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Abstract Background Patients with simultaneous ruptures of the patellar tendon (PT) and anterior cruciate ligament (ACL) underwent PT repair and ACL reconstruction in a single or staged surgery. However, due to the limited cases, the design of previous studies was mostly case report with varying conclusions regarding recommended surgical strategy selection, the optimal surgical strategy remains a subject of debate. Methods We conducted a retrospective case series and literature review, including 10 cases from local institution and 27 cases from 17 studies. Demographic information, injury causes, surgical strategies, combined injuries, whether to return to (pre-injury level) sports, postoperative complications, Lysholm score and International Knee Documentation Committee (IKDC) score were identified retrospectively or reviewed from previous studies. The Fisher’s exact test was used to compare the incidence of postoperative complications between different surgical strategy groups, and linear logistic regression was used to analyze factors influencing postoperative knee function scores. Results Of the 37 patients, 15 patients (40.5%) underwent single surgery and 22 patients (59.5%) underwent staged surgery. Postoperative complications occurred in 5 (33.3%) patients after single surgery and in none after staged surgery, with the former being significantly more frequent than the latter (P = 0.007). Linear regression of postoperative knee function scores showed that surgical strategy did not significantly affect postoperative Lysholm and IKDC scores (P = 0.327 and P = 0.348, respectively). Conclusions This study demonstrates that staged surgery significantly reduces postoperative complications compared to single surgery in patients with simultaneous PT and ACL ruptures and should be considered the preferred approach, especially when an expedited return to sports is not a priority.

Abstract Background The healing and remodeling process of tendon grafts after anterior cruciate ligament (ACL) reconstruction (ACLR) has received significant attention. This study aims to identify preoperative factors associated with postoperative signal intensity of the ACL graft after primary ACLR. Methods A total of 90 patients underwent primary ACLR using hamstring tendon autografts by the same senior surgeon between January 2013 and December 2020 were included. Patients were followed up and scheduled for a 2-year postoperative magnetic resonance imaging (MRI) scan at our institute. Concomitant injuries were confirmed by arthroscopy. Posterior tibial slope (PTS) and anterior tibial subluxation (ATS) were measured on preoperative MRI, whereas the normalized signal intensity of the ACL graft was evaluated on postoperative MRI and calculated as the ratio of the graft signal intensity to that of the patellar tendon. Multivariable linear regression models were performed to identify preoperative factors associated with the postoperative signal intensity of the ACL graft. Results Multivariable analyses showed that increased global PTS (GPTS) (P = 0.008) and concomitant articular cartilage injuries (P = 0.005) were associated with higher average signal intensity of the ACL graft on two-year postoperative MRI, while preoperative internal rotational tibial subluxation (IRTS) calculated as the difference between lateral ATS and medial ATS did not show a significant association. Specifically, an increased GPTS was significantly associated with higher signal intensity in the proximal section of the ACL graft (P = 0.005), whereas no significant associations were observed in the middle and distal sections. Conclusions Increased preoperative GPTS was significantly associated with higher signal intensity of the ACL graft on 2-year postoperative MRI after primary ACLR, suggesting that a steep preoperative tibial slope may contribute to a suboptimal ligamentization process in hamstring tendon autografts. Level of evidence Level III, retrospective cohort study.

With the development of society, the incidence of myopia and the population of myopia has increased year by year, which has become a major public health problem. Therefore, the research on the pathogenesis and prevention and control measures of myopia is imminent. In recent years, the role of the biological clock in the development of myopia has gradually attracted scholars interest. Now the author starts from the impact of the biological clock on the axial length, retina and choroid in the development of myopia. In order to provide new ideas for the study of prevention and control measures and the pathogenesis of myopia, a brief review is made from the perspective of contemporary society and disrupted body clock.

