Anatomical cup implantation assisted with dynamic 3D planning improves functional outcomes in primary total hip arthroplasty: A retrospective study.

BACKGROUND: Anatomical cup implantation is a promising approach in primary total hip arthroplasty (THA) and improves functional outcomes. OBJECTIVE: We aimed to evaluate the cup position and functional outcomes in primary THA with preoperative dynamic 3D planning. METHODS: We retrospectively reviewed 54 hips in 48 patients who underwent primary THA with anatomical cup implantation (mean follow-up time: 52 months). Cup positions were evaluated based on patient-specific morphology, the acetabular fossa and the combined anteversion test. Functional outcomes were assessed after THA. The paired-sample t-test was performed for surgical and contralateral native hips among 42 patients who underwent unilateral THA. RESULTS: Two hips suffered intraoperative trochanteric fracture, but no hip dislocations occurred. No patients reported groin or thigh pain, and all patients were capable of deep squatting and one-leg standing. The mean Harris hip score, WOMAC score, and physical SF-36 score were 94.46 ± 6.16, 10.41 ± 3.62, and 95.19 ± 8.74, respectively. Except for acetabular offset, THA restored biomechanics to those of contralateral native hip, including cup anteversion, abduction, femoral offset and acetabular height (P> 0.05). CONCLUSION: This study provided evidence for the application of anatomical cup implantation assisted with dynamic 3D planning in primary THA, which restored morphology and improved functional outcomes.

Experimental and Numerical Investigation on the Influence Factors of Damage Interference of Patch-Repaired CFRP Laminates under Double Impacts.

The impact responses of a patch-repaired carbon-fiber-reinforced polymer (CFRP) specimen under double impacts were compared to study the damage interference mechanism through the combination of experiment and numerical analysis. A three-dimensional finite element model (FEM) with iterative loading based on continuous damage mechanics (CDM) and a cohesive zone model (CZM) was employed to simulate the double-impacts testing with an improved movable fixture at an impact distance of 0 mm-50 mm. The influence of impact distance and impact energy on the damage interference was explored by mechanical curves and delamination damage diagrams of the repaired laminates. When impactors fell within the range of the patch with an impact distance of 0 mm-25 mm at a low level of impact energy, delamination damage of the parent plate caused by the two impacts overlapped, resulting in damage interference. With the continuing increase in impact distance, the damage interference gradually disappeared. When impactors fell on the edge of the patch, the damage area caused by the first impact on the left half of the adhesive film gradually enlarged, and as the impact energy increased from 5 J to 12.5 J, the damage interference caused by the first impact on the second impact was gradually enhanced.

DMU-Net: A Dual-Stream Multi-Scale U-Net Network Using Multi-Dimensional Spatial Information for Urban Building Extraction.

Automatically extracting urban buildings from remote sensing images has essential application value, such as urban planning and management. Gaofen-7 (GF-7) provides multi-perspective and multispectral satellite images, which can obtain three-dimensional spatial information. Previous studies on building extraction often ignored information outside the red-green-blue (RGB) bands. To utilize the multi-dimensional spatial information of GF-7, we propose a dual-stream multi-scale network (DMU-Net) for urban building extraction. DMU-Net is based on U-Net, and the encoder is designed as the dual-stream CNN structure, which inputs RGB images, near-infrared (NIR), and normalized digital surface model (nDSM) fusion images, respectively. In addition, the improved FPN (IFPN) structure is integrated into the decoder. It enables DMU-Net to fuse different band features and multi-scale features of images effectively. This new method is tested with the study area within the Fourth Ring Road in Beijing, and the conclusions are as follows: (1) Our network achieves an overall accuracy (OA) of 96.16% and an intersection-over-union (IoU) of 84.49% for the GF-7 self-annotated building dataset, outperforms other state-of-the-art (SOTA) models. (2) Three-dimensional information significantly improved the accuracy of building extraction. Compared with RGB and RGB + NIR, the IoU increased by 7.61% and 3.19% after using nDSM data, respectively. (3) DMU-Net is superior to SMU-Net, DU-Net, and IEU-Net. The IoU is improved by 0.74%, 0.55%, and 1.65%, respectively, indicating the superiority of the dual-stream CNN structure and the IFPN structure.

Pathoanatomy and Injury Mechanism of Typical Maisonneuve Fracture.

