Bone Nails Research Articles

A Review of the Development of Titanium-Based and Magnesium-Based Metallic Glasses in the Field of Biomedical Materials.

This article reviews the research and development focus of metallic glasses in the field of biomedical applications. Metallic glasses exhibit a short-range ordered and long-range disordered glassy structure at the microscopic level, devoid of structural defects such as dislocations and grain boundaries. Therefore, they possess advantages such as high strength, toughness, and corrosion resistance, combining characteristics of both metals and glasses. This novel alloy system has found applications in the field of biomedical materials due to its excellent comprehensive performance. This review discusses the applications of Ti-based bulk metallic glasses in load-bearing implants such as bone plates and screws for long-term implantation. On the other hand, Mg-based metallic glasses, owing to their degradability, are primarily used in degradable bone nails, plates, and vascular stents. However, metallic glasses as biomaterials still face certain challenges. The Young's modulus value of Ti-based metallic glasses is higher than that of human bones, leading to stress-shielding effects. Meanwhile, Mg-based metallic glasses degrade too quickly, resulting in the premature loss of mechanical properties and the formation of numerous bubbles, which hinder tissue healing. To address these issues, we propose the following development directions: (1) Introducing porous structures into titanium-based metallic glasses is an important research direction for reducing Young's modulus; (2) To enhance the bioactivity of implant material surfaces, the surface modification of titanium-based metallic glasses is essential. (3) Developing antibacterial coatings and incorporating antibacterial metal elements into the alloys is essential to maintain the long-term effective antibacterial properties of metallic biomaterials. (4) Corrosion resistance must be further improved through the preparation of composite materials, while ensuring biocompatibility and safety, to achieve controllable degradation rates and degradation modes.

Numerical study on the effect of temperature rise of humeral bone nails in magnetic resonance imaging based on the finite-element method.

Humeral fracture is a common long bone fracture in orthopedic clinical diagnosis and treatment. To investigate the local temperature increase owing to changes in the specific absorption ratio (SAR) of the human body caused by humeral bone nails during magnetic resonance imaging (MRI). A refined geometric model of the upper body was constructed via data segmentation and post-processing using the digital human image dataset. Finally, the geometric model was imported into COMSOL, a 3-T magnetic resonance coil was built, and the operating frequency (128 MHz) was set to analyze the SAR of the bone-nail pair and temperature changes. The analysis of the changes after bone-nail implantation under different tissue conditions revealed that the SAR and temperature after implantation and fixation were three times higher than those before, and the areas with abrupt changes in SAR and temperature were primarily concentrated in the bone-nail area. In MRI, metal implants can cause local elevation of the SAR near the implant in the human body, resulting in a temperature increase around the implant. Consequently, long-term scanning can damage the human body.

Results of Allografts and Synthetic Grafts in Humeral Simple Bone Cysts.

Simple bone cysts (SBCs) are the most common benign bone lesions in childhood. There are many different methods in the treatment of SBCs. There is no consensus on which method to use in the treatment. In this study, we compared the results of allogeneic bone graft or synthetic bone graft in addition to fl exible intramedullary nail (FIN) for SBC located in the humerus. This retrospective study comparing the data of 19 (group 1: 8 curettage, allograft and FIN; group 2: 11 curettage, synthetic graft and FIN) patients with a mean age of 11.4 (6 to 26; seven female, twelve male) who were surgically treated in our hospital for humeral SBC between April 2014 and January 2020. Patient data included age, sex, anatomical side, stage of the cyst, pathological fracture, previous treatments and complications. The mean follow-up period was 33.7 months (12 to 61). The average last follow-up Musculoskeletal Tumor Society functional scores for groups 1 and 2 were 27.8 (20 to 30) and 28.6 (21 to 30) (P > 0.05). Complete or signifi cant partial radiographic healing rates were achieved in group 1 (75%) compared with group 2 (81.9%). The reoperation rates for groups 1 and 2 were 62.5% (5/8; three for nails removed, two for recurrence) and 36.3% (4/11; two for nails removed, two for recurrence). One patient in group 2 had a 15° varus deformity due to recurrence. No other complications were observed. The combination of curettage-grafonage FIN is a common treatment method in recent years, as it provides early cyst healing and limb mobilization in SBCs located in the upper extremity. For defects after curettage of the bone cysts, allogeneic or synthetic grafts (granule b-tricalcium phospate) which have similar results in terms of healing can be used as an alternative to each other. allografts, bone cysts, bone nails, synthetic grafts, humerus.