Abstract Background The association between chronic anterior cruciate ligament (ACL) injury and inferior postoperative outcomes following ACL reconstruction (ACLR) has been highlighted in the literature. However, the inclusion of postoperative radiological assessments in previous studies has been limited. The aim of this study is to investigate whether chronic ACL injury is associated with an inferior tibiofemoral position measured on magnetic resonance (MR) images after primary ACLR. Methods A total of 62 patients that underwent primary ACLR were included in this study based on the time from injury to surgery, namely the acute ACL-injured group (within 6 weeks) and the chronic ACL-injured group (more than 1 year) and were matched 1:1 according to sex, age (± 2 years), and time from surgery to follow-up (± 3 months). Patient demographics, surgical records and follow-up data were retrieved and analyzed. The altered tibiofemoral position was measured quantitatively on preoperative and at least 1-year postoperative MR images and compared between the two groups, including the lateral, medial and global anterior tibial subluxation (LATS, MATS and GATS) and internal rotational tibial subluxation (IRTS). Results No significant differences in preoperative LATS, MATS, GATS or IRTS were identified between the acute and chronic ACL-injured groups. The chronic ACL-injured patients showed significantly increased postoperative MATS (p = 0.001) and GATS (p = 0.012), while no significant difference was identified in postoperative LATS or IRTS. Multivariate linear regression analyses showed that chronic ACL injury resulted in an estimated increase of 2.0 mm in postoperative MATS (p = 0.012) and 1.9 mm in postoperative GATS (p = 0.040). A significant improvement in postoperative LATS was observed in the acute ACL-injured group (p = 0.044) compared to preoperative LATS, while no improvements in these MRI measurements were observed in the chronic ACL-injured group. Conclusion Chronic ACL-injured patients showed increased MATS and GATS measured on 1-year postoperative MR images after primary single-bundle ACL reconstruction, while no difference was identified in rotational tibiofemoral position. The acute ACL-injured group demonstrated a significant improvement in postoperative LATS, whereas no improvements were observed in the chronic ACL-injured group. Level of evidence Level III.

Based on a summary of the characteristics of the industrial Internet, combined with the overall status of the existing industrial Internet, this paper analyzes the problems of the traditional industrial automation closed five-tier architecture and concludes that the current industrial Internet remains in a stage of technological development and maturation, which restricts the promotion and standardization of China’s intelligent manufacturing level to some extent. In the future, the industrial Internet will break the original data hierarchy structure, break the data barrier, and realize the development of intelligent manufacturing toward intelligent, flattening, lightweight, and green. First, this paper proposes a new industrial network collaboration architecture on the cloud side that supports efficient data flow. The proposed architecture is a flat, platform-based structure that realizes cloud-side collaboration and the integration of control, computing power, and network. Second, on the basis of the overall architecture of the industrial network, two key technologies are proposed to adapt the new industrial network infrastructure. One is 5G–time-sensitive networking (TSN) collaborative transmission technology. TSN realizes the interconnection and integration of heterogeneous networks in the industrial field based on the data link layer, and 5G–TSN collaborative transmission has become an important evolution trend of the intelligent factory network. Three key technical contents are introduced: 5G–TSN heterogeneous network convergence architecture, network clock adaptation mechanism, and software defined network (SDN)-based integration management and resource scheduling. The other key technology is cloud PLC technology based on a deterministic network, and the virtualization and cloud control system is the basis for breaking the original closed industrial control system. On the one hand, cloud-based hardware resources can be used to achieve one-to-many control, saving a large amount of industrial control equipment deployment investment costs. More importantly, the centralized control system can achieve unified control and optimization of global resources. This paper introduces the virtualization 5G cloud chemical industry control technology with two parts: technical content and technical route. Third, this paper proposes a cloud-based allocation of control resources and a cloud–network integration collaboration scenario and designs the 5G cloud-based programmable logic controller (PLC) and EtherCAT fusion system and the EtherCAT and TSN fusion system for real-time motion control. Through the testing of the end-to-end delay and cross-network time synchronization accuracy of the actual system, the current end-to-end delay of network transmission is less than 5 ms, the cross-network time synchronization error is between 100–400 us, and the accuracy is less than 100 ns These performance indicators reach the current industry-leading level. The test platform verifies the scientificalness and rationality of the new industrial network architecture. Finally, the integration problems and potential solutions of efficiency, reliability, and security are discussed in the future industrial automation system integrating network, control, and computing.

