ObjectiveTo investigate the effectiveness of minimally invasive plate and medial supporting cannulated screw fixation via tarsal sinus approach in treatment of Sanders type Ⅱ and Ⅲ calcaneal fractures. Methods A clinical data of 46 patients with Sanders type Ⅱand Ⅲ calcaneal fractures met the selective criteria between March 2016 and March 2021 was retrospectively analyzed. The factures were fixed with minimally invasive plate and medial supporting cannulated screws via tarsal sinus approach in 20 cases (group A) and with minimally invasive plate in 26 cases (group B). There was no significant difference between groups in term of the gender, age, injury causes, fracture type and side, the time from injury to operation, and preoperative calcaneal length and width, Böhler angle, Gissane angle, and visual analogue scale (VAS) score (P>0.05). The operation time, intraoperative blood loss, hospital stay, and the interval between operation and full weight-bearing were recorded. The pain improvement of patients was evaluated by VAS scores before operation and at 48 hours after operation. The ankle joint function was evaluated by American Orthopaedic Foot and Ankle Society (AOFAS) score at 3 and 12 months after operation. Besides, the calcaneal length and width, Böhler angle, and Gissane angle were measured by X-ray films before and after operation. Furthermore, the difference (loss value) between 3, 12 months and 1 day after operation was calculated. Moreover, the fracture healing and healing time was observed. ResultsAll operations of two groups were successfully completed. The incisions healed by first intention, and no vascular/nerve injury or incision infection occurred. The operation time of group A was significantly longer than that of group B (P<0.05). There was no significant difference in the intraoperative blood loss, hospital stay, and the interval between operation and full weight-bearing (P>0.05). All patients were followed up 12-36 months (mean, 14.8 months). The VAS scores at 48 hours after operation were significantly lower than those before operation in the two groups (P<0.05); there was no significant difference in the difference of pre- and post-operative VAS score between groups (P>0.05). The AOFAS scores at 12 months after operation were significantly higher than those at 3 months after operation in the two groups (P<0.05); and there was no significant difference between groups at 3 and 12 months (P>0.05). X-ray films showed that the fractures of the two groups healed and there was no significant difference in healing time (P>0.05). There was no significant difference in calcaneal length and width and Gissane angle between groups at each time point (P>0.05), but there was significant difference in Böhler angle between groups at 12 months (P<0.05). The imaging indexes of the two groups significantly improved at each time point after operation when compared with those before operation (P<0.05). There was no significant difference between different time points after operation (P>0.05) in the imaging indexes of group A. There were significant differences in the calcaneal length, calcaneal width, and Gissane angle of group B between 12 months and 1 day, 3 months after operation (P<0.05), and there was no significant difference between 1 day and 3 months after operation (P>0.05). The differences in Böhler angle of group B between different time points after operation were significant (P<0.05). There was no significant difference between groups in the loss of all imaging indexes at 3 months after operation (P>0.05). The losses of calcaneal width, Böhler angle, and Gissane angle in group A at 12 months after operation were significantly smaller than those in group B (P<0.05), and there was no significant difference in the loss of calcaneus length between groups (P>0.05). ConclusionCompared with only minimally invasive plate fixation, the combination of minimally invasive plate and medial supporting cannulated screw fixation via tarsal sinus approach for Sanders type Ⅱ and Ⅲ calcaneal fractures has the advantages of less trauma, less incision complications, reliable fracture reduction and fixation, and good long-term stability.
