Fabrication and characterization of flexible natural cellulosic fiber composites through collaborative modification strategy of sodium hydroxide and γ-Aminopropyl triethoxysilane.

The primary purpose of this work is to study the fabrication of a flexible natural cellulosic fiber composite. In this respect, natural cellulosic fiber was obtained by modified poplar wood fiber through sodium hydroxide (NaOH) and γ-Aminopropyl Triethoxysilan. Then, the composites were fabricated by hot-pressing the modified wood fibers and polyurethane following characterization. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM) observation results confirmed that some of the hemicellulose and lignin were removed from wood fibers after NaOH modification and successfully grafted with alkoxy structures after KH550 modification. NaOH&KH550 modification improved the interfacial compatibility between poplar wood fibers and polyurethane. The flexibility of the composites was improved (the slenderness value was reduced by 113 %), allowing flexible deformations such as bending, twisting, and knotting. In addition, thermal stability, tensile strength (increased by 105 %), elongation at the break (increased by 125 %), and water resistance were increased. This flexible natural cellulosic fiber composite is expected to be applied in the veneering of curved materials and special-shaped structure furniture, providing a theoretical basis for improving the added value of wood-based composites.

Mismatched Refractive Index Strategy for Fabricating Laser-Driven Wood Diffusers from Bulk Wood for Illumination Applications.

Laser-diode-based solid-state lighting is primarily used in state-of-the-art illumination systems. However, these systems rely on light-converting inorganic phosphors, which have low quantum efficiencies and complex manufacturing conditions. In this study, a mismatched refractive index strategy is proposed to directly convert natural bulk wood into a laser-driven wood diffuser using a simple delignification and polymer infiltration method. The resulting material has the potential to be used in laser-driven diffuse illumination applications. The optical performance of the laser-driven wood diffuser is optimized by changing the density of natural wood. The optimal coefficient of illuminance variation of the wood diffuser is as low as 17.7%, which is significantly lower than that of commercial diffusers. The illuminance uniformity is larger than 0.9, which is significantly higher than the ISO requirements for indoor workplace lighting. The laser damage threshold is 7.9 J cm-2, which is considerably higher than those of the substrates of commercially available phosphors. Furthermore, the optimized wood diffuser exhibits outstanding mechanical properties, excellent thermal stability, tolerance to harsh environmental conditions, and low speckle contrast. These results show that the laser-driven wood diffuser is a promising laser-color converter that is suitable for indoor, long-distance outdoor, undersea, and other high-luminance laser lighting applications.

Using novel porous metal pillars for tibial bone defects in primary total knee arthroplasty.

BACKGROUND: The optimal method to treat tibial bone defects during primary total knee arthroplasty (TKA) is still unclear. A novel technique of porous metal pillar augmentation has been applied recently. This study aimed to assess the short-term outcomes of primary TKA with the use of novel porous metal pillars for tibial bone defects. METHODS: A total of 24 cases (22 patients) of primary TKA between January 2019 and December 2020 using porous metal pillars for tibial bone defects were reviewed. Clinical results were evaluated using the Knee Society knee score (KSKS) and function score (KSFS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and range of motion (ROM). Hip-knee-ankle angle (HKAA), femorotibial angle (FTA), and radiolucent lines were assessed radiologically. RESULTS: The median follow-up period was 36.0 months (interquartile range: 31-37 months). The KSKS, KSFS, WOMAC score, and ROM improved significantly at the final follow-up assessment compared with the preoperative evaluation. Both of the HKAA and FTA were corrected after surgery. Only one knee had a nonprogressive radiolucent line at the bone-cement interface. No radiolucent lines were detected around the pillar in any of the cases. There were no cases of prosthesis loosening and revision. CONCLUSIONS: The use of novel porous metal pillars yielded satisfactory clinical outcomes and reliable radiological evidence of fixation in this study with a minimum 2-year follow-up. Porous metal pillar augmentation can be considered as a valuable and easy-to-use method for the management of tibial bone defects in primary TKA.