Objective There has been no definite consensus on the ideal depth of acetabuloplasty, especially in cases of global pincer femoroacetabular impingement (FAI). This study aims to determine whether the depth of acetabuloplasty influences postoperative outcomes in cases of global pincer FAI. Methods Data were retrospectively collected from patients with global pincer FAI who underwent hip arthroscopy with a minimum follow‐up period of 2 years from May 2014 to December 2018. Patients with global pincer FAI were subdivided into low or high resection depth groups based on whether the intraoperative acetabular rim was resected by more than 3 mm. Radiographic measurements; arthroscopic procedures; preoperative and postoperative PROs were recorded. Achievement of MCID and PASS was compared for the VAS, mHHS, HOS‐ADL, and iHOT‐12. A paired Student t‐test was used to evaluate the significance of preoperative and postoperative PROs and two‐tailed unpaired Student t‐test was used to compare demographic data and PROs between different groups. MCID and PASS were evaluated using the chi‐square test or the Fisher's exact test. Results A total of 41 hips with global pincer FAI (15 and 26 patients in low or high resection depth groups, respectively) were included in this study. Both groups showed significant postoperative improvements in the scores of all PROs (p < 0.001). Compared to the low resection depth group, the high resection depth group had a lower degree of improvement through hip arthroscopy, which manifested as lower postoperative mHHS scores (94.29 vs. 85.08, p = 0.006), higher VAS scores (0.93 vs. 2.54, p = 0.002), and lower improvements in VAS (−5.00 vs. −3.35, p = 0.028), HOS‐ADL (34.99 vs. 23.90, p = 0.017) and iHOT‐12 (39.89 vs. 29.27, p = 0.036). Patients in high resection depth group were less likely to achieve the MCID for the VAS score compared to low resection depth group in significant (73.3 vs. 26.9%, p = 0.004). Conclusions For patients with global pincer, the outcomes in high resection depth group were slightly worse than the the low resection depth group. It is indicated that excessive resection of the acetabular rim during the procedure should be avoided.

Abstract Background Hip joint capsular ligaments serve a fundamental role in balancing functional mobility and joint stability. However, few studies had focused on postoperative capsule changes in patients with borderline developmental dysplasia of the hip (BDDH). Purpose To evaluate the integrity and thickness of anterior hip capsular thickness on pre and postoperative MRI in BDDH patients. Study design Case series study; Level of evidence III. Methods A retrospective analysis was performed using data from BDDH patients who had arthroscopy between 2016 and 2019. Two groups were created and propensity-score matched based on whether the capsule was sutured. The study group comprised patients who have undergone routine capsule repair between 2018 and 2019. The control group includes BDDH patients with unrepaired capsulotomy between 2016 and 2018. Capsular integrity and thickness were measured on MRI before surgery and at least one year postoperatively. Furthermore, analysis was performed on correlations between the presence of a capsular defect and related factors. Results Propensity-score matching yielded 37 hips in the repair group and 37 hips in the non-repair group. There were no significant differences detected in age, sex, and BMI between the two groups. MRI detected capsular defects in 3 hips (8.1%) in the repair group and 10 hips (27.0%) in the non-repair group (p = 0.032). The defect was found to be along the interportal capsulotomy line in all capsular defect cases. Moreover, the postoperative anterior capsule thickness in the study group was significantly thinner compared with preoperative (2.9 ± 0.5 mm vs 3.7 ± 0.6 mm; p

