A Nomogram That Characterizes a Patient's Odds of Developing Squeaking After Fourth-generation Ceramic-on-ceramic THA.

BACKGROUND: Although ceramic-on-ceramic (CoC) bearings result in the lowest wear rate of any bearing combination, postoperative squeaking remains worrisome. However, data concerning squeaking in long-term follow-up studies are still lacking, especially for fourth-generation CoC THA. QUESTIONS/PURPOSES: (1) After keeping the prosthesis in place for 10 years, what percentage of patients treated with fourth-generation CoC THA implants report squeaking, and are there points in time when squeaking occurs more frequently? (2) What are the characteristics, association with hip function, and factors associated with squeaking? (3) Can we create a nomogram that characterizes a patient's odds of experiencing squeaking based on the factors associated with it? METHODS: Between January 2009 and December 2011, 1050 patients received primary THAs at our institution, 97% (1017) of whom received fourth-generation CoC THAs because this was the preferred bearing during this period. Of the 1017 eligible patients, 5% (54) underwent THAs performed by low-volume surgeons, 3% (30) were implanted with cemented prostheses, 2% (22) died, 1% (10) were immobile, 1% (six) underwent revision surgery, and 17% (169) were lost to follow-up before 10 years, leaving 726 patients for analysis here at a mean of 11 ± 1 years. In the study cohort, 64% (464) were male and 36% (262) were female, with a mean age of 44 ± 13 years at primary THA. We extracted data about articular noise from follow-up records in our institutional database and used a newly developed questionnaire to ascertain the percentage of patients who reported squeaking at the latest follow-up interval. Although not validated, the questionnaire was modeled on previous studies on this topic. The longitudinal pattern for squeaking was explored to find timepoints when squeaking occurs more frequently. Based on the questionnaire data, we calculated the percentages of frequent, reproducible, and avoidable squeaking. Hip function was evaluated with the Harris Hip Score and WOMAC score and compared between the squeaking and nonsqueaking groups. Factors associated with squeaking, which were examined in a multivariate analysis, were used to develop a nomogram. RESULTS: At 10 years, 16% (116 of 726) of patients reported squeaking. Two squeaking peaks were determined, at 0 to 1 year and 8 to 10 years. Frequent, reproducible, and avoidable squeaking accounted for 42% (36 of 86), 20% (17 of 86), and 41% (35 of 86), respectively. The mean Harris Hip Score (93 ± 4 versus 94 ± 5; p = 0.81) and WOMAC score (16 ± 13 versus 15 ± 13; p = 0.23) did not differ between patients with squeaking and those without. After controlling for potential confounding variables such as etiology and head offset, we found that patients younger than 46 years (odds ratio 2.5 [95% confidence interval 1.5 to 5.0]; p < 0. 001), those who were male (OR 2.0 [95% CI 1.1 to 3.5]; p = 0.04), those having a total flexion and extension arc of less than 50° (OR 2.0 [95% CI 1.2 to 3.3]; p = 0.02), and those with the Corail hip implant (OR 4.1 [95% CI 2.1 to 7.7]; p < 0. 001) were more likely to report squeaking. We created a nomogram that can be used at the point of care that can help clinicians identify patients at a higher risk of experiencing squeaking; this nomogram had good performance (area under the receiver operating characteristic curve of 77%). CONCLUSION: As a potential late complication, squeaking after fourth-generation CoC THA is of concern and may be related to increased stripe wear. We recommend that surgeons use this nomogram to assess the odds of squeaking before selecting a bearing, especially in patients at high risk, to facilitate shared decision-making and improve patient satisfaction. Future external validation of the model is still needed to enhance its applicability.Level of Evidence Level III, therapeutic study.

The 2018 New Definition of Periprosthetic Joint Infection is Valuable for Diagnosis of Persistent Infection at Reimplantation in Patients without Synovial Fluid.

BACKGROUND: Diagnosis of persistent infection at reimplantation of 2-stage exchange revision is a challenging problem. The aim of our study is to evaluate the performance of the 2018 new definition and Musculoskeletal Infection Society (MSIS) criteria in determining the persistent infection at reimplantation in patients without synovial fluid. METHODS: We retrospectively reviewed 150 patients who underwent 2-stage exchange revision from 2014 to 2018. Two models were used to define persistent infection-model 1: identical major criteria of the MSIS criteria and new definition and model 2: identical major criteria of 2 criteria and/or subsequent infection after reimplantation. The predictive accuracy of the new definition and MSIS criteria was compared by using receiver operating characteristic curves. RESULTS: The receiver operating characteristic curves showed that the new definition had good performance in determining the persistent infection, with the area under the curve (AUC) of 0.871 in model 1 and 0.835 in model 2. The optimal threshold for aggregate scores in new definition was 4. The MSIS criteria had limited diagnostic value in both model 1 (AUC = 0.708) and model 2 (AUC = 0.664). In model 1, the sensitivity and specificity were 86.96% and 84.25% in new definition, and 47.83% and 93.70% in MSIS criteria in patients without synovial fluid. In model 2, the sensitivity and specificity were 78.57% and 85.25% in new definition, and 39.29% and 93.44% in MSIS criteria. CONCLUSION: The 2018 new definition of PJI is valuable in the diagnosis of persistent infection, which can improve diagnostic accuracy compared with the MSIS criteria in patients without synovial fluid.

