Primer: pitfalls of aspiration and injection

Clinical examination, ultrasound assessment and aspiration of knee effusion in primary knee osteoarthritis patients

BACKGROUND

To assess the diagnostic performance of clinical examination and ultrasound (US) assessment of knee effusion in primary knee osteoarthritis (KOA) patients. Furthermore, the success rate for effusion aspiration and the factors related to it were investigated.

METHODS

This cross-sectional study included patients diagnosed with primary KOA-induced knee effusion clinically or sonographically. The affected knee of each patient was subjected to clinical examination and US assessment using the ZAGAZIG effusion and synovitis ultrasonographic score. Patients with confirmed effusion and consented to aspiration were prepared for direct US-guided aspiration under complete aseptic techniques.

RESULTS

One hundred and nine knees were examined. During visual inspection, swelling was detected in 80.7% of knees and effusion was confirmed by US in 67.8% of knees. Visual inspection was the most sensitive at 90.54% while bulge sign was the most specific at 65.71%. Only 48 patients (61 knees) consented to aspiration procedure; 47.5% had grade III effusion, and 45.9% had grade III synovitis. Successful aspiration was achieved in 77% of knees. Two needle types were used; a 22 gauge / 3.5-inch spinal needle in 44 knees and an 18 gauge/ 1.5-inch needle in 17 knees, with a success rate of 90.9% and 41.2%, respectively. Aspirated amount of synovial fluid correlated positively with effusion grade (r_s=0.455, p < 0.001) and negatively with synovitis grade on US (r_s = - 0.329, p = 0.01).

CONCLUSIONS

The superiority of the US over clinical examination in detecting knee effusion suggests that US should be used routinely to confirm the presence of effusion. Long needles (spinal needle) may have a higher success rate of aspiration than shorter needles.

Likelihood of hip infection with image-guided hip aspiration dry tap: a 10-year retrospective study

OBJECTIVE

To determine the rate of infection in patients with suspected hip septic arthritis who underwent image-guided aspiration (IHA) resulting in dry-tap, diagnostic value of subsequent lavage and re-aspiration, and if pre-aspiration MRI can help prevent a dry tap.

MATERIALS AND METHODS

Retrospective review between 2010 to 2020 identified native hip (NH) and total hip arthroplasty (THA) patients who had a dry-tap following aspiration for suspected infection or periprosthetic joint infection (PJI). Serology tests, lavage/re-aspiration volumes, and aspirate cell-count/culture were assessed. On pre-aspiration MRI, presence/grade of joint effusion (JE), pseudocapsule dehiscence (PD), extraarticular fluid and sinus-tract were recorded.

RESULTS

Out of 215 included dry-taps, 185 (86.0%) were non-infected and 30 (13.9%) infected. In subgroup analysis, 64/71(90.1%) NH and 121/144(84.0%) THA dry-taps were non-infected. Pre-aspiration MRI of THA group with dry-tap showed significant findings; PD with extraarticular fluid (8/12, 66.7%) and sinus tract (7/12, 58.3%) were higher in the infected compared to non-infected group (5/42, 11.9% and 0/42, 0.0%) (both p < 0.001). Among THA group, polymorphonuclear-leukocytes > 80% was present in 8/9 (88.9%) of infected versus 4/28 (14.3%) non-infected group (p < 0.001). Multivariable regression showed PD (p = 0.005) and JE (p = 0.042) being significant independent predictors of PJI, similarly the elevated CRP (p = 0.044) and JE (p = 0.017).

CONCLUSION

Majority of patients suspected of hip joint infection with dry-tap were non-infected. Synovial PMN% following lavage maintains high sensitivity for detection of PJI. In patients with THA, PD and subsequent extraarticular collection can be associated with dry-tap therefore, pre-aspiration MRI can help determine their presence and plan the aspiration.

Enhanced arthrocentesis of the effusive knee with pneumatic compression

AIM

Complete arthrocentesis of the effusive knee ameliorates patient pain, reduces intra-articular and intraosseous pressure, removes inflammatory cytokines, and has been shown to substantially improve the therapeutic outcomes of intra-articular injections. However, conventional arthrocentesis incompletely decompresses the knee, leaving considerable residual synovial fluid in the intra-articular space. The present study determined whether external pneumatic circumferential compression of the effusive knee permitted more successful arthrocentesis and complete joint decompression.