Effect of reverse hammering on fracture union in transverse fracture of long bone nailing

Reverse hammering is the method applied during nailing of transverse long bone fracture to decrease the gap between fracture ends to ensure healing. This study aims to asses the effectiveness of reverse hammering on fracture union in transverse fracture of long bone nailing as well as possible complications of this method. Seventy six patients with transverse fracture of long bone (femur, tibia, & humerus) treated with close reduction and internal fixation with interlocking nailing were enrolled in a prospective study conducted at the department of orthopaedics, BMC Sagar from Dec. 2012 to March 2021. Union grading was done to asses union as per Hammer criteria. Mean time to achieve bony union was 4.5 months. In our study seven out of seventy six patient at the end of three month were having radiological grade three or less union which at the end of nine month only two patient out of seventy six patient were having nonunion. Our results have been encouraging. The operation is technically demanding but provides an excellent method to achieve union in intramedullary nailing of long bones. This method to reduce fracture gap should be considered for patients requiring a faster return to function after the injury.

Effects of calcium glycerophosphate concentration on micro-arc oxidation coating of Mg alloy

Due to its good biocompatibility and compatible hardness with human bones, magnesium (Mg) alloy is considered as a promising material for bone nails and implants. However, Mg and its alloys are characteristics of active chemical properties and high corrosion rate, which is detrimental to the recovery of patients implanted with Mg alloy bone scaffold. In the present work, to retard the corrosion of the Mg alloy, calcium glycerophosphate (C3H7CaO6P•H2O) was added in the electrolyte to form the micro-arc oxidation (MAO) coatings. Various experimental techniques such as XRD, SEM and EDS have been used to characterize the surface morphology and phase composition of MAO coatings. MAO coatings of different CaP content were studied to explore the synergetic effect between the biocompatibility and corrosive properties by means of electrochemical measurements, hemolysis and pyrogen test. The results showed that higher CaP content can improve the biocompatibility and corrosion resistance while decelerating the hemolysis rate.

Systematic study of (TiZr)xNby(TaMo)z medium entropy alloys for biomedical implants

In this study, four (TiZr)xNby(TaMo)z medium entropy alloys (MEAs) have been investigated as biomedical implants systematically, including their phase structure, microstructure, mechanical properties, corrosion resistance, in vitro biocompatibility and in vivo implantation. With the addition of Ta and Mo, the yield strength of the alloys increased from 678 ± 17 MPa to 821 ± 14 MPa, and their elastic modulus rose from 52 ± 2 GPa to 59 ± 2 GPa. The strength-elastic modulus performance of the alloys was superior to that of most β-titanium alloys. The pseudo-binary solid solution strengthening theory exhibited that the strength enhancement of the alloys was attributed to the high modulus mismatch between Mo, Ta and other elements. And the bonding force of transition group elements based on Coulomb's law and d-electron alloy theory could explained the change in elastic modulus precisely. The alloys with corrosion current densities ranging from 3.277 × 10−7 A/cm2 to 5.105 × 10−7 A/cm2 performed better corrosion resistance than pure Ti, and their oxide films were composed of oxides of each constituent element. In addition, the alloys exhibited comparable in vitro biocompatibility to pure Ti and Zr. Finally, the alloys with lowest elastic modulus were implanted in the mid-femur of Sprague Dawley (SD) rats for 12 weeks, no toxic tissue response was observed and the new bone formed around them. In summary (TiZr)xNby(TaMo)z alloys with low elastic modulus and good strength might be used as materials for bone nails, intramedullary nails and bone plates in the future.