Factors influencing knee valgus alignment in Crowe type IV hip dysplasia after total hip arthroplasty.

BACKGROUND: Valgus deformity of the knee remains a complaint after total hip arthroplasty (THA) among some patients with Crowe type IV hip dysplasia. We aimed to identify the knee alignment in these patients before and after surgery, and to explore the factors contributing to postoperative knee valgus alignment. MATERIALS AND METHODS: We retrospectively reviewed a series of Crowe type IV patients who received THA between February 2010 and May 2019 in our hospital. The patients' medical data were collected from the hospital information system. On both preoperative and postoperative full limb length standing radiographs, the following parameters were measured: hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle, anatomical tibiofemoral angle, anatomical lateral distal femoral angle, femoral neck-shaft angle, pelvic obliquity, limb length, height and lateral distance of hip center, and femoral offset. Univariate and multivariate binary logistic regression were used to identify the factors influencing postoperative knee valgus alignment. RESULTS: A total of 64 Crowe type IV patients (87 hips) were included in the study. Overall, HKA improved from 176.54 ± 3.52° preoperatively to 179.45 ± 4.31° at the last follow-up. Those hips were subdivided into non-valgus group (≥ 177.0°, n = 65) and valgus group (< 177.0°, n = 22) according to postoperative HKA. Only postoperative mLDFA was a significant factor in the multivariate regression model. CONCLUSIONS: The postoperative mLDFA is a major factor related to knee valgus alignment after THA, which combines the preoperative anatomy and surgical reconstruction. Other factors previously published were found to have no significance. LEVEL OF EVIDENCE: III.

Model to Predict Need for Subtrochanteric Shortening Osteotomy During Total Hip Arthroplasty for Crowe Type IV Developmental Dysplasia.

BACKGROUND Indications for subtrochanteric shortening osteotomy (SSOT) during Crowe type IV developmental dysplasia of the hip (DDH) are unclear. The aim of this retrospective study was to create a model to predict the need for performing SSOT. MATERIAL AND METHODS One hundred forty-nine patients (186 hips) with Crowe Type IV DDH who underwent total hip arthroplasty (THA) with S-ROM implants from January 2010 to November 2018 were included in the study. The acetabular components were placed at the true acetabulum and the trial femoral component was inserted. Reduction then was attempted and if it could not be achieved, SSOT was performed. Using multivariable Cox regression analysis, a model was constructed that included age, sex, surgical history, use of a cone- or triangle-shaped sleeve, secondary acetabulum formation, and percentage of dislocation as predictive factors for SSOT. RESULTS SSOTs were performed on 140 of 186 hips. Secondary acetabulum formation was present in 27 hips (58.70%) in which SSOT was not performed 7 (5.00%) in which it was performed. Cone-shaped sleeves were used in 17 hips (36.96%) in which SSOT was not performed versus 15 (10.71%) hips in which it was performed. Dislocation occurred in 31.30±5.80% hips in which SSOT was performed versus 24.05±4.39% of those in which it was not performed. Percentage of dislocation was associated with an increased likelihood of SSOT (odds ratio [OR] 1.24, 95% confidence interval 1.11-1.38), whereas secondary acetabulum formation (OR 0.10, 0.03-0.33) and use of a cone-shaped sleeve (0.18, 0.06-0.53) were associated with decreased likelihood of SSOT. We established a model for prediction of SSOT with a nanogram and the discriminative ability (C statistic) of it was 0.918 (0.79-0.92). CONCLUSIONS Factors that significantly affect likelihood of performing an SSOT were identified and a model with significant ability to predict the need for SSOT in patients with Crowe Type IV DDH was created.

Two-stage exchange Arthroplasty is a viable treatment for Periprosthetic joint infection in inflammatory diseases.

BACKGROUND: Inflammatory diseases are chronic autoimmune systemic autoimmune diseases, which may increase the risk of prosthetic joint infection (PJI) after total joint arthroplasty (TJA). However, to our best knowledge, few studies have studied the association between inflammatory diseases and subsequent failure after two-stage exchange reimplantation. The aims of this study were to identify the differences in (1) serum markers, synovial indicators and pathology results and (2) treatment outcomes following two-stage exchange arthroplasty between patients with or without inflammatory diseases. METHODS: A retrospective review of 184 patients with PJI who underwent two-stage revision from 2014 to 2018 was conducted. PJI was diagnosed by using the MSIS criteria. Serum biomarkers, synovial fluid, organism and pathology results at the time of the PJI diagnosis and reimplantation were compared between patients with or without inflammatory diseases. Treatment success was defined according to the Delphi-based consensus criteria; Kaplan-Meier survivorship curves of the patients were generated and compared. RESULTS: There was no difference in the biomarkers, pathology results or organism profile at the time of the PJI diagnosis. At reimplantation, the patients with inflammatory diseases generally had higher values of serum markers than those without inflammatory diseases. However, synovial white blood cell count was comparable in patients with inflammatory diseases (1142.8 ± 1385.3*109/mL) and group C (1315.8 ± 1849.3*109/mL, p = 0.841). The total treatment success rate was 91.3% (92% for individuals with inflammatory diseases and 91.2% for the controls). The survivorship of the inflammatory disease group was comparable with that of the control group. CONCLUSION: Two-stage exchange arthroplasty is a viable option for PJIs with inflammatory diseases. Synovial fluid analysis may be less affected by inflammatory diseases than serum markers did in the diagnosis persistent infection at reimplantation.

