Numbness Following Total Knee Arthroplasty: Role of Incision Length And Position - A Randomized Study

BACKGROUND: One of the symptoms annoying patients after total knee replacement (TKR) is numbness around the operative scar. Some studies have shown that altering the incision in terms of placement or length may decrease the incidence of numbness. It still remains unknown whether numbness affects patient-reported outcomes. METHODS: We conducted a randomized study to compare a short-length incision (n = 50) and a lateral exit incision (n = 50) with a standard midline TKR incision (n = 50) in terms of the incidence of numbness and its progress over 1 year of follow-up. Our secondary objective was to look at the involved zone, area of numbness, and secondary symptoms. We also looked at patient-reported outcome in terms of satisfaction in all groups using a visual analog scale and Forgotten Joint Score. RESULTS: At 3 months postoperatively, the incidence of numbness was least in the lateral exit group: 46.2% as compared to midline (62%) and short (58.3%), but the difference was not significant (p = 0.07). At 6 months, the short incision group had a significantly lower incidence (8%) of residual numbness as compared to 30% in the other two groups (p = 0.003). At 1 year, most patients recovered sensation loss and had similar function. CONCLUSIONS: Placement or length of an incision did not significantly affect the incidence of numbness; however, the short incision led to early recovery of numbness. At 1 year of follow-up, most patients did not complain of loss of sensation and had similar functional outcome.