[Study on the characteristics of biology force line of proximal femur based on structural topology optimization].

Internal fixator is usually adopted in the treatment of bone fractures. In order to achieve anatomical reduction and effective fixation of fractures, the placement of internal fixators should comply with the biology force line of the bone and adapt to the specific anatomical morphological characteristics of the cortical bone. In order to investigate the distribution characteristics and formation regularity of biology force line and cortical thickness of human bone, three-dimensional model of proximal femur is established by using three-dimensional reconstruction technique in this paper. The normal physiological stress distribution of proximal femur is obtained by finite element analysis under three kinds of behavior conditions: one-legged stance, abduction and adduction. The structural topology optimization method is applied to simulate the cortex of the proximal femur under the combined action of three kinds of behavior conditions, and the anatomic morphological characteristics of the proximal femur are compared. The distribution trend of biology force line of proximal femur and the characteristics of cortex are analyzed. The results show that the biology force lines of bone structure and the morphological characteristics of cortex depend on the load of human activities. The distribution trend of biology force line is related to the direction of trabecular bone and the ridge trend and firmness of cortex when bone is loaded physiologically. The proposed analytical method provides a solution to determine the biology force line of bone and the distribution characteristics of cortex. The conclusions obtained may guide the reasonable placement of internal fixator components of fracture.

Application of a Shape-Memory Alloy Concentrator in Displaced Patella Fractures: Technique and Long-Term Results.

Operative treatment is usually recommended in displaced patella fractures. Several techniques have been advocated for internal fixation of patella fractures. Despite the relatively good clinical outcomes that have been demonstrated in many studies, postoperative morbidities such as fixation failure, nonunion, infection, and knee stiffness are not uncommon. We present a new alternative treatment technique for displaced patellar fractures. Between April 1995 and May 2005, we used the Nitinol Patella Concentrator (NTPC) to treat 156 consecutive patients with displaced patellar fractures. Injuries arose from vehicular accidents in 56 (35.9%) cases, direct falls onto the knee in 85 (54.5%) cases, and sports injuries in 15 (9.6%) cases. The mean patient age was 46.3 years (range, 25-77 years). Clinical assessments were made using the Böstman knee score and the MOS SF-36 questionnaire (Medical Outcomes Study 36-item short-form health survey), which were both recorded at the final follow-up visit. The mean follow-up was 7.3 years (range, 6-17 years). At the final follow-up, the Böstman knee scores were excellent in 88 cases (28-30), good in 55 (20-27), and unsatisfactory in 13 (<20). According to the MOS SF-36 evaluation, the average score was 84.5 (range, 62-91). Treatment of patellar fracture with the NTPC not only may serve as an effective and rigid fixation method in multifragmented displaced and inferior pole fractures, but also may provide continuous concentrative compression during the osseous healing process. Thus, use of the NTPC may help restore the functional integrity of the extensor mechanism and permit early rehabilitation with a lower incidence of postoperative complications.

[BIOMECHANICS STUDY ON ACETABULAR POSTERIOR WALL FRACTURE].

OBJECTIVE: To study the experimental biomechanics of acetabular posterior wall fractures so as to provide theoretical basis for its clinical treatment. METHODS: Six formalin-preserved cadaveric pelvises were divided into groups A and B (n=3). The fracture models of superior-posterior wall and inferior-posterior wall of the acetabulum were created on both hips in group A; fractures were fixed with two interfragmentary screws and a locking reconstruction plate. The fracture models of superior-posterior wall of acetabulum were created on both hips in group B; fractures were fixed with two interfragmentary screws and a locking reconstruction plate at one side, and with acetabular tridimensional memory fixation system (ATMFS) at the other side. The biomechanical testing machine was used to load to 1 500 N at 10 mm/min speed for 30 seconds. The displacement of superior and inferior fracture sites was analyzed with the digital image correlation technology. RESULTS: No fracture or internal fixation breakage occurred during loading and measuring; the displacement valuess of the upper and lower fracture lines were below 2 mm (the clinically tolerable maximum value) in 2 groups. In group A, the displacement values of the upper and lower fracture lines at superior-posterior wall fracture site were significantly higher than those at inferior-posterior wall fracture site (P < 0.01), and the displacement values of the upper fracture line were significantly higher than those of lower fracture line (P < 0.01) in two fracture types. In group B, the displacement values of the upper and lower fracture lines at the side fixed with screws and a locking reconstruction plate were similar to the values at the side fixed with ATMFS, all being close to 2 mm; the displacement values of the upper fracture line were significantly higher than those of lower fracture line (P < 0.05) in two fixation types. CONCLUSION: The actual biomechanical effect of the superior-posterior wall of acetabulum is much greater than that of the inferior-posterior wall of acetabulum and they should be discriminated, which might be the reasons of reduction loss, femoral head subluxation, and traumatic arthritis during follow-up.

