Consistency Between Posterior Condylar Axis (+3˚ external rotation) Line and Clinical Transepicondylar Axis Line in Primary Total Knee Arthroplasty

OBJECTIVES: Purpose of this study is to as certain consistency between posterior condylar axis (PCA) + 3˚ external rotation line and clinical transepicondylar axis (cTEA) line in primary total knee arthroplasty cases. MATERIALS-METHODS: During surgery, following distal femoral cut PCA +3 degree external rotation line and cTEA line drawn on the distal femoral cutting surface by ruler and pencil. The both lines on distal femur were recorded by digital camera and relationship between lines was ascertained in reference to PCA +3 degree external rotation [parallel (P), Internal rotation (IR) and External Rotation (ER)]. RESULTS: 9 knees of 9 patients [1 men, 8 women; average age 67 (59-80 age)] were constituted the study group. Evaluation results of the photographs revealed that clinical TEA line in comparison PCA +3 degrees external rotation line was ER in 9 knees (100%) whose mean angles 2.7˚ (1-6) and detected external roation with mean angle 4.7˚ (2-7) in 9 knees. CONCLUSION:: For determination of FC rotation in surgery setting, different results between cTEA and PCA + 3 degrees techniques possibly may due to disadvantages of techniques and anatomic variation of distal femur. Thus, using both techniques for check each other’s results seems unsafe. In custom made prosthesis, which can be done in the future it will be measured by CT. KEYWORDS: Total knee arthroplasty, femoral component, rotational alignment, femoral transepicondylar axis, posterior condylar axis