Changes of proprioception after total knee arthroplasty

Purpose: Total knee arthroplasty (TKA) is the gold standard procedure to treatments of severe arthrosis which aims to alleviate the pain and restore the locomotor functions. TKA procedure can affect the proprioception which is a significant factor in balance, joint stability and coordination. The aim is to evaluate proprioception and postural control in subject with TKA, before and after the surgery, using Delos Postural Proprioceptive System (DPPS; Delos, Turin, Italy). Methods: This study included 12 subjects (6 women and 6 men; age 67.1±4.9) scheduled for TKA. DPPS was used before and after the surgery. The two tests considered to evaluate postural and proprioceptive control were stabilometric test and static Riva test. Parameters considered were the Stability Index (SI; percentage score based on autonomy and postural instability), Autonomy (AU; percentage score based on hands support) and Postural Instability (PI; score in degree based on movement of trunk). Results: The SI measured during the single stance test improved from 58.3%±22.0 to 71.6%±17.4 with opened eyes and decreased from 36.8%±10.5 to 33.2%±10.2 with closed eyes in the operated limb. PI measured during the double stance test increased of 0.10° with opened eyes and decreased of 0.10° with closed eyes. AU improved with open eyes and slightly decreased with closed eyes. Conclusion: The reduction of pain and the restoration of limb alignment are probably the main reason of the several improvements of SI and AU during open eyes tasks, whereas the lack or ineffectiveness of the proprioceptive system, could be the cause of failure improvement of closed eyes tasks. In TKA, mechanoceptors of the knee are sacrificed, this should result in a drop of the proprioceptive information, and consequently a decreased of balance and increased of risk of falls.