ObjectiveTo compare the effectiveness of the femoral neck system (FNS) and inverted triangle cannulated screws (ITCS) for the treatment of Pauwels type Ⅲ femoral neck fractures.MethodsThe clinical data of 59 patients with Pauwels type Ⅲ femoral neck fractures treated between May 2019 and November 2020 were retrospectively analysed. The patients were divided into FNS group (28 cases) and ITCS group (31 cases) according to the different internal fixation. There was no significant difference in gender, age, affected side, body mass index, cause of injury, smoking history, alcohol abuse history, Pauwels angle, Garden classification, AO/Orthopaedic Trauma Association (AO/OTA) classification, and time from injury to operation between the two groups (P>0.05). The operation time, incision length, intraoperative blood loss, extra assisted reduction procedures (Kirschner wire prying reduction or open reduction), hospitalization stay, and early complications were recorded and compared between the two groups. Garden index and Haidukewych score were used to evaluate fracture reduction. Fracture healing time, lateral thigh irritation, time of partial or total weight-bearing postoperatively, shortening length and degree of femoral neck, change of caput-collum-diaphysis (CCD) angle (the difference of CCD angle between immediate after operation and last follow-up), incidence of osteonecrosis of femoral head and revision surgery were recorded and compared between the two groups. Hip joint function were evaluated by Harris score.ResultsThe operation time of FNS group was significantly shorter than ITCS group, and the incision length was significantly longer than ITCS group (P<0.05). There was no significant difference in intraoperative blood loss, assisted reduction, Garden index, Haidukewych score, and hospitalization stay between the two groups (P>0.05). All the incisions healed by first intention. There were 2 deep vein thrombosis in the FNS group and 1 pulmonary infection and 1 deep vein thrombosis in the ITCS group. No significant difference was found in the incidence of early postoperative complications (7.1% vs. 6.5%) between the two groups (P=1.000). Patients in both groups were followed up 3-14 months, and there was no significant difference in follow-up time between the two groups (t=–0.553, P=0.582). The fracture healing time, Harris score, and the partial weight-bearing time after operation of the FNS group were significantly better than those of the ITCS group (P<0.05). However, there was no significant difference in total weight-bearing time between the two groups (Z=–1.298, P=0.194). No lateral thigh irritation was found in the FNS group, while 10 patients in the ITCS group had lateral thigh irritation, and the incidence between the two groups (0 vs. 32.3%) was significant (P=0.001). At last follow-up, the shortening length and degree of femoral neck and the change of CCD angle in FNS group were significantly less than those in ITCS group (P<0.05). There was no patient with osteonecrosis of femoral head or reoperation in the FNS group, while 4 patients in the ITCS group underwent reoperation (including 2 cases of osteonecrosis of the femoral head). However, the incidences (0 vs. 6.5%; 0 vs. 12.9%) between the two groups were not significant (P=0.493; P=0.114).ConclusionUsing FNS to treat Pauwels type Ⅲ femoral neck fracture is simple as well as able to reduce the shortening of the femoral neck and the change of the CCD angle. Also, FNS is conducive to the recovery of hip joint function, which should be considered as a new choice for the treatment of young femoral neck fracture patients.
Objective To compare the efficacy and safety of dynamic hip screw (DHS) + anti-rotation screw and cannulated screw alone for femoral neck fracture in adults. Methods PubMed, Web of Science, Cochrane Library, China National Knowledge Infrastructure, SinoMed, Wanfang, and Chongqing VIP database were searched for the literature related to the comparison between DHS + anti-rotation screw and cannulated screw alone for femoral neck fracture in adults from the establishment of databases to 2022. RevMan 5.3 software was used for meta-analysis. Results Finally, 25 clinical studies were included, including 8 randomized controlled trials and 17 observational studies, 5 in English and 20 in Chinese. There were a total of 2099 patients, including 989 in the DHS + anti-rotation screw group and 1110 in the cannulated screw group. The meta-analysis results showed that the incidence of bone nonunion [odds ratio (OR)=0.29, 95% confidence interval (CI) (0.17, 0.48)], incidence of femoral head necrosis [OR=0.48, 95% CI (0.27, 0.88)], failure rate of internal fixation [OR=0.28, 95% CI (0.15, 0.51)] in the DHS + anti-rotation screw group were lower than those in the cannulated screw group (P<0.05). The surgical duration [mean difference (MD)=9.91, 95% CI (6.78, 13.05)], incision length [MD=1.25, 95% CI (0.15, 2.35)], and Harris score [MD=6.77, 95% CI (4.66, 8.88)] in the DHS + anti-rotation screw group were higher than those in the cannulated screw group (P<0.05). There was no statistically significant difference in intraoperative bleeding volume, Visual Analogue Scale score, hospital stay, and fracture healing time between the two groups (P>0.05). The incidence of bone nonunion in the DHS + anti-rotation screw group after Pauwels type Ⅲ fracture [OR=0.16, 95% CI (0.05, 0.50)] was lower than that in the cannulated screw group (P<0.05), and there was no statistically significant difference in the incidence of femoral head necrosis between the two groups (P>0.05). Conclusions For femoral neck fracture in adults, DHS + anti-rotation screw can reduce the incidence of bone nonunion, femoral head necrosis, and internal fixation failure compared with cannulated screw alone, and has a higher Harris score, but the surgical duration and incision are longer. Overall, DHS + anti-rotation screw are better at reducing the incidence of complications than cannulated screws alone.
