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.

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.

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.

A comparison of classical and anatomical total knee alignment methods in robotic total knee arthroplasty: classical and anatomical knee alignment methods in TKA.

The purpose of this study was to compare the clinical and radiological outcomes achieved using classical and anatomical alignment methods in primary total knee arthroplasty (TKA). One hundred and seventeen patients were randomly assigned to undergo robotic-assisted TKA using either the classical (56 patients) or the anatomical alignment method (61 patients). Clinical outcomes including varus and valgus laxities, ROM, HSS and WOMAC scores and radiological outcomes were evaluated after a minimum follow-up of 2 years. Varus and valgus laxity assessments showed no significant inter-group differences (P>0.05). Moreover, no significant differences were observed in ROM, HSS and WOMAC scores (P>0.05). We could not find any significant difference in mechanical alignment of the lower limb. The results of this study show that two alignment methods provide comparable clinical and radiological outcomes after primary TKA.

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.

[Management of femoral neck fracture post total knee arthroplasty].

OBJECTIVE: To investigate the risk factors, management and prognosis of femoral neck fracture post total knee arthroplasty (TKA). METHODS: From January 2003 to August 2009, 45 cases of femoral neck fracture post TKA were treated. There were 8 males and 37 females with an age range of 56 - 81 years old. Among them, there were ipsilateral (n = 36) and contralateral (n = 9) femoral neck fractures. Due to the fracture site and type, the treatment plans were formulated. And a follow-up was conducted to record the Harris hip score and complications. RESULTS: The incidence of femoral neck fracture following TKA and osteoporosis had a linear correlation. And the fracture rate increased with the aggravation of osteoporosis. The stability of ipsilateral fracture group was lower than those of contralateral fracture and no fracture groups. Except for 4 mortality cases, 41 patients were followed up for 2 to 7 years with an average period of 3.6 years. There were 12 patients in the cannulated screw fixation group. The outcomes were fracture healing (n = 5) and femoral head necrosis (n = 7). Twenty-five cases underwent femoral head replacement. And 3 died and second fracture occurred in 3 cases. Eight cases underwent total hip arthroplasty. And 1 died and there was 1 case of second fracture. The Harris scores of the cannulated screw fixation group was significantly lower than the hip replacement groups (q test, P < 0.05). COMPLICATIONS: After internal fixation, 7 cases suffered femoral head necrosis and underwent femoral head replacement. And secondary fractures after hip replacement occurred in 4 cases and they were treated by plate and cable or LISS (less invasive stabilization system) system. CONCLUSION: Femoral neck fracture following TKA is usually caused by a low-energy injury. Osteoporosis is one of its high-risk factors. Knee instability is associated with ipsilateral femoral neck fracture. Clinically it can be treated by internal fixation or hip arthroplasty. And internal fixation of femoral neck fracture frequently induces femoral head necrosis. And femoral head replacement is applicable.

[Management of postoperative pain after total knee arthroplasty].

OBJECTIVE: To evaluate causes and clinical management of postoperative pain after total knee arthroplasty (TKA). METHODS: From January 2004 to June 2009, 41 patients (44 knees) with knee pain post TKA were treated. There were 9 male and 32 female patients aging from 51 to 84 years with a mean of 63.5 years. The diagnosis followed to Brown diagnostic system. One case of extraarticular pain was complex regional pain syndrome type 1 (CRPS-1) and underwent conservative treatment, the remaining 5 cases were treated by surgery. Three cases of joint instability, 1 case of patellar baja, 2 cases of soft tissue impingement caused by overhang of the prosthesis, 1 case of popliteal tendon impact underwent conservative treatment, the other 27 cases underwent surgical intervention. The patients were followed up and the Knee Society Score (KSS) knee score, pain visual analog scale (VAS) score were recorded. RESULTS: Forty-one cases were followed up for 1 to 6 years. At the last time of follow-up, the 5 cases received surgical treatment to extra-articular pain showed VAS score as 2.5 ± 0.2, KSS clinical and functional score as 92.8 ± 2.6 and 89.0 ± 3.4. There was significantly difference compared with preoperative (P < 0.05). One case of CRPS-1 performed conservative treatment, the therapy was effective. In the infected 12 cases of intra-articular pain, 1 case received amputation, 3 cases received antibiotic bone cement insert, 8 cases received two stage revision. All infections were cured, and VAS score was 3.8 ± 0.2, KSS clinical score was 88.3 ± 4.6, function score was 85.0 ± 4.6 postoperatively, with significantly difference compared with preoperative (P < 0.05). In the 8 cases received conservative treatment in non-infected group, at the last time of follow-up, VAS score was 4.5 ± 0.4, KSS clinical and functional score was 85.4 ± 4.2 and 84.2 ± 2.3, with significantly difference compared with preoperative (P < 0.05). Fifteen cases underwent surgical treatment, at the last time of follow-up, VAS score was 3.4 ± 0.1, KSS clinical and functional score was 86.6 ± 5.4 and 87.1 ± 2.4, with significantly difference compared with preoperative (P < 0.05). CONCLUSIONS: Patients with knee pain post TKA need systematic assessment to identify the causes. Appropriate treatment due to the positive diagnosis generally lead to satisfactory results, surgical intervention with indefinite causes is strictly prohibited.

[Effect of posterior condylar offset on knee flexion after high-flex posterior-stabilized total knee arthroplasty].

OBJECTIVE: To determine the effect of the posterior condylar offset (PCO) on intra- and post-operative knee flexion after total knee arthroplasty (TKA) using a high-flex posterior-stabilized (PS) fixed-bearing prosthesis and to discuss it's importance in femoral prosthesis design. METHODS: The clinical and radiographic materials of 100 consecutive patients (100 knees) were prospectively studied, including 50 men and 50 women, who had undergone primary NexGen LPS-Flex TKAs for end-stage osteoarthritis. All operations were performed by a single surgeon using the same operative technique between March 2005 and October 2006. Pearson's regression analysis was used to assess the relationship between the difference in the pre- and post-operative PCO on true lateral radiographs and the change in knee range of flexion (ROF) under non-weight-bearing conditions. RESULTS: The decrease of the corrected PCO was (3.4 ± 3.3) mm compared with the preoperative value, the restoration of PCO was better in male than female [female (-5.4 ± 3.1) mm vs. male (-1.5 ± 2.0) mm, P < 0.05]. The difference in the corrected PCO after PS TKA demonstrated significantly correlated with the change in 2 years postoperative ROF in male and female, respectively (P < 0.05). While no statistically correlation was observed in the overall group (P > 0.05). Intraoperatively, the difference in the corrected PCO was significantly correlated with the change in ROF in male, female, and the overall group, respectively (P < 0.05). CONCLUSIONS: Restoration of PCO plays an important role in the optimization of knee flexion after high-flex PS TKA. Femoral components based on Caucasian anatomic characteristics could not match the native anatomy of distal femurs of Chinese population especially female Chinese. Rotated resection of distal femur with anterior referencing technique usually leads to a decreased PCO and therefore reduces maximal obtainable flexion. Sexual dimorphism in humans and anatomic variations in various ethnic groups should be seriously considered in total knee prosthesis design.