Retracted: A Clinical Study on the Treatment of Multiple Radial Fractures with Embedded Wearable Device Holder and Absorption Bone Nail Combined with Decoction.

[This retracts the article DOI: 10.1155/2021/6617823.].

EVALUATION OF FUNCTIONAL AND RADIOLOGICAL OUTCOMES OF ADULT DIAPHYSEAL FRACTURES OF BOTH BONE FOREARM OPERATED WITH PLATING OR NAILING

Background: Fractures of both radius and ulna are one of the most common fractures in adults in upper extremity .It is essential to regain length, apposition, axial alignment and normal rotational alignment while treating diaphyseal fractures of the radius and the ulna to gain good range of pronation and supination. Mal-union and nonunion occur more frequently because of the difculty in reducing and maintaining the reduction of two parallel bones in the presence of the pronating and supinating muscles that have angulating and rotational inuences). There lies a controversy with respect to choice of treatment as per chances of infection, duration of healing and the surgeon preferences. The present study is thus undertaken to compare functional outcome and radiological union using two different surgical modalities i.e. Dynamic Compression Plating and Intramedullary nailing. All adult patients(>12years) with Materials And Methods: diaphyseal fractures of both bones of forearm presenting to A&E department, requiring operative intervention were selected and were included in an interventional and comparative prospective cohort study.A total of 48 subjects fullling eligibility criteria were randomly divided into four groups A, B, C and D (12 each) using random number table. Most cases with Results: excellent to good functional outcome was seen in both bones plating group (100%) followed by hybrid techniques. Incidence of mal-union was seen in 2 cases each of both bone nailing and ulnar plating and radius nailing and in 1 case of radius plating and ulnar nailing. Among the four different xation methods for treating both bone diaphyseal forea Conclusion: rm fractures in adults, the method with both bone i.e. ulna and radius plate xation showed good stability in biomechanics, the lowest complication rate and best functional recovery outcomes

Image-guided, surgical robot-assisted percutaneous puncture of the foramen ovale and foramina stylomastoideum: a cadaveric study.

Image-guided, surgical robot-assisted percutaneous puncture of the foramen ovale and foramina stylomastoideum: a cadaveric study.

A Clinical Study on the Treatment of Multiple Radial Fractures with Embedded Wearable Device Holder and Absorption Bone Nail Combined with Decoction.

Multiple radial fractures have brought great pain to the patients, and the treatment takes a long time and the effect is slow, which seriously affects people's production and life. Traditional conservative treatment methods are mostly used for radius fractures. However, with the development of science and technology of the times, the level of medical treatment is also constantly improving. For radius fractures, the embedded wearable device fixation frame absorption bone nail treatment method has attracted attention. In order to study whether the embedded wearable device fixation frame can treat radius fractures, this article conducted a related survey of radius fracture patients in a hospital in a certain city, reviewed related literature, conducted interviews with professionals and so forth, and collected relevant information. A case template was constructed, and a clinical research model was created using a comprehensive quantitative and qualitative analysis method. The results of the study found that using the research embedded wearable device fixation frame to treat radius fractures with absorption bone nails can achieve good results, and its healing efficiency is about 20% faster than conservative treatment. With decoction, its treatment efficiency can be improved; and the prognostic treatment of the decoction can reduce the complications of the patient's treatment by about 13%. This shows that the embedded wearable device holder absorption bone nail combined with decoction can play an important role in the treatment of multiple radius fractures.

Treatment and outcomes of basicervical femoral neck fractures: A systematic review.

