Characteristics of hip involvement in patients with ankylosing spondylitis in Korea

Literature review of non-pharmacological treatment for patients with axial spondyloarthritis

Axial spondyloarthritis (axSpA) is a chronic inflammatory disorder affecting the sacroiliac joints and axial spine. Along with pharmacotherapy, non-pharmacological interventions for axSpA are crucial and constitute the cornerstone of treatment. Here, we review the evidence for non-pharmacological treatment of axSpA as a basis for the 2023 Korean treatment recommendations for patients with axSpA. The effectiveness of the core non-pharmacological approaches, such as education, smoking cessation, and exercise, has been reaffirmed. High-quality research on surgical treatment is limited. However, total hip replacement is advised in patients with ongoing pain or disability and visible structural damage to the hip on imaging. Urgent spinal intervention should be considered in cases of acute spinal pain with neurological deficiency or concurrent unstable fractures. Evidence for complementary therapies, including spas and acupuncture, remains insufficient.

Causality between Ankylosing Spondylitis and osteoarthritis in European ancestry: a bidirectional Mendelian randomization study

Objective

To explore the bidirectional causal relationship between Ankylosing Spondylitis (AS) and Osteoarthritis (OA) at the genetic level within the European ancestry.

Methods

We implemented a series of quality control steps to select instrumental variables (IVs) related to the exposure. We conducted two-sample Mendelian randomization (MR) using the inverse-variance weighted method as the primary approach. We adjusted significance levels using Bonferroni correction, assessed heterogeneity using Cochrane's Q test. Sensitivity analysis was conducted through leave-one-out method. Additionally, external datasets and relaxed IV selection criteria were employed, and multivariate MR analyses were performed for validation purposes. Finally, Bayesian colocalization (COLOC) analysis identified common genes, validating the MR results.

Results

The investigation focused on the correlation between OA and AS in knee, hip, and hand joints. MR results revealed that individuals with AS exhibit a decreased risk of knee OA (OR = 0.9882, 95% CI: 0.9804-0.9962) but no significant increase in the risk of hip OA (OR = 0.9901, 95% CI: 0.9786-1.0018). Conversely, AS emerged as a risk factor for hand OA (OR = 1.0026, 95% CI: 1.0015-1.0036). In reverse-direction MR analysis, OA did not significantly influence the occurrence of AS. Importantly, minimal heterogeneity was observed in our MR analysis results (p > 0.05), and the robustness of these findings was confirmed through sensitivity analysis and multivariate MR analysis. COLOC analysis identified four colocalized variants for AS and hand OA (rs74707996, rs75240935, rs181468789, and rs748670681).

Conclusion

In European population, individuals with AS have a relatively lower risk of knee OA, whereas AS serves as a risk factor for hand OA. However, no significant causal relationship was found between AS and hip OA. Additionally, it offers novel insights into genetic research on AS and OA.

Korean treatment recommendations for patients with axial spondyloarthritis

We aimed to develop evidence-based recommendations for treating axial spondylarthritis (axSpA) in Korea. The development committee was constructed, key clinical questions were determined, and the evidence was searched through online databases including MEDLINE, Embase, Cochrane, KoreaMed, and Kmbase. Systematic literature reviews were conducted, quality of evidence was determined, and draft recommendations were formulated according to the Grading of Recommendations Assessment, Development, and Evaluations methodology. Recommendations that reached 80% consensus among a voting panel were finalized. Three principles and 21 recommendations were determined. Recommendations 1 and 2 pertain to treatment strategies, regular disease status assessment, and rheumatologist-steered multidisciplinary management. Recommendations 3 and 4 strongly recommend patient education, exercise, and smoking cessation. Recommendations 5-12 address pharmacological treatment of active disease using nonsteroidal anti-inflammatory drugs, glucocorticoids, sulfasalazine, biologics, and Janus kinase inhibitors. Recommendations 13-16 address treatment in stable disease. We suggest against spa and acupuncture as therapies (Recommendation 17). Recommendations 18 and 19 pertain to total hip arthroplasty and spinal surgery. Monitoring of comorbidities and drug toxicities are recommended (Recommendations 20 and 21). Recommendations for axSpA treatment in a Korean context were developed based on comprehensive clinical questions and evidence. These are intended to guide best practice in the treatment of axSpA.

