Overview
This prospective observational cohort study aims to investigate the association between preoperative multimorbidity burden and functional recovery after primary total knee arthroplasty (TKA) in patients with knee osteoarthritis.
Approximately 230 adult patients undergoing elective unilateral primary TKA will be enrolled at a single hospital in Türkiye. Preoperative multimorbidity burden will be assessed using the Functional Comorbidity Index (FCI), which measures the presence of medical conditions that may affect physical function.
Patients will be evaluated before surgery and at 6 and 12 months after surgery. Functional outcomes and pain will be assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Oxford Knee Score (OKS). Anxiety and depressive symptoms will be evaluated using the Hospital Anxiety and Depression Scale (HADS).
The primary objective is to determine whether higher preoperative multimorbidity burden is associated with poorer physical function at 12 months after TKA. The study will also examine changes in functional recovery over time and other clinical outcomes.
All surgical procedures, postoperative care, and rehabilitation will follow routine clinical practice. No additional treatment or experimental intervention will be assigned as part of this study.
Description
Total knee arthroplasty (TKA) is an effective surgical treatment for advanced knee osteoarthritis, providing substantial improvements in pain and physical function. However, the extent and trajectory of postoperative recovery vary considerably among patients. Preoperative multimorbidity may influence recovery, although previous studies have reported inconsistent findings regarding its association with postoperative functional improvement.
This single-center, prospective observational cohort study will evaluate the relationship between preoperative multimorbidity burden and functional recovery after elective unilateral primary TKA.
A target sample of 230 adult patients undergoing primary TKA for knee osteoarthritis will be consecutively enrolled. The sample size accounts for potential loss to follow-up, with a target of at least 166 patients completing the 12-month assessment.
Preoperative multimorbidity burden will be evaluated using the Functional Comorbidity Index (FCI), an 18-item index developed to assess comorbidity burden in relation to physical function. Comorbid conditions will be identified through patient interviews and verified using medical records and medication histories.
Patient-reported outcomes will be collected preoperatively and at 6 and 12 months postoperatively. The WOMAC will assess pain, stiffness, and physical function, while the Oxford Knee Score (OKS) will provide an additional assessment of knee-related pain and function. The Hospital Anxiety and Depression Scale (HADS) will assess psychological symptom burden.
The primary outcome will be the WOMAC physical function subscale score at 12 months after surgery. Secondary assessments will examine longitudinal changes in WOMAC scores, OKS, HADS, knee range of motion, patient satisfaction, postoperative complications, hospital readmissions, manipulation under anesthesia, and revision surgery.
All patients will receive posterior-stabilized primary knee prostheses and follow the institution's standard postoperative rehabilitation protocol. Surgical procedures will be performed by orthopedic surgeons according to routine clinical practice. No additional treatment or alteration to standard care will be introduced for research purposes.
The primary analysis will assess the association between baseline FCI score and 12-month WOMAC physical function score using multivariable linear regression, adjusting for prespecified clinical
Eligibility
Inclusion Criteria:
- Adults aged 18 years or older.
- Scheduled for elective unilateral primary total knee arthroplasty due to primary knee osteoarthritis.
- Sufficient cognitive and communication abilities to understand and complete the study questionnaires.
- Provision of written informed consent for study participation.
Exclusion Criteria:
- Patients scheduled for revision total knee arthroplasty.
- Patients scheduled for simultaneous bilateral total knee arthroplasty.
- Arthroplasty indicated for inflammatory arthritis, tumor, infection, or post-traumatic conditions.
- Severe cognitive impairment, advanced dementia, or communication difficulties preventing valid completion of the study questionnaires.
- Significant logistical or legal circumstances preventing completion of the planned follow-up assessments.