Objective Global pincer is a relatively rare form of pincer deformity and is typically associated with technical challenges during surgery. So far, controversy remains whether patients with global pincer have equivalent surgical outcomes compared to patients with focal pincer. This study compares the clinical outcomes of arthroscopic treatment between patients with global pincer femoroacetabular impingement (FAI) and focal pincer FAI in the Chinese population. Methods Data were retrospectively collected from patients with global and focal pincer FAI who underwent hip arthroscopy with a minimum two‐year follow‐up between April 2016 and December 2018. Radiographic measurements, arthroscopic procedures, preoperative and postoperative patient‐reported outcomes (PROs) including modified Harris hip score (mHHS), hip outcome score‐activities of daily living (HOS‐ADL), international hip outcome tool–12 (iHOT‐12), and visual analogue scale (VAS) scores, rates of revision surgery and conversion to total hip arthroplasty (THA) were recorded. Achievement of minimal clinically important difference (MCID) and patient acceptable symptomatic state (PASS) was compared for the VAS, mHHS, HOS‐ADL, and iHOT‐12 scores between groups. Results The total of 33 and 167 patients were included in the global and focal group, respectively. There were no intergroup differences in age, gender, body mass index or follow‐up times. Lateral center‐edge angle (LCEA) was reduced in both groups postoperatively. Both groups demonstrated significant improvements in PROs compared with preoperative levels at the final follow‐up. The preoperative scores showed significant differences in terms of mHHS (60.34 vs 62.90, P = 0.031) and HOS‐ADL (61.45 vs 64.74, P = 0.022) scores between two groups, and the improvement of HOS‐ADL score was significantly higher in global group (P = 0.027). However, the postoperative scores, including VAS, mHHS, HOS‐ADL, and iHOT‐12 scores, showed no significant differences between two groups. And there were no significant differences in the rate of meeting the PASS and MCID between groups. One (3.0%) in the global group and six (3.6%) patients in the focal group underwent revision arthroscopy respectively, with no significant difference (P = 0.876). There were no conversions to THA in both groups. Conclusions Arthroscopic management of global pincer FAI can achieve excellent functional scores at minimum 2‐year follow‐up. The outcomes were similar to focal pincer FAI patients with a low rate of secondary procedure.

Abstract Background Subspine impingement (SSI) does not have effective diagnostic criteria, especially in patients who also have femoroacetabular impingement (FAI). The classification of anterior inferior iliac spine (AIIS) morphology via three-dimensional CT is controversial. Purpose To propose a method for ultrasound-guided AIIS injection as a way to diagnose SSI and evaluate the accuracy of radiography methods, including 3-D CT and MRI, as well as intraoperative findings. Methods Patients diagnosed with FAI between September 2020 and December 2021 were evaluated in this prospective study. Those who met the criteria were included in the ultrasound-guided AIIS injection test. Whether the pain was relieved after injection was recorded in the radiology report. Patients who experienced significant relief of the anterior groin pain (more than 50%) after the AIIS injection were considered positive responders. Among these patients, radiography materials, including AIIS morphology as measured by 3-D CT as well as superior capsular oedema on MRI, were compared. The presence of congestion or bruising on the capsule side of the labrum corresponding to the AIIS during hip arthroscopy was recorded. Results A total of 73 patients with FAI underwent the ultrasound-guided AIIS injection test. Prevalence rates of 13.70% (10/73), 58.90% (43/73), 23.29% (17/73) and 4.11% (3/73) were recorded for Type I, Type IIA, Type IIB and Type III AIISs, respectively. Thirty-six patients had positive responses to injection, and 37 patients had negative responses to injection. None of the patients with Type I, 23 (53.49%) patients with Type IIA, 11 (64.71%) patients with Type IIB and 2 (66.7%) patients with Type III AIISs had positive responses to the injection. A total of 57.14% of patients with Type II or Type III AIIS had positive responses to the injection. The proportions of patients with superior capsular oedema on MRI in the Type I, Type IIA, Type IIB, and Type III AIIS groups was 0, 30.23, 29.41 and 0%, respectively. Among non-Type I AIIS patients, those who reported positive responses to the injection had a higher incidence of superior capsular oedema (38.89% vs. 14.81%, P = 0.036), but they had no significant differences in the proportion of congestion or bruising of the labrum (47.22% vs. 37.04%, P = 0.419). The results showed that no pairs of methods—ultrasound-guided injection, MRI, and intraoperative findings—achieved good consistency (κ = 0.222, κ = 0.098 and κ = − 0.116). Conclusions Radiographic methods including 3-D CT and MRI as well as the intraoperative findings of the labrum cannot be considered an accurate and reliable basis for the diagnosis and treatment of SSI in FAI patients. It is suggested that ultrasound-guided AIIS injections be combined with radiography to better diagnose SSI. Level of Evidence IV, case series.

