Biomechanical investigation of S2 alar-iliac screw and S1 pedicle screw fixation in the treatment of Denis type II sacral fractures.

Although S2 alar-iliac screw technique has been widely used in spinal surgery, its applicability to pelvic fractures is largely unknown. This study aimed to evaluate the biomechanical stability of S2 alar-iliac screw and S1 pedicle screw fixation in the treatment of Denis II sacral fractures. Twenty-eight artificial pelvic fracture models were treated with unilateral lumbopelvic fixation, sacroiliac screw fixation, S2 alar-iliac screw and S1 pedicle screw fixation, and S2 alar-iliac screw and contralateral S1 pedicle screw fixation (Groups 1-4, respectively; N = 7 per group). Each model was cyclically tested under increasing axial compression. Optical motion-tracking was used to assess relative displacement and gap angle, and the number of failure cycles. Relative displacement was significantly smaller in Group 3 than in Groups 1 (p = 0.004) and 4 (p < 0.001) but not significantly different between Groups 3 and 2 (p = 0.290). The gap angle in Group 3 was significantly smaller than that in Group 1 (p = 0.009) on the sagittal plane but significantly larger than that in Group 4 (p = 0.006) on the horizontal plane. A number of failure cycles was significantly higher in Group 3 than in Groups 1 (p = 0.002) and 4 (p = 0.004) but not significantly different between Groups 3 and 2 (p = 0.910). From a biomechanical perspective, S2 alar-iliac screw and S1 pedicle screw fixation can provide good stability in the treatment of Denis II sacral fractures.

Prospective randomized multicenter noninferiority clinical trial evaluating the use of TFN-advancedTM proximal femoral nailing system (TFNA) for the treatment of proximal femur fracture in a Chinese population.

PURPOSE: To evaluate whether the 24-weeks postoperative fracture union rate for the investigational TFNA intramedullary nail was non-inferior compared to the control product PFNA-II. METHODS: The study was a prospective, randomized, single-blind, noninferiority dual-arm study drawing from 9 trauma centers across China, between November 2018 and September 2020, with follow-up measurements at 24 weeks after internal fixation. The full analysis data set (FAS [Intent-to-Treat]) was analyzed and is summarized here. The primary outcome was fracture union rate, a composite score combining clinical and radiographic assessment. Secondary endpoints comprised (a) clinical outcomes including (1) SF-12, (2) Harris Hip, and (3) EQ-5D Scores, (b) radiographic incidence of complications such as loosening or cut-out requiring revision, (c) revision rates, (d) reoperation rates, and (e) adverse events, including 24-weeks revision and reoperation rates. RESULTS: Both TFNA and PFNA-II group fracture healing rates were 100% at 24 weeks; TFNA was therefore shown to be non-inferior to PFNA-II. With baseline data matched in all parameters except age in both the TFNA and PFNA-II groups, comparisons of union rates, SF-12, Harris Hip, and EQ-5D Scores yielded p values > 0.05 indicating no significant difference between the two groups, further supporting the noninferiority of TFNA. In both groups, revision and re-operation rates were 0, and the incidences of serious adverse events were 19.4% and 17.4%, respectively. CONCLUSION: In terms of fracture union rate at 24 weeks, the DePuy Synthes Trochanteric Fixation Nail Advanced (TFNA) was not inferior to the marketed Proximal Femoral Nail Antirotation (PFNA-II) device produced by the same manufacturer. Secondary and safety outcomes showed no significant differences between the two groups. REGISTRATION: Registration was completed at ClinicalTrials.gov NCT03635320.

S2-alar-iliac screw and S1 pedicle screw fixation for the treatment of non-osteoporotic sacral fractures: a finite element study.

