Relationship of Popliteus Sulcus Depth and Tibiofemoral Rotational Alignment with Popliteus Tendinitis in Professional Folk Dancers Exposed to Turnout Positions: An MRI Analysis.

Aims: The popliteus musculotendinous unit plays the major role in range of motion, rotation and stabilization of the knee. Frequent repetition of the rotational strains such as turnout in dancers may be the cause of popliteus tendinitis. In addition, popliteus sulcus depth (PSD) and PSD/lateral condyle width (LCW) ratio are also highly related with popliteal tendinitis in professional folk dancers. In this study, we evaluated the association between clinically diagnosed popliteus tendinitis and PSD with analysis of the PSD/LCW ratio as measured on MRI and tibiofemoral rotational alignment in professional folk dancers. This study was intended to clarify any anatomical liability to popliteal tendinitis in professional folk dancers. Therefore, we looked for the anatomical variances affecting popliteal musculotendinous unit.

Methods: Thirty-two MRI scans from 32 members of a professional folk dance group (mean age 30.2±7.9 yrs, range 18-38) were analyzed retrospectively. Popliteal tendinitis was detected in 5 knees (5 dancers). The relationship of popliteal tendinitis to the tibiofemoral rotational angles (condilary twist angle, posterior codilary angle, posterior tibiofemoral angle), PSD, and PSD/LCW ratio were investigated.

Results: The popliteus tendinitis group had statistically significantly higher PSD and PSD/LCW ratio than the group without popliteal tendinitis (p=0.0001). There was no statistically significant difference between the two groups in the tibiofemoral rotational angles.

Conclusion: In addition to long hours of practice and the turnout position, PSD and PSD/LCW ratio can place the professional folk dancer at increased risk for popliteus tendon injury.