Abstract Background Cholesterol can trigger degenerative processes in the chondrocytes. The internal layer of the hip labral consists of cartilage-specific type II collagen-positive fibrocartilage. The purpose of this study was to compare outcomes after arthroscopy labral repair in FAIS patients with preoperative hyperlipidemia to a control group with no hyperlipidemia. Methods Data were prospectively collected and retrospectively reviewed for FAIS patients who had arthroscopy 2019. Patients with hyperlipidemia were 1:1 propensity-score matched to patients without hyperlipidemia. Patient-reported outcomes (HOS-ADL, iHOT-12, mHHS), VAS scores, radiographic measures, performed procedures, complications, and revision surgery were compared and analyzed for both groups. Results A total of 41 patients with hyperlipidemia and 41 patients without hyperlipidemia were found using propensity-score matching. When compared to preoperative levels, both groups demonstrated significant improvements in PROs and VAS scores at the final follow-up. Besides, there were no significant differences in preoperative scores and final outcome scores between the groups. Besides, there were no other differences in revision rate and the rate of meeting the PASS and MCID between the study and the control groups. Conclusion It was demonstrated in this study that FAIS patients with hyperlipidemia can expect to experience similar good short-term patient-reported outcomes as compared with patients without hyperlipidemia. Level of evidence Case-series study; Level of Evidence: Level III.

Applying fifth-generation mobile communication networks (5G) and time-sensitive networking (TSN) has become a new trend in industrial automation. As the new generation of mobile communication technology, 5G is featured with a large bandwidth, low latency, ultrareliable connection, and multiservice slicing capacities. As the evolution goal of industrial ethernet, TSN is featured with a deterministic transmission with bounded latency and jitter and guaranteed high reliability. Both technologies have been designed to provide converged communication for various services on common network infrastructure. 5G and TSN coordination can effectively promote the integration of Information Technology (IT) and operational technologies (OT), which will be a key enabler of the industrial internet. Therefore, the collaborative transmission of 5G and TSN has become a focus for the industry and academe. “5G + TSN” is envisioned to be the basic communication network for future smart factories, which can integrate various field-level industrial communication technologies and ensure end-to-end industrial data transmission reliability. However, 5G and TSN networks are different in the transmission methods, protocols, control and management mechanisms, etc. How to realize an efficient interconnection and coordination of 5G and TSN is a hot topic and difficult task currently. Following the general requirements of digital, digital-networked, and new-generation intelligent manufacturing, this article first introduced the state-of-the-art of time-sensitive networks, and it also elaborated on the standardization progress of 5G supporting TSN in 3GPP. This work then emphasized the main challenges for the coordinated transmission of 5G and TSN networks and analyzed key technologies such as time synchronization, connection enhancement, and unified resource management to support the coordination of 5G and TSN heterogeneous networks. Finally, the application scenarios of “5G + TSN” in a smart factory were given, aiming to deepen the integration of 5G into industrial control and flourish 5G-based industrial applications.

