Objective To investigate the method and the cl inical outcomes of reconstruction of the knee stability after resection of tumors of the proximal fibula. Methods The cl inical data were retrospectively analyzed, from 16 patients with tumors of the proximal fibula undergoing proximal fibular resections and reconstructions of the lateral collateral ligament and the tendon of the biceps femoris with anchors between January 2008 and December 2009 (test group). Five patients underwent proximal fibular resection but were not given reconstruction surgery at the same period as the control group. There was no significant difference in gender, ages, disease duration, and tumor site between 2 groups (P gt; 0.05). Lateral stress test was performed after operation; X-ray films were taken to measure the joint space. Musculoskeletal Tumor Society (MSTS) functional score system was used to evaluate the joint function. Results All incisions healed by first intention in 2 groups. Iatrogenic complete peroneal nerve function loss occurred in patients undergoing Malawer type II surgical resection. The patients in both groups were followed up 12 to 36 months, with an average of 30 months. One patient with osteosarcoma of the test group developed local recurrence, and died of lung and systemic metastases after 12 months; the other patients had no recurrence. At last follow-up, the results of knee lateral stress test were negative in the test group, and the joint space increased and was classified as grade A; the results of knee lateral stress test were positive in the control group, and the joint space was classified as grade D. The MSTS score was 97.5 ± 3.5 in the test group and 87.5 ± 3.5 in the control group, showing significant difference (t=2.85, P=0.01). Conclusion The reconstruction of the bony attachment of the lateral collateral ligament and the tendon of the biceps femoris with anchors after resection of the proximal fibula is a safe, rel iable, and simple technique to reconstruct knee stabil ity after resection of tumors of the proximal fibula.