BACKGROUND: Five different sacral fracture fixation methods were compared using finite element (FE) analysis to study their biomechanical characteristics. METHODS: Denis type I sacral fractures were created by FE modeling. Five different fixation methods for the posterior pelvic ring were simulated: sacroiliac screw (SIS), lumbopelvic fixation (LPF), transiliac internal fixator (TIFI), S2-alar-iliac (S2AI) screw and S1 pedicle screw fixation (S2AI-S1) and S2AI screw and contralateral S1 pedicle screw fixation (S2AI-CS1). Four different loading methods were implemented in sequence to simulate the force in standing, flexion, right bending and left twisting, respectively. Vertical stiffness, relative displacement and change in relative displacement were recorded and analyzed. RESULTS: As predicted by the FE model, the vertical stiffness of the five groups in descending order was S2AI-S1, SIS, S2AI-CS1, LPF and TIFI. In terms of relative displacement, groups S2AI-S1 and S2AI-CS1 displayed a lower mean relative displacement, although group S2AI-CS1 exhibited greater displacement in the upper sacrum than group S2AI-S1. Group SIS displayed a moderate mean relative displacement, although the displacement of the upper sacrum was smaller than the corresponding displacement in group S2AI-CS1, while groups LPF and TIFI displayed larger mean relative displacements. Finally, in terms of change in relative displacement, groups TIFI and LPF displayed the greatest fluctuations in their motion, while groups SIS, S2AI-S1 and S2AI-CS1 displayed smaller fluctuations. CONCLUSION: Compared with SIS, unilateral LPF and TIFI, group S2AI-S1 displayed the greatest biomechanical stability of the Denis type I sacral fracture FE models. When the S1 pedicle screw insertion point on the affected side is damaged, S2AI-CS1 can be used as an appropriate alternative to S2AI-S1.

Chitosan-strontium chondroitin sulfate scaffolds for reconstruction of bone defects in aged rats.

Bone defects caused by trauma have become increasingly common in aged populations. Clinically, because of the relatively decreased bone healing capacity compared with the youth adults, bone defect repair in the elderly remains challenging. The development of effective biomaterials targeted at bone defects in the elderly is a key component of bone-tissue engineering strategies. However, little attention has been paid to bone regeneration in the elderly. Here, we developed a new scaffold chitosan-Strontium chondroitin sulfate (CH-SrCS) and evaluated its effect on improving bone regeneration. We find that the CH-SrCS scaffold displayed positive effects on downregulation of inflammation and osteoclastogenesis related mRNA expressions while demonstrating a significant increase in the expression level of BMP2. Finally, we show that the bone defects healing effects as assessed using an aged rats' bone defects model. Ultimately, this work also provides insights into the design of effective biomaterials targeted at bone defects in the elderly.

Can barb thread design improve the pullout strength of bone screws?

AIMS: To draw a comparison of the pullout strengths of buttress thread, barb thread, and reverse buttress thread bone screws. METHODS: Buttress thread, barb thread, and reverse buttress thread bone screws were inserted into synthetic cancellous bone blocks. Five screw-block constructs per group were tested to failure in an axial pullout test. The pullout strengths were calculated and compared. A finite element analysis (FEA) was performed to explore the underlying failure mechanisms. FEA models of the three different screw-bone constructs were developed. A pullout force of 250 N was applied to the screw head with a fixed bone model. The compressive and tensile strain contours of the midsagittal plane of the three bone models were plotted and compared. RESULTS: The barb thread demonstrated the lowest pullout strength (mean 176.16 N (SD 3.10)) among the three thread types. It formed a considerably larger region with high tensile strains and a slightly smaller region with high compressive strains within the surrounding bone structure. The reverse buttress thread demonstrated the highest pullout strength (mean 254.69 N (SD 4.15)) among the three types of thread. It formed a considerably larger region with high compressive strains and a slightly smaller region with high tensile strains within the surrounding bone structure. CONCLUSION: Bone screws with a reverse buttress thread design will significantly increase the pullout strength. Cite this article: Bone Joint Res 2021;10(2):105-112.

The Effect of Knee Flexion on Length Changes and Stress Distribution of Ligaments: A Displacement Controlled Finite Element Analysis.

The use of dynamic finite element analysis to investigate the biomechanical behavior of the knee joint is mainly based on movement of the joint. Challenges are associated with simulation of knee joint flexion-extension activity. This study investigated changes in the length and stress state of ligaments during lunge with a displacement controlled finite element analysis of the knee joint based on in vivo fluoroscopic kinematic data. The geometric center axis (GCA) was used to represent knee kinematics to quantify femoral motion relative to the tibia. Because the GCA was considered as a functional flexion axis, 2 degrees of freedom could be reduced. Published data on the in vivo fluoroscopic kinematic features of the GCA were used to establish the equations for degrees of freedom. Data for 4 degrees of freedom were obtained simultaneously at every 5° of knee flexion. Displacement and rotation were applied to the femur and tibia to produce relative displacement, and the elongation and stress state of the knee ligaments were computed. The predictions confirmed that lunge affected the biomechanical behavior of ligaments. Displacement controlled finite element analysis of knee flexion can be simulated on the basis of fluoroscopic kinematic data to achieve physiologic movement. [Orthopedics. 2021;44(1):e61-e67.].

