Popliteus Tendon Release in the Varus or Neutral Knee: Prevalence and Potential Etiology

Abstract

Total knee arthroplasty has proven to be a highly successful procedure over the past four decades, with reported survivorship rates surpassing 90% for the various implant designs. Several factors are known to correlate with a well-functioning total knee arthroplasty, including implant design, component fixation, mechanical alignment, and soft-tissue balancing. Balancing the soft-tissue envelope surrounding a total knee arthroplasty has proven to be a particularly strong determinant of function. In fact, some authors have pointed out that a successful total knee arthroplasty may be most appropriately characterized as a soft-tissue operation1,2. Over the past two decades, several investigators have examined the role of individual soft-tissue structures relative to soft-tissue balancing after total knee arthroplasty and the effects of selective soft-tissue releases on knee stability after a total knee arthroplasty procedure1-9. The overriding goal of many of these studies was to direct selective (rather than global) release of tight muscular, tendinous, capsular, or ligamentous structures to provide soft-tissue balance while avoiding instability. Although some work on medial release sequences for the varus deformed knee has been accomplished, the majority of attention to soft-tissue balancing has been paid to the valgus knee1-9. With regard to the valgus knee, we now recognize that certain soft-tissue structures (such as the iliotibial band) predominantly affect the extension gap, while others (such as the popliteus tendon and the posterior cruciate ligament) predominantly affect the flexion gap. Selective release of the popliteus tendon to obtain a balanced flexion gap during total knee arthroplasty has been reported by several authors, including Ranawat et al. and authors from our center1,2,6,7. In contrast, popliteus tendon release in the varus or neutral knee has not been well described, despite the occasional necessity …