed in the same straight line to accommodate the rod placement by backing out during operation, which decreases the insertional torque and internal fixation strength. While polyaxial screws facilitate the assembly of the connecting rod, but its ball-in-cup locking mechanism reduces the static compressive bending yield strength as compared with monoaxial screws. Our study aimed to assess the mechanical performance of a modified pedicle screw.Methods: In this study, the tail of the screw body of the modified pedicle screw was designed to be a cylindershaped structure that well matched the inner wall of the screw head and the screw head only rotated around the cyclinder. Monoaxial screws, modified screws and polyaxial screws were respectively assembled into 3 groups ofvertebrectomy models simulated by ultra high molecular weight polyethylene (UHMWPE) blocks. This model was developed according to a standard for destructive mechanical testing published by the American Society for Testing Materials (ASTM F1717-04). Each screw design had 6 subgroups, including 3 for static tension, load compression and torsion tests, and the rest for dynamic compression tests. In dynamic tests, the cyclic loads were 25%, 50%, and 75% of the compressive bending ultimate loads respectively.Yield load, yield ultimate load, yield stiffness, torsional stiffness, cycles to failure and modes of failure for the 3 types of screws were recorded. The results of modified screws were compared with those ofmonoaxial and polyaxial screws.Results: In static tests, results of bending stiffness,yield load, yield torque and torsional stiffness indicated no significant differences between the modified and monoaxial screws (P>0.05), but both differed significantly from those ofpolyaxial screws (P<0.05). In dynamic compression tests,both modified and monoaxial screws showed failures that occurred at the insertion point of screw body into the UHMWPE block, while the polyaxial screw group showed screw body swung up and down the screw head because of loosening of the ball-in-cup mechanism.Conclusions: The modified screw is well-designed and biomechanically improved. And it can provide sufficient stability for segment fixation as monoaxial screws。

Abstract：Objective: To investigate the feasibility of posterior fixation with 3.5-mm pedicle screws in the atlantoaxial vertebrae of children.Methods: In this study, atlantoaxial vertebrae specimens were obtained from 10 cadavers of children aged 6-8 years. We measured the height and width of the C1 pedicle and the midportion of C1 lateral mass; the width of C1 posterior arch under the vertebral artery groove and the height of the external and internal one-third of this part; the external,internal height and the superior, middle, inferior width of the C2 pedicle (transverse foramen). Furthermore, computed tomography (CT) axial scan was performed on 20 agematched volunteers to obtain relative data of their atlantoaxial vertebrae. We measured the length and width of the C1 and C2 pedicles in the atlantoaxial cross-sectional plane. On CT workstation, we also measured the angles between the longitudinal axes of the atlantoaxial pedicles and the midsagittal plane.Results: For the cadaveric specimen group, the height and width of the C1 pedicle were (5.26±0.44) mm and (6.26±0.75) mm respectively. The height of the medial one-third of the C1 posterior arch under the vertebral artery groove was (4.07±0.24) mm. The external, internal height and superior,middle, inferior width of the C2 pedicle was (6.86±0.48) mm,(6.67±0.49) mm, (6.63 ±0.61 ) mm, (5.41±0.39) mm and (3.71±0.30) mm, respectively. For the volunteer group measured by CT scan, the height and width of the Ct pedicle were (5.47±0.34) mm and (6.63±0.54) mm respectively, while (6.59±0.51) mm and (5.13±0.42) mm of the C2 pedicle. The angles between the atlas, axis pedicles and the midsagittal plane were (9.60±1.32)° and (27.80±2.22)° respectively.Conclusion: It is feasible to place a 3.5-mm pedicle screw in the C1 and C2 pedicles of children aged 6-8 years old。

Abstract：Objective: To compare the clinical outcome of anterolateral minimally invasive approach versus conventional posterior approach for total hip replacement against femoral neck fractures in elderly patients.Methods: The retrospective study was carried out on 42 patients who suffered from displaced femoral neck fractures (19 cases of Garden type Ⅲ, 23 cases of Garden type Ⅳ) treated by total hip replacement via anterolateral minimally invasive approach or conventional posterior approach by the same experienced surgeon. The average age of the patients was 78.1 years (range: 65-89 years). They were divided into anterolateral mini-invasive group (22 cases) and posterior group (20 cases). The mean time of follow-up was 13 months (range: 6-36 months). The anterolateral approach described by Hardinge goes through between anterior 1/3 and posterior 2/3 of the gluteus medius muscle, reaching the femoral neck from anterior capsule. The traditional posterior approach described by Moore (Southern incision) goes through the insertions of short external rotation muscles,reaching the femoral neck from posterior capsule. The related variables under observation were length of incision,operation time, postoperative limp, length of hospital stay and bed stay and dislolcation rate.Results: The length of the skin incision varied between 7 cm and 12 cm with the anterolateral minimally invasive technique, compared to 15-22 cm in the conventional procedure. It took less time (average 15 minutes) to complete the anterolateral minimally invasive approach (72 min±15 min), compared with the conventional approach (87 min±10 min). The average Harris hip score was 91.23±10.20 inanterolateral approach, 90.03±11.05 in the posterior approach. The average length of hospital stay for patients with the anterolateral approach was (6.4±2.2) days (range:4-9 days), while that in posterior approach was (9.2 ±3.1)days (range: 6-13 days). The average length of bed stay was (3.4±1.1) days (range: 2-5 days) in anterolateral group and (6.2±2.8) days (range: 3-10 days) in posterior group. No patients in anterolateral group experienced dislocation. One (5%) hip in posterior approach had dislocation.Conclusions: Anterolateral mini-invasive approach can decrease trauma, operation time, length of hospital stay and bed stay and rehabilitation time. The stability and minimal muscular damage permit the acceleration of postoperative rehabilitation, which can subsequently reduce the perioperative risk in the treatment of femoral neck fractures in the elderly undergoing total hip replacement。

