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Progressing toward, and recovering from, knee replacement surgery: a five-year cohort study.

OBJECTIVE
To determine the trajectories of preoperative worsening and postoperative recovery for both the index knee and the contralateral knee of patients undergoing knee replacement surgery.


METHODS
Of the 4,796 subjects in the Osteoarthritis Initiative cohort study database, we examined 5-year data from 177 patients who underwent isolated unilateral knee replacement surgery and no other joint replacement surgery. Patient-reported outcomes captured domains defined by the International Classification of Functioning, Disability, and Health. Domains of knee structure and function, activity limitation, and participation restriction were examined using growth-curve modeling over 5-year periods prior to and following surgery.


RESULTS
Preoperative worsening of the index knee was substantial in all domains of knee impairment, activity limitation, and societal participation. Pain intensity worsened only slightly from 5 years to 2.5 years prior to surgery, but worsened by ∼2 points (0-10-point scale) during the 2.5 years prior to surgery. Trajectories of improvement following surgery varied depending on the outcome measure. The contralateral knee also changed over time, such that by ∼2 years following surgery, pain was worse and by 3 years, activity limitation was worse in the contralateral knee as compared to the index knee.


CONCLUSION
Patients who elect to undergo knee replacement surgery demonstrate perioperative trajectories of change that influence most health domains for both the index knee and the contralateral knee. After a period of no change, escalation of pain and worsening functioning in the index knee begins ∼2.5 years prior to surgery, which may be a key trigger for surgery.