Abstract Background Though radiotherapy has been widely used for knee pigmented villonodular synovitis (PVNS), there is few literatures about radiotherapy for the treatment of PVNS hip. Thus, the purpose of this study was to analyze the clinical outcomes of endoscopic synovectomy with/without radiotherapy postoperatively of PVNS hip. Methods We performed a retrospective study of patients who underwent endoscopy in our hospital from November 2010 to January 2021. Inclusion criteria was patients with magnetic resonance image (MRI) signs, endoscopic findings and/or histological evidence of PVNS. Exclusion criteria was patients lost follow-up. All patients underwent synovectomy endoscopically and were divided into two groups depending on receiving postoperative radiotherapy or not. The primary outcome measurements were the recurrence of PVNS, receiving revision, and/or converting to total hip arthroplasty (THA). The secondary outcome measurements were the patient-reported outcome (PRO) collected at pre- and post-operation, which consist of Hip Outcome Score Activities of Daily Living (HOS-ADL), modified Harris Hip Score (mHHS), International Hip Outcome Tool-12 (IHOT-12), Non-arthritic Hip Scale (NAHS), and visual analog scale (VAS). Results In a case series of 16 patients (8 cases of male, 50%), 4 (25%) cases were localized type and 12 (75%) cases were diffuse type. The average follow-up was 44.8 ± 38.2 months (range,3 to 110). 8 (50%) cases (6 diffuse cases and 2 localized cases) received radiotherapy postoperatively, and the rest (6 diffuse cases and 2 localized cases) received endoscopic treatment alone. At the latest follow-up, 3 (18.75%) cases (2 diffuse cases and 1 localized case) who did not receive radiotherapy converted to arthroplasty. The preoperative HOS-ADL, mHHS, IHOT-12, NAHS, VAS scores of remaining 13 patients were 63.1 ± 19.1 (range,32.0 to 98.8), 54.8 ± 20.1 (range, 10.0 to 77.0), 50.9 ± 15.4 (range, 31.0 to 76.6),51.6 ± 15.9 (range, 20.0 to 84.4), 6.0 ± 1.4 (range,4.0 to 8.0) points, respectively. The latest HOS-ADL, mHHS, IHOT-12, NAHS, VAS scores of the 13 patients were 79.7 ± 10.8 (range, 58.0 to 97.6), 78.6 ± 9.1 (range,55.0 to 87.0), 74.7 ± 9.7 (range, 55.6 to 91.0), 78.9 ± 18.7 (range,20.0 to 92.5), 3.1 ± 1.2 (range,2.0 to 6.0) points respectively. Conclusion Endoscopic synovectomy can achieve satisfactory PRO in PVNS hip patients. Besides, postoperative adjuvant radiotherapy can achieve higher hip survivability than synovectomy alone in this present study.

Abstract Background The acetabular fossa often showing the first signs of degeneration, Central acetabular osteophytes (CAO) have been increasingly recognized during hip arthroscopy. The purpose of this study was to investigate the condition of CAO in BDDH hips and compare cotyloid fossa size between the BDDH and the non-BDDH hips on CT images. Methods We performed a retrospective analysis of prospectively collected data of hip CT images of FAI or labral injury patients. A 1:2 propensity-score matched observational study comparing the linear length of cotyloid fossa was analyzed. Cotyloid fossa width (CFW) and cotyloid notch width (CNW) were measured on axial images, cotyloid fossa height (CFH) and cotyloid fossa depth (CFD) were measured on coronal images. Within the CAO patients, we performed central acetabular decompression (CAD) and then observed the morphology change in fossa. Results Propensity-score matching yielded 61 BDDH hips and 122 non-BDDH hips. BDDH hips had a higher prevalence of CAO and a decreased linear length of cotyloid fossa (CFW, CFH and CNW). In the BDDH group, 33 hips underwent CAD, postoperative CFW, CFH and CNW were significantly increased (p