[Short-term effectiveness of medial unicompartmental knee arthroplasty in patients younger than 60 years of age].

Objective: To compare the short-term effectiveness of medial unicompartmental knee arthroplasty (UKA) between patients younger or older than 60 years of age, and to investigate the impact of age on the effectiveness. Methods: The clinical data of 182 patients (182 knees) who underwent medial UKA between July 2016 and June 2018 were retrospectively analyzed, of which 72 patients were less than 60 years old (group A) and 110 patients were more than 60 years old (group B). There was a significant difference in age between groups (t=-20.198, P<0.001). No significant difference was found in gender, body mass index, surgical sides, Kellgren-Lawrence grading, disease duration, and preoperative Western Ontario and McMaster University Osteoarthritis Index (WOMAC) score between groups (P>0.05). The postoperative hospital stay and complications were recorded, and the WOMAC score, satisfaction score, and prosthesis revision were compared between groups. Results: The length of postoperative hospital stay was (4.50±1.09) days in group A, and (4.46±1.29) days in group B, with no significant difference between groups (t=0.198, P=0.844). All incisions healed by first intention. The incidences of early postoperative complications in groups A and B were 5.6% and 3.6%, respectively, and the difference was not significant (χ2=0.061, P=0.804). All patients were followed up. The follow-up time were 28-50 months (mean, 36 months) in group A and 28-50 months (mean, 35 months) in group B. At last follow-up, the WOMAC scores of both groups significantly improved when compared with those before operation (P<0.05), and there was no significant difference between groups (P>0.05) in the difference before and after operation. The satisfaction scores were 6.6±1.7 in group A and 6.9±1.6 in group B, with no significant difference between groups (t=-1.326, P=0.186). There was no revision surgery in both groups during follow-up period. Conclusion: Age has no significant effect on the prognosis of medial UKA, and patients younger than 60 years of age can also obtain good short-term effectiveness.

New Strategies and Practices of Design Education Under the Background of Artificial Intelligence Technology: Online Animation Design Studio.

This study is based on the background of how artificial intelligence (AI) technology is applied to the field of creativity and design education to improve the design vision, teaching methods, and actual design productivity of practitioners. The purpose of the research is to compare traditional design education and new design education methods combined with AI technology. Taking the Technological Pedagogical Content Knowledge (TPACK) technology integration model as the starting point, a comprehensive evaluation is selected for different types of research to explore the animation design professional courses in design education, the content of students' perception preferences, and the evaluation of ease of learning so as to conduct research and analyze AI technology. Design new education strategies and practice methods under the background. In the research, a comparative experimental study was conducted on 40 first-year students majoring in animation design. The results show that through online design studio project practice, with personalized project learning guidance, the learning needs of students to show a better trend, and customized learning and project practice content can enhance the learning experience and performance of students. In the future, we can further expand the scope of analysis, include more case studies, and conduct more comprehensive research, including how to deal with the expansion of the platform for students' learning of design in situations similar to coronavirus disease 2019 (COVID-19) that profoundly affects our lives, and how the project is applied in practice.

Patient-perceived knee enlargement after total knee arthroplasty: prevalence, risk factors, and association with functional outcomes and radiological analysis.

PURPOSE: In clinical practice, many patients complained that their knees became larger after total knee arthroplasty (TKA), yet no studies have described this phenomenon. We named this as "patient-perceived enlargement of knee" (PPEK). This study aimed to investigate the prevalence of PPEK after TKA; assess the association between PPEK and demographics, surgical options, or component size; assess the influence of PPEK on patient satisfaction and functional outcomes; and determine whether there was radiological difference between patients with or without PPEK. METHODS: We reviewed patients that underwent unilateral primary TKA between May 2018 and April 2019. We investigated the prevalence of PPEK and acquired functional scores and satisfaction. Patients were divided into two groups according to whether they complained of PPEK. In radiological evaluation, we measured anterior and posterior condyle offset (ACO and PCO) of the femur, tibial coverage lines, tibial overhanging lines, and femoral overhanging lines. RESULTS: A total of 389 patients were enrolled and 101 patients felt their knee became "larger" after TKA. Patients with PPEK had significantly shorter height and lower weight, yet component size distribution showed no statistical difference. Patients with PPEK had significantly lower functional scores and satisfaction. Patients with PPEK had significantly larger ACO, shorter postoperative PCO, more ACO increase, and less anterior underhang of the tibia. CONCLUSION: PPEK is common in TKA patients, especially in individuals with smaller height and weight. PPEK is associated with poor satisfaction and lower functional scores. In radiology, post-operative ACO, PCO, and anterior underhang of the tibial component were correlated with PPEK.