METHODS

Using a paired sample design, 50 consecutive effusive knees underwent conventional arthrocentesis and then arthrocentesis with pneumatic compression. Pneumatic compression was applied to the superior knee using a conventional thigh blood pressure cuff inflated to 100 mm Hg which compressed the suprapatellar bursa and patellofemoral joint, forcing fluid from the superior knee to the anterolateral portal where the fluid could be accessed. Arthrocentesis success and fluid yield in mL before and after pneumatic compression were determined.

RESULTS

Successful diagnostic arthrocentesis (≥3 mL) of the effusive knee was 82% (41/50) with conventional arthrocentesis and increased to 100% (50/50) with pneumatic compression (P = .001). Synovial fluid yields increased by 144% (19.8 ± 17.1 mL) with pneumatic compression (conventional arthrocentesis; 13.7 ± 16.4 mL, pneumatic compression: 33.4 ± 26.5 mL; 95% CI: 10.9 < 19.7 < 28.9 mL, P < .0001).

CONCLUSIONS

Conventional arthrocentesis routinely does not fully decompress the effusive knee. External circumferential pneumatic compression markedly improves arthrocentesis success and fluid yield, and permits complete decompression of the effusive knee. Pneumatic compression of the effusive knee with a thigh blood pressure cuff is an inexpensive and widely available technique to improve arthrocentesis outcomes.

Can Diagnostic and Therapeutic Arthrocentesis Be Successfully Performed in the Flexed Knee?

BACKGROUND/OBJECTIVE

The objective of this study was to determine whether the extended or flexed knee positioning was superior for arthrocentesis and whether the flexed knee positioning could be improved by mechanical compression.

METHODS

Fifty-five clinically effusive knees underwent arthrocentesis in a quality improvement intervention: 20 consecutive knees in the extended knee position using the superolateral approach, followed by 35 consecutive knees in the flexed knee position with and without an external compression brace placed on the suprapatellar bursa. Arthrocentesis success and fluid yield in milliliters were measured.

RESULTS

Fluid yield for the extended knee was greater (191% greater) than the flexed knee (extended knee, 16.9 ± 15.7 mL; flexed knee, 5.8 ± 6.3 mL; P < 0.007). Successful diagnostic arthrocentesis (≥2 mL) was 95% (19/20) in the extended knee and 77% (27/35) in the flexed knee (P = 0.08). After mechanical compression was applied to the suprapatellar bursa and patellofemoral joint of the flexed knee, fluid yields were essentially identical (extended knee, 16.9 ± 15.7 mL; flexed knee, 16.7 ± 11.3 mL; P = 0.73), as were successful diagnostic arthrocentesis (≥2 mL) (extended knee 95% vs. flexed knee 100%, P = 0.12).

CONCLUSIONS

The extended knee superolateral approach is superior to the flexed knee for conventional arthrocentesis; however, the extended knee positioning and flexed knee positioning have identical arthrocentesis success when mechanical compression is applied to the superior knee. This new flexed knee technique for arthrocentesis is a useful alternative for patients who are in wheelchairs, have flexion contractures, cannot be supine, or cannot otherwise extend their knee.

Extractable synovial fluid in inflammatory and non-inflammatory arthritis of the knee

INTRODUCTION/OBJECTIVES

We hypothesized that mechanical compression of the knee in rheumatoid arthritis (RA) would mobilize occult extractable fluid and improve arthrocentesis success.

METHODS

Sixty-seven consecutive knees with RA and 186 knees with OA and were included. Conventional arthrocentesis was performed and success and volume (milliliters) determined; the needle was left intraarticularly, and mechanical compression was applied with an elastomeric knee brace. Arthrocentesis was then resumed until fluid return ceased. Fluid was characterized as to volume and cell counts.

RESULTS

In the RA, knee mechanical compression decreased failed diagnostic arthrocentesis from 56.7% (38/67) to 26.9% (18/67) (- 47.4%, p = 0.003) and increased absolute arthrocentesis yield from 4.7 ± 10.3 ml to 9.8 ± 9.8 ml (108% increase, 95% CI - 8.5 < - 5.1 < - 1.7 p = 0.0038). Total extractable fluid yield was 96% greater in RA (9.8 ± 9.8 ml) than OA (5.0 ± 9.4 ml, p = 0.0008), and occult extractable fluid was 77% greater in RA than OA (RA 5.3 ± 8.7 ml, OA 3.0 ± 5.5 ml, p = 0.046). Large effusions versus small effusions in RA demonstrated increased neutrophils in synovial fluid (p = 0.04) but no difference in radiologic arthritis grade (p = 0.87). In contrast, large effusions versus small effusions in OA demonstrated no difference in neutrophils in synovial fluid (p = 0.87) but significant different radiologic arthritis grade (p = 0.04).

