The purpose of this study was to analyse the effects of preoperative physiotherapy on pain and function in 39 patients scheduled for unicompartmental prosthetic knee replacement. Nineteen patients were selected at random to receive preoperative physiotherapy. The control group received no preoperative therapy. Evaluations were performed 3 months prior to surgery, immediately before and 3 months after operation. Evaluations included: Clinical assessment, measurements of the knee muscle strength, self-selected walking speed and the oxygen cost of walking. Three months before surgery the patients in both groups had similar types and levels of problems. Before surgery patients who had received physiotherapy showed slight improvements in pain, perceived stability of the knee during walking, and faster self-selected and maximal walking speeds compared to the control group, but were unchanged in muscle strength, ROM, and oxygen cost. Three months after surgery pain was significantly decreased in all patients, however, no significant differences were found between the two groups for any variable except muscle strength. This was unchanged compared to preoperative values for patients of the control group while patients who received preoperative physiotherapy showed a decrease in strength. In summary, this study did not disclose any major benefit from the program of preoperative physiotherapy tested.