Association between the LIPG polymorphisms and serum lipid levels in the Maonan and Han populations.

INTRODUCTION: The Maonan population is a relatively isolated minority in China. Little is known about endothelial lipase gene (LIPG) single nucleotide polymorphisms (SNPs) and serum lipid levels in the Chinese populations. The present study aimed to detect the association of several LIPG SNPs and environmental factors with serum lipid levels in the Chinese Maonan and Han populations. METHODS: In total, 773 subjects of Maonan ethnicity and 710 participants of Han ethnicity were randomly selected from our previous stratified randomized samples. Genotypes of the LIPG rs2156552, rs4939883 and rs7241918 SNPs were determined by polymerase chain reaction-restriction fragment length polymorphism, and then confirmed by direct sequencing. RESULTS: The allelic (rs2156552, rs4939883 and rs7241918) and genotypic (rs2156552 and rs4939883) frequencies were different between the two ethnic groups (p < 0.05-0.01). The minor allele carriers had lower apolipoprotein (Apo)A1/ApoB ratio (rs2156552 and rs7241918), high-density lipoprotein cholesterol (HDL-C) and apolipoprotein (Apo)A1 (rs2156552) levels and higher ApoB levels (rs4939883) in the Han population, and lower HDL-C (rs2156552, rs4939883 and rs7241918) levels in the Maonan minority than the minor allele non-carriers (p < 0.0167 after Bonferroni correction). Subgroup analyses according to sex showed that the minor allele carriers had a lower ApoA1/ApoB ratio (rs2156552 and rs7241918) and higher ApoB levels (rs7241918) in Han males, and lower ApoA1 and HDL-C levels in Maonan females than the minor allele non-carriers (p < 0.0167-0.001). CONCLUSIONS: The present study demonstrates the association between the LIPG polymorphsims and serum lipid levels in the two ethnic groups. These associations might have an ethnic- and or/sex-specificity.

LIPG SNPs, their haplotypes and gene-environment interactions on serum lipid levels.

BACKGROUND: Maonan nationality is a relatively conservative and isolated minority in the Southwest of China. Little is known about the association of endothelial lipase gene (LIPG) single nucleotide polymorphisms (SNPs) and serum lipid levels in the Chinese populations. METHODS: A total of 1280 subjects of Maonan nationality and 1218 participants of Han nationality were randomly selected from our previous stratified randomized samples. Genotypes of the four LIPG SNPs were determined by polymerase chain reaction-restriction fragment length polymorphism, and then confirmed by direct sequencing. RESULTS: Several SNPs were associated with high-density lipoprotein cholesterol (rs3813082, rs2000813 and rs2097055) in the both ethnic groups; total cholesterol and apolipoprotein (Apo) A1 (rs2000813) in Han nationality; and low-density lipoprotein cholesterol, ApoB, triglyceride (rs2097055) and ApoA1 (rs3819166) in Maonan minority (P < 0.0125 for all after Bonferroni correction). The commonest haplotype was rs3813082T-rs2000813C-rs2097055T-rs3819166A (Han, 44.2% and Maonan, 48.7%). The frequencies of the T-C-T-A, T-C-T-G, T-T-C-G and G-T-C-G haplotypes were different between the Maonan and Han populations (P < 0.05-0.001). The associations between haplotypes and dyslipidemia were also different in the Han and/or Maonan populations (P < 0.05-0.001). CONCLUSIONS: The differences in serum lipid profiles between the two ethnic groups might partly be attributed to these LIPG SNPs, their haplotypes and gene-environmental interactions. TRIAL REGISTRATION: Retrospectively registered.

Centrifugation May Change the Results of Leukocyte Esterase Strip Testing in the Diagnosis of Periprosthetic Joint Infection.

