Thirty-five patients were prospectively examined on average 5.9 and 11.1 months after reconstruction of the anterior cruciate ligament. Eighteen patients were treated postoperatively with a regular physiotherapy (PT) program 2-3 times per week for 30 min, 17 patients with a special, extended, and supervised rehabilitation program 3-5 times per week for 2.5 h. Criteria for exclusion from this study were previous operation or fractures of the affected knee. The bases for the evaluation of the clinical results were the clinical examination, the Lysholm and Tegner scores, KT 1000, angular reproducibility according to Barrett (proprioception), and the figure-of-eight hop test. It appeared that patients treated with extended ambulatory physiotherapy (EAP) gained a significantly higher degree of functionality in the Lysholm score after 5.9 months (p < 0.02) and the Tegner score after 11.1 months (p < 0.05) than patients treated with regular physiotherapy. Patients treated with EAP also displayed better results in the proprioceptive capability test with an angular deviation of 5.8 degrees after 5.9 months compared to 11 degrees in patients receiving regular PT. After 11.1 months, there were no differences in proprioceptive capability between the two groups. Although the EAP patients were faster in the figure-of-eight hop test (0.39 s difference compared to 0.58 s in the PT patients), the results were not statistically significant. In KT 1000 ventral tibial instability was on average 21% lower in the PT patients than in the EAP patients. After 11.1 months, both groups exhibited the same median value of 3 mm. Furthermore, EAP patients were able to return to work after 36.7 days on average, a 35% shorter period than in the case of PT patients (55 days), also of statistical significance (p < 0.02). To conclude, the primarily higher costs of this intensive rehabilitation program are justified by the better functional outcome linked with an earlier return to work.