Impact of postoperative haemoglobin on length of stay post fractured hip repair in patients with standardised perioperative management.

INTRODUCTION:: Perioperative blood transfusion is not without risk and effort should be made to limit patients' exposure to allogeneic blood. However, there is conflicting data regarding the impact of anaemia on postoperative recovery in patients with repaired hip fractures. It is hypothesised that for a given baseline functional status and fracture type, lower postoperative haemoglobin will increase rehabilitation time and prolong total length of hospital stay. METHODS:: This is a retrospective study on data collected prospectively on patients entered into the Clinical Pathway aged >65 years admitted to Queen Mary Hospital (QMH) with a fractured neck of femur during 2011-2013. Potential predictor variables were analysed with linear regression with respect to total length of stay and those that reached a significance level of 0.05 were included in further analysis. RESULTS:: 1092 patients were admitted to QMH with a suspected fractured neck of femur; data from 747 patients were analysed. The fracture sites were neck of femur (50%), intertrochanteric (48%) and subtrochanteric fracture (2%). Approximately 30% of patients received blood transfusions. Of these only the development of postoperative medical complications statistically prolonged hospital stay. No relationship was seen with haemoglobin levels cut-off above and below 10 g/dl with the result remaining non-significant down to a cut-off of above and below 8 g/dl. DISCUSSION:: This study revealed that post-surgical haemoglobin level of between 8 g/dl and 10 g/dL did not have an impact on the total length of hospital stay. The development of postoperative medical complications was the only factor that prolonged the total length of stay.

Bone resorption triggered by high radial stress: The mechanism of screw loosening in plate fixation of long bone fractures.

Screw loosening is a common complication in plate fixation. However, the underlying mechanism is unclear. This study investigated screw loosening mechanisms by finite element analysis (FEA) simulation and clinical X-ray feature analysis. Two FEA models incorporated bone heterogeneity and orthotropy, representing fracture fixation using dynamic compression plate (DCP) and locking compression plate (LCP), were developed. These models were used to examine the volume of bone exceeding a certain stress value around each screw under physiologically-relevant loading conditions. These damaged bone was then separated and compared by the axial stress and radial stress of each screw. In addition, features of patients' X-ray images showing screw loosening were analyzed to validate the loosening features simulated by the models. The FEA study showed that more damaged bone was found at the central two screws which gradually decreased toward the two end screws in all groups. More bone was damaged by the radial stress of each screw than by the axial stress. The radiological analysis of screw loosening showed that bone loss occurred at the screw closest to the fracture line first then subsequent bone loss at the screws further away from the fracture line occurred. This study found that the two screws nearest to the fracture line are more vulnerable to loosening. The radial stress of the screw plays a larger role in screw loosening than the axial stress. Bone resorption triggered by the high radial stress of screws is indicated as the mechanism of screw loosening in the diaphyseal plate fixation. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1498-1507, 2019.

Effectiveness of a Day Rehabilitation Program in Improving Functional Outcome and Reducing Mortality and Readmission of Elderly Patients With Fragility Hip Fractures.

INTRODUCTION: The incidence of hip fracture is projected to increase in the next 25 years as the world population ages. Hip fracture is often associated with subsequent readmission and mortality. Nevertheless, elderly patients often may not achieve the same level of functional ability as prior to their injury. Several studies have shown that close collaboration between orthopedic surgeons and geriatricians can improve such outcomes and Geriatric Day Hospital (GDH) is one of the examples of collaboration to improve such outcomes. The aim of this descriptive retrospective study is to review the effectiveness of the day rehabilitation program provided by a GDH on functional outcomes, mortality, and readmission rate, among a sample of elderly patients with hip fracture. METHODS: The medical records of patients from January 1, 2009, to December 31, 2012, were collected and evaluated. Demographic data of the patients and Charlson Comorbidity Index were collected. The Barthel Index, Elderly Mobility Scale, and Mini-Mental State Examination were measured on admission and at discharge of the patients to evaluate both physical and cognitive functions. RESULTS: The results showed that the majority of patients benefited from rehabilitation in the GDH. The 12-month mortality rate of patients taking full-course rehabilitation in the GDH was improved. The age of patient was the most important factor influencing the rehabilitation outcomes. Gender was the only risk factor for 12-month mortality and 6-month readmission. DISCUSSION: Since patients were selected to attend GDH, there was a bias during the selection of patients. Furthermore, it was difficult to compare patients attended GDH with patients who did not because outcomes of the latter were difficult to be recorded. CONCLUSIONS: Our study shows that postoperative geriatric hip fracture patients definitely can benefit from rehabilitation service offered by GDH in terms of functional and cognitive outcomes.

