Lower Activity and Function Scores Are Associated with a Higher Risk of Preoperative Deep Venous Thrombosis in Patients Undergoing Total Hip Arthroplasty

This study was performed to investigate the relationship between patients’ activity and function levels and the incidence of preoperative deep venous thrombosis (DVT) prior to total hip arthroplasty (THA). We retrospectively reviewed 500 patients admitted for primary or revision THA from July 2014 to October 2018. The diagnosis of DVT was confirmed using Doppler ultrasonography 1 month before THA. The patients’ activity and hip function were evaluated using several clinical scores: the Harris Hip Score (HHS), Oxford Hip Score (OHS), University of California Los Angeles (UCLA) activity score, and visual analog scale (VAS) score. Those scores and the medical history were examined for correlations with preoperative DVT using univariate and multivariate models. Univariate regression analysis showed that older age, current steroid use, anticoagulant use, a history of DVT, collagen disease, a lower UCLA activity score, and a lower OHS were associated with an elevated risk of preoperative DVT. The multivariate analyses showed that a higher UCLA activity score (odds ratio (OR): 0.0049–0.012) and higher OHS (OR: 0.0012–0.0088) were associated with a lower risk of preoperative DVT in each model. Age (OR: 1.07 in both models), current steroid use (OR: 9.32–10.45), and a history of DVT (OR: 27.15–74.98) were associated with a higher risk of preoperative DVT in both models. Older age, current steroid use, a history of DVT, a lower UCLA activity score, and a lower OHS were risk factors for preoperative DVT before THA, even when controlling for potential confounders. Patients exhibiting low activity and low function levels were more likely to have DVT, even before surgery.

A novel caged Cookson-type reagent toward a practical vitamin D derivatization method for mass spectrometric analyses

RATIONALE

25-Hydroxylated vitamin D is the best marker for vitamin D (VD). Due to its low ionization efficiency, a Cookson-type reagent, 1,2,4-triazoline-3,5-dione (TAD), is used to improve the detection/quantification of VD metabolites by liquid chromatography/tandem mass spectrometry (LC/MS/MS). However, the high reactivity of TAD makes its solution stability low and inconvenient for practical use. We here describe the development of a novel caged Cookson-type reagent, and we assess its performances in the quantitative and differential detection of four VD metabolites in serum using LC/MS/MS.

METHODS

Caged 4-(4'-dimethylaminophenyl)-1,2,4-triazoline-3,5-dione (DAPTAD) analogues were prepared from 4-(4'-dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione. Their stability and reactivity were examined. The optimized caged DAPTAD (14-(4-(dimethylamino)phenyl)-9-phenyl-9,10-dihydro-9,10-[1,2]epitriazoloanthracene-13,15-dione, DAP-PA) was used for LC/MS/MS analyses of VD metabolites.

RESULTS

The solution stability of DAP-PA in ethyl acetate dramatically improved compared with that of the non-caged one. We measured the thermal retro-Diels-Alder reaction enabling the release of DAPTAD and found that the derivatization reaction was temperature-dependent. We also determined the detection limit and the lower limit of quantifications for four VD metabolites with DAPTAD derivatization.

CONCLUSIONS

DAP-PA was stable enough for mid- to long-term storage in solution. This advantage shall contribute to the detection and quantification of VD in clinical laboratories, and as such to the broader use of clinical mass spectrometry.

Anti-Dengue ED3 Long-Term Immune Response With T-Cell Memory Generated Using Solubility Controlling Peptide Tags

Recombinant proteins are an attractive choice as a safe alternative to traditional live attenuated vaccines. However, most small-size proteins are poorly immunogenic, and adjuvants, whose mode of action remain to be fully clarified, are needed for increasing their immunogenicity. Here, we report the effects of short solubility controlling peptide tags (SCP-tags) on the immunogenicity of DENV3 envelope protein domain 3 (3ED3; 103 residues, 11.46 kDa) in ICR and Swiss albino model mice. The attachment of a 4-Ile SCP-tag (C4I-tag) increased the hydrodynamic radius of 3ED3 from 2.2 ± 0.09 to 111 ± 146 nm as assessed by dynamic light scattering in phosphate buffered saline at 37°C, indicating that the C4I-tag oligomerized 3ED3. Immunization at 30 μg/dose showed that the untagged 3ED3 was not or poorly immunogenic, whereas the C4I-tag increased its immunogenicity by up to 39-fold as assessed by the IgG level measured using ELISA. Moreover, the increased antibody level was sustained for over 6 months after immunization and a high number of effector and central memory T cells were generated. These observations provide solid and quantitative evidence for the hypothesis that subvisible aggregates with hydrodynamic radii of 100 nm can increase immunogenicity and that SCP-tag can establish a long-term, target-specific immune response in a way adequate for the development of a peptide/protein-based DENV vaccine.

