Effect of total knee arthroplasty on other joints in patients with rheumatoid arthritis evaluated by 18-FDG-PET

18F-FDG and 18F-NaF PET/CT Global Assessment of Large Joint Inflammation and Bone Turnover in Rheumatoid Arthritis

Rheumatoid arthritis (RA) involves chronic inflammation of synovial joints, causing pain, stiffness, and limited mobility. ¹⁸F-sodium fluoride (NaF) is a PET tracer whose uptake reflects bone turnover, while ¹⁸F-fludeoxyglucose (FDG) shows glucose metabolism and can serve as a marker for inflammation. The aim of this study is to determine the feasibility of calculating the FDG and NaF mean standardized uptake value (SUVmean) in the knee joint, hip joint, and sacroiliac (SI) joint of RA patients and to determine their association with patient characteristics. Prospective FDG-PET/CT as well as NaF-PET/CT imaging was performed on 18 RA patients. The global SUVmean was calculated on FDG-PET/CT and NaF-PET/CT images using a semiautomated CT-based method of segmentation. FDG and NaF uptake were found to be significantly correlated in the knee (r = 0.77, p < 0.001), but not in the hip and SI joints. In the knee, both NaF SUVmean and FDG SUVmean were significantly correlated with body weight, BMI, leptin, and sclerostin levels (p < 0.05). NaF SUVmean was significantly positively correlated with BMI and leptin for both the hip and SI joints (p < 0.05). No significant correlation was observed between either PET parameter and age, height, erythrocyte sedimentation rate (ESR), and interleukins 1 and 6 (IL-1 and IL-6); however, FDG was correlated with inflammatory markers such as C-reactive protein (CRP) and patient global visual analogue scale (VAS-PtGlobal) in some joints. In this study, both FDG and NaF uptake were quantified in large joints of patients with RA using CT segmentation. NaF and FDG SUVmean were correlated with clinical variables related to body weight and adiposity, suggesting that degenerative joint disease may play a larger role in influencing the uptake of these tracers in large joints than RA disease activity. FDG and its correlation with markers of inflammation such as CRP and VAS-PtGlobal suggests that this tracer may serve as a more specific marker for RA disease activity than NaF. Larger prospective and longitudinal data are necessary to gain a better understanding of the roles of FDG and NaF in evaluating RA joint activity in these joints.

Deformity analysis of the lower limb on the coronal plane in patients with rheumatoid arthritis and osteoarthritis

OBJECTIVES

To evaluate joint orientation angles of the coronal plane in patients with rheumatoid arthritis (RA) in comparison with osteoarthritis (OA).

METHODS

In total, 72 patients with RA (90 knees) and 76 patients with OA (90 knees) who underwent total knee arthroplasty were enrolled. The hip-knee-ankle (HKA) angle, mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and joint line convergence angle (JLCA) were measured on preoperative long-leg radiographs in the standing position. Student's t-test was used to assess differences in radiographic data between patients with RA and OA.

RESULTS

In knees with RA and OA, the mean HKA was -3.4 ± 9.4° and -10.6 ± 8.0°, the mean mLDFA was 86.6 ± 3.7° and 88.2 ± 2.7°, the mean mMPTA was 85.9 ± 4.0° and 84.3 ± 3.7°, and the mean JLCA was 2.7 ± 4.2° and 6.8 ± 4.1°. All parameters in the knees with RA were more valgus than those with OA.

CONCLUSIONS

Knees with RA had a great variability in joint orientation angles on the coronal plane; the whole lower limb alignment and the femur, tibia, and joint were more valgus in knees with RA than with OA.

Ultrasound detects synovitis in replaced and other surgically operated joints in rheumatoid arthritis patients

Background

Joint replacements continue to occur during a rheumatoid arthritis (RA) patient’s lifetime despite significant advances in available treatment options. The purpose of this study was to examine and quantify synovitis in surgically operated joints by ultrasound (US) in RA patients starting a new therapeutic agent.

Methods

RA subjects were enrolled in either tocilizumab or tofacitinib open-label, investigator-initiated trials and were assessed by ultrasound. In a subset of RA patients with joint replacements and/or operations of joint areas (OJA; e.g. joint arthroscopies, fusions, and synovectomies), joint-level scores of synovitis were compared between replaced joints, OJAs, and native joints. Joint-level synovitis was measured by grayscale (GSUS (0–3)) and power Doppler (PDUS (0–3)) at baseline and follow-up (3–6 months). McNemar’s test or Wilcoxon signed rank test utilized the mixed effects ordinal logistic regression models.

