Frontal plane knee alignment among normal northern Nigerian adults: A radiographic study

Studies have shown that knee alignment parameters differ among races. However, to our knowledge, radiographic frontal plane knee alignment has not been studied in normal northern Nigerian adults. The objective of this study was therefore to determine the frontal plane knee alignment in normal northern Nigerian adults. This study recruited a total of 59 consented subjects (44 males, 15 females). The entire subjects are without any history of lower extremity deformity. Anteroposterior radiographs of both knees with the patella positioned straight ahead were obtained from each participant while standing in a relaxed bipedal stance and placing equal weight on each limb. Alignment was assessed by measuring the tibiofemoral angle (TFA), distal femoral angle (DFA) and proximal tibial angle (PTA). The angles were measured with the aid of a universal plastic goniometre and a plastic ruler. Descriptive statistics of the alignment parameters, independent and paired t-test were computed. In the male population, the mean (standard deviation) obtained were 179.06 (3.87)o for the TFA, 85.94 (3.03 o for the DFA and 89.27 (3.26)o for the PTA. In the female population, the values were 179.53 (3.38)o for the TFA, 86.40 (2.97)o for the DFA and 89.27 (2.15)o for the PTA. No significant mean difference was observed between genders in all the parameters. The TFA does not show any significant difference between the right and left angle regardless of gender. However, significant mean differences were observed in the DFA and PTA of males and combined population. No significant difference was observed in the DFA and PTA of females. Accordingly, northern Nigerian adults may have varus knee alignment compared to other races. Thus, this pre-existing varus alignment should be taken into consideration during clinical examination, preoperative planning and postoperative evaluations of knee deformities in this population.