OBJECTIVE: Maisonneuve fracture is a special type of injury which are rare in clinic. The manifestation of such fractures is variable. The aim of this study is to describe the pathoanatomical features of typical Maisonneuve fracture on the basis of radiographs, computed tomography (CT) scans, magnetic resonance imaging (MRI), and intraoperative exploration findings, and to investigate the injury mechanism of this variety. METHODS: The data of 41 patients with Maisonneuve fracture from April 2014 to September 2019 were retrospectively analyzed. There were 32 males and nine females, the average age was 37.9 years (range, 18 to 61 years), the fractures occurred on the left side in 20 patients and on the right side in 21 patients. The cause of injuries were traffic accident in five patients, sprain injury in 20 patients, and falling injury from height in 16 patients. All patients underwent posteroanterior and lateral X-ray examinations of the ankle and calf. CT scan of the ankle was performed in 38 patients, including three-dimensional reconstruction in 33 patients. MRI examination of the ankle and calf was performed in 28 and five patients, respectively. Forty patients were treated with open reduction and internal fixation. The features of proximal fibular fracture, injuries of the medial and posterior structures of the ankle, injuries of the anterior inferior tibiofibular ligament and the interosseous membrane were recorded and analyzed. RESULTS: Forty-one patients had proximal one-third fractures of the fibula including six patients with fracture involving the fibular neck, 30 with proximal one-third fractures of the fibular shaft, and five with proximal-medial one-third junction fracture of the fibular shaft. Thirty-five patients (35/41, 85.37%) with injury of posterior structures, 34 patients had posterior malleolar fracture (34/41, 82.93%), and one patient had posterior inferior tibiofibular ligament rupture (1/41, 2.44%). There were 20 patients with type I fracture, four patients with type II fracture, and 10 patients with type III fracture according to the Haraguchi classification of posterior malleolus fracture. The fracture of the medial malleolus was in 30 patients (30/41, 73.17%), rupture of the deltoid ligament was in 10 patients (10/41, 24.39%), and medial structures intact were in one patient (1/41, 2.44%). All 41 patients had injury of the anterior inferior tibiofibular ligament. CONCLUSIONS: Maisonneuve fracture is characterized by fractures of the proximal fibula and the complete rupture of the anterior inferior tibiofibular ligament. Pronation-external rotation is the main injury mechanism. The manifestations of typical Maisonneuve fracture including that the fibular fracture located in proximal one-third diaphysis and the fracture line was from anterosuperior to posteroinferior.

[Application of anatomical approach osteoligaments repair technique in treatment of pronation ankle fractures].

OBJECTIVE: To investigate the safety and effectiveness of anatomical approach osteoligaments repair technique in treatment of pronation ankle fractures. METHODS: The clinical data of 53 patients with pronation ankle fractures between April 2015 and October 2016, who were treated with anatomical approach osteoligaments repair technique applied for fracture reduction and internal fixation, were analysed retrospectively. There were 35 males and 18 females with an average age of 33.1 years (range, 18-60 years). The cause of injury included traffic accidents in 27 cases, tumbling in 5 cases, fall from height in 4 cases, twisted injury in 6 cases, sports injuries in 4 cases, and bruises in 7 cases. According to Lauge-Hansen classification, there were 44 cases of pronation external rotation stage Ⅳ and 9 cases of pronation abduction stage Ⅲ. The interval between injury and operation was 4-10 days (mean, 7 days). Postoperative pain and function of ankles were assessed by American Orthopedic Foot and Ankle Score (AOFAS) and visual analogue pain scale (VAS) score. The medial clear space (MCS), tibiofibular clear space (TFCS), distal fibular tip to lateral process of talus (DFTL), the anterior and posterior tibiofibular syndesmosis distance, and the lateral malleolus twist angle were measured by X-ray films and CT of bilateral ankle joints. RESULTS: The tourniquet application time was 55-90 minutes (mean, 72.5 minutes); the frequency of fluoroscopy was 5-13 times (mean, 8.9 times). All incisions healed by first intention and no infection, deep vein thrombosis occurred after operation. All patients were followed up 28-48 months (mean, 36 months). There was no significant difference in postoperative MCS, TFCS, DFTL, the anterior and posterior tibiofibular syndesmosis distance, and the lateral malleolus twist angle between bilateral ankle joints ( P>0.05). At last follow-up, no ankle instability occurred and the degenerative changes of ankle joints (Kellgren-Lawrence grading Ⅱ) occurred in 5 cases. The average AOFAS score of the ankle joint was 90.84 (range, 85-95); mean VAS score was 1.23 (range, 0-5). The average dorsiflexion and plantar flexion of ankle joints was 20.24° (range, 15-25°) and 42.56° (range, 30-50°), respectively. CONCLUSION: Anatomical approach osteoligaments repair technique in treatment of pronation ankle fractures can expose the talocrural joint and lower tibiofibular syndesmosis clearly, repair the osteoligaments injury directly, and assist the syndesmosis and talocrural joint reduction, and decline the incidence of ankle degeneration.

