Clinical applications of metagenomic next-generation sequencing in the identification of pathogens in periprosthetic joint infections: a retrospective study.

BACKGROUND: This study aimed to evaluate the application of metagenomic next-generation sequencing (mNGS) technology to identify pathogens in periprosthetic joint infection (PJI). METHODS: A retrospective analysis was conducted on 65 patients suspected of having PJI between April 2020 and July 2023. The patients were categorized into PJI (46 patients) and non-PJI (19 patients) groups based on the 2018 International Consensus Meeting criteria. Clinical data were collected, and both conventional bacterial culture and mNGS were performed. The diagnostic performance of the two methods was compared and analyzed. RESULTS: mNGS exhibited a sensitivity of 89.13%, a specificity of 94.74%, a positive predictive value of 97.62%, a negative predictive value of 78.26%, and an overall diagnostic accuracy of 90.77%. Compared to microbial culture, mNGS demonstrated superior diagnostic sensitivity while maintaining similar specificity. A total of 48 pathogens were successfully identified using mNGS, with Coagulase-negative staphylococci, Streptococci, Staphylococcus aureus, and Cutibacterium acnes being the most common infectious agents. Notably, mNGS was used to identify 17 potential pathogens in 14 culture-negative PJI samples, highlighting its ability to detect rare infectious agents, including Cutibacterium acnes (n = 5), Granulicatella adiacens (n = 1), Mycobacterium tuberculosis complex (n = 1), and Coxiella burnetii (n = 1), among others, which are not detectable by routine culture methods. However, mNGS failed to detect the pathogen in 4 culture-positive PJI patients, indicating its limitations. Among the 46 PJI patients, 27 had positive culture and mNGS results. The results of mNGS were concordant with those of culture at the genus level in 6 patients with PJI and at the species level in 18 patients. Furthermore, the present study revealed a significantly greater proportion of Staphylococcus aureus in the sinus tract group (45.45%) than in the non-sinus tract group (14.29%), indicating the association of this pathogen with sinus formation in PJI (P = 0.03). Additionally, there was no significant difference in the occurrence of polymicrobial infections between the sinus tract group (27.27%) and the non-sinus tract group (33.33%) (P = 0.37). CONCLUSIONS: Metagenomic next-generation sequencing can serve as a valuable screening tool in addition to traditional culture methods to improve diagnostic accuracy through optimized culture strategies.

Is AI 3D-printed PSI an accurate option for patients with developmental dysplasia of the hip undergoing THA?

BACKGROUND: In traditional surgical procedures, significant discrepancies are often observed between the pre-planned templated implant sizes and the actual sizes used, particularly in patients with congenital hip dysplasia. These discrepancies arise not only in preoperative planning but also in the precision of implant placement, especially concerning the acetabular component. Our study aims to enhance the accuracy of implant placement during Total Hip Arthroplasty (THA) by integrating AI-enhanced preoperative planning with Patient-Specific Instrumentation (PSI). We also seek to assess the accuracy and clinical outcomes of the AI-PSI (AIPSI) group in comparison to a manual control group. METHODS: This study included 60 patients diagnosed with congenital hip dysplasia, randomly assigned to either the AIPSI or manual group, with 30 patients in each. No significant demographic differences between were noted the two groups. A direct anterior surgical approach was employed. Postoperative assessments included X-rays and CT scans to measure parameters such as the acetabular cup anteversion angle, acetabular cup inclination angle, femoral stem anteversion angle, femoral offset, and leg length discrepancy. Functional scores were recorded at 3 days, 1 week, 4 weeks, and 12 weeks post-surgery. Data analysis was conducted using SPSS version 22.0, with the significance level was set at α = 0.05. RESULTS AND CONCLUSION: The AIPSI group demonstrated greater prosthesis placement accuracy. With the aid of PSI, AI-planned THA surgery provides surgeons with enhanced precision in prosthesis positioning. This approach potentially offers greater insights and guidelines for managing more complex anatomical variations or cases.

Subtrochanteric Osteotomy in Direct Anterior Approach Total Hip Arthroplasty for Crowe IV Dysplasia-Surgical Technique and Literature Review.

