Clinical three-dimensional anatomy of the femur considering navigation-aided surgery of total knee arthroplasty in Japanese patients.

PURPOSE: Few studies exist regarding sagittal alignment describing femur morphology in navigation-aided surgery. This study investigated the three-dimensional (3D) sagittal femoral alignment of the whole femur. METHODS: Seventy-three consecutive patients (59 females, 14 males, mean age: 76.1 years), yielding 140 femurs, were included in this study. A computed-tomography-based patient-specific 3D femur model was used to define a mechanical axis-based reference plane. Proximal and distal femoral axis angles (PFA, DFA) to the reference plane were measured in 3D using custom software. PFA and DFA represent the proximal and distal inclination of the femoral anatomical axis in sagittal plane, respectively. RESULTS: PFA (10.6 ± 1.5°) was greater than DFA (2.6 ± 1.6°; P < 0.0001). DFA in females (2.3 ± 1.4°) was smaller than in males (3.9 ± 1.7°; P < 0.0001). CONCLUSION: This is the first report of measurement of femoral sagittal alignment related to both 3D anatomy and decision making of femoral flexion angle using navigation surgery for total knee arthroplasty. This report shows a robust DFA measurement that could be used as a template for femoral implants flexion angle when performing both conventional and navigated total knee arthroplasty.

Racial Disparities in Rates of Revision and use of Modern Features in Total Knee Arthroplasty, a National Registry Study.

BACKGROUND: The purpose of our study was to investigate the association of race and ethnicity with rates of modern implant use and postoperative outcomes in total knee arthroplasty (TKA) using the American Academy of Orthopaedic Surgeons American Joint Replacement Registry. METHODS: Adult TKAs from 2012 to 2020 were queried from the American Joint Replacement Registry. A total of 1,121,457 patients were available for analysis for surgical features and 1,068,210 patients for analysis of outcomes. Mixed-effects multivariable logistic regression models were used to examine the association of race with each individual surgical feature (unicompartmental knee arthroplasty (UKA) and robotic-assisted TKA (RA-TKA)) and 30- and 90-day readmission. A proportional subdistribution hazard model was used to model the risk of revision TKA. RESULTS: On multivariate analyses, compared to White patients, Black (odds ratio (OR): 0.52 P < .0001), Hispanic (OR 0.75 P < .001), and Native American (OR: 0.69 P = .0011) patients had lower rates of UKA, while only Black patients had lower rates of RA-TKA (OR = 0.76 P < .001). White (hazard ratio (HR) = 0.8, P < .001), Asian (HR = 0.51, P < .001), and Hispanic-White (HR = 0.73, P = .001) patients had a lower risk of revision TKA than Black patients. Asian patients had a lower revision risk than White (HR = 0.64, P < .001) and Hispanic-White (HR = 0.69, P = .011) patients. No significant differences existed between groups for 30- or 90-day readmissions. CONCLUSION: Black, Hispanic, and Native American patients had lower rates of UKA compared to White patients, while Black patients had lower rates of RA-TKA compared to White, Asian, and Hispanic patients. Black patients also had higher rates of revision TKA than other races.

Coronal and axial alignment relationship in Caucasian patients with osteoarthritis of the knee.

Individualized pre-operative assessment of the patterns of the lower extremity anatomy and deformities in patients undergoing total knee arthroplasty seems essential for a successful surgery. In the present study, we investigated the relationship among the coronal alignment and the rotational profile of the lower extremities in the Caucasian population with end-stage knee osteoarthritis. We conducted a prospective study of 385 knees that underwent a pre-operative three-dimensional computed tomography-based model. The lower extremity alignment was determined (mechanical tibiofemoral or hip-knee-ankle angle, supplementary angle of the femoral lateral distal angle, and proximal medial tibial angle). For each case, the femoral distal rotation (condylar twist angle), the femoral proximal version, and the tibial torsion were determined. As the coronal alignment changed from varus to valgus, the femoral external rotation increased (r = 0.217; p < 0.0005). As the coronal alignment changed from varus to valgus, the external tibial torsion increased (r = 0.248; p < 0.0005). No correlation was found between the global coronal alignment and the femoral version. The present study demonstrates a linear relationship between the coronal alignment and the rotational geometry of the distal femur. This correlation also occurs with the tibial torsion. Perhaps outcomes of total knee arthroplasty surgery might be improved by addressing these deformities as well.

The IL-6 rs12700386 polymorphism is associated with an increased risk of developing osteoarthritis in the knee in the Chinese Han population: a case-control study.

