Aim: The point of time for total knee arthroplasty has a significant importance due to limited implant survival rate. To what extent the preoperative stage of physical and psychological function limitation, which is increasing with the progression of the osteoarthritis, has an influence on the early functional outcome after total knee arthroplasty should be clarified in a clinical evaluation.
Patients and method: 47 Patients were treated with the same bicondylar knee endoprosthesis system (Type Genia, ESKA Implants, Lübeck). A clinical evaluation was undertaken preoperatively and at 3 and 6 months postoperatively using HSS score, WOMAC index and SF-36 score. In relation to the preoperative HSS score the patients were allocated into three groups depending upon whether their level of function was "good", "average" or "poor". Additionally, all patients were assigned to three body mass index (BMI) groups (< 30, 30 - 35, > 35) which were descriptively analysed.
Results: The preoperative differences in HSS score and SF-36 score in all three groups show a high reduction after 3 and 6 months. Postoperatively there were no significant differences in all three groups at both timepoints. Patients with "poor" preoperative function achieved on average a lower score niveau than patients with preoperative "good" function, but have the benefit of the best function improvement. The early postoperative period (3 months) showed the highest decrease in physical and psychological function derogation. The BMI had no significant influence on the early functional outcome.
Conclusion: Therefore, older people should receive early total knee arthroplasty to gain a high postoperative score niveau. In younger patients the indication for implant should be considered essentially because of the limited survival rate. Even in progressive osteoarthritis and extreme functional limitation the bicondylar surface replacement gives the possibility of a good early functional postoperative outcome. Total knee arthroplasty of obese patients is under attention of the perioperative internistic risks, a safe procedure with good functional results and can increase patient's mobility.