Radiosynovectomy of the hip joint - preliminary experience

Introduction

Radiosynovectomy (RSV) is a minimally invasive method of treating and controlling joint inflammation refractory to conventional pharmacotherapy. It consist in intraarticular injection of radioactive colloids which irradiate the inflamed synovial membrane to cause its subsequent involution. Despite the fact that hip joint involvement is quite common in systemic inflammatory arthropathies, hip joint RSVs are rarely performed. The aim of this paper is to assess to safety and efficacy of hip joint radioisotope treatment.

Material and methods

We retrospectively analyzed the effects of 21 hip joint RSVs performed in 14 patients (10 female, 4 male; aged 8 to 79; mean age 48 years). Before the RSV, all the patients underwent clinical and ultrasound examination. The radiosynovectomies were performed using rhenium-186 sulfide under ultrasound guidance. Each patient underwent post-therapeutic scintigraphy to assess intraarticular distribution of the radiopharmaceutical. The effects of the treatment were assessed clinically and ultrasonographically during at least 2 follow-up visits 3 and 6 months after the RSV.

Results

In 9 cases, we observed complete resolution of symptoms 3 and 6 months after the RSV. Four patients had only a partial response and required repeated treatment, and all responded well to the second RSV. In 4 patients the treatment had no significant effect, and no repeated treatment attempt was made. All the responders suffered from inflammatory arthropathies; the non-responders had osteoarthritis, with no history of systemic diseases. In all the patients, no significant adverse effects were observed; in particular there were no radiation burns or infections. All post-therapeutic scintigrams showed proper, intraarticular distribution of the radiopharmaceutical.

Conclusions

Radiosynovectomy of the hip joint in systemic joint diseases, especially performed using ultrasound-guidance, is a safe and effective treatment modality.

Korean treatment recommendations for patients with axial spondyloarthritis

We aimed to develop evidence-based recommendations for treating axial spondylarthritis (axSpA) in Korea. The development committee was constructed, key clinical questions were determined, and the evidence was searched through online databases including MEDLINE, Embase, Cochrane, KoreaMed, and KMbase. Systematic literature reviews were conducted, quality of evidence was determined, and draft recommendations were formulated according to the Grading of Recommendations Assessment, Development, and Evaluations methodology. Recommendations that reached 80% consensus among a voting panel were finalized. Three principles and 21 recommendations were determined. Recommendations 1 and 2 pertain to treatment strategies, regular disease status assessment, and rheumatologist-steered multidisciplinary management. Recommendations 3 and 4 strongly recommend patient education, exercise, and smoking cessation. Recommendations 5~12 address pharmacological treatment of active disease using nonsteroidal anti-inflammatory drugs, glucocorticoids, sulfasalazine, biologics, and Janus kinase inhibitors. Recommendations 13~16 address treatment in stable disease. We suggest against spa and acupuncture as therapies (Recommendation 17). Recommendations 18 and 19 pertain to total hip arthroplasty and spinal surgery. Monitoring of comorbidities and drug toxicities are recommended (Recommendations 20 and 21). Recommendations for axSpA treatment in a Korean context were developed based on comprehensive clinical questions and evidence. These are intended to guide best practice in the treatment of axSpA.

