Difference in daily tasks execution and elbow joint load: a comparison between patients after total elbow arthroplasty and healthy controls

Background: Overloading of the elbow joint is one of the mechanisms responsible for failure of total elbow arthroplasty (TEA). Different activities of daily living (ADL) affect joint loading. However, the alteration in task execution and its impact on joint loads after TEA are not well understood. This study investigates differences between TEA patients and healthy controls in task execution and associated joint loads during simulated ADL. 

Methods: TEA patients (n = 7) and healthy controls (n = 18) performed 8 simulated ADL tasks. Using musculoskeletal modeling software (OpenSim), joint angles and moments were calculated and joint power was assessed. A mixed model statistical design was performed to determine group and tasks differences.

 Results: TEA patients showed reduced flexion–extension (FE) range of motion (60.6° ± 25.6 vs. 44.9° ± 19.9, P = .003). Interaction effects between groups and tasks for joint load and peak power were observed. Particularly during rising from a chair, patients showed reduced FE moment (5.7 Nm vs. 14.5 Nm, P = .026), varus-valgus moment (6.0 Nm vs. 14.3 Nm, P = .036), and peak power (3.6 Watt vs. 20.1 Watt, P = .036) compared to healthy controls. 

Conclusion: TEA patients differ from healthy controls in task execution of ADL tasks regarding the functional elbow FE angle over all 8 ADL tasks and in joint load and peak power for the more straining tasks. The power plots visualizes differences in movement strategy that are of interest for future research on possible training of TEA patients, or prosthesis design, aimed to improve ADL function and enhance prosthesis survival rates.