Increased frequency of acute local reaction to intra-articular hylan GF-20 (synvisc) in patients receiving more than one course of treatment

Inflammatory and immunological responses to hyaluronan preparations. Study of a murine biocompatibility model

BACKGROUND

Intra-articular injection of hyaluronan preparations is a popular treatment for osteoarthritis of the knee. Recently, clinical reports have described acute inflammatory reactions in joints following these injections. The purpose of this study was to use a murine pouch model to study the local inflammatory and possibly immunological effects of three commercially available hyaluronan-derived products.

METHODS

Each of three different hyaluronan products (Synvisc, Hyalgan, and Supartz) was injected into air pouches established in groups of BALB/c mice. A positive control group (with particle-induced inflammation) and a negative control group (injected with saline solution) were also included. After fourteen days, the mice were killed and the air pouches were explanted and prepared for histological evaluation of the local inflammatory reaction. The antibody response was measured with use of ELISA (enzyme-linked immunosorbent assay) of serum samples obtained after the mice were killed.

RESULTS

Histological analysis revealed a significant increase in total membrane cellularity (p < 0.001 to p < 0.03) after the use of all hyaluronan preparations. The increased cellularity was attributed to an inflammatory cell influx, rather than accumulation of fibroblasts, and elevated lymphocyte counts were observed in membranes stimulated by Synvisc (hylan G-F 20). The ELISA data revealed an antibody response to the Synvisc preparation. This immunological response was directed against a non-hyaluronan portion of the product, as indicated by the lack of cross-reactivity with the other hyaluronan products.

CONCLUSIONS

These findings demonstrate that all three hyaluronan preparations, as currently manufactured, can cause an inflammatory soft-tissue reaction, but only the non-hyaluronan portion of the Synvisc product created an immunological response. It appears likely that this component may be the target of adverse responses in patients.

Viscosupplementation therapy for osteoarthritis

Intra-articular viscosupplementation with hyaluronic acid has become an increasingly accepted therapeutic alternative in the symptomatic management of osteoarthritis. Basic science research has documented numerous potential actions of exogenous hyaluronic acid upon the diseased joint. A substantial aggregate of clinical data suggests that viscosupplementation is clinically safe and suggests some therapeutic efficacy with regard to pain relief. However, a robust placebo effect and industry bias have obscured these outcomes considerably. Although recent attention has focused on the disease-modifying potential of this treatment option, definitive evidence is lacking. This paper will review the development, experience, indications, and clinical outcomes of viscosupplementation therapy in patients with osteoarthritis.

Intra-articular distribution and residence time of Hylan A and B: a study in the goat knee

OBJECTIVE

This study evaluates the viscosupplementation material Hylan A and B in relation to its: (1) joint distribution, residence time and mechanism of removal and/or degradation, and (2) associated synovial fluid leukocyte response, in a goat model.

METHOD

One green fluorophore was covalently bound to the Hylan A low molecular weight (MW) molecule (viscous fluid fraction) and a second red fluorophore was covalently bound to Hylan B high MW molecule (globule gel-like fraction). Goats were anesthetized and the right knee received 0.5 ml of test material or unbound fluorophore dyes. Gross and histological serial evaluations were performed over an 8-week period.

RESULTS

By 24 h, the non-covalently linked control labels were not present in the tissues. For the covalently linked labels, the green fluorophore Hylan A diminished rapidly in intensity grossly but persisted to 28 days within the superficial synovial and articular cartilage layers in histologic sections. The red fluorophore linked Hylan B was seen only as globules in the synovial fluid. Mononuclear cells remained attached to these globules for 28 days and showed phagocytosis of the globules as well as the green fluorophore Hylan A. The globules were absent at 56 days after injection. The synovial fluid leukocyte count peaked at 24h (mean 9767 cells/mm(3) +/- 8574 S.D.) and declined by 7 days.

CONCLUSIONS

The smaller MW Hylan was removed more rapidly than the higher MW Hylan. The globules were degraded by a different mechanism involving monocytes/macrophages on the surface of the higher MW globules.