BACKGROUND: This case-control study aims to examine the association between the Interleukin-6 (IL-6) rs12700386 polymorphism and the increased risk of developing osteoarthritis (OA) in the knee in the Chinese Han population. METHODS: We extracted DNA from 763 subjects (352 OA patients and 411 healthy controls). The relative expression levels of IL-6 in blood samples of patients with knee OA was determined by quantitative reverse transcription PCR (qRT-PCR) and polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) was used for genotyping the IL-6 gene polymorphism. RESULTS: We found that the IL-6 polymorphism rs12700386 enhanced patient susceptibility to developing knee OA. Based on a subgroup analysis, the risk of developing knee OA was elevated in smokers, drinkers, and subjects ≥55 years old or with BMI ≥ 25 kg/m2. The combination of smoking, drinking, and having the rs12700386 genotype led to an increase in the risk of developing knee OA, indicating that an underlying interaction between gene and environment exists. The rs12700386 genotype was found to be correlated with an increase in IL-6 expression. We also found that IL-6 levels were significantly higher in the CC genotype compared to the GG genotype carriers in OA patients. CONCLUSION: These data suggest that the rs12700386 polymorphism in the IL-6 gene leads to an increase in the risk of knee OA in Chinese Han individuals.

Cross-cultural translation and validation of the Chinese Oxford Knee Score and the Activity and Participation Questionnaire.

OBJECTIVE: To cross-culturally translate and validate the Chinese versions of the Oxford Knee Score (OKS) and the Activity and Participation Questionnaire (APQ) in patients with end-stage knee osteoarthritis who are also candidates for knee replacement. METHODS: The Chinese version of the OKS and APQ was completed by standard forward-backward translation and adaption. The feasibility was validated by a pretest in 30 patients. The final version together with the Short Form-36 (SF-36), EQ-5D, and EQ visual analog scale were assessed in 150 patients, and the OKS and APQ were repeated in 30 patients after a 2-week interval. The psychometric properties of the OKS and APQ were evaluated for test-retest reliability using intraclass correlation coefficients (ICCs), internal consistency using Cronbach's α, and construct validity using Spearman's correlation analysis. RESULTS: All patients were able to understand and complete both the OKS and APQ without difficulty (i.e. no missing data). The ICCs were 0.959 for the OKS, 0.956 for the APQ for total scores, and >0.7 for each item. Cronbach's α was greater than 0.7, and the corrected item-total correlation was greater than 0.4 for each item of both questionnaires. The OKS and APQ showed better correlations with questions from the pain and function domains than with those from the mental status domains of the SF-36 and EQ-5D. No floor or ceiling effect was identified in either questionnaire. CONCLUSIONS: The Chinese versions of the OKS and APQ are easy to understand and complete and showed good reliability and validity. They can be used to assess patient-reported outcomes after undergoing knee replacement in mainland China.

Genetic estrogen receptor alpha gene PvuII polymorphism in susceptibility to knee osteoarthritis in a Chinese Han population: A southern Jiangsu study.

BACKGROUND: Knee osteoarthritis (KOA) is the most prevalent type of arthritis and genetic factors play an important role in KOA pathogenesis. Some studies have reported the association of estrogen receptor alpha (ESRα) gene polymorphism and KOA susceptibility in different populations. This study was designed to verify whether ESRα gene polymorphism (rs2234693) was associated with primary KOA in a Chinese Han population living in the south of Jiangsu. METHODS: A case-control association study on single nucleotide polymorphism (SNP) rs2234693 was performed, and a total of 1953 subjects (1033 OA cases and 920 controls) were genotyped. Allele and genotype frequencies were compared between KOA cases and control participants. RESULTS: SNP rs2234693 was significantly associated with KOA in the dominant genetic model (TT + TC vs. CC) in all the subjects (odds ratio (OR) = 1.30; 95% confidence interval (CI) = 1.02-1.66; P = .03), and T allele frequency was also higher compared with allele C (OR = 1.38; 95% CI = 1.06-1.80; P = .02). After stratification by gender, there was no evident difference between the two groups in female and male subjects (P > .05). With a stratification for KOA severity, the combined genotype (TT + TC) (OR = 1.47; 95% CI = 1.12-1.94; P < .01) and T allele (OR = 1.61; 95% CI = 1.19-2.19; P < .01) were evidently associated with mild KOA, but not with severe KOA. CONCLUSIONS: ESRα gene is of considerable importance in the pathogenesis of early-stage KOA in a Chinese Han population living in southern Jiangsu.

Geographical and ethnic differences of osteoarthritis-associated hip and knee replacement surgeries in New Zealand: a population-based cross-sectional study.