Intraoperative picture of hip joint lesion in ankylosing spondylitis: data from a retrospective analysis

In population of Russian patients with ankylosing spondylitis (AS), the frequency of clinical manifestations (pain and limitation of functions) of coxitis reaches 56%. Total hip arthroplasty (THA) can be considered as the only alternative that can relieve the suffering of the patient. Radiography and magnetic resonance imaging are widely used methods for assessing structural damage to the hip joint in AS. However, at the moment these methods can’t allow us to fully describe the lifetime changes of these joints. The aim of the study: to analyze the external changes of the femoral heads (HF) and acetabulums during the THA in patients with AS. Materials and methods. The retrospective study included 170 patients with a reliable diagnosis of AS, who met the modified New York criteria of 1984, who were treated in the traumatological and orthopedic department of the V.A. Nasonova Research Institute of Rheumatology in the period from 1998 to 2020, all patients underwent THA as planned. Most of them were male (80.6%). The average age of patients was 38.1±11.3 years and the average duration of the disease since the onset of the first symptoms was 17.0±8.5 years. The duration of pain in hip joints before performing THA is 7.4±4.8 years. The assessment of macroscopic changes in the FH and acetabulum was performed intraoperatively. Results and discussion. Acetabulum protrusion was detected in 108 (63.5%) patients, bone cysts – in 65 (38.2%). Filling of acetabulum with granulation tissue was recorded in 155 (91.2%) patients, presence of osteophytes on its edges – in 153 (90%). Cartilage in the acetabulum was completely absent in 122 (71.8%) patients. FH deformation was detected in 98.2% of cases, erosion in 46.4%. Cartilage on FH was completely absent in 130 (76.5%) patients. In 119 (70%) patients, macroscopic signs of osteonecrosis of FH were found. 79 (46.4%) patients had ankylosis of the hip joint, including fibrous ankylosis – in 77.2% of patients and bone ankylosis – in 22.8%. Conclusion. In patients with AS, the necessity for THA occurs on average after 7.4±4.8 years from the moment of the appearance of first clinical signs of coxitis. In 70% of cases, the macroscopic picture of hip joint lesion was characterized by the development of Avascular necrosis of the femur head (AVNFH), in most patients there was no cartilage in the most loaded segments of acetabulum and FH, in almost half of cases – ankylosis of hip joint and mainly fibrous (77.2%).

Associated Factors with the Severity of Hip Involvement in Spondyloarthritis and Efficacy of TNF α Inhibitors in these Patients

INTRODUCTION

Hip involvement in patients with spondyloarthritis is responsible for disability and functional impairment. Its treatment is not codified. Our study aimed to determine the associated factors with moderate and severe hip involvement in spondyloarthritis patients. It also aimed to assess the efficacy of tumour necrosis factor inhibitors (TNFi) on hip disease.

METHODS

We conducted a cross-sectional study, including 44 spondyloarthritis patients with hip involvement. Hip involvement was diagnosed based on radiographic findings. We assessed the following parameters: Bath Ankylosing Spondylitis Metrology Index (BASMI), Bath Ankylosing Spondylitis Radiology Index (BASRI), patient global assessment (PGA), and Lequesne index. We compared these parameters and the mean radiographic joint space width between the time of the study to those right before the use of TNFi.

RESULTS

Hip involvement was bilateral in 31 patients. The mean age was 44.56±12.21 years. There were 29 men. Severe and moderate involvement (BASRI-hip>3) was reported in 21 hips from 75 affected. These patients were older and had longer diagnosis delays than patients with BASRI- hip<3. They had a higher body mass index and more limited spine mobility (BASMI). Functional hip impairment assessed by the Lequesne index was higher in these patients. TNFi prescribed in 23 patients with hip involvement, led to an improvement in the Lequesne index (12.75 vs 7.5, p: 0.001) and PGA (7 vs 2, p: 0.001). However, the mean joint space width remained unchanged (3.8 vs 3.7mm, p: 0.532).

CONCLUSION

Our study showed that higher body mass and Lequesne indexes are associated with moderate and severe hip involvement. TNFi may improve both the Lequesne index and PGA and stabilize the radiological findings.

