Efficacy of 3 Weekly Injections of Hyaluronate in Patients With Ankle Osteoarthritis

Viscosupplementation with 3 to 5 weekly hyaluronate injections is a well-established treatment option in knee osteoarthritis. Previous studies reported that five weekly hyaluronate injections were safe and effective for the treatment of ankle osteoarthritis. However, the effect of three weekly injections has rarely been investigated. Besides, no study to date has assessed whether balance function would change after HA injections in patients with ankle OA. The purpose of this study was to evaluate the efficacy and safety of three weekly injections of sodium hyaluronate (Hyalgan) in patients with unilateral ankle osteoarthritis. Pain, physical function and balance will be assessed as parameters for the effectiveness.

Inclusion criteria

• were 18 years of age or older, reported unilateral ankle pain for at least 6 months and had either reported no significant benefit from conservative treatment (rest, physical therapy, orthoses or pain medications etc.) or were unable to tolerate side effects of medications
• ankle radiographs taken within 6 months were equivalent to grade 2 or 3 according to the Kellgren-Lawrence grading system (grade 2, definite osteophytes and possible narrowing of joint space; grade 3, moderate multiple osteophytes, definite narrowing of joint space, some sclerosis and possible deformity of bone contour)22
• had a current total AOS score (described below) of > 3 and < 9 (possible range, 0-10)
• were normally active, not bedridden or confined to a wheelchair, and were able to walk 30 meters without the aid of a walker, crutches or cane
• were willing to discontinue all nonsteroidal anti-inflammatory drugs (NSAIDs) or other analgesic medication (except for rescue medication) for the duration of the study
• did not receive physical therapy or trial of shoe modifications or orthotics during the study period

Exclusion criteria

• pregnant and lactating women
• bilateral ankle OA requiring treatment of both ankles
• chronic ankle instability
• lower leg trauma other than within the ankle
• previous orthopedic surgery on the spine, hip or knee
• presence of active joint infections of foot or ankle
• previous surgery or arthroscopy on the ankle within 12 months
• intraarticular steroid or HA injection in the treated ankle within the past 6 months
• treatment with anticoagulants or immunosuppressives
• history of rheumatoid arthritis, gout, or any other inflammatory arthropathy
• history of avian protein allergy
• presence of other comorbidity (neoplasm, diabetes mellitus, paresis, recent trauma, etc) or poor health status that would interfere with the clinical assessments during the study