BACKGROUND: Centrifugation is used to remove the color interference by erythrocytes in blood-synovial fluid samples before leukocyte esterase (LE) strip testing. However, the impact of centrifugation requires further study. METHODS: From April 2016 to October 2017, 133 (53 infected and 80 noninfected) patients were included in this study. One drop of synovial fluid was applied to LE strips before and after centrifugation in 110 cases. The other 23 cases could not be read without centrifugation due to the color disturbance caused by blood contamination. The results were recorded after approximately 3 minutes according to different color grades on a color chart, including grade 3 (++), grade 2 (+), and grade 1 (others). RESULTS: After centrifugation, almost every sample was lighter in color than before. Although most results changed inconspicuously and remained in the same grade, 18.6% (8/43) and 17.9% (12/67) of cases were downgraded in the periprosthetic joint infection and non-periprosthetic joint infection groups, respectively. Before centrifugation, when grade 3 (++) was used as the positive threshold, the sensitivity and specificity were 97.7% (86.2%-99.9%) and 100% (94.3%-100%), respectively. After centrifugation, when grades 2 and 3 (+ and ++, respectively) were used as the positive threshold, the sensitivity and specificity were 92.5% (80.9%-97.6%) and 100% (94.3%-100%), respectively. CONCLUSIONS: The influence of centrifugation should be considered when interpreting the LE strip test results. For cases without centrifugation, we recommended using ++ as the positive threshold, while for cases using centrifugation, the threshold should be reduced to both ++ and +.

Management of severe femoral bone defect in revision total hip arthroplasty--a 236 hip, 6-14-year follow-up study.

This study evaluated the clinical effect of impaction bone graft and distal press-fit fixation for the reconstruction of severe femoral bone defect in revision total hip arthroplasty. A total of 234 patients (involving 236 hips) with Paprosky III and IV femoral bone defects were treated with the revision total hip arthroplasty from June 1998 to Aug. 2006. Impaction bone graft technique was used for 112 hips, with allogeneic freeze-dried bone as bone graft and SPII as prosthesis. With 124 hips, modular distal press-fit fixation and tapered femoral stem (MP stem) were employed. After the operation, the subjects were followed up on regular basis and results were assessed by using the Harris Hip Score (HHS) and 12-item Short Form Health Survey (SF-12). Radiolucence, subsidence and loosening were observed and complications, including infection, fracture, dislocation etc. were recorded. A 6-14-year follow-up showed that prostheses failed, due to infection, in 4 patients of impaction bone graft group and that 6 patients in the press-fit fixation group experienced prosthesis failure, with the survival rates for the two techniques being 96.43% and 95.16%, respectively. One-way ANOVA showed that prosthesis survival was significantly associated with surgery-related complications (P<0.05) and was not related to the type of the bone defects (P>0.05). The rate of complications bore significant association with the type of bone defects in the two groups (P<0.05). Our study showed that the two revision methods could achieve satisfactory mid-term and long-term results for the reconstruction of severe bone defects. It is of great significance for attaining high prosthesis survival rate to select suitable operation on the basis of the type of bone defect. Careful operative manipulation and post-operative rehabilitation aimed at reducing complications are also important.

[Effects of three different treatments on atherosclerosis and adipose in rats].

OBJECTIVE: To explore the effects of three different treatments, including probucol plus aspirin (PS), lovastatin plus aspirin (AS) and probucol, lovastatin plus aspirin (PAS) on atherosclerotic plaque and adipose. METHODS: A total of 31 SD rats with established atherosclerosis were randomly divided into control group (n = 7), high-fat group (n = 4), PS group (n = 8), AS group (n = 5) and PAS group (n = 7). The PS group rats were lavaged with probucol (104.4 mg×kg(-1)×d(-1)) and aspirin 10.4 mg×kg(-1)×d(-1)), AS group ones aspirin (10.4 mg×kg(-1)×d(-1)) and lovastatin (2.1 mg×kg(-1)×d(-1)) and PAS group ones probucol (104.4 mg×kg(-1)×d(-1)), aspirin (10.4 mg×kg(-1)×d(-1)) and lovastatin (2.1 mg×kg(-1)×d(-1)) for 8 weeks. At the same time, the control group received an equal volume of saline. Finally the plaque stability and adipose function of treatment groups were evaluated by the changes of body weight, serum parameters, adipose weights and pathological specimens. RESULTS: Body weights in PS and PAS groups significantly increased than those in AS group (251 g ± 5 g and 247 g ± 7 g vs 220 g ± 6 g, P < 0.01). The serum levels of low density lipoprotein cholesterol (LDL), glucose (Glu), total cholesterol (TC) and high density lipoprotein cholesterol (HDL) were significantly better in PS and PAS groups than those in AS group (P < 0.01). The level of tumor necrosis factor-alpha (TNF-α) was lower in PAS group than that in high-fat group (27 ± 21 vs 100 ± 34 pg/ml, P < 0.05). The stability level of atherosclerotic plaque was more in PAS group than those in PS and AS groups by oil red staining in aorta, oil red staining in different organs and hematoxylin and eosin staining in different aortal parts. CONCLUSION: Atherosclerosis improves more pronouncedly in PS and PAS groups than that in AS group. Through an analysis of the changes of fat-related indicators, adipose factor may play an important role in atherosclerotic treatment.

[The role of large femoral head components in revision of total hip arthroplasty].