OBJECTIVES: To (1) explore the regional and ethnic differences in rates of publicly funded osteoarthritis-associated hip and knee replacement surgeries and (2) investigate the mortality after surgery. DESIGN: Population-based, retrospective, cross-sectional study. SETTING: General population in New Zealand. PARTICIPANTS: Patients with osteoarthritis who underwent publicly funded primary hip and knee replacement surgeries in 2005-2017. Patients aged 14-99 years were included. PRIMARY AND SECONDARY OUTCOME MEASURES: Age-standardised rate, standardised mortality ratio (SMR) and 30 days, 90 days and 1 year mortality. RESULTS: We identified 53 439 primary hip replacements and 50 072 primary knee replacements with a diagnosis of osteoarthritis. The number and age-standardised rates of hip and knee replacements increased over time. Maori had the highest age-standardised rate of hip replacements, followed by European/others and Pacific, and Asian had the lowest rate. Pacific had the highest age-standardised rate of knee replacements, followed by Maori and European/others, and Asian had the lowest rate. The Northern Health Network had the lowest rate of hip surgeries, and the Southern Health Network had the lowest rate of knee surgeries. The SMRs of patients undergoing hip and knee replacements were lower than the general population: 0.92 (95% CI 0.89 to 0.95) for hip and 0.79 (95% CI 0.76 to 0.82) for knee. The SMRs were decreasing over time. The patterns of 30 days, 90 days and 1 year mortality were similar to the SMR. CONCLUSIONS: The numbers of publicly funded osteoarthritis-associated primary hip and knee replacements are steadily increasing. Maori people had the highest age-standardised rate of hip replacements and Pacific people had the highest rate of knee replacements. The Northern Health Network had the lowest rate of hip surgeries, and the Southern Health Network had the lowest rate of knee surgeries. Compared with the general population, patients who had hip and knee replacements have a better life expectancy.

A comparison of clinical and patient-reported outcome measures of TKR: Comparison of Asian to North American patients.

BACKGROUND: Cultural differences between continents may also affect the outcome on interventions. This study compared an Asian and North American cohort of total knee replacement (TKR) patients. QUESTIONS/PURPOSES: This study aims to compare the patient-reported outcome measures as well as a functional outcome after TKR between these two different patient populations with a different cultural societal background in two different countries. PATIENTS AND METHODS: A retrospective study on two cohorts of 76 Asian TKR patients and 64 North American TKR patients were compared. Demographics, patient-reported outcome measures (Knee Society Score (KSS), Patient-Administered Questionnaire (PAQ), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)), knee range of motion (RoM), and radiographic component position were compared. RESULTS: The Asian cohort had more females compared to the North American and significantly worse preoperative RoM, and worse KSS function score and PAQ pain scores. The preoperative KSS knee score and WOMAC scores were comparable between the two groups. Postoperatively, the differences in WOMAC and KSS knee scores were significant, while KSS function and PAQ were comparable between groups. CONCLUSIONS: Even though Asian TKR patients had significantly worse preoperative scores, their postoperative outcomes were comparable to North Americans. The higher preoperative functional deficit and the higher pain levels in the Asian population might be due to cultural differences and/or socioeconomic reasons, which made Asian patients present with more severe conditions in the preoperative consultation for a possible surgical treatment compared to North Americans. More research is needed to investigate the difference between these cultural impacts on TKR outcomes. LEVEL OF EVIDENCE: Level III/Retrospective cohort study.

Greater Rates of Acute Kidney Injury in African American Total Knee Arthroplasty Patients.

BACKGROUND: This retrospective study compared the change in serum creatinine between African American and Caucasian total knee arthroplasty (TKA) patients. The authors hypothesized that African Americans would demonstrate significantly greater change, and that a significantly greater proportion would demonstrate creatinine changes consistent with acute kidney injury (AKI). METHODS: Primary TKAs performed at a single institution between July 2011 and June 2016 were identified: 1035 primary TKAs met inclusion and exclusion criteria (110 African American, 925 Caucasian, excluding Hispanic and Asian patients). None were excluded based on gender, age, body mass index, preoperative diagnosis, or comorbidities. All patients had preoperative and postoperative creatinine levels available in the electronic medical records. Each patient received the same preop and postop protocol for nonsteroidal anti-inflammatory drug use along with other drugs administered including anesthesia. All patients received 1 g of intravenous vancomycin with some patients additionally receiving 1 g of vancomycin powder administered locally at the end of surgery. All patients were controlled for fluid intake and blood loss, along with no patient receiving a transfusion or intravenous contrast. Patient demographics and preoperative/postoperative serum creatinine were recorded and then analyzed for presence of AKI (≥0.3 mg/dL). Preoperative/postoperative serum creatinine concentrations were compared between African American and Caucasian patients using 2 × 2 repeated measures analysis of variance. Prevalence of patients in each group demonstrating AKI was calculated using Fisher's exact test. RESULTS: African American patients had significantly greater serum creatinine preoperatively (1.00 ± 0.26 vs 0.90 ± 0.22, P < .001) and a significantly greater increase postoperatively (0.10 vs 0.03, P < .001). A significantly greater number of African American patients demonstrated AKI (10.9% vs 5.1%, P = .03). Furthermore, a significantly greater number of African American patients stayed in the hospital an additional 2 or more days for renal issues (2.7% vs 0.4%, P = .03). CONCLUSION: Altered renal function was significantly more common in African American TKA patients. Future studies are necessary to determine if tailoring anti-inflammatories, perioperative medications, and preoperative comorbidities reduce the risk of renal injury and/or a longer hospital stay for this subset of patients.

