Patterns of intra-articular injection use after initiation of treatment in patients with knee osteoarthritis: data from the osteoarthritis initiative

Intra-articular delivery of flurbiprofen sustained release thermogel: improved therapeutic outcome of collagenase II-induced rat knee osteoarthritis

Knee osteoarthritis (OA) is a common degenerative disease. Intra-articular administration of flurbiprofen is frequently employed in clinic to treat OA, while repeated injections are required because of the limited effective duration. To improve therapeutic outcome and prolong the treatment interval, a poly(ε-caprolactone-co-lactide)-b-poly(ethylene glycol)-b-poly(ε-caprolactone-co-lactide) (PCLA-PEG-PCLA) triblock copolymer based flurbiprofen thermosensitive gel for the sustained intra-articular drug delivery was designed in this study. The anti-OA effects of this flurbiprofen thermogel were investigated on collagenase II-induced rat knee OA model by multiple approaches and compared with that of conventional sodium hyaluronate and flurbiprofen injecta. In vitro drug release studies indicated that flurbiprofen was sustained released from the thermosensitive gel for more than three weeks. This sustained drug release system exerted comparable short-term analgesic effects and distinctly improved long-term analgesic efficacy in terms of the increased percentage of the total ipsilateral paw print intensity and the reduced Knee-Bend scores of OA rats. The inflammatory response was attenuated in the samples of flurbiprofen gel treated group by showing decreased IL-1, IL-6, and IL-11 levels in the joint fluid and down-regulated IL-1, IL-6, IL-11, COX-2, TNF-α, and NF-κB/p65 expression in the articular cartilages. The results suggest the suitability of thermosensitive copolymer PCLA-PEG-PCLA for sustained intra-articular effects of flurbiprofen and provide in vivo experimental evidence for potential clinical application of this flurbiprofen delivery system to better management of OA cases.

Intra-articular Corticosteroid Injections for Symptomatic Knee Osteoarthritis: What the Orthopaedic Provider Needs to Know

Intra-articular corticosteroid injections have been used for decades in the management of symptomatic osteoarthritis of the knee and remain a common practice. The pain relief from a steroid injection is thought to work by reducing inflammation within the arthritic knee. Substantial variability remains among providers with regard to the technique used to perform the procedure, including the site of the injection, the medications injected, and the level of sterility. The success of steroid injections in relieving arthritic knee pain most often occurs in the short term. However, the efficacy of intra-articular corticosteroid injections varies within the published literature. The latest American Academy of Orthopaedic Surgeons clinical practice guideline does not support conclusive recommendations about the use of intra-articular corticosteroid injections for symptomatic knee osteoarthritis. Providers should be aware of the adverse effects and potential complications of these injections when using them in clinical practice.

Missing Data in Marginal Structural Models: A Plasmode Simulation Study Comparing Multiple Imputation and Inverse Probability Weighting

BACKGROUND

The use of marginal structural models (MSMs) to adjust for time-varying confounding has increased in epidemiologic studies. However, in the setting of MSMs, recommendations for how best to handle missing data are contradictory. We present a plasmode simulation study to compare the validity and precision of MSMs estimates using complete case analysis (CC), multiple imputation (MI), and inverse probability weighting (IPW) in the presence of missing data on time-independent and time-varying confounders.

MATERIALS AND METHODS

Simulations were based on a cohort substudy using data from the Osteoarthritis Initiative which estimated the marginal causal effect of intra-articular injection use on yearly changes in knee pain. We simulated 81 scenarios with parameter values varied on missing mechanisms (MCAR, MAR, and MNAR), percentages of missing (10%, 20%, and 30%), type of confounders (time-independent, time-varying, either or both), and analytical approaches (CC, IPW, and MI). The performance of CC, IPW, and MI methods was compared using relative bias, mean squared error of the estimates of interest, and empirical power.

RESULTS

Across scenarios defined by missing data mechanism, extent of missing data, and confounder type, MI generally produced less biased estimates (range: 1.2%-6.7%) with better precision (range: 0.17-0.18) compared with IPW (relative bias: -5.3% to 8.0%; precision: 0.19-0.53). Empirical power was constant across the scenarios using MI.

CONCLUSIONS

Under simple yet realistically constructed scenarios, MI seems to confer an advantage over IPW in MSMs applications.

Single-dose intra-articular corticosteroid injection prior to platelet-rich plasma injection resulted in better clinical outcomes in patients with knee osteoarthritis: A pilot study

BACKGROUND

The synergistic and protective effect of platelet-rich plasma (PRP) added to methlyprednisolone (MP) has been demonstrated via in-vitro studies. However, there is no report in the literature about this issue.