Posterior trochanteric osteotomy in acetabular fractures for 32 cases.

The aim of this study is to explore the method and clinical outcome of posterior trochanteric osteotomy in acetabular fractures. From January 2000 to January 2008, 32 cases of acetabular fractures involving the dome of acetabulum underwent posterior trochanteric osteotomy for a better exposure and internal fixation with acetabular tridimensional memory fixation system. 28 cases (16 men and 12 women, mean age 39.9 years, range 16-73 years) were followed up with an average of 48.9 months (range of 19-95 months) and four were lost during follow up. Of 28 cases, 19 were fresh fractures and 9 were old fractures. The reduction was evaluated with Matta criteria. Clinical evaluation was based on modified Merle d'Aubigne and Postel scoring. Motor strength of the abductors was evaluated according to the Medical Research Council grading system. Ectopic ossification was classified according to Brooker criteria. Anatomical reduction was achieved in 17 cases and satisfied reduction in 10 patients. Poor reduction happened in an old fracture. All acetabular fractures got a direct bone union and no displacement and deep infection occurred. All osteotomies healed within 3.5 months without any nonunion, proximal migration of the greater trochanter, loosing or broken of instrumentation, and deep infection. Two superficial infections were healed with a regular dressing. Two patients underwent removal of implants from greater trochanter because of irritation. The strength of the abductors was of Grade 3/5 in two patients, Grade 4/5 in five patients, and normal in the rest. Clinical scoring was excellent to good in 84 %. Ectopic ossification occurred in five patients, grade 1 in two patients, grade 2 in two, and grade 3 in one. But function of hip joint was not seriously affected. Posterior trochanteric osteotomy can provide an adequate exposure of the dome of acetabulum without the associated complications like nonunion, proximal replacement, and weak of the abductors which often occur with standard oblique osteotomy.

[Missed diagnosis of hiding posterior marginal fracture of ankle with pronation-external rotation type and its treatment].

OBJECTIVE: To analyze causes of missed diagnosis of hiding post-malleolar fractures in treating ankle joint fractures of pronation-external rotation type according to Lauge-Hansen classification and assess its medium-term outcomes. METHODS: Among 103 patients with ankle joint fracture of pronation-external rotation type treated from March 2002 to June 2010,9 patients were missed diagnosis,including 6 males and 3 females,with a mean age of 35.2 years old (ranged, 18 to 55 years old) . Four patients were diagnosed during operation, 2 patients were diagnosed 2 or 3 days after first surgery and 3 patients came from other hospital. All the patients were treated remedially with lag screws and lock plates internal fixation. After operation,ankle joint function was evaluated according to American Orthopaedic Foot and Ankle Society (AOFAS). RESULTS: All the 9 patients were followed up, and the duration ranged from 14 to 30 months (averaged, 17 months). No incision infection was found, and all incision healed at the first stage. At the latest follow-up, AOFAS was 83.0 +/- 4.4, the score of 4 patients diagnosed during operation was 85.0 +/- 2.9, and the score of 5 patients treated by secondary operation was 81.0 +/- 5.3. All the patients got fracture union observed by X-ray at a mean time of 2.2 months after operation. There were no complications such as internal fixation loosing, broken and vascular or nerve injuries. CONCLUSION: Ankle joint fracture of pronation-external rotation type may be combined with hiding post-malleolar fractures. So to patients with ankle joint fracture of pronation-external rotation type, lateral X-ray should be read carefully, and if necessary, CT or MRI examination should be performed. If adding lateral X-ray examination after reduction of exterior and interior ankle joint fixation, the missed diagnosis may be avoided.

