Patients with knee osteoarthritis (OA) who can best benefit from treatment with intra-articular hyaluronic acid injections include patients with high levels of knee pain, younger individuals, persons with a high body mass index (BMI), and individuals with less severe structural damage, according to the results of a 9-year, prospective, longitudinal follow-up study published in Arthritis Research & Therapy.

The investigators sought to identify determinants associated with an improved response to intra-articular hyaluronic acid treatment in individuals with knee OA, since current guidelines are not unanimous with respect to the utility of this treatment and the current literature provides inconsistent results. In the present study, participants were selected from the Osteoarthritis Initiative database. All participants had radiographic evidence of OA, had received 1 intra-articular hyaluronic acid treatment, and had data available on demographic and Western Ontario and McMaster University Osteoarthritis Index (WOMAC) scores before and within 6 months following treatment.

Pain was assessed before treatment within 6 months following treatment. Participants with WOMAC pain scores >0 before treatment were subdivided into low, moderate, and high pain groups. Additional analysis was conducted in the high pain group (score ≥8), which was further divided into responders (improvement in pain score of ≥20%) and nonresponders (unchanged or worsening pain).

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A total of 310 participants received 404 treatments (1 per knee). In the low and moderate pain groups, participants had significantly lower scores before treatment compared with the high pain group (P <.001). Moreover, the low vs high pain group had significantly lower BMI (P =.002), greater joint space width (P =.010) and knee cartilage volume (P ≤.009), and smaller synovial effusion (P =.033).

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Responders vs nonresponders in the high pain group were typically younger (P =.014), had greater cartilage volume in the medial compartment (P =.046), demonstrated a trend toward greater joint space width, and reported a significant improvement in all WOMAC scores (P <.001). Nonresponders, on the other hand, exhibited worsening of symptoms.

The investigators concluded that the study provided reliable predictive determinants for identifying individuals with knee OA who can best benefit from intra-articular hyaluronic acid injection therapy. Implementation of these findings into clinical practice can serve as a useful guide for physicians. Longer-term, controlled studies, along with safety assessments, are warranted, in order to further elucidate these initial findings.


Pelletier JP, Raynauld JP, Abram F, Dorais M, Delorme P, Martel-Pelletier J. Exploring determinants predicting response to intra-articular hyaluronic acid treatment in symptomatic knee osteoarthritis: 9-year follow-up data from the Osteoarthritis Initiative. Arthritis Res Ther. 2018;20(1):40.