Optimization of electronic prescription for parallel external fixator based on genetic algorithm.

PURPOSE: For the parallel external fixator, there are some defects, such as uneven distraction rate, unbearable pain and uncontrollable movement trajectory in practical clinical applications. In order to solve the problems, a new deformity correction algorithm, which is used to calculate the elongation of the six struts, is developed. Meanwhile, the corresponding computer software for getting the electronic prescription is developed. METHODS: First, the trajectory of the moving bone is planned by Cartesian coordinate path control. Next, the prescription is obtained from the trajectory by the inverse pose solution algorithm. Finally, the genetic algorithm is utilized to optimize the achieved prescription. From the year of 2015 to 2018, twenty-three patients with complicated tibia deformity are treated by using parallel external fixator and the developed computer software. All patients have standing, patella-forward, full-length post-operative AP and lateral radiographs of the lower limbs with the complete proximal ring for getting the deformity parameters and frame parameters. These parameters are input into the computer software to calculate a daily prescription schedule for strut adjustment. Radiographs are taken regularly to determine the effects of recovery during the correction process. RESULTS: The mean time of follow-up is 18 months (range 11-40 months). All patients reach the requirements for deformity correction, and their symptoms and appearance are improved significantly. No cases of wound infections or complications occur, and no severe pain came as well during the correction process. CONCLUSIONS: By using the computer-aided parallel external fixator for the correction of lower limb deformities, satisfactory outcomes can be achieved. Hence, this method greatly improved the treatment of these patients in a clinical application.

[Progress of total ankle arthroplasty for end-stage ankle osteoarthritis].

Objective: To review the progress of total ankle arthroplasty (TAA) in treatment of end-stage ankle osteoarthritis (AOA). Methods: The domestic and foreign literatures about TAA in recent years were reviewed. The current status and progress of TAA were summarized from the results of traditional and computer-assisted TAA clinical outcomes. Results: End-stage AOA often leads to severe pain and dysfunction, and arthrodesis is still the main selective treatment option. In recent years, with the advancement of surgical techniques and prosthesis design, TAA which can remain joint mobility has increased gradually, and the surgical results also have significant progress. Accurate prosthesis implant and mechanical alignment restoration are critical factors for TAA, and surgery-related malalignment is correlative to the prosthesis failure. Computer assisted patient-specific guide can simplify the TAA procedures and obtain the accuracy of tibia and talus osteotomy. Conclusion: The clinical efficiency of preoperative CT based patient-specific guide technology for TAA needs further clinical follow-up. Meanwhile, it is necessary to further develop intraoperative navigation and robotic surgery system suitable for TAA.

[Study on sustentaculum tali screw placement for constant fragment of calcaneal fracture].

Objective: To investigate the anatomical characters of the sustentaculum tali (ST), accurate entry point and direction for the placement of ST screw from posterior subtalar joint facet to the constant fragment (CF) in calcaneal fractures. Methods: A total of 100 patients with calcaneal fractures performed ankle CT scans were enrolled between January 2016 and April 2016. According to the inclusion criteria, the clinical data of 33 patients were analyzed, including 18 males and 15 females, with a median age of 41.0 years (range, 18-60 years). There were 16 cases on left side and 17 cases on the right side. Three-dimensional (3D) calcaneal model was reconstructed by Mimics 17.0 software, and the ST anatomical references were measured, including the length of upper and lower edge, the length and height of the midline, the horizontal angle between the midline and foot plantar surface. The parameters of the optimal entry point position (P' point) and placement angle of the ST screw were determined. The length of ST screw was also measured. The differences between males and females or left and right sides were compared. Results: The length of upper edge of the ST was (16.60±2.23) mm, lower edge (20.65±2.90) mm, midline (20.56±2.62) mm, and the height of midline was (9.61±1.36) mm. The horizontal angle between the midline and foot plantar surface was (23.43±3.36)°. The vertical distance from P' point to the lowest point of the tarsal sinus was (3.09±1.65) mm, while the horizontal distance was (14.29±2.75) mm. The distance from P' point to the apex of the lateral talus, subchondral bone of subtalar joint, calcaneocuboid joint was (11.41±3.22), (6.59±2.22), (34.58±3.75) mm, respectively. The horizontal angle between the ST screw and foot plantar surface was (-1.17±2.07)°. The anteversion angle of ST screw was (16.18±2.05)° and the length was (41.64 ± 3.09) mm. There were significant differences in the length of upper and lower edge, the length and height of the midline, the distance from P' point to the apex of the lateral talus, subchondral bone of subtalar joint, and calcaneocuboid joint, and the anteversion angle and length of the ST screw between males and females ( P<0.05). There was no significant difference in above all parameters between left and right sides ( P>0.05). Conclusion: After appropriate reduction of the calcaneal fractures, the entry point of ST screw was recommended at about 14 mm posterior and about 3 mm upper related to the foot horizontal line through the lowest tarsal sinus point; and the direction of ST screw placement was about 17° anteversion for males and 15° anteversion for females.