Comparative study of comminuted posterior acetabular wall fracture treated with the Acetabular Tridimensional Memory Fixation System.

BACKGROUND: Posterior wall fractures are one of the most common acetabular fractures. However, only 30% of these fractures involve a single large fragment, and comminuted acetabular posterior wall fractures pose a particular surgical challenge. The purpose of this study was to compare outcomes between patients who received fixation for comminuted posterior wall fracture using the Acetabular Tridimensional Memory Fixation System (ATMFS) and patients who underwent fixation with conventional screws and buttress plates (Plates group). METHOD: Between April 2003 and May 2007, 196 consecutive patients who sustained a comminuted posterior wall fracture of acetabulum were treated with ATMFS or conventional screws and buttress plates. Operative time, fluoroscopy time, blood loss, and any intra-operative complications were recorded. Plain AP and lateral radiographs were obtained at all visits (Matta's criteria). Modified Merle d' Aubigne-Postel score, and Mos SF-36 score were compared between groups. RESULTS: Fifty patients were included in the analysis with 26 in the ATMFS group and 24 in the Plates group. The mean follow-up time was 57.5 months, ranging from 31 to 69 months. All patients had fully healed fractures at the final follow-up. There was no difference in clinical outcomes or radiological evaluations between groups. CONCLUSION: Patients with comminuted posterior wall fractures of the acetabulum treated with the ATMFS or conventional screws and buttress plate techniques achieve a good surgical result. Both techniques are safe, reliable, and practical. Use of the ATMFS technique may reduce blood loss and improve rigid support to marginal bone impaction. The use ATMFS may need additional support when fractures involve the superior roof.

[Advanced bone graft combined with locking compression plate for the treatment of middle and distal tibia nonunion].

OBJECTIVE: To explore methods of treating middle and distal tibia nonunion with the treatment of advanced bone graft combined with locking compression plate. METHODS: From January 2011 to December 2012, 12 patients with middle and distal tibia nonunion were treated with advanced bone graft combined with locking compression plate. Among patients, there were 8 males and 4 females aged from 20 to 69 with an average of 47 years old. The time from first injuries to bone nonunion was from 9 months to 5 years, avergaed 19 months. Four cases were treated with external fixation, 6 cases were treated with plate fixation, 2 cases of 12 patients occurred broken of plate and nail. Eleven patients were non-infective bone nonunion and 1 patient was infective bone nonunion. Preoperative X-ray and CT showed all patients had sequestration and formation of ossified bone with different degrees. Operative time, blood loss, wound healing were observed, fracture healing time was evaluated by postoperative X-ray. Johner-Wruhs scoring standards was used to evaluate ankle joint function after operation at 10 months. RESULTS: Operative time ranged from 90 to 185 min with an average of (125.00±20.15) min; blood loss ranged from 225 to 750 ml with an average of (415.00±120.00) ml. All patients were followed up from 10 months to 2.5 years with an average of 1.5 years. Postoperative X-ray showed bone union was formed around fracture after operation at 4 months in all patients, 3 cases obtained bone healing within 6 months after operation, 9 cases obtained from 8 to 12 months. No infection, injury of nerve and vessles, and broken of plate and nail were ocurred. According to Johner-Wruhs scoring at 10 months after operation, 10 cases obtained excellent results, 1 good and 1 moderate. CONCLUSION: Advanced bone graft combined with locking compression plate, which can build fracture multi-point supporting based on full compression of bone nonunion to get effective fixation, is an effective method in treating middle and distal tibia nonunion.

[Anatomic measurements and quantitative analysis of posterior acetabular wall].

