BACKGROUND: Osteoarthritis (OA) affecting the first metatarsophalangeal joint (hallux rigidus) is common and painful. Several non-surgical treatments have been proposed; however, few have been adequately evaluated. Since the original 2010 review, several studies have been published necessitating this update. OBJECTIVES: To determine the benefits and harms of non-surgical treatments for big toe OA. SEARCH METHODS: We used standard, extensive Cochrane search methods. The latest search was February 2023. SELECTION CRITERIA: We included randomised trials that compared any type of non-surgical treatment versus placebo (or sham), no treatment (such as wait-and-see) or other treatment. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. The major outcomes were pain, function, quality of life, radiographic joint structure, adverse events and withdrawals due to adverse events. The primary time point was 12 weeks. We used GRADE to assess the certainty of evidence. MAIN RESULTS: This update includes six trials (547 participants). The mean age of participants ranged from 32 to 62 years. Trial durations ranged from 4 to 52 weeks. Treatments were compared in single trials as follows: arch-contouring foot orthoses versus sham inserts; shoe-stiffening inserts versus sham inserts; intra-articular injection of hyaluronic acid versus saline (placebo) injection; arch-contouring foot orthoses versus rocker-sole footwear; peloid therapy versus paraffin therapy; and sesamoid mobilisation, flexor hallucis longus strengthening and gait training plus physical therapy versus physical therapy alone. Certainty of the evidence was limited by the risk of bias and imprecision. Meta-analysis was not performed due to the heterogeneity of interventions. We reported numerical data for the 12-week time point for the three trials that used a placebo/sham control group. Arch-contouring foot orthoses versus sham inserts One trial (88 participants) showed that arch-contouring foot orthoses probably lead to little or no difference in pain, function, or quality of life compared to sham inserts (moderate certainty). Mean pain (0-10 scale, 0 no pain) with sham inserts was 3.9 points compared to 3.5 points with arch-contouring foot orthoses; a difference of 0.4 points better (95% (CI) 0.5 worse to 1.3 better). Mean function (0-100 scale, 100 best function) with sham inserts was 73.3 points compared to 65.5 points with arch-contouring foot orthoses; a difference of 7.8 points worse (95% CI 17.8 worse to 2.2 better). Mean quality of life (-0.04-100 scale, 100 best score) with sham inserts was 0.8 points compared to 0.8 points with arch-contouring foot orthoses group (95% CI 0.1 worse to 0.1 better). Arch-contouring foot orthoses may show little or no difference in adverse events and withdrawal due to adverse events compared to sham inserts (low certainty). Adverse events (mostly foot pain) were reported in 6 out of 41 people with sham inserts and 4 out of 47 people with arch-contouring foot orthoses (RR 0.58, 95% CI 0.18 to 1.92). Withdrawals due to adverse events were reported in 0 out of 41 people with sham inserts and 1 out of 47 people with arch-contouring foot orthoses (Peto OR 6.58, 95% CI 0.13 to 331). Shoe-stiffening inserts versus sham inserts One trial (100 participants) showed that shoe-stiffening inserts probably lead to little or no difference in pain, function, or quality of life when compared to sham inserts (moderate certainty). Mean pain (0-100 scale, 0 no pain) with sham inserts was 63.8 points compared to 70.1 points with shoe-stiffening inserts; a difference of 6.3 points better (95% CI 0.5 worse to 13.1 better). Mean function (0-100 scale, 100 best function) with sham inserts was 81.0 points compared to 84.9 points with shoe-stiffening inserts; a difference of 3.9 points better (95% CI 3.3 worse to 11.1 better). Mean quality of life (0-100 scale, 100 best score) with sham inserts was 53.2 points compared to 53.3 points with shoe-stiffening inserts; a difference of 0.1 points better (95% CI 3.7 worse to 3.9 better). Shoe-stiffening inserts probably show little or no difference in adverse events (moderate-certainty) and may show little or no difference in withdrawal due to adverse events (low-certainty), compared to sham inserts. Adverse events (mostly foot pain, blisters, and spine/hip pain) were reported in 31 out of 51 people with sham inserts and 29 out of 49 people with shoe-stiffening inserts (RR 0.94, 95% CI 0.42 to 2.08). Withdrawals due to adverse events were reported in 1 out of 51 people with sham inserts and 2 out of 49 people with shoe-stiffening inserts (Peto OR 2.08, 95% CI 0.19 to 22.23). Hyaluronic acid versus placebo One trial (151 participants) showed that a single intra-articular injection of hyaluronic acid probably leads to little or no difference in pain or function compared to placebo (moderate certainty). Mean pain (0-100 scale, 0 no pain) with placebo was 72.5 points compared to 68.2 points with hyaluronic acid; a difference of 4.3 points better (95% CI 2.1 worse to 10.7 better). Mean function (0-100 scale, 100 best function) was 83.4 points with placebo compared to 85.0 points with hyaluronic acid; a difference of 1.6 points better (95% CI 4.6 worse to 7.8 better). Hyaluronic acid may provide little or no difference in quality of life (0-100 scale, 100 best score) which was 79.9 points with placebo compared to 82.9 points with hyaluronic acid; a difference of 3.0 better (95% CI 1.4 worse to 7.4 better; low certainty). There may be fewer adverse events with hyaluronic acid compared to placebo. Adverse events (mostly pain at the injection site) were reported in 43 out of 76 people with placebo compared with 27 out of 75 people with hyaluronic acid (RR 0.64, 95% CI 0.44 to 0.91; low certainty). No participants withdrew from either group due to adverse events. The effects on radiographic joint structure were not reported in any study. AUTHORS' CONCLUSIONS: The existing evidence regarding the benefits and harms of non-surgical treatments for big toe OA is limited. There is moderate-certainty evidence, based upon three single placebo/sham-controlled trials, that there are no clinically important benefits of arch-contouring foot orthoses, shoe-stiffening inserts, or a single intra-articular injection of hyaluronic acid. Further placebo-controlled trials are needed to evaluate the effectiveness of non-surgical treatments for big toe OA.