For Crowe IV dysplasia, the clinical efficacy and surgical technique of subtrochanteric osteotomy (SO) within the direct anterior approach total hip arthroplasty (DAA-THA) was a subject of debate. This study aimed to describe the surgical technique and clinical outcomes in 11 cases of SO in DAA-THA and to summarize the relevant literature on this topic. Between June 2016 and June 2023, we retrospectively evaluated patients diagnosed with Crowe IV hip dysplasia at our institution. Criteria identified 11 patients who underwent SO during DAA-THA. Comprehensive data encompassing demographic information, radiological data, prosthetic implant type, and surgical intricacies were collected. In addition, an exhaustive review of existing case series literature was undertaken utilizing the PubMed databases. There were no revisions, deaths, dislocations, or infections. One hip (9.09%) had an intraoperative proximal split fracture, two hips (18.2%) had lower limb deep vein thrombosis, and one hip (9.09%) had symptoms of femoral nerve injury. Radiological data showed improved bilateral femoral offset, leg length discrepancy, and anatomical acetabular. During the mean follow-up of 2.18(1.06-2.46) years, patients demonstrated enhanced functional outcomes, with average changes of 25.2 in the Harris hip score and 47 in the WOMAC score. Reviewing the literature, most studies have favored S-ROM prostheses and transverse osteotomy techniques. Intraoperative fractures were notably frequent, with rates peaking at 25%. Nonunion and nerve injury were secondary common complications. SO via DAA-THA may offer satisfactory clinical and radiographic outcomes, but the literature review underscores the need for heightened awareness of intraoperative fracture risk. Proximal detachment of the vastus intermedius plays a pivotal role in SO exposure through the DAA.

Clinical application of artificial intelligence-assisted three-dimensional planning in direct anterior approach hip arthroplasty.

PURPOSE: The objective of this study was to investigate the efficacy of an artificial intelligence-assisted 3D planning system (AIHIP) in total hip arthroplasty by direct anterior approach and assess the reliability of the AIHIP preoperative program in terms of both interobserver and intraobserver agreement. METHODS: A retrospective analysis was conducted on patients who underwent unilateral primary THA via direct anterior approach from June 2019 to March 2022. Participants were randomly assigned to receive either the AIHIP system (n = 220) or the 2D template (control group) (n = 220) for preoperative planning. The primary outcome aimed to evaluate the correspondence between the prosthesis selected intro-operation and the one planned preoperatively, as well as to calculate the intraclass correlation coefficient (ICC). Secondary outcomes included operation time, intraoperative blood loss, fluoroscopy times, Harris hip score (HHS), lower limb length difference (LLD), femoral offset (FO), and bilateral femoral offset difference. RESULTS: No significant differences were observed in gender, age, body mass index (BMI), aetiology, and American Society of Anesthesiologists (ASA) score between the two groups. Both planning methods exhibited good intraobserver agreement for component planning (ICC: 0.941-0.976). Interobserver agreement for component planning was comparable between the two methods (ICC: 0.882-0.929). In the AIHIP group, the accuracy of acetabular cup and femoral stem prosthetics planning significantly improved, with accuracies within the size range of ± 0 and ± 1 being 76.8% and 90.5% and 79.5% and 95.5%, respectively. All differences between two groups were statistically significant (p < 0.05). Patients receiving AIHIP preoperative planning experienced shorter operation times, reduced intraoperative blood loss, fewer fluoroscopy times, and lower leg length discrepancy (LLD) (p < 0.05). Moreover, they demonstrated a higher Harris hip score (HHS) at three days post-surgery (p < 0.05). However, no significant differences were found in femoral offset (FO), difference of bilateral femoral offsets, and HHS at 1 month after the operation. CONCLUSION: Utilizing AIHIP for preoperative planning of direct anterior approach THA can significantly enhance the accuracy of prosthetic sizing with good reliability, decrease operation time, reduce intraoperative blood loss, and more effectively restore the length of both lower limbs. This approach has greater clinical application value.

The compared study about femoral stem malalignment with or without the special curved rasp during DAA total hip arthroplasty.