OBJECTIVE: To explore morphological character and clinical significance of superior-posterior acetabular wall by anatomically measuring and quantitatively analyzing thickness of posterior acetabular wall, then provide a theoretical reference for clinical treatment of acetabular fracture. METHODS: Fifteen adult formalin-preserved cadaveric pelvises (8 males and 7 females) were used for this investigation. Excess soft tissue was removed and the whole acetabular posterior walls were marked with "angle" sector method and the thickness was measured with caliper in different levels of the different split points. The measurement results were validated and analyzed statistically. RESULTS: At 5 mm away from acetabular rim, the average thickness of superior-posterior acetablar wall fluctuated between (6.47±0.61) mm and (7.43±0.71) mm; the average thickness of inferior-posterior acetabuluar wall fluctuated between (5.62±0.51) mm and (6.33±0.61) mm; the average thickness of acetabular roof fluctuated between (7.71±0.74) mm and (8.27±0.99) mm. There was no statistical difference between average thickness of superior-posterior wall of acetabulum and inferior-posterior wall of acetabulum (P>0.05), but the average thickness of acetabular roof was significantly larger than superior-posterior acetabular wall (P<0.05). At 10 mm away from the acetabular rim, the average thickness of superior-posterior acetabular wall fluctuated between (8.81±0.67) mm and (13.35±0.89)mm; the average thickness of inferior-posterior acetabular wall fluctuated between (7.02±0.63) mm and (7.66±0.69) mm; the average thickness of acetabular roof fluctuated between (14.46±0.97) mm and (17.05±1.35) mm. Comparatively, the average thickness of superior-posterior acetabular wall was significantly larger than inferior-posterior wall of acetabulum (P<0.05), and the average thickness of acetabular roof was significantly larger than superior-posterior acetabular wall (P<0.01). At 15 mm away from the acetabular rim, the average thickness of superior-posterior acetabular wall fluctuated between (12.08±0.78) mm and (19.84±1.03) mm; the average thickness of inferior-posterior acetabular wall fluctuated between (10.17±0.76) mm and (11.12± 0.77) mm; the average thickness of acetabular roof fluctuated between (23.23±1.12) mm and (26.01±1.53) mm. Comparatively, the average thickness of superior-posterior wall of acetabulum was significantly larger than inferior-posterior acetabular wall (P<0.01), and the average thickness of acetabular roof was significantly larger than superior-posterior acetabular wall (P< 0.01). CONCLUSION: The thickness of entire acetabular posterior edge revealed an increasing tendency from inferior-posterior wall to the superior-posterior wall to acetabular roof. And this trend became more obvious with increasing distance away from acetabular rim. Therefore, the superior-posterior acetabular wall could not only maintain the stability of hip joint but also bear loading.

Application of Ni-Ti alloy connector for the treatment of comminuted coronal plane supracondylar-condylar femoral fractures: a retrospective review of 21 patients.

BACKGROUND: Our preliminary retrospective study assessed outcomes after the use of Ni-Ti arched shape-memory connector (ASC) combined with partially threaded cancellous screws (PTCS) to repair coronal plane supracondylar-condylar femoral fractures. METHODS: Twenty-one patients (16 men and 5 women) with a mean age of 34.1 years (range, 28 to 44 years) with coronal plane supracondylar and condylar fractures of the distal femur were included in this study. Each patient underwent open reduction and internal fixation using the ASC and PTCS. Active functional exercises with restricted weight bearing were initiated the first postoperative day. A gradual increase in weight bearing status and range of motion was permitted and subjects progressed to full weight bearing by 8 weeks. Surgical time, blood loss, postoperative knee range of motion, American Knee Society Scores (KSS), and postoperative complications were assessed. RESULTS: The mean surgical time was 75 mins (range, 45 to 100 mins) and average blood loss was 105 ml (range, 35 to 130 ml). Mean follow-up was 65 months (range, 22 to 90 months). No subjects demonstrated evidence of osteonecrosis or arthritis at the final follow-up. The mean KSS was excellent (≥85) in 8 subjects, good (70-84) in 11 subjects, and fair (60-69) in 2 subjects. The mean active range of motion of knee flexion at final follow-up was 100 degrees (range, 85 to 110 degrees). CONCLUSIONS: ASC combined with PTCS can serve as an effective means for managing comminuted femoral fractures that extend from the condyle to the supracondylar region. However, further prospective comparative studies and biomechanical analyses are needed to evaluate long-term outcomes using these materials.

