QUESTION: Following a total knee replacement (TKR) or total knee arthroplasty (TKA), a patient has valgus angulation of 10°. When rating the resulting impairment using Table 17-35, Rating Knee Replacement Results (5th ed, 549) of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fifth Edition, is it correct to make an alignment deduction of 30 points (3 points for each of the 10° of valgus)?
ANSWER: The answer is not as simple as it may seem. The post-TKA knee reportedly has 10° of valgus alignment (also known as knock knee); however, the question does not state whether this measurement was made on physical examination or using a radiograph. The most accurate method for measuring lower limb alignment in the frontal (coronal) plane would be a full-length, standing anteroposterior radiograph, with the patella centered between the...