OBJECTIVE: To investigate whether the application of a curved rasp on the femoral side is effective in reducing the incidence of stem malalignment in total hip replacement with direct anterior approach (DAA-THA), followed by the analysis of the independent risk factors affecting stem malalignment. METHODS: Retrospective analysis was carried out covering 160 patients undergoing DAA-THA from January 2019 to December 2021, with Tri-Lock (BPS, Depuy) stem applied in all 113 patients were screened according to inclusion and exclusion criteria. The data of gender, age, body mass index, preoperative diagnoses, Dorr classification, FAR ratio, pelvic morphology ratio, WOMAC scores, were analyzed to explore the independent factors influencing the malalignment of the femoral prosthesis implantation. Then data of patients were divided into group A and group B according to whether the curved rasp was taken during the operation. The chi-square test was performed to compare the incidence of femoral stem malalignment between the two groups. RESULTS: There revealed two independent risk factors: BMI and FAR ratio that affected femoral stem malalignment. The increased BMI was associated with a higher probability of femoral stem malalignment (P<0.05), the probability of malalignment of femoral stem in FAR ratio<1 was 1.15 times higher than that in FAR>1(OR = 1.15, 95% CI: 1.03-1.28, P<0.05). Further grouping analysis showed that the incidence of femoral stem malalignment in patients with intraoperative application of curved rasp was 27%, while in patients without curved rasp, the incidence of femoral stem malalignment increased significantly to 48.7%(P<0.05). The placement angle of prosthesis in group A was significantly better than that in group B, especially mild femoral stem malalignment (0%) and severe femoral stem malalignment (2.70%), and the difference was statistically significant (P < 0.05). There found no significant difference in age, gander, intraoperative complications and last follow-up assessment of WOMAC scores between the two groups of patients. CONCLUSIONS: In DAA-THA, BMI and FAR ratio act as the independent risk factors for femoral stem malalignment. Intraoperative use of a curved rasp significantly reduces the incidence of malalignment of the femoral stem.

Superficial mycosis, at the site or distant to the surgical site, appears to predispose patients to bacterial periprosthetic joint infections.

BACKGROUND: It is traditionally believed that presence of fungal infection in the nail or skin of patients is a risk factor for subsequent infection. The literature is devoid of any evidence to confirm or refute this belief. This study examined a possible relationship between the presence of superficial skin or nail mycoses and subsequent periprosthetic joint infection (PJI) in patients undergoing total joint arthroplasty (TJA). METHODS: This is a single-centre, retrospective study of patients who underwent primary TJA between 2000 and 2018. 55 patients with superficial mycoses of skin or nail, at the time of arthroplasty were identified and a variable number matching with up to a 1:5 ratio was performed with 182 patients undergoing TJA who had no superficial mycosis. The groups were further divided into knee and hip TJA. The outcome of TJA in the cohorts was compared. RESULTS: Preoperative demographics were similar between the 2 groups. The incidence of PJI in patients undergoing TKA within a year was significantly higher in patients with superficial mycosis at 8.6% (3/35) compared to 0% (0/120) in patients without mycosis. However, all infections were caused by bacterial species and none were fungal. Multiple regression analysis demonstrated that the presence of superficial mycosis had a strong correlation with development of PJI postoperatively in our TKA cohort. CONCLUSIONS: Identification of fungal infection (mycosis) of skin and nail in patients awaiting TJA is important. These patients appear to have a higher risk for developing bacterial PJI than those without fungal infections. Further study is needed to determine if treatment of these patients prior to arthroplasty stands to reverse the high risk for PJI that these patients carry.

Direct anterior versus posteriorlateral approachs for clinical outcomes after total hip arthroplasty in the treatment of severe DDH.