Massive heterotopic ossification associated with late deficits in posterior wall of acetabulum after failed acetabular fracture operation.

BACKGROUND: Heterotopic ossification is a common postoperative complication of acetabular fracture. However, functionally significant heterotopic ossification with associated late bone defects in the posterior wall of the acetabulum is rare and challenging to treat. When heterotopic ossification is a late complication of failed acetabular fracture operation, it is disabling and may only be treated by THA. THA is highly susceptible to premature failure in young and active patients and may require numerous revisions. CASE PRESENTATION: This article describes a 40-year-old man with massive heterotopic ossification associated with late bone defects in the posterior wall of the acetabulum after a failed acetabular fracture operation. The primary fracture type was a 62-A2.3 fracture according to the AO/OTA Classification.Surgical excision and anatomical reconstruction of the acetabular wall using heterotopic ossific bone were performed 10 months after the fracture repair. Postoperatively, indomethacin was administered for prophylaxis against recurrence of heterotopic ossification, and hip range of motion was progressively increased. At 5 years and 6 months follow-up, the patient's pain was relieved and hip function had recovered. Though radiography and CT showed minimal subchondral cysts and mild joint-space narrowing, there was no evidence of graft resorption, progressive posttraumatic osteoarthritis or necrosis of the femoral head. CONCLUSION: To the authors' knowledge, this is the first case of such a challenging condition. Although it is an extremely rare case, it provides an attractive option for avoiding THA, as the long-term follow-up shows a satisfactory outcome.

[Treatment of comminuted fracture of tibial plateau with ni-ti shape memory alloy bow-teeth screws combined with locking plate internal fixation].

OBJECTIVE: To assess the clinical effects of Ni-Ti shape memory alloy bow-teeth screws combined with locking plate internal fixation in treating comminuted fracture of tibial plateau. METHODS: From January 2003 to December 2008, 17 patients with comminuted fracture of tibial plateau were treated with Ni-Ti shape memory alloy bow-teeth screws and locking plate internal fixation. There were 9 males and 8 females with an average age of 33.7 years old (ranged, 23 to 48 years). All fractures were fresh and injured time less 3 weeks and 2 patients with common peroneal nerve injury. According to Schatzker typing, type V was in 1 case and type VI was in 16 cases. RESULTS: All patients were followed up from 10 to 22 months with an average of 18 months and all incisions healed in one stage. At 3 to 12 weeks after operation, knee joint function of 16 cases arrived to the level of uninjured side and 1 case was poor in flexed function. All fractures obtained union at 3 to 5 months after operation, and internal fixtures were removed at 1 year after operation and no reduction lossing or refracture occurred. At final follow-up, no bone block shifting, internal fixture loosening and breakage was found. According to the standard of Xushanding's knee joint function, 9 cases got excellent results, 4 good, 4 fair. CONCLUSION: The design of Ni-Ti shape memory alloy bow-teeth screws is adapt to irregular anatomic structure of comminuted fractures of tibial plateau,it can continuously pressurize and promote bone healing. Multi drop lockedup may avoid wide-ranging stripping local soft tissue, and form three-dimension fixation after combined with locking plate internal fixation, can effective recover anatomic structure of fracture. So Ni-Ti shape memory alloy bow-teeth screws combined with locking plate internal fixation is an effective method in treating comminuted fracture of tibial plateau.

[Application of Ni-Ti patellar concentrator combined with Herbert screw and wirerope for the treatment of comminuted patellar inferior pole fractures].

