Pneumocystis jiroveci pneumonia after total hip arthroplasty in a dermatomyositis patient: A case report.

BACKGROUND: Pneumocystis jiroveci pneumonia (PJP) is a serious opportunistic infection that occurs mostly in patients with immunodeficiency and long-term immunosuppressive therapy. In non-human immunodeficiency virus-infected patients, the most important risk factor for PJP is the use of glucocorticoids in combination with other immunosuppressive treatments. The management of glucocorticoids during the perioperative period in patients with dermatomyositis requires special care. CASE SUMMARY: We report a case of PJP in the perioperative period. A 61-year-old woman with a history of anti-melanoma differentiation-associated gene 5 (MDA5)-positive dermatomyositis and interstitial pneumonia was administered with long-term oral methylprednisolone and cyclosporine. The patient underwent right total hip arthroplasty in the orthopaedic department for bilateral osteonecrosis of the femoral head. She was given intravenous drip hydrocortisone before anesthesia and on the first day after surgery and resumed oral methylprednisolone on the second postoperative day. On the fifth day after surgery, the patient suddenly developed dyspnea. The computed tomography scan showed diffuse grid shadows and ground glass shadows in both lungs. Polymerase chain reaction testing of bronchoalveolar lavage fluid was positive for Pneumocystis jiroveci. The patient was eventually diagnosed with PJP and was administered with oral trimethoprim-sulfamethoxazole. At the 6-mo review, there was no recurrence or progression. CONCLUSION: Continued perioperative glucocorticoid use in patients with anti-MDA5-positive dermatomyositis may increase the risk of PJP.

Robotic-assisted unicompartmental knee arthroplasty: a review.

PURPOSE: Presented here is an up-to-date review concerning robotic-assisted unicompartmental knee arthroplasty (rUKA), including its rationale, operative system, pros and cons. METHODS: We did a systematic research in electronic databases, including PubMed, Cochrane Library, Web of Science, and Embase up to March 30, 2020 to retrieve literature pertaining to rUKA. The search strategies "(robotic* AND knee arthroplasty OR knee replacement)" and "(knee arthroplasty OR knee replacement NOT total)" were used. Studies describing rUKA and clinical trials, dry bone or cadaveric researches regarding technologies, positioning, alignment, function, or survivorship of implants were included in this review. All retrieved studies were first browsed for eligibility on the basis of title and abstract, and the selected studies were further evaluated by reading full text for final inclusion. RESULTS: Robotic-assisted technology has been found to increase the accuracy of bone preparation and implant placement, reduce technical variability and outliers, and enhance reproduction of limb alignment. Additionally, early clinical outcomes were excellent, but mid-term follow-up showed no superiority in component survivorship. The potential drawbacks of the robotic-assisted technology include relatively-low time- and cost-effectiveness, development of some rUKA-related complications, and lack of support by high-quality literature. CONCLUSION: This review shows that rUKA can decrease the number of outliers concerning the optimal implant positioning and limb alignment. However, due to absence of extensive studies on clinical outcomes and long-term results, it remains unclear whether the improved component positioning translates to better clinical outcomes or long-term survivorship of the implant. Nevertheless, since an accurate implant position is presumably beneficial, robotic-assisted technology is worth recommendation in UKA.

Does new instrument for Oxford unicompartmental knee arthroplasty improve short-term clinical outcome and component alignment? A meta-analysis.

BACKGROUND: The Microplasty (MP) instrumentation designed for the Phase III Oxford mobile-bearing unicompartmental knee arthroplasty (UKA) system is considered a better option to achieve more accurate component positioning and alignment. In the present study, we focused on short-term clinical and radiological outcomes to determine whether the MP instrumentation can reduce the short-term revision rate and occurrence of outliers of metallic components. METHODS: The literature in PubMed, Embase, the Cochrane Library, and Web of Science was searched up to May 2020. Studies were scrutinized by two independent authors, and the revision rate, complication spectrum, and radiological assessment with outlier rates were specifically analyzed. RevMan 5.3 was used for the statistical analysis. RESULTS: Seven studies were included in the meta-analysis. Four studies reported both clinical and radiological outcomes, two reported only radiological outcomes, and one reported only clinical outcomes. The pooled analysis showed that the revision rate in the MP instrumentation group was 0.866 per 100 component years, while that in the control group was 1.124 (odds ratio, 0.77; p < 0.05). The subgroup analysis of the bearing dislocation rate showed a significantly greater reduction in the Korean population than in the populations of other countries (p < 0.05). The radiological assessment showed that the alignment of the femoral component was significantly improved (p < 0.05), while that of the tibial component was not (p > 0.05). CONCLUSION: The newly developed MP instrumentation for Oxford UKA significantly reduced the revision rate of this treatment. The positioning of the femoral component was also proven to be better by radiological assessments.