BACKGROUND: The total hip arthroplasty (THA) has gained popularity in in the treatment of severe developmental dysplasia of the hip (DDH). the posterior lateral approach (PLA) has good clinical efficacy and has been confirmed by the majority clinicians. Nevertheless, controversy exists regarding longer-term benefits of the direct anterior approach (DAA). The objective of this study was to investigate the clinical efficacy and placement of S-ROM prosthesis in the treatment of severe DDH by The total hip arthroplasty (THA) with different surgical approaches. METHODS: A retrospective analysis was performed on 42 patients with severe DDH admitted to our hospital from August 2015 to February 2022, who were treated with S-ROM prosthesis for total hip arthroplasty and subtrochanteric osteotomy of the femur. They were divided into DAA group and PLA group according to different surgical approaches. Perioperative indicators and imaging data were collected. RESULTS: The surgery time, intraoperative blood loss, and creatine kinase difference in DAA group and PLA group was without a statistically significant difference (P > 0.05). The postoperative length of hospitalization was shorter in the DAA group than in the PLA group (6.50 ± 3.15 vs 9.18 ± 4.93, P = 0.045). The acetabular abduction angles、the acetabular anteversion angles, the safe area ratio, The difference of femoral eccentricity, and the vertical difference of rotation center in DAA group and PLA group, there was no statistical significance (P > 0.05). Statistically significant differences were detected the horizontal difference of rotation center (P = 0.044). CONCLUSIONS: Total hip arthroplasty with S-ROM prosthesis is a feasible procedure for severe dysplastic DDH. The clinical efficacy and prosthesis placement parameters of DAA approach are advantage to those of PLA approach.

Learning Curve of Total Hip Arthroplasty in Direct Anterior Approach without Requiring Corrective Osteotomy for Hip Dysplasia.

OBJECTIVE: To explore the learning curve of total hip arthroplasty in direct anterior approach (DA-THA) without requiring corrective osteotomy for patients with unilateral developmental dysplasia of the hip (DDH) through the evaluation of clinical and radiographic results. METHOD: From December 2015 to January 2021, we retrospectively evaluated a surgeon's first 100 patients with unilateral hip dysplasia (Crowe I-III) who underwent DA-THA. All procedures were performed by a fellowship-trained joint surgeon. Cementless hemispheric porous-coated acetabular cups and tapered cementless stems were used in all hips. The radiographic data, including leg length, the height of the center of rotation, femoral head offset, the cup anteversion and inclination angle, were measured. The cumulative sum analysis (CUSUM) and risk-adjusted cumulative sum analysis (RA-CUSUM) were used to determine the learning curve of DA-THA for each patient's operation time. By analyzing the operation time, complication rate, postoperative length of hospitalization and creatine kinase (before surgery and the third day after surgery), estimated blood loss, Harris score, radiographic data were compared between the different stages of the learning curve. RESULTS: The mean follow-up time was 35.45 ± 16.82 months. The CUSUM method obtained the maximum turning point of the curve at 43 cases, which divided the learning curve into Learning Period and Mastery Period. The CUSUM learning curve was best modeled as a cubic curve with the equation: CUSUM (min) = 0.001x3 - 0.495x2 + 33.60x - 10.00, which had a higher R2 value of 0.967. The pre-operative data, creatine kinase, estimated blood loss and postoperative Harris scores of the two stages were not statistically significant (P > 0.05). The mean operation time was 118 min in the Learning Period and 87 min in the Mastery Period. Statistically significant differences were detected in the operation time (P < 0.001), postoperative length of hospitalization(P = 0.024), and postoperative leg length discrepancy (P = 0.012) between the two stages. The overall complication rates were 27.9% in the Learning Period and 12.3% in the Mastery Period (p = 0.049). The overall outliers of radiographic data were 34 cases in the Learning Period and 31 cases in the Mastery Period (79.07% vs 54.39%, P = 0.010). CONCLUSIONS: The DA-THA is a valuable alternative to achieve satisfactory clinical results for mild-to-moderate DDH patients. Furthermore, accurate analysis of the learning curve of DA-THA for hip dysplasia by the CUSUM method showed that the surgeons need to finish about 43 cases to master the technique.

Direct anterior approach for total hip arthroplasty with patients in the lateral decubitus versus supine positions: A prospective, double-blinded, randomized clinical trial.

PURPOSE: The direct anterior approach (DAA) for total hip arthroplasty (THA) can be performed with patients in either in the lateral decubitus or supine position. Prompted by the lack of studies addressing differences between the two positions, this investigation aimed to examine clinical and radiographic outcomes and compare the lateral decubitus versus the supine position for THA using the DAA. METHODS: Between January 1 and October 1, 2020, 90 patients who underwent primary unilateral THA using the DAA were recruited, with 54 (60%) undergoing THA in the supine position (SP group) and 36 (40%) in the lateral decubitus position (LP group). Technical information, clinical and radiographic outcomes, and patient-reported outcomes, including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short-Form-12 (SF-12) were evaluated. All data were subjected to several statistical tests. RESULTS: There were no preoperative differences in baseline characteristics between the LP and SP groups, which were also similar in terms of operative duration, length of hospital stay, and blood loss. Radiographic assessment confirmed satisfactory positioning of the prosthesis in both groups. There were no significant differences in terms of CK-MB and hemoglobin levels, Harris Hip Score, WOMAC, UCLA, visual analog scale score, and SF-12. The incidence of complications in the LP group was lower than in the SP group. CONCLUSION: Total hip arthroplasty performed via DAA in the LP and SP groups yielded excellent clinical outcomes, although the incidence of complications in the former was lower than in the latter.