Long non-coding RNA ZFAS1 sponges miR-486 to promote osteosarcoma cells progression and metastasis in vitro and vivo.

Long noncoding RNAs (lncRNAs) have been wildly demonstrated to participate in the osteosarcoma tumorigenesis. ZFAS1 is a novel identified lncRNA, however, its role in osteosarcoma is still unclear. In present study, we utilize lncRNA microarray assay to screen the lncRNA expression profile in osteosarcoma tissue, and investigate the regulatory function of ZFAS1 in osteosarcoma. LncRNA microarray assay revealed that lncRNA ZFAS1 was significantly up-regulated in 3 pairs of osteosarcoma and adjacent non-tumor tissue, which was confirmed by RT-PCR. Furthermore, in 53 pairs of osteosarcoma patient samples, the up-regulated expression of ZFAS1 was closely related to poor prognosis. In vitro, loss-of-function experiments showed that ZFAS1 knockdown significantly suppressed the proliferation, induced cycle arrest at G0/G1 phase and enhance apoptosis. In vivo, ZFAS1 knockdown inhibited the tumor growth. Bioinformatics online programs predicted that ZFAS1 sponge miR-486 at 3'-UTR with complementary binding sites, which was validated using luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Rescue experiments confirmed that miR-486 could reverse the functions of ZFAS1 on osteosarcoma genesis. In conclusion, our results demonstrate that ZFAS1 act as competing endogenous RNA (ceRNA) for miR-486, and act as oncogene in osteosarcoma tumorigenesis, and discover the functional regulatory pathway of ZFAS1 sponging miR-486.

Safety and efficacy of intra-articular tranexamic acid injection without drainage on blood loss in total knee arthroplasty: A randomized clinical trial.

BACKGROUND: Major blood loss is unavoidable after primary total knee arthroplasty (TKA). The aim of this study was to determine if tranexamic acid (TXA) can reduce major blood loss following TKA. METHODS: In this double-blind, randomized, placebo-control trial, 60 patients treated with unilateral primary cement TKA between August 1st 2013 and September 30th 2013 were randomized into TXA 500 mg intra-articular injection without drainage (test group, 30 knees) and 30 patients with saline intra-articular injection (control group, 30 knees). RESULTS: There was a significant reduction in mean blood loss (560.55 mL) between the groups at postoperative day (POD) 5 (999.22 mL vs. 1559.77 mL, P = 0.001). The maximum hemoglobin drop was identified at POD 3 (10.51 g/dL vs. 9.10 g/dL, mean difference = 1.41 g/dL). Also, there was a significant reduction in red blood cell and hematocrit loss (P = 0.001). The transfusion rates (0% vs. 23.3%, P = 0.011) and average amount transfused (0.00 ± 0.00 units vs. 0.53 ± 1.04 units, P = 0.009) were significantly lower in the TXA group compared with control group. No significant difference in coagulation marker changes were found between TXA and control groups (P > 0.05), but the D-dimer levels at 3 and 5 days post-TKA were statistically lower in the TXA group (P < 0.05). No significant changes in the rate of symptomatic deep venous thrombosis, pulmonary embolism, or wound healing problems were noted. CONCLUSIONS: TXA treatment without drainage during TKA reduces the amount of blood transfusions required without increasing the rate of adverse events.

Comparison of quadriceps snip and tibial tubercle osteotomy in revision for infected total knee arthroplasty.

