Clock Drawing Performance Slows for Older Adults After Total Knee Replacement Surgery

Area of Science:

• Neuroscience
• Cognitive Psychology
• Orthopedic Surgery

Background:

• Clock drawing is a key neurocognitive screening tool used preoperatively.
• This study investigates changes in clock drawing performance post-total knee arthroplasty (TKA).

Purpose of the Study:

• To examine changes in clock drawing test performance (command and copy) at 3 weeks and 3 months after TKA.
• To compare post-TKA changes with a nonsurgery control group.

Main Methods:

• 67 TKA patients and 66 controls (>60 years) completed a digital clock drawing test pre- and post-surgery.
• Generalized linear mixed models assessed latency and graphomotor output.
• Reliable change analyses identified significant performance shifts compared to controls.

Main Results:

• TKA patients showed significantly slower clock drawing latency (completion time) compared to controls, adjusting for baseline cognition.
• Three weeks post-TKA, 25% of patients were slower on command and 21% on copy tests.
• At 3 months, 18% of TKA patients remained slower than controls; graphomotor measures did not change significantly.

Conclusions:

• Clock drawing speed decreased significantly in a substantial portion of TKA patients, unlike controls who showed practice effects.
• These findings highlight potential neurocognitive impacts of TKA surgery.
• Further research is needed to explore the neurobiological underpinnings of these observed changes.