Development and initial validation of a novel smoothed-particle hydrodynamics-based simulation model of trabecular bone penetration by metallic implants.

A novel computational model of implant migration in trabecular bone was developed using smoothed-particle hydrodynamics (SPH), and an initial validation was performed via correlation with experimental data. Six fresh-frozen human cadaveric specimens measuring 10 × 10 × 20 mm were extracted from the proximal femurs of female donors (mean age of 82 years, range 75-90, BV/TV ratios between 17.88% and 30.49%). These specimens were then penetrated under axial loading to a depth of 10 mm with 5 mm diameter cylindrical indenters bearing either flat or sharp/conical tip designs similar to blunt and self-tapping cancellous screws, assigned in a random manner. SPH models were constructed based on microCT scans (17.33 µm) of the cadaveric specimens. Two initial specimens were used for calibration of material model parameters. The remaining four specimens were then simulated in silico using identical material model parameters. Peak forces varied between 92.0 and 365.0 N in the experiments, and 115.5-352.2 N in the SPH simulations. The concordance correlation coefficient between experimental and simulated pairs was 0.888, with a 95%CI of 0.8832-0.8926, a Pearson ρ (precision) value of 0.9396, and a bias correction factor Cb (accuracy) value of 0.945. Patterns of bone compaction were qualitatively similar; both experimental and simulated flat-tipped indenters produced dense regions of compacted material adjacent to the advancing face of the indenter, while sharp-tipped indenters deposited compacted material along their peripheries. Simulations based on SPH can produce accurate predictions of trabecular bone penetration that are useful for characterizing implant performance under high-strain loading conditions. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1114-1123, 2018.

Augmentation of a Locking Plate System Using Bioactive Bone Cement-Experiment in a Proximal Humeral Fracture Model.

INTRODUCTION: The purpose of this study was to test whether local filling of a novel strontium-containing hydroxyapatite (Sr-HA) bone cement can augment the fixation of a locking plate system in a cadaveric proximal humeral facture model. MATERIALS AND METHODS: Twelve pairs of formalin-treated cadaveric humeri were used. One side in each pair was for cemented group, while the other side was for the control group. The bone mineral density (BMD) of the samples was tested. A 3-part facture model was created and then reduced and fixed by a locking plate system. In the cemented group, the most proximal 4 screw holes were filled with 0.5 mL bone cement. In the control group, the screw holes were not filled by cement. Locking screws were inserted in a standard manner before the cement hardened. X-ray was taken before all the specimens being subjected to mechanical study, in which 6 pairs were used for axial loading (varus bending) test, while other 6 pairs were used for axial rotational test. RESULTS: There is no difference in BMD between the cemented side and the control side. The X-ray shows that the implant is in position. Cement filling was noted in the most proximal 4 screws in the cemented group. Better mechanical outcome was seen in the cemented groups, in terms of less maximal displacement per cycle and higher failure point and stiffness in varus bending test. However, no difference was found between the cemented group and the control group in the axial rotation test. DISCUSSION: In similarity with the previous studies, our results showed better mechanical results in the cemented group. However, due to the limitations (e.g. sample size, fracture model, testing protocol, etc), we still cannot directly extrapolate current mechanical results to clinical practice at the present moment. Furthermore, it is still unknown whether better primary outcome may lead to better long-term results, even though the local release of strontium may enhance the local bone formation. CONCLUSION: The local filling of Sr-HA bone cement augments the fixation of the locking plate system in current proximal humeral fracture model.

Functionalized Polymeric Membrane with Enhanced Mechanical and Biological Properties to Control the Degradation of Magnesium Alloy.