CONCLUSION

Mechanical compression improves the success of diagnostic and therapeutic knee arthrocentesis in both RA and OA. Large effusions in RA are associated with increased neutrophil counts but not arthritis grade; in contrast, large effusions in OA are associated with more severe arthritis grades but not increased neutrophil counts. Key points• Mechanical compression of the painful knee improves arthrocentesis success and fluid yield in both rheumatoid arthritis and osteoarthritis.• The painful rheumatoid knee contains approximately 100% more fluid than the osteoarthritic knee.• Large effusions in the osteoarthritic knee are characterized by higher grades of mechanical destruction but not increased neutrophil counts.• In contrast, large effusions in the rheumatoid knee are characterized by higher synovial fluid neutrophil counts but not the grade of mechanical destruction, indicating different mechanisms of effusion formation in rheumatoid arthritis versus osteoarthritis.

Evaluation and Management of Septic Arthritis and its Mimics in the Emergency Department

Septic arthritis is a dangerous medical condition associated with significant morbidity and mortality. However, the differential diagnosis can be broad with conditions that mimic this disease and require different evaluation and treatment. This narrative review presents the emergency medicine evaluation and management, as well as important medical conditions that may mimic this disease. Septic arthritis commonly presents with monoarticular joint pain with erythema, warmth, swelling, and pain on palpation and movement. Fever is present in many patients, though most are low grade. Blood testing and imaging may assist with the diagnosis, but the gold standard is joint aspiration. Management includes intravenous antibiotics and orthopedic surgery consult for operative management vs. serial aspirations. Clinicians should consider mimics, such as abscess, avascular necrosis, cellulitis, crystal-induced arthropathies, Lyme disease, malignancy, osteomyelitis, reactive arthritis, rheumatoid arthritis, and transient synovitis. While monoarticular arthritis can be due to septic arthritis, other medical and surgical conditions present similarly and require different management. It is essential for the emergency clinician to be aware how to diagnose and treat these mimics.

Improvement in diagnostic and therapeutic arthrocentesis via constant compression

We hypothesized that constant compression of the knee would mobilize residual synovial fluid and promote successful arthrocentesis. Two hundred and ten knees with grade II-III osteoarthritis were included in this paired design study: (1) conventional arthrocentesis was performed with manual compression and success and volume (milliliters) determined; and (2) the intra-articular needle was left in place, and a circumferential elastomeric brace was tightened on the knee to provide constant compression. Arthrocentesis was attempted again and additional fluid volume was determined. Diagnostic procedural cost-effectiveness was determined using 2017 US Medicare costs. No serious adverse events were noted in 210 subjects. In the 158 noneffusive (dry) knees, sufficient synovial fluid for diagnostic purposes (≥ 2 ml) was obtained in 5.0% (8/158) without compression and 22.8% (36/158) with compression (p = 0.0001, z for 95% CI = 1.96), and the absolute volume of arthrocentesis fluid obtained without compression was 0.28 ± 0.79 versus 1.10 ± 1.81 ml with compression (293% increase, p = 0.0001). In the 52 effusive knees, diagnostic synovial fluid (≥ 2 ml) was obtained in 75% (39/52) without compression and 100% (52/52) with compression (p = 0.0001, z for 95% CI = 1.96), and the absolute volume of arthrocentesis without compression was 14.7 ± 13.8 versus 25.3 ± 15.5 ml with compression (72.1% increase, p = 0.0002). Diagnostic procedural cost-effectiveness was $655/sample without compression and $387/sample with compression. The new technique of constant compression via circumferential mechanical compression mobilizes residual synovial fluid beyond manual compression improving the success, cost-effectiveness, and yield of diagnostic and therapeutic arthrocentesis in both the effusive and noneffusive knee.

An Accurate Full-flexion Anterolateral Portal for Needle Placement in the Knee Joint With Dry Osteoarthritis

INTRODUCTION

Accurate delivery of an injection into the intra-articular space of the knee is achieved in only two thirds of knees when using the standard anterolateral portal. The use of a modified full-flexion anterolateral portal provides a highly accurate, less painful, and more effective method for reproducible intra-articular injection without the need for ultrasonographic or fluoroscopic guidance in patients with dry osteoarthritis of the knee.

