A risk-benefit assessment of injections of hyaluronan and its derivatives in the treatment of osteoarthritis of the knee

Corticosteroid compared with hyaluronic acid injections for the treatment of osteoarthritis of the knee. A prospective, randomized trial

BACKGROUND

Although both corticosteroid and hyaluronic acid injections are widely used to palliate the symptoms of knee osteoarthritis, little research involving a comparison of the two interventions has been done. We tested the hypothesis that there are no significant differences between Hylan G-F 20 (Synvisc) and the corticosteroid betamethasone sodium phosphate-betamethasone acetate (Celestone Soluspan) in terms of pain relief or improvement in function, as determined by validated scoring instruments.

METHODS

One hundred patients with knee osteoarthritis were randomized to receive intra-articular injection of either Hylan G-F 20 or the corticosteroid, and they were followed for six months. The patients treated with Hylan G-F 20 received one course of three weekly injections. The patients treated with the corticosteroid received one injection at the time of enrollment in the study, and they could request one more injection any time during the study. An independent, blinded evaluator assessed the patients with the Western Ontario and McMaster University Osteoarthritis Index (WOMAC), a modification of the Knee Society rating system, and the visual analog pain scale.

RESULTS

Both the group treated with the corticosteroid and the group treated with Hylan G-F 20 demonstrated improvements from baseline WOMAC scores (a median decrease from 55 to 40 points and from 54 to 44 points, respectively; p < 0.01 for both). The scores according to the Knee Society system did not significantly improve for the patients who received the corticosteroid (median, 58 to 70 points; p = 0.06) or for those who received Hylan G-F 20 (median, 58 to 68 points; p = 0.15). The scores on the visual analog scale improved for patients receiving Hylan G-F 20 (median, 70 to 52 mm; p < 0.01) but not for the patients who received the corticosteroid (median, 64 to 52 mm; p = 0.28). However, no significant differences between the two treatment groups were found with respect to the WOMAC, Knee Society system, or visual analog scale results. Women demonstrated a significant improvement in only one of the six possible outcome-treatment combinations (the WOMAC scale), whereas men demonstrated significant improvements in five of the six outcomes (all measures except the Knee Society rating system).

CONCLUSIONS

No differences were detected between patients treated with intra-articular injections of Hylan G-F 20 and those treated with the corticosteroid with respect to pain relief or function at six months of follow-up. Women demonstrated significantly less response to treatment than men did for both treatments on all three outcome scales. Such significant gender-related differences warrant further investigation.

Intra-articular hyaluronan therapy

Viscosupplementation, in which hyaluronan derivatives are injected into the intra-articular space of osteoarthritic joints, is now widely used to treat knee osteoarthritis (OA). No viscosupplements have been approved for osteoarthritic joints other than the knee. To date, no clinical trials using viscosupplements to treat ankle or foot OA have been published. However, the mechanisms thought to be responsible for viscosupplementation's therapeutic effects would likely apply in any synovial joint. A goal of this article is to stimulate interest in research to assess the potential role of viscosupplementation in treating foot and ankle OA.

Hylan G-F 20 induces delayed foreign body inflammation in Guinea pigs and rabbits

Recent clinical evidence suggests that hylan, a modified hyaluronan, and related products potentially elicit foreign body granulomatous inflammation in human soft tissue. We investigated the biocompatibility of hylan G-F 20 (Synvisc) for up to 28 days after intradermal injection in guinea pigs and intramuscular injection in rabbits. Compared to saline and unmodified hyaluronan, hylan induced definitive macroscopic changes in guinea pigs by day 14 or later and in rabbits by 28 days after injection. Histologically, at the injection sites, there was severe granulomatous inflammation in guinea pigs and acute inflammation with minimal infiltration of macrophages and foreign body giant cells in rabbits. Furthermore, specific antibodies against hylan were demonstrated in guinea pigs by passive cutaneous anaphylaxis, and substantial deposits of IgG on hylan were evident by immunohistochemistry. The present results contradict previous reports on biocompatibility of hylan and suggest that hylan may potentially induce similar unfavorable reactions in humans.

Intra-articular hyaluronans: a review of product-specific safety profiles

BACKGROUND AND OBJECTIVES

Intra-articular (IA) hyaluronans (HAs) are indicated for pain relief of osteoarthritis (OA) of the knee. Hyalgan (sodium hyaluronate), Supartz (sodium hyaluronate), and Synvisc (hylan G-F 20) are Food and Drug Administration-approved HA products. They are derived from rooster combs; Hyalgan and Supartz are naturally derived (unmodified); Synvisc is chemically modified to increase its molecular weight. This article reviews and updates the safety data for IA HAs used for the treatment of knee OA.

METHODS

References were taken from Medline through July 2002; respective product information services and information from the searchable United States Food and Drug Administration Manufacturer and User Facility Device Experience Database also were used.

RESULTS

All products demonstrated favorable safety profiles in clinical trials and practice compared to other standard therapies for management of OA knee pain. The most common adverse event associated with HAs is mild injection site pain and swelling. Each product has had rare reports of pseudogout and anaphylactoid reactions. Product-specific adverse events, severe acute inflammatory reactions (pseudoseptic knee), in patients receiving Synvisc have been reported. One such patient developed antibodies to chicken proteins and hylan, suggesting an immunologic basis for the severe acute inflammatory reaction. Data from an animal study support a possible immunogenic difference between Synvisc and Hyalgan.

CONCLUSIONS AND RELEVANCE

Overall, HA therapy is a safe treatment for OA knee pain, although there may be interproduct variability in safety profiles.

Diphenhydramine and hyaluronic acid derivatives reduce adnexal adhesions and prevent tubal obstructions in rats

OBJECTIVE

The purpose of this study is to investigate the effects of diphenhydramine-HCl and Na-hyaluronate derivatives on the development of postoperative peritoneal adhesion and tubal obstruction.