To achieve enhanced biological response and controlled degradation of magnesium alloy, a modified biodegradable polymer coating called polycaprolactone (PCL) is fabricated by a thermal approach in which the heat treatment neither alters the chemical composition of the PCL membrane nor the rate of magnesium ion release, pH value, or weight loss, compared with the untreated sample. The changes in the crystallinity, hydrophilicity, and oxygen content of heat-treated PCL coating not only improve the mechanical adhesion strength between the coating and magnesium substrate but also enhance the biological properties. Moreover, the thermally modified sample can lead to higher spreading and elongation of osteoblasts, due to the enhanced hydrophilicity and CO to CO functional group ratio. In the analyses of microcomputed tomography from one to four weeks postoperation, the total volume of new bone formation on the heat-treated sample is 10%-35% and 70%-90% higher than that of the untreated and uncoated controls, respectively. Surprisingly, the indentation modulus of the newly formed bone adjacent to the heat-treated sample is ≈20% higher than that of both controls. These promising results reveal the clinical potential of the modified PCL coating on magnesium alloy in orthopedic applications.

Development of novel implants with self-antibacterial performance through in-situ growth of 1D ZnO nanowire.

To prevent the attachment of bacteria to implant surfaces, the 1D zinc oxide nanowire-coating has been successfully developed on material surfaces by using a custom-made hydrothermal approach. The chemical nature, surface topography and wettability of spike-like 1D ZnO nanowire-coating are comprehensively investigated. The anti-adhesive and antimicrobial properties of 1D nanowire-coating are tested against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli by using in vitro live/dead staining and scanning electron microscopy. We find that the adhesion of bacteria can be reduced via the special spike-like topography and that the release of Zn(2+) ions can help suppress the growth of attached bacteria. Furthermore, the antimicrobial effect is also evaluated under in vivo conditions by using a rat model infected with bioluminescent S. aureus. The amount of live bacteria in the rat implanted with a nanowire-coated sample is less than that of the control at various time points. Hence, it is believed that the nanowire-coated material is promising for application in orthopaedic implantation after the long-term animal studies have been completed.

In vivo stimulation of bone formation by aluminum and oxygen plasma surface-modified magnesium implants.

A newly developed magnesium implant is used to stimulate bone formation in vivo. The magnesium implant after undergoing dual aluminum and oxygen plasma implantation is able to suppress rapid corrosion, leaching of magnesium ions, as well as hydrogen gas release from the biodegradable alloy in simulated body fluid (SBF). No released aluminum is detected from the SBF extract and enhanced corrosion resistance properties are confirmed by electrochemical tests. In vitro studies reveal enhanced growth of GFP mouse osteoblasts on the aluminum oxide coated sample, but not on the untreated sample. In addition to that a small amount (50 ppm) of magnesium ions can enhance osteogenic differentiation as reported previously, our present data show a low concentration of hydrogen can give rise to the same effect. To compare the bone volume change between the plasma-treated magnesium implant and untreated control, micro-computed tomography is performed and the plasma-treated implant is found to induce significant new bone formation adjacent to the implant from day 1 until the end of the animal study. On the contrary, bone loss is observed during the first week post-operation from the untreated magnesium sample. Owing to the protection offered by the Al2O3 layer, the plasma-treated implant degrades more slowly and the small amount of released magnesium ions stimulate new bone formation locally as revealed by histological analyses. Scanning electron microscopy discloses that the Al2O3 layer at the bone-implant interface is still present two months after implantation. In addition, no inflammation or tissue necrosis is observed from both treated and untreated implants. These promising results suggest that the plasma-treated magnesium implant can stimulate bone formation in vivo in a minimal invasive way and without causing post-operative complications.

[Application of minimally invasive locking compression plate in treatment of distal tibia fractures].

OBJECTIVE: To evaluate the application of minimally invasive plate osteosynthesis (MIPO) technique in treatment of distal tibia fractures with locking compression plate (LCP). METHODS: From August 2002 to August 2007, 62 subjects were recruited (36 males and 26 females) at mean age of 44 years old (range, 21-87 years old). According to AO classification, there were 8 cases of type A1, 15 cases of type A2, 9 cases of type A3, 7 cases of type B3, 11 cases of type C1, and 12 cases of type C2. Of them, 52 patients had closed fractures and 10 had open fractures. Ten open fractures included 6 Grade I fracture and 4 Grade II fracture. The time from injury to operation was 8 hours to 6 days. The X-ray films were taken after 3 months of operation. RESULTS: Near anatomical reduction was achieved in 56 fractures and acceptable reduction in 6 fractures. Mean operation time was 43 minutes (range, 37-120 minutes). Primary healing of surgical wounds was observed in all cases. Subjects were followed up for 23 months on average (ranged, 18-45 months). All fractures healed with a mean healing time of 19.5 weeks (range, 16-32 weeks). According to Teens and Wiss ankle scoring system, 30 patients got excellent results, 25 good, and 7 fair; and the excellent and good rate was 88.7% at 12-month follow-up. There were 7 cases of delayed soft tissue infection which needed implant removal. There was one complication of compartment syndrome which required fasciotomy. There was one case with loss of reduction (valgus tilting of tibial plafond) that required bone grafting. CONCLUSION: The results of MIPO LCP in treatment of distal tibia fractures were satisfactory. This technique was safe with no incidence of serious complications.