Clinical phenotypes based on clinical prognostic factors in patients with secondary hip osteoarthritis: preliminary findings from a prospective cohort study

OBJECTIVES

Recently, several clinical prognostic factors for hip osteoarthritis (OA) progression such as spinal malalignment, reduced spinal mobility, and excessive daily cumulative hip loading have been identified. This study aimed to identify clinical phenotypes based on clinical prognostic factors in patients with secondary hip OA using data from prospective cohort studies and to define the clinical features of each phenotype.

METHODS

Fifty patients participated. Two-step cluster analysis was performed to identify the phenotypes using the following potential prognostic factors for hip OA progression: spinal inclination in standing, thoracolumbar spine mobility, daily cumulative hip moment, and minimum joint space width (JSW) at baseline. Comprehensive basic and clinical features (age, body mass index, hip pain, Harris hip score, JSW, radiographic hip morphology, hip impairments, spinal alignment and mobility, and gait-related variables) and ratio of progressors in 12 months were compared among the phenotypes using bootstrap method (unadjusted and adjusted for age).

RESULTS

Three phenotypes were identified and each phenotype was characterized as follows (P < 0.05): phenotype 1 (30%)-relatively young age and higher daily cumulative hip loading; phenotype 2 (42.0%)-relatively older age, reduced JSW, and less spinal mobility; and phenotype 3 (28.0%)-changed thoracic spine alignment and less spinal (especially in the thoracic spine) mobility. The ratio of progressors among the phenotypes was not statistically significantly different. These characteristics remained after adjustment for age.

CONCLUSION

Three phenotypes with similar progression risk were identified. This finding will help in designing treatment tailored to each phenotype for hip OA progression prevention.Key Points• Three phenotypes with similar progression risk were identified based on clinical prognostic factors.• Phenotype 1 was characterized by young age and higher daily cumulative hip loading.• Phenotype 2 was relatively old age and had reduced JSW and less spinal mobility.• Phenotype 3 had changed thoracic spine alignment and less thoracic spine mobility.

Gait kinematics of the hip, pelvis, and trunk associated with external hip adduction moment in patients with secondary hip osteoarthritis: toward determination of the key point in gait modification

Background

A larger daily cumulative hip loading, which is the product of the external hip adduction moment (HAM) impulse during gait and the number of steps per day has been identified as a factor associated with the progression of secondary hip osteoarthritis (OA). The cause of the increased HAM impulse in patients with hip OA has not been identified. The purpose of this study was to identify the gait parameters associated with HAM impulse during gait in patients with secondary hip OA.

Methods

Fifty-five patients (age 22–65 years) with mild-to-moderate secondary hip OA participated in this cross-sectional study. The HAM impulse during gait was measured using a three-dimensional gait analysis system. To identify the gait parameters associated with HAM impulse, hierarchical multiple regression analysis was performed. The first model (basic model) included body weight and stance phase duration. The second models included gait parameters (gait speed; ground reaction force [GRF] in frontal plane; and hip, pelvic, and trunk angle in frontal plane) and hip pain in addition to the basic model.

Results

Body weight and stance phase duration explained 61% of the variance in HAM impulse. In the second model, which took into account body weight and stance phase duration, hip adduction angle (9.4%), pelvic tilt (6.5%), and trunk lean (3.2%) in addition to GRF explained the variance in the HAM impulse. Whereas larger hip adduction angle and pelvic tilt toward the swing limb were associated with a larger HAM impulse, larger trunk lean toward the stance limb was associated with smaller HAM impulse.

Conclusion

In patients with excessive hip adduction and pelvic tilt toward the swing limb during gait, gait modification may contribute to the reduction of hip joint loading.