Fungal periprosthetic joint infection: Rare but challenging problem.

Periprosthetic joint infection (PJI) is the most difficult complication following total joint arthroplasty. Most of the etiological strains, accounting for over 98% of PJI, are bacterial species, with Staphylococcusaureus and Coagulase-negative staphylococci present in between 50% and 60% of all PJIs. Fungi, though rare, can also cause PJI in 1%-2% of cases and can be challenging to manage. The management of this uncommon but complex condition is challenging due to the absence of a consistent algorithm. Diagnosis of fungal PJI is difficult as isolation of the organisms by traditional culture may take a long time, and some of the culture-negative PJI can be caused by fungal organisms. In recent years, the introduction of next-generation sequencing has provided opportunity for isolation of the infective organisms in culture-negative PJI cases. The suggested treatment is based on consensus and includes operative and non-operative measures. Two-stage revision surgery is the most reliable surgical option for chronic PJI caused by fungi. Pharmacological therapy with antifungal agents is required for a long period of time with antibiotics and included to cover superinfections with bacterial species. The aim of this review article is to report the most up-to-date information on the diagnosis and treatment of fungal PJI with the intention of providing clear guidance to clinicians, researchers and surgeons.

Influence of sagittal degenerative spondylolisthesis on anteversion of the acetabular component in total hip arthroplasty.

BACKGROUND: Degenerative lumbar spondylolisthesis (DSPL), as opposed to other degenerative spinal conditions, is disregarded in the assessment of hip stability after total hip arthroplasty (THA). This study aimed to determine whether patients with DSPL have different acetabular anteversion compared to patients with normal spine before and following THA. METHODS: Preoperative and postoperative 6­month lateral pelvic radiographs in standing and sitting positions from 91 patients who underwent primary THA were retrospectively compared for spinopelvic parameters between patients with DSPL (n = 31) and with normal spine (n = 34). RESULTS: Compared to control patients in the standing position, patients with DSPL had significantly increased preoperative pelvic tilt (24° in DSPL vs. 8° in controls; p < 0.01), pelvic-femoral angle (194° in DSPL vs. 174° in controls; p < 0.05), decreased lumbar lordosis (35° in DSPL vs. 43° in controls; p < 0.05), increased postoperative pelvic tilt (22° in DSPL vs. 7° in controls; p < 0.01), pelvic-femoral angle (187° in DSPL vs. 179° in controls; p < 0.05), and acetabular anteversion (31° in DSPL vs. 23° in controls; p < 0.05). Preoperative (p = 0.181) and postoperative (p = 0.201) sitting pelvic tilt did not differ. There were positive correlations between preoperative standing pelvic tilt and postoperative standing acetabular anteversion, pelvic-femoral angle, and combined sagittal index (CSI) in DSPL (R2 = 0.8416; R2 = 0.9180; R2 = 0.9459, respectively, p < 0.01) and in controls (R2 = 0.6872; R2 = 0.6176; R2 = 0.7129, respectively, p < 0.01). CONCLUSION: While the imbalance of seated sagittal plane is usually insignificant and compensable, the mechanism by which DSPL patients achieve a standing posture is different from control patients, with more hip extension and posterior tilt of the pelvis. Special attention should be paid to the risk of impingement caused by the increase of acetabular anteversion in the postoperative standing position.

The effect of musical interventions in improving short-term pain outcomes following total knee replacement: a meta-analysis and systematic review.