Results

Twenty RA patients had a total of 25 replaced joints and 24 OJA. All replaced joints had GSUS> 1 and 92% had PDUS> 1 at baseline, while OJA and native joints had lower evidence of GSUS> 1 (37.5, 38% respectively) and PDUS> 1 (45.8, 62% respectively). GSUS and PDUS semiquantitative scores improved significantly with treatment in replaced joints (p = 0.01, p = 0.007), and native joints (p < 0.001 both), but not OJA.

Conclusions

In RA, joint replacement does not eliminate or prevent ultrasound measured synovitis, where all replaced joints have some evidence of US synovitis. US can also act as a potential marker of response to therapy in replaced joints. Scoring US synovitis in replaced joints should be considered in ultrasound RA clinical trials.

Trial registration

ClinicalTrials.gov NCT01717859 (registered 10/31/2012); ClinicalTrials.gov NCT02321930 (registered 12/22/2014).

Axillary lymph-node metabolic activity assessment on 18F-FDG-PET/CT in rheumatoid arthritis patients treated with biologic therapies

Objective: Recent studies have provided new insights into the role of lymph nodes (LNs) in rheumatoid arthritis (RA). The aim of this study was to evaluate the metabolic activity of the axillary LNs in relation to that of the upper limb joints and the clinical assessment of disease activity in RA patients treated with biologic therapies.Method: ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) scans were acquired for 64 patients with RA at baseline and after 6 months of biologic therapy, and the patients' clinical status was evaluated. The maximum standardized uptake value (SUV_max), metabolic active volume, and total lesion glycolysis (TLG) were used to assess glucose metabolism in the LNs and 12 joints. Clinical evaluations included serum markers and the Disease Activity Score based on 28-joint count-erythrocyte sedimentation rate (DAS28-ESR).Results: Changes in the SUV_max and TLG for the axillary LNs correlated significantly with those of the ipsilateral wrist joints. There was a positive correlation between the changes in the three metabolic parameters of the axillary LNs and the changes in disease activity after treatment. After 6 months of biologic therapy, all metabolic parameters for the axillary LNs in patients with a DAS28-ESR < 3.2 were significantly lower than those of patients with a DAS28-ESR ≥ 3.2.Conclusion: A relationship between the glucose metabolism of the axillary LNs and the ipsilateral wrist joints was demonstrated by the ¹⁸F-FDG-PET/CT parameters. The metabolic activity and active volume of axillary LNs may reflect the therapeutic response to the biologic treatment of RA.

Long-term patient reported outcomes of elbow, wrist and hand surgery for rheumatoid arthritis

AIM

A retrospective questionnaire survey was conducted to investigate the long-term outcomes of elbow, wrist and hand surgery for rheumatoid arthritis (RA).

METHODS

One hundred and thirteen RA patients underwent primary elective elbow, wrist or hand surgery at our hospital between January 2002 and December 2003. To evaluate the outcomes at 10 years after surgery, the patient-reported outcomes were assessed using an original questionnaire that inquired about the site of treatment; the modified Stanford Health Assessment Questionnaire (mHAQ) was also used.

RESULTS

Responses were obtained from 67 patients (98 sites). In the 10 years after surgery, the Disease Activity Score of 28 joint - erythrocyte sedimentation rate (4) and the modified Health Assessment Questionnaire scores of the patients showed significant improvement. Nearly 85% of patients were satisfied with the outcome at the surgical site. The most frequent reason for perceived improvement was 'pain relief' (all surgical sites). An 'improved appearance' was frequently reported after finger surgery and 'increased power' was frequently reported after wrist and thumb surgeries. With regard to elbow surgery, 30% of the patients were satisfied with the increase in motion and power. In contrast, approximately 20% of patients complained of decreased power around the surgical site after elbow and thumb surgeries.

CONCLUSIONS

Our original patient-reported outcome assessment tool revealed that elbow, wrist and hand surgery provided long-lasting benefits in RA patients. While the efficacy differed in some of the surgical sites, pain relief was the most favorable effect. Altered medical therapy may also have impacted the patient-perceived outcomes of surgery at 10 years.

Total knee arthroplasty improves both knee function and disease activity in patients with rheumatoid arthritis

OBJECTIVE

This study evaluated the effect of TKA with capsulosynovectomy on disease activity and knee function in patients with RA.

METHODS

Seventy-six RA patients who underwent primary TKA with more than two years of follow-up were retrospectively reviewed to assess postoperative knee function and disease activity.

RESULTS

Postoperative knee function was significantly improved in all clinical scores, and maintained up to 24 months after surgery. RA disease activity was significantly decreased in DAS28-CRP, CDAI, and serum CRP level, and maintained up to 24 months after surgery. Postoperative knee function was negatively correlated with RA disease activity.

CONCLUSIONS

TKA improves both knee function and disease activity in patients with rheumatoid arthritis.