The hip joint is the largest weight‐bearing joint in the body and is surrounded by dense capsules and thick muscles. Hip arthroscopic techniques are suitable for the treatment of hip‐related conditions. These minimally invasive techniques have rapidly developed in China since 2007. Moreover, they have been used in the treatment of gluteal muscle contracture, snapping hip syndrome, femoral acetabular impingement, acetabular labral injury, hip labral calcification, synovial chondroma, osteoid osteoma, synovitis, osteonecrosis of the femoral head, and developmental dysplasia of the hip. This technique has showed its advantage in the total debridement of lesions, precision treatment, and less trauma. However, we lack understanding of the overall development of arthroscopic techniques in China. This review illustrates the recent development of hip arthroscopic techniques in China and related research progress.

In recent years, with the development of imaging and arthroscopy techniques, and a deep understanding of the pathogenic mechanism of femoroacetabular impingement syndrome (FAI), more and more scholars have gained a greater knowledge of the diagnosis and treatment of the disease. FAI not only has abnormal bone structure, such as cam deformity at the femoral head-neck junction, acetabular osteophyte formation, and bone cyst at the femoral or acetabulum, but also leads to the soft tissue injury of the hip joint, like acetabulum cartilage and labrum lesion, which might accelerate the progression of hip osteoarthritis. The incidence of bone cyst or synovial hernia at the femoral head-neck junction is not rare, which was seen as a sign of impingement. However, there is a paucity of literature about the treatment of bone cyst and the clear standard protocols of treatment, especially large or polycystic cysts. In this study, we reported a case of Cam FAI complicated with a giant bone cyst at the femoral head-neck junction and its characteristics and arthroscopic treatment. We also reviewed relevant documents and summarized the protocols of management of FAI complicated with femoral head-neck bone cyst for clinical reference.

Abstract. Background:. Heterotopic ossification (HO) is a known complication of hip arthroscopy. We investigated incidence of HO after hip arthroscopy and determined whether revision for HO improved outcome. Methods:. A retrospective study was conducted on 242 patients (140 men and 102 women, mean age: 36.2 ± 9.5 years) who underwent hip arthroscopy for femoroacetabular impingement (FAI) between January 2016 and January 2018. The average follow-up period was 22.88 ± 11.74 months (range: 11–34 months). Thirteen (5.37%) cases of HO (six men and seven women, five left hips and eight right hips; mean age: 37.5 ± 4.7 years) were observed. Among them, four cases with HO with obvious pain symptoms and persistent non-remission underwent revision surgery to remove HO. Monthly follow-up was conducted. Visual analog scale (VAS), modified Harris Hip Score (mHHS), and non-Arthritis Hip Score (NAHS) were evaluated and compared between HO and non-HO patients. Independent sample t test, Mann-Whitney U test and the Chi-square test were used for inter-group comparisons. HO degree was evaluated using Brooker classification. Symptoms and function were evaluated before and after revision. Results:. A total of 242 patients were involved in this study. Thirteen cases (5.4%) had imaging evidence of HO. Nine (9/13) were classified as Brooker stage I, three (3/13) Brooker stage II, and one (1/13) Brooker stage III. HO was detected by ultrasonography as early as 3 weeks after operation. After primary surgery, the mHHS of the HO group and non-HO group increased by 13.00 (8.50, 25.50) and 24.00 (14.00, 34.50) points (Z = −1.80, P = 0.08), NAHS increased by 18.00 (9.50, 31.50) and 26.00 (13.50, 36.00) points (Z = −1.34, P = 0.18), and VAS decreased by 3.00 (2.00, 4.00) and 4.00 (3.00, 4.50) points (Z = −1.55, P = 0.12). Average follow-up time after revision was 9.00 ± 2.94 months; mHHS increased by 34.75 points (t = −55.23, P