Therapeutic arthrography and bursography

Arthrography and bursography as therapeutic venues have found their place in the musculoskeletal procedure armamentarium. Therapeutic arthrography not only rules in and rules out the origin of pain but can provide 6 to 9 months of pain relief in diseased joints. Therapeutic arthrography allows injections of anesthetic, corticosteroid, or alternatively hyaluronic acid to be delivered accurately to the source of pain. Corticosteroids have a long history of use in osteoarthritis. Alternative therapy with hyaluronic acid is anew procedure. This article reviews the technique of arthrography in different joints and bursae and discusses the pros and cons of the use of corticosteroids versus viscosupplementation in therapeutic arthrography.

Viscosupplementation for the treatment of osteoarthritis of the knee

BACKGROUND

Osteoarthritis (OA) is the most prevalent chronic joint disorder worldwide and is associated with significant pain and disability.

OBJECTIVES

To assess the effects of viscosupplementation in the treatment of OA of the knee. The products were hyaluronan and hylan derivatives (Adant, Arthrum H, Artz (Artzal, Supartz), BioHy (Arthrease, Euflexxa, Nuflexxa), Durolane, Fermathron, Go-On, Hyalgan, Hylan G-F 20 (Synvisc Hylan G-F 20), Hyruan, NRD-101 (Suvenyl), Orthovisc, Ostenil, Replasyn, SLM-10, Suplasyn, Synject and Zeel compositum).

SEARCH STRATEGY

MEDLINE (up to January (week 1) 2006 for update), EMBASE, PREMEDLINE, Current Contents up to July 2003, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched. Specialised journals and reference lists of identified randomised controlled trials (RCTs) and pertinent review articles up to December 2005 were handsearched.

SELECTION CRITERIA

RCTs of viscosupplementation for the treatment of people with a diagnosis of OA of the knee were eligible. Single and double-blinded studies, placebo-based and comparative studies were eligible. At least one of the four OMERACT III core set outcome measures had to be reported (Bellamy 1997).

DATA COLLECTION AND ANALYSIS

Each trial was assessed independently by two reviewers for its methodological quality using a validated tool. All data were extracted by one reviewer and verified by a second reviewer . Continuous outcome measures were analysed as weighted mean differences (WMD) with 95% confidence intervals (CI). However, where different scales were used to measure the same outcome, standardized mean differences (SMD) were used. Dichotomous outcomes were analyzed by relative risk (RR).

MAIN RESULTS

Seventy-six trials with a median quality score of 3 (range 1 to 5) were identified. Follow-up periods varied between day of last injection and eighteen months. Forty trials included comparisons of hyaluronan/hylan and placebo (saline or arthrocentesis), ten trials included comparisons of intra-articular (IA) corticosteroids, six trials included comparisons of nonsteroidal anti-inflammatory drugs (NSAIDs), three trials included comparisons of physical therapy, two trials included comparisons of exercise, two trials included comparisons of arthroscopy, two trials included comparisons of conventional treatment, and fifteen trials included comparisons of other hyaluronans/hylan. The pooled analyses of the effects of viscosupplements against 'placebo' controls generally supported the efficacy of this class of intervention. In these same analyses, differential efficacy effects were observed for different products on different variables and at different timepoints. Of note is the 5 to 13 week post injection period which showed a percent improvement from baseline of 28 to 54% for pain and 9 to 32% for function. In general, comparable efficacy was noted against NSAIDs and longer-term benefits were noted in comparisons against IA corticosteroids. In general, few adverse events were reported in the hyaluronan/hylan trials included in these analyses.

AUTHORS' CONCLUSIONS

Based on the aforementioned analyses, viscosupplementation is an effective treatment for OA of the knee with beneficial effects: on pain, function and patient global assessment; and at different post injection periods but especially at the 5 to 13 week post injection period. It is of note that the magnitude of the clinical effect, as expressed by the WMD and standardised mean difference (SMD) from the RevMan 4.2 output, is different for different products, comparisons, timepoints, variables and trial designs. However, there are few randomised head-to-head comparisons of different viscosupplements and readers should be cautious, therefore, in drawing conclusions regarding the relative value of different products. The clinical effect for some products, against placebo, on some variables at some timepoints is in the moderate to large effect-size range. Readers should refer to relevant tables to review specific detail given the heterogeneity in effects across the product class and some discrepancies observed between the RevMan 4.2 analyses and the original publications. Overall, the analyses performed are positive for the HA class and particularly positive for some products with respect to certain variables and timepoints, such as pain on weight bearing at 5 to 13 weeks postinjection. In general, sample-size restrictions preclude any definitive comment on the safety of the HA class of products; however, within the constraints of the trial designs employed no major safety issues were detected. In some analyses viscosupplements were comparable in efficacy to systemic forms of active intervention, with more local reactions but fewer systemic adverse events. In other analyses HA products had more prolonged effects than IA corticosteroids. Overall, the aforementioned analyses support the use of the HA class of products in the treatment of knee OA.

