Which Oxford Knee Score level represents a satisfactory symptom state after undergoing a total knee replacement?

Area of Science:

• Orthopedic Surgery
• Clinical Outcomes Research
• Patient-Reported Outcome Measures

Background:

• Interpreting postoperative Oxford Knee Score (OKS) levels after total knee replacement (TKR) presents challenges.
• Establishing benchmarks for patient satisfaction and treatment success is crucial for evaluating TKR outcomes.

Purpose of the Study:

• To determine Patient Acceptable Symptoms State (PASS) and Treatment Failure (TF) threshold values for the OKS in Danish patients undergoing primary TKR.
• To provide a basis for meaningful interpretation of OKS results in clinical practice and registries.

Main Methods:

• Data from 187-586 patients undergoing primary TKR between 2015-2019 were analyzed from the Copenhagen University Hospital arthroplasty registry.
• Patient responses to the OKS and two anchor questions (satisfactory symptoms, treatment failure) at 3, 12, and 24 months postoperatively were collected.
• Adjusted predictive modeling and non-parametric bootstrapping were used to calculate PASS and TF values with 95% confidence intervals (CI).

Main Results:

• At 3, 12, and 24 months postoperatively, 72-79% of patients reported satisfactory symptoms, while 6-11% reported treatment failure.
• The calculated OKS PASS values were 27 (95% CI: 26-28) at 3 months, and 30 (95% CI: 29-31) at 12 and 24 months.
• The OKS TF values were 27 (95% CI: 26-28) at 12 months and 27 (95% CI: 26-29) at 24 months.

Conclusions:

• Established OKS PASS values provide objective criteria for interpreting TKR outcomes.
• These values can significantly enhance the quality assessment of TKR procedures in both institutional and national healthcare registries.
• The findings support the clinical utility of OKS in evaluating patient-reported satisfaction following total knee replacement.