Abstract：Objective: To evaluate the interface characteristics of the new-designed locking plate (LP) and limited contact-dynamic compression plate (LC-DCP) and compare the fracture healing between LP and LC-DCP in a goat tibia fracture model.Methods: Eight-hole LP and LC-DCP were applied to fix flesh goat tibiae in a reproducible manner. The average pressure, force and interface contact area were calculated using Fuji prescale pressure sensitive film interposed among the plate and the bone and image analysis system. Eighthole LP and LC-DCP were applied to each tibia in a goat tibia fracture model. The fracture healing was evaluated by X-ray photography at postoperative 8 weeks. The goats were sacrificed at postoperative 12 weeks. Three-point bending test was conducted in the tibiae.Results: The interface contact of LP system was smaller than that ofLC-DCP (P<0.05), while interface contact force of LP system was higher than that of LC-DCP (P<0.05). Radiographs revealed that the fracture line disappeared in the LP group, while the fracture line was visible in DCP group at postoperative 8 weeks. At postoperative 12 weeks, the bending strength and bending load of fractured tibia were higher in LP group than in DCP group, respectively.Conclusion: The new-designed locking plate can significantly decrease the contact area on the bone interface,which further provides better fracture healing than conventional plates。

Abstract：Performing angiography in the prone position is a difficult technique; however it is useful in some emergency situation. We experienced a 60 years old male who was performed lipoma excision on his back in his family doctor's clinic. Since massive arterial bleeding could not be controlled with manual astriction, he transferred to our hospital in prone position with hemodynamic instability. Operating field was not kept because of massive bleeding; there-fore surgical treatment was impossible. We planed emer-gency arterial embolization (AE) in prone position. Hence we chose the left radial artery for vascular access. The left subclavicle arteriography showed many major and minor feeding arteries from left subclavicular and axillary arteries and a massive extravasation of the contrast medium. Three major feeding arteries were performed AE with gelatin sponge and steel coils. After AE, massive bleeding was controlled.He could discharge from our hospital on the 5th hospital day without any complication. Arterial embolization for lifethreatening bleeding from subcutaneous hypervascular tumor in the prone position is first report to our knowledge,and it is extremely rare. However we thought that this tech-nique is useful for patients who could not turn in the supine position, e.g. massive bleeding during renal biopsy and penetrating trauma from back。

Abstract：A 15 years old girl was found to have isolated trochlea fracture 10 weeks after an injury caused by a fall on her left elbow. Movement of the elbow was severely restricted. Radiographs showed a half moon-shaped and anterosuperiorly displaced osteochondral fragment. Medial approach capsulotomy of the elbow and excision of the intraarticular adhesions were done to expose the isolated trochlea fracture. Headless screws were used for fixation,combined with bone grafting. The follow-up showed union and excellent functional recovery of the elbow. Isolated trochlea fracture in adults is rare and usually associated with capitellar fractures and/or elbow dislocations. A neglected trochlea fracture is rarely reported in the English language literature to the best of our knowledge. Recognition of isolated trochlea fracture is vital to apprehend the pathomechanics of the injury and to devise a suitable treatment approach。

Abstract：Skin necrosis of the foot, oedema and lymphangitis from stonefish (Synanceia verrucosa) sting are complications well known for a long time and with potential long-term sequelae. Literature reports of stonefish envenomation give no specific reference on soft tissue management and surgical reconstruction. This is the first report describing a case of foot stonefish envenomation treated by vacuum-assisted closure therapy as an easy to use,accessible and simple adjuvant tool for management of large soft tissue necrosis。

Abstract：From July 2003 to July 2009, 15 cases of subdural hematoma with swirl signs were treated in our hospital and their clinical data were retrospectively analysed.The mortality was compared between these patients and those with typical acute subdural hematoma who were treated at the same time in our hospital. Among the 15 cases, full recovery was achieved in 4 cases, slight disability in 2, gave disability in 2 and death in 7 (46.7%). The mortality of these patients was conspicuously higher than that of typical subdural hematoma (14/83, 16.9%, P<0.01). Subdural hematoma with swirl signs is often suggestive of hazardous pathogenetic condition and early diagnosis and prompt surgical intervention is essential to reduce mortality。

Abstract：Subclavian artery thrombosis is a rare complication of clavicle fractures. We reported a 20-year-old man who was admitted to the emergency room after a road traffic accident. He was a pedestrian who was initially hit by a bus and after he fell down on the road, he was run over by a car. On evaluation, he was found to have multiple facial and rib fractures, distal right humerus and right clavicle fracture. Significantly, right radial pulse was absent. After further evaluation including Doppler studies and an angiography which revealed complete obstruction of right subclavian artery just distal to its 1st portion, the patient was urgently taken to the operation room. A midclavicular fracture was adjacent to the injured vessel. We established proximal and distal control, removed damaged part. After mobilizing the subclavian artery, an end-to-end anastomosis was made. Then open reduction and internal fixation of right distal humerus was performed. The rest of the postoperative course was unremarkable. To prevent complications of subclavian artery thrombosis, different treatment modalities can be used, including anticoagulation therapy,angioplasty, stenting and bypass procedures。