Tenderness over the Pes anserinus and Gerdy's tubercle before and after total knee arthroplasty

Several patients experience chronic pain after total knee arthroplasty (TKA), with the source of postoperative pain attributed to intra- and extra-articular factors. This study focused on the proximal tibia with either the Pes anserinus (PA) or around Gerdy's tubercle (GT) as the most common site of extra-articular pain.

This prospective study included 270 patients (360 knees) with advanced varus osteoarthritis (OA) of the knee scheduled for primary TKA and the patient population comprised 289 women and 71 men with a mean age of 74.7 ± 7.4 years. Operative procedure was performed by a single surgeon. This study investigated the prevalence of PA and GT tenderness over the knee before and after TKA and the association between this tenderness and several factors.

Before TKA, 66.1 % of the patients experienced PA tenderness, whereas 33.1 % experienced GT tenderness. One year after TKA, 49.7 % of the patients experienced PA tenderness, whereas 19.7 % experienced GT tenderness. More than half of the postoperative symptoms in the extra-articular region remained from the preoperative period. Female sex and high body mass index were associated with preoperative and postoperative tenderness of the PA and postoperative tenderness of GT. Postoperative PA and GT tenderness is associated with lower Knee Scoring System 2011 subjective and functional activity scores.

The extra-articular region (PA or GT) is associated with postoperative joint pain and function after knee arthroplasty, and more than half of the postoperative symptoms in the extra-articular region remained from the preoperative period.