A double-blind randomized controlled trial comparing alternate forms of high molecular weight hyaluronan for the treatment of osteoarthritis of the knee

OBJECTIVE

To compare the safety and effectiveness of a high molecular weight hyaluronan produced by biological fermentation (Bio-HA) with those of avian-derived hyaluronan that uses cross-linking to achieve high molecular weight (CL-HA).

DESIGN

This was a prospective, multicenter, randomized, double-blind trial evaluating patients with confirmed osteoarthritis of the knee. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC Index) pain subscale was the primary effectiveness measure (visual analog scale). Both products were administered via three weekly injections, with follow-up evaluations at weeks 3, 6 and 12. Acetaminophen was permitted as rescue medication and quantitated by pill counts.

RESULTS

Analyses were performed on the intent-to-treat population, defined as all patients receiving at least one injection. Of the 321 patients randomized to treatment, 314 patients (98%) completed the final study assessment. Improvement in the average WOMAC Index pain score was 29.8mm (-61.6%) for Bio-HA and 28.8mm (-54.9%) for CL-HA, meeting the prospective criteria for non-inferiority. For the secondary outcome measures, statistically significant differences favored Bio-HA for the number of patients requiring acetaminophen (P=0.013) and patient global satisfaction evaluations (P=0.03). Local reactions differed between the products in that 15 effusions were reported in 13 CL-HA patients (8.1%) after injection, compared to one effusion (0.6%) after Bio-HA injection (P=0.0015).

CONCLUSION

The effectiveness of Bio-HA was not inferior to that of CL-HA. The significantly higher incidence of post-injection effusion in the CL-HA group provides a safety advantage for Bio-HA. These data suggest that Bio-HA has an improved benefit-risk profile compared with CL-HA.

Assessment of immunologic mechanisms for flare reactions to Synvisc

Intraarticular injection of Synvisc for treatment of knee pain sometimes results in an acute local reaction (flare). We tested the hypothesis that the flare was a Type-1 hypersensitivity reaction as manifested by the presence of Synvisc antibodies in the synovial fluid and serum and by an increase in the concentration of the mast-cell enzyme tryptase in the synovial fluid. Our second objective was to determine whether the ratio of CD4+ to CD8+ lymphocytes in the synovial fluid was increased, as would be expected in a Type-4 hypersensitivity reaction. The study population was a prospective, consecutive series of 16 patients who had a flare, and 20 control patients. We found no differences in product-specific antibodies in the synovial fluid or serum between patients with flares and patients without flares. The mean tryptase level in the synovial fluid of patients with flares, 3.8 +/- 0.8 microg/L, was not different from the corresponding level in the control patients. The CD4+/CD8+ ratio in the synovial fluid was more than eight times greater in patients with flares. Flares that sometimes occur after treatment with Synvisc are probably not Type-1 (antibody-mediated) hypersensitivity reactions, but may be Type-4 (cell-mediated) hypersensitivity reactions.

Nonoperative treatment of unicompartmental arthritis of the knee

Treatment of the knee with unicompartmental osteoarthritis remains a challenging clinical problem. Despite pharmacologic advances and surgical innovations, the ideal strategy for the patient who has single-compartment degenerative disease can be complicated. The understanding and management of this problem are further confounded by the fact that so much of the data are unreliable. Given these constraints, this article outlines the current alternatives available in nonoperatively managing the symptomatic unicompartmental arthritic knee.

