Is Popliteus Tendon a Redundant Structure in Total Knee Arthroplasty?

Many studies have shown that injury to the popliteus tendon has little consequence for the static stability of the knee following total knee arthroplasty (TKA). However, very few studies have evaluated the effect of intraoperative iatrogenic popliteus tendon injury on the patient-reported outcome measures (PROMs) following TKA. This study aimed to determine the incidence of iatrogenic popliteus tendon injury in our subset of the population and to find out its effect on PROMs.

100 consecutive osteoarthritic varus knees with flexion deformities less than 20° were operated upon by a single senior experienced arthroplasty surgeon. Patients were assessed intraoperatively for any iatrogenic popliteus tendon injury, the injury site, and the amount of injury which was quantified and graded. PROMs applied for assessment at 1-year follow-up were Knee Society Score (KSS 1), Knee Function Score (KSS 2), and Western Ontario and McMaster University Osteoarthritis Index (WOMAC).

17% of cases had an iatrogenic popliteus tendon injury. Thirteen had grade II injuries, whereas four had grade III injuries. There was no statistical significance in post-operative knee mobility and PROMs among those with popliteus tendon injury versus non-injured patients.

The incidence of iatrogenic popliteus tendon injury is higher than what we expected. The tendon injury remains a risk, but it is unclear how the popliteus tendon injury will affect patients after the TKA. In our series, such an injury during knee replacement does not affect the functioning of the knee in the short term; however, a long-term follow-up is warranted.