Role of Junction-Mediating and Regulatory Protein in the Pathogenesis of Glucocorticoid-Induced Endothelial Cell Lesions.

OBJECTIVE: Nontraumatic osteonecrosis of the femoral head (ONFH) is one of the most common diseases in orthopaedics. The damage to vascular endothelial (VE) cells caused by glucocorticoids (GC) has been reported as a possible mechanism of pathogenesis for ONFH. Junction-mediating and regulatory protein (JMY), originally identified as a p53 coactivator, plays prominent roles in the DNA damage response and in cell motility. This study aimed to discover the role of JMY in the pathogenesis of GC-induced endothelial cell lesions. METHODS: High-throughput RNA sequencing was performed to identify the differentially expressed genes between GC-treated human umbilical vein endothelial cells (HUVEC) and control cells. JMY knockdown and overexpressing HUVEC lines were treated with GC. Cell proliferation was examined with a survival cell count assay (Cell Counting Kit-8, CCK-8); cell apoptosis was measured by flow cytometry; a scarification assay was used to detect the capability of cell migration; a Transwell chamber assay was done to detect the cell motility . Differential expression of cell protein was detected by western blot. RESULTS: A total of 1561 differential genes were obtained through transcription sequencing, of which 789 mRNA were upregulated and 772 mRNA were downregulated in the GC-treated HUVEC compared with the control cells. CCK-8 assay results showed that: without GC treatment, overexpression or knockdown of JMY did not affect the proliferation activity of HUVEC. In the presence of GC treatment, the proliferation activity of HUVEC in the JMY knockdown group was significantly higher than that in the control group (P < 0.01). The proliferation activity of HUVEC in the overexpression JMY group was significantly lower than that in the control group (P < 0.01). The results of flow cytometry showed that without GC treatment, overexpression or knockdown of JMY did not affect the apoptosis proportion of HUVEC. With GC treatment, the apoptosis proportion of HUVEC in the JMY knockdown group was significantly lower than that in the control group (P < 0.01), and the apoptosis proportion of HUVEC in the overexpression JMY group was significantly higher than that in the control group (P < 0.01). Western blot results showed that with GC treatment, the JMY expression level of HUVEC increased with the reaction time. Moreover, the distribution of JMY was mainly concentrated in the nucleus. The expression level of Bax also increased with the reaction time. With GC treatment, overexpression of JMY could significantly increase the expression of Bax in HUVEC. JMY knockdown could reduce the expression of Bax in HUVEC. In the absence of GC treatment, HUVEC overexpression or knockdown of JMY did not affect the expression of Bax. The results of scarification and Transwell chamber assays showed that: without GC treatment, JMY knockdown could significantly decrease the cell motility and increase the expression level of VE-cadherin in HUVEC; with GC treatment, JMY knockdown in HUVEC had lower cell motility compared with the control group (P < 0.01). CONCLUSION: Glucocorticoids can induce the HUVEC apoptosis, and reduce its proliferation, cell motility. Our results mainly confirmed the role of JMY in the pathogenesis of GC-inducing lesions in HUVEC. GC act on HUVEC, inducing cell damage. Following the event of cell damage, JMY levels upregulate in the nucleus to induce transcription of Bax, triggering apoptosis. JMY can also regulate HUVEC motility via its regulation of VE-cadherin levels.

High failure rate after Beta-tricalcium phosphate grafting for the treatment of femoral head osteonecrosis: a retrospective analysis.