Objective To evaluate the effectiveness of three-dimensional (3-D) printing assisting minimally invasive for intraarticular calcaneal fractures with percutaneous poking reduction and cannulate screw fixation. Methods A retrospective analysis was performed of the 19 patients (19 feet) with intraarticular calcaneal fracture who had been treated between March 2015 and May 2016. There were 13 males and 6 females with an average age of 38.2 years (range, 24-73 years). There were 3 open fractures and 16 closed fractures. By Sanders classification, 12 cases were type Ⅱ, 7 cases were type Ⅲ. By Essex-Lopresti classification, 13 cases were tongue type, 6 cases were joint-depression type. The time from injury to surgery was 1-10 days (mean, 4.7 days). A thin slice CT scan was taken of bilateral calcaneus in patients. By using the mirror imaging technique, the contralateral mirror image and the affected side calcaneus model were printed according to 1∶1 ratio. The displacement of fracture block was observed and contrasted, and the poking reduction was simulated. Calcaneal fracture was treated by percutaneous minimally invasive poking reduction and cannulate screw fixation. The Böhler angle and Gissane angle at immediate after operation and last follow-up was measured on X-ray films, and compared with preoperative measurement. The functional recovery was evaluated by American Orthopaedic Foot and Ankle Society (AOFAS) scores. Results The operation time was 25-70 minutes (mean, 45 minutes). The intraoperative blood loss was 10-40 mL (mean, 14.5 mL). All the incisions healed by first intention and had no relevant postoperative complications such as skin necrosis, nail tract infection, and osteomyelitis. All the patients were followed up 12-25 months (mean, 14.6 months). All patients obtained fracture healing, and the fracture healing time was 8-14 weeks (mean, 10.3 weeks). No screw withdrawal or breakage occurred during follow-up; only 1 patient with Sanders type Ⅱ fracture, whose calcaneus height was partially lost at 6 weeks after operation, the other patients had no reduction loss and fracture displacement, and no traumatic arthritis occurred. The Böhler angle and Gissane angle at immediate after operation and last follow-up were significantly improved when compared with preoperative ones (P<0.05), but there was no significant difference between at immediate after operation and last follow-up (P>0.05). The AOFAS score was 76-100 (mean, 88.2), and the results were excellent in 10 feet, good in 7, and fair in 2, the excellent and good rate was 89.5%. Conclusion 3-D printing assisting minimally invasive for intraarticular calcaneal fractures with percutaneous poking reduction and cannulate screw fixation can reduce the surgical trauma, improve the quality of reduction and fixation, and make the operation more safe, accurate, and individualized.
Objective To investigate the effectiveness of Holosight robotic navigation-assisted percutaneous cannulated screw fixation for femoral neck fractures. Methods A retrospective analysis was conducted on 65 patients with femoral neck fractures treated with cannulated screw fixation between January 2022 and February 2024. Among them, 31 patients underwent robotic navigation-assisted screw placement (navigation group), while 34 underwent conventional freehand percutaneous screw fixation (freehand group). Baseline characteristics, including age, gender, fracture side, injury mechanism, Garden classification, Pauwels classification, and time from injury to operation, showed no significant differences between the two groups (P>0.05). The operation time, intraoperative blood loss, fluoroscopy frequency, fracture healing time, and complications were recorded and compared, and hip function was evaluated by Harris score at last follow-up. Postoperative anteroposterior and lateral hip X-ray films were taken to assess screw distribution accuracy, including deviation from the femoral neck axis, inter-screw parallelism, and distance from screws to the femoral neck cortex. Results No significant difference was observed in operation time between the two groups (P>0.05). However, the navigation group demonstrated superior outcomes in intraoperative blood loss, fluoroscopy frequency, deviation from the femoral neck axis, inter-screw parallelism, and distance from screws to the femoral neck cortex (P<0.05). No incision infections or deep vein thrombosis occurred. All patients were followed up 12-18 months (mean, 16 months). In the freehand group, 1 case suffered from cannulated screw dislodgement and nonunion secondary to osteonecrosis of femoral head at 1 year after operation, 1 case suffered from screw penetration secondary to osteonecrosis of femoral head at 5 months after operation; and 1 case suffered from nonunion secondary to osteonecrosis of femoral head at 6 months after operation in the navigation group. All the 3 patients underwent internal fixators removal and total hip arthroplasty. There was no significant difference in the incidence of complications between the two groups (P>0.05). The fracture healing time and hip Harris score at last follow-up in the navigation group were significantly better than those in the freehand group (P<0.05). ConclusionCompared to freehand percutaneous screw fixation, Holosight robotic navigation-assisted cannulated screw fixation for femoral neck fractures achieves higher precision, reduced intraoperative radiation exposure, smaller incisions, and superior postoperative hip function recovery.