Better PROMs and higher return-to-sport rate after modular bicompartmental knee arthroplasty than after total knee arthroplasty for medial and patellofemoral compartment osteoarthritis.

Background: Theoretical advantages of bicompartmental knee arthroplasty (BKA) over total knee arthroplasty (TKA) for bicompartmental (medial combined with patellofemoral) osteoarthritis (OA) are still unclear. This study aimed to compare patient-reported outcome measures (PROMs) and return-to-sport (RTS) rate between modular BKA and TKA in early follow-up. Methods: Twenty-five consecutive modular BKA cases with a minimum 2-year follow-up were matched with 50 TKA cases at 1:2 ratio. Demographic data and preoperative functional scores, including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Knee Society Scores (KSSs), were analyzed to ensure comparability. Postoperative WOMAC score, KSS, range of motion (ROM), Forgotten Joint Score-12 (FJS-12), and RTS rates were compared. Operative time and blood loss were also analyzed. Results: Significant differences in the WOMAC-function (median 97.1 vs. 89.7, p < 0.001) and KSS-function (median 90.0 vs. 80.0, p = 0.003) scores were identified between the BKA and TKA groups. ROM was significantly greater in the BKA group than in the TKA group (median 125.0° vs. 120.0°, p = 0.004), in addition to the FJS-12 (median 89.6 vs. 53.1, p < 0.001). The overall RTS rate was significantly higher in the BKA group than in the TKA group (71.6% vs. 56.5%, p = 0.039). Operative time was significantly longer in the BKA group than in the TKA group (median 105.0 vs. 67.5 min, p < 0.001), but blood loss was similar (median 557.6 vs. 450.7 ml, p = 0.334). Conclusion: Modular BKA demonstrated better functional recovery, better joint perception, and higher RTS rate than TKA; thus, modular BKA can be a good alternative for bicompartmental OA.

[Short-term effectiveness of novel computer navigation system assisted total knee arthroplasty].

OBJECTIVE: To investigate the short-term effectiveness of novel computer navigation system (Knee 3 software; Brainlab, Germany) assisted total knee arthroplasty (TKA). METHODS: Between July 2020 and December 2020, 19 patients underwent unilateral TKA assisted with Knee 3 software. There were 4 males and 15 females. The mean age was 66.3 years (range, 52-79 years). Eighteen patients were diagnosed with osteoarthritis and 1 patient with rheumatoid arthritis. Sixteen patients had varus knees and 3 patients had valgus knees. Preoperative Western Ontario and McMaster University Osteoarthritis Index (WOMAC) pain, stiffness, function, and total scores were 12.4±3.4, 2 (1, 4), 22 (18, 29), and 37 (29, 43), respectively. Intraoperatively, the medial and lateral gaps in knee extension and in 90° of knee flexion were recorded. The operation time, intraoperative blood loss, blood transfusion, and complications were recorded. The hip-knee-ankle angle (HKA), lateral distal femoral angle, and medial proximal tibial angle were measured to evaluate lower limb alignment and prostheses's alignment using X-ray films at 6 weeks after operation. Patient's satisfaction rate and WOMAC pain, stiffness, function, and total scores were investigated. RESULTS: Eighteen patients (94.7%) had medial- lateral gap balancing in knee extension, 18 patients (94.7%) had medial-lateral gap balancing in 90° of knee flexion, 19 patients (100%) had medial gap balancing between knee extension and 90° of knee flexion, and 18 patients (94.7%) had lateral gap balancing between knee extension and 90° of knee flexion. The mean operation time was 126 minutes (range, 100-200 minutes). The mean intraoperative blood loss was 205 mL (range, 100-400 mL). Patients were followed up 4-8 months, with an average of 6.2 months. Postoperative complications included 1 deep vein thrombosis of lower extremities and 1 cerebral infarction. X-ray films showed that the mean HKA, lateral distal femoral angle, and medial proximal tibial angle were 179.8° (range, 178°-182°), 83.5° (range, 80°-87°), and 89.5° (range, 87°-93°), respectively. At last follow-up, WOMAC pain, stiffness, function, and total scores were 3.6±1.9, 0 (0, 2), 4 (2, 6), and 9 (5, 10), respectively, which improved when compared with preoperative scores ( P<0.05). Twelve patients were very satisfied with the operation results and 7 patients were satisfied with the operation results. The overall satisfaction rate was 100%. CONCLUSION: Knee 3 software can help to obtain good gap balancing and optimal lower limb alignment, with high patient's satisfaction and good short-term effecectiveness.