PURPOSE: Controversies exist regarding the ideal approach in a revision total knee arthroplasty for infection, providing adequate exposure with minimum complications. The purpose of this study was to compare the results of second stage revision total knee arthroplasty (TKA) between tibial tubercle osteotomy (TTO) and quadriceps snip (QS) approaches for infected TKA. METHODS: The clinical and radiological outcomes of 27 patients of TTO and 21 patients of QS in second stage revision TKA for infected TKA were compared with an average follow up of 51 months. We evaluated the clinical outcomes including HSS score, WOMAC score, flexion contracture, and maximal flexion between two groups. The radiological outcomes in terms of femorotibial alignment, patellar height and complications were also compared. RESULTS: At the final follow-up, KSS score, HSS score, WOMAC score, flexion contracture, and maximal flexion showed no statistically significant differences between the two groups. The femorotibial alignment and patellar height also showed no differences between the two groups. During the surgery, patellar tendon partial avulsion was more commonly observed in the QS group than in the TTO group (five vs two cases). CONCLUSION: Both tibial tubercle osteotomy and quadriceps snip in revision TKA were considered as good approaches without significant complications. However, cautious exposure of patellar tendon or strong fixation of the osteotomy is needed to minimize the complications.

[EFFECT OF MEDIAL 1/3 ANATOMICAL ORIENTATION OF TIBIAL TUBERCLE ON ROTATIONAL ALIGNMENT OF Gemini MK-II TIBIAL COMPONENTS IN TOTAL KNEE ARTHROPLASTY].

OBJECTIVE: To investigate the effect of medial 1/3 anatomical orientation of the tibial tubercie on tne rotational alignment of Gemini MK-II tibial components in total knee arthroplasty (TKA). METHODS: Between March 2011 and December 2012, 61 cases (67 knees) of varus knee osteoarthritis underwent Gemini MK-II knee arthroplasty, and the clinical data were retrospectively analyzed. There were 12 males and 49 females, with an average age of 67.6 years (range, 50-82 years). The body mass index ranged from 20.9 to 33.7 kg/m2 (mean, 28.2 kg/m2). Unilateral TKA was performed in 55 cases and bilatepal TKA in 6 cases. The duration of knee osteoarthritis ranged from 2 to 30 years (mean, 12.1 years). According to radiographic changes, 56 knees were rated as Kellgren-Lawrence grade III and 11 knees as grade IV. During TKA, the tibial rotational alignment was determined by medial 1/3 anatomical orientation of the tibial tubercle. The anteroposterior and lateral X-ray films and CT scan were taken to measure the tibial rotational angle (TRA) at pre- and post-operation and to analyze the relative factors for TRA by Pearson correlation analysis. RESULTS: All the patients were followed up 18-41 months (mean, 20.5 months). The range of motion (ROM) significantly increased from (98.806±16.969)° preoperatively to (116.806±11.458) at last follow-up (t= -11.760, P=0.000). The knee society score (KSS) significantly increased from 111.239±20.344 to 160.522±17.872 at last follow-up (t= -27.271, P=0.000). The anatomical tibiofemoral angle (ATFA), posterior condylar angle (PCA), and TRA were all improved after TKA, showing significant differences when compared with preoperative ones (P<0.05). Rotational malalignment was observed in 11 knees (16.42%). before TKA, and in 14 knees (20.90%) at 1 week after TKA, showing no significant difference (χ2=0.443, P=0.506). There were 8 knees (11.94%) of internal rotation (>8°) and 6 knees (8.96%) of external rotation (>8°). The postoperative tibial prosthesis TRA had no correlation with the preoperative ATFA and tibial plateau TRA, the postoperative PCA and ATFA (r= -0.174, P=0.159; r=0.220, P=0.074; r=0.237, P=0.053; r= -0.095, P=0.442). CONCLUSION: In patients with varus knee osteoarthritis, medial 1/3 anatomical orientation of the tibial tubercle will contribute to the development of tibial rotational malalignment when TKA is performed by using Gemini MK-II tibial components.

[Safety and efficacy of rivaroxaban for prevention of deep vein thrombosis in patients with preoperative abnormal D-dimer after total knee arthroplasty].