OBJECTIVE: To study the efficiency of decreasing instability of large femoral head components in revision total hip arthroplasty (THA). METHODS: From August 2005 to December 2010, 107 patients (112 hips) with 28 mm femoral head components (28 mm group) and 46 patients (46 hips) with 36 mm femoral head components (36 mm group) in revision THA were analyzed retrospectively in order to find if the dislocation rate and Harris hip score were different between the two groups at the time of last follow-up. All the operations were performed by the first author. There were 81 male patients (85 hips) and 26 female patients (27 hips) in 28 mm group with mean age of (62±17) years (26-79 years) and 33 male patients (33 hips) and 13 female patients (13 hips) in 36 mm group with mean age of (60±16) years (31-77 years). RESULTS: The mean follow-up period was 43.3 months (33-71 months) for 28 mm group and 26.7 months (12-37 months) for 36 mm group. There were 7 patients dislocated after revision in 28 mm group, including 2 revised with reinforcement rings (with dislocation rate 9.5%), 3 revised with impaction bone grafting technique (with dislocation rate 8.3%) and 2 revised with cementless cups (with a dislocation rate 3.6%). The dislocation rate of this group was 6.2%. While the dislocation rate of 36 mm group was 2.2%, the only dislocated patient was because of loss of gluteus medius muscle function in the index operation. If this case was excluded, the dislocation rate of 36 mm group would be 0. There was significant difference between the two groups (χ2=103.0095, P<0.01). The Harris hip score was 88±11 for 28 mm group and 89±9 for 36 mm group, there was no significant difference between the two groups (P>0.05). CONCLUSION: The large femoral head components can significantly decrease the instability after revision THA, which should be used in revision THA.

[Clinical effect of Corail femoral prosthesis with different offset in total hip arthroplasty].

OBJECTIVE: To explore the early clinical efficacy of primary total hip arthroplasty(THA) with Corail standard stems (KS type) and high offset stems (KHO type), by analyzing the postoperative radiographic parameters of different offset of femoral components with Corail stem which has a neck-shaft angle of 135 ° in unilateral primary THA, by comparing the measurement results on both sides and analyzing the reconstruction of the postoperative femoral offset and the hip joint function recovery. METHODS: A retrospective analysis was made of 186 patients with unilateral hip joint lesions who underwent the first total hip arthroplasty with Johnson & Johnson Corail prostheses from January 2015 to June 2017. According to the use of femoral prostheses with different eccentricities during the operation, the patients were divided into high eccentricity group and standard eccentricity group. In the high eccentricity group, there were 52 cases of Corail high eccentricity prosthesis(KHO type), including 20 females and 32 males;aged 21 to 71 years old with an average of(50.6±13.2) years;body mass index(BMI) was (26.0±4.1) kg/m2. The standard eccentricity group included 134 Corail standard femoral stem prostheses(KS type), 57 females and 77 males;aged 18 to 77 years old with an average of (47.3±14.0) years;BMI was (25.3±3.5) kg/m2. The abduction arm, femoral eccentricity, acetabular eccentricity and the length difference of lower limbs were measured on the postoperatively positive X-ray film of the hip joint. Harris score and related complications were recorded before and after the operation, and the stability of the prosthesis was analyzed. RESULTS: There were significant differences in femoral eccentricity, joint eccentricity and abduction arm between the affected side and the healthy side in the high eccentricity group(P<0.05). There were significant differences in femoral eccentricity and acetabular eccentricity between the affected side and the healthy side in the standard eccentricity group(P<0.05). There were significant differences in combined eccentricity, abduction arm and length of lower limbs between two groups(P<0.05). In the high eccentricity group, the abduction arm of the affected hip joint was positively correlated with the femoral eccentricity, acetabular eccentricity and joint eccentricity(r=0.633, P<0.001;r=0.384, P=0.005;r=0.690, P<0.001). The same results were also obtained in the healthy side(r=0.688, P<0.001;r=0.574, P<0.001;r=0.765, P<0.001). In the standard eccentricity group, the abduction arm of the affected hip joint was positively correlated with the femoral eccentricity, acetabular eccentricity and combined eccentricity(r=0.734, P<0.001;r=0.418, P<0.001;r=0.749, P<0.001). The same results were also obtained in the healthy side(r=0.775, P<0.001;r=0.397, P<0.001;r=0.773, P<0.001). The difference of the length of both lower limbs was significantly correlated with the difference of bilateral joint eccentricity and bilateral abduction arm (r=0.376, P=0.006;r=-0.346, P=0.012). There was no significant correlation between the difference of the length of both lower limbs and the difference of bilateral joint eccentricity and bilateral abduction arm (r=-0.009, P=0.919;r=-0.036, P=0.682). There was no significant difference in Harris score between two groups at the last follow-up(P>0.05). At the last follow-up, Trendelenburg was negative in all patients in both groups, and the prostheses were stable. CONCLUSION: Both Corail standard stem and high offset stem may be effectively reconstruct the femoral offset, reconstruct the anatomical structure and biomechanics of the hip joint, and maintain the length of lower limbs and the stability of the hip joint in the unilateral primary total hip arthroplasty. Although the offset of the femur was not reconstructed normally in some cases, the stability of the components and postoperative function were not affected.

