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Purposes: Due to the morphological diversity of deformities, technical difficulties, improperly designed components, and so on, THA remains a challenging task in dysplastic hips, especially in highly dislocated hips. The purpose of this study was to comprehensively evaluate the clinical outcomes of robot-assisted THA in patients with DDH through a large cohort study, including the precision of acetabular cup positioning, indicators of inflammatory response, indicators of muscle damage, and complications., Methods: We retrospectively analyzed patients with DDH who underwent THA in our prospectively constructed joint registry between August 2018 and August 2022. Finally, 147 manual THAs and 147 robotic-assisted THAs were included in the final analysis. Patient demographics, indicators of inflammation, indicators of muscle damage, operative time, Harris hip scores (HHS), and forgotten joint score (FJS) were recorded for analysis. The precision of the positioning of the acetabular component was assessed with plain radiographs., Results: In the Crowe II/III groups, the reconstructed center of rotation (COR) in the robotic-assisted group was closer to the anatomical COR with less variation than the manual group (absolute horizontal distances of COR 3.5 ± 2.8 vs. 5.4 ± 4.9 mm, p < 0.05; absolute vertical distances of COR 6.4 ± 4.1 vs. 11.7 ± 8.2 mm, p = 0.001). For all Crowe subtypes, the robotic-assisted THA significantly increased the proportion of acetabular cups located in the safety zone within 5° (all p < 0.05). Interleukin-6 and creatine kinase levels were slightly lower and significantly different in the robotic-assisted group at three days postoperatively (all p < 0.05)., Conclusions: Compared to the manual technique, the robot-assisted technique improved the precision and reproducibility of acetabular component positioning, particularly in DDH patients with Crowe types II/III. The robotic-assisted technique did not increase operative time, bleeding, complications, or revision rates, and had a slighter early inflammatory response and muscle damage., (© 2024. The Author(s) under exclusive licence to SICOT aisbl.)

Background: There are limited long-term results of using ceramic-on-ceramic (CoC) bearings in total hip arthroplasty (THA) in a large number of patient cohorts. The purpose of this study was to evaluate the minimum 10-year clinical and radiological outcomes and survivorship in a single surgeon series of CoC-THA., Methods: Among the 1,039 patients (1,391 hips) who underwent primary THA at our institution between 2008 and 2011, 49 patients (69 hips) experienced paralysis or death, and 194 patients (239 hips, 19%) were lost to follow-up. The remaining 796 patients (1,083 hips) were assessed at a mean of 11 years (range, 10 to 13 years) using the modified Harris hip score (mHHS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and a questionnaire on articular noises. Survival analysis was used to estimate the survivorship. Radiological evaluation was performed on 869 hips at the final follow-up., Results: Survivorship at 11 years was 98.3% for revision or aseptic loosening, and 98.2% for reoperation. At the final follow-up, the mean mHHS and WOMAC scores were 93 (range, 12 to 100) and 14.4 (range, 3 to 66), respectively. There were 131 (12%) hips that experienced squeaking, but no patient required revision. No fracture of the ceramic was observed. Radiological evaluation at the final follow-up revealed that 3 (0.3%) hips exhibited loosening, 2 (0.2%) had femoral osteolysis, 81(9.3%) acquired radiolucencies, and 35 (4%) showed heterotopic ossification., Conclusion: This CoC bearing for THA had a high survivorship and excellent functional outcomes for at least 10 years., (Copyright © 2022. Published by Elsevier Inc.)

Aims: Periprosthetic joint infection (PJI) is one of the most serious complications after total joint arthroplasty (TJA) but the characterization of the periprosthetic environment microbiome after TJA remains unknown. Here, we performed a prospective study based on metagenomic next-generation sequencing to explore the periprosthetic microbiota in patients with suspected PJI., Methods: We recruited 28 patients with culture-positive PJI, 14 patients with culture-negative PJI, and 35 patients without PJI, which was followed by joint aspiration, untargeted metagenomic next-generation sequencing (mNGS), and bioinformatics analysis. Our results showed that the periprosthetic environment microbiome was significantly different between the PJI group and the non-PJI group. Then, we built a "typing system" for the periprosthetic microbiota based on the RandomForest Model. After that, the 'typing system' was verified externally., Results: We found the periprosthetic microbiota can be classified into four types generally: "Staphylococcus type," "Pseudomonas type," "Escherichia type," and "Cutibacterium type." Importantly, these four types of microbiotas had different clinical signatures, and the patients with the former two microbiota types showed obvious inflammatory responses compared to the latter ones. Based on the 2014 Musculoskeletal Infection Society (MSIS) criteria, clinical PJI was more likely to be confirmed when the former two types were encountered. In addition, the Staphylococcus spp. with compositional changes were correlated with C-reactive protein levels, the erythrocyte sedimentation rate, and the synovial fluid white blood cell count and granulocyte percentage., Conclusions: Our study shed light on the characterization of the periprosthetic environment microbiome in patients after TJA. Based on the RandomForest model, we established a basic "typing system" for the microbiota in the periprosthetic environment. This work can provide a reference for future studies about the characterization of periprosthetic microbiota in periprosthetic joint infection patients., (© 2023. The Author(s).)

Objective: Periprosthetic joint infection (PJI) caused by non-tubercular mycobacteria (NTM) is uncommon but catastrophic. However, conclusive clinical data on PJI caused by NTM are lacking. In this case series and systematic review, the clinical manifestations, diagnosis, and management of NTM PJI are summarized and analyzed., Methods: From 2012 to 2020, we retrospectively analyzed consecutive PJI cases caused by NTM in our institution. A literature review was also conducted from January 2000 to December 2021, utilizing the PubMed, MEDLINE, Cochrane Library, and EMBASE databases to identify all reported NTM-induced PJI cases. The clinical characteristics, demographics, pathogen identification, treatment protocols, and prognosis of NTM PJI were summarized and analyzed., Results: In this retrospective analysis, seven patients infected with NTM following total joint arthroplasty at our institution were included, including six cases of PJI caused by NTM and one case of septic arthritis (SA) caused by NTM. There were six men and one woman, and their average age was 62.3 years. The average interval between TJA and PJI onset was 4 months. The preoperative serological markers, including the mean ESR (51 mm/h), CRP (4.0 mg/dL), fibrinogen (5.7 g/L), and D-dimer (1.1 g/L), were increased. Six patients underwent staged revision surgery, and one patient with SA received antibiotic-loaded bone cement beads to treat the infection. After an average of 33 months of observation following surgical intervention, none of the patients showed any symptoms of infection recurrence. From 2000 to 2021, 68 patients with NTM PJI were found in 39 studies in the published literature. Reinfections occurred within 1 year after arthroplasty in more than half (53.2%) of the patients. M. fortuitum and M. abscesses were the most prevalent rapidly growing mycobacteria (RGM) in all PJI patients, whereas Mycobacterium avium intracellulare (MAC) was the most prevalent slowly growing mycobacterium (SGM). The corresponding antibiotics were amikacin and ethambutol. The rate of culture-negative without specific clinical symptoms was as high as 36.4% (12/33), while 45% (18/40) utilized additional diagnostic techniques such as NGS. A final clinical follow-up record was available for 59 patients (86.7%; mean follow-up period, 29 months), and 10.1% of patients failed to respond to treatment., Conclusion: Orthopaedic surgeons should consider NTM in patients with negative routine cultures who are at risk for Mycobacterium infection. Treatment options rely on the accurate result of microbiologic identification and drug sensitivity testing, and to achieve this, it may be necessary to send multiple culture specimens, extend the culture time, and change the culture medium. Every effort should be made to identify NTM and its various subtypes through modern diagnostic tools if necessary., (© 2023 The Authors. Orthopaedic Surgery published by Tianjin Hospital and John Wiley & Sons Australia, Ltd.)

Purpose: The purpose of this study is to report on the use of Robotic-assisted total joint arthroplasty (RA-TJA) in China as well as the experience and expectations of Chinese doctors regarding this technology., Method: A self-administered questionnaire was used to assess the current status of RA-TJA in China, the practical experience and suggestions for improvement of the technology by joint surgeons who have performed RA-TJA, and the interest and expectations of orthopaedic surgeons who have not used RA-TJA. The questionnaire was administered to all the physicians of the Chinese Association of Orthopedic Surgeons (CAOS)., Result: A total of 372 qualified questionnaires were generated, among which 28% (n = 104) of the respondents had performed RA-TJA, among those who had performed RA-TJA. When asked how helpful the joint replacement robot was actually/expected to be, there was no significant difference between the expected and actual experience of nonusers and users (p ≥ 0.05); the biggest disadvantage of the current development of RA-TJA was perceived as additional charges to the patient by those who had used it, while those who had not used it perceived it as a limitation of their hospital, both of which were significant differences. Most respondents in both groups (used: 94.2%; not used: 91.4%) were confident in the clinical development of the joint replacement robot., Conclusion: This survey provides cross-sectional data on the current status of Chinese joint surgeons using or not using robots in their daily clinical practice. Improving surgical precision was the consensus of most respondents, while high surgical costs and limitations of hospital conditions were barriers to its development in China., (© 2022. The Author(s) under exclusive licence to SICOT aisbl.)