OBJECTIVE: To evaluate the surgical techniques and clinical effect of Ni-Ti patellar concentrator combined with Herbert screw and wirerope in treating comminuted patellar inferior pole fractures. METHODS: From March 2008 to June 2010,34 patients with comminuted patellar inferior pole fracture were treated with Ni-Ti patellar concentrator combined with Herbert screw and wirerope. Of them, there were 19 males and 15 females with an average age of 38.6 years old(ranged from 22 to 75). Early functional exercise was guided postoperatively and the patients were regularly followed up and their outcomes were assessed. RESULTS: All patients were followed up with an average of 13.5 months (ranged,7 to 20). All fractures healed. According to Böstman Clinical Rating System, the average score was 28.43 +/- 2.34,and excellent results in 21 cases,good in 13 cases and no poor case. CONCLUSION: Ni Ti patellar concentrator combined with Herbert screw and wirerope for the treatment of comminuted patellar inferior pole fracture is an effective method and of great value to clinical application.

Modified posterior soft tissue repair for the prevention of early postoperative dislocation in total hip arthroplasty.

PURPOSE: Dislocation following total hip arthroplasty (THA) with the posterior approach has been quite a common and bothering complication. Previous researches suggest that careful repair of the posterior structures significantly reduces this risk. The purposes of the present study were to describe a modified posterior soft tissue repair procedure in THA using a suture anchor (TwinFix Ti 5.0, Smith & Nephew, Andover, MA) and evaluate the early postoperative dislocation rate. METHODS: From July 2004 to June 2008, 220 consecutive primary total hip arthroplasties were performed using the modified surgical approach. The average age in the group was 46.4 years (range from 21 to 90) at the time of the procedure. The rate of postoperative hip dislocation, as well as any signs of complications related to the technique, has been observed and analyzed in this study. RESULTS: There was no postoperative dislocation following primary THA in 220 cases, and no signs of complications related to the technique, such as greater trochanteric fractures and sciatic nerve palsy, have been noted in any of the cases at their most recent follow-up. CONCLUSIONS: These initial results demonstrate that the modified repair in THA using the suture anchor can serve as an effective and reliable mean for prevention of early postoperative dislocation.

The use of a structural free iliac crest autograft for the treatment of acetabular fractures.

INTRODUCTION: Bone and cartilage deficits in the posterior acetabular wall are severe complications resulting from the unsuccessful management or delayed treatment of acetabular fracture. This potentially disastrous condition cannot be treated reliably with the use of reconstruction plates and screws alone. Therefore, this technical report describes a modified anatomical reconstruction method that uses a structural iliac crest autograft and an acetabular tridimensional memory alloy fixation system (ATMFS) to treat late-stage deficits in the posterior wall of the acetabulum. This paper also describes a clinical study of 22 patients with an average of 6.3 years follow-up to evaluate the clinical outcomes of this method. METHODS: Twenty-two patients, who had an acetabular reconstruction between January 2000 and December 2011 that used a structured free iliac crest autograft to treat late-stage bone and cartilage deficits in the posterior acetabular wall were followed annually with clinical and radiographic evaluations. The average age of the patients was 36.4 years at the time of the procedure, and the average time of follow-up was 6.3 years. RESULTS: None of the patients in this study lost reduction after surgery, and there were no cases of implant failure. Radiographic analysis using Matta's X-ray evaluation criteria were excellent in eleven cases, good in eight, and fair on three. The Merle D'Aubigné and Postel clinical outcomes at the final follow-up were as follows: seven cases were excellent, ten cases were good, three cases were fair and two cases were poor. CONCLUSIONS: The use of a modified iliac crest grafting and ATMFS fixation, as a biological method to reconstruct the acetabulum anatomically may offer better congruence of the joint surface and may ensure good hip joint stability during early postoperative exercise. The medium to long-term results of this method are encouraging.

Design and application of nickel-titanium olecranon memory connector in treatment of olecranon fractures: a prospective randomized controlled trial.