Gender Differences in Ankylosing Spondylitis Patients with Advanced Hip Involvement: Results from A Matched Retrospective Cohort Study.

OBJECTIVE: To determine the gender differences in ankylosing spondylitis (AS) patients with advanced hip involvement. METHODS: We retrospectively analyzed the 373 consecutive AS patients with advanced hip involvement from 2012 to 2017 and divided them into two groups by sex with 340 men and 33 women. Research data on hip involvement in the patients were obtained from medical records and radiographs. The severity of radiographic hip involvement was evaluated by the Bath Ankylosing Spondylitis Radiology Hip Index (BASRI-hip) scoring system. The data on clinical characteristics, radiographic hip involvement, and laboratory values were compared between the two groups. The comparison was performed again between the two groups after adjusting for the onset age and disease duration by propensity score matching (PSM). RESULTS: Men underwent total hip arthroplasty earlier than women in the patients, with a median age of 31 years (range, 19-67 years) vs 36 years (range, 23-67 years), respectively (P < 0.05). Hip involvement was found to be younger in men than that in women, with a median age of 18 years (range, 7-56 years) vs 23 years (range, 5-55 years) (P < 0.05), and men with bilateral onset in hips had a higher frequency than women with that (66.2% vs 39.4%) (P < 0.05). There was no gender difference in the proportion of bilateral advanced hip involvement (85.3% vs 72.7%) (P > 0.05). The proportion of the patients who had spinal involvement (89.1% vs 69.7%), flexion contracture in the hip (43.8% vs 24.2%), hip range of motion =0° (53.5% vs 30.3%), and an elevated level of C-reactive protein (CRP) (69.1% vs 51.5%) was significantly higher in men than that in women (P < 0.05). After adjusting for the onset age and disease duration by PSM (1:1), men with bilateral onset in hips still had a higher frequency than women with that (76.7% vs 40.0%), and the proportion of the patients who had spinal involvement (90.0% vs 66.7%) and an elevated level of CRP (80.0% vs 53.3%) was significantly higher in men than that in women (P < 0.05). CONCLUSIONS: The disease pattern of hip involvement in AS has gender differences, with bilateral onset being the dominant pattern in men and unilateral onset being more common in women. However, the frequency of bilateral advanced hip involvement has no gender difference eventually. The higher prevalence of spinal involvement in men with AS may be responsible for the more severe functional impairment compared with women.

Different squatting positions after total knee arthroplasty: A retrospective study.

BACKGROUND: Total knee arthroplasty (TKA) has been shown to improve quality of life and reduce pain. High-flexion activities such as squatting, kneeling, and floor transfers are mainly listed as demanding tasks. Among them, squatting is an important position. AIM: To provide a new squat position classification and evaluate the different squatting positions of a series of patients after primary TKA. METHODS: From May 2018 to October 2019, we retrospectively reviewed 154 video recordings of the squatting-related motions of patients after TKA. Among the included patients, 119 were women and 35 were men. Their mean age at the index surgery was 61.4 years (range, 30 to 77). RESULTS: The median follow-up was 12 mo (range, 6 to 156 mo). We classified those squatting-related motions into three major variations according to squatting depth: Half squat, parallel squat, and deep squat. The angles of hip flexion, knee flexion, and ankle dorsiflexion were measured in the screenshots captured from the videos at the moment of squatting nadir. A total of 26 patients were classified as half squats, 75 as parallel squats, and 53 as deep squats. The angles of hip flexion, knee flexion, and ankle dorsiflexion all differed significantly among the three squatting positions (P < 0.001). In the parallel squat group, the mean knee flexion angle (°) was 116.5 (SD, 8.1; range, 97 to 137). In the deep squat group, the mean knee flexion angle (°) was 132.5 (SD, 9.3; range, 116 to 158). CONCLUSION: Among the three squatting positions, deep squat showed the highest hip, knee, and ankle flexion angles, followed by the parallel squat. With the improvement of squatting ability, the patient's postoperative satisfaction rate was also significantly enhanced. However, the different squatting abilities of the patients cannot be effectively distinguished from the scoring results (P > 0.05). Our squatting position classification offers a pragmatic approach to evaluating patients' squatting ability after TKA.

Early patellar tendon rupture after total knee arthroplasty: A direct repair method.