Relationship between a Urine Protein-to-creatinine Ratio of 150 mg/gram Creatinine and Dipstick Grade in the Health Checkup: Substantial Number of False-negative Results for Chronic Kidney Disease

OBJECTIVE

Proteinuria is a marker for cardiovascular diseases and all-cause mortality. In the Specific Health Checkups in Japan, when subjects show trace proteinuria (grade±) on dipstick assay, further examination is recommended to them. Although 150 mg/gCr is a threshold for diagnosing chronic kidney disease (CKD), little data on the relationship between dipstick grade± and the protein-creatinine ratio have been reported.

METHODS

A cross-sectional study using urine specimens obtained in a single institute, JCHO Saitama Northern Medical Center, was performed from October 2014 to March 2016. The level of proteinuria was measured in fresh morning urine samples from 819 volunteer participants of the Specific Health Checkups by two methods: Eiken Uropaper III to detect and qualitatively grade proteinuria, and total protein concentration by the pyrogallol red method.

RESULTS

Sensitivity, specificity, and the positive likelihood ratio to detect proteinuria of 30 mg/dL by 1+ were 90.3%, 97.8%, and 41.9, whereas 150 mg/gCr by ± were 45.3%, 81.4%, and 2.4, respectively. Therefore, screening for 150 mg/gCr by dipstick grade± had a false-negative rate of 54.7% and false-negative rate was significantly higher in women (8.0%) than in men (1.7%) (p < 0.0001).

CONCLUSIONS

Although the dipstick assay is useful to detect clinically significant proteinuria, substantial numbers of false-negative results occur in checkups for identifying subjects with a risk of CKD.

Classification of osteonecrosis of the femoral head: Who should have surgery?

Objectives

Using a simple classification method, we aimed to estimate the collapse rate due to osteonecrosis of the femoral head (ONFH) in order to develop treatment guidelines for joint-preserving surgeries.

Methods

We retrospectively analyzed 505 hips from 310 patients (141 men, 169 women; mean age 45.5 years (sd 14.9; 15 to 86)) diagnosed with ONFH and classified them using the Japanese Investigation Committee (JIC) classification. The JIC system includes four visualized types based on the location and size of osteonecrotic lesions on weightbearing surfaces (types A, B, C1, and C2) and the stage of ONFH. The collapse rate due to ONFH was calculated using Kaplan–Meier survival analysis, with radiological collapse/arthroplasty as endpoints.

Results

Bilateral cases accounted for 390 hips, while unilateral cases accounted for 115. According to the JIC types, 21 hips were type A, 34 were type B, 173 were type C1, and 277 were type C2. At initial diagnosis, 238/505 hips (47.0%) had already collapsed. Further, the cumulative survival rate was analyzed in 212 precollapsed hips, and the two-year and five-year collapse rates were found to be 0% and 0%, 7.9% and 7.9%, 23.2% and 36.6%, and 57.8% and 84.8% for types A, B, C1, and C2, respectively.

Conclusion

Type A ONFH needs no further treatment, but precollapse type C2 ONFH warrants immediate treatment with joint-preserving surgery. Considering the high collapse rate, our study results justify the importance of early diagnosis and intervention in asymptomatic patients with type C2 ONFH.

Cite this article: Y. Kuroda, T. Tanaka, T. Miyagawa, T. Kawai, K. Goto, S. Tanaka, S. Matsuda, H. Akiyama. Classification of osteonecrosis of the femoral head: Who should have surgery?. Bone Joint Res 2019;8:451–458. DOI: 10.1302/2046-3758.810.BJR-2019-0022.R1.

Clinical application of injectable growth factor for bone regeneration: a systematic review

Bone regeneration has been the ultimate goal in the field of bone and joint medicine and has been evaluated through various basic research studies to date. Translational research of regenerative medicine has focused on three primary approaches, which are expected to increase in popularity: cell therapy, proteins, and artificial materials. Among these, the local injection of a gelatin hydrogel impregnated with the protein fibroblast growth factor (FGF)-2 is a biomaterial technique that has been developed in Japan. We have previously reported the efficacy of gelatin hydrogel containing injectable FGF-2 for the regenerative treatment of osteonecrosis of the femoral head. Injectable growth factors will probably be developed in the future and gain popularity as a medical approach in various fields as well as orthopedics. Several clinical trials have already been conducted and have focused on this technique, reporting its efficacy and safety. To date, reports of the clinical application of FGF-2 in revascularization for critical limb ischemia, treatment of periodontal disease, early bone union for lower limb fracture and knee osteotomy, and bone regeneration for osteonecrosis of the femoral head have been based on basic research conducted in Japan. In the present report, we present an extensive review of clinical applications using injectable growth factors and discuss the associated efficacy and safety of their administration.