Background: Periprosthetic joint infection (PJI) is one of the worst complications following total joint arthroplasty (TJA). Unfortunately, effective prevention strategies to reduce the burden of PJI have not been fully determined in hip replacement patients with fracture and non-fracture., Objective: This study aimed to analyze and compare the demographic characteristics, microbiological profiles and antibiotic resistance of PJI after hip replacement between patients with fracture and non-fracture., Methods: We retrospectively analyzed the data of 132 patients who treated PJI. There were divided into two groups: non-fracture group (64 patients infected after hip replacement for fracture) and non-fracture group (68 patients infected after hip replacement for non-fracture). Microorganisms were obtained from the synovial fluid and infected necrotic tissue in the joint capsule, medullary cavity, or acetabulum in all patients, and microbiological profiles and antibiotic resistance were evaluated., Results: Coagulase-negative staphylococci (CoNS) were the most common pathogenic microorganisms in all patients. Methicillin-resistant Staphylococcus (MRS) accounted for 25% in all pathogenic microbes. Staphylococci showed high drug resistance rates to clindamycin, levofloxacin, and all of the first- and second-generation cephalosporins. MRS isolates in non-fracture group had higher drug resistance rates to clindamycin and levofloxacin than than those in fracture group. Gram-negative bacilli (GNB) showed high drug resistance rates to Aztreonam, gentamicin and all of the third- and fourth-generation cephalosporins. Furthermore, GNB isolates in the non-fracture group showed higher resistance rates to gentamicin and all of the third- and fourth-generation cephalosporins., Conclusions: MRS isolates in the non-fracture group showed higher drug resistance rates to clindamycin and levofloxacin, and GNB isolates in non-fracture group showed higher drug resistance rates to gentamicin and all of the third- and fourth-generation cephalosporins.

Objective: To introduce the surgical technique of reconstruction of Paprosky type III acetabular defects by 3D printed porous augments., Methods: First, CT scans of pelvis were obtained to establish the 3D reconstruction model of 3D printed porous augment. Then, a nylon pelvis model was printed to simulate operation with the surgeons. At this time, the augment was designed and modified according to the surgeon's suggestions and the 3D printing principles. Eighteen patients with Paprosky type III acetabular defects receiving reconstructive surgery by 3D printed porous augments were included in current study. Their data, including general information, intra-operative findings, imaging results, functional scores, and complications were retrospectively analyzed., Results: The mean follow-up time lasted 33.3 ± 2.0 (24-56) months. The average limb-length discrepancy (LLD) was 31.7 ± 4.2 (3-59) mm preoperatively, 7.7 ± 1.4 (1-21) mm postoperatively (P < 0.0001), and 7.5 ± 1.2 (0-18) mm at the latest follow-up. The mean vertical position of hip center of rotation (HCOR) from the interteardrop line changed from preoperative 50.7 ± 3.9 (23.3-75.3) mm to postoperative 22.9 ± 1.9 (10.1-40.3) mm (P < 0.0001), with the latest follow-up revealing an HCOR of 22.3 ± 1.7 (11.0-40.5) mm. Follow-up study showed that no hip had radiolucencies and radiological loosening of the acetabular components and augment. The average Harris hip score (HHS) improved from 40.3 ± 4.5 (10.5-71) before operation to 88.4 ± 1.9 (75-97) at the last follow-up (P < 0.0001). Moreover, follow-up exhibited that no periprosthetic joint infection, hip dislocation, fracture, and re-revision occurred., Conclusion: Surgical treatment of Paprosky type III acetabular defect with 3D printed porous augment was simple, achieved good match between porous augment and the defect bone surface and the acetabular component, ideally restored LLD and HCOR after operation, significantly improved HHS and attained good early clinical outcomes. It is a promising personalized solution for patients with severe acetabular bone defect., (© 2022 The Authors. Orthopaedic Surgery published by Tianjin Hospital and John Wiley & Sons Australia, Ltd.)

Objective: To report the long-term outcomes of total hip arthroplasty (THA) with fourth-generation ceramic-on-ceramic (CoC) bearing in patients with ankylosing spondylitis (AS)., Methods: We retrospectively identified 180 primary THAs performed in 110 patients with AS, including 100 (90.9%) men and 10 women (9.1%), from 2009 to 2011.The mean age of the patients at surgery was 33 years (range, 16 to 65 years). Cementless prostheses with fourth-generation CoC bearings were used in all patients. Survivorship of the implants and postoperative complications were calculated. Functional improvement was assessed by the hip flexion-extension range of motion (ROM) and Harris hip score (HHS). A special noise assessment questionnaire was performed at the last follow-up. The cumulative incidence of noise was calculated by the Kaplan-Meier method with 95% confidence intervals (CIs). Clinical characteristics and functional outcomes were compared in the hips with noise to those without noise., Results: The mean follow-up was 11 years (range, 10 to 12 years), and survivorship of the implants was 99.4% at the most recent follow-up. The complications included dislocation (one hip, 0.6%), periprosthetic joint infection (one hip, 0.6%), mild to moderate pain (five hips, 2.8%), heterotopic ossification (12 hips, 6.7%), and noise (52 hips, 28.9%). The flexion-extension ROM improved significantly with a median from 10° (range, 0 ~ 130°) to 100° (30 ~ 130°) after THA (p < 0.001), and the HHS increased significantly from 41 ± 20 to 90 ± 8 (p < 0.001). The cumulative incidence of noise at 0.5, 5, and 10 years was 6.1% (95% CI, 2.6 ~ 9.6), 16.7% (95% CI, 11.2 ~ 22.1), and 28.9% (95% CI, 22.2 ~ 35.5), respectively, and that of squeaking at 0.5, 5, and 10 years was 4.4% (95% CI, 1.4 ~ 7.4), 13.3% (95% CI, 8.4 ~ 18.3), and 23.9% (95% CI, 17.6 ~ 30.1), respectively. None of the patients with noise generation in the hip reported it affecting daily activities or causing dissatisfaction. No differences in age, sex, BMI, disease duration, bilateral THA, the frequency of bony ankylosis, the proportion of using a 36-mm-diameter femoral head, pre/postoperative flexion-extension ROM, or pre/postoperative HHS were found between hips with noise and those without noise (p > 0.05)., Conclusion: THAs with fourth-generation CoC bearings exhibit excellent long-term survival and clinical outcomes in patients with AS, with a very low dislocation rate. The incidence of noise associated with CoC bearings in THA performed in patients increases over time, but it does not affect postoperative hip function or daily activities., (© 2022 The Authors. Orthopaedic Surgery published by Tianjin Hospital and John Wiley & Sons Australia, Ltd.)

Objective: To explore the possibility of obtaining more accurate information from routine blood tests for the diagnosis of periprosthetic joint infection (PJI)., Methods: This is a retrospective study. Between 2017 and 2018, a total of 246 patients who underwent total hip or knee revision surgery were included in this study. There were 146 females and 100 males, and the mean age of the patients was 62.1 ± 12.75 years. Laboratory parameters erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), D-dimer, plasma fibrinogen, serum white blood cell (WBC), and calculable ratio markers were collected. Based on leukocytes (monocyte count, neutrophil count, lymphocyte count), platelet count, and mean platelet volume Inflammation-related ratio markers were calculated, which including monocyte to lymphocyte ratio (MLR), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and platelet to mean platelet volume ratio (PMR). Follow-up of all studied cases for at least 1 year. The diagnostic value of the markers based on the receiver operating characteristic (ROC) analysis. The most optimal combinations of blood markers were selected by the prediction models. Statistical analyses and prediction models were performed using R software., Results: Of the 246 patients, 125 were diagnosed with PJI and 121 with aseptic loosening. A higher rate of patients underwent revision surgery due to hip prosthesis loosening in the aseptic loosening group (74.4%) compared to the PJI group (45.6%, P < 0.001). ROC curves showed that the area under the curve (AUC) for classical markers, fibrinogen was 0.853 (95% confidence interval [CI], 0.805-0.901), ESR was 0.836 (95% CI, 0.785-0.887) and CRP was 0.825 (95% CI, 0.773-0.878). Followed by the PMR, PLR, NLR and MLR, which showed promising diagnostic performance with AUCs of 0.791, 0.785, 0.736, and 0.733. The AUCs of the ratio markers were higher than those of D-dimer (0.691;95% CI, 0.6243-0.7584) and serum WBC (0.622; 95% CI, 0.552-0.691). After the predictive model calculation, AUC was up to 0.923 (95% CI, 0.891-0.951) when plasma fibrinogen combined with MLR and PMR and interpreted excellent discriminatory capacity with a sensitivity of 86.40% and a specificity of 84.17%. The new combination significantly increases the accuracy and reliability of the diagnosis of PJI (P < 0.001). The AUC increased to 0.899 (95% CI, 0.861-0.931; P = 0.007) and 0.916 (95% CI, 0.880-0.946; P < 0.001), followed by CRP and ESR, respectively. All plasma fibrinogen, ESR, and CRP combined with both PMR and MLR achieved the highest specificity (89.17%) and PPV (85.34%)., Conclusion: The diagnostic performance greatly improved when plasma fibrinogen, ESR, and CRP combined with ratio markers., (© 2021 The Authors. Orthopaedic Surgery published by Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.)

