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Background: In the clinic, patients with endoprosthetic knee replacement for bone tumour generally experience loss of neuromuscular control and body balance, which consequently affects knee function and quality of life. Active physical exercise (APE) has been proven to be effective in rehabilitation. However, in the literature, no systematic study has been performed to make a general guideline of APE training on the patients.

Methods: A total number of 528 patients who have had endoprosthetic knee replacement for tumour resection was collected from July 2009 to December 2016. After operation, the patients were randomly attributed to rehabilitation of either APE training or conventional continuous passive motion (CPM) for six months. The APE training was specific for patients with a bone tumour on the distal femur (APE-F) and the proximal tibia (APE-T), and the whole training was divided into three stages with different training items and training intensity which was progressively increased with limited intensity in terms of metabolic equivalent (MET) level for each stage. For each individual patient, the APE training intensity was personal based on personal basic MET. The patients were followed up for five years for regular assessments of functional knee recovery and quality of life.

Findings: Both APE training and CPM training induced significant improvements in functional knee recovery and quality of life throughout the whole period of follow-up. Nevertheless, the improvements were more significant in patients following APE training than in that following CPM training (APE-F vs. CPM-F and APE-T vs. CPM-T). Additionally, the specific APE training induced significantly better functional knee recovery throughout the whole five-year of follow-up, and quality of life in the first six-month post-operation in patients of APE-F than in that of APE-T. In contrast, the CPM training induced significantly better improvements in both functional knee recovery and quality of life the whole five-year of follow-up. Nevertheless, the early APE training, especially for the patients of APE-T, did not induce more incidence of complication of any type compared to CPM training (APE-F vs. CPM-F and APE-T vs. CPM-T).

Interpretation: APE training is more effective in improving functional knee recovery and quality of life than CPM training. The results observed in patients of APE-T and APE-F in comparison to that of CPM-F and CPM-T demonstrates further the advantage of APE training over CPM training in rehabilitation. The low complication incidence following APE training is attributed to the well-controlled training intensity through personal MET. Taken together, the study provided strong evidence for clinical application of APE training on the patients.