Risk Factors for Spinal Structural Damage in a Chinese Cohort With Ankylosing Spondylitis

OBJECTIVES

A cross-sectional study was conducted in 270 Chinese patients with ankylosing spondylitis (AS) in order to identify potential risk factors for severity of spinal structural damage.

METHODS

Two hundred seventy AS patients fulfilled the Modified New York Criteria. Computed tomography (CT) was used to scan sacroiliac and hip joints, and radiography was used to scan anteroposterior and lateral lumbar spine, as well as lateral cervical spine. Bath Ankylosing Spondylitis Radiology Index and modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) were scored in duplicate.

RESULTS

One hundred eighty-three patients had low mSASSS (mSASSS, <10), and 87 patients had high mSASSS (mSASSS, ≥10). Univariate analysis revealed that AS age of onset, body mass index (BMI), smoking duration, duration of symptoms, diagnostic delay, hip involvement, and sacroiliitis grade were significantly associated with the risk of having high mSASSS after adjustment (all p's < 0.05). Hip involvement interacted significantly with BMI and smoking duration in a graded manner. Particularly, relative to patients with low BMI-negative hip involvement, those with high BMI-negative hip involvement, low BMI-positive hip involvement, and high BMI-positive hip involvement had a 1.94-fold, 3.29-fold, and 5.07-fold increased risk of high mSASSS (95% confidence interval, 0.84-4.47, 1.37-7.89, and 1.97-13.06, p = 0.118, 0.008, and 0.001, respectively). Finally, a nomogram graph based on 7 significant risk factors was generated with substantial prediction accuracy (concordance index, 0.906).

CONCLUSIONS

We have identified 7 potential risk factors for the severity of spinal structural damage in Chinese AS patients. Importantly, positive hip involvement, combined with high BMI or long smoking duration, was associated with a remarkably increased risk of having severe spinal structural damage.

Total hip arthroplasty in fused hips with spine stiffness in ankylosing spondylitis

Ankylosing spondylitis (AS) is characterized by involvement of the spine and hip joints with progressive stiffness and loss of function. Functional impairment is significant, with spine and hip involvement, and is predominantly seen in the younger age group. Total hip arthroplasty (THA) for fused hips with stiff spines in AS results in considerable improvement of mobility and function. Spine stiffness associated with AS needs evaluation before THA. Preoperative assessment with lateral spine radiographs shows loss of lumbar lordosis. Spinopelvic mobility is reduced with change in sacral slope from sitting to standing less than 10 degrees conforming to the stiff pattern. Care should be taken to reduce acetabular component anteversion at THA in these fused hips, as the posterior pelvic tilt would increase the risk of posterior impingement and anterior dislocation. Fused hips require femoral neck osteotomy, true acetabular floor identification and restoration of the hip center with horizontal and vertical offset to achieve a good functional outcome. Cementless and cemented fixation have shown comparable long-term results with the choice dependent on bone stock at THA. Risks at THA in AS include intraoperative fractures, dislocation, heterotopic ossification, among others. There is significant improvement of functional scores and quality of life following THA in these deserving young individuals with fused hips and spine stiffness.

Risk factors for radiological hip involvement in patients with ankylosing spondylitis

OBJECTIVE

Our study aimed to explore the potential risk factors for radiological hip joint involvement in patients with ankylosing spondylitis (AS).

METHODS

This cross-sectional convey collected the clinical data, laboratory indicators, and radiographic data of patients with AS. Radiographic hip joint involvement was defined as a Bath Ankylosing Spondylitis Radiology Hip Index (BASRI-hip) score ≥2. Multivariate logistic regression analyses were conducted to explore the potential risk factors for radiological hip involvement in patients with AS.