BACKGROUND: Non-vascularized bone grafting is a promising head-preserving technique for younger patients diagnosed as non-traumatic osteonecrosis of the femoral head (NONFH). Among the various types of bone grafting techniques, "light-bulb" procedure grafting with synthetic bone substitute is an attractive option. We aimed to assess the effectiveness of using beta-tricalcium phosphate (ß-TCP) for the treatment of pre-collapse and early post-collapse lesions NONFH. METHODS: From April 2010 to June 2014, 33 patients (47 hips) with NONFH were treated using the afore-mentioned technique. The clinical and radiological outcomes were recorded and compared statistically between pre- and post-operation. Harris hip score (HHS) was used to evaluate the clinical results, and Association Research Circulation Osseous (ARCO) stage was applied to assess the radiological outcomes. RESULTS: The 5-years survival rate of using ß-TCP grafting was accounting for 25.5%. HHS was decreased from 78.47 to 52.87 points, and a very significant worsening of radiological results were revealed (P <  0.05). Two hips collapsed more than 2 mm were awaiting for THA, and 33 of the 47 hips had converted to THAs in an average time to failure of 24.24 months postoperatively. Meanwhile, only 4 hips survived without collapse, and 8 hips collapsed less than 2 mm. After surgery, the time onset of head collapse was 3.65 months on average, and the first conversion to THA was performed at 5 months postoperative. CONCLUSIONS: Our results suggest that "light-bulb" procedure grafting with ß-TCP sticks presented with a high failure rate in the early postoperative period. It is not proposed for the treatment of pre-collapse and early post-collapse lesions NONFH.

Comparison of Total Hip Arthroplasty after Two Types of Failed Hip Preserving Procedures with Primary Total Hip Arthroplasty.

OBJECTIVE: Porous tantalum implantation (PTI) and bone impaction grafting (BIG) through a window at the femoral head neck junction are known as two types of joint-preserving procedures. They provide an alternative option in the treatment of osteonecrosis of the femoral head by providing strong structural support to the subchondral plate. However, when earlier joint-preserving treatments fail, conversion to a total hip arthroplasty seems to be the final treatment of choice. This emphasizes the importance of joint-preserving procedures that do not hinder the clinical results of a subsequent total hip arthroplasty. The results of conversion total hip arthroplasty after failed PTI and BIG are still controversial. The purpose of this study was to compare the clinical and radiological outcomes of total hip arthroplasty after failed PTI or BIG surgery with primary total hip arthroplasty. METHODS: Patients at our institution between 2010 and 2014 who underwent total hip arthroplasty after failed PTI or BIG surgery compared to primary total hip arthroplasty were retrospectively reviewed. A total of 27 patients (30 hips) who underwent total hip arthroplasty after failed PTI surgery (group I) were matched according to age, gender and BMI index with 28 patients (30 hips) who underwent total hip arthroplasty after failed BIG surgery (group II) and 30 patients (30 hips) who underwent primary total hip arthroplasty (group III). The clinical results included preoperative and postoperative Harris Hip score, surgery duration, blood loss volume and clinical complications. Radiological follow-up results included abduction angle and anteversion angle of the acetabular cup, periprosthetic osteolysis, and prosthesis subsidence. RESULTS: There was no significant difference in the preoperative and postoperative Harris Hip score among the three groups at the latest follow-up (P = 0.247). The surgery duration was longer and intra-operative blood loss volume was higher in group I than in group II and group III (P < 0.05, respectively). There was no difference in surgery duration and blood loss volume between group II and group III (P > 0.05). There was no significant difference in radiological follow-up results among the three groups (P > 0.05). Varying degrees of residual tantalum debris were seen on postoperative radiographs of all group I patients. There was no difference in the incidence of complications among the three groups (P > 0.05). CONCLUSIONS: PTI group had higher blood loss volume and surgery duration than BIG group and primary total hip arthroplasty group. BIG group had no significant differences with primary total hip arthroplasty group in clinical and radiological follow-up results. There were no significant differences between the three groups in the Harris Hip score and radiological follow-up results.

Rates of periprosthetic infection and surgical revision in Beijing (China) between 2014 and 2016: a retrospective multicenter cross-sectional study.