Folding of the Ig-Like Domain of the Dengue Virus Envelope Protein Analyzed by High-Hydrostatic-Pressure NMR at a Residue-Level Resolution

Dengue fever is a mosquito-borne endemic disease in tropical and subtropical regions, causing a significant public health problem in Southeast Asia. Domain III (ED3) of the viral envelope protein contains the two dominant putative epitopes and part of the heparin sulfate receptor binding region that drives the dengue virus (DENV)’s fusion with the host cell. Here, we used high-hydrostatic-pressure nuclear magnetic resonance (HHP-NMR) to obtain residue-specific information on the folding process of domain III from serotype 4 dengue virus (DEN4-ED3), which adopts the classical three-dimensional (3D) ß-sandwich structure known as the Ig-like fold. Interestingly, the folding pathway of DEN4-ED3 shares similarities with that of the Titin I27 module, which also adopts an Ig-like fold, but is functionally unrelated to ED3. For both proteins, the unfolding process starts by the disruption of the N- and C-terminal strands on one edge of the ß-sandwich, yielding a folding intermediate stable over a substantial pressure range (from 600 to 1000 bar). In contrast to this similarity, pressure-jump kinetics indicated that the folding transition state is considerably more hydrated in DEN4-ED3 than in Titin I27.

The use of a bioactive bone cement containing apatite-wollastonite glass-ceramic filler and bisphenol-a-glycidyl methacrylate resin for acetabular fixation in total hip arthroplasty

Aims

In the 1990s, a bioactive bone cement (BABC) containing apatite-wollastonite glass-ceramic (AW-GC) powder and bisphenol-a-glycidyl methacrylate resin was developed at our hospital. In 1996, we used BABC to fix the acetabular component in primary total hip arthroplasty (THA) in 20 patients as part of a clinical trial. The purpose of this study was to investigate the long-term results of primary THA using BABC.

Patients and Methods

A total of 20 patients (three men and 17 women) with a mean age of 57.4 years (40 to 71), a mean body weight of 52.3 kg (39 to 64), and a mean body mass index (BMI) of 23.0 kg/m2 (19.8 to 28.6) were evaluated clinically and radiologically. Survival analyses were undertaken, and wear analyses were carried out using a computer-aided method.

Results

The mean follow-up was 17.6 years (1.5 to 21.1). Radiological loosening occurred in four sockets with aseptic loosening at a mean of 7.8 years (1.5 to 20.7). Kaplan–Meier survival analyses using revision of the acetabular component, radiological loosening of the acetabular component, and the worst-case scenario with revision of the acetabular component to include the two patients lost to follow-up as endpoints yielded survival rates of 94.7%, 84.4%, and 85.0% at ten years, and 70.0%, 84.4%, and 62.8% at 20 years, respectively. Wear analysis revealed a mean linear wear rate of 0.068 mm per year.

Conclusion

The long-term results of primary THAs using BABC were unsatisfactory. Its brittle nature and poor handling properties need to be improved before it becomes an alternative method of fixing the acetabular component in cemented THA. Cite this article: Bone Joint J 2019;101-B:787–792.

Misfolding of a Single Disulfide Bonded Globular Protein into a Low-Solubility Species Conformationally and Biophysically Distinct from the Native One

In practice and despite Anfinsen’s dogma, the refolding of recombinant multiple SS-bonded proteins is famously difficult because misfolded species with non-native SS-bonds appear upon the oxidization of their cysteine residues. On the other hand, single SS-bond proteins are thought to be simple to refold because their cysteines have only one SS-bond partner. Here, we report that dengue 4 envelope protein domain 3 (DEN4 ED3), a single SS-bonded protein can be irreversibly trapped into a misfolded species through the formation of its sole intramolecular SS-bond. The misfolded species had a much lower solubility than the native one at pHs higher than about 7, and circular dichroism measurements clearly indicated that its secondary structure content was different from the native species. Furthermore, the peaks in the Heteronuclear Single Quantum Correlation spectroscopy (HSQC) spectrum of DEN4 ED3 from the supernatant fraction were sharp and well dispersed, reflecting the beta-sheeted native structure, whereas the spectrum of the precipitated fraction showed broad signals clustered near its center suggesting no or little structure and a strong tendency to aggregate. The two species had distinct biophysical properties and could interconvert into each other only by cleaving and reforming the SS-bond, strongly suggesting that they are topologically different. This phenomenon can potentially happen with any single SS-bonded protein, and our observation emphasizes the need for assessing the conformation and biophysical properties of bacterially produced therapeutic proteins in addition to their chemical purities.