ObjectiveTo investigate and analyze the effectiveness of internal fixation with the two different cannulated screw implanting methods of rhomboid and inverted triangle in the treatment of femoral neck fracture in young adults.MethodsThe clinical data of 38 young adults with femoral neck fracture who met the selection criteria between January 2018 and August 2019 were retrospectively analyzed. According to the different methods of cannulated screw implanting, the patients were divided into two groups, 19 cases in each group. The trial group was treated with closed reduction and cannulated screw rhombic distribution internal fixation, while the control group was treated with closed reduction and cannulated screw inverted triangular distribution internal fixation. There was no significant differences in patients’ gender, age, cause of injury, Garden classification of fracture, and time from injury to operation between the two groups (P>0.05). The fracture healing time, the incidence of nonunion, femoral neck shortening, and femoral head necrosis were recorded and compared between the two groups; the effectiveness was evaluated by Harris score and visual analogue scale (VAS) score at last follow-up.ResultsThe incisions of the two groups healed by first intention. All patients were followed up 12-24 months with an average of 15.5 months. There were 1 case of fracture nonunion and 2 cases of shortening of femoral neck in the trial group; while there were 2 cases of fracture nonunion, 1 case of necrosis of femoral head, and 6 cases of femoral neck shortening in the control group; the difference in the incidence of complications (15.8% vs. 47.4%) between the two groups was significant (χ2=4.385, P=0.036). The remaining 18 cases in the trial group and 17 cases in the control group all achieved osteonal union, and the healing time was (14.8±1.6) weeks and (15.9±1.3) weeks, respectively, showing no significant difference between the two groups (t=1.265, P=0.214). At last follow-up, Harris score and VAS score of the trial group were 88.9±4.3 and 1.1±0.7, respectively, while those of the control group were 86.9±5.9 and 1.3±0.9, respectively, showing no significant difference (t=0.603, P=0.550; t=1.152, P=0.257). Hip function was evaluated in accordance with Harris score, the results were excellent in 12 cases, good in 6 cases, and fair in 1 case in the trial group, the excellent and good rate was 94.74%; the results were excellent in 10 cases, good in 7 cases, and fair in 2 cases in the control group, the excellent and good rate was 89.47%; there was no significant difference in the excellent and good rate between the two groups (χ2=0.368, P=0.544).ConclusionThe short-term effectiveness of the two kinds of cannulated screw implanting methods is clear, rhomboid fixation of 4 screws has strong stability with stress distribution, which can effectively reduce the incidence of femoral neck shortening, fracture nonunion, femoral head necrosis, and other complications.