PURPOSE: We carried out this study to test the efficacy of the olecranon memory connector (OMC) in olecranon fractures. METHODS: We designed a prospective randomised controlled trial involving 40 cases of olecranon fractures. From May 2004 to December 2009, 40 patients with olecranon fractures were randomly assigned into two groups. Twenty patients were treated with OMC, while another 20 patients were fixed with locking plates in our hospital. The DASH score, MEP score, range of motion and radiographs were used to evaluate the postoperative elbow function and complications. RESULTS: For MEP score, OMC was better than the locking plate; for DASH score, complication rate, and range of elbow motion, the two methods presented no significant difference. CONCLUSION: The study showed that OMC could be an effective alternative to treat olecranon fractures.

Biomechanical comparison of different stabilization constructs for unstable posterior wall fractures of acetabulum. A cadaveric study.

PURPOSE: Operative treatment of unstable posterior wall fractures of acetabulum has been widely recommended. This laboratory study was undertaken to evaluate static fixation strength of three common fixation constructs: interfragmentary screws alone, in combination with conventional reconstruction plate, or locking reconstruction plate. METHODS: Six formalin-preserved cadaveric pelvises were used for this investigation. A posterior wall fracture was created along an arc of 40-90 degree about the acetabular rim. Three groups of different fixation constructs (two interfragmentary screws alone; two interfragmentary screws and a conventional reconstruction plate; two interfragmentary screws and a locking reconstruction) were compared. Pelvises were axial loaded with six cycles of 1500 N. Dislocation of superior and inferior fracture site was analysed with a multidirectional ultrasonic measuring system. RESULTS: No statistically significant difference was found at each of the superior and inferior fracture sites between the three types of fixation. In each group, the vector dislocation at superior fracture site was significantly larger than inferior one. CONCLUSIONS: All those three described fixation constructs can provide sufficient stability for posterior acetabular fractures and allow early mobilization under experimental conditions. Higher posterior acetabular fracture line, transecting the weight-bearing surface, may indicate a substantial increase in instability, and need more stable pattern of fixation.

[Application of cannulated compression screws for the treatment of tibial tubercle avulsion fractures of Ogden type III in adolescents].

OBJECTIVE: To review the clinical outcome of the application of cannulated compression screws for the treatment of tibial tubercle avulsion fractures of Ogden type III in adolescents. METHODS: From January 2003 to October 2010,11 adolescent patients with tibial tubercle avulsion fractures were treated with open reduction and internal fixation. There were 9 boys and 2 girls with an average age of 15.2 years old (ranged, 12.4 to 17 years old). According to Ogden classification, there were 9 patients with type IIIa and 2 patients with type IIIb. Postoperative functional exercise and regular follow-up were done and outcomes were evaluated by the Mosier clinical assessment system. RESULTS: All the patients were followed up, and the duration ranged from 7 to 69 months, with a mean of 25.5 months. All fractures healed at the first stage. According to the Mosier clinical assessment system, the final outcome was evaluated as excellent in all. One patient had infrapatellar hypoesthesia, and one patient had prominency of tibial tubercle without any symptoms. CONCLUSION: The cannualted compression screws in the treatment of tibial tubercle avulsion fractures of Ogden type III in adolescents have an excellent outcome without deformity or functional loss.

[Posterior partial trochanteric osteotomy for the treatment of the roof involved acetabular fractures].