OBJECTIVE: To evaluate the safety and efficacy of rivaroxaban for prevention of deep vein thrombosis (DVT) in patients with preoperative abnormal D-dimer after total knee arthroplasty (TKA). METHODS: Between August and September 2013, 60 consecutive patients with varus knee osteoarthritis undergoing unilateral TKA were enrolled in the study. According to the preoperative D-dimer level, the patients were divided into 2 groups: D-dimer normal group (control group, n = 41) and D-dimer abnormal group (test group, n = 19). No significant difference was found in gender, age, body mass index, and preoperative knee range of motion between 2 groups (P > 0.05). All patients underwent conventional primary TKA and anticoagulation therapy with rivaroxaban to prevent DVT. The tourniquet use time, postoperative hospitalization time, and total hospitalization time were compared between 2 groups. At 1, 3, and 5 days after operation, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (FIB), and D-dimer were measured. Wound complications and DVT were observed. RESULTS: The postoperative hospitalization time of the test group was significantly longer than that of the control group (t = 2.327, P = 0.031), while the tourniquet use time and total hospitalization time showed no significant difference between 2 groups (P > 0.05). All the patients were followed up 6-8 months (mean, 7.2 months). Wound complications occurred in 3 cases (7.3%) of the control group and in 2 cases (10.5%) of the test group, showing no significant difference (χ2 = 0.175, P = 0.676). Color ultrasonography showed no pulmonary embolism and DVT at 6 weeks after TKA. There were significant differences in PT, TT, and FIB between at pre- and post-TKA in the same group, but no significant difference was found between 2 groups. The APTT and D-dimer had significant differences between at pre- and post-TKA in the same group, and between groups. There was no significant interaction effect between time and group for each index. CONCLUSION: Preoperative abnormal D-dimer level should not be regarded as a contraindication for TKA. The risks of DVT and wound complications in patients with abnormal D-dimer level are similar to patients with normal D-dimer level using rivaroxaban administration after TKA. It is unnecessary to conventional monitor D-dimer and other coagulation and hemorrhage laboratory tests in the patients after TKA.

Femoral stress and strain changes post-hip, -knee and -ipsilateral hip/knee arthroplasties: a finite element analysis.

OBJECTIVE: To identify the optimal ratio of free femur for minimizing the risks of periprosthetic fracture. METHODS: Three dimensional models of the femur with hip and knee stem elongation were constructed. With the distal femoral condylar surface fixed in a three dimensional model, the femoral head loading was performed according to the methods described by Huiskes and van Rietbergen in the models of hip replacement, knee replacement with or without hip stem or knee stem elongation. The maximum principal stress (MPS) and maximum principal elastic strain (MPES) of the femur were recorded and their relationships to the free femur ratio were analyzed using Pearson's correlation analysis. RESULTS: There were no obvious changes in MPS and MPES with hip stem elongation from 100 to 180 mm. In ipsilateral hip and knee replacement, the MPS and MPES had a tendency to decrease with knee and hip stem elongation. The MPS and MPES were mainly located in the anterior medial side of the middle to distal femur post-hip replacement and distalized with stem elongation. When the knee stem had been elongated more than 120 mm, the stress and strain concentrated strongly in the middle of the femoral shaft. There was a positive correlation between MPS and MPES to the free femur ratio (P < 0.01); however, no optimal ratio of free femur that would minimize the risks of periprosthetic fracture was identified. CONCLUSION: Positive correlations were found between implant free femur and stress and strain changes in total knee arthroplasty, total hip arthroplasty and ipsilateral hip and knee replacement.

[Research development of diagnosis and treatment of meniscal root tears].

OBJECTIVE: To analyze the causes of meniscal root tears (MRTs), and to review the progress in its diagnosis and therapy. METHODS: The published literature about MRTs was extensively reviewed and summarized. RESULTS: MRTs can be divided into acute traumatic injuries and chronic degenerative injuries; MRI examination is an effective way to diagnose according to meniscal extrusion, ghost sign, and meniscal root linear defects. Conservative treatments are mainly performed for chronic MRTs; partial meniscectomy can obtain predictable improvement in symptoms. Acute MRTs can be treated by arthroscopic meniscus repair and reconstruction which can effectively restore meniscal root anatomy and function, and knee joint degeneration can be postponed. CONCLUSION: MRTs diagnosis relies on MRI, appropriate treatment plan should be made based on the specific circumstances of the patient after accurate diagnosis. Usually the satisfied short-term clinical results can be obtained, while the long-term results need more clinical evaluation.

[Determination of tibial bone resection thickness by lateral tibiofemoral joint 90° flexional gap in total knee arthroplasty for varus osteoarthritic knees].