Gait- and Posture-Related Factors Associated With Changes in Hip Pain and Physical Function in Patients With Secondary Hip Osteoarthritis: A Prospective Cohort Study

OBJECTIVE

To identify gait- and posture-related factors associated with changes in hip pain and physical function in patients with hip osteoarthritis (OA).

DESIGN

Prospective cohort study.

SETTING

Clinical biomechanics laboratory of a university.

PARTICIPANTS

Consecutive sampling of female patients with mild-to-moderate secondary hip OA (N=30).

MAIN OUTCOME MEASURES

Hip pain (visual analog scale) and physical function (physical component summary of the Medical Outcomes Study 36-Item Short-Form Health Survey) were measured at baseline and 12 months later. With changes in hip pain and physical function as dependent variables, linear regression analyses were performed with gait- and posture-related factors as independent variables with and without adjustment for age, joint space width, and hip pain or physical function at baseline. Posture-related factors included angles of thoracic kyphosis, lumbar lordosis, sacral inclination, spinal inclination, and spinal mobility. Gait-related factors were walking speed, steps per day, joint angles, external hip joint moment impulses, and daily cumulative hip moments.

RESULTS

Multiple linear regression analyses showed that limited hip extension (adjusted standardized B coefficient [95% confidence interval]: -0.52 [-0.88 to -0.17]) and limited external rotation angles (-0.51 [-0.85 to -0.18]) during walking were associated with the worsening of hip pain. An increased thoracic kyphosis (-0.54 [-0.99 to -0.09]), less sacral anterior tilt (0.40 [0.01-0.79]), reduced thoracic spine mobility (0.59 [0.23-0.94]), less steps per day (0.53 [0.13-0.92]), and a slower walking speed (0.45 [0.04-0.86]) were associated with deterioration in physical function.

CONCLUSIONS

Gait- and posture-related factors should be considered when assessing risk and designing preventive interventions for the clinical progression of secondary hip OA.

Dose optimization of topical tranexamic acid for primary total hip arthroplasty: A prospective cohort study

BACKGROUND

Recently, the topical application of tranexamic acid has become widespread, and it is effective in reducing postoperative blood loss and transfusion rate in total hip arthroplasty. There is no consensus on the optimal dose of topical tranexamic acid. This study aimed to assess the efficacy and safety of topical tranexamic acid on postoperative blood loss and determine the optimal topical dose for primary total hip arthroplasty.

METHODS

This prospective cohort study with a robust protocol enrolled 79 patients who received either 1 or 2 g of topical tranexamic acid in 30 mL normal saline solution or an equivalent volume of normal saline at the end of surgery. The primary outcomes were postoperative drain blood loss and hemoglobin decrease on postoperative day 7. The secondary outcomes were transfusion rate, d-dimer level on postoperative day 7, symptomatic deep vein thrombosis rate, and duration of hospital stay.

RESULTS

Both 1 and 2 g tranexamic acid significantly reduced postoperative drain blood loss (p < 0.001). These doses also reduced the hemoglobin concentration decrease on postoperative day 7, but not significantly. Furthermore, 1 and 2 g doses of tranexamic acid had similar effects on postoperative blood loss and hemoglobin concentration decrease. There was no difference in the transfusion rate, d-dimer level, symptomatic deep vein thrombosis rate, and length of hospital stay.

CONCLUSIONS

The use of topical tranexamic acid at the end of surgery is effective and safe for reducing postoperative blood loss in primary total hip arthroplasty. Topical tranexamic acid at a dose of 1 g may be sufficient and cost-effective, with fewer side effects than the higher dose.