BACKGROUND: Periprosthetic joint infection (PJI) is a rare but devastating complication after total joint arthroplasty. There is a paucity of data on the incidence and prevalence of periprosthetic infection in mainland China. This study aimed to analyze the rates of surgical revision after arthroplasty due to PJI and the procedures followed in Beijing, China. METHODS: The study involved a retrospective multicenter cross-sectional survey of patients undergoing revisions for periprosthetic infection after hip/knee arthroplasty at nine hospitals in Beijing from 2014 to 2016. Age, gender, body mass index, primary diagnosis, comorbidity, primary surgery, treatment methods, and post-revision complications were analyzed. RESULTS: A total of 38,319 hip/knee arthroplasties and 366 (0.96%) revisions for PJI were identified. Of these, 161 (161/14,110; 1.14%) revisions involved hip arthroplasty, whereas 205 (205/24,209; 0.85%) revisions were due to knee arthroplasty. Procedures for revisions of infected hip included 7 (4.3%) cases of open debridement and prosthesis retention, 32 (19.9%) cases of one-stage exchange, 121 (75.2%) cases of two-stage exchange, and 1 (0.007%) case of hip dissection. As for the infected knee, the procedures included 45 (22.0%) cases of open debridement and prosthesis retention, 13 (6.3%) cases of one-stage exchange, 143 (69.8%) cases of two-stage exchange, and 4 (0.02%) cases of knee fusion. CONCLUSIONS: The study found the rates of revision due to PJI to be low. Nonetheless, the incidence of PJI in mainland China could be higher and calls for more elaborate studies in geographically and socioeconomically diverse health institutions.

A modified technique for tibial bone sparing in unicompartmental knee arthroplasty.

BACKGROUND: Previously, the authors modified the surgical technique to preserve tibial bone mass for Oxford unicompartmental knee arthroplasty (UKA). The purpose of this study was to determine the clinical outcomes and values of this modified technique. METHODS: Clinical data of 34 consecutive patients who underwent the unilateral modified UKA technique (modified group, 34 knees) were retrospectively analyzed. To compare the outcome, a match-paired control group (conventional group, 34 knees) of an equal number of patients using the conventional technique system in the same period were selected and matched with respect to diagnosis, age, pre-operative range of motion (ROM), and radiological grade of knee arthrosis. Clinical outcomes including knee Hospital for Special Surgery (HSS) score, ROM, and complications were compared between the two groups. Post-operative radiographic assessments included hip-knee-ankle angle (HKA), joint line change, implant position, and alignment. RESULTS: The mean follow-up time was 38.2 ±â€Š6.3 months. There was no difference in baseline between the two groups. The amount of proximal tibial bone cut in the modified group was significantly less than that of the conventional group (4.7 ±â€Š1.1 mm vs. 6.7 ±â€Š1.3 mm, t = 6.45, P < 0.001). Joint line was elevated by 2.1 ±â€Š1.0 mm in the modified group compared with -0.5 ±â€Š1.7 mm in the conventional group (t = -7.46, P < 0.001). No significant differences were observed between the two groups after UKA with respect to HSS score, VAS score, ROM, and HKA. Additionally, the accuracy of the post-operative implant position and alignment was similar in both groups. As for implant size, the tibial implant size in the modified group was larger than that in the conventional group (χ = 4.95, P = 0.035). CONCLUSIONS: The modified technique for tibial bone sparing was comparable with the conventional technique in terms of clinical outcomes and radiographic assessments. It can preserve tibial bone mass and achieve a larger cement surface on the tibial side.

An innovative three-dimensional method for identifying a proper femoral intramedullary entry point in total knee arthroplasty.

BACKGROUND:: Identification of the proper femoral intramedullary (IM) access point is an important determinant of final implant position in IM-guided total knee arthroplasty (TKA). The aim of this study was to identify the optimal entry point in Chinese participants using a new three-dimensional method. METHODS:: A series of computed tomography scans of 44 femurs in Chinese participants from October 2014 to October 2015 were imported into Mimics 17.0 software to identify the optimal entry point. The apex of the intercondylar notch (AIN) was used as the reference bony anatomical landmark to identify the proper entry point to insert the IM rod. The statistical significance was calculated on the basis of a 5% level (P < 0.05) using the Student's t-test. RESULTS:: For the males, the average ideal entry point was 1.49 mm medial and 13.39 mm anterior to the AIN. The values were 1.77 mm medial and 15.29 mm anterior to the AIN in females. A significant difference was present between males and females (13.39 ± 2.46 mm vs. 15.29 ± 3.44 mm, t = 2.124, P = 0.040). When using the recommended location as the entry point for the IM rod, the mean potential error differed significantly from the femoral trochlear groove (the potential error of IM in males in coronal plane: 0.93° ± 0.24° vs. 1.27° ± 0.32°, t = -4.166, P <0.001; the potential error of IM in males in sagittal plane: 1.40° ± 0.42° vs. 2.79° ± 0.70°, t = 7.155, P < 0.001; the potential error of IM in females in coronal plane: 0.73° ± 0.28° vs. 1.15° ± 0.35°, t = 3.940, P < 0.001; and the potential error of IM in females in sagittal plane: 1.48° ± 0.47° vs. 2.76° ± 0.83°, t =5.574, P < 0.001). A significant difference was present between the recommended point and the point 10 mm anterior to the origin of the posterior cruciate ligament (the potential error of IM in males in coronal plane: 0.93° ± 0.24° vs. 1.53° ± 0.43°, t = 5.948, P < 0.001; the potential error of IM in males in sagittal plane: 1.40° ± 0.42° vs. 2.15° ± 0.75°, t = 3.152, P = 0.003; the potential error of IM in females in coronal plane: 0.73° ± 0.28° vs. 1.28° ± 0.42°, t = -4.632, P < 0.001; and the potential error of IM in females in sagittal plane: 1.48° ± 0.47° vs. 2.40° ± 0.93°, t = 3.763, P = 0.001). CONCLUSIONS: The technique described here is an innovative method for swift, easy, and accurate access to the medullary canal during TKA, and it can optimize the position and orientation of the prosthetic components in knee arthroplasty.