RESULTS

Based on BASRI-hip score, all enrolled 386 patients with AS were classified as patients involving with radiological hip joint involvement (BASRI-hip ≥2; n=203) and those without it (BASRI-hip ≤1; n=183). Mean age of enrolled patients with AS were 36.7±11.9 years, and 320 (82.9%) patients were male. Mean course of disease was 10.7±8.3 years, and 349 (90.4%) patients were with a positive HLAB27. Multivariate analyses indicated that Juvenile onset (onset age ≤16 years) (odds ratio [OR]=4.159, 95% confidence interval [CI], 1.779-9.721, p<0.001), body mass index (BMI) <18.5 kg/m2 (OR=1.986, 95%CI 1.187-3.323, p=0.009), continuous nonsteroidal anti-inflammatory drug (NSAID) use (OR=0.351, 95%CI 0.155-0.794, p=0.012), and bone mass below the expected range for age (Z score ≤-2) (OR=2.791, 95%CI 1.456-5.352, p=0.002) were independently associated with radiological hip joint involvement in patients with AS.

CONCLUSIONS

The potential risk factors for radiological hip joint involvement were juvenile onset, lower BMI, and bone mass below the expected range for age. Furthermore, continuous NSAID use was the protective factor for radiological hip joint involvement in these population.

Analysis of Bone Strength and Bone Turnover Markers in Ankylosing Spondylitis with Radiological Hip Involvement

Background

Limited clinical data are available on bone loss in ankylosing spondylitis (AS) patients with hip involvement, especially for bone strength. The purpose of this study was to analyze bone strength and bone turnover markers in AS patients with hip involvement.

Material/Methods

The stiffness index (SI) calculated by quantitative ultrasound (QUS) was used to compare the bone strength between patients with AS with radiographic hip involvement (RHI-AS, BASRI-hip ≥2) and those without radiographic hip involvement (WORHI-AS, BASRI-hip ≤1). The Spearman correlation test was used to evaluate the association between SI and bone turnover markers [TP1NP, OC, β-CTx, 25(OH)VD3, and PTH].

Results

RHI-AS (BASRI-hip ≥2) patients accounted for 52.2% (177/339) of all patients. There was no significant difference in most of the basic clinical features between RHI-AS and WORHI-AS patients, except for age and BMI. After adjusting for confounding factors (age and BMI), the stiffness index (SI) of RHI-AS patients was significantly lower than that of WORHI-AS patients (OR_adj=0.982, 95% CI_adj=0.968~0.997, P_adj=0.017). The Z scores calculated by SI were lower in RHI-AS patients (OR_adj=0.802, 95% CI_adj=0.679~0.949, P_adj=0.01). Among the 5 bone turnover markers in the RHI-AS patients, only 25(OH)VD3 had a correlation with SI (rho=0.279, P=0.001).

Conclusions

AS patients have lower bone strength once the disease progresses to include radiologic hip involvement. Treatment of vitamin D deficiency may be an effective way to improve bone strength in AS patients with hip involvement.

Root Joint Involvement in Spondyloarthritis: A Post-hoc Analysis from the International ASAS-PerSpA Study

OBJECTIVES

Primary objective was to compare the clinical characteristics of spondyloarthritis (SpA) patients with and without root joint disease (RJD+ and RJD-). Secondary objectives were to compare the prevalence of RJD across various SpA subtypes and in different world regions, to compare the SpA axial severity and SpA burden between RJD+ and RJD-.

METHODS

This is a post-hoc analysis of the ASAS-PerSpA study (PERipheral involvement in SpondyloArthritis), which included 4,465 patients with SpA (axial (axSpA), peripheral (pSpA), psoriatic (PsA), inflammatory bowel disease, reactive and juvenile) according to the rheumatologist's diagnosis. RJD was defined as the "ever" presence of hip or shoulder involvement related to SpA, according to the rheumatologist. The patient's characteristics were compared between RJD+ and RJD-. Multivariable stepwise binary logistic regression analyses were conducted to identify factors associated with "RJD", "hip" and "shoulder" involvement.