Aims: Preoperative aspiration culture and intraoperative cultures play pivotal roles in periprosthetic joint infection (PJI) diagnosis and pathogen identification. But the discordance between preoperative aspiration culture and intraoperative synovial fluid culture remains unknown. We aim to determine (1) the discordance between preoperative and intraoperative synovial fluid (SF) culture and. (2) compared to intraoperative synovial fluid cultures, the sensitivity of preoperative aspiration fluid culture. Then the following question is tried to be answered: Are intraoperative synovial fluid re-cultures necessary if the preoperative aspiration culture is positive?, Materials and Methods: Between 2015 and 2019, 187 PJI patients managed with surgeries were included in this study. Compared to intraoperative synovial fluid culture, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of preoperative aspiration culture were calculated. Then, the discordance between preoperative aspiration culture and intraoperative SF culture was analyzed., Results: The sensitivity of preoperative aspiration culture was 81.29% compared to intraoperative synovial fluid cultures. Concordance was identified in 147 PJI (78.61%) patients and culture discordance occurred in 40 patients (21.39%). In these discordant PJI patients, 24 patients (60%) were polymicrobial and no intraoperative synovial fluid culture growth was found in 16 PJI cases (40%). Preoperative monomicrobial staphylococcus results had a sensitivity of and a specificity of 80.43% and 83.16%, respectively. Preoperative polymicrobial results had the lowest sensitivity., Conclusions: The intraoperative synovial fluid re-cultures are necessary if the preoperative aspiration culture is positive and the discordance between preoperative aspiration culture and intraoperative synovial fluid culture should be noted especially when Streptococcus spp. and more than one pathogen was revealed by preoperative aspiration culture., Level of Evidence: Level III., (© 2021. The Author(s).)

Background: Periprosthetic joint infection is a serious complication after total joint arthroplasty and polymicrobial PJI which compose a subtype of PJI often indicate worse outcomes compared to monomicrobial periprosthetic joint infection. However, a literature review suggested that there were limited number studies evaluating the risk factors of polymicrobial PJI., Materials and Methods: Between 2015 January and 2019 December, a total of 64 polymicrobial PJI patients and 158 monomicrobial PJI patients in a tertiary center were included in this study and corresponding medical records were scrutinized. The diagnosis of PJI was based on 2014 MSIS criteria. Logistic regression was used to identify the association between various variables and polymicrobial PJI and ROC curve was used to identify their efficiency., Results: The prevalence of polymicrobial PJI is 28.3% in our cohorts. After adjusting for the presence of sinus, previous and knee infection, isolation of enterococci (OR, 3.025; 95%CI (1.277,7.164) p = 0.012), infection with atypical organisms (OR, 5.032;95%CI: (1.470,17.229) p = 0.01), infection with gram-negative organisms (OR, 2.255; 95%CI (1.011,5.031) p = 0.047), isolation of streptococcus spp. (OR, 6; 95%CI (2.094,17.194) p = 0.001), and infection with CNS (OfR, 2.183;95%CI (1.148,4.152) p = 0.017) were risk factors of polymicrobial PJI compared to monomicrobial PJI. However, knee infection is related to a decreased risk of polymicrobial PJI with an adjusted OR = 0.479 (p = 0.023)., Conclusion: This study demonstrated that the prevalence of polymicrobial PJI is 28.3% in PJI patients. Moreover, the presence of sinus tract and previous joint revisions were risk factors for identifying different bacterial species in the intraoperative specimens. Therefore, in these PJI cases, it is necessary to examine multiple specimens of both intraoperative tissue and synovial fluid for increasing the detection rate and obtaining resistance information., (© 2021. The Author(s).)

Background: This study aimed to investigate the efficacy of the albumin/fibrinogen ratio (AFR) in the assessment of malnutrition and to compare its ability to predict early postoperative periprosthetic joint infection (PJI) in patients with aseptic revisions., Methods: Four hundred sixty-six patients undergoing revision total hip or knee arthroplasty between February 2017 and December 2019 were recruited in this retrospective study. We compared the differences in nutritional parameters between patients undergoing revision for septic and aseptic reasons. We used multivariate logistic regression and assessed the association between nutritional parameters and risk of PJI. 207 patients with aseptic revision were then evaluated for the incidence of acute postoperative infection within 90 days. The predictive ability of nutritional markers was assessed by receiver operating characteristic curves., Results: In the multivariate logistic regression analysis, low albumin level (adjusted OR 1.56, 95% CI 1.16-2.08, P = .003), low prognostic nutritional index (PNI) (adjusted OR 1.57, 95% CI 1.01-2.43, P < .043), and low AFR (adjusted OR 2.54, 95% CI 1.92-3.36, P < .001) were independently associated with revision surgery for septic reasons. In accordance with the receiver operating characteristic analysis, the AFR exhibited a greater area under the curve value (0.721) than did the prognostic nutritional index and albumin. An elevated AFR (≥11.7) was significantly associated with old age, joint type, high Charlson comorbidity index, high American Society of Anesthesiologist, and diabetes (P < .05)., Conclusion: Our findings demonstrated AFR may be an effective biomarker to assess nutrition status and predict acute PJIs after revision TJA., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: To measure and analyze the radiographic characteristics of the leg length discrepancy in adult patients with unilateral developmental dysplasia of the hip (DDH)., Methods: The clinical data of 112 patients with unilateral DDH who met the selection criteria between January 2016 and June 2018 were retrospectively analyzed. There were 16 males and 96 females with an age of 20-76 years (mean, 42.9 years). According to the Crowe classification, there were 25 hips of type Ⅰ, 26 hips of type Ⅱ, 15 hips of type Ⅲ, and 46 hips of type Ⅳ (26 hips of type ⅣA without secondary acetabular formation, and 20 hips of type ⅣB with secondary acetabular formation). Full-length X-ray films of the lower limbs in the standing position were used to measure the following parameters: greater trochanter leg length (GTLL), greater trochanter femoral length (GTFL), lesser trochanter leg length (LTLL), lesser trochanter femoral length (LTFL), tibial length (TL), and intertrochanteric distance (ITD). The above parameters on the healthy and affected sides were compared and the difference of each parameter between the healthy and affected sides was calculated. Taking the difference of 5 mm between the healthy side and the affected side as the threshold value, the number of cases with the healthy side was greater than 5 mm and the affected side was greater than 5 mm were counted respectively. The difference of the imaging parameters between the healthy side and the affected side were compared between different Crowe types and between type ⅣA and type ⅣB., Results: There was no significant difference in GTLL and LTFL between healthy and affected sides ( P >0.05); LTLL and TL of affected side were longer than healthy side, GTFL and ITD were shorter than healthy side, and the differences were significant ( P <0.05). The constituent ratio of long cases on the affected side of TL and LTLL was greater than the constituent ratio of long cases on the healthy side, while the constituent ratio of long cases on the healthy side of GTFL and ITD was greater than the constituent ratio of long cases on the affected side; there was no obvious difference in the constituent ratio of long cases on the healthy side or the affected side of GTLL and LTFL. The comparison between different Crowe types showed that only the difference in TL between type Ⅰ and type Ⅳ was significant ( P <0.05), the difference of each imaging parameter among the other types showing no significant difference ( P >0.05). Compared with type ⅣB, the differences of GTLL, TL, and ITD of type ⅣA were bigger, and the differences were significant ( P <0.05); the differences of other parameters between type ⅣA and type ⅣB were not significant ( P >0.05)., Conclusion: In adult unilateral DDH patients, the leg length on the healthy side and the affected side is different, and the difference mainly comes from the TL and ITD, which should be paid attention to in preoperative planning.

Aims: It can be extremely challenging to determine whether to perform reimplantation in patients who have contradictory serum inflammatory markers and frozen section results. We investigated whether patients with a positive frozen section at reimplantation were at a higher risk of reinfection despite normal ESR and CRP., Methods: We retrospectively reviewed 163 consecutive patients with periprosthetic joint infections (PJIs) who had normal ESR and CRP results pre-reimplantation in our hospital from 2014 to 2018. Of these patients, 26 had positive frozen sections at reimplantation. The minimum follow-up time was two years unless reinfection occurred within this period. Univariable and multivariable logistic regression analyses were performed to identify the association between positive frozen sections and treatment failure., Results: Treatment failure occurred in eight (30.77%) of the 26 PJI patients with positive frozen sections at reimplantation, compared with 13 (9.49%) of 137 patients with negative results. In the multivariate analysis, positive frozen section increased the risk of failure (odds ratio 4.70; 95% confidence interval (CI) 1.64 to 13.45). The mean number of months to reinfection was lower in the positive frozen section group than in the control group (p = 0.041). While there were nine (34.62%) patients with positive frozen section and 25 (18.25%) patients with negative frozen section who had prolonged antibiotic use (p = 0.042), the mean duration of antibiotic use was comparable in two groups. Synovial white blood cell count (p = 0.137) and polymorphonuclear leucocyte percentage (p = 0.454) were not associated with treatment failure in logistic regression model., Conclusion: Positive frozen section at reimplantation was independently associated with subsequent failure and earlier reinfection, despite normal ESR and CRP levels pre-reimplantation. Surgeons should be aware of the risk of treatment failure in patients with positive frozen sections and carefully consider benefits of reimplantation. Cite this article: Bone Joint J  2021;103-B(5):916-922.