Glycosaminoglycan Content of the Lateral Compartment Cartilage in Knees Conforming to the Indications for Oxford Medial Unicompartmental Knee Arthroplasty.

BACKGROUND: The quality of the lateral compartment cartilage is important to preoperative evaluation and prognostic prediction of unicompartmental knee arthroplasty (UKA). Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) enables noninvasive assessment of glycosaminoglycan (GAG) content in cartilage. This study aimed to determine the GAG content of the lateral compartment cartilage in knees scheduled to undergo Oxford medial UKA. METHODS: From December 2016 to May 2017, twenty patients (20 osteoarthritic knees) conforming to the indications for Oxford medial UKA were included as the osteoarthritis (OA) group, and 20 healthy volunteers (20 knees) paired by sex, knee side, age (±3 years), and body mass index (BMI) (±3 kg/m2) were included as the control group. The GAG contents of the weight-bearing femoral cartilage (wbFC), the posterior non-weight-bearing femoral cartilage (pFC), the lateral femoral cartilage (FC), and tibial cartilage (TC) were detected using dGEMRIC. The dGEMRIC indices (T1Gd) were calculated in the middle three consecutive slices of the lateral compartment. Paired t-tests were used to compare the T1Gd in each region of interest between the OA group and control group. RESULTS: The average age and BMI in the two groups were similar. In the OA group, T1Gd of FC and TC was 386.7 ± 50.7 ms and 429.6 ± 59.9 ms, respectively. In the control group, T1Gd of FC and TC was 397.5 ± 52.3 ms and 448.6 ± 62.5 ms, respectively. The respective T1Gd of wbFC and pFC was 380.0 ± 47.8 ms and 391.0 ± 66.3 ms in the OA group and 400.3 ± 51.5 ms and 393.6 ± 57.9 ms in the control group. Although the T1Gd of wbFC and TC tended to be lower in the OA group than the control group, there was no significant difference between groups in the T1Gd in any of the analyzed cartilage regions (P value of wbFC, pFC, FC, and TC was 0.236, 0.857, 0.465, and 0.324, respectively). CONCLUSIONS: The GAG content of the lateral compartment cartilage in knees conforming to indications for Oxford medial UKA is similar with those of age- and BMI-matched participants without OA.

Effects of Lower Limb Alignment and Tibial Component Inclination on the Biomechanics of Lateral Compartment in Unicompartmental Knee Arthroplasty.

