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Patients Prefer Function over Motion after Knee Replacement

How do you know if a total knee replacement is successful? Is it measured by the amount of knee range of motion (ROM)? Function? Patient satisfaction and quality of life? Actually, researchers use all three measures. ROM may be the most important because it affects the patient's ability to use the knee.

This study looks at the role of knee ROM one year after knee replacement. The procedure used to replace the knee joint is called total knee arthroplasty (TKA). Patient satisfaction and quality of life (QOL) are also included as important measures of success.

Patients in 12 centers from the United States, United Kingdom, and Australia were included. This was the first TKA for each patient. Everyone had knee osteoarthritis and received the same type of replacement implant.

Studies show that people use 45 to 105 degrees of knee flexion for daily activities. The authors report that patients unable to bend their knee more than 95 degrees have worse function than those patients who can flex more than 95 degrees.

In this study, however, patient satisfaction and QOL are based on the ability to use the knee. Actual knee flexion didn't seem to matter as much. Patients with problems in the other knee or the hip on the same side had less knee motion in the TKA knee. Notably, patients with a stiff knee can compensate better than those with a stiff hip.

The authors conclude that success after a TKA can be based on the patient's report. Actual knee flexion doesn't seem to be as important as getting around during daily activities.

References: Andrew L. Miner, BS, et al. Knee Range of Motion after Total Knee Arthroplasty. In The Journal of Arthroplasty. April 2003. Vol. 18. No. 3. Pp. 286-294.

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