OBJECTIVE: To introduce a new trochanteric osteotomy,and evaluate the outcome of the procedure combined a posterior lateral approach in treating acetabular fractures which involving the roof. METHODS: Between March 2007 and Novmber 2010,30 patients with displaced acetabular fractures involving the dome need trochanteric osteotomy were retrospectively reviewed. There were 21 males and 9 females,ranging in age from 18 to 70 years with an average of 35.2 years at the time of injury. According to Letournel-Judet classification, there were 10 posterior wall fractures,7 posterior column fractures,5 transverse fractures, 2 T-shape fractures, 1 transverse associated with posterior wall fracture, 3 posterior column and wall fractures and 2 bicolumn fractures. The standards of Matta,the modified Merle d'Aubigne-Postel, Medical Research Council were respectively used to evaluate the reduction result, function of hip joint and the strength of hip abduction. RESULTS: All patients were followed up with an average time of 25 months (18 to 40) and all osteotomy sites obtained bone union with an average time of 8.4 weeks (6 to 12). No bone non-union, bone block displaceing, internal fixation looseing and breaking,infection of deep part were found. Seventeen patients got anatomic reduction, 12 got satisfied reduction, and 1 got unsatisfied result according to the criteria of Matta. At final follow-up, function of hip joint obtained excellent results in 11 cases, good in 15, fair in 3 and poor in 1. The strength of the abductors of 3 patients were grade 4 and 27 patients were grade 5. CONCLUSION: Posterior partial great trochanteric osteotomy can enhance the exposure and provide a more accurate reduction and degrade the difficulty of acetabular fracture fixation without increasing the risk of complications. The method provide a new way for the treatment of the roof involved acetabular fractures.

[Surgical treatment for posterior malleolus in complicated external rotation ankle fracture].

OBJECTIVE: To evaluate the indications, surgical techniques and clinical effects of the fixation of posterior malleolus in complicated external rotation ankle fractures and illuminate the importance of anatomical reduction and rigid internal fixation of posterior malleolar fracture. METHODS: From July 2007 to June 2009, 32 patients were treated with open reduction and internal fixation,involving 21 males and 11 females with an average age of 36 years old (ranged from 19 to 68 years old). According to Lauge-Hansen classification: 13 cases of pronation-external rotation type (IV), 7 and 12 cases of supination-external rotation type (III and IV). Postoperative functional exercise and regular follow-up were done and outcomes were assessed. RESULTS: All the patients were followed up,and the duration ranged from 7 to 20 months,with an average of 14.5 months. According to Ankle Hindfoot Clinical Rating System of the American Orthopaedic Foot & Ankle Society (AOFAS), 23 patients got an excellent result, 7 good, 2 fair, 0 poor. CONCLUSION: Anatomical reduction and rigid internal fixation of posterior malleolar fracture as well as early functional exercise have significance in restoring ankle joint function and reducing the incidence of traumatic arthritis.

[Case-control study on two methods for the treatment of calcaneal fractures].

OBJECTIVE: To investigate clinical results of percutaneous reduction and hollow screw internal fixation for the treatment of calcaneal fractures, and to compare therapeutic effects between close reduction hollow screw internal fixation and open reduction plate internal fixation. METHODS: From August 2007 to May 2010, 53 patients with calcaneal fractures were retrospectively analyzed. All the patients were divided into two groups, 25 patients in group A (PR group) treated with percutaneous reduction and hollow screw internal fixation, including 17 males and 8 females, with an average age of (39.4 +/- 9.9) years. While 28 patients in group B (OR group) treated with open reduction and plate internal fixation, including 18 males and 10 females, with an average age of (38.6 +/- 10.2) years. According to Sanders classification, there were 18 patients with type II fractures, 29 patients with type III and 6 type IV. In both groups, operative time, blood loss, postoperative complications and radiology were recorded. Functional recovery was evaluated by Maryland score. RESULTS: All the patients were followed up, and the duration ranged from nine months to thirty-five months (averaged 20.4 months). There were no significant differences in sex, age, fracture type, fracture classification, initial Böhler angle, or late complications between the two groups. But significant difference can be seen between operative time, blood loss, and skin complications (in group A no nonunion and skin complications occurred, but subtalar posttraumatic arthritis occurred in 1 case; in group B, 3 patients had complications of skin necrosis, 1 patient suffered from a delayed union due to large defect filled with artificial bone, and 1 patient got subtalar posttraumatic arthritis). No difference were found in the latest X-ray film. According to Maryland score, in group A, 8 got an excellent result and 12 good. In group B, 10 got an excellent and 14 good. There were no significant differences between the two groups in Margland score. CONCLUSION: The results of this study suggest that in comparison with open reduction, percutaneous reduction and hollow screw internal fixation minimizes complications and achieves good results. Further study of this technique is needed.