Background: Total hip arthroplasty (THA) can cause considerable blood loss and perioperative transfusion in ankylosing spondylitis (AS) patients. This study aimed to identify the factors related to blood loss in AS patients with hip involvement undergoing THA., Methods: We analyzed 243 AS patients with advanced hip involvement undergoing primary THA from 2012 to 2017. Bilateral THA was performed by a one-stage operation during one general anesthesia session. The patients were divided into three groups according to the grade of blood loss, as determined by the Advanced Trauma Life Support hypovolemic shock classification system. Ordinal logistic regression was used to identify factors associated with blood loss in the patients., Results: The proportion of patients who were male, underwent bilateral THA, had a hip range of motion (ROM) = 0°, had a BASRI-hip score of 4, underwent iliopsoas and adductor release, and underwent autologous or allogenic transfusion increased significantly with the grade of blood loss, while that of the patients who received tranexamic acid (TXA) decreased significantly (P < 0.05). The preoperative hemoglobin (Hb) level, hematocrit level, and operating time also increased significantly with the grade of blood loss (P < 0.05). The ordinal logistic regression results identified the factors related to blood loss during THA in AS patients with hip involvement to be the male sex (odds ratio [OR] = 3.287; 95% confidence interval [CI] 1.022, 10.567), bilateral THA (OR = 13.896; 95% CI 4.950, 39.011), hip ROM = 0° (OR = 2.513; 95% CI 1.277, 4.946), an elevated erythrocyte sedimentation rate (ESR) level (OR = 3.042; 95% CI 1.320, 7.014), an elevated preoperative Hb level (OR = 1.043; 95% CI 1.017, 1.070), a long operating time (OR = 1.009; 95% CI 1.003, 1.016), and the administration of TXA (OR = 0.252; 95% CI 0.134, 0.472)., Conclusions: The male sex, bilateral THA, a hip ROM = 0°, an elevated ESR level, a high preoperative Hb level, and a long operating time are risk factors associated with blood loss in AS patients with hip involvement undergoing THA, while the administration of TXA is a protective factor. These results might help determine the risk of bleeding in the perioperative assessment and develop more efficient blood management strategies for THA in AS patients with hip involvement.

Objective: To develop an artificial intelligence based three-dimensional (3D) preoperative planning system (AIHIP) for total hip arthroplasty (THA) and verify its accuracy by preliminary clinical application., Methods: The CT image database consisting of manually segmented CT image series was built up to train the independently developed deep learning neural network. The deep learning neural network and preoperative planning module were assembled within a visual interactive interface-AIHIP. After that, 60 patients (60 hips) with unilateral primary THA between March 2017 and May 2020 were enrolled and divided into two groups. The AIHIP system was applied in the trial group ( n =30) and the traditional acetate templating was applied in the control group ( n =30). There was no significant difference in age, gender, operative side, and Association Research Circulation Osseous (ARCO) grading between the two groups ( P >0.05). The coincidence rate, preoperative and postoperative leg length discrepancy, the difference of bilateral femoral offsets, the difference of bilateral combined offsets of two groups were compared to evaluate the accuracy and efficiency of the AIHIP system., Results: The preoperative plan by the AIHIP system was completely realized in 27 patients (90.0%) of the trial group and the acetate templating was completely realized in 17 patients (56.7%) of the control group for the cup, showing significant difference ( P <0.05). The preoperative plan by the AIHIP system was completely realized in 25 patients (83.3%) of the trial group and the acetate templating was completely realized in 16 patients (53.3%) of the control group for the stem, showing significant difference ( P <0.05). There was no significant difference in the difference of bilateral femoral offsets, the difference of bilateral combined offsets, and the leg length discrepancy between the two groups before operation ( P >0.05). The difference of bilateral combined offsets at immediate after operation was significantly less in the trial group than in the control group ( t =-2.070, P =0.044); but there was no significant difference in the difference of bilateral femoral offsets and the leg length discrepancy between the two groups ( P >0.05)., Conclusion: Compared with the traditional 2D preoperative plan, the 3D preoperative plan by the AIHIP system is more accurate and detailed, especially in demonstrating the actual anatomical structures. In this study, the working flow of this artificial intelligent preoperative system was illustrated for the first time and preliminarily applied in THA. However, its potential clinical value needs to be discovered by advanced research.

Background: The purpose of this study was to establish the finite element analysis (FEA) model of acetabular bone defect in Crowe type II or III developmental dysplasia of the hip (DDH), which could evaluate the stability of the acetabular cup with different types of bone defects, different diameters of femoral ceramic heads, and the use of screws and analyze the stress distribution of screws., Methods: The FEA model was based on the CT scan of a female patient without any acetabular bone defect. The model of acetabular bone defect in total hip arthroplasty for Crowe II or III DDH was made by the increasing superolateral bone defect area of the acetabular cup. Point A was located in the most medial part of the acetabular bone defect. A 52 mm PINNACLE cup with POROCOAT Porous coating was implanted, and two screws (the lengths were 25 mm and 40 mm) were implanted to fix the acetabular cup. The stability of the acetabular cup and the von Mises stress of point A and screws were analyzed by a single-legged stance loading applied in 1948 N (normal working). The different diameters of the femoral ceramic head (28 mm, 32 mm, and 36 mm) were also analyzed., Results: The von Mises stress of point A was gradually increased with the increasing uncoverage values. When the uncoverage values exceeded 24.5%, the von Mises stress of point A without screws increased significantly, leading to instability of the cup. Screws could effectively reduce the von Mises stress of point A with uncoverage values of more than 24.5%. However, the peak von Mises stress in the screws with the uncoverage values that exceeded 24.5% was considerably increased. The diameter of the femoral ceramic head had no significant effect on the von Mises stress and the stability of the acetabular cup., Conclusions: We recommend that uncoverage values of less than 24.5% with or without screw is safe for patients with Crowe II or III DDH., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2020 Yinqiao Du et al.)

Background: The impact of handedness on clinical outcomes was easily overlooked in hip replacement. This study aimed to find whether the component positioning and hip function were affected by the handedness in total hip arthroplasty (THA) through direct anterior approach (DAA)., Methods: Total 102 patients who underwent bilateral DAA-THAs simultaneously between May 2016 and November 2018 in our institute were reviewed. All surgeries were operated by one right-handed surgeon. Their demographic, cup positioning, stem alignment, femoral stem fit, Harris hip score (HHS), intraoperative and postoperative complications were used to evaluate the role of handedness in DAA., Results: The inclination of left cups was significantly larger than that of right cups (42.61 ± 7.32 vs 39.42 ± 7.19, p = 0.000). The stem fit of left femur was significantly larger than that of right femur (84.34 ± 4.83 vs 82.81 ± 6.07, p = 0.043). No significant differences in safe zone ratio, HHS and complications between bilateral hips were found., Conclusions: A surgeon's handedness had significant impact on cup's inclination and femoral stem fit in DAA-THA. However, there were no significant differences of cup malpositioning, stem alignment, hip function scores and complications between bilateral DAA-THAs.

Introduction: We aimed to explore the risk factors for periprosthetic joint infection (PJI) after primary artificial hip and knee joint replacements by performing a case-control study., Methodology: The clinical data of patients receiving primary hip and knee joint replacements were retrospectively analyzed. The case group included 96 patients who suffered from PJI, comprising 42 cases of hip joint replacement and 54 cases of knee joint replacement. Another 192 patients who received joint replacement at the ratio of 1:2 in the same period and did not suffer from PJI were selected as the control group. Differences between the two groups were compared in regard to etiology, pathogen, blood type, urine culture, body mass index (BMI), surgical time, intraoperative blood loss, postoperative 1st day and total drainage volumes, length of hospitalization stay, and history of surgery at the affected sites., Results: Gram-positive bacteria were the main pathogens for PJI. The most common infection after hip joint replacement was caused by Staphylococcus epidermidis, which accounted for 38.10%, while Staphylococcus aureus was mainly responsible for the infection of knee joint (40.74%). High BMI, long surgical time, large postoperative drainage volume, long hospitalization stay, history of surgery at incisions, previous use of immunosuppressants, preoperative hypoproteinemia and superficial infection were independent risk factors (p < 0.05)., Conclusions: PJI after primary replacement was mainly caused by gram-positive bacteria, and patients with high BMI, long surgical time, large postoperative drainage volume, long hospitalization stay, history of surgery at incisions, previous use of immunosuppressants, preoperative hypoproteinemia and superficial infection were more vulnerable., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2020 Heng Guo, Chi Xu, Jiying Chen.)