Successful nonoperative management of chronic osteoarthritis pain of the knee: safety and efficacy of retreatment with intra-articular hyaluronans

CONTEXT

Although there are many nonsurgical therapies available for the treatment of pain associated with osteoarthritis (OA), their long-term use and safety have not been systematically followed. Intra-articular hyaluronan therapy has been used in the treatment of symptoms associated with OA of the knee with a very favorable safety profile. Five intra-articular hyaluronan products are approved in the US. No systematic review of the safety and efficacy of their chronic use has been reported.

OBJECTIVE

To evaluate the literature on the efficacy and safety of repeat courses of hyaluronan therapy in patients with OA of the knee.

DATA SOURCES

MEDLINE, EMBASE, searched through October 2004.

STUDY SELECTION

Databases were searched using the terms hyaluronan, sodium hyaluronate, hyaluronic acid, hylan, hylan G-F 20, osteoarthritis, adverse events, repeat treatment, and multiple courses.

DATA SYNTHESIS

There are some data that support the benefit and safety of repeat treatment for all products. Data also indicate that one formulation of sodium hyaluronate (molecular weight [MW] 500-730 kDa) is well tolerated and as effective after multiple courses of treatment as it is after a single course. There is also clinical evidence that prolonged use of sodium hyaluronate (MW 500-730 kDa) may significantly decrease the rate of deterioration of joint structure. Localized severe acute inflammatory reactions reported with repeated treatment in some patients are not a class effect but may be linked to physicochemical characteristics of hylan-based treatment.

CONCLUSIONS

Repeat courses of the hyaluronans are safe and effective in the treatment of pain associated with OA of the knee.

Viscosupplementation for the treatment of osteoarthritis of the knee

BACKGROUND

Osteoarthritis (OA) is the most prevalent chronic joint disorder worldwide and is associated with significant pain and disability.

OBJECTIVES

To assess the effects of viscosupplementation in the treatment of OA of the knee. The products were hyaluronan and hylan derivatives (Adant, Arthrum H, Artz (Artzal, Supartz), BioHy (Arthrease), Durolane, Fermathron, Go-On, Hyalgan, Hylan G-F 20 (Synvisc Hylan G-F 20), NRD-101, Orthovisc, Ostenil, Replasyn, SLM-10, Suplasyn, Synject and Zeel compositum).

SEARCH STRATEGY

MEDLINE, EMBASE, PREMEDLINE, Current Contents up to July 2003, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched. Specialised journals and reference lists of identified randomised controlled trials (RCTs) and pertinent review articles up to April 2004 were handsearched.

SELECTION CRITERIA

RCTs of viscosupplementation for the treatment of people with a diagnosis of OA of the knee were eligible. Single and double-blinded studies, placebo-based and comparative studies were eligible. At least one of the four OMERACT III core set outcome measures had to be reported (Bellamy 1997).

DATA COLLECTION AND ANALYSIS

Each trial was assessed independently by two reviewers (NB, JC) for its methodological quality using a validated tool. All data were extracted by one reviewer (JC) and verified by a second reviewer (VR). Continuous outcome measures were analysed as weighted mean differences (WMD) with 95% confidence intervals (CI). Dichotomous outcomes were analyzed by relative risk (RR).

MAIN RESULTS

Sixty-three trials with a median quality score of 3 (range 1 to 5) were identified. Follow-up periods varied between day of last injection and one year. Thirty-seven trials included comparisons of hyaluronan/hylan and placebo, nine trials included comparisons of intra-articular (IA) corticosteroids, and five trials included comparisons of nonsteroidal anti-inflammatory drugs (NSAIDs). The pooled analyses of the effects of viscosupplements against 'placebo' controls generally supported the efficacy of this class of intervention. In these same analyses, differential efficacy effects were observed for different products on different variables and at different timepoints. Of note is the 5 to 13 week post injection period which showed a percent improvement from baseline of 11 to 54% for pain and 9 to 15% for function. In general, comparable efficacy was noted against NSAIDs and longer-term benefits were noted in comparisons against IA corticosteroids. In general, few adverse events were reported in the hyaluronan/hylan trials included in these analyses.