Objective To design a new type of three-dimensional honeycomb guide for percutaneous cannulated screw placement in femoral neck fracture and evaluate its effectiveness. Methods The clinical data of 40 patients with femoral neck fracture who met the selection criteria between June 2019 and December 2020 were retrospectively analyzed. According to different intraoperative positioning methods, they were divided into control group (20 cases, free hand positioning screws) and study group (20 cases, new guide assisted positioning screws). There was no significant difference in gender, age, side, cause of injury, Garden classification, and time from injury to operation between the two groups (P>0.05). The operation time, fluoroscopy times, guide needle puncture times, and fracture healing time of the two groups were recorded. The hip function was evaluated by Harris score at last follow-up. At immediate after operation, the following imaging indexes were used to evaluate the accuracy of screw implantation distribution: screw spacing, screw coverage area, distance from screw to cervical cortex, parallelism between screws, and screw to cervical axial deviation. Results All operations were successfully completed, and the guide needle did not penetrate the femoral neck cortex. There was no significant difference in operation time and fluoroscopy times between the two groups (P>0.05); the guide needle puncture times in the study group was significantly less than that in the control group (t=8.209, P=0.000). Imaging detection at immediate after operation showed that the screw spacing and screw coverage area in the study group were significantly greater than those in the control group (P<0.05); the distance from screw to cervical cortex, parallelism between screws, and screw to cervical axial deviation were significantly smaller than those in the control group (P<0.05). All patients were followed up 7-25 months, with an average of 19.3 months. There was no significant difference in follow-up time between the two groups (t=−0.349, P=0.729). There were 2 cases of fracture nonunion in the control group and 1 case in the study group, and the other fractures completely healed. One case of osteonecrosis of the femoral head occurred in the control group. During the follow-up, there was no complication such as vascular and nerve injury, venous thrombosis, screw penetration, withdrawal, breakage, and refracture, etc. There was no significant difference in fracture healing time and Harris score at last follow-up between the two groups (P>0.05). ConclusionThe new three-dimensional honeycomb guide has the advantages of simple structure and convenient use. It can reduce the puncture times of the guide needle and effectively improve the accuracy distribution of cannulated screw implantation.
ObjectiveTo evaluate the feasibility and effectiveness of percutaneous cannulated screw fixation for the treatment of Day type Ⅱ pelvic crescent fracture.MethodsThe clinical data of 14 patients with Day type Ⅱ pelvic crescent fractures underwent closed reduction and percutaneous cannulated screw fixation between January 2009 and July 2016 were retrospectively analysed. There were 9 males and 5 females, aged 17-65 years (mean, 38 years). The causes of injury included traffic accident in 8 cases, falling from height in 3 cases, bruise injury in 3 cases; all were closed fractures. According to Tile classification, there were 8 cases of type B, 6 cases of type C. There were 13 cases combined with fracture of the anterior pelvic ring, including 8 cases of superior and inferior ramus of pubis fracture, 1 case of superior ramus of pubis fracture with symphysis separation, and 4 cases of symphysis separation. The interval of injury and admission was 1- 72 hours (mean, 16 hours), and the interval of injury and operation was 3-8 days (mean, 5 days). After operation, the reduction of fracture was evaluated by the Matta evaluation criteria, the clinical function was assessed by Majeed function assessment.ResultsThe operation time was 35-95 minutes (mean, 55 minutes), cumulative C-arm fluoroscopy time was 3-8 minutes (mean, 5 minutes), no iatrogenic vascular injury and pelvic organ damage occurred. Postoperative X-ray films at 2 days indicated that 2 cases of vertical shift and 2 cases of mild rotation were not completely corrected. Postoperative CT examination at 3 days indicated that 2 pubic joint screws broke through the obturator bone cortex. None of the pubic ramus screws entered into the acetabulum, but a screw of superior pubic branch broke through the posterior cortical of superior pubic branch, a screw of posterior ilium column broke through the medial bone cortex of the ilium, and no clinical symptom was observed. One patient suffered from wound infection in the pubic symphysis, then healed after 2 weeks of wound drainage, the other wounds healed by first intention. According to Matta criterion for fracture reduction, the results were excellent in 9 cases, good in 4 cases, and fair in 1 case with an excellent and good rate of 92.9%. All patients were followed up 8-24 months (mean, 14 months). All fractures healed at 4 months and restored to the normal walking at 6 months after operation, 3 patients suffered from slight pain in the sacroiliac joints and slight claudication when they were tired or walked for a long time and unnecessary for special treatment. One patient felt pain in the back of the iliac spine when he was lying down. During the follow-up, no screw loosening or other internal fixation failure occurred. At last follow-up, according to Majeed functional evaluation criteria, the results were excellent in 7 cases, good in 5 cases, and fair in 2 cases with an excellent and good rate of 85.7%.ConclusionThe percutaneous cannulated screw fixation is a safe treatment for Day type Ⅱ pelvic crescent fracture, which has a reliable fixation and good effectiveness.