RESULTS

RJD was significantly associated with the SpA main diagnosis (highest in pSpA), a higher prevalence of HLA-B27 positivity, enthesitis, tender and swollen joints, CRP, cs-DMARDs, loss of lumbar lordosis and occiput-wall distance > 0. RJD was more prevalent in Asia, and occurred in 1,503 patients (33.7%), with more hip (24.2%) than shoulder (13.2%) involvement. Hip involvement had a distinct phenotype, similar to axSpA (including younger age at onset, HLA-B27 positivity), whereas shoulder involvement was associated with features of pSpA (including older age at onset).

CONCLUSION

RJD+ SpA patients had a distinctive clinical phenotype compared with RJD-. Hip involvement, based on the rheumatologist's diagnosis, was more prevalent than shoulder involvement and was clinically distinct.

A Comprehensive Assessment of Hip Damage in Ankylosing Spondylitis, Especially Early Features

Ankylosing spondylitis (AS) is most common in adolescents and the ultimate result is disability, which places a huge burden on patients and society. Therefore, the key to improve the prognosis of AS is the early diagnosis of hip injury. To examine if AS patients whose hip pain is either absent or minimal might already have observable MRI and X-ray hip changes. Clinical and imaging hip data were systematically analyzed in 200 healthy controls (HC) and 300 AS with varying degrees of hip pain. Forty-four patients with early hip osteoarthritis (OA) served as positive imaging controls. In MRI images, BME lesions in the STIR sequence were much more frequent in AS (62%) compared to HC (2%) (p < 0.0001). Most importantly, 42% of AS with no or minimal hip pain had one or more MRI lesions. This was much more frequent compared to the 2% in HC (p < 0.05). These lesions in AS were observed singly or in combination in the trochanters (8%), femoral heads (12%), and acetabula (13%). Parallel finding that X-ray changes were present in patients with minimal or no hip pain was also observed with X-ray. Based on the normal hip width of HC, joint space narrowing was observed in 94.3% of the entire AS cohort, and importantly 56.7% of AS patients with no or mild hip pain. In these latter patients, functional activities of the hips such as walking were normal. At least 40% of AS patients with minimal or no hip pain might already show MRI and X-ray changes.

Efficacy of needle-knife combined with etanercept treatment regarding disease activity and hip joint function in ankylosing spondylitis patients with hip joint involvement: A randomized controlled study

This study aimed to assess the efficacy of needle-knife (NK) combined with etanercept (NKCE) in attenuating pain, inflammation, disease activity, and improving hip joint function in ankylosing spondylitis (AS) patients with hip joint involvement.Totally, 90 patients with active AS involving unilateral hip joint were enrolled and randomly assigned in 1:1:1 ratio to receive NKCE, NK or conventional drugs (control). The ESR, CRP, hip joint pain Visual Analogue Scale (VAS) score, bath ankylosing spondylitis disease activity index (BASDAI), bath ankylosing spondylitis functional index (BASFI), modified Harris hip score (mHHS), and range of motion (ROM) of affected hip joint were assessed at baseline (W0), after 1-week treatment (W1) and after 24-week treatment (W24).ESR and CRP were decreased in NKCE group compared with NK and control groups, while was not attenuated in NK group compared with control group. Regrading pain and disease activity, NKCE group presented a reduction in hip pain VAS score and BASDAI compared with NK and control groups, and NK group showed a decrease in hip pain VAS score and BASDAI compared with control group. Besides, BASFI was lowered in NKCE and NK groups compared with control group, but similar between NKCE and NK groups. mHHS and hip ROM were raised in NKCE and NK groups compared with control group, but similar between NKCE and NK groups.NKCE decreases hip pain, inflammation, disease activity and improves hip joint function in AS patients with hip joint involvement.