The Effect of Payer Type on Patient-Reported Outcomes in Total Joint Arthroplasty Is Modulated by Baseline Patient Characteristics.

BACKGROUND: Patient-reported outcomes (PROs) are gaining an important role in the assessment of quality of care. There are currently limited data on the effect of payer type on PROs in total joint arthroplasty (TJA). This study compared both disease-specific and general health PROs among patients stratified according to their payer type. METHODS: Our institutional joint registry was queried for patients who underwent primary, elective, and unilateral hip and knee arthroplasty. Patients were divided according to their insurance type at the time of surgery into 3 groups: Medicaid, Medicare, or commercial. The outcomes assessed were the net changes in PROs as well as absolute scores at 6 months and 1 year. Six of the most commonly used PROs were assessed: Short Form-12 physical and mental components, Western Ontario and McMaster Universities Osteoarthritis Index, Single Assessment Numerical Evaluation, University of Californian Los Angeles activity level rating, and Oxford Hip Score. Analysis of variance and covariance were used. RESULTS: We evaluated 756 procedures (273 Medicaid, 270 Medicare, and 213 commercial insurance). Medicaid patients had significantly lower mean baseline scores across all PROs compared to either Medicare or commercial insurance patients. Medicaid patients were also more likely to be smokers, live alone, have lower educational level, African-American, and have nonprimary osteoarthritis as the indication for TJA. At 1-year follow-up, the net mean outcome gains were comparable among the 3 payer types (P > .05), but Medicaid patients continued to score lower while Medicare and commercial insurance patients continued to score higher (P < .01). When adjusting for all baseline differences among Medicaid patients, the negative effects of payer type resolved except for Oxford Hip Score which remained lower in the Medicaid group (P = .006). CONCLUSION: When using PROs to assess the value of care, the preoperative to postoperative changes are a better indicator of surgical success than comparing absolute values, especially in Medicaid patients. While TJA imparts similar net improvements to patients of all payer types, Medicaid coverage is a predictor of lower absolute outcome scores at any given time as result of increased baseline health burden (eg, depression, tobacco smoking, and poor overall well-being). Arthroplasty surgeons should be aware of these factors when counseling patients and seek optimization when necessary. The findings should be taken into account by stakeholders when constructing value-based payment models. Further research is needed to better understand the barriers leading to higher prevalence of increased health disparities among Medicaid beneficiaries and how to effectively address them.

Correlation between Interleukin-17 gene polymorphism and osteoarthritis susceptibility in Han Chinese population.

BACKGROUND: Interleukin-17 (IL-17), a pleiotropic cytokine, plays a significant role in the inflammatory diseases. By a pilot study with small population, IL-17 polymorphisms (IL-17A rs2275913 and IL-17F rs763780) showed a more potential risk factor in knee osteoarthritis (OA) in our recruited subjects. In the current study, the association between IL-17A rs2275913 and IL-17F rs763780and the risk of OA in a Chinese population is studied. METHODS: The IL-17A rs2275913 and IL-17F rs763780 polymorphisms were determined in 594 knee OA cases and 576 healthy controls, using polymerase chain reaction-restriction fragment length polymorphism assay. The relationship between genotype distribution and disease risk, as well as OA severity was analyzed by Chi-square test and multivariate logistic regression. RESULTS: The experimental results indicated that the polymorphism in IL-17 gene rs2275913 site were related to knee OA risk after the adjustment of BMI, sex, age, smoking and drinking status (AA vs. GG: odds ratio (OR), 1.411; 95% confidence interval (CI), 1.021-1.950; P = 0.040; A allele vs. G allele: OR, 1.192; P = 0.037; 95% CI, 1.012-1.404;). Similarly, subjects who are bearing the rs763780 variant genotypes (TC and CC) and C allele also had a higher susceptibility to knee OA compared with those who are bearing the TT genotype (TC vs. TT, OR: 1.312; P = 0.039; 95% CI: 1.017-1.692; CC vs. TT, OR: 2.812, P = 0.006, 95% CI: 1.338-5.909; C allele Vs. T allele, OR:1.413, P = 0.002, 95% CI:1.141-1.751). In the meantime, one high-risk haplotypes, AC (OR was 7.22, P < 0.01) was found. Both two polymorphisms do not correlated with OA severity based on Kellgren-Lawrence (K&L) scales. Finally, serum IL-17 levels of knee OA patients were greatly higher than those of controls (P = 0.001). CONCLUSIONS: With the limited size sample, our study shows that IL-17 gene polymorphisms possibly related to the high-risk knee OA occurrence.