Hip-Spine Syndrome: Acetabular Anteversion Angle Is Associated with Anterior Pelvic Tilt and Lumbar Hyperlordosis in Patients with Acetabular Dysplasia: A Retrospective Study

Background:

Hip-spine syndrome was originally described by Offierski and MacNab, who argued that the flexion deformity of the hip rotated the pelvis forward, causing the spine symptoms. We additionally hypothesized that in patients who have osteoarthritis (OA) of the hip, the pelvis is tilted anteriorly to compensate for the anterior acetabular coverage defect. We investigated the hip factors associated with anterior pelvic tilt (PT) in patients who had OA of the hip due to acetabular dysplasia.

Methods:

We retrospectively reviewed the medical records of patients who had undergone total hip arthroplasty between January 2009 and December 2017 to identify those who had unilateral secondary OA due to acetabular dysplasia. Patients who had spinal imbalance, a history of spinal or lower limb fracture or surgery, bilateral OA of the hip, or a severely subluxated hip were excluded, leaving 100 eligible patients. We defined the indicators of an anterior acetabular coverage defect, flexion deformity of the hip, and anterior PT as the acetabular anteversion angle (AAA), extension range of motion (ROM), and anterior tilt of the pelvis, respectively. We measured hip factors and spinal parameters on radiographs and the standardized axial and coronal planes on 3-dimensional computed tomography with reference to the anterior pelvic plane. Hip factors associated with PT were investigated.

Results:

Univariate analysis showed a significant correlation between PT and both AAA (r = –0.389, p < 0.001) and combined anteversion angle (r = –0.272, p = 0.03). Multivariate regression analysis identified AAA (β = –0.385, p < 0.001) and extension ROM (β = 0.212, p = 0.0496) as independent factors associated with PT. Lumbar lordosis and pelvic incidence minus lumbar lordosis were significantly correlated with AAA, but sagittal vertical axis was not.

Conclusions:

When treating patients who have acetabular dysplasia, surgeons should recognize the relationship between the anterior acetabular coverage and anterior PT. Correcting hyperlordosis of the lumbar spine can induce progression of hip OA because it may decrease the acetabular anterior coverage.

Design and assessment of an active anti-epidermal growth factor receptor (EGFR) single chain variable fragment (ScFv) with improved solubility

ScFv is emerging as a therapeutic alternative to the full-length monoclonal antibodies due to its small size and low production cost, but its low solubility remains a limiting factor toward wider use. Here, we increased the solubility of an Anti-epidermal growth factor receptor ScFv (Anti-EGFR ScFv) by attaching, a short 12-residue solubility enhancing peptide (SEP) tag at its C terminus. We first estimated the solubility increase by running 500-ns Brownian dynamics (BD) simulations. We then experimentally evaluated the predictions by producing recombinant Anti-EGFR ScFv with and without a SEP tag (called C9R) in E. coli. At 20 ^°C, ∼85% of Anti-EGFR ScFv-C9R expressed in the soluble fraction, whereas all of the Anti-EGFR ScFv remained in the insoluble fraction. The total yield of Anti-EGFR ScFv-C9R was 17.15 mg which was ∼3 times higher than that of Anti-EGFR ScFv refolded from the insoluble fraction. Static and dynamic light scattering demonstrated the higher solubility of the purified Anti-EGFR ScFv-C9R, and Circular Dichroism (CD) indicated its high thermal stability, whereas the untagged protein aggregated at 37 ^°C and pH 6. Finally, the binding activity of Anti-EGFR ScFv-C9R to EGFR was confirmed by surface plasmon resonance (SPR). Altogether, these results illustrate the improved biophysical and biochemical characteristics of Anti-EGFR ScFv-C9R and emphasize the potentials of SEP-tags for enhancing the solubility of aggregation-prone antibody fragments.

Unexpected dislocation following accurate total hip arthroplasty caused by excessive hip joint laxity during myasthenic crisis: a case report

BACKGROUND

Dislocation following total hip arthroplasty is mainly caused by malposition. However, the coexistence of neuromuscular disorders is also considered a risk for dislocation due to excessive hip joint laxity. To minimize risk of dislocation, preoperative planning using combined anteversion has been widely used. The recommended combined anteversion angle (the total of cup and stem anteversion angles) is 50 ± 10°.