METHODS

The accuracy of needle placement was assessed in a prospective series of 140 consecutive injections in patients with symptomatic degenerative knee arthritis without clinical knee effusion. Procedural pain was determined using the Numerical Rating Scale. The accuracy rates of needle placement were confirmed with fluoroscopic imaging to document the dispersion pattern of injected contrast material.

RESULTS

Using the standard anterolateral portal, 52 of 70 injections were confirmed to have been placed in the intra-articular space on the first attempt (accuracy rate, 74.2%). Using the modified full-flexion anterolateral portal, 68 of 70 injections were placed in the intra-articular space on the first attempt (accuracy rate, 97.1%; P = 0.000).

CONCLUSION

This study revealed that using the modified full-flexion anterolateral portal for injections into the knee joint resulted in more accurate and less painful injections than those performed by the same orthopaedic surgeon using the standard anterolateral portal. In addition, the technique offered therapeutic delivery into the joint without the need for fluoroscopic confirmation.

LEVEL OF EVIDENCE

Therapeutic Level II.

Effectiveness of Ultrasound Guidance on Intraarticular and Periarticular Joint Injections: Systematic Review and Meta-analysis of Randomized Trials

OBJECTIVE

The aim of this study was to evaluate the effectiveness and accuracy of ultrasound-guided intraarticular and periarticular joint injections as compared with landmark-guided injections technique.

METHODS

A systematic literature search was performed in Medline, Web of Science, Embase, the Cochrane Central Register of Controlled Trials, reference lists of articles, and other sources. Only randomized controlled trials were included. Two reviewers independently selected and assessed each study for quality and extracted data.

RESULTS

Twelve randomized controlled trials were included in the meta-analysis. The results indicated that ultrasound-guided intraarticular and periarticular joint injections were more accurate than the landmark-guided injections (odds ratio, 0.36; 95% confidence interval, 0.22-0.60). Ultrasound-guided joint injections significantly decreased the visual analog scale scores at both 2 wks (mean difference, -9.57; 95% confidence interval, -13.14 to -5.99) (P < 0.00001) and 6 wks (mean difference, -14.21; 95% confidence interval, -18.20 to -10.21) (P < 0.00001) after injection. There was no statistically significant difference in visual analog scale score at 12 wks between ultrasound-guided and landmark-guided intraarticular and periarticular joint injections (mean difference, -4.42; 95% confidence interval, -11.71 to 2.87) (P = 0.23).

CONCLUSIONS

Intraarticular and periarticular injections using ultrasound guidance significantly improves the accuracy of joint injections, and there is a significant decrease in visual analog scale scores for up to 6 wks after injection. The effect of ultrasound guidance on the long-term outcome of joint injections is inconclusive. The improved accuracy of injections was associated with pain relief. The authors recommend routine ultrasound guidance for intraarticular and periarticular injections.

Predictors of response to intra-articular steroid injections in knee osteoarthritis--a systematic review

OBJECTIVE

IA steroid injections (IASIs) have been shown to relieve pain in knee OA and are widely used in clinical practice. There is, however, evidence of some variation in response. Knowledge of predictors of response could aid in the selection of patients for this therapy. The aim of this systematic review was to determine factors associated with response to IASI in knee OA.

METHODS

Medline, Embase, AMED, CINAHL, Web of Science and Cochrane Central Registers for Controlled Trials up to January 2012 were searched with additional hand searches of relevant articles. Studies included were those that involved adults diagnosed with knee OA in whom IASIs were administered and factors that predicted treatment response were investigated.

RESULTS

Eleven publications meeting these criteria were reviewed and relevant information extracted. It was not possible to pool the results because of the different predictors studied, variable outcome measures, different criteria for symptom change and missing data. Given the relative paucity of data and small heterogeneously designed studies, it was difficult to identify predictors of response. Data from individual publications, although not consistent across studies, suggest that the presence of effusion, withdrawal of fluid from the knee, severity of disease, absence of synovitis, injection delivery under US guidance and greater symptoms at baseline may all improve the likelihood of response to IASI.

CONCLUSION

Further larger-scale studies using standardized methods are required to characterize predictors of response and should focus on synovitis, effusion, pain and structural severity of disease. Such data would help in better targeting therapy to those most likely to benefit.