Investigation of the Flame-Retardant and Mechanical Properties of Bamboo Fiber-Reinforced Polypropylene Composites with Melamine Pyrophosphate and Aluminum Hypophosphite Addition.

To improve the flame-retardant performance of bamboo fiber (BF) reinforced polypropylene (PP) composites, melamine pyrophosphate (MPP) and aluminum hypophosphite (AP) at a constant mass ratio of 2:1 were added. The influence of the MPP/AP mass fraction on the mechanical and flame-retardant properties of the BF reinforced PP composites were evaluated by mechanical testing, limiting oxygen index (LOI) and cone calorimetry. Mechanical tests demonstrate that tensile properties of BF/PP decreased with the increase of MPP/AP mass fraction, while flexural properties of composites exhibited very different tendencies. Both flexural strength and modulus increased slightly with the addition of MPP/AP at first, and then decreased significantly after a relatively high content of MPP/AP was loaded. This was due to the poor interfacial compatibility between PP and MPP/AP. The flame retardancy of BF/PP composites has been greatly improved. When 30% MPP/AP was loaded into the composites, the LOI increased to 27.2%, which was 42.4% higher than that of the composite without flame retardant addition. Cone calorimetry results indicated that MPP/AP worked in both gas and condensed phases during the combustion process. Peak heat release rate, total smoke production and mass loss of the composites were significantly reduced because of the addition of MPP/AP.

An Investigation on the Comprehensive Property Assessment and Future Directions of Single Bamboo Fiber Reinforced Polypropylene Composites Fabricated by a Non-Woven Paving and Advanced Molding Process.

The demand for eco-friendly renewable natural fibers has grown in recent years. In this study, a series of polypropylene-based composites reinforced with single bamboo fibers (SBFs), prepared by non-woven paving and a hot-pressing process, were investigated. The influence of the content of SBF on impact strength, flexural strength, and water resistance was analyzed. The properties of the composites were greatly affected by the SBF content. Impact strength increased as SBF content increased. The modulus of rupture and modulus of elasticity show an optimum value, with SBF contents of 40% and 50%, respectively. The surface morphology of the fractured surfaces of the composites was characterized by scanning electron microscopy. The composites showed poor interfacial compatibility. The water resistance indicates that the composites with higher SBF contents have higher values of water absorption and thickness swelling, due to the hydrophilicity of the bamboo fibers. The thermal properties of the composites were characterized by thermal gravimetric analysis and by differential scanning calorimetry. The thermal stability of the composites was gradually reduced, due to the poor thermal stability of SBFs. In the composites, the maximum decomposition temperature corresponding to SBF shows an increasing trend. However, the maximum decomposition temperature of polypropylene was not influenced by SBF content. The melting point of the polypropylene in the composites was lower relative to pure polypropylene, although it was not affected by increasing SBF content.

