Do Knee Pain Phenotypes Have Different Risks of Total Knee Replacement?

Area of Science:

• Orthopedics
• Pain Medicine
• Rheumatology

Background:

• Osteoarthritis (OA) pain is a primary driver for seeking healthcare, including total knee replacement (TKR).
• OA pain is complex, influenced by peripheral, psychological, and neurological factors, suggesting distinct patient subgroups.
• Previous research identified three OA pain phenotypes based on emotional status, structural damage, and other factors.

Purpose of the Study:

• To investigate if distinct OA pain phenotypes are associated with varying risks of undergoing TKR over a 12-year period.
• To determine if pain phenotype is a predictor of TKR, independent of other clinical factors.

Main Methods:

• Utilized data from 963 participants in a population-based cohort study (mean age 62.8 years).
• Collected data on socio-demographics, psychological status, comorbidities, and knee structural damage via MRI.
• Applied latent class analysis to identify pain phenotypes and Cox proportional hazards models to assess TKR risk over 12 years.

Main Results:

• Participants in Class 1 (high emotional problems, low structural damage) and Class 2 (low emotional problems, high structural damage) exhibited significantly higher TKR risks compared to Class 3 (low emotional problems, low structural damage).
• Hazard ratios for TKR were 4.81 for Class 1 and 9.23 for Class 2, relative to Class 3.
• These associations were significant for both the imaged right knee and the contralateral left knee.

Conclusions:

• Distinct osteoarthritis pain phenotypes are associated with differential risks for total knee replacement.
• Pain phenotype, particularly emotional distress, appears to be a stronger predictor of TKR than structural joint damage.
• These findings suggest that optimizing patient selection for TKR may improve clinical outcomes by considering distinct pain phenotypes.