Pes anserinus pain syndrome following total knee arthroplasty for degenerative varus: incidence and predictors

Purpose

Pes anserinus pain syndrome (PAPS) is a well-described condition in the native knee; however, its incidence after total knee arthroplasty (TKA) is unknown. This study aimed to determine the incidence of PAPS after primary TKA, identify potential risk factors, and assess its response to treatment. Few case reports have been published until now; to our knowledge, ours is the first study assessing the incidence and predictors of post-TKA PAPS.

Methods

A total of 389 primary TKAs performed for degenerative varus knee at a single institution by the same surgeon were analyzed. We recorded demographic variables, medical comorbidities, and clinical, radiographic, and surgical data. Specific predictors of interest were compared between post-TKA PAPS and controls.

Results

The incidence was 5.6% (22/389). On univariate analysis, female sex (p = 0.03), body mass index (BMI) (41.3% ± 7.9; p < 0.001), and absence of pes anserinus release (p = 0.04) were significant predictors. On multivariable regression analysis, only BMI was a significant independent risk factor (p = 0.01). All patients were treated non-operatively; 81.8% responded to nonsteroidal anti-inflammatory drug–physical therapy program and 18.2% required an additional local steroid injection.

Conclusion

PAPS occurs after TKA; the incidence was found to be 5.6%. BMI seems to be an independent risk factor. It is a benign condition and can be effectively treated conservatively in most cases.