This study aims to systematically review the literature comparing surgical treatments options and respective failure rates for basicervical hip fractures. A comprehensive search of databases, including MEDLINE, Embase, Web of Science, and Cochrane Central for studies published in English on or before June 21, 2019 was performed. Selected search terms included "basicervical," "basi cervical," "AO/OTA type 31-B," "femoral neck fracture" AND "bone nails," "bone screws," "fracture fixation," "internal fixation," "arthroplasty," "cephalomedullary," "sliding hip screw," "ORIF," and "treatment outcome." We included studies that assessed outcomes of basicervical fracture fixation using open reduction internal fixation or arthroplasty. Two authors extracted the following data from each paper: study design, country, cohort year, definition of basicervical, intervention type, sample size, patient demographics, follow-up length, percent of fractures that required revision, and the percent of implants that failed. Sixteen articles encompassing 910 patients were included. The main outcome was the percent of implants that required revision. The total revision rates were 8% (8 studies, 157 patients, range 0%-55%) for cephalomedullary nails, 7% (10 studies, 584 patients, range 0%-18%) for sliding hip screws, 23% (3 studies, 40 patients, range 16%-50%) for cannulated screws, 0% (1 study, 6 patients) for total hip arthroplasty, and 8% (2 studies, 13 patients, range 0%-11%) for hemiarthroplasty. Management of basicervical fractures with SHS and CMN produces similar failure and re-operation rates. Limited evidence is available on the use of cannulated screws and arthroplasty, but available studies suggest that cannulated screws have an unacceptable revision rate (23%) while arthroplasty may be acceptable. Future studies examining the comparative efficacy of various fixation methods would benefit from strict definition of fracture type as well as consistent reporting of functional outcomes, re-operation rates, and mortality.

Systematic review of complications with externally controlled motorized intramedullary bone lengthening nails (FITBONE and PRECICE) in 983 segments

Background and purpose — In recent years motorized intramedullary lengthening nails have become increasingly popular. Complications are heterogeneously reported in small case series and therefore we made a systematic review of complications occurring in lower limb lengthening with externally controlled motorized intramedullary bone lengthening nails. Methods — We performed a systematic search in PubMed, EMBASE, and the Cochrane Library with medical subject headings: Bone Nails, Bone Lengthening, and PRECICE and FITBONE nails. Complications were graded on severity and origin. Results — The search identified 952 articles; 116 were full text screened, and 41 were included in the final analysis. 983 segments were lengthened in 782 patients (age 8–74 years). The distribution of nails was: 214 FITBONE, 747 PRECICE, 22 either FITBONE or PRECICE. Indications for lengthening were: 208 congenital shortening, 305 acquired limb shortening, 111 short stature, 158 with unidentified etiology. We identified 332 complications (34% of segments): Type I (minimal intervention) in 11% of segments; Type II (substantial change in treatment plan) in 15% of segments; Type IIIA (failure to achieve goal) in 5% of segments; and Type IIIB (new pathology or permanent sequelae) in 3% of segments. Device and bone complications were the most frequent. Interpretation — The overall risk of complications was 1 complication for every 3 segments lengthened. In 1 of every 4 segments, complications had a major impact leading to substantial change in treatment, failure to achieve lengthening goal, introduction of a new pathology, or permanent sequelae. However, as no standardized reporting method for complications exists, the true complication rates might be different.

Multidisciplinary team for treatment of hip fracture in the elderly

Objective To explore multidisciplinary team (MDT) for the treatment of hip fracture in the elderly. Methods A retrospective analysis was done of the 196 elderly patients who had been admitted to Department of Joint Surgery, Beijing Shijitan Hospital from September 2017 to December 2018 for hip fractures. They were divided into 2 groups depending on whether MDT had been applied or not. In the MDT group of 102 patients, there were 43 males and 59 females with an age of 81.9±8.4 years, and 63 femoral neck fractures and 39 intertrochanteric fractures. In the traditional treatment group of 94 patients, there were 37 males and 57 females with an age of 81.3±8.6 years, and 55 femoral neck fractures and 39 intertrochanteric fractures. The 2 groups were compared in terms of complications and mortality during hospitalization, interval from admission to surgery, total hospital stay, and Harris hip scores at 6 months after surgery. Results There were no statistically significant differences in general data before surgery between the 2 groups, indicating comparability (P>0.05). Eighty-four patients (89.4%) in the traditional treatment group and 98 patients (96.1%) in the MDT group underwent surgery, showing no significant difference between the groups (χ2=3.327, P=0.068). In the patients undergoing surgery in the MDT group, the incidences of postoperative delirium [12.2% (12/98)], pulmonary infection [11.2% (11/98)], cardiogenic disease [13.3%(13/98)], electrolyte disturbance[12.2%(12/98)] and deep venous thrombosis of lower extremity [6.1% (6/98)] were significantly lower, the interval from admission to surgery (1.9 d±0.9 d) and total hospital stay (10.2 d±0.9 d) significantly shorter, and Harris hip scores (81.3±6.2) at 6 months after surgery significantly higher than those in the patients undergoing surgery in the traditional treatment group [31.0%(26/84), 22.6% (19/84), 25.0% (21/84), 28.6% (24/84), 16.7%(14/84); 3.1 d±1.6 d and 14.1 d±6.2 d; 75.4±7.8; respectively] (all P<0.05). Conclusion In the treatment of hip fracture in the elderly, multidisciplinary team is effective in reducing complications during hospitalization, shortening the interval from admission to surgery and total hospital stay, and promoting functional recovery of the hip. Key words: Hip fractures; Fracture fixation, intramedullary; Bone nails; Arthroplasty, replacement, hip; Multidisciplinary team

