Postoperative function recovery in patients with endoprosthetic knee replacement for bone tumour: an observational study

Background: The objective of this study is to describe the rehabilitative pathway of patients undergoing endoprosthetic knee replacement surgery, build reference values of the functional results achieved, and identify possible prognostic factors. Methods: Prospective observational study. All patients undergoing resection and knee replacement surgery using a modular prosthesis following bone tumor resection were consecutively recruited over the last 2 years. The patients were followed for a period of 1 year, the result values were collected at 3, 6 and 12 months. Results: In total, 30 patients were enrolled. The median age was 19 years with 33% of patients being female. Median values recorded for knee flexion, quadriceps strength, Toronto Extremity Salvage Score, Time Up and Go and Six Minutes Walking Test showed an improvement of 16, 25, 18, 48 and 38% from 3 to 12 months, respectively. The level and width of the resection were correlated with the mobility of the knee and the strength of the quadriceps. Conclusion: Patients undergoing knee replacement for bone tumors were able to achieve satisfactory functional outcomes from the first postoperative year. A specific assessment of outcomes can be conducted to facilitate the management of patient expectations. A very wide resection and interventions of the proximal tibia are risk factors for a poorer functional outcome.