Intra-articular hyaluronic acid in the treatment of osteoarthritis of the knee: clinical and morphological study.
OBJECTIVE
To evaluate, in a pilot, open clinical trial on 40 patients with knee osteoarthritis, the structural changes in the synovial membrane and cartilage following treatment with intra-articular hyaluronic acid (HA-Hyalgan).


METHODS
The structural effects of HA given as 5 weekly injections (20 mg/2 ml once a week for 5 weeks), were evaluated by microarthroscopy and morphological analysis of biopsy samples taken at baseline and after 6 months, under blind conditions. Clinical efficacy was also evaluated using visual analogue scales for pain and functional parameters.


RESULTS
At 6 months, the microarthroscopic evaluation indicated that the majority of the patients (60%) showed no changes compared to baseline, while 32.5% of the patients showed improvement in the grading and/or extension of cartilage lesions and 7.5% showed a worsened condition. These changes were accompanied by a statistically significant reduction in the synovial inflammation (p = 0.001). The results were confirmed by morphological examination of the cartilage and synovial membrane. At 6 months compared to baseline, a statistically significant reconstitution of the superficial amorphous layer of the cartilage (p = 0.0039), an improvement in the chondrocyte density (p = 0.0023) and vitality (p = 0.05), and a statistically significant reduction in synovial inflammation (p = 0.0001) accompanied by a significant increase in the synovial repair process (p = 0.0001) were observed. Significant and long lasting improvement in pain and joint mobility were also seen after HA treatment. Joint effusion, when present, was reduced. The treatment was well tolerated.


CONCLUSIONS
Hyalgan represents a useful therapy for knee OA, with long-lasting symptomatic efficacy and potential positive effects on joint tissues. Other studies, in particular placebo-controlled studies, are warranted to confirm these promising results observed on joint tissues.
Frizziero
L
L
Department of Internal Medicine, Maggiore Hospital, Bologna, Italy.
Govoni
E
E
Bacchini
P
P
D000328:Adult; D001182:Arthroscopy; D002358:Cartilage, Articular / Q000187:drug effects / Q000473:pathology; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000627:therapeutic use*; D007270:Injections, Intra-Articular; D007719:Knee Joint / Q000187:drug effects* / Q000473:pathology; D008297:Male; D008866:Microsurgery; D008875:Middle Aged; D010003:Osteoarthritis / Q000188:drug therapy* / Q000473:pathology; D010146:Pain / Q000188:drug therapy / Q000503:physiopathology; D010865:Pilot Projects; D016059:Range of Motion, Articular / Q000187:drug effects; D013583:Synovial Membrane / Q000187:drug effects / Q000473:pathology; D016896:Treatment Outcome; D016474:Weight-Bearing / Q000502:physiology
D006820:Hyaluronic Acid