Objective: To investigate revision reasons and prosthesis selection of Crowe Ⅳ developmental dysplasia of the hip (DDH) after total hip arthroplasty (THA)., Methods: A clinical data of 14 patients (15 hips) with Crowe Ⅳ DDH, who underwent a revision hip arthroplasty between January 2008 and May 2018, was retrospectively reviewed. There were 1 male (1 hip) and 13 females (14 hips). The age ranged from 27 to 63 years (mean, 45.0 years). There were 7 cases of left hip, 6 cases of right hip, and 1 case of bilateral hips. The prosthetic interfaces of primary THA were metal-on-polyethylene (MOP) in 9 hips, ceramic-on-ceramic (COC) in 4 hips, ceramic-on-polyethylene (COP) in 1 hip, and ceramic-on-metal in 1 hip. The time from primary THA to revision was 3-204 months (mean, 65.0 months). The causes of revision included aseptic loosening in 7 hips, dislocation in 3 hips, periprosthetic joint infection in 2 hips, osteolysis in 1 hip, nonunion of osteotomy in 1 hip, and a small-angle of femoral anteversion in 1 hip. Preoperative Harris score was 54.1±17.8 and the range of motion (ROM) of flexion was (92.7±20.2)°. Preoperative X-ray films showed the acetabular bone defect in 11 hips and osteolysis of femoral side in 4 hips. During the revision, the prostheses with COP and COC interfaces were used in 5 hips and 10 hips, respectively. Both acetabular and femoral revisions were performed in 11 hips and only femoral revision was performed in 4 hips., Results: The mean operation time was 3.7 hours (range, 1.5-6.0 hours). The mean intraoperative blood loss was 940.0 mL (range, 200-2 000 mL). All patients were followed up 16-142 months (mean, 73.9 months). Postoperative X-ray films showed no difference in inclination and anteversion between primary THA and revision ( P >0.05). The height of rotation center and offset after revision were higher than those after primary THA, and the difference in offset was significant ( P <0.05). At last follow-up, the Harris score and ROM of flexion were 85.0±7.3 and (115.0±17.0)°, respectively, which were significantly higher when compared with those before revision ( t =8.909, P =0.000; t =4.911, P =0.000). Three hips underwent a re-revision operation. All protheses were fixed well and no radiolucent line, loosening, or subsidence was observed at last follow-up., Conclusion: The most common reason for revision in patients with Crowe Ⅳ DDH after THA was aseptic loosening. Due to high activity demand of this population, the prosthesis with MOP interface should be prevented and the prosthesis with COC interface could be alternative. Metal block, cup-cage, and reinforcement ring were reasonable solutions for reconstruction of acetabulum with severe bone defects and have satisfactory effectiveness. S-ROM prosthesis should be the preferred stem for neither primary THA or revision.

Background: Robot-assisted total hip arthroplasty (THA) has the potential of improving cup positioning. However, there is an associated learning curve with robot. This study aimed to determine one surgeon's learning curve with robot-assisted THA and whether robot could achieve similar accuracy in cup positioning as manual THA., Methods: The first 100 robot-assisted THA operated by one experienced surgeon on manual THA was respectively reviewed. The operating time and robotic complications were recorded to calculate the learning curve through cumulative summation analysis. The demographics, operating time, cup positioning, leg length discrepancy, hip offset, robotic complications and hip Harris score between proficient robot-assisted THA and manual THA in the same period were also compared., Results: The average operating time of robot-assisted THA was 95.92 ± 15.64 min, ranging from 68 to 145 min. Robot-assisted THA was associated with a learning curve of 14 cases for operating time. The duration of acetabular registration and cup implantation between two phases (1-14 and 15-100 case) had significant differences. There were 92% proficient robot-assisted THA and 82% manual THA respectively locating within the Lewinnek's safe zone. The variation of inclinations in proficient robot-assisted THA was significantly less than that in manual THA., Conclusion: In the surgeon's series, it took 14 cases' learning curve to be proficient in robot-assisted THA. In the proficiency phase, robot had an advantage in cup positioning than manual technique., Competing Interests: Declaration of competing interest None., (Copyright © 2020 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.)

Background: The purpose of this study was to examine whether surgeon handedness could affect cup positioning in manual total hip arthroplasty (THA), and whether robot could diminish or eliminate the impact of surgeon handedness on cup positioning in robot-assisted THA., Methods: Fifty-three patients who underwent bilateral robot-assisted THA and sixty-two patients who underwent bilateral manual THA between August 2018 and July 2019 in our institute were respectively analyzed in this study. When the difference between the bilateral anteversion and inclination was greater than 5°, the patient was regarded as having different cup positioning between bilateral THA. Their demographics, orientation of acetabular cup, and postoperative 3 month Harris hip score (HHS) were recorded for analysis., Results: There were no significant differences in the gender, age, BMI, diagnosis's composition, and preoperative and postoperative HHS between the robotic and manual group. Two left hips dislocated in the manual group. The anteversion of left hip was significantly larger than that of right hip (24.77 ± 10.44 vs 22.44 ± 8.67, p = 0.043) in the manual group. There were no significant differences of cup positioning between bilateral robot-assisted THA. The patients in manual group were significantly more likely to have different cup positioning between bilateral hips than those in robotic group (77% vs 45%, p = 0.000). More manual THA were located out of the target zone than robot-assisted THA (70% vs 48%, p = 0.001)., Conclusions: Surgeon's handedness showed a trend towards an impact on cup positioning in manual THA and robot might help surgeon eliminate the adverse impact. However, the impact of handedness on the clinical outcomes still needs further observation.

Background: We aimed to present our experience of adopting tissue adhesive as adjunct to standard wound closure in total hip arthroplasty (THA) and evaluate its performance., Methods: From September 2019 to November 2019, we prospectively enrolled consecutive patients who underwent simultaneous bilateral THA in this randomized and controlled study. Standard wound closure was applied on one side of hip while additional tissue adhesive was applied on the other side at random. We collected and analyzed patients' information, including age, gender, body mass index (BMI), diagnosis, postoperative length of stay (LOS), dressing changes, wound evaluation scores, wound-related cost and complications., Results: Thirty patients with simultaneous bilateral THA were enrolled in this study. During the hospital stay, the times of dressing change in hips with tissue adhesive was significantly less than that in the other hips (p = 0.000). However, the wound-related cost in hips with tissue adhesive was significantly higher (p = 0.000). According to patients' feedback at one-month follow-up, wound evaluation of hips with tissue adhesive was significantly better than the other hips (p = 0.004). Seventeen patients preferred tissue adhesive and only five patients preferred standard wound closure., Conclusions: Tissue adhesive could significantly reduce wound drainage and increase patients' satisfaction, which can be an ideal adjunct to standard wound closure in enhanced-recovery THA., Trial Registration: Chinese Clinical Trial Registry; ChiCTR1900025730; Registered 6 September 2019.

Background: Trochanter valgus deformity (TVD) is a rare condition of total hip arthroplasty (THA). Femoral osteotomy could be required in correcting the deformity to implant femoral stem in severe TVD. In this study, we described one unpublished technique of reverse sleeve of S-ROM to get through the complex situation. This study aimed to summarize and evaluate its technical challenges, safety and effectiveness., Methods: From January 2006 to December 2014, we enrolled patients whose sleeves were implanted towards the great trochanter in THA with TVD. Their demographics, perioperative and postoperative information were recorded. To explore its indication, we measured and analyzed the ratio of greater trochanter/lesser trochanter (G/L ratio) and trochanter valgus angle (TVA)., Results: Twelve patients (1 male and 11 female, average age 42.30 ± 10.23) had mean follow-up of 6 years. Among them, only two patients had intraoperative femoral fracture. The survivorship of femoral prosthesis was 100%. The Harris hip score (HHS) increased from preoperative 34.31 ± 14.43 to postoperative 84.12 ± 11.33. All patients' G/L ratio were larger than 1.50., Conclusions: The reverse sleeve of S-ROM was a reliable method for the patients with severe TVD, which brought satisfying clinical outcomes in mid-term follow-up.

Background: Diagnosing periprosthetic joint infection (PJI) requires various laboratory and clinical criteria. The purpose of this study was to explore novel biomarkers that could rapidly diagnose PJI with high accuracy., Methods: In this retrospective study of prospectively collected samples, 50 synovial fluid aspirates, 20 from the hip and 30 from the knee, were collected before surgery; 25 of the patients were diagnosed as having aseptic loosening (non-PJI) and 25, as having PJI according to the Musculoskeletal Infection Society criteria. A quadrupole orbital-trap mass spectrometry (MS) instrument was used to compare expression of proteins in patients with and without PJI. Proteins that were most efficacious for diagnosis of PJI were then determined using prediction analysis of microarray software and a random forest model. The most promising proteins were selected, and altered expression of these selected proteins was verified by ELISA (enzyme-linked immunosorbent assay) in an extended sample cohort., Results: A total of 256 proteins were significantly upregulated (≥3.0-fold) and 14 proteins were downregulated in synovial fluid of patients with PJI compared with patients without PJI. The 3 most promising proteins were lactoferrin (LTF), polymorphonuclear leukocyte serine protease 3 (PRTN3), and myeloid nuclear differentiation antigen (MNDA). When MS was used for diagnosis of PJI, the area under the curve was 0.9888 for LTF, 0.9488 for PRTN3, and 0.9632 for MNDA. ELISA results verified that LTF, MNDA, and PRTN3 were sensitive, while LTF and MNDA were specific, for diagnosis of PJI., Conclusions: This proteomic study identified a previously noted protein and 2 novel candidate proteins as promising synovial fluid biomarkers for PJI diagnosis, and they should be further validated in future clinical trials., Level of Evidence: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Objective: To investigate the accuracy of preoperative digital-template planning in total hip arthroplasty (THA) via direct anterior approach (DAA) and its effect on the short-term effectiveness., Methods: The clinical data of 77 patients (109 hips) with osteonecrosis of femoral head who underwent THA via DAA between January 2016 and May 2018 was retrospectively analyzed. According to the type of template, patients were divided into digital-template group (group A, 40 patients, 56 hips) and conventional-template group (group B, 37 patients, 53 hips). There was no significant difference in age, gender, body mass index, the stages of osteonecrosis of femoral head, and preoperative Harris hip score (HHS) ( P >0.05). The operation time, intraoperative blood loss, frequencies of intraoperative fluoroscopy, and complications were recorded. Otherwise, the consistency rate of preoperative planning and practical prosthesis size was analyzed. Position of acetabular prosthesis and femoral prosthesis alignment were measured on anteroposterior X-ray film of the pelvis at 3 months after operation. HHS was used to evaluate clinical function., Results: The consistency rate of preoperative planning and practical acetabular prosthesis size was significantly higher in group A (80.4%, 45/56) than that in group B (62.3%, 33/53), showing significant difference ( χ 2 =4.38, P =0.04). But there was no significant difference in the consistency rate of preoperative planning and practical femoral prosthesis size between group A (83.9%, 47/56) and group B (79.2%, 42/53）( χ 2 =0.40, P =0.53). The prosthesis abductions were (40.7±6.4)° in group A and (38.8±7.3)° in group B; the femoral prosthesis alignment deviations were (0.1±1.8)° in group A and (0.3±1.7)° in group B. There was no significant difference in the prosthesis abduction and femoral prosthesis alignment deviation between 2 groups ( P >0.05). No prosthesis sinking or loosening occurred during follow-up. The operation time and frequencies of intraoperative fluoroscopy were less in group A than those in group B ( P <0.05). But there was no significant difference in intraoperative blood loss between 2 groups ( t =1.92, P =0.06). The complication occurred in 1 hip of group A and 6 hips of group B, with no significant difference ( P =0.06). All patients were followed up 6-22 months (mean 13.8 months) in group A and 6-24 months (mean, 14.6 months) in group B. At last follow-up, the HHS scores were 91.8±3.1 in group A and 92.6±4.2 in group B, and the difference was not significant ( t =1.14, P =0.26)., Conclusion: Preoperative digital-template planning in THA via DAA is accurate, which can reduce the operation time and frequencies of intraoperative fluoroscopy without enhancing the risk of complication.

