Determination of Carrying Angle of Elbow Among Adult Pakistani Population

Abstract

To determine the carrying angle of elbow among adult Pakistani population presenting to a tertiary care hospital. The elbow joint is a compound synovial joint consisting of the distal humerus, proximal radius and ulna with two articulating surfaces, humeroulnar and radioulnar joints. The average value of the carrying angle is considered 12.5 ±0.57 degrees in males and 15.26 ±0.45 degrees in females. Determination of carrying angle in our population will assist in better understanding of elbow biomechanics, improvement in prosthesis designs and development of pre contoured anatomic implants for our population. This Descriptive cross-sectional study was done at The Indus Hospital Karachi, a free of cost tertiary care facility, for a period of six months after approval from IRB. Population who met with inclusion criteria were recruited and carrying angle of both elbow and length of forearm measured with the help of Goniometer and inch tape respectively. The data were entered in SPSS V.24.0 and analyzed using SPSS and R studio. . Mean ±SD/Median (IQR) were computed for all the categorical variables as appropriate. Kruskal Wallis/ANOVA was applied as appropriate to assess significant difference in age, height, weight, carrying angle, length of arm and extension among ethnicities. Independent sample T-test/Mann-Whitney U test was applied as appropriate to assess significant difference in aforementioned quantitative variables between both the genders. Furthermore, linear quantile model was applied to assess significant difference in carrying angle for all the pairwise combination of ethnicity adjusting for age, height, weight and gender. Wilcox signed rank test was applied to assess dominant hand wise significant difference in right and left hand carrying angle. All the categorical variables were presented as frequency along with percentage. P-value<0.05 was considered statistically significant. A total of 500 participants were enrolled in the study, out of which 353 (70.6%) were males, 142 (28.4%) were females and 5 (1%) had missing information regarding gender. Approximately, half of the patients were Urdu speaking (49.2%) followed by Punjabi (16%), Sindhi (12.4%) and Pathan (9.2%) (Figure-2). Majority (96%) of the patients had right dominant limb and only 4% had left dominant limb (Figure-3). Men were found to be significantly taller and heavier than women (Median: 167 vs 155 cm, 65 vs 56.5 kg, respectively p=<0.0001. However, no significant differences were observed in BMI between both the genders (p=0.291). Men had longer median length of forearm as compared to women (p<0.0001). Women were found to have higher median of upper limb carrying angle as compared to men (p<0.0001). Also, the distribution of extension of arms was found more variable in women than men (p=0.002 and 0.023). Punjabis had higher carrying angle followed by Urdu speaking, Pathan and Sindhi adjusting for age, height, weight and gender. Right dominant hands had higher right hand carrying angle in comparison to left hand (Median (IQR): 10 (8-13) vs 10 (8-12), p=0.000). Whereas it was not true for left dominant hand. (Median (IQR): 10 (8.2-12) vs 10 (8-12), p=0.880 Mean carrying angle in male was 9.5 ± 3.1 degree (dominant hand), whereas for female was 14.4 ± 3.2 degrees (dominant hand). This is consistent with published literature. The carrying angle of right elbow was higher in right hand dominant people, whereas it was not true for left hand dominance. This is statistically significant difference as compared to previous literature. We recommend a larger scale multicentric study to further substantiate our findings in our population.