One hundred one adults with chronic lumbar osteoarthritis/spondylosis (chronification stage 1–2) were randomized in a multicenter, double-blind, controlled trial to receive either conventional inpatient rehabilitation plus nightly traction-bed therapy (intervention group) or conventional rehabilitation with a sham traction device (control group). All patients underwent a standardized 3-week rehabilitation program; the intervention group additionally received active traction for 5–8 hours nightly over 21 consecutive days. The primary outcome was pain reduction measured by the Numerical Rating Scale (NRS). Secondary outcomes included disability (Roland–Morris Disability Questionnaire), functional lifting capacity (PILE test), morning start-up time, finger-floor distance, and quality of life (SF-36). Overall, the results of the study revealed that both groups improved with rehabilitation; however, the traction-bed group demonstrated significantly greater pain reduction at discharge, superior improvements in disability and functional outcomes, and better quality-of-life scores. These findings suggest that prolonged low-load traction applied overnight can enhance short-term rehabilitation outcomes in patients with chronic lumbar spondylosis.