Background: The variation of femoral anteversion is not completely consistent with the grade of developmental dysplasia of the hip (DDH), which poses challenges to hip replacement with the non-modular tapered stem. Currently, whether the modular stem should be used in Crowe I and II DDH is still controversial. The aim of this study is to compare the clinical efficacy of the modular stem and the non-modular tapered stem in Crowe I and II DDH patients., Methods: We retrospective analyzed the clinical data of 196 patients with unilateral Crowe I and II DDH from January 2015 to January 2017. One hundred patients were operated by an experienced surgeon with the modular stems; the remaining 96 patient was operated by another equivalent surgeon with the non-modular tapered stems. The preoperative basic information, operating time, intraoperative and postoperative complications, postoperative leg length discrepancy (LLD) and offset, Harris hip score (HHS), and forgotten joint score (FJS) in postoperative 2 years were collected and analyzed., Results: Postoperative LLD (P = 0.010) and FJS (P = 0.001) had significant difference between two groups. Concurrent acceptable LLD and offset were achieved in 87% of patients with the modular stem and in 68% of patients with the non-modular stem (P = 0.001). There was no significant difference in the operating time (P = 0.086), intraoperative complication (P = 0.096), postoperative dislocation rate (P = 0.056), postoperative offset difference (P = 0.108), and Harris score (P = 0.877) between two groups., Conclusions: Compared with the non-modular tapered stem, the modular stem was more likely to provide accurate reconstruction and forgotten artificial hip for Crowe I and II DDH patients. We recommend the modular stem as routine choice for these patients.

Background: Limb length discrepancy (LLD) is one of the main cause of dissatisfaction after total hip arthroplasty (THA). The teardrop-lesser trochanter method can accurately predict and analyze LLD for healthy people. However, for patients with preoperative LLD, no method for predicting postoperative LLD is currently available, and these patients are highly susceptible to more severe LLD after THA. Accordingly, this study proposed a calculation method to predict postoperative limb length for these patients., Methods: Eighty patients who underwent THA between May 2016 and October 2018 due to unilateral developmental dysplasia of the hip (DDH) were evaluated. Relevant parameters were measured from radiographs of full-length lower limbs, e.g. the distance between the rotation center of the hip and the midpoint of the tibial plafond and the distance between the point which was marked at the same height as the lesser trochanter on the anatomical long axis of the femur and the midpoint of the tibial plafond. Then, a mathematical model was established by simplifying the structure from the hip to the ankle. The relationship between the placement position of the prosthesis and the LLD value was calculated by Law of Sines and Iterative Calculation., Results: The preoperatively predicted LLD values and the postoperatively measured LLD values were compared, yielding a mean absolute difference of 3.7 (range, 0.1 to 8.6) mm. The intraclass correlation coefficient (ICC) of the two parameters exhibited strong reliability (ICC = 0.911, 95%CI, 0.795 to 0.955). The Bland-Altman plot also showed good conformity between the two parameters., Conclusions: The proposed calculation method effectively predicted the postoperative LLD using preoperative parameters. Despite the complexity of the method, it can go a long way towards reducing the occurrence of severe postoperative LLD in DDH-THA.

Aims: This study aimed to explore whether intraoperative nerve monitoring can identify risk factors and reduce the incidence of nerve injury in patients with high-riding developmental dysplasia., Patients and Methods: We conducted a historical controlled study of patients with unilateral Crowe IV developmental dysplasia of the hip (DDH). Between October 2016 and October 2017, intraoperative nerve monitoring of the femoral and sciatic nerves was applied in total hip arthroplasty (THA). A neuromonitoring technician was employed to monitor nerve function and inform the surgeon of ongoing changes in a timely manner. Patients who did not have intraoperative nerve monitoring between September 2015 and October 2016 were selected as the control group. All the surgeries were performed by one surgeon. Demographics and clinical data were analyzed. A total of 35 patients in the monitoring group (ten male, 25 female; mean age 37.1 years (20 to 46)) and 56 patients in the control group (13 male, 43 female; mean age 37.9 years (23 to 52)) were enrolled. The mean follow-up of all patients was 13.1 months (10 to 15)., Results: The two groups had no significant differences in preoperative data. In the monitoring group, ten nerve alerts occurred intraoperatively, and no neural complications were detected postoperatively. In the control group, six patients had neural complications. The rate of nerve injury was lower in the monitoring group than in the control group, but this did not achieve statistical significance. The degree of leg lengthening was significantly greater in the monitoring group than in the control group. In further analyses, patients who had previous hip surgery were more likely to have intraoperative nerve alerts and postoperative nerve injury., Conclusion: Nerve injury usually occurred during the processes of exposure and reduction. The use of intraoperative nerve monitoring showed a trend towards reduced nerve injury in THA for Crowe IV DDH patients. Hence, we recommend its routine use in patients undergoing leg lengthening, especially in those with previous hip surgery. Cite this article: Bone Joint J 2019;101-B:1438-1446.

Background: Periprosthetic joint infection (PJI) is a devastating complication following total joint arthroplasty (TJA). Now, the definition of PJI traditionally used in clinical practice was set out by the International Consensus Meeting (ICM) and Infectious Diseases Society (IDSA). There was a new definition proposed in May 2018 on a paper published in the Journal of Arthroplasty. The new scoring system for PJI demonstrated a higher sensitivity and specificity than Musculoskeletal Infection Society and IDSA criteria. Therefore, we wanted to find further evidence to support the new definition in the Chinese population., Methods: The patients who were included in our study were divided into PJI group and aseptic group. Medical records of patients (98 in PJI group and 165 in aseptic group) were reviewed, and the score of every patient was aggregated based on the new definition and collected data. The sensitivity and specificity were compared between new definition and classical criteria., Results: For patients in our hospital, the overall sensitivity and specificity of the new criteria were respectively 94.9% (95% confidence interval [CI] 87.9-98.1%) and 95.2% (95% CI 90.3-97.7%). The new definition demonstrated a higher sensitivity than traditional criteria in Chinese population, and the specificity was similar to existing criteria., Conclusion: We believe the new scoring system about periprosthetic joint infection could also apply to Chinese population for diagnosing PJI following TJA. It can obviously improve diagnostic efficiency for PJI compared with traditional criteria.

Introduction: Sexual activity is often an important component of life. To date, no studies have examined sexual activity before and after total hip arthroplasty (THA) in male patients with ankylosing spondylitis (AS). The purpose of the current study was to evaluate the effect of THA on sexual activity and to explore the most commonly reported and comfortable coital position for male AS patients with hip involvement., Methods: Data from 31 male AS patients who underwent THA for hip involvement were retrospectively reviewed. Information from the International Index of Erectile Function (IIEF), the Harris Hip Score (HHS) and other clinical parameters was collected and monitored over time. We compared the above-mentioned parameters before surgery and 2 years after surgery and analysed the correlation between changes on the IIEF and changes in clinical parameters., Results: The domain and total scores of the IIEF, except EF, were significantly higher after surgery than were those before surgery ( p < 0.05). There was a significant positive correlation between changes on the IIEF and improvement in flexion-extension range of motion (ROM), adduction-abduction ROM and HHS ( p < 0.05). Most patients (26/31, 83.9%) resumed sexual activity 5-12 weeks after surgery. The pre- and postoperative distributions of the most commonly reported and comfortable position were not significantly different (p > 0.05)., Conclusions: Successful THA may improve sexual activity in male AS patients with hip involvement. Changes in hip ROM show the most significant correlation with improvement in sexual activity. Resumption of sexual activity occurs within 5-12 postoperative weeks.

