Hyaluronic acid and other conservative treatment options for osteoarthritis of the ankle

Background The cause of ankle osteoarthritis (OA) is usually trauma. Patients are relatively young, since ankle trauma occurs at a relatively young age. Several conservative treatment options are available, evidence of the benefits and harms of these options are lacking. Objectives To assess the benefits and harms of any conservative treatment for ankle OA in adults in order to provide a synthesis of the evidence as a base for future treatment guidelines. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2014, issue 9), MEDLINE (Ovid) (1946 up to 11 September 2014), EMBASE (1947 to September 2014), PsycINFO (1806 to September 2014), CINAHL (1985 to September 2014), PEDro (all years till September 2014), AMED until September 2014, ClinicalTrials.gov, Current Controlled Trials, The Dutch Register. To identify potentially relevant studies we screened reference lists in retrieved review articles and trials. Selection criteria We considered randomised or controlled clinical trials investigating any non‐surgical intervention for ankle OA for inclusion. Data collection and analysis We used standard methodological procedures expected by Cochrane. Main results No other RCT concerning any other conservative treatment besides the use of hyaluronic acid (HA) for ankle OA was identified. Six randomised controlled trials (RCTs) were included. A total of 240 participants diagnosed with ankle OA were included in this review. The primary analysis included three RCTs (109 participants) which compared HA to placebo. One study compared HA to exercise therapy, one compared HA combined with exercise therapy to an intra‐articular injection of botulinum toxin and one compared four different dosages of HA. Primary analysis: a pooled analysis of two trials (45 participants) found that the Ankle Osteoarthritis Scale (AOS) total score (measuring pain and physical function) was reduced by 12% (95% CI −24% to −1%) at six months (mean difference (MD) −12.53 (95% CI −23.84 to −1.22) on a scale of 0 to 100; number needed to treat for an additional beneficial outcome (NNTB) = 4 (95% CI 2 to 205); this evidence was graded as low quality, due to limitations in study design (unclear risk of selection bias for two studies and unclear risk for attrition bias for one study) and imprecision of results: a small population size (45 participants). It is not known if a mean difference of 12.53 points on a 100 point scale is clinically relevant. No minimal importan