OBJECTIVE

The aim of this study was to evaluate clinical outcomes of intra-articular (IA) MP injection prior to PRP injection in comparison with single-dose MP and PRP injections alone in patients with knee osteoarthritis (OA).

METHODS

The treatment groups were "PRP group" (n= 37) who underwent single-dose IA PRP injection, "PRP + MP group" (n= 40) who underwent MP injection one week prior to single-dose PRP injection, and "MP group" (n= 38) who underwent single-dose MP injection. Visual Analog Scale (VAS) and The Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were applied at first admission and at 1st, 3rd, 6th, and 12th month follow-ups.

RESULTS

At the end of the 1st month, WOMAC score in PRP + MP group was significantly lower than PRP group. At the 3rd month, WOMAC score in PRP + MP group was significantly lower than PRP and MP groups. At the 6th month, VAS and WOMAC score in PRP + MP group was significantly lower than MP group. At the end of the 12th month, no significant difference was observed among three groups in VAS and WOMAC scores.

CONCLUSION

According to our results, IA MP injection prior to PRP injection resulted in significantly better clinical outcomes compared to PRP and MP injections alone in patients who had mild to moderate knee OA.

Selection and Investigation of a Primate Model of Spontaneous Degenerative Knee Osteoarthritis, the Cynomolgus Monkey (Macaca Fascicularis)

BACKGROUND The aim of this study was to identify a primate model of degenerative knee osteoarthritis (KOA) that may be more relevant for research studies on degenerative KOA in humans. MATERIAL AND METHODS Sixteen specific-pathogen-free (SPF) male cynomolgus monkeys (Macaca fascicularis) were divided into group A (n=8), an old group (22.0-25.3 years of age), and group B (n=8), a young group (3.0-5.2 years of age). For each primate, the behavior was observed, knee circumference was measured, knee joint X-rays were performed, and peripheral blood white blood cell (WBC) counts were measured, and the Kellgren and Lawrence (K-L) system was used for the classification of osteoarthritis. An enzyme-linked immunoassay (ELISA) was performed on knee joint fluid to measure levels of interleukin (IL)-1β, transforming growth factor (TGF)-β1, and matrix metalloproteinase (MMP)13. Changes in articular cartilage were evaluated using the Brittberg score and the Mankin histopathology grading score, respectively. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western blot were used to measure the expression of the NOTCH3, JAG1, and ACAN genes in knee cartilage specimens, and the findings in the two groups of primates were compared. RESULTS Seven old aged primates in group A were compared with group B, and showed significant differences in WBC count, synovial fluid IL-1β, TGF-β1, and MMP13 levels, expression levels of the NOTCH3, JAG1, and ACAN genes in knee cartilage specimens, and in the Brittberg and Mankin scores (all, P<0.05). CONCLUSIONS Cynomolgus monkeys (Macaca fascicularis) might be a model for age-related degenerative KOA.

Longterm Effectiveness of Intraarticular Injections on Patient-reported Symptoms in Knee Osteoarthritis

OBJECTIVE

We examined the longterm effectiveness of corticosteroid or hyaluronic acid injections in relieving symptoms among persons with knee osteoarthritis (OA).

METHODS

Using Osteoarthritis Initiative data, a new-user design was applied to identify participants initiating corticosteroid or hyaluronic acid injections (n = 412). Knee symptoms (pain, stiffness, function) were measured using The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). We used marginal structural models adjusting for time-varying confounders to estimate the effect on symptoms of newly initiated injection use compared to nonusers over 2 years of followup.

RESULTS

Among 412 participants initiating injections, 77.2% used corticosteroid injections and 22.8% used hyaluronic acid injections. About 18.9% had additional injection use after initiation, but switching between injection types was common. Compared to nonusers, on average, participants initiating a corticosteroid injection experienced a worsening of pain (yearly worsening: 1.24 points, 95% CI 0.82-1.66), stiffness (yearly worsening: 0.30 points, 95% CI 0.10-0.49), and physical functioning (yearly worsening: 2.62 points, 95% CI 0.94-4.29) after adjusting for potential confounders with marginal structural models. Participants initiating hyaluronic acid injections did not show improvements of WOMAC subscales (pain: 0.50, 95% CI -0.11 to 1.11; stiffness: -0.07, 95% CI -0.38 to 0.24; and functioning: 0.49, 95% CI -1.34 to 2.32).

CONCLUSION

Although intraarticular injections may support the effectiveness of reducing symptoms in short-term clinical trials, the initiation of corticosteroid or hyaluronic acid injections did not appear to provide sustained symptom relief over 2 years of followup for persons with knee OA.