This study aimed to compare the accuracy of pelvic height planning vs. the conventional templating method for acetabulum cup measurement. A total of 200 consecutive patients undergoing primary total hip arthroplasty (THA) were randomly grouped as follows: group A, accepting conventional templating; group B, accepting pelvic height planning. Preoperative measurement of the acetabular cup was performed with conventional templating and pelvic height planning, respectively. There were 57 cases with the same size or with one type size discrepancy, 49 with two type size discrepancies, and 14 with three type size discrepancies in group A. There were 145 cases with the same size or one type size discrepancy, 20 with two type size discrepancies, and 3 type size discrepancies in group B. The mean difference between the planned size and actual cup size was 2.58 ± 0.89 mm (group A) vs. 1.38 ± 1.22 mm (group B). Therefore, pelvic height planning is reliable for use in preoperative planning compared with conventional templating.

Objective: To investigate the mid-term effectiveness of debridement with prosthesis retention for periprosthetic joint infection (PJI) after total hip arthroplasty (THA) and total knee arthroplasty (TKA), and analyze the influence factors that affected the effectiveness., Methods: A clinical data of 45 cases with PJI after THA (16 cases) and TKA (29 cases) that were treated with debridement with prosthesis retention between January 2011 and January 2015 were collected and analyzed. There were 19 males and 26 females with a mean age of 58.4 years (range, 23-78 years). PJI occurred after primary joint arthroplasty in 40 cases and after revision in 5 cases. The mean time interval between the performance of infection symptoms and the arthroplasty or revision was 15.5 months (range, 0.5-72.0 months). The time interval between the performance of infection symptoms and debridment was 35 days (range, 3-270 days). There were early postoperative infections in 13 cases, acute hematogenous infections in 24 cases, and late chronic infections in 8 cases. X-ray films showed that the location of prosthesis was good. The results of bacilli culture showed that 28 cases were positive and 17 were negative. Twelve cases had sinuses. Length of stay, Hospital for Special Surgery (HSS) score, and Harris score were recorded to evaluate risk factors by using a multivariate logistic regression., Results: The mean length of stay was 22.6 days (range, 5-79 days). All patients were followed up 24-74 months (mean, 52 months). There were 33 cases that retained the prosthesis without further evidence of infection with the success rate was 73.3%. There were significant differences in Harris score and HSS score between pre- and post-operation ( P <0.05). The univariate analysis results showed that the failure of debridement with prosthesis retention had a significant correlation with sinus developing and duration of infection symptoms more than 14 days ( P <0.05). Multivariate logistic regression analysis results showed that sinus developing was an independent risk factor of failure ( P <0.05)., Conclusion: Debridement with prosthesis retention plays an important role in treating PJI after THA and TKA. These patients with sinus performing and duration of infection symptoms more than 14 days have higher risk to develop infection again.

Background: The impact of surgeon handedness on acetabular cup orientation in total hip arthroplasty (THA) is not well studied. The aim of our study is to investigate the difference of cup orientation in bilateral THA performed by right-handed surgeons using posterolateral approach and which cup could be fitter to Lewinneck's safe zone., Methods: The study consisted of 498 patients that underwent bilateral THA by three right-handed surgeons in our hospital. Postoperative acetabular cup anteversion and abduction on an anteroposterior pelvic radiograph were measured by Orthoview software (Orthoview LLC, Jacksonville, Florida). Furthermore, the percentage of cup placement within the safe zone was compared., Results: The mean anteversion was 25.28 (25.28° ± 7.16°) in left THA and 22.01 (22.01° ± 6.35°) in right THA (p < 0.001). The mean abduction was 37.50 (37.50° ± 6.76°) in left THA and 38.59 (38.59° ± 6.84°) in right THA (p = 0.011). In the left side, the cup was positioned in Lewinnek's safe zone in 52% for anteversion, 87% for abduction, and 46% for both anteversion and abduction. But the cup placement within Lewinnek's safe zone was 71, 88, and 62% in the right side, respectively. There were significant differences in the percentage of acetabular cup placement within the safe zone for anteversion (p < 0.001) and for both anteversion and inclination (p < 0.001). Dislocation occurred in 7.0% (35/498) of cases in left THA and 3.2% (16/498) in right THA. The percentages of patients experiencing dislocation were significantly different between the two sides (p = 0.006)., Conclusions: This current study demonstrated that surgeon handedness is likely to be a contributing factor that affects cup inclination and anteversion in bilateral THA and that the placement of cup performed by dominant hands of surgeons is more accurate than that performed by non-dominant sides.

Objective: To study the imaging features of the hip joint by measuring the imaging parameters of spine, pelvis, and hip joint before and after total hip arthroplasty (THA) in patients with ankylosing spondylitis (AS) undergoing THA so as to provide reference for selection of operation methods and prosthesis., Methods: Between January and July 2015, 38 patients (56 hips) with AS underwent primary THA as AS group, and 36 patients (45 hips) with osteonecrosis of the femoral head underwent THA as control group. There was no significant difference in side ( χ 2 =1.14, P =0.95). The acetabular abduction angle (ABA), acetabular anteversion angle (AVA), center collum diaphyseal (CCD), offset, height from rotation center to lesser trochanter (HRCLT), femoral intertrochanteric distance (FID) were measured by CT three-dimensional morphology. The canal flare index (CFI), cortical thickness index (CTI), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) were measured by X-ray film before operation. The AVA, ABA, and the filling ratio were measured on the postoperative X-ray film., Results: There was no significant difference in preoperative AVA and ABA and postoperative ABA between 2 groups ( P >0.05), but significant difference was found in postoperative AVA ( t =6.71, P =0.00). The mean PI, SS, and PT in AS group were 48.37° (range, 41-58°), 5.64°(range, 2-11°), and 12.85° (range, 5-26°), respectively. There was significant difference in CCD, CFI, and CTI between 2 groups ( t =3.63, P =0.04; t =5.12, P =0.02; t =3.91, P =0.04), but offset, HRCLT, and FID all showed no significant difference ( t =0.41, P =0.36; t =0.33, P =0.56; t =0.59, P =0.12). On the basis of the Noble classification, medullary cavity of the femur was rated as chimney type, ordinary type, and champagne flute type in 32, 18, and 6 hips of AS group, and in 4, 28, and 13 hips of control group respectively. Filling ratio of distal segment in AS group was significantly lower than that in control group ( t =5.64, P =0.02), but there was no significant difference in the filling ratio of middle and proximal segments between 2 groups ( t =0.29, P =0.61; t =0.55, P =0.13)., Conclusion: Compared with patients having osteonecrosis of the femeral head, there is no significant difference in preoperative AVA and ABA, but postoperative AVA significantly increase in patients with AS. Because AS patients have mainly chimney type medullary cavity of the femur, the filling ratio of middle and distal segment is lower when tapered stems are used, and the filling ratio of anatomic stems is higher.

Periprosthetic femoral fracture (PFF) is a complicated complication of both primary and revision hip arthroplasty with an increasing incidence. The present study aimed to summarize the clinical characteristics and identify the risk factors for PFF which would be potentially helpful in the prevention and treatment of PFF.We retrospectively analyzed the clinical data of 89 cases of PFF, and a case-control study was designed to identify the potential risk for intraoperative and postoperative PFF in both primary and revision hip arthroplasty.The overall incidence of PFF was 2.08% (intraoperative: 1.77%, postoperative: 0.30%, revision: 13.60%, and primary: 0.97%). The most commonly used treatment strategy was fixation with cerclage wire or band for intraoperative PFF, whereas long stem revision with plate or cortical allograft strut fixation was the main treatment strategy for postoperative PFF. The risk factors for intraoperative PFF in primary total hip arthroplasty (THA) included the diagnosis of development dysplasia of the hip (DDH) (odds ratio [OR] = 5.01, 95%CI, 1.218-20.563, P=0.03) and CBR ≥ 0.49 (OR = 3.34, 95%CI, 1.138-9.784, P = 0.03). The increased age was associated with increased incidence of postoperative PFF in primary THA (OR = 1.09, 95%CI, 1.001-1.194, P = 0.04). As for the intraoperative PFF in revision THA, we found that receiving multiple operations before revision (OR = 2.45, 95%CI, 1.06-5.66, P = 0.04), revisions due to prosthetic joint infection (OR = 6.72, 95%CI, 1.007-44.832, P = 0.04), the presence of cementless implant before revision (OR = 13.54, 95%CI, 3.103-59.08, P = 0.001), and femoral deformity (OR = 8.03, 95%CI, 1.656-38.966, P = 0.01) were all risk factors.Screening for high-risk patients, preoperative templating, and detailed discharge instructions may be the potential strategies to reduce the incidence of PFF. The treatment of PFFs should take into account Vancouver classification system, patient's characteristics as well as the experience of the operating surgeon., Competing Interests: The authors have no conflicts of interest to disclose.