A randomized controlled trial evaluating the cost-effectiveness of sonographic guidance for intra-articular injection of the osteoarthritic knee

OBJECTIVE

The present randomized controlled study investigated whether sonographic needle guidance affected the outcomes of intra-articular injection for osteoarthritis of the knee.

METHODS

Ninety-four noneffusive knees with osteoarthritis were randomized to injection by conventional palpation-guided anatomic landmark injection or sonographic image-guided injection enhanced with a 1-handed mechanical (the reciprocating procedure device) syringe. After intra-articular placement and synovial space dilation were confirmed by sonography, a syringe exchange was performed, and 80 mg of triamcinolone acetonide was injected with the second syringe through the indwelling intra-articular needle. Baseline pain, procedural pain, pain at outcome (2 weeks and 6 months), responders, therapeutic duration, reinjection rates, total cost, and cost per responder were determined.

RESULTS

Relative to conventional palpation-guided anatomic landmark methods, sonographic guidance for injection of the knee resulted in 48% reduction in procedural pain (P < 0.001), a 42% reduction in pain scores at outcome (P < 0.03), 107% increase in the responder rate (P < 0.001), 52% reduction in the nonresponder rate (P < 0.001), a 36% increase in therapeutic duration (P = 0.01), a 13% reduction ($17) in cost per patient per year, and a 58% ($224) reduction in cost per responder per year for a hospital outpatient (P < 0.001).

CONCLUSIONS

Sonographic needle guidance reduced procedural pain and improved the clinical outcomes and cost-effectiveness of intra-articular injections of the osteoarthritic knee.

Does ultrasound guidance improve the outcomes of arthrocentesis and corticosteroid injection of the knee?

OBJECTIVE

The present randomized controlled trial compared arthrocentesis of the effusive knee followed by corticosteroid injection performed by the conventional anatomic landmark palpation-guided technique to the same procedure performed with ultrasound (US) needle guidance.

METHODS

Sixty-four palpably effusive knees were randomized to (i) palpation-guided arthrocentesis with a conventional 20-mL syringe (22 knees), (ii) US-guided arthrocentesis with a 25-mL reciprocating procedure device (RPD) mechanical aspirating syringe (22 knees), or (iii) US-guided arthrocentesis with a 60-mL automatic aspirating syringe (20 knees). The one-needle two-syringe technique was used. Outcome measures included patient pain by the Visual Analogue Scale (VAS) for pain (0-10 cm), the proportion of diagnostic samples, synovial fluid volume yield, complications, and therapeutic outcome at 2 weeks.

RESULTS

Sonographic guidance resulted in 48% less procedural pan (VAS; palpation-guided: 5.8 ± 3.0 cm, US-guided: 3.0 ± 2.8 cm, p < 0.001), 183% increased aspirated synovial fluid volumes (palpation-guided: 12 ± 10 mL, US-guided: 34 ± 25 mL, p < 0.0001), and improved outcomes at 2 weeks (VAS; palpation-guided: 2.8 ± 2.4 cm, US-guided: 1.5 ± 1.9 cm, p = 0.034). Outcomes of sonographic guidance with the mechanical syringe and automatic syringe were comparable in all outcome measures.

CONCLUSIONS

US-guided arthrocentesis and injection of the knee are superior to anatomic landmark palpation-guided arthrocentesis, resulting in significantly less procedural pain, improved arthrocentesis success, greater synovial fluid yield, more complete joint decompression, and improved clinical outcomes.

The highly accurate anteriolateral portal for injecting the knee

Background

The extended knee lateral midpatellar portal for intraarticular injection of the knee is accurate but is not practical for all patients. We hypothesized that a modified anteriolateral portal where the synovial membrane of the medial femoral condyle is the target would be highly accurate and effective for intraarticular injection of the knee.

Methods

83 subjects with non-effusive osteoarthritis of the knee were randomized to intraarticular injection using the modified anteriolateral bent knee versus the standard lateral midpatellar portal. After hydrodissection of the synovial membrane with lidocaine using a mechanical syringe (reciprocating procedure device), 80 mg of triamcinolone acetonide were injected into the knee with a 2.0-in (5.1-cm) 21-gauge needle. Baseline pain, procedural pain, and pain at outcome (2 weeks and 6 months) were determined with the 10 cm Visual Analogue Pain Score (VAS). The accuracy of needle placement was determined by sonographic imaging.