BACKGROUND: Lateral compartmental osteoarthritis (LCOA), a major complication after medial mobile-bearing unicompartmental knee arthroplasty (UKA), is highly associated with the increased stress of the lateral compartment. This study aimed to analyze the effects on the stress and load distribution of the lateral compartment induced by lower limb alignment and coronal inclination of the tibial component in UKA through a finite element analysis. METHODS: Eight three-dimensional models were constructed based on a validated model for analyzing the biomechanical effects of implantation parameters on the lateral compartment after medial Oxford UKA: postoperative lower limb alignment of 3° valgus, neutral and 3° varus, and the inclination of tibial components placed in 4°, 2° valgus, square, and 2° and 4° varus. The contact stress of femoral and tibial cartilage and load distribution were calculated for all models. RESULTS: In the 3° valgus lower limb alignment model, the contact stress of femoral (3.38 MPa) and tibial (3.50 MPa) cartilage as well as load percentage (45.78%) was highest compared to any other model, and was increased by 36.75%, 47.70%, and 27.63%, respectively when compared to 3° varus. In the condition of a neutral position, the outcome was comparable for the different tibial tray inclination models. The inclination did not greatly affect the lateral compartmental stress and load distribution. CONCLUSIONS: This study suggested that slightly varus (undercorrection) lower limb alignment might be a way to prevent LCOA in medial mobile-bearing UKA. However, the inclination (4° varus to 4° valgus) of the tibial component in the coronal plane would not be a risk factor for LCOA in neutral position.

Significance of Lateral Pillar in Osteonecrosis of Femoral Head: A Finite Element Analysis.

BACKGROUND: The lateral pillar of the femoral head is an important site for disease development such as osteonecrosis of the femoral head. The femoral head consists of medial, central, and lateral pillars. This study aimed to determine the biomechanical effects of early osteonecrosis in pillars of the femoral head via a finite element (FE) analysis. METHODS: A three-dimensional FE model of the intact hip joint was constructed from the image data of a healthy control. Further, a set of six early osteonecrosis models was developed based on the three-pillar classification. The von Mises stress and surface displacements were calculated for all models. RESULTS: The peak values of von Mises stress in the cortical and cancellous bones of normal model were 6.41 MPa and 0.49 MPa, respectively. In models with necrotic lesions in the cortical and cancellous bones, the von Mises stress and displacement of lateral pillar showed significant variability: the stress of cortical bone decreased from 6.41 MPa to 1.51 MPa (76.0% reduction), while cancellous bone showed an increase from 0.49 MPa to 1.28 MPa (159.0% increase); surface displacements of cortical and cancellous bones increased from 52.4 µm and 52.1 µm to 67.9 µm (29.5%) and 61.9 µm (18.8%), respectively. In addition, osteonecrosis affected not only pillars but also adjacent structures in terms of the von Mises stress and surface displacement levels. CONCLUSIONS: This study suggested that the early-stage necrosis in the femoral head could increase the risk of collapse, especially in lateral pillar. On the other hand, the cortical part of lateral pillar was found to be the main biomechanical support of femoral head.

Local Administration of Bisphosphonate-soaked Hydroxyapatite for the Treatment of Osteonecrosis of the Femoral Head in Rabbit.

BACKGROUND: Systemic administration of bisphosphonates has shown promising results in the treatment of osteonecrosis of the femoral head (ONFH). However, few studies have evaluated the efficacy of local zoledronate (ZOL) administration in the treatment of ONFH. The purpose of this study was to investigate whether local administration of bisphosphonate-soaked hydroxyapatite (HA) could improve bone healing in an experimental rabbit model of ONFH. METHODS: This experimental study was conducted between October 2014 and June 2015. Forty-five rabbits underwent simulated ONFH surgery. Immediately following surgery, they were divided into three groups: model (untreated, n = 15), HA (treated with HA alone, n = 15), and HA + ZOL (treated with HA soaked in a low-dose ZOL solution, n = 15). Histological, immunohistochemical, and quantitative analyses were performed to evaluate bone formation and resorption 2, 4, and 8 weeks after surgery. RESULTS: Gross bone matrix and hematopoietic tissue formation were observed in the HA + ZOL group 4 weeks after surgery. The immunohistochemical staining intensities for 5-bromodeoxyuridine, runt-related transcription factor 2, osteocalcin, osteopontin, and osteoprotegerin were significantly higher in the HA + ZOL group than that in the model (P < 0.001, P< 0.001, P< 0.001, P< 0.001, and P = 0.018, respectively) and HA groups (P = 0.003, P = 0.049, P< 0.001, P = 0.020, and P = 0.019, respectively), whereas receptor activator of the nuclear factor-κB ligand staining intensity was significantly lower in the HA + ZOL group than that in the model and HA groups (P = 0.029 and P = 0.015, respectively) 4 weeks after surgery. No significant differences in bone formation or bone resorption marker expression were found between the three groups 2 or 8 weeks after surgery (P > 0.05). CONCLUSIONS: Local administration of HA soaked in a low-dose ZOL solution increased new bone formation while inhibiting bone resorption in an animal model of ONFH, which might provide new evidence for joint-preserving surgery in the treatment of ONFH.