AUTHORS' CONCLUSIONS

Based on the aforementioned analyses, viscosupplementation is an effective treatment for OA of the knee with beneficial effects: on pain, function and patient global assessment; and at different post injection periods but especially at the 5 to 13 week post injection period. It is of note that based on non-randomised groups, the magnitude of the clinical effect, as expressed by the WMD and standardised mean difference (SMD) from the RevMan 4.1 output, is different for different products, comparisons, timepoints, variables and trial designs. However, there are few randomised head-to-head comparisons of different viscosupplements and readers should be cautious, therefore, in drawing conclusions regarding the relative value of different products. The clinical effect for some products, against placebo, on some variables at some timepoints is in the moderate to large effect-size range. Readers should refer to relevant tables to review specific detail given the heterogeneity in effects across the product class and some discrepancies observed between the RevMan 4.1 analyses and the original publications. Overall, the analyses performed are positive for the HA class and particularly positive for some products with respect to certain variables and timepoints, such as pain on weight bearing at 5 to 13 weeks postinjection. In general, sample-size restrictions preclude any definitive comment on the safety of the HA class of products; however, within the constraints of the trial designs employed no major safety issues were detected. In some analyses viscosupplements were comparable in efficacy to systemic forms of active intervention, with more local reactions but fewer systemic adverse events. In other analyses HA products had more prolonged effects than IA corticosteroids. Overall, the aforementioned analyses support the use of the HA class of products in the treatment of knee OA.

Granulomatous synovitis after intraarticular Hylan GF-20. A report of two cases

Intraarticular hyaluronan injections are used to treat osteoarthritis of the knee. Acute painful swelling with a joint effusion develops locally after the injection in about 10% of cases but resolves spontaneously. Crystals are identifiable in some patients, but the mechanism in crystal-negative cases remains unknown. We report knee arthritis with inflammatory joint fluid free of organisms and crystals in two patients after Hylan GF-20 treatment for femorotibial osteoarthritis. Synovial membrane histology disclosed granulomatous synovitis with epithelioid histiocytic and multinucleate giant cells but no visible foreign bodies. These two cases suggest that crystal-negative arthritis after Hylan GF-20 injection may be ascribable to granulomatous synovitis of the foreign-body giant-cell type.

Injections and return to play

The use of analgesic and anti-inflammatory injections in athletics has a long and sometimes controversial history. They have been and will continue to be utilized to decrease inflammation and pain, improve healing time, and ultimately decrease the amount of time missed from sports competition. Several authors have evaluated both the positive and negative aspects of various injectable medicines. Many questions still remain with regard to safety, tolerability, risks, complications, and side effects of these injectable medicines. This paper reviews some of the current trends regarding the use of injectable medications in athletic medicine.

Effectiveness and safety of repeat courses of hylan G-F 20 in patients with knee osteoarthritis

OBJECTIVE

To compare the effectiveness and safety of repeat treatment with hylan G-F 20 based on data from a randomized, controlled trial [Raynauld JP, Torrance GW, Band PA, Goldsmith CH, Tugwell P, Walker V, et al. A prospective, randomized, pragmatic, health outcomes trial evaluating the incorporation of hylan G-F 20 into the treatment paradigm for patients with knee osteoarthritis (Part 1 of 2): clinical results. Osteoarthritis Cartilage 2002;10:506-17]. The hypotheses tested were whether the single-course and repeat-course subgroups would be superior to appropriate care and not different from each other.

METHOD

A total of 255 patients with knee osteoarthritis were randomized to "appropriate care with hylan G-F 20" or "appropriate care without hylan G-F 20". The hylan G-F 20 group was partitioned into two subgroups: (1) patients who received a single course of hylan G-F 20; and (2) patients who received two or more courses of hylan G-F 20.

RESULTS

For the primary effectiveness measure, change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score as a percent of baseline, the single-course subgroup improved by 41%, the repeat-course subgroup by 35%, and the appropriate care group by 14%. Both subgroups improved significantly more than the appropriate care group (P<0.05), and were not statistically significantly different from each other (70% power to detect a 20% difference). Secondary effectiveness measures showed similar results. In the repeat-course subgroup, no statistically significant differences were found in the number of local adverse events, the number of patients with local adverse events, or arthrocentesis rates between the first and repeat courses of treatment.