Preemptive Analgesia with Parecoxib in Total Hip Arthroplasty: A Randomized, Double-Blind, Placebo-Controlled Trial.

BACKGROUND: Total hip arthroplasty (THA) is a well-accepted surgical treatment for terminal hip diseases. OBJECTIVE: To evaluate the effect of preemptive analgesia with parecoxib in patients undergoing primary unilateral THA. STUDY DESIGN: A randomized, double-blind, placebo-controlled study. SETTING: This study was conducted at Peking Union Medical College Hospital and Beijing Jishuitan Hospital in Beijing, China. METHODS: A total of 94 patients scheduled for primary unilateral THA in 2 centers (Peking Union Medical College Hospital and Beijing Jishuitan Hospital) were randomly assigned to receive 40 mg parecoxib (n = 48) or 0.9% normal saline solution (n = 46) 30 minutes before incision. All patients received standardized intravenous patient-controlled analgesia (PCA) postoperatively. Preoperative baseline data, surgery-related conditions, postoperative Visual Analog Scale (VAS) pain score, cumulative narcotic consumption of PCA, and complications were compared between the parecoxib group and the placebo group. RESULTS: There were no significant differences in postoperative VAS pain score, cumulative narcotic consumption of PCA, proportion of analgesic remedy, and complications between the 2 groups. LIMITATIONS: Only a single dose of parecoxib was used without including a dose-dependent control group. CONCLUSION: A single dose of parecoxib 30 minutes before incision did not provide effective preemptive analgesia for the management of postoperative pain after primary unilateral THA. The possible effect of preemptive analgesia with parecoxib needs further investigation. KEY WORDS: Total hip arthroplasty, pain, parecoxib, COX-2 selective inhibitor, preemptive analgesia, clinical trial, patient-controlled analgesia, analgesics.

Conductivity Maximum in 3D Graphene Foams.

In conventional foams, electrical properties often play a secondary role. However, this scenario becomes different for 3D graphene foams (GrFs). In fact, one of the motivations for synthesizing 3D GrFs is to inherit the remarkable electrical properties of individual graphene sheets. Despite immense experimental efforts to study and improve the electrical properties of 3D GrFs, lack of theoretical studies and understanding limits further progress. The causes to this embarrassing situation are identified as the multiple freedoms introduced by graphene sheets and multiscale nature of this problem. In this article, combined with transport modeling and coarse-grained molecular dynamic (MD) simulations, a theoretical framework is established to systematically study the electrical conducting properties of 3D GrFs with or without deformation. In particular, through large-scale and massive calculations, a general relation between contact area and conductance for two van der Waals bonded graphene sheets is demonstrated, in terms of which the conductivity maximum phenomenon in GrFs is first theoretically proposed and its competition mechanism is explained. Moreover, the theoretical prediction is consistent with previous experimental observations.

In-Plane Heterostructures Enable Internal Stress Assisted Strain Engineering in 2D Materials.

Conventional methods to induce strain in 2D materials can hardly catch up with the sharp increase in requirements to design specific strain forms, such as the pseudomagnetic field proposed in graphene, funnel effect of excitons in MoS2 , and also the inverse funnel effect reported in black phosphorus. Therefore, a long-standing challenge in 2D materials strain engineering is to find a feasible scheme that can be used to design given strain forms. In this article, combining the ability of experimentally synthetizing in-plane heterostructures and elegant Eshelby inclusion theory, the possibility of designing strain fields in 2D materials to manipulate physical properties, which is called internal stress assisted strain engineering, is theoretically demonstrated. Particularly, through changing the inclusion's size, the stress or strain gradient can be controlled precisely, which is never achieved. By taking advantage of it, the pseudomagnetic field as well as the funnel effect can be accurately designed, which opens an avenue to practical applications for strain engineering in 2D materials.

Anisotropic flexible transparent films from remaining wood microstructures for screen protection and AgNW conductive substrate.