Gamma 3 nails combined with hollow compression screw fixation for intertrochanteric fracture of risky external wall type

Objective To evaluate Gamma 3 nails combined with hollow compression screw fixation in the treatment of intertrochanteric fracture of risky external wall type. Methods From November 2015 to December 2017, 60 patients with intertrochanteric fracture of risky external wall type were treated at Department of Orthopaedic Surgery, Wuhan Fourth Hospital. Of them, 27 ones, 15 males and 12 females with an age of 57.5 years±16.2 years (group A), were fixated with Gamma 3 nails and hollow compression screws, including 14 cases of AO type of 31-A2.2 and 13 cases of AO type of 31-A2.3. The other 33 patients, 18 males and 15 females with an age of 59.3 years±15.1 years (group B), were fixated with Gamma 3 nails alone, including 17 cases of AO type of 31-A2.2 and 16 cases of AO type of 31-A2.3. The 2 groups were compared in terms of operation time, hospitalization time, intraoperative blood loss, weight-bearing time, fracture healing time, complications and Harris hip scores at the final follow-up. Results The 2 groups were comparable due to insignificant differences between them in preoperative general data (P>0.05). The 60 patients obtained an average follow-up of 22.6 months (from 12 to 36 months). There were no statistically significant differences in operation time, intraoperative blood loss or hospital stay between the 2 groups (P>0.05). Group A had a significantly lower incidence of external wall redisplacement [7.4% (2/27)], significantly shorter weight-bearing time(5.4 weeks±1.0 weeks) and fracture healing time(18.3 weeks±3.9 weeks), and significantly higher Harris hip scores at the final follow-up (89.3±7.1) than group B did [24.2% (8/33), 7.4 weeks±1.3 weeks, 21.7 weeks±5.6 weeks and 79.5±8.3, respectively] (all P< 0.05). Follow-ups revealed no complications like femoral head cutting, implant breakage, deep vein thrombosis of lower limb, fat embolism, hip varus deformity or nail breakage in either group. Conclusion In the treatment of intertrochanteric fracture of risky external wall type, compared with Gamma 3 nails alone, Gamma 3 nails combined with hollow compression screw fixation can avoid external wall displacement or fixation failure after external medullary fixation or intramedullary fixation alone but does not increase operation time or intraoperative blood loss, leading to better functional recovery. Key words: Hip fractures; Fracture fixation, intramedullary; Bone nails

Natural reduction at prone position in treatment of femoral subtrochanteric fractures with intramedullary nailing