Finite Element Analysis of Mobile-bearing Unicompartmental Knee Arthroplasty: The Influence of Tibial Component Coronal Alignment.

BACKGROUND: Controversies about the rational positioning of the tibial component in unicompartmental knee arthroplasty (UKA) still exist. Previous finite element (FE) studies were rare, and the results varied. This FE study aimed to analyze the influence of the tibial component coronal alignment on knee biomechanics in mobile-bearing UKA and find a ration range of inclination angles. METHODS: A three-dimensional FE model of the intact knee was constructed from image data of one normal subject. A 1000 N compressive load was applied to the intact knee model for validating. Then a set of eleven UKA FE models was developed with the coronal inclination angles of the tibial tray ranging from 10° valgus to 10° varus. Tibial bone stresses and strains, contact pressures and load distribution in all UKA models were calculated and analyzed under the unified loading and boundary conditions. RESULTS: Load distribution, contact pressures, and contact areas in intact knee model were validated. In UKA models, von Mises stress and compressive strain at proximal medial cortical bone increased significantly as the tibial tray was in valgus inclination >4°, which may increase the risk of residual pain. Compressive strains at tibial keel slot were above the high threshold with varus inclination >4°, which may result in greater risk of component migration. Tibial bone resection corner acted as a strain-raiser regardless of the inclination angles. Compressive strains at the resected surface slightly changed with the varying inclinations and were not supposed to induce bone resorption and component loosening. Contact pressures and load percentage in lateral compartment increased with the more varus inclination, which may lead to osteoarthritis progression. CONCLUSIONS: Static knee biomechanics after UKA can be greatly affected by tibial component coronal alignment. A range from 4° valgus to 4° varus inclination of tibial component can be recommended in mobile-bearing UKA.

Glucocorticoids Significantly Influence the Transcriptome of Bone Microvascular Endothelial Cells of Human Femoral Head.

BACKGROUND: Appropriate expression and regulation of the transcriptome, which mainly comprise of mRNAs and lncRNAs, are important for all biological and cellular processes including the physiological activities of bone microvascular endothelial cells (BMECs). Through an intricate intracellular signaling systems, the transcriptome regulates the pharmacological response of the cells. Although studies have elucidated the impact of glucocorticoids (GCs) cell-specific gene expression signatures, it remains necessary to comprehensively characterize the impact of lncRNAs to transcriptional changes. METHODS: BMECs were divided into two groups. One was treated with GCs and the other left untreated as a paired control. Differential expression was analyzed with GeneSpring software V12.0 (Agilent, Santa Clara, CA, USA) and hierarchical clustering was conducted using Cluster 3.0 software. The Gene Ontology (GO) analysis was performed with Molecular Annotation System provided by CapitalBio Corporation. RESULTS: Our results highlight the involvement of genes implicated in development, differentiation and apoptosis following GC stimulation. Elucidation of differential gene expression emphasizes the importance of regulatory gene networks induced by GCs. We identified 73 up-regulated and 166 down-regulated long noncoding RNAs, the expression of 107 of which significantly correlated with 172 mRNAs induced by hydrocortisone. CONCLUSIONS: Transcriptome analysis of BMECs from human samples was performed to identify specific gene networks induced by GCs. Our results identified complex RNA crosstalk underlying the pathogenesis of steroid-induced necrosis of femoral head.

Minimally invasive unicompartmental knee arthroplasty for spontaneous osteonecrosis of the knee.