Flexible transparent conductive films or substrates prepared from plastics or cellulose are widely used in optoelectronic devices. However, all of these films or substrates are fabricated by complex and expensive methods, which consume much energy and time. In this work, we report for the first time a remarkably facile and effective approach for fabricating flexible transparent films directly from wood. The resulting films exhibit an array of exceptional optical and mechanical properties. The well-aligned cell structures in natural wood are maintained during delignification, leading to anisotropic films with high transparency (≈90% transmittance). These anisotropic films with well-aligned cell structures show mechanical tensile strengths higher than those of the original wood, and can be used as screen protection films for cellphones. Furthermore, ultrathin, highly transparent, and outstandingly conductive films have been prepared from such films and silver nanowires (AgNWs) using the Meyer technique. A conductive film with an optimal area density (341 mg m-2) of AgNWs showed outstanding synergistic properties, with a transmittance of 80% and a sheet resistance of 11 Ω sq-1, equal to the conductivity of ITO. Of importance here is that the low-cost anisotropic transparent wood film shows promising potential for electronics applications in solar cells, flexible displays, and other products.

What Is the Difference Between Modular and Nonmodular Tapered Fluted Titanium Stems in Revision Total Hip Arthroplasty.

BACKGROUND: Both modular and nonmodular tapered fluted titanium stems are used in revision total hip arthroplasty (THA), with follow-up showing good results for both stems. We aimed to determine whether there were any differences in clinical outcomes, survivorship, or frequency of complications. METHODS: A retrospective review of 160 consecutive THAs (153 patients) revised with a tapered fluted modular titanium stem from 2002 to 2014 and 129 consecutive THAs (128 patients) revised with a tapered fluted nonmodular titanium stem between 2008 and 2014 was conducted. The patient's level of satisfaction, clinical assessment, and complications were examined. A Kaplan-Meier survivorship analysis was performed with the endpoint defined as any reoperation due to septic/aseptic complications. RESULTS: Mean duration of follow-up was longer in the modular group (6.3 years) than the nonmodular group (5.0 years; P = .003). No significant group differences were found in the postoperative Harris Hip Score, the level of overall satisfaction, the 8-year cumulative survival, the rate of infection, dislocation, or postoperative periprosthetic fractures. However, intraoperative fractures occurred significantly more frequently in the modular group (16.9%) than in the nonmodular group (7.0%; P = .011), and stem subsidence was significantly less in the modular group (0.95 mm) than in the nonmodular group (1.93 mm; P = .001). Two mechanical failures associated with the modular design occurred in the modular group. CONCLUSION: Both modular and nonmodular tapered fluted titanium stems provide satisfactory midterm results in revision THA. Although tapered fluted modular stems are gaining in popularity in revision THA, tapered fluted nonmodular stems should not be disregarded as a viable alternative, especially for relatively straightforward cases.

Intrinsic Notch Effect Leads to Breakdown of Griffith Criterion in Graphene.

Due to lack of the third dimension in 3D bulk materials, the crack tip in graphene locates on several atoms implying that its fracture behavior can be closely associated with its lattice structure, i.e., the bond length and angle. As the bond length reflects the discrete nature of the atomic structure, theoretical discussion is focused on the concomitant size effect at the nanoscale with few or no reports about the influence of the bond angle. Through the comparisons between theoretical calculations and experimental data, here it is first demonstrated that the bond angle is essential for understanding the fracture behavior in graphene, serving as an intrinsic notch reducing the stress singularity near the crack tip (the intrinsic notch effect), leading to the breakdown of the Griffith criterion in graphene. The work provides a framework for the studying of the brittle fracture in 2D materials, which gives rise to the more reliable device design based on 2D materials. More importantly, the significance of the intrinsic notch effect is profound and far-reaching, paving the way to a more comprehensive and deep understanding of the mechanical properties in nano as well as nanostructured materials.

Screw-hole clusters in acetabular cups: a morphological study of optimal positioning of screw-holes.

