Hybrid hyaluronic acid versus high molecular weight hyaluronic acid for the treatment of osteoarthritis in obese patients

Obesity is suggested to be a major risk factor for the development of osteoarthritis (OA). The literature reported the intraarticular hyaluronic acid (HA) viscosupplementation was preferred therapy for OA. In this study, Papalia R et al. compared the intraarticular injections of hybrid (low and high molecular weight) hyaluronic acid and revealed better results from hybrid HA than high molecular weight HA in obese patients. 

Knee Osteoarthritis (OA) is one of the most relevant and debilitating health problems. Obesity represents one of the major risk factor for the early development of OA. Knee replacement in obese population should be delayed and eventually avoided. Conservative treatments comprising intraarticular hyaluronic acid (HA) viscosupplementation should be prefered. 

In the present clinical randomized trial, a comparison between two groups of 24 obese patients were presented, randomized to be treated with two intraarticular injections of hybrid (low and high molecular weight) hyaluronic acid (Group A) or two injections of high molecular weight hyaluronic acid (Group B). Patients were followed-up through to 6 months and evaluated though IKDC and KOOS scores, the pain was examined with VAS. 

All patients reported significant improvement when compared to baseline value in all the outcome measures. At 3-month follow-up, IKDC had significantly improved in patients of Group A, compared to Group B (53.1±1.9 vs 51.4±2.4, p=0.0079) and the same for KOOS (52.1±2.0 vs 50.1±2.9, p=0.010). Also, the difference in KOOS was persistently significant at 6-month follow-up (54.7±2.3 vs 51.7±4.9, p=0.014). The VAS reduced significantly more in Group A at 3 months (3.7±0.5 vs 5.2±0.7, p less than 0.001). In an obese population, where basal inflammatory pattern increases the symptoms of OA, and conservative treatment is recommended, HA viscosupplementation improved function and pain of the knee. The treatment with hybrid HA depicted better outcomes than high molecular weight HA in obese patients. 

Combination of the anti-inflammatory action of low molecular weight HA on chondrocytes and the biomechanical role of high molecular weight HA might justify the different results.