CONCLUSIONS

Although the study was neither designed nor powered to examine repeat treatment, this a posteriori analysis provides support for a favorable effectiveness and safety profile of hylan G-F 20 in repeat course patients.

Non-Animal Stabilized Hyaluronic Acid

Hyaluronic acid (HA) is a major component of human synovial fluid, providing the rheologic properties (elasticity and viscosity) that enable the synovial fluid to perform lubricating and shock-absorbing functions within the healthy joint. Over the last 2 decades, HA preparations have become established in intra-articular therapy of osteoarthritis (OA), particularly OA of the knee. Existing HA preparations, both cross-linked and non-cross-linked, are all administered by courses of multiple injections, and all have been associated with variable success rates. The clinical profile of an HA preparation is inextricably linked to the product's physicochemical properties. For example, the molecular structure of the HA affects the intra-articular residence time, which should in turn influence the duration of action post-injection. Non-animal stabilized hyaluronic acid (NASHA) is a new-generation HA preparation, produced wholly from non-animal sources. NASHA is stabilized using a carefully controlled cross-linking process, which increases the intra-articular residence time from hours to weeks. This facilitates single-injection treatment for OA without affecting the biocompatibility of HA. This review evaluates the properties of NASHA, including the available clinical data, in the context of previously developed HA preparations.

Efficacy and safety of a single intra-articular injection of non-animal stabilized hyaluronic acid (NASHA) in patients with osteoarthritis of the knee

OBJECTIVE

Non-animal stabilized hyaluronic acid (NASHA) is a novel hyaluronan (HA) preparation with a 4-week intra-articular half-life. This study compared the efficacy of a single injection of NASHA with placebo in patients with osteoarthritis (OA) of the knee.

DESIGN

This was a 26-week randomized, double-blind, multicenter study of a single intra-articular knee injection with either NASHA or placebo (saline). Assessments included the Western Ontario McMasters Universities osteoarthritis index (WOMAC, Likert Scale) and patients' overall global disease status. A positive response was defined as a reduction in WOMAC pain score for the study knee of 40% from baseline with a minimum improvement of > or =5 points.

RESULTS

A total of 346 (NASHA 172; placebo 174) patients were treated. WOMAC scores and quality of life were improved in both the NASHA and placebo groups. For the overall population, there were no statistically significant between-group differences in response rates for any efficacy parameters. In patients with OA confined to the knee (N=216), a greater response to NASHA than placebo was observed at week 6 (P=0.025). There were few treatment-related events.

CONCLUSIONS

NASHA was not superior to placebo for the primary efficacy analysis. However, these data may be confounded by the inclusion of patients with OA at other sites, as significant benefits over placebo were found among patients with OA confined to the knee. Future trials of OA that examine a local therapy might need to consider restricting the study population to those patients having OA of only the signal joint.

Acute pseudoseptic arthritis after intraarticular sodium hyaluronan

A 70-year-old woman with a history of knee osteoarthritis was admitted for acute arthritis 9 days after a second intraarticular injection of sodium hyaluronan (Ostenil). The joint fluid was purulent, with no crystals, and laboratory tests showed marked inflammation, leading to antibiotic treatment for suspected septic arthritis. Incapacitating symptoms persisted, prompting surgical lavage of the knee, which failed to relieve the severe pain. The persistent symptoms and negative results of joint fluid and blood cultures led to discontinuation of the antibiotic therapy after 10 days. Antiinflammatory therapy relieved the symptoms, and the patient was discharged home 1 month after her admission. Nevertheless, the pain persisted, requiring rehabilitation therapy of the knee. Aseptic arthritis induced by repeated sodium hyaluronan injection is the most likely diagnosis. Physicians should be aware of this extremely severe complication.

Therapeutic effects of hyaluronic acid on osteoarthritis of the knee. A meta-analysis of randomized controlled trials

BACKGROUND

The magnitude of the therapeutic effects of intra-articular injection of hyaluronic acid on osteoarthritis of the knee is still in question. The aim of this meta-analysis was to elucidate the therapeutic efficacy and safety of intra-articular injection of hyaluronic acid for osteoarthritis of the knee.