BACKGROUND: Rigid and safe transacetabular screw fixation in total hip arthroplasty (THA) is achieved by pursuing deeper bone stock and avoiding injuries to the neurovascular structures, but these efforts can be restricted by the distribution of screw-holes on cups by the manufacturer. We therefore tried to determine: (i) optimal screw-hole positions on cups to allow anatomical placement of screws; (ii) rationality of the basic 3-screw-hole cluster on commercial cups; and (iii) the optimum method for placing commercial cups in accordance with acetabular anatomy. METHODS: Periacetabular osseous structure of 64 hips and arterial structures of 50 hips were three-dimensionally reconstructed. Simulated transacetabular screw fixation during THA was performed in these hips with 3 different screw lengths (15, 25, and 35 mm) to define deeper and safer screw trajectories. Screw-hole locations of 7 commercially available cups were measured and matched with the periacetabular anatomy. RESULTS: When the cup was placed into the acetabulum at 45° of abduction and 20° of anteversion, the optimal locations of 2 screw-holes on the cups were at 30° and 64° of latitude, with a 35° separation angle. The inversetriangle distribution pattern was safer than the triangle pattern in basic 3-screw-hole-cluster cups. When placing the commercial cups, 5°-10° of anterior rotation can be added to allow better screw trajectories. CONCLUSIONS: Our study determined optimal screw-hole positions and their distribution pattern on cups. We describe methods to place the commercial cups that are not designed according to acetabular anatomy.

Chinese patients' satisfaction with total hip arthroplasty: what is important and dissatisfactory?

Through validated self-administered questionnaires, we conducted a retrospective investigation in 818 patients (1009 hips) who underwent primary THA, to collect data on overall satisfaction plus satisfaction and importance rating for 16 specific functions and issues. Overall, 8.1% patients were dissatisfied with the surgery. The top 3 important items are pain relief, squatting, and walking. The top 3 dissatisfactory items are jogging, squatting, and rising after squatting. The strongest risk factors for dissatisfaction with walking were pain (6.1×), muscle weakness(3.7×), and LLD (3.3×). The strongest risk factors for dissatisfaction with squatting were low postoperative HHS ROM (3.7×) and muscle weakness (2.6×). For Chinese patients, ROM, muscle strength and LLD are very important.

Topography of the periacetabular bone in Chinese patients - do current cages fit?

BACKGROUND: Understanding the anatomy of the periacetabular bone is critical for designing and implanting cages, as well as reconstruction of lost periacetabular bone. We aimed to study the topography of periacetabular bone and compare it with current cages to examine their fit in a Chinese population. METHODS: We performed three-dimensional measurement on computed tomography images of 105 hemipelves to delineate the topography of the periacetabular bone. We compared the bone with digital models of commercially available cages, and divided the results into three scenarios (fit, mismatch and unfit) according to absence or existence of overhang and the extent of contouring needed after implanting the cages to the pelves. RESULTS: Our measurement provided a representation of normal topography of the periacetabular bone. Only 21% of the patients studied had commercially available cages which fit their pelves, whilst there was no cage that fitted 59% of the patients even after extensive contouring. CONCLUSION: Current acetabular cages have low fit rates for the periacetabular bone in Chinese patients.

Leg-length discrepancy after revision hip arthroplasty: are modular stems superior?

We retrospectively reviewed data for 79 consecutive patients who underwent revision hip arthroplasty using cementless femoral stems at our center between September 2008 and November 2010. Two cohorts were included, one using MP (modular) femoral stems and the other using Wagner (monoblock) femoral stems. We assessed leg-length discrepancy (LLD) before and after revision and compared the occurrence of leg-length inequality between the 2 cohorts. We found that the incidence of LLD was high in revision hip arthroplasty and that leg shortening was more common than lengthening. Both acetabular and femoral sides contributed to postoperative LLD. Appropriate placement of the femoral components was most critical in adjusting LLD. We also found that compared with monoblock stems, modular stems made adjustment of postoperative leg length easier.