CASE PRESENTATION

A 33-year-old Japanese woman underwent elective total hip arthroplasty due to osteonecrosis of the femoral head associated with corticosteroid pulse therapy for myasthenia gravis. Intraoperatively, no tendency of dislocation was found when simulating an evoking position under general anesthesia. In postoperative X-ray and computed tomography scans, cup inclination, cup anteversion, and stem anteversion angles were 37°, 13°, and 35° respectively. The resulting combined anteversion was 48°, which was set as the target along with accurate placement. Her postoperative course was normal and she was discharged without adverse events. Three months postoperatively, due to worsening of myasthenic weakness in her lower extremities while resting, she tended to raise her left limb up using both hands for sitting up. An anterior dislocation occurred when her legs were in a figure-of-four position. She was brought to an emergency department, and reduction of dislocation was performed. It was inferred that myasthenic crisis in the affected limb enabled excessive passive motion due to joint hyperlaxity. At the end of 2016, elective total hip arthroplasty on the contralateral side was performed. Cup anteversion, stem anteversion, and the combined anteversion angles were 27°, 24°, and 51° respectively. We instructed her to exercise care during passive leg movement, which may worsen her myasthenic condition. She returned to a normal life and was able to walk long distances without a cane. No recurrence of dislocation was seen at final follow-up.

CONCLUSIONS

Even if accurate component orientation is attained in total hip arthroplasty, patients with neuromuscular disorders such as myasthenia gravis have a potential risk of muscle weakness in the affected limb. Therefore, physicians' instructions and patients' careful attention are required to prevent dislocation due to excessive hip joint laxity under conditions of motor weakness.

Patient- and Surgery-Related Factors that Affect Patient-Reported Outcomes after Total Hip Arthroplasty

Patient-reported outcome measures (PROMs) are used to assess satisfaction after total hip arthroplasty (THA); however, the factors that determine these PROMs remain unclear. This study aimed to identify the patient- and surgery-related factors that affect patient satisfaction after THA as indicated by the Oxford Hip Score (OHS). One-hundred-and-twenty patients who underwent primary THA were included. Various patient-related factors, including clinical scores, and surgery-related factors were examined for potential correlations with the OHS at 3, 6, and 12 months post-THA. Univariate regression analysis showed that higher preoperative University of California Los Angeles (UCLA) activity score (p = 0.027) and better preoperative OHS (p = 0.0037) were correlated with better OHS at 3 months post-THA. At 6 months post-THA, the factors associated with better OHS were higher preoperative UCLA activity score (p = 0.039), better preoperative OHS (p = 0.0006), and use of a cemented stem (p = 0.0071). At 12 months post-THA, the factors associated with better OHS were higher preoperative UCLA activity score (p = 0.0075) and better preoperative OHS (p < 0.0001). Multivariate regression analysis showed that the factors significantly correlated with better OHS were female sex (p = 0.011 at 3 months post-THA), osteoarthritis (p = 0.043 at 6 months), higher preoperative OHS (p < 0.001 at 3 and 12 months, p = 0.018 at 6 months), higher preoperative Harris Hip Score (p = 0.001 at 3 months), higher preoperative UCLA activity score (p = 0.0075 at 3 months), and the use of a cemented femoral component (p = 0.012 at 6 months). Patient- and surgery-related factors affecting post-THA PROMs were identified, although the effect of these factors decreased over time.

Bilateral osteonecrosis of the femoral head associated with corticosteroid therapy for alopecia areata: a case report and review of the literature

Corticosteroids have been widely used for the treatment of various inflammatory diseases because they provide an acute response of immunosuppression. Numerous side effects of corticosteroids have also been known, with varying degrees of severity. Osteonecrosis of the femoral head (ONFH) is a rare and serious complication that directly inhibits walking because of femoral head collapse. However, sometimes, clinicians who consider that corticosteroids are required for primary disease do not recognize steroid-induced ONFH. The final stage of ONFH is severe osteoarthritis, requiring total hip arthroplasty. We describe a 23-year-old woman with bilateral ONFH after corticosteroid treatment for alopecia areata (AA). She was administered several intralesional corticosteroid injections to the scalp and repeated systemic corticosteroid therapy for extensive AA. While undergoing therapy, she lost her balance and complained of right groin pain when standing. The patient was subsequently diagnosed with bilateral ONFH. She recovered from AA, but she complained of persistent right hip pain, which subsequently required total hip arthroplasty. We would like to emphasize that patients on corticosteroid therapy for any common disease should be considered as having a potential risk for ONFH. An early stage detection of ONFH is crucial for its treatment. MRI evaluation warrants a higher level of accuracy in early diagnosis of ONFH for the opportunity to undergo joint-preservation surgery in patients with ONFH.