Objective To evaluate natural reduction at prone position in the treatment of femoral subtrochanteric fractures with intramedullary nailing. Methods The clinical data of 7 patients with subtrochanteric fracture were retrospectively analyzed who had been treated at Orthopaedic Department, Beijing Tsinghua Changgung Hospital from August 2016 to April 2018. They were 4 males and 3 females, aged from 31 to 87 years (average, 55.6 years). Their fractures happened on the left side in 3 patients and on the right side in 4. By the Seinsheimer classification, there were 3 cases of type Ⅱ, 2 cases of type Ⅲ and 2 cases of type Ⅴ. The time from injury to surgery ranged from 9 to 44 hours, averaging 26 hours. All patients were treated by intramedullary nailing after natural reduction at prone position. Their preoperative preparation time, time required for reduction, total operation time, fluoroscopic frequency for guide pin insertion, fluoroscopic frequency for reduction, reduction quality, complications and curative effect were recorded. Results Closed reduction and intramedullary nail fixation were completed uneventfully in all the 7 cases. Their preoperative preparation time averaged 29.4 min (from 21 to 42 min), reduction time 6.3 min (from 3 to 10 min), and total operation time 157 min (from 82 to 275 min). Their fluoroscopic frequency averaged 37 times (from 14 to 96 times) for guide pin insertion and 23 times (from 10 to 49 times) for reduction, totaling 244 times (from 121 to 360 times). According to the modified Baumgaetner criteria, the fracture reduction was evaluated as excellent in 6 cases and as fair in one. The 7 patients were followed up for 12 to 34 months (mean, 20.1 months). A drill broke at the interlocking nail hole during operation in one patient, deep venous thrombosis occurred at a lower extremity in another during hospitalization, and fracture nonunion was observed after operation in another, but no complications related to the prone position were observed. The curative effect evaluated by Harris hip score at the last follow-up was excellent in 4 cases, as good in 2 cases and as fair in one. Conclusion In the treatment of femoral subtrochanteric fractures with intramedullary nailing, the prone position benefits natural reduction and maintenance of reduction and allows convenient fluoroscopy and nail placement during operation, especially for obese patients. Key words: Hip fractures; Fracture fixation, intramedullary; Bone nails; Reduction; Prone position

Cannulated screw fixation versus high-strength suture fixation in arthroscopy of tibial intercondylar fracture

Objective To compare the cannulated screw fixation versus high-strength suture fixation in arthroscopy of tibial intercondylar fracture. Methods A retrospective analysis was performed of the 31 patients with tibial intercondylar fracture who had been treated from February 2015 to February 2018 at Department of Orthopaedics, Beijing Renhe Hospital. They were 18 males and 13 females with an average age of 34.3 years (range, from 21 to 51 years). Arthroscopic cannulated screw fixation was conducted in 13 patients (screwing group), 5 of whom were McKeever type Ⅱ and 8 of whom McKeever type Ⅲ. Arthroscopic high-intensity suture fixation was used in 18 patients (suture group), 6 of whom were McKeever type Ⅱ and 12 of whom McKeever type Ⅲ. The 2 groups were compared postoperatively in terms of operation time, hospitalization time, fracture healing time, Lysholm knee scores and rate of secondary operation. Results The 2 groups were comparable because there were no significant differences in preoperative general data between them (P>0.05). All the patients were followed up for 12 to 44 months (mean, 24.8 months). For the screwing and suture groups, respectively, operation time was 91.6 min±7.6 min and 91.9 min±7.4 min, hospitalization time 11.5 d±2.9 d and 11.4 d±2.3 d and fracture healing time 3.3 mon±0.5 mon and 3.3 mon±0.6 mon, showing no significant differences between the 2 groups (P>0.05). By the Lysholm scores at 12 months after operation, the screwing group scored from 65 to100 points with an excellent and good rate of 92.3% (12/13), and the suture group from 60 to 100 points with an excellent and good rate of 94.4% (17/18), showing no significant difference between the 2 groups (P>0.05). Ten patients (76.9%) in the screwing group had secondary arthroscopy to remove the implants but none in the suture group did. Conclusions Both cannulated screw fixation and high-strength suture fixation can achieve satisfactory clinical results in the arthroscopy of tibial intercondylar fractures, but the latter may lead to a lower rate of secondary operation. Key words: Arthroscopy; Fracture fixation, internal; Bone nails; High strength suture; Tibial eminence fracture

The fifth metacarpal neck fracture treated by closed reduction and intramedullary fixation with antegrade Kirschner wire plus rod rotation technique