Results

The lateral midpatellar and anteriolateral portals resulted in equivalent clinical outcomes including procedural pain (VAS midpatellar: 4.6 ± 3.1 cm; anteriolateral: 4.8 ± 3.2 cm; p = 0.77), pain at outcome (VAS midpatellar: 2.6 ± 2.8 cm; anteriolateral: 1.7 ± 2.3 cm; p = 0.11), responders (midpatellar: 45%; anteriolateral: 56%; p = 0.33), duration of therapeutic effect (midpatellar: 3.9 ± 2.4 months; anteriolateral: 4.1 ± 2.2 months; p = 0.69), and time to next procedure (midpatellar: 7.3 ± 3.3 months; anteriolateral: 7.7 ± 3.7 months; p = 0.71). The anteriolateral portal was 97% accurate by real-time ultrasound imaging.

Conclusion

The modified anteriolateral bent knee portal is an effective, accurate, and equivalent alternative to the standard lateral midpatellar portal for intraarticular injection of the knee.

Trial Registration

ClinicalTrials.gov: NCT00651625

The outcomes and cost-effectiveness of intraarticular injection of the rheumatoid knee

Although intraarticular injections are important to the management of rheumatoid arthritis, there are few studies regarding the cost-effectiveness of alternative injection techniques. This randomized controlled study addressed the cost-effectiveness of two different low-cost, anatomic landmark palpation-directed intraarticular injection techniques. Ninety-six symptomatic rheumatoid knees were randomized to two different low-cost, palpation-guided intraarticular injection techniques utilizing (1) a conventional syringe or (2) a mechanical syringe, the RPD (the reciprocating procedure device). Three milliliters of 1% lidocaine were used to anesthetize the synovial membrane, followed by arthrocentesis and hydrodissection, and injection of 80 mg of triamcinolone acetonide utilizing the one-needle two-syringe technique. Baseline pain, procedural pain, aspirated fluid volume, pain at outcome (2 weeks and 6 months), responders, reinjection rates, cost/patient/year, and cost/responder/year were determined. Pain was measured with the 10 cm Visual Analogue Pain Scale (VAS). Both techniques significantly reduced pain scores at outcome from baseline (P < 0.001). The mechanical syringe technique resulted in a greater volume of aspirated fluid (P < 0.01), a 38% reduction in procedural pain (P < 0.001), a 24% reduction in pain scores at outcome (P < 0.03), an increase in the responder rate (P < 0.025), 33% increase in the time to next injection (P < 0.001), 23% ($35 US) reduction in cost/patient/year for a patient treated in a physician office (P < 0.001), 24% reduction ($26 US) in cost/patient/year for a hospital outpatient (P < 0.001), and 51% ($151 US) reduction in cost/responder/year (P < 0.001). The outcomes and cost-effectiveness of intraarticular injection of the rheumatoid knee can be improved significantly with low-cost alternations in technique.

A Randomized Controlled Trial of the Cost-Effectiveness of Ultrasound-Guided Intraarticular Injection of Inflammatory Arthritis

Objective.

We studied whether sonographic needle guidance affected the outcomes of intraarticular (IA) injection for inflammatory arthritis.

Methods.

Joints with inflammatory arthritis (n = 244; 76% rheumatoid arthritis, 3% small joints, 51% intermediate, and 46% large) were randomized to injection by conventional palpation-guided anatomic injection (120 joints) or sonographic image-guided injection enhanced with a 1-handed reciprocating procedure device mechanical syringe (124 joints). A 1-needle, 2-syringe technique was used. After IA placement and synovial space dilation were confirmed by sonography, a syringe exchange was performed, and triamcinolone acetonide was injected with the second syringe through the indwelling IA needle. Baseline pain, procedural pain, pain at outcome (2 weeks and 6 months), responders, therapeutic duration, reinjection rates, total cost, and cost per responder were determined.

Results.

Relative to conventional palpation-guided methods, sonographic guidance for injection of inflammatory arthritis resulted in an 81% reduction in injection pain (p < 0.001), 35% reduction in pain scores at outcome (p < 0.02), 38% increase in the responder rate (p < 0.003), 34% reduction in the non-responder rate (p < 0.003), 32% increase in therapeutic duration (p = 0.01), 8% reduction ($7) in cost/patient/year, and a 33% ($64) reduction in cost/responder/year for a hospital outpatient (p < 0.001).

Conclusion.

Sonographic needle guidance improves the performance, clinical outcomes, and cost-effectiveness of IA injections for inflammatory arthritis. (Clinical Trial Identifier NCT00651625)