Femoral Component Sizing in Oxford Unicompartmental Knee Replacement: Existing Guidelines Do Not Work for Indian Patients.

Oxford unicompartmental knee replacement (OUKR) has shown excellent long-term clinical outcomes as well as implant survival when used for correct indications with optimal surgical technique. Anteromedial osteoarthritis is highly prevalent in Indian patients, and OUKR is the ideal treatment option in such cases. Uncertainty prevails about the best method to determine femoral component size in OUKR. Preoperative templating has been shown to be inaccurate, while height- and gender-based guidelines based on European population might not apply to the Indian patients. Microplasty instrumentation introduced in 2012 introduced the sizing spoon, which has the dual function of femoral component sizing and determining the level of tibia cut. We aimed to check the accuracy of sizing spoon and also to determine whether the present guidelines are appropriate for use in the Indian patients. A total of 130 consecutive Oxford mobile bearing medial cemented UKR performed using the Microplasty instrumentation were included. The ideal femoral component size for each knee was recorded by looking for overhang and underhang in post-operative lateral knee radiograph. The accuracy of previous guidelines was determined by applying them to our study population. Previously published guidelines (which were based on Western population) proved to be accurate in only 37% of cases. Hence, based on the demographics of our study population, we formulated modified height- and gender-based guidelines, which would better suit the Indian population. Accuracy of modified guidelines was estimated to be 74%. The overall accuracy of sizing spoon (75%), when used as an intraoperative guide, was similar to that of modified guidelines. Existing guidelines for femoral component sizing do not work in Indian patients. Modified guidelines and use of intraoperative spoon should be used to choose the optimal implant size while performing OUKR in Indian patients.

Achieving Minimum Clinically Important Difference in Oxford Knee Score and Short Form-36 Physical Component Summary Is Less Likely with Single-Radius Compared with Multiradius Total Knee Arthroplasty in Asians.

Single-radius (SR) and multiradius (MR) total knee arthroplasties (TKAs) have produced similar outcomes, albeit most studies originate from Western nations. There are known knee kinematic differences between Western and Asian patients after TKA. The aim of this study is to compare the short-term patient-reported outcome measures (PROMs) of SR-TKA versus MR-TKA in Asians. Registry data of 133 SR-TKA versus 363 MR-TKA by a single surgeon were analyzed. Preoperative and 2-year postoperative range of motion (ROM) and PROMs were compared with Student's t-test and Mann-Whitney U-test. Logistic regression model was used to evaluate the odds of SR-TKA or MR-TKA achieving the minimum clinically important difference (MCID) of studied outcomes. Patients in both groups had similar age (65.7 ± 7.6 vs. 65.8 ± 8.2 years; p = 0.317), gender proportion (71% females vs. 79% females; p = 0.119), and ethnic distribution (80% Chinese vs. 84% Chinese; p = 0.258). Preoperatively, there were no statistically significant differences between both groups for ROM, Knee Society Score (KSS), Oxford Knee Score (OKS), and Short Form (SF)-36 scores. At 2 years, all outcomes were statistically similar or failed to achieve a difference of MCID. Controlling for all preoperative variables, SR-TKA has significantly lower odds of achieving MCID for OKS (odds ratio [OR]: 0.275, 95% confidence interval [CI]: 0.114-0.663; p = 0.004) and SF-36 Physical Component Summary (PCS) (OR: 0.547; 95% CI: 0.316-0.946; p = 0.031) compared with MR-TKA. In conclusion, there are no significant differences in the absolute PROMs between SR-TKA and MR-TKA at 2 years following TKA in Asians. However, SR-TKA has significantly lower odds of achieving the MCID for OKS and SF-36 PCS.