Objective To assess the clinical effects of closed reduction and intramedullary fixation with antegrade Kirschner wire plus rod rotation technique in the treatment of the fifth metacarpal neck fracture. Methods In this retrospective study, 26 patients with the fifth metacarpal neck fracture were treated by closed reduction and intramedullary fixation with antegrade Kirschner wire plus rod rotation technique at Department of Orthopaedics, Central Hospital of Karamay from August 2015 to October 2017. They were 23 males and 3 females, aged from 12 to 53 years with an average age of 25.2 years. In the intramedullary nailing, a Kirschner wire pre-bent by 10° to 15° was inserted from the base of the fifth metacarpal into the medullary canal before closed reduction. After satisfactory reduction was achieved, the Kirschner wire was inserted across the fracture site into the metacarpal head for further reduction and fixation using rod rotation technique. After operation, a plaster was applied to protect the fixation for 2 weeks. Functional exercise was started after removal of the plaster. The Kirschner wire was not removed under local anaesthesia at the outpatient department until about 10 to 16 weeks postoperation when X-ray showed fracture healing. Records of their operation time, head/shaft angle of the fifth affected metacarpal, active range of motion of the metacarpophalangeal joints and Total Active Movement (TAM) of hand function at the last follow-up were collected. Results Their operation time averaged 21 minutes (from 12 to 35 minutes). Anatomical reduction was achieved in 23 cases but not in 3 ones whose metacarpal head/shaft angle and alignment were obviously improved. Follow-ups for 6 to 29 months (average, 15.8 months) showed all the patients obtained solid fracture healing with no infection or delayed fracture healing. The head/shaft angle was improved significantly from preoperative 61.2°±11.2° to postoperative 14.7°±3.5° (P 0.05). The active range of motion of the metacarpophalangeal joint was 89.3°±4.2° after fixation removal, not significantly different from that of the healthy side (90.7°±1.5°) (P>0.05). According to TAM scores at the last follow-up, 22 cases were rated as excellent, 3 as good and one as fair. Conclusion In the treatment of the fifth metacarpal neck fracture, closed reduction and intramedullary fixation with antegrade Kirschner wire plus rod rotation technique is effective, because it is simple and limitedly invasive, and leads to limited complications, low costs and secondary reduction. Key words: Metacarpal bone; Fracture fixation, intramedullary; Bone nail; Fifth metacarpal neck fracture; Rod rotation

A biomechanical comparison of single- versus double-threaded cannulated screws for femoral neck fractures of Pauwels type III

Objective To compare the biomechanical performance between the single- versus double-threaded cannulated screws in the treatment of femoral neck fractures of Pauwels type Ⅲ. Methods Models of femoral neck fracture of Pauwels type Ⅲ (70°) were made of the Sawbone synthetic composite femurs. All specimens were divided into 2 groups (n=12). Group A was fixated with single-threaded cannulated screws and group B with double-threaded cannulated screws, both in an inverted triangle configuration. The screws ranged from 90 to 95 mm in length and from 7.3 to 7.5 mm in diameter. All the specimens were subjected to axial stiffness and failure load tests with 7° valgus (simulating normal two-legged weight-bearing stance) and 25° valgus (simulating normal one-legged weight-bearing stance) and torsion test as well. The 2 groups were compared in the torques at axial stiffness angles of 1°, 2°, 3°, 5° and 7°. Results Group B had significantly greater axial stiffness at 7° valgus and 25° valgus (89±26 N/mm and 128±37 N/mm) and failure load (1,154±368 N) than group A did (36±12 N/mm and 47±16 N/mm; 688±94 N) (P< 0.05). The torques increased with the increase in rotation angle in both groups. However, the torques in group B (3.26±0.96, 4.16±1.23, 4.64±1.13, 5.59±1.26 and 6.53±1.47 N·m) were all significantly larger than in group A (1.44±0.19, 2.03±0.41, 2.33±0.62, 2.74±0.87 and 3.05±1.07 N·m) (P<0.05). Conclusion Double-threaded cannulated screws may provide better biomechanical stability than single-threaded ones, due to their substantial improvement in anti-compression and anti-rotation performance. Key words: Femoral neck fractures; Fracture fixation, internal; Bone nails; Biomechanics; Pauwels Ⅲ