Objective: To evaluate the inflammatory markers in patients with ankylosing spondylitis (AS) or non-inflammatory diseases undergoing total hip arthroplasty (THA) and to ascertain the variation trend of perioperative inflammatory markers and the influence of inflammation markers after THA., Methods: Between January 2013 and December 2014, 153 consecutive patients with AS were included. According to the range of motion (ROM), the patients were divided into ankylosis group (ROM: 0 degrees; group A, n = 92) and stiff group (ROM: 3-46 degrees; group B, n = 61); 120 non-inflammatory diseases patients having no bacterial infection and undergoing primary THA served as non-inflammatory group (group C). The inflammatory markers including C-reactive protein (CRP), interleukin-6 (IL-6), and erythrocyte sedimentation rate (ESR) concentrations were measured before operation and at 1, 3, 5, and 7 days after operation, and the complication was observed., Results: Perioperative serum CRP, IL-6, and ESR increased at first after operation, and then decreased in 3 groups. There were significant differences in CRP and ESR between at pre- and post-operation (P < 0.05); the IL-6 at 1, 3, and 5 days after operation were significantly higher than that at preoperation (P<0.05), but no significant difference was found between at 7 days and at preoperation (P > 0.05). CRP, IL-6, and ESR of group B were significantly higher than those of group A at preoperation (P < 0.05); CRP and IL-6 of groups A and B were significantly higher than those of group C at preoperation and at 1 day after operation (P < 0.05); ESR of groups A and B was significantly higher than that of group C at preoperation, and at 1 day and 3 days after operation (P < 0.05); and no significant difference was shown among 3 groups at the other time points (P > 0.05). No inflammatory activity or increased complication was observed., Conclusion: AS and non-inflammatory diseases show similar change trend of inflammatory markers at pre- and post-operation. The inflammatory activity of AS has no significant effect on the changes of inflammation markers and does not increase the incidence of postoperative complications.

Objective: To investigate the clinical characteristic differences of cementless total hip arthroplasty (THA) between with and without subtrochanteric femoral shortening osteostomy in Crowe type IV developmental dysplasia of the hip (DDH)., Methods: Between January 2006 and March 2012, 21 patients (21 hips) with Crowe type IV DDH who underwent primary THA were enrolled according to inclusion criteria. According to whether subtrochanteric femoral shortening osteostomy was performed during THA or not, the patients were divided into 2 groups: THA with osteostomy group (n = 9) and THA without osteotomy group (n = 12). There was no significant difference in gender, age, body mass index, and hip Harris score between 2 groups (P > 0.05) except leg length discrepancy (t = -3.170, P = 0.005). The operation time, blood loss, postoperative drainage, complications, and radiography data were compared to evaluate the clinical characteristics., Results: The operation time, blood loss, and postoperative drainage of osteotomy group were all significantly greater than those of no osteotomy group (P < 0.05). All patients achieved primary healing of incision; 1 patient (1 hip) had transient sciatic nerve symptom in osteotomy group. The average follow-up time was 53 months (range, 28-88 months). The X-ray films showed good fracture healing at 3-6 months after operation in osteostomy group. No prosthetic loosening or dislocation was found. The hip Harris score was 90.67 ± 4.06 in osteostomy group and 92.17 ± 3.27 in no osteostomy group, showing no significant difference between 2 groups (t = -0.938, P = 0.360). The leg length discrepancy was (0.22 ± 0.26) cm in osteostomy group and (0.18 ± 0.27) cm in no osteostomy group, showing no significant.difference (t = 107.000, P = 0.546). The leg length discrepancy was found in 6 patients of osteotomy group and 5 patients of no osteotomy group. One patient complained of thigh pain in osteotomy group; 2 patients had slight limp (Trendelenburg +) in no osteotomy group., Conclusion: THA can improve joint function and increase limb length in the treatment of Crowe type IV DDH. Subtrochanteric shortening osteotomy is an effective treatment which can be performed according to preoperative template measurement, leg length shortening, and the soft tissue tension.

Objective: To explore the clinical characters and histopathologic differences between patients with culture-positive and culture-negative prosthetic joint infection (PJI)., Methods: Between January 2012 and July 2013, 66 PJI patients in accord with diagnostic criteria were enrolled. According to the results of preoperative aspiration and intraoperative cultures, the patients were divided into culture-negative group (CN group, n = 21) and culture-positive group (CP group, n = 45). There was no significant difference in gender, age, height, weight, and body mass index between 2 groups (P > 0.05). Preoperative C reactive protein (CRP), erythrocyte sedimentation rate (ESR), and prosthesis survival time were compared between 2 groups. Intraoperative frozen sections and paraffin sections were both performed to identify infections, and histological typing was performed according to Morawietz's methods., Results: The preoperative CRP was (1.29 +/- 1.84) mg/dL in CN group and (5.08 +/- 9.57) mg/dL in CP group, showing significant difference (t = 2.094, P = 0.038). The preoperative ESR was (22.86 +/- 28.42) mm/1 h in CN group and (36.74 +/- 31.26) mm/1 h in CP group, showing significant difference (t = 7.761, P = 0.000). The median survival time of prosthesis was 72 months (range, 8-504 months) in CN group and 25 months (range, 15 days-300 months) in CP group, showing significant difference (U = 2.231, P = 0.026). Morawietz's histological typing results showed that 2 cases were rated as type I, 7 cases as type II, and 12 cases as type III in CN group; 6 cases were rated as type I, 25 cases as type II, 13 cases as type III, and 1 case as type IV in CP group. The positive culture rate was 68.18% (45/66), and pathogenic bacteria was dominated by Staphylococcus, accounting for 68.89%., Conclusion: The patients with culture-negative PJI have slow onset and mild inflammatory response, so comprehensive diagnosis should be made based on pathological detection, laboratory examination, and intraoperative cultures.

Objective: To investigate the effectiveness of total hip arthroplasty with double-tapered cementless femoral stem for hip bony fusion by comparing with anatomical cementless femoral stem., Methods: A retrospective analysis was made on clinical data of 50 cases (80 hips) of hip bony fusion undergoing total hip arthroplasty between October 1999 and January 2008. The patients were divided into 2 groups: 31 cases (49 hips) using BetaCone double-tapered cementless femoral stem (trial group), and 19 cases (31 hips) using Ribbed anatomical cementless femoral stem (control group). There was no significant difference in gender, age, disease duration, preoperative Harris score, and abduction angle of the hip between 2 groups (P > 0.05). After operation, X-ray films were used to calculate the ratio of force arm of abductor (a) to the force arm of gravity (b) and analyze the stability of the prosthesis. The abduction angle of the hip and Harris score were measured during follow-up., Results: Fracture occurred during operation in 9 hips of 9 cases (5 in trial group and 4 in control group), and was cured after fixation. The mean follow-up time was 49 months (range, 12-98 months) in trial group and was 53 months (range, 6-105 months) in control group. The ratio of a/b was 0.65 +/- 0.25 in trial group and was 0.56 +/- 0.37 in control group, showing significant difference (t = 2.19, P = 0.03). The abduction angle of hip was (34.49 +/- 7.58) degrees in trial group and was (30.97 +/- 7.24) degrees in control group at 6 months after operation, which was significantly improved when compared with preoperative value in 2 groups (P < 0.05), and significant difference was found between 2 groups (t = 2.06, P = 0.04). Postoperative Harris score was significantly improved in 2 groups when compared with preoperative score (P < 0.05); trial group was better than control group in Harris score at 1 month after operation (t = 3.62, P = 0.01), but no significant difference was found between 2 groups at last follow-up (t = 1.61, P = 0.11). At last follow-up, X-ray films showed stabilized prosthesis in 2 groups. Grade I or II ectopic ossification occurred in 12 cases (14 hips) of trial group and 8 cases (9 hips) of control group at 2 years after operation., Conclusion: The total hip arthroplasty with both double-tapered and anatomical cementless femoral stems for hip bony fusion can obtain satisfactory effectiveness, while the double-tapered cementless femoral stem has better abduction angle of hip.

Background: Most patients with displaced femoral neck fractures are treated by THA and hemiarthroplasty, but it remains uncertain which if either is associated with better function and lower risks of complications., Questions/purposes: We performed a meta-analysis of randomized controlled trials (RCTs) to determine whether THA was associated with lower rates of reoperations, mortality, complications, and better function compared with hemiarthroplasty., Methods: We searched the PubMed, Embase, Chinese Biomedicine Literature, and Cochrane Register of Controlled Trials databases and identified 12 RCTs (including a total of 1320 patients) for meta-analysis. Risk ratios (RRs) and weighted mean differences (WMDs) from each trial were pooled using random-effects or fixed-effects models depending on the heterogeneity of the included studies., Results: THA was associated with a lower risk of subsequent reoperations compared with hemiarthroplasty (RR = 0.53; 95% CI, 0.34-0.84). There was no difference in mortality between patients undergoing THA and hemiarthroplasty (RR = 0.81; 95% CI, 0.60-1.09). For complications, there was a higher risk of dislocation in patients undergoing THA (RR = 1.99; 95% CI, 1.26-3.15), but there were no differences in local infections (RR = 1.60; 95% CI, 0.74-3.46) and general complications (RR = 1.15; 95% CI, 0.91-1.45). Patients with THA had higher Harris hip scores at 1 year (WMD = 3.81; 95% CI, 0.87-6.74) and at 3 or 4 years (WMD = 10.07; 95% CI, 6.92-13.21)., Conclusions: Despite more dislocations, THA can benefit patients with displaced femoral neck fractures with a lower reoperation rate and higher functional scores.