Objective To compare the effectiveness of full thread compression cannulated screw and partial thread cannulated screw in the treatment of femoral neck fracture. Methods A retrospective analysis was made on 152 patients with femoral neck fractures, who met the selection criteria, between April 2013 and February 2021. The fractures were fixed with the full thread compression cannulated screws in 74 cases (trial group) and the partial thread cannulated screws in 78 cases (control group). There was no significant difference in general data such as age, gender, body mass index, cause of injury, time from injury to operation, and the side, Garden typing, Pauwels typing of fracture between the two groups (P>0.05). The operation time, intraoperative blood loss, hospital stay, follow-up time, and Harris score were recorded in both groups. X-ray films were performed to evaluate the quality of fracture reduction and bone healing, the changes of neck-shaft angle, the changes of femoral neck, as well as the occurrence of internal fixation failure, screw back-out, and osteonecrosis of the femoral head. Results There was no significant difference in operation time and hospital stay between the two groups (P>0.05). However, the intraoperative blood loss in the trial group was significantly lower than that in the control group (P<0.05). Patients in both groups were followed up, with the follow-up time of (24.11±4.04) months in the trial group and (24.10±4.42) months in the control group, and the difference was not significant (P>0.05). Postoperative X-ray films showed that there was no significant difference in fracture reduction grading between the two groups (P>0.05). Six cases in the trial group developed bone nonunion and 7 cases in the control group, the fractures of the other patients healed, and the healing time was significantly shorter in the trial group than in the control group (P<0.05). There was no significant difference in the incidence of bone nonunion between the two groups (P>0.05). During follow-up, 2 cases in the trial group and 5 cases in the control group had osteonecrosis of the femoral head, the difference was not significant (P>0.05), and the patients with osteonecrosis of the femoral head were treated with secondary operation. The screw back-out occurred in 3 cases of the trial group and in 9 cases of the control group, showing no significant difference (P>0.05). But the screw back-out distance was significantly shorter in the trial group than in the control group (P<0.05). The incidence of internal fixation failure in the trial group (4 cases) was significantly lower than that in the control group (14 cases) (P<0.05). The incidence of femoral neck shortening and the change of neck-shaft angle at 1 year after operation were significantly lower in the trial group than in the control group (P<0.05). The Harris score at last follow-up was significantly higher in the trial group than in the control group (P<0.05). Conclusion Compared with the partial threaded cannulated screws, the full threaded cannulated compression screws can effectively maintain fracture reduction, avoid femoral neck shortening, and internal fixation failure. It is a better choice for femoral neck fracture.
Objective To evaluate the internal fixation effect, degradation, and biocompatibility of polylactic-co-glycolic acid/hydroxyapatite (PLGA/HA) absorbable cannulated screws in treatment of lateral femoral condyle fracture of canine so as to provide the theory basis for their further improvement and clinical application. Methods Sixteen adult male Beagles (weighing, 9-12 kg) were selected to prepare the models of bilateral lateral femoral condyle fracture; left fracture was fixed with PLGA/HA absorbable cannulated screws as experimental group and right fracture with metal screws as control group. At 2, 4, 8, and 12 weeks after operation, general observation was done and X-ray films were taken for observing fracture healing; bone mineral density was measured; the histological examination was performed; and the degradation property of absorbable cannulated screws was detected. Results All animals survived to the end of the experiment. General observations showed that no fracture displacement occurred and fracture healed at 12 weeks in 2 groups; no breakage, displacement, or loosening of screws was observed in experimental group. X-ray films results showed that the absorbable cannulated screws could not be found out by X-ray in experimental group, but metal screws could be found out in control group; fracture healed with time in 2 groups. The bone mineral density reached the peak at 8 weeks in 2 groups, and no significant difference was found between 2 groups and among different time points in the same group (P gt; 0.05). Histological examination showed that 2 groups had similar fracture healing process at different time points; no obvious inflammatory reaction was found around absorbable cannulated screws in experimental group. The degradation results of absorbable cannulated screws showed that the intrinsic viscosity and molecular weight distribution obviously decreased at 2 weeks; the number average molecular weight and the weight average molecular weight markedly decreased at 4 weeks; and the maximum shear force did not decrease obviously at 8 weeks, and then decreased significantly. Significant differences were found in all indexes among different time points in the same group (P lt; 0.05). Conclusion PLGA/HA absorbable cannulated screws and metal screws show similar fracture healing process for fixing lateral femoral condyle fracture of canine, and the absorbable canulated screws have good biocompatibility. The maximum shear force of PLGA/HA absorbable cannulated screw has no obvious decrease during 8 weeks after operation, so it can ensure full healing of fracture.