Arthroscopic riveting with line versus lateral retinacular release plus medial patellofemoral ligament re-construction for habitual patellar dislocation

Objective To compare the clinical efficacy between arthroscopic riveting with line and lateral retinacular release plus medial patellofemoral ligament reconstruction in the treatment of habitual patellar dislocation. Methods A retrospective study was conducted of the 40 children with habitual patellar dislocation who had been treated at Department of Pediatric Orthopaedics, Foshan Hospital of Traditional Chinese Medicine from January 2016 to December 2016. They were divided evenly into an observation group and a control group according to the treatment methods (n=20). In the observation group which was treated by lateral retinacular release plus medial patellofemoral ligament reconstruction, there were 14 boys and 6 girls, with an age of 14.2±1.2 years and an average number of dislocations of 5.3±1.1 times. In the control group which was treated by arthroscopic riveting with line, there were 13 boys and 7 girls, with an age of 13.8±1.3 years and an average number of dislocations of 5.5±1.2 times. The 2 groups were compared in terms of visual analogue score (VAS), Q-angle, knee motion, Lysholm score and Kujala score of the knee at the last follow-ups. Results The 2 groups were comparable due to insignificant differences in preoperative general data between them (P>0.05). The observation and control groups were followed up for 13.3±1.2 months and 12.9±1.2 months, respectively, showing no significant difference between them(P>0.05). At the last follow-ups, the observation group had a significantly lower VAS score (2.2±0.8 pints), a significantly smaller Q-angle (14.5°±1.2°), significantly larger knee motion (30.3°±3.8°), and significantly higher Lysholm (91.6±5.3 points) and Kujala scores (93.2±2.8 points) than the control group (4.3±1.1 points, 17.8°±1.6°, 23.4°±3.4°, 81.4±4.4 points and 82.0±5.4 points, respectively) (all P<0.05). Conclusion In the treatment of habitual patellar dislocation, lateral retinacular release plus medial patellofemoral ligament reconstruction can lead to improvements in knee function and clinical symptoms and better clinical outcomes than arthroscopic riveting with line. Key words: Patellar dislocation; Arthroscopy; Bone nails; Lateral retinaculum; Medial patellofemoral ligament

Clinical comparative study of metaphyseal locking intramedullary nail and locking plate in the treatment of humeral surgical neck fracture

Objective To investigate the difference of clinical efficacy between metaphyseal locking intramedullary nail and locking plate in the treatment of humeral surgical neck fracture. Methods 64 patients with Neer II humeral surgical neck fracture who were treated in our hospital from January 2010 to December 2015 were selected. According to the operation plan, the patients were divided into epiphyseal locking intramedullary nail fixation group (observation group, n=42) and locking plate fixation group (control group, n=22). The differences of clinical data (sex, age, time from injury to operation, number of injured cases, follow-up time), clinical indicators (neck-trunk angle, last neck-trunk angle, number of complications, amount of operative bleeding, amount of operative blood transfusion, operation time, fracture healing time): Neer shoulder function score and Constant shoulder score were compared between the two groups. Results There was no significant difference in gender, age, time from injury to operation, number of cases of injury and follow-up time between the two groups, and the subjects were comparable (P>0.05). There was no significant difference in the neck-trunk angle, the last neck-trunk angle and the number of complications between the two groups (P>0.05); the observation group had longer operation time, less operation bleeding volume and blood transfusion volume, shorter fracture healing time (P 0.05). The Constant score, external rotation, abduction and flexion in the observation group were significantly higher than those in the control group (P<0.05). Conclusions The use of metaphyseal locking intramedullary nail in the treatment of humeral surgical neck fracture has a definite clinical effect and a low incidence of complications, which is worthy of clinical application. Key words: Humeral fractures; Shoulder fractures; Fracture fixation, intramedullary; Bone nails; Bone plates