Association of Asian mitochondrial DNA haplogroup B with new development of knee osteoarthritis in Koreans.

AIM: The aim of this study was to determine which mitochondrial DNA (mtDNA) haplogroup is associated with new development of knee osteoarthritis (OA). METHODS: Epidemiologic data and knee radiographs with the Kellgren-Lawrence (K/L) score of the Ansung cohort study were prospectively obtained from the 2nd (2005-2006) and 6th follow-up periods (2013-2014). The mtDNA was analyzed by multiplex mutagenetically separated polymerase chain reaction to determine Asian mtDNA haplogroups (M, G, D, D4, D5, M7, M8, M9, M10, N, A, N9, R, F and B). The frequency of the mtDNA haplogroup was compared between participants with knee OA (K/L score ≥2 or total knee replacement arthroplasty [OA group]) and those without knee OA (K/L < 2 [control group]) at the 6th follow-up. Multiple logistic regression was used to determine the relative risk (RR) of mtDNA haplogroups for OA by adjusting for sex, age, body mass index, smoking and metabolic syndrome. RESULTS: There were 1115 participants with epidemiological data, knee radiographs and DNA samples. Of these, 572 participants had a K/L score of 0 at the 2nd follow up, and 438 underwent knee radiography at the 6th follow up. Among the 438 participants, 160 were classified as having knee OA, and 278 were classified as the control group. The haplogroup B showed a significantly higher frequency in the OA group than in the control group (unadjusted RR = 1.794, P = 0.030; adjusted RR = 2.389, P = 0.004). CONCLUSION: Our data suggest that mtDNA haplogroup B contributed to the new development of knee OA in Koreans.

The Impact of Diabetes on Patient Outcomes After Total Knee Arthroplasty in an Asian Population.

BACKGROUND: Diabetes is implicated with poorer outcomes and more complications after total knee arthroplasty (TKA). We aim to determine whether diabetes affects infection risk, functional outcomes, patient-reported outcome measures, and patient satisfaction in Asian patients after TKA. METHODS: Prospectively collected data for 905 patients who underwent unilateral TKA by a single surgeon from February 2004 to July 2014 were reviewed, of which 123 (13.6%) patients suffered from diabetes. At 2-year follow-up, the change in range of motion of the operated knee, body mass index, Knee Society Score, Oxford Knee Score (OKS), and Short Form-36 from baseline was compared between diabetic and nondiabetic patients. We also analyzed the length of hospitalization stay, infection risk, and patient satisfaction between the 2 groups. RESULTS: Compared with nondiabetic patients, diabetic patients had significantly poorer preoperative OKS (37.6 on 8.3 to 35.8 .38.0, P = .02) and Short Form-36 Mental Component Score (48.3 Me11.2 to 51.7 1.10.7, P = .01). At 2-year follow-up, diabetes continued to be associated with poorer OKS of 21.2 018.4 and Knee Society Score Function score of 64.7 Fu20.9 compared to 19.1 0.6.2 (P = .02) and 71.8 0220.1 (P = .01) respectively in nondiabetic patients. Interestingly, the difference in mental well-being was no longer significant after TKA. A significantly larger proportion of diabetic patients (50%) had a reduction in body mass index after TKA compared to 36% in nondiabetic patients (P < .01). There was no difference in range of motion, length of hospitalization stay, infection risk, and patient satisfaction. CONCLUSION: Despite poorer physical scores throughout, diabetic patients are no less satisfied and had significantly greater improvement in mental well-being and weight reduction after surgery.

Simplified Chinese version of hip and knee replacement expectations surveys in patients with osteoarthritis and ankylosing spondylitis: cross-cultural adaptation, validation and reliability.

BACKGROUND: The Hospital for Special Surgery Hip Replacement Expectations Survey (HSS-THRES) and Knee Replacement Expectations Survey (HSS-TKRES) are widely used tools developed to assess patients' preoperative expectations for total hip and knee arthroplasty. This study aimed to translate and adapt the HSS-THRES and HSS-TKRES into Chinese versions (SC-THRES/TKRES) and evaluate their psychometric properties in patients with osteoarthritis (OA) and ankylosing spondylitis (AS). METHODS: Patients scheduled for total hip (104 hip OA and 51 AS) or knee replacements (101 knee OA) were recruited in this study. Confirmatory Factor Analysis (CFA) was used to evaluate structural validity. The internal consistency was assessed by the Cronbach's α coefficient. The intraclass correlation coefficient (ICC) was used to assess test-retest reliability. The construct validity was analyzed by evaluating the correlations between SC-THRES/TKRES and the Expectation WOMAC. The correlations with the Expectation WOMAC were tested against our hypotheses. We additionally compared preoperative expectations of AS patients to those of hip OA patients. RESULTS: The results of CFA for the SC-THRES and SC-TKRES demonstrated good fit. The results for the SC-THRES/TKRES revealed good test-retest reliability and good internal consistency (AS: ICC = 0.893, Cronbach's α = 0.815; hip OA: ICC = 0.878, Cronbach's α = 0.814; knee OA: ICC = 0.806, Cronbach's α = 0.808). The correlations between the SC-THRES/TKRES and the Expectation WOMAC were moderate (0.541 for AS, 0.490 for hip OA and 0.465 for knee OA), which were consistent with the hypotheses. CONCLUSION: The SC-THRES/TKRES are reliable, valid for the evaluation of Chinese patients with OA and AS undergoing total hip and knee arthroplasty. The surveys can be used as part of preoperative assessments. Meanwhile, additional research is needed to replicate these findings and to assess the content validity in a larger sample.