OBJECTIVE: To investigate the efficiency of total knee arthroplasty (TKA) for varus osteoarthritic knees with tibial bone resection determined by lateral tibiofemoral joint 90° flexional gap measurement. METHODS: Between March and June 2013, 60 patients (60 knees) with varus osteoarthritic knees underwent TKA. All patients were randomly divided into traditional osteotomy group (control group, 30 cases) and lateral tibiofemoral joint 90° flexional gap measurement resection group (trial group, 30 cases). There was no significant difference in gender, age, affected side, body mass index and preoperative knee society score (KSS), range of motion (ROM) of the knee, anatomic tibiofemoral angle (ATFA), patellar tilt angle, posterior condylar offset (PCO), and joint line height between 2 groups (P > 0.05). The bone resection thickness of the distal femoral lateral condyle, femoral posterior lateral condyle, and lateral tibial plateau were measured; and the X-ray films were taken to measure and compare ATFA, patellar tilt angle, PCO, and joint line height after TKA. The knee function recovery was evaluated with KSS score and ROM of the knee. RESULTS: The bone resection thickness of the lateral tibial plateau and distal femoral lateral condyle in trial group was significantly smaller than that in control group (P < 0.05); while the bone resection thickness of the femoral posterior lateral condyle was significantly bigger than that in control group (P < 0.05). The 10 mm polyethylene insert was used in 19 cases of the trial group and in 8 cases of the control group, showing significant difference (Z= -4.040, P=0.003). All the patients were followed up 13-16 months (mean, 14.5 months). Radiography at 6 weeks after TKA indicated that the ATFA, patellar tilt angle, and joint line height had no significant difference between 2 groups (P > 0.05); the PCO of trial group was significantly lower than that of control group (P < 0.05). The KSS score and ROM of the knee at 12 months after operation were significantly improved when compared with preoperative ones in 2 groups (P < 0.05), and trial group was significantly better than control group (P < 0.05). CONCLUSION: It was an effective method to determine bone resection thickness using lateral tibiofemoral joint 90° flexional gap measurement in TKA for varus osteoarthritic knees, which can reduce the bone resection thickness of the tibial plateau and distal femoral lateral condyle and restore the joint line and PCO with better early recovery of the knee function.

[Management of deep infection after total knee arthroplasty].

OBJECTIVE: To evaluate the clinical treatment methods of deep infection after total knee arthroplasty (TKA) and its effectiveness. METHODS: Between January 2004 and January 2010, 32 cases (32 knees) of deep infection after TKA were treated, including 13 males and 19 females with an average age of 64.6 years (range, 52-79 years). The time from primary TKA to infection was 3 weeks to 10 years. The preoperative knee society score (KSS) was 104.6 +/- 9.1, and the visual analogue scale (VAS) score was 7.8 +/- 1.4. Open debridement and continuous irrigation were perfomed in 3 cases of acute infection, arthroscopic debridement and irrigation in 3 cases of acute haematogenous infection; in 26 cases of chronic deep infection, 9 cases underwent open debridement, 4 cases underwent antibiotics impregnated bone cement spacer, 12 cases received two-stage revision, and 1 case underwent conservative treatment by intravenous antibiotics. RESULTS: All cases of acute infection failed to control deep infection; 1 case of acute haematogenous infection failed to treat; 7 cases of chronic infection undergoing debridement and 1 case of conservative treatment failed to treat; and all the failure cases were cured after symptomatic treatment. Thirty-two cases were followed up 2-8 years (mean, 4.6 years). At last follow-up, the KSS score and VAS score were 158.4 +/- 8.3 and 4.1 +/- 0.8, respectively, all showing significant differences when compared with preoperative scores (P < 0.05). Re-infection occurred in 3 patients who received two-stage revision during follow-up. CONCLUSION: In patients with acute infection of methicillin-resistant Staphylococcus aureus after TKA, open debridement and liner change have low success rate; arthroscopic debridement can be performed to control acute haematogenous infection; and two-stage revision is an effective method to control chronic infection and restore the knee function, but two-stage revision has a potential risk of re-infection.

Antibiotic-loaded articulating cement spacers in two-stage revision for infected total knee arthroplasty: individual antibiotic treatment and early results of 21 cases.

OBJECTIVE: To detail our early experience and technique of a modified two-stage reimplantation protocol using antibiotic-loaded articulating cement spacers (ALACSs) for treatment of late periprosthetic infection after total knee arthroplasty (TKA). METHODS: From January 2006 to February 2009, a series of 21 patients (21 knees) with late infected TKAs were treated by radical debridement and removal of all components and cement, and then articulating spacers were implanted using antibiotic-impregnated bone cement. For this purpose, 4 g vancomycin powder was mixed with per 40 g cement. Graduated knee motion and partial weight bearing activity were encouraged in the interval period. Each patient received an individual systemic organism-sensitive antimicrobial therapy for 4.9 (range, 2-8) weeks followed by a second-stage TKA revision. All the patients were regularly followed up using the American Knee Society Scoring System. RESULTS: Each case underwent a successful two-stage exchange and had infection eradicated, none had recurrent infection after an average of 32.2 (range, 17-54) months of follow-up. Preoperatively, the mean knee score was 53.5 points, function score was 27.3 points, pain score was 25.7 points, range of motion (ROM) was 82.0 degree extensor lag was 2 degree Between stages, the mean knee score was increased to 61.3 points, function score to 45 points, pain score to 35 points, ROM to 88.2 degree and extensor lag to 3.4 degree At final follow-up, the mean knee score was further increased to 82.1 points, function score to 74.5 points, pain score to 42.1 points, ROM to 94.3 degree and knee extension lag to 1.9 degree The interval period was 11.5 (range, 6-32) weeks. The amount of bone loss was unchanged between stages. No patient developed noticeable dysfunction of the liver or kidney or other complications such as impaired wound healing, deep venous thrombosis, pulmonary embolism, cerebrovascular accidents, etc. CONCLUSIONS: Treating infected TKA with ALACS avoids spacer-related bone loss, preserves knee function between stages, and eradicates infection effectively without significant complications. The early clinical results are inspiring. The authors believe that radical and repeated (if needed) debridement, individual application of systemic antibiotics, and reasonable timing judgement upon the secondary revision are all key factors related to a successful outcome with two-stage reimplantation procedure for infected TKA.

