Junyu Bai, Jinqiao Zhang
Rotator cuff injury (RCI) is a common age-related musculoskeletal disorder, yet public awareness remains limited. With short-video platforms emerging as key health information sources, concerns about content quality have grown. This study evaluated the quality, reliability, and comprehensiveness of RCI-related videos on TikTok and Bilibili and examined the impact of uploader characteristics. On October 13, 2025, Chinese-language videos containing "rotator cuff injury" were retrieved from TikTok and Bilibili. Following strict inclusion criteria, 231 videos were analyzed. Video characteristics, engagement metrics (likes, comments, shares, collections), and uploader information were collected. Quality and content integrity were assessed using the Video Information and Quality Index (VIQI), Global Quality Scale (GQS), and modified DISCERN (mDISCERN). Statistical comparisons and Spearman correlation analyses were performed. Of 231 videos, 96 were from Bilibili and 135 from TikTok. TikTok videos were shorter (median 93 seconds vs 234.5 seconds, P < .001) but demonstrated higher engagement across all metrics (P < .001). Physicians contributed most content (TikTok: 79%, Bilibili: 64%). Diagnosis and treatment dominated, while epidemiology and prevention were rarely addressed. GQS and mDISCERN scores did not differ between platforms. TikTok scored higher on VIQI information flow (P < .001) and visual quality (P = .044); Bilibili excelled in information accuracy (P = .006). Individual user videos showed slightly higher GQS (P < .05) and accuracy (P = .033); physician videos received more comments (P = .002) and shares (P = .042). VIQI and GQS correlated positively with engagement metrics (VIQI: R = 0.21-0.40; GQS: r = 0.20-0.28; all P < .001), whereas mDISCERN showed weak associations. Video duration correlated positively with quality scores (GQS: r = 0.56; VIQI: R = 0.34; mDISCERN: r = 0.33; all P < .001) but negligibly with engagement. The analysis of RCI-related videos on TikTok and Bilibili reveals moderate content quality and a significant lack of preventive information. These findings underscore the need for strategies to enhance the scientific rigor and comprehensiveness of health information on short-video platforms.