Structural damage and motion rhythm of the spine and hip during trunk lateral bending in ankylosing spondylitis patients with mild to moderate radiographic signs

BACKGROUND

Ankylosing spondylitis causes structural damage and motion restriction in spine. The study was designed to assess structural damage and incoordination pattern between the spine and hip during trunk lateral bending in ankylosing spondylitis.

METHODS

Twenty-three healthy adults and 39 adults with ankylosing spondylitis were recruited from a tertiary care medical centre. Patients with ankylosing spondylitis were divided into two subgroups: sacroiliitis or lumbar-level syndesmophytes (n = 27) and thoracic or cervical-level syndesmophytes (n = 12). An inertia motion system was used to record three-dimensional kinematic data during trunk lateral bending.

FINDINGS

Significant differences were observed in lumbar spine syndesmophyte scores, sacroiliitis severity and Bath Ankylosing Spondylitis Metrology Index between the subgroups. The cervical supraspinous ligaments thickness revealed difference between the ankylosing spondylitis and control group, but the Glasgow Ultrasound Enthesitis Scoring System did not revealed difference. Motion analysis revealed that the ankylosing spondylitis group had a larger hip, cervical rotation and smaller lumbar-hip rhythm than the control group; however, the other motions of the spine and hip were smaller. The sacroiliitis or lumbar-level syndesmophytes group had the largest thoracic rotation among the three groups.

INTERPRETATION

The different lumbar-hip rhythm between ankylosing spondylitis patients depends on syndesmophyte formation levels. Cervical rotation, the Schober test, the chest expansion test, and lumbar-hip rhythm can indicate the levels of bone damage in ankylosing spondylitis. Clinical examination of ankylosing spondylitis should include kinematic measures of both the spine and hips in the early disease stage.

Clinical and MRI response to dose reduction of an etanercept-biosimilar for hip arthritis in patients with ankylosing spondylitis: an observational, retrospective cohort study

OBJECTIVES

Hip arthritis plays a critical role in the prognosis of ankylosing spondylitis (AS). Dose reduction of tumor necrosis factor inhibitors preserves general improvement of AS, so this study attempted to examine the equivalence between Yisaipu® tapering and conventional therapy for hip arthritis in AS patients, using clinical parameters and magnetic resonance image (MRI).

METHODS

AS patients received this etanercept-biosimilar injections (50 mg/week) in the first 12 weeks. Participants in the tapering group were treated with this reagent 50 mg every other week from week 13 to week 24, while the control group kept undergoing full-dose therapy. Clinical and laboratory parameters were assessed at baseline, week 12 and week 24. MRI examination of hip was performed at baseline and week 24.

RESULTS

One hundred and thirty-six patients were enrolled, and 80 of them were in the tapering group. Linear mixed model revealed that main effects of tapering group with control group as reference in disease activity parameters were insignificant (p > 0.05). Main effects of baseline with week 24 as reference were significant (p < 0.05), but main effects of week 12 with week 24 as reference were not (p > 0.05). Prevalence of acute inflammatory change in MRI significantly decreased in the tapering group (76.88% vs 20.00%, p < 0.05) and control group (76.79% vs 19.64%, p < 0.05). Influence of both treatments on acute inflammatory change was equivalent (p > 0.05).

CONCLUSION

Efficacy of Yisaipu® tapering treatment is comparable to the full-dose therapy for hip arthritis in AS patients. Both treatments maintain remission of hip arthritis after patients achieved low disease activity.

The gait deviations of ankylosing spondylitis with hip involvement

OBJECTIVE

The aim of the study was to investigate the gait deviations of ankylosing spondylitis (AS) patients with hip involvement.

METHODS

Thirty-six subjects, including 18 AS patients with hip involvement (AS group) and 18 healthy people (control subjects, CS group), were enrolled in the study. Three-dimensional gait analysis of the AS group and CS group was performed. Kinematic parameters, kinetic parameters and surface electromyography (sEMG) during the gait cycle were measured.