BACKGROUND: A growing number of patients continue to receive total knee replacement (TKR) surgery. Nevertheless, such surgeries result in moderate to severe postoperative pain and difficulty in managing it. Musical interventions are regarded as a type of multimodal analgesia, achieving beneficial results in other clinical treatments. This study aims to evaluate the effect of musical interventions in improving short-term pain outcomes following TKR in order to determine a more reasonable and standard way of delivering musical intervention. METHODS: A systematic search was conducted to identify available and relevant randomized controlled trials (RCTs) regarding musical interventions compared against non-musical interventions in patients treated with TKR in Embase, MEDLINE, Cochrane Library, Web of Science, CNKI, and Wanfang Med Online up to 8 January 2020. The authors independently assessed study eligibility and risk of bias and collected the outcomes of interest to analyze. The statistical analysis was conducted using the Review Manager (RevMan) version 5.30 software. RESULTS: Eight RCTs comprised of 555 patients satisfied the inclusion criteria and were enrolled in the present study. The results showed no significant difference between the music and control groups in pain of the visual analog scale (VAS), during postoperative recovery room, back to the ward after surgery; anxiety degree of VAS; heart rate; respiratory rate; oxygen saturation; blood pressure, systolic blood pressure, and diastolic blood pressure. Nevertheless, significant differences were observed between the two groups in average increase in continuous passive motion (CPM) angles and LF/HF ratio (one kind index of heart rate variability). CONCLUSIONS: Musical interventions fail to demonstrate an obvious effect in improving short-term pain outcomes following TKR. A reasonable standardization of musical interventions, including musical type, outcome measures used, outcomes measured, duration, timing and headphones or players, may improve pain outcomes with certain advantages and should be further explored after TKR.

Improved osteogenic activity and inhibited bacterial biofilm formation on andrographolide-loaded titania nanotubes.

BACKGROUND: Delivery of local drugs with a titania nanotube is an attractive approach to combat implant-related infection. Our earlier study has confirmed that nanotubes loaded with gentamicin could significantly improve the antibacterial ability. On this basis, the used andrographolide in this paper has a high antibacterial activity, which cannot only avoid the evolution of antibiotic-resistant bacteria but also has simultaneously excellent biocompatibility with osteogenic cells. METHODS: Two mg of andrographolide was loaded into titania nanotubes, which were fabricated into different diameters (50 and 100 nm) and 200 nm length by the method of lyophilization and vacuum drying. We chose a standard strain, Staphylococcus epidermidis (American Type Culture Collection 35984), and two clinical isolates, S. aureus 376 and S. epidermidis 389 to research the bacterial adhesion at 6, 12 and 24 hours and biofilm formation at 48, and 72 hours on the andrographolide-loaded nanotubes (NT-A) using the diffusion plate method. Smooth titanium (smooth Ti) and nanotubes with no drug loading (NT) were also inclusive and analyzed. Furthermore, the Sprague-Dawley (SD) rats mesenchymal stem cells were used to assess the influence of nanotubular topographies on the osteogenic differentiation of mesenchymal stem cells. RESULTS: Our results showed that NT-A could inhibit bacterial adhesion and biofilm formation on implant surfaces. NT-A and NT, especially those with 100 nm diameters, were found to significantly promoted cell attachment, proliferation, diffusion, and osteogenic differentiation when compared with smooth Ti, while the same diameter in NT-A and NT did not differ. CONCLUSIONS: Titania nanotube modification and andrographolide loading can significantly improve the antibacterial ability and osteogenic activity of orthopedic implants. Nanotubes-based local delivery could be a promising strategy for combating implant-associated infection.

Porous-coated metaphyseal sleeves and MBT implant for severe bone loss in revision total knee arthroplasty: a mean 2.4-year follow-up.