Bearing Dislocation and Progression of Osteoarthritis After Mobile-bearing Unicompartmental Knee Arthroplasty Vary Between Asian and Western Patients: A Meta-analysis.

BACKGROUND: Implant survivorship is reported to be lower and complications, particularly bearing dislocation, are reported to be more frequent in Asian than in Western patients with medial knee osteoarthritis (OA) undergoing Oxford® Phase III unicompartmental knee arthroplasty (UKA). To date, however, these complications have not been compared between these groups of patients. QUESTIONS/PURPOSES: The purpose of this study was to perform a meta-analysis comparing the standardized incidence rates of (1) all-cause reoperation; (2) reoperation related to bearing dislocation; and (3) reoperation related to progression of lateral compartment arthritis in Asian and Western patients with medial knee OA who underwent Oxford Phase III UKA. METHODS: We searched MEDLINE® (January 1, 1976, to May 31, 2017), EMBASE® (January 1, 1985, to May 31, 2017), and the Cochrane Library (January 1, 1987, to May 31, 2017) for studies that reported complications of Oxford Phase III UKAs. Studies were included if they reported reoperation rates attributable to bearing dislocation and/or progression of lateral knee OA after surgery with this implant. Twenty-seven studies were included in this systematic review and 16 studies with followups > 5 years were included in the meta-analysis. These rates were converted to standardized incidence rate (that is, reoperations per 100 observed component years) based on mean followup and number of involved knees in each study. After applying prespecified inclusion and exclusion criteria, the studies were categorized into two groups, Asian and Western, based on hospital location. Twenty-five studies, containing 3152 Asian patients and 5455 Western patients, were evaluated. Study quality was assessed by the modified Coleman Methodology score (MCMS). Although all studies were Level IV, their mean MCMS score was 66.92 (SD, 8.7; 95% confidence interval [CI], 63.5-70.3), indicating fair quality. Because the heterogeneity of all subgroup meta-analyses was high, a random-effects model was used with estimations using the restricted maximum likelihood method. RESULTS: There was no difference in the proportion of Asian patients versus Western patients undergoing reoperation for any cause calculated as 100 component observed years (1.022 of 3152 Asian patients; 95% CI, 0.810-1.235 versus 1.300 of 5455 Western patients; 95% CI, 1.067-1.534; odds ratio, 0.7839; 95% CI, 0.5323-1.1545; p = 0.178). The mean reoperation rate attributable to bearing dislocation per 100 observed years was higher in Asian than in Western patients (0.525; 95% CI, 0.407-0.643 versus 0.141; 95% CI, 0.116-0.166; odds ratio, 3.7378; 95% CI, 1.694-8.248; p = 0.001) Conversely, the mean reoperation rate attributable to lateral knee OA per 100 observed years was lower in Asian than in Western patients (0.093; 95% CI, 0.070-0.115 versus 0.298; 95% CI, 0.217-0.379; odds ratio, 0.3114; 95% CI, 0.0986-0.9840; p < 0.001). CONCLUSIONS: Although total reoperation rates did not differ in the two populations, reoperation for bearing dislocation was more likely to occur in Asian than in Western patients, whereas reoperation for lateral knee OA progression was more likely to occur in Western than in Asian patients after Oxford Phase III UKA. Although possible explanations for these findings may be hypothesized, additional randomized, prospective comparative studies are needed. However, better survival outcomes after UKA may require consideration of ethnicity and lifestyle choices in addition to traditional surgical technique and perioperative care. LEVEL OF EVIDENCE: Level III, therapeutic study.

Comparison of Clinical Results and Injury Risk of Posterior Tibial Cortex Between Attune and Press Fit Condylar Sigma Knee Systems.