METHODS

We conducted a meta-analysis of twenty blinded randomized controlled trials that compared the therapeutic effect of intra-articular injection of hyaluronic acid with that of intra-articular injection of a placebo to treat osteoarthritis of the knee. The outcome end points were classified into three categories: pain with activities, pain without activities, and function. The outcome measures of the efficacy of hyaluronic acid were the mean differences in the efficacy scores between the hyaluronic acid and placebo groups. The outcome measure of the safety of hyaluronic acid was the relative risk of adverse events.

RESULTS

Intra-articular injection of hyaluronic acid can decrease symptoms of osteoarthritis of the knee. We found significant improvements in pain and functional outcomes with few adverse events. However, there was significant between-study heterogeneity in the estimates of the efficacy of hyaluronic acid. Subgroup analysis and meta-regression analysis showed that lower methodological quality such as a single-blind or single-center design resulted in higher estimates of hyaluronic acid efficacy, that introduction of acetaminophen as an escape analgesic in the trial resulted in lower estimates of hyaluronic acid efficacy, and that patients older than sixty-five years of age and those with the most advanced radiographic stage of osteoarthritis (complete loss of the joint space) were less likely to benefit from intra-articular injection of hyaluronic acid.

CONCLUSIONS

This meta-analysis confirmed the therapeutic efficacy and safety of intra-articular injection of hyaluronic acid for the treatment of osteoarthritis of the knee. Additional well-designed randomized controlled trials with high methodological quality are needed to resolve the continued uncertainty about the therapeutic effects of different types of hyaluronic acid products on osteoarthritis of the knee in various clinical situations and patient populations.

LEVEL OF EVIDENCE

Therapeutic study, Level II-3b (systematic review; nonhomogeneous Level-I studies). See Instructions to Authors for a complete description of levels of evidence.

Medical management of osteoarthritis of the knee and hip joints

Osteoarthritis is a common, chronic condition which requires an individualised management plan involving multiple kinds of treatment. Exercise programs and the Arthritis Self-Management Program reduce pain and disability associated with osteoarthritis. Paracetamol is the most appropriate first-line analgesic. Non-steroidal anti-inflammatory drugs may be used as second-line analgesia on an as-needed basis (including continuous use), but must be used with caution. Cyclo-oxygenase-2-specific inhibitors are used if there are risk factors for upper-gastrointestinal complications, but only after considering cardiovascular risk. Glucosamine sulfate is a safe and effective over-the-counter treatment. Intra-articular therapies are used when others have failed.

Pseudoseptic reactions to hylan viscosupplementation: diagnosis and treatment

Hyaluronans are used widely in the treatment of osteoarthritis of the knee. Three commercial hyaluronan preparations currently are available in the United States: sodium hyaluronate (Hyalgan), sodium hyaluronate (Supartz), and hylan G-F 20 (Synvisc). Although the sodium hyaluronates are derived naturally, hylan is chemically modified to increase its molecular weight. All three products have been shown to be well tolerated in clinical trials, however, there have been reports in the literature of pseudoseptic reactions, or severe acute inflammatory reactions, after injections with hylan. Our study reviewed the reported incidence of pseudosepsis. The pathogenic mechanisms and clinical treatment of this reaction are presented.

The tolerability of viscosupplementation: low incidence and clinical management of local adverse events

Hylan G-F 20 (Synvisc, Genzyme Biosurgery, Ridgefield, NJ) is a visco supplement indicated for the treatment of pain due to osteoarthritis (OA) of the knee. Overall, the therapy is well tolerated with a low incidence of local and systemic adverse events (AEs). In our large clinical practice, our overall rate of local pain and swelling with treatment is consistent with that of previous reports and the product labeling. Local AEs that do occur with therapy are mostly mild to moderate in nature, transient, and resolve spontaneously or with symptomatic treatment. Local AEs thought to be related to the treatment are clinically manageable and do not result in long-term sequelae, such that their occurrence should not preclude patients from the benefit of OA pain relief with therapy, including continued pain relief with repeat treatment. Based on previous published reports of hylan G-F 20 and our extensive clinical experience, relief of OA knee pain with hylan G-F 20 far outweighs the low risk of local AEs for patients who do not respond to other therapies indicated for the treatment of OA knee pain.