The Effect of Numbness on Outcome from Total Knee Replacement

Introduction Some patients report continuing pain and functional limitations after total knee replacement (TKR). Whilst numbness around the TKR scar is common, the impact of numbness is less clear. One particular activity that could be influenced by numbness is kneeling. The aim of this study was to explore the impact of numbness around TKR scars on health-related quality of life and kneeling ability. Materials and Methods We recruited 56 patients one year after primary TKR. Sensation around the knee was assessed through patient self-reporting, monofilament and vibration and their distress measured on a visual analogue scale (VAS). Patient-reported outcome measures (PROMs) including WOMAC, painDETECT, EQ-5D and KOOS were used. Participants were asked about kneeling ability. Results Whilst 68% of patients reported numbness around their TKR scar, we found no statistically significant correlation between numbness and distress at numbness (self-report 0.23 (p=0.08), monofilament 0.15 (p=0.27)). We also found that numbness does not correlate statistically significantly with joint-specific PROMs (WOMAC 0.21 (p=0.13) and KOOS 0.18 (p=0.192)). However, difficulty with kneeling did correlate with both self-reported numbness (0.36, p=0.02) and worse PROM scores (WOMAC pain 0.62, p<0.001 and KOOS 0.64, p<0.001). Discussion and Conclusion Numbness after knee replacement is common, but is not associated with worse patient reported outcomes.