BACKGROUND: Patellar tendon rupture after total knee arthroplasty (TKA) is a catastrophic complication. Although the occurrence of this injury is rare, it can lead to significant dysfunction for the patient and is very tricky to deal with. There has been no standard treatment for early patella tendon rupture after TKA, and long-term follow-up data are lacking. AIM: To introduce a direct repair method for early patella tendon rupture following TKA and determine the clinical outcomes and complications of this method. METHODS: During the period of 2008 to 2021, 3265 consecutive TKAs were retrospectively reviewed. Twelve patients developed early patellar tendon rupture postoperatively and were treated by a direct repair method. Mean follow-up was 5.7 years. Demographic, operative, and clinical data were collected. The clinical outcomes were assessed using the Western Ontario and McMaster Universities (WOMAC) score, the Hospital for Special Surgery (HSS) score, knee range of motion, extensor lag, and surgical complications. Descriptive statistics and paired t test were employed to analyze the data. RESULTS: For all 12 patients who underwent direct repair for early patellar tendon rupture, 3 patients failed: One (8.3%) for infection and two (17.6%) for re-fracture. The two patients with re-fracture both underwent reoperation to reconstruct the extensor mechanism and the patient with infection underwent revision surgery. The range of motion was 109.2° ± 10.6° preoperatively to 87.9° ± 11° postoperatively, mean extensor lag was 21° at follow-up, and mean WOMAC and HSS scores were 65.8 ± 30.9 and 60.3 ± 21.7 points, respectively. CONCLUSION: This direct repair method of early patellar tendon rupture is not an ideal therapy. It is actually ineffective for the recovery of knee joint function in patients, and is still associated with severe knee extension lag and high complication rates. Compared with the outcomes of other repair methods mentioned in the literature, this direct repair method shows poor clinical outcomes.

[Application of high offset Corail femoral stem prosthesis in unilateral primary total hip arthroplasty].

OBJECTIVE: To investigate the application of high offset femoral stem prosthesis in primary total hip arthroplasty. METHODS: From January 2015 to June 2017, 51 patients with unilateral hip diseases who underwent primary total hip arthroplasty with Corail high offset femoral stem prosthesis(KHO type) were selected for retrospective study, including 20 females and 31 males;the age ranged from 21 to 71 years old with an average of(50.8±13.3) years old. The abduction arm, femoral offset, acetabular offset and the length of lower limbs were measured on the positive X-ray film of hip joint after operation. Harris scores before and after operation and related complications were recorded, and the stability of prosthesis was analyzed. RESULTS: The femoral offset, combined offset and abduction arm of the affected side were significantly greater than those of the healthy side(P<0.05). There was no significant difference in acetabular offset between the affected side and the healthy side (P>0.05). The femoral offset of 17 hips (33.3%) was reconstructed normally, of which 15 cases (88.2%) had equal length of both lower limbs. The femoral offset of 34 hips (66.7%) was greater than that of the healthy side, and 34 cases (100%) had equal length of both lower limbs. All 51 patients were followed up for(42.3±7.3) months. The Harris score increased from 38.0±7.6 before operation to 92.1±3.1 at the final follow-up(P<0.001). CONCLUSION: Although the high offset Corail prosthesis can not normally reconstruct the femoral offset in unilateral primary total hip arthroplasty, it does not affect the reconstruction of the length of lower limbs and the stability of the prosthesis.

Preparation, release profiles and antibacterial properties of vancomycin-loaded Ca-P coating titanium alloy plate.

The aim of the study was to explore the feasibility of the Ca-P coating titanium alloy plate to be used as the vancomycin drug-delivery system by biomimetic coating technology. Through the X-ray diffraction study, the main components of the coatings were identified as octocalcium phosphate. The in vitro vancomycin release, bacteriostasis activity to Staphylococcus aureus (S. aureus), the scanning electron microscope (SEM) image and osteoblast adhesion and proliferation test of vancomycin-loaded Ca-P coating plate were evaluated. The bacteriostatic activity of the vancomycin-loaded Ca-P coating plate showed a continuous drug release and had an inhibitory effect on the growth of the S. aureus. In vitro osteoblast culture results showed that the Ca-P coating plate loaded with or without the vancomycin both obviously promoted the osteoblast attachment. It was suggested that the vancomycin-loaded Ca-P coating may be compounded in the surface of the internal fixators to reduce the incidence of the implant-associated infection.

[Microbiological analysis of late infected hip arthroplasty in 62 cases].

OBJECTIVE: To review the type and number of pathogens and their antibiotic sensitivity in patients with late infected total joint replacement so as to offer guidance for the choice of antibiotics. METHODS: A retrospective analysis was conducted for 62 patients whose suspected specimens were obtained intra-operatively during a total hip arthroplasty since January 2002 to August 2010 at our department. Their demographic data, bacterial species and antibiotic sensitivity profiles were recorded. RESULTS: Among 62 cases, the cultures were tested positive in 48 cases; the most common bacteria was Gram-positive bacteria (74%). And coagulase-negative staphylococci and Staphylococcus aureus accounted for 62.9% of all bacterial cultures. And the ratio of methicillin-resistant Staphylococcus was 41.18%. CONCLUSION: The late infection of total hip arthroplasty is mainly caused by Gram-positive bacteria. Antibiotic treatment for late periprosthetic infection should be guided by the findings of drug susceptibility. Vancomycin may be used as a primary agent for the treatment of infected hip arthroplasty.

[Application of individualized setting of femoral opening point and valgus angle in artificial total knee arthroplasty for patients with external femoral arch].

