Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Context: The posterior femoral offset may significantly impact the final flexion range after total knee arthroplasty (TKA). The purpose of the present study was to compare a conventional, radiologic-based technique with an intra-operative, surgical navigation-based technique for the measurement of posterior femoral offset. The tested hypothesis was that the two measurement techniques produce different results both before and after TKA.', 'One-hundred consecutive cases referred for end-stage knee osteoarthritis have been studied. Posterior femoral offsets, measured pre- and post-TKA from radiographs, as well as those measured from a navigation system intra-operatively, were analysed. The pre-TKA measured offsets, post-TKA measured offsets and the changes (pre- vs. post-TKA) in the offsets were statistically compared between the radiologic and the navigated measurement techniques at a 0.05 level of significance.', 'The mean paired difference between pre-TKA radiologic and navigated measurement was 44mm (p<0.001). There was a significant and moderate positive correlation with a good coherence between the two measurements. The mean paired difference between post-TKA radiologic and navigated measurement was 65mm (p<0.001). There was a significant and moderate positive correlation but a poor coherence between the two measurements.
Answer: The conventional radiologic technique for the measurement of the posterior femoral offset cannot be reliably used either for pre-TKA planning of the posterior femoral resection and antero-posterior sizing of the femoral component, or for post-TKA quality control of the reconstruction of the posterior femoral offset.
Is radiographic measurement of the posterior femoral offset precise?