STUDY DESIGN

Forty female rats of Sprague-Dawley type were used in the study. The rats were divided into four groups, each comprising 10 subjects. After all the rats were anaesthetized with 50mg/kg ketamine HCl, their abdomens were opened with a lower midline incision. Injury was induced on the right pelvic peritoneum and on the peritoneal surface of left uterine tube. No additional procedure was applied to the first group. 10 mg/kg diphenhydramine-HCl was given to the second group intravenously. In the third group, 0.25 mg/kg Orthovisc, a Na-hyaluronate derivative was diluted with 2 ml physiological saline and poured into the abdomen. For the fourth group, Seprafilm, a Na-hyaluronate derivative was covered in a layer of 0.7 cm x 3 cm over the left uterine tube. After 14 days, the rats were anaesthetized with ketamine HCl again, and 5 cm(3) blood sample was taken with cardiac puncture. The abdomen was opened with an incision transverse to the upper end of the midline incision, and the presence of adhesions was investigated. Detected adhesions were staged according to the Mazuji classification. Tubal patencies were inspected by injecting methylene blue from the uterine corpus into the lumen using an injector. A piece of abdominal wall of 4 cm x 4 cm was removed by extending the incision in the reverse U shape. The tensile strength and bursting pressure of the suture line were determined using the Peacock method. One gram of tissue was taken from the incision line, and hydroxyproline levels were determined by the Bergman-Loxley method. Aspartate aminotransferase (AST) levels were measured.

RESULTS

All of the rats completed the study. AST levels, tissue hydroxyproline levels and tensile strength and bursting pressure test results were found to be similar in all groups. While adhesion rates in the groups were 100, 40, 40 and 30%, respectively, adhesion stages were found to be, respectively as 2.1+/-1.7, 0.6+/-0.67, 0.6+/-0.67 and 0.5+/-0.85. Adhesion stages in the study groups were significantly lower (P<0.05). Tubal obstruction rates were found to be 70, 30, 30 and 20%, respectively.

CONCLUSION

Diphenhydramine, Orthovisc and Seprafilm significantly reduce postoperative peritoneal adhesion development, and they allow the uterine tubes to remain open.

Hyaluronic acid hydrogel in the treatment of osteoarthritis

In order to overcome the problem of rapid clearance of the polysaccharide hyaluronic acid (Hyal) in the treatment of osteoarthritis (OA), a 50% cross-linked Hyal hydrogel (Hyal 50%) was synthesised. The 50% refers to the amount of COOH groups of the polysaccharide involved in the cross-linking reaction. i.e. 50% of the total amount. The rheological behaviour of the Hyal 50% hydrogel, and in particular the possibility to inject it through a needle, was studied. The results obtained demonstrated that the hydrogel injected through the needle still behaved like a gel, although it showed a reduction of the dynamic moduli. The most appropriate sterilisation technique for this kind of hydrogel was also evaluated. Liophilised Hyal 50% samples were sterilised by steam, Ethylene Oxide (EtO) and gamma-rays. EtO and gamma-rays did not modify the characteristics of the hydrogel in terms of swellability and morphology. Lastly, the in vivo effect of Hyal 50% hydrogel in the treatment of chondral defect in rabbit knee was also studied. The results obtained showed the Hyal 50% injections improved chondrocytes density and matrix appearance. Furthermore, the permanence in situ of the hydrogel was longer than that of the linear Hyal.

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

BACKGROUND

Intra-articular knee injections with hylan GF-20 (Synvisc) have been shown to provide temporary relief of osteoarthritic symptoms. Several studies have suggested that repeated courses of treatment with this product may be administered without an increase in the likelihood of an adverse reaction. The present study was performed to test the hypothesis that the likelihood of a painful reaction to hylan GF-20 does not increase in patients who receive more than one course of treatment.

METHODS

The records of all patients who had received more than one course of treatment with hylan GF-20 were compared with a group of patients who had received only one course of treatment during the same fifteen-month period at a single center. The single-course group was prospectively enrolled and followed, as part of an ongoing randomized trial. The two groups were compared with respect to several demographic and clinical parameters as well as with respect to the frequency of painful acute local reactions following injections of hylan GF-20.

RESULTS

Local reactions to hylan GF-20 occurred significantly more often in patients who had received more than one course of treatment than they did in patients who had received only a single course of treatment; the reactions occurred in four (21%) of nineteen patients in the former group and in one (2%) of the forty-two patients in the latter (p = 0.029). All of the reactions were severe enough to cause the patient to seek unscheduled care. Following corticosteroid injection, the reactions abated without apparent sequelae. With the numbers available, no significant differences were detected between the multiple-course and single-course groups in terms of age, gender, body-mass index, or severity or bilaterality of the disease.

CONCLUSIONS

The present study suggests that it may be reasonable to counsel patients who have been treated with a course of hylan GF-20 and who desire an additional course that the likelihood of a painful acute local reaction to the medication appears to be increased. Additional study of the frequency of acute local reactions following repeated courses of hylan GF-20 and investigation of the mechanisms of those reactions are warranted.

Synvisc perisynovitis

Synvisc (hylan G-F 20) is a high molecular weight hyaluronan which is manufactured from chicken combs. It is currently one of the options used in the treatment of severe osteoarthritis of the knee joint. Synvisc is directly injected into the diseased joint, where it provides elasticity and viscosity. Published experience suggests than Synvisc is a safe and well-tolerated material with occasional mild local reactions but no long-term adverse sequelae. This article describes a case of Synvisc-related granulomatous inflammation in the perisynovial adipose tissue. To our knowledge, this is the first histological account of tissue reaction to Synvisc.