Two hundred and thirty three patients with knee osteoarthritis (OA) were randomized to either thermal or non-thermal rehabilitation, so that the clinical effects of the two treatments could be compared. The primary outcome of interest was VAS pain score at 12 months. On day 21, the final treatment day, there was no significant difference between groups in VAS scores for pain or Lequesne index for function. At 6 months, however, the non-thermal rehabilitation group demonstrated significantly lower VAS pain score, WOMAC pain score, and Lequense index score compared to the thermal group. By 12 month follow-up, the thermal group demonstrated favourable pain outcome through both VAS pain and WOMAC pain compared to the non-thermal group. Functional outcome on the Lequesne Index was not significantly different between groups at 12 months.