BACKGROUND: Porous-coated metaphyseal sleeves are designed to fill bone loss and facilitate osseo-integration when bone loss occurs during revision total knee arthroplasty (TKA). The purpose of this paper was to evaluate the clinical and radiographic outcomes of porous-coated metaphyseal sleeves for severe bone loss in revision TKA. METHODS: Form December 2014 to March 2018, we retrospectively analyzed 36 patients receiving revision TKAs. They had Anderson Orthopaedic Research Institute (AORI) Type II and III tibial bone loss and were treated with metaphyseal sleeve. The patients were followed up for a mean time of 28.5 months. The Knee Society Score (KSS), the Hospital for Special Surgery (HSS) Knee Score, Visual Analog Scale (VAS) score and the range of motion (ROM), radiographic findings of sleeve osteo-integration were also recorded. The paired t test was used to compare the KSS, the HSS knee score and VAS score before and after the revision TKAs. A value of P < 0.05 was considered statistically significant. RESULTS: Thirty-six patients had complete clinical and radiographic data. At the final follow-up (mean: 28.5 months), significant improvements in knee range of motion, KSS, HSS score and VAS score were observed postoperatively (P < 0.001 for all). No aseptic implant fixation failure occurred. Radiographic reviews at the final follow-up revealed that components were stable without occurrence of component migration or clinically significant osteolysis. CONCLUSIONS: This short-term retrospective study illustrated that porous-coated metaphyseal sleeves were useful in revision TKA, with a low rate of intraoperative complications, excellent osteo-integration and stable fixation.

N-Acylethanolamine acid amidase (NAAA) inhibitor F215 as a novel therapeutic agent for osteoarthritis.

Osteoarthritis (OA), characterized by cartilage damage, synovitis inflammation and chronic pain, is a common degenerative joint disease that may lead to physical disability. In the present study, we first explored the association between N-Acylethanolamine acid amidase (NAAA) and OA progression, and then examined the capability of the NAAA inhibitor F215 to attenuate osteoarthritis. Increased NAAA expressions and decreased PEA levels in synovial membrane and lumbar spinal cord were observed in MIA induced osteoarthritic rats. F215 (i.a., and i.p.) significantly protected against cartilage damage and synovial inflammation by directly increasing PEA levels in joints, or normalization of PEA levels and resolution of inflammation in spinal cord. Moreover, F215 also markedly alleviated osteoarthritic pain in rats, and the therapeutic effects of F215 were blocked by the PPAR-α antagonist MK886. The results revealed that NAAA may has been implicated in OA progression, and treatment with NAAA inhibitor F215 alleviated OA development by preventing cartilage damage, reducing inflammation, and alleviating pain. Our study suggested that NAAA inhibitor might be a novel therapeutic agent for OA treatment.

[Effects of PTHrP and Notch signaling on the proliferation of epiphysis stem cells].

OBJECTIVE: To study the regulation of the proliferation of epiphysis stem cells by the PTHrP (parathyroid hormone related peptide) and Notch signaling systems. METHODS: An organ culture system of femurs of SD rat in 24 h after birth was employed. PTHrP (1 - 34) was used as the activator of the PTHrP signaling pathway and PTHrP (7 - 34) as the antagonist of PTH (parathyroid hormone)-receptor. For Notch signaling system, Jagged1/Fc was used as the activator and DAPT as its inhibitor. The femurs were cultured in DMEM (Dulbecco's modified Eagle's medium)/F12 medium while phosphate buffered saline was used for the control groups. Hematoxylin and eosin staining and bromodeoxyuridine analysis were used to analyze the length of the epiphysis stem cells zone and the proliferation of epiphysis stem cells. The expression of NICD (Notch intra-cellular domain) and Jagged1 were analyzed by immunohistochemistry. The epiphysis stem cells were transfected with the lentiviral vectors with rat PTHrP gene overexpression or inhibition properties, the cells transfected with the PGC-GFP-lentivirus or NC-GFP-lentivirus were used as control. Western blot was employed to detect the expression of NICD and Jagged1 genes. RESULTS: PTHrP (1 - 34) and Jagged1/Fc could dramatically elevate the rate of epiphysis stem cells zone by the whole growth plate length measurement while PTHrP (7 - 34) and DAPT could decrease the rate. Brdu analysis also showed that the number of proliferative epiphysis stem cells could be up-regulated by the PTHrP (1 - 34) or Jagged1/Fc signaling. By contrast, the treatment with PTHrP (7 - 34) or DAPT reduced the number of proliferative epiphysis stem cells. Immunohistochemistry and Western blot showed a significantly elevated expression of NICD and Jagged1 when PTHrP signaling was activated while a reductive expression of NICD and Jagged1 when PTHrP signaling was inactivated. CONCLUSION: Both of PTHrP and Notch signaling system could promote the proliferation of epiphysis stem cells. And the PTHrP signaling can stimulate Notch signaling to promote the proliferation of epiphysis stem cells.