Background: Acute lateral ankle sprains are common musculoskeletal injuries presenting to emergency departments. Optimal conservative management remains debated. Immobilization and functional treatment using ankle braces are widely used, each with distinct advantages. To compare clinical and functional outcomes of below-knee slab immobilization versus flexible ankle brace treatment in acute lateral ankle sprain.

Methods: This was a prospective comparative quasi-experimental study conducted at Kathmandu Medical College Teaching Hospital from May 2023 to May 2024. Sixty patients aged 18–50 years presenting within 72 hours of a Grade II or III lateral ankle sprain were alternately assigned to two groups. Group A received a flexible ankle brace while Group B received below-knee slab immobilization. Outcomes were assessed using the Karlsson score at days 10 and 30, ankle-girth difference at day 30, and VAS pain scores at day 10. Data were analyzed with SPSS 20 and p < 0.05 was significant.

Results: At day 10, mean Karlsson scores were comparable between the brace (48.7 ± 8.50) and slab (50.2 ±8.14) groups (p > 0.05). By day 30, the brace group showed higher scores (78.4 ± 1.73 vs. 66 ±1.98, p < 0.05). Swelling at day 30 was lower in the brace group (0.66 ± 1.72 cm vs. 1.8 ±2.45 cm, p < 0.05). VAS pain scores at day 10 showed no significant difference (p > 0.05).

Conclusion: Functional treatment with a flexible ankle brace provides faster recovery, greater functional improvement, and reduced swelling compared to below-knee slab immobilization. Functional bracing should be preferred in suitable cases.

Keywords: Ankle Injuries, Braces, Immobilization, Splints, Sprains and Strains