[Application of minimally invasive locking compression plate in treatment of proximal humeral fractures].

OBJECTIVE: To evaluate the clinical and radiological outcomes of minimally invasive plate osteosynthesis (MIPO) with locking compression plate (LCP) in the treatment of proximal humeral shaft fracture. METHODS: From July 2004 to April 2008, 26 patients with displaced fractures of the proximal humeral shaft were recruited, including 8 males and 18 females. Age of patients averaged 66 years old (range, 34-82 years old). According to AO classification, there were 4 cases of type A1, 2 cases of type A2, 8 cases of type B1, 4 cases of type B2, 2 cases of type B3, 4 cases of type C1 and 2 cases of type C2. The time from injury to surgery averaged 2 days (range, 1-5 days). There were 8 osteoporotic fractures. RESULTS: All surgical wound healed primarily, and there was no wound infection. Three patients had postoperative radial nerve neurapraxia, which recovered at 4, 6, 8 months respectively. All patients were followed up for 6-24 months with an average of 14.1 months. Radiological examination revealed bony union within 6 months in 25 cases. There was 1 delayed union which remained asymptomatic and eventually healed at 8 months with acceptable Constant-Murley score. There were 3 cases of shoulder impingement syndrome diagnosed at 3 months post-operatively. After implant removal, they all achieved an acceptable Constant-Murley score. According to Constant-Murley scoring system, there were 11 excellent, 10 good and 5 acceptable results. The excellent or good rate was 80.8%. CONCLUSION: MIPO technique using LCP is an effective method to treat proximal humeral shaft fractures, which facilitates functional recovery of the shoulder joint. During the surgery, it is important to achieve a good fracture reduction and to avoid complications.

[Clinical effects of locking plate system in treating distal radial fractures].

OBJECTIVE: To determine the clinical results of locking plate system in the treatment of distal radial fractures. METHODS: From May 2004 to November 2006, 75 patients were treated with 2.4 mm locking plate system. There were 41 males and 34 females, with a mean age of 51 years old (range, 13-82 years old). The locations were left side in 34 cases and right side in 41 cases. The cause of injury was a low energy fall in 49 cases, falling from height in 14 cases, traffic accident in 6 cases and sports injuries in 6 cases. All patients were diagnosed as having closed fracture. According to Müller-AO classification, there were 14 cases(18.7%) of type A, 5 cases(6.7%) of type B, and 56 cases(74.6%) of type C. The time from injury to operation was 5 hours to 27 days (mean 6 days). RESULTS: A total of 75 patients were followed up at 3 months, 71 patients at 6 months, 68 patients at 1 year and 51 patients at 2 years. Healing by first intention of incision was achieved in 73 cases, and infection occurred in 2 cases. Fracture reduction failed at 1 month, 3 months and 6 months in 1 case, respectively; 1 case received plaster fixation and 2 cases received re-fixation and autograft of ilium; and fracture healed in 3 cases at last follow-up. Two patients complained of skin numbness at site of superficial branch of radial nerve after 1 day, 1 patient had wound pain after operation, and 1 patient had infection of tendon at 3 days and 5 days in 1 case respectively. At last follow-up, the ranges of motion of wrist joint were (80 +/- 9) degrees for pronation, (86 +/- 7) degrees for supination, (57 +/- 10) degrees for dorsal flexion, (51 +/- 13) degrees for palmar flexion, (18 +/- 7) degrees for radial inclination, and (28 +/- 7) degrees for ulnar deviation. According to modified Green scoring, the results were excellent in 66 cases, good in 6 cases and poor in 3 cases. At last follow-up, according to Knirk criterion for osteoarthritis, there were 22 cases of grade I and 5 cases of grade II, and all were classified as type C. CONCLUSION: Internal fixation of distal radial fractures with 2.4 mm locking plate system provided a stable fixation with good clinical outcomes.