Abstract
Introduction
Total knee arthroplasty is an established and successful operation. In up to 10% of patients who undergo total knee arthroplasty continue to complain of pain [1]. Recently computerised tomography (CT) has been used to assess the rotational profile of both the tibial and femoral components in painful total knee arthroplasty.
Methods
We reviewed 56 painful total knee replacements and compared these to 59 pain free total knee replacements. Datum gathered from case notes and radiographs using a prospective orthopaedic database to identify patients. The age, sex, preoperative Oxford score and BMI, postoperative Oxford score and treatments recorded. The CT information recorded was limb alignment, tibial component rotation, femoral component rotation and combined rotation.
Results
The two cohorts of patients had similar demographics. The mean limb alignments were 1.7 degrees varus and 0.01 degrees valgus in the painful and control groups respectively. A significant difference in tibial component rotation was identified between the groups with 3.2 degrees of internal rotation in the painful group compared to 0.5 degrees of external rotation in the control group (p=0.001). A significant difference in femoral component rotation was identified between the groups with 3.8 degrees of internal rotation in the painful group compared to 1.1 degrees of external rotation in the control group (p=0.001). A significant difference in the combined component rotation was identified between the groups with 6.8 degrees of internal rotation in the painful group compared to 1.7 degrees of external rotation in the control group (p=0.001).
Conclusion
We have identified significant internal rotation in a patient cohort with painful total knee arthroplasty when compared to a control group. There was internal rotation of the tibial component, femoral component and combined rotation. This is the largest comparison series currently in the literature.