OBJECTIVE: To investigate whether shifting the femoral opening point and setting a personalized femoral valgus angle can improve the lower limb force line of total knee arthroplasty (TKA) patients with external femoral arch. METHODS: From March 2016 to October 2018, 50 patients (55 knees) with osteoarthritis with genu varus deformity combined with external femoral arch for TKA were selected. There were 10 males and 40 females. The age ranged from 63.1 to 80.5 years old, with an average of (67.8±5.8) years old. Forty-five cases were unilateral and 5 cases were bilateral. The osteoarthritis stages of 55 knees were Kellgren-Lawrence grade Ⅲ to Ⅳ; and the course of disease ranged from 2 to 10 years. PreoperativeSpecial Surgery (Hospital for Special Surgery) scores:pain was 15.20±3.52; function was 8.30±2.96;mobility was 10.15±2.85;muscle strength was 4.20±1.95;flexion deformity was 5.50±3.05;stability was 6.15±2.20; total score was 47.93±3.39. The external femoral arch angle ranged from 6.4° to 16.7°, with a mean of (10.63±2.29) °. The tibiofemoral angle ranged from 7.4° to 12.6°, with a mean of (12.04±3.59)°. The anatomical distal femoral angle ranged from 83.10° to 91.20°, with a mean of (84.55± 1.66)°. And the distance from the center of the knee joint to the lower limb line of force ranged from 2.01 to 6.00 cm, with a mean of (3.57±1.12) cm. During the replacement surgery, the femoral opening point and the valgus angle were individually set to obtain a good line of force of the lower limbs. RESULTS: Before the operation, the distance of femoral opening point ranged from 0.24 to 0.74 cm, with a mean of (0.54±0.10) cm. The distance between the internal and external condyles of the femur ranged from 6.86 to 8.12 cm, with a mean of (7.27±0.27) cm. The preoperative valgus correction angle (VCA) ranged from 7.20° to 13.80°, with a mean of (9.38±1.38) °. The post-correction valgus correction angle' (VCA') ranged from 6.10° to 9.50°, with a mean of (7.36±0.82) °. All patients were followed up, and the duration ranged from 3 to 36 months, with an average of (13.5±5.8) months. All patients obtained good knee function after operation. Three months after operation, HSS scores included pain of 25.30±3.05, function of 18.25±2.05, mobility of 16.05±0.75, muscle strength of 6.20±2.10, flexion deformity of 8.80±1.85, stability of 8.20±1.75; and the total score ranged from 90.00 to 93.00, with an average of 91.82±0.98. The total score was higher than that before operation (t=1.728, P=0.038). Postoperative X-ray examination showed that there were no signs of loosening, sinking, or osteolysis of the prosthesis. The tibiofemoral angle on the weight-bearing X-ray on the second day after surgery ranged from 1.30° to 4.90°, with a mean of (2.53±0.83) °;the angle ranged from 87.50° to 91.30°, with a mean of (88.73±0.86) °;and the distance from the center of the knee joint to the lower limb line of force ranged from 0.02 cm to 1.20 cm, with a mean of (0.23±0.05) cm; which were improved compared with those before operation (t=2.415, P=0.019;t=1.496, P=0.041;t=1.912, P=0.033). CONCLUSION: In TKA combined with external femoral arch, good lower limb force line and knee joint function can be obtained by externally shifting the femoral opening point and setting a personalized femoral valgus angle.

The relationship of C-reactive protein/interleukin-6 concentrations between serum and synovial fluid in the diagnosis of periprosthetic joint infection.

BACKGROUND: The relationship of C-reactive protein (CRP)/interleukin-6 (IL-6) concentrations between serum and synovial fluid and whether synovial CRP/IL-6 testing in addition to serum CRP/IL-6 testing would result in a benefit in the diagnosis of periprosthetic joint infection (PJI) deserves to be investigated. METHODS: From June 2016 to July 2019, 139 patients were included in the study. Synovial CRP and IL-6 were tested by ELISA. The serum CRP and IL-6 were obtained from medical records. The definition of PJI was based on the modified Musculoskeletal Infection Society (MSIS) criteria. The relationship of serum and synovial CRP and IL-6 and the value of each index in the diagnosis of PJI were evaluated. RESULTS: The receiver operating characteristic (ROC) curves showed that synovial IL-6 had the highest area under the curve (AUC) at 0.935, which was followed by synovial CRP, serum IL-6 and serum CRP 0.861, 0.847 and 0.821, respectively. When combining serum CRP and synovial CRP to diagnose PJI, the AUC was 0.849, which was slightly higher than the result obtained when using serum CRP alone. In contrast, when combining serum IL-6 and synovial IL-6 to diagnose PJI, the AUC increased to 0.940, which was significantly higher than that obtained using serum IL-6 alone. CONCLUSION: The synovial IL-6 has the highest diagnostic accuracy for PJI. However, inferring the level of CRP/IL-6 in the synovial fluid from the serum level of CRP/IL-6 was not feasible. Synovial CRP testing did not offer an advantage when combined with an existing serum CRP result to diagnose PJI, while additional synovial IL-6 was worthy of testing even if there was an existing serum IL-6 result.