BACKGROUND: We compared clinical and radiographic results after total knee arthroplasty (TKA) using Attune and Press Fit Condylar Sigma, and investigated whether use of the current prosthesis increased injury risk to the tibial cortex in Asian patients. We also assessed whether a preoperative posterior tibial slope angle (PSA) is associated with the injury when using the current prosthesis. METHODS: The 300 TKAs with Attune (group A) were compared to the 300 TKAs with Press Fit Condylar Sigma (group B). Demographics were not different, except follow-up periods (24.8 vs 33.3 months, P < .001). The Western Ontario and McMaster Universities Index and range of motion were compared. A minimum distance between tibial component stem and posterior tibial cortex (mDSC) was compared. The correlation between preoperative PSA and mDSC was analyzed in group A. RESULTS: The postoperative Western Ontario and McMaster Universities Index and range of motion of group A were better than those of group B (17.7 vs 18.8, P = .004; 131.4° vs 129.0°, P = .008). The mDSC was shorter in group A (6.3 vs 7.0 mm, P < .001), which made up a higher proportion of the high-risk group for posterior tibial cortical injury with an mDSC of <4 mm (20.0% vs 10.7%, P = .002). A negative correlation was found between the preoperative PSA and mDSC in group A (r = -0.205, P < .001). CONCLUSION: The TKA using the current prosthesis provided more satisfactory results than the TKA using the previous prosthesis. However, the injury risk to the posterior tibial cortex increased in the knees with a large PSA when using the current prosthesis for Asian patients.

Comparison of patellar tracking according to different angles of external rotation of femoral component in varus knee of Asians.

PURPOSE: Racial difference in the femoral geometry may exist. Asian femurs may be more externally rotated. If anatomical differences in distal femur had existed between Caucasians and Asians, the group with 5° external rotation of the femoral component should have shown better results than the group with 3° external rotation of the femoral component have. METHODS: 598 patients underwent total knee arthroplasty in our institution, among whom 83 patients (115 knees) who had postoperative computed tomography (CT) were studied retrospectively. Sixty-two knees were set in 5° of external rotation of femoral component relative to the posterior condylar axis (group A) while the others (53 knees) were set in 3° (group B). The femoral component rotation (FCR) was measured and compared using CT. The patellar tilting (PT) and the lateral patellar displacement (LPD) were measured to evaluate the patellar tracking using Merchant view. And postoperative clinical scores were compared. RESULTS: The mean FCRs showed no significant difference between two groups ( p > 0.05). The mean PT and LPD showed no statistically significant difference either ( p > 0.05). There were no statistical differences in clinical scores. CONCLUSION: The difference in the patellar tracking between the two groups could not be demonstrated. There were no statistical differences in clinical scores either. We concluded there is no need to adhere to 5° external rotation.

An updated meta-analysis of the asporin gene D-repeat in knee osteoarthritis: effects of gender and ethnicity.

BACKGROUND: Knee osteoarthritis (KOA) is the most prevalent form of knee joint disease and characterized by the progressive degeneration of articular cartilage. Although pathology of KOA remains unknown, genetic factors are considered to be the major cause. Asporin is a group of biologically active components of extracellular matrix (ECM) in articular cartilage, and asporin gene (ASPN) D-repeat polymorphism was reported to be associated with KOA. Thus, our meta-analysis is aimed at investigation of the association between asporin D-repeat polymorphism and susceptibility of KOA. METHODS: We gathered data from MEDLINE, Embase, OVID, and ScienceDirect to search relevant published epidemiological studies through April 2017. Compared with previous studies, our meta-analysis is the first study to investigate the association of ASPN D15, D16, and D17 alleles and KOA susceptibility by ethnic- and sex-stratified subgroup analysis. RESULTS: We found no significant association between D15 allele and susceptibility to KOA (OR = 1.05, 95% CI 0.95-1.17) in overall population. The same results were observed in the analysis of D16 (OR = 1.01, 95% CI 0.80-1.28) and D17 alleles (OR = 1.28, 95% CI 0.91-1.80). The ethnic- and sex-subgroup analyses did not alter the ORs. However, significant association was detected in the sensitivity analysis of D17 in overall population (OR = 1.05, 95% CI 0.95-1.17) and Asian population (OR = 1.78, 95% CI 1.02-3.11, P < 0.05). CONCLUSION: Our results indicated that D-repeat polymorphism of ASPN may not play a major role in susceptibility of KOA in ethnic- and sex-specific analysis. Because of the limitations of the present meta-analysis, firm conclusions could not be drawn based on the current evidence, and further studies are required to detect genuine role of ASPN.