RESULTS

The AS patients with hip involvement had a lower gait velocity, shorter step length and shorter stride length. In the hip angles, there was significantly decreased flexion, excessive abduction and excessive external rotation; there was excessive flexion in the knee and reduction in plantar flexion of the ankle. AS patients had increased forward trunk flexion, excessive obliquity and restricted rotation of the trunk during the gait cycle. The hip moments of the AS group showed a significant reduction in flexion, abduction and external rotation during the gait cycle. The root mean square amplitude of the sEMG for the rectus femoris in the AS group was higher than that in the CS group.

CONCLUSION

The gait deviations in AS patients with hip involvement were described in this study. The gait analysis results demonstrated statistically significant alterations regarding the kinematic and kinetic gait parameters for the patients included in the sample. Coordination and balance were impaired by the disease. An efficient physical exercise plan can be formulated according to the results of gait analysis.

Increased Rates of Both Knee and Hip Arthroplasties in Older Patients with Ankylosing Spondylitis

OBJECTIVE

To determine the risks of primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) in older patients with ankylosing spondylitis (AS).

METHODS

We used administrative data from 1999 to 2013 on US Medicare beneficiaries to identify patients (< 75 yrs old) with AS and a comparison group without AS. Rates of primary THA and primary TKA were computed for each group, and standardized for age, sex, and race. We also examined risks of primary TKA among patients with AS by their THA status.

RESULTS

We analyzed 52,568 patients with AS and 4,617,179 patients without AS. Between 1999 and 2013, the standardized incidence of primary THA in patients with AS doubled from 4.5 per 1000 patient-years (PY) to 9.6 per 1000 PY. Rates of primary TKA were higher in patients with AS than controls in all years. In 2013, the standardized incidence of primary TKA in AS was 12.3 per 1000 PY versus 5.7 per 1000 PY in the comparison group (RR 2.14, 95% CI 1.93-2.38). Rates of primary TKA were twice as high among patients with AS and THA than among those without THA (20.4 vs 10.2 per 1000 PY).

CONCLUSION

Rates of THA in older patients with AS doubled over recent years, outpacing the increase in the general population. Rates of TKA were also substantially higher in older patients with AS. The increased risk of TKA in AS may be a consequence of damage from knee inflammation, or alterations in lower extremity biomechanics due to hip arthritis.

Cross-correlation between spine and hip joint kinematics differs in healthy individuals and subgroups of ankylosing spondylitis patients during trunk lateral flexion

BACKGROUND

The effects of sacroiliitis and syndesmophyte formation on the cross-correlation between spine and hip joint kinematics in ankylosing spondylitis (AS) are poorly understood.

OBJECTIVE

To investigate the cross-correlation between spine and hip joint kinematics differs in healthy individuals and ankylosing spondylitis patients during trunk lateral flexion.

METHODS

Fifty AS patients and thirty-nine healthy adults (controls) were recruited from a medical center. The patients were divided into two subgroups, namely the sacroiliitis (n = 28) and syndesmophyte (n = 22) subgroups. An inertial motion system was used to record kinematic data of spine, pelvic and hip joints during lateral trunk flexion. The maximal cross-correlation coefficient (CCF) and time lag of motion between the spine and hip joint were analyzed.

RESULTS

The syndesmophyte group had the smallest range of motion in all recorded motion. The sacroiliitis group exhibited higher thoracic flexion, pelvic pitch, and pelvic rotation than the other two groups. In the syndesmophyte group, the CCF between lumbar lateral flexion (LLF) and hip abduction were weakly and LLF and hip rotation were strongly correlated. Considering in time sequence, LLF occurred earlier than hip abduction and hip rotation during trunk lateral flexion; however, both AS subgroups exhibited longer time lags than in the control group.

CONCLUSION

The cross-correlation between spine and hip joint kinematics differs in healthy individuals and AS patients during trunk lateral flexion. The motion pattern changes in patients with AS of differing severity may also alter the loads on the spine and hip joints.