Does mismatch of the femoral component aspect ratio influence the range of knee flexion after posterior-stabilized total knee arthroplasty?

OBJECTIVE: To study whether the range of knee flexion (ROF) is affected by geometrical mismatch of the femoral component and the resultant change in the posterior condylar offset (PCO) after high-flexion posterior-stabilized total knee arthroplasty (TKA). METHODS: One hundred osteoarthritic patients (50 males and 50 females) underwent femoral osteotomy by the anterior referencing technique. The PCO for each patient was measured from lateral radiographs before, during and 2 years after TKA. The thickness of the joint cartilage was measured by magnetic resonance imaging before TKA and added onto the radiographic measurement. The relationship between changes in the PCO and improvements in the ROF before, during and 2 years after TKA were statistically analyzed. RESULTS: Compared with the preoperative value, the PCO was reduced by (3.45+/-3.28) mm after TKA, with a significantly larger reduction observed in female patients than male patients (P less than 0.05). When examining the subject population as a whole, there was a significant positive correlation between PCO and ROF improvement during TKA (P less than 0.05), but this improvement was not maintained 2 years after TKA (P larger than 0.05). However, when male and female patients were analyzed separately, there was a significant positive correlation between PCO change and ROF improvement for both sexes at both time points (all P less than 0.05). CONCLUSIONS: Restoration of PCO plays an important role in the optimization of knee flexion even after posterior-stabilized TKA. Femoral components based on Caucasian anatomic characteristics could not match the native anatomy of distal femurs in Chinese population especially female Chinese. Rotated resection of distal femur with anterior re-ferencing technique usually leads to a decreased PCO and therefore reduces maximal obtainable flexion.

[Autologous bone grafting plus screw fixation for medial tibial defects in total knee arthroplasty].

OBJECTIVE: To investigate the efficacy of autologous bone grafting plus screw fixation to reconstruct the medial tibial defects in total knee arthroplasty (TKA). METHODS: From November 2001 to November 2004, 46 patients (50 knees) with medial tibial bone defects underwent TKA at our hospital. There were 16 males (16 knees) and 30 females (34 knees). They included osteoarthritis (OA) (n = 35, 38 knees) and rheumatoid arthritis (RA) (n = 11, 12 knees). A total of 46 patients underwent three-dimensional CT (computed tomography) reconstruction to evaluate the tibial plateau defects after osteotomy. Single or double distal femoral osteotomic bone was used to reconstruct the bone defects with the hollow nail internal fixation. Another 80 TKA patients (86 knees) were randomly selected as the control group. The surgical outcome, lateral migration of tibial component and joint line elevation, etc. were analyzed and the follow-up knee society scores recorded. RESULTS: The patients were followed up for 6 to 9 years. Two patients were lost to follow-up and 1 died of myocardial infarction at 5 years post-TKA in the test group. In the last follow-up, 1 case suffered deep infections and all others had no prosthetic loosening. One case (1 knee) had resorption of wedge-shaped bone graft after 8 years. The remaining graft healed and there was no screw displacement. Medial platform split fracture occurred in 3 patients (3 knees) in the OA group. The quantity of distal femoral osteotomy, thickness of polyethylene insert, tibial implant size, joint line elevation and lateral migration of tibial base were greater than the other two groups (q test, P < 0.05). The pre- and post-operative KSS scores had significant differences in each group (F test, P < 0.05). But the same group showed no significant difference at 6, 9 years (q test, P > 0.05). CONCLUSION: As an easy and effective way of reconstructing the medial tibial bone defects, autologous bone grafting plus screw fixation can restore knee mechanical axis and stability. But in OA patients with tibial sclerosis, the complications of tibial component lateral migration, joint line elevation and splitting tibia fractures should be avoided during the reconstruction.