OBJECTIVE: To explore the outcome and surgical technique of minimally invasive unicompartmental knee arthroplasty (UKA) for spontaneous osteonecrosis of the knee. METHODS: Twenty-seven patients with medial compartmental spontaneous osteonecrosis treated by minimally invasive Oxford phase 3 UKA from January 2009 to June 2013 were reviewed retrospectively. Twelve subjects were men and 15 women, with an average age of 64.6 ± 8.6 years (52-82 years). At the time of diagnosis, 11 patients had with grade III necrosis and 16 grade IV according to Mont's classification. Pain, range of motion (ROM) and Hospital for Special Surgery (HSS) knee scores were evaluated before and after UKA. Pre-and postoperative alignment of the lower limbs was measured and compared. Postoperative radiographic assessments were made according to the guidelines proposed by the Oxford group at the final follow-up. RESULTS: All patients were followed for a mean time of 27.8 ± 15.9 months (6-59 months). There were no serious adverse events, such as infection, bearing dislocation, aseptic loosening, pulmonary embolism, deep venous thrombosis, cardio-cerebral vascular incident or psychological problems. One revision was required for unrelated causes (fracture of tibia plateau) 3 years after arthroplasty. One femoral component was tilted with a postoperative radiographic angle >10°. One radiolucent line was observed in a patient with spontaneous osteonecrosis of the knee. The two patients with implant failure had no symptoms at last follow-up. Visual analogue scale scores decreased from 6.9 ± 0.9 to 2.0 ± 1.1 (t = 19.27, P = 0.00). Pain was relieved in 96.3% of subjects (26/27). The mean post-operative ROM and femorotibial angle were 125.7° ± 9.6° and 177.7° ± 3.1°, respectively. HSS scores increased from 61.3 ± 9.7 to 93.0 ± 4.8 (t = 14.46, P = 0.00). Of the 27 patients, 26 (96.3%) were satisfied with the outcome of this surgical procedure. CONCLUSION: Minimally invasive UKA is an effective means of managing spontaneous osteonecrosis of the knee. The short-term outcome of UKA is encouraging.

Relationship between preservation of the lateral pillar and collapse of the femoral head in patients with osteonecrosis.

It is difficult to predict if and when the femoral head will collapse and whether the collapse can be minimized. This study examined the final outcome of early-stage osteonecrosis of the femoral head (ONFH) using magnetic resonance imaging to verify the relationship between preservation of the lateral pillar and collapse of the femoral head. A midcoronal section of the femoral head was divided into 3 pillars (medial, central, and lateral) on a T1-weighted image. According to the site of necrosis on the lateral pillar, the necrosis was divided into 3 types: I, the necrosis occupies the central and medial pillars, and the lateral pillar is preserved; II, the necrosis partially occupies the lateral pillar; and III, the necrosis totally occupies the lateral pillar. One group of 87 patients (127 hips) with Association for Research on Osseous Circulation (ARCO) stage I ONFH underwent nonoperative treatment and were followed for 3 to 8 years (average, 6.2 years). Another group of 42 patients (72 hips) with ARCO stage I ONFH underwent debridement and impacted bone graft and were followed for 5 to 9 years (average, 7.1 years). In both groups, the more preserved the lateral pillar, the less collapse occurred. The authors concluded that whether ONFH progressed to collapse is determined by preservation of the lateral pillar. The lateral pillar is the keystone for maintaining the sphere of the femoral head and its preservation.

Quality of sexual life after total hip arthroplasty in male patients with osteonecrosis of femoral head.

BACKGROUND: Patients with osteonecrosis of the femoral head (ONFH) have a severe impact on their health status, functionality and quality of life. Sexual life is an important component of the quality of life and is still a frequently neglected domain in patients with ONFH. The aims of the study were to evaluate the influence of the disease and the total hip arthroplasty (THA) surgery on quality of sexual life (QSL) in these patients. METHODS: A prospective, self-controlled study was done. 247 patients of ONFH who underwent unilateral or bilateral THA were asked to complete a standardized QSL questionnaire, and the score of QSL was evaluated preoperatively and at first year follow-up of post-THA operation. RESULTS: The mean age of the patient was 46.8 (range 25-60) years. 194 cases (78.5%, 276 hips) were alcohol-induced ONFH. There is significant decrease (p = 0.026) in sexual relationship impairment on the 0-8 scale from pre-THA (5.3 ± 0.7) to post-THA (2.3 ± 0.4). There is no significant difference for effect on sexual function (p = 0.14) between pre-THA (2.3 ± 0.4) and post-THA (1.8 ± 0.3). There is significant improvement (p = 0.018) in overall sexual satisfaction degree of patients on the 1-5 scale from pre-THA (2.7 ± 0.2) to post-THA (4.7 ± 0.6), but no significant increase for sexual partner. CONCLUSION: ONFH has impaired relationships with partner and overall sexual satisfaction degree of the male patients; THA has improved significantly relationships with partner and overall sexual satisfaction degree of the male patients, but no effect on sexual function of the patients and overall sexual satisfaction degree of sexual partner.