Association of Thumb Radial Abduction Angle and Hand Grip Strength among Dental Students

Abstract

Background: Dental professionals, particularly dental students, are at high risk of developing upper limb musculoskeletal disorders due to the repetitive and static nature of their clinical tasks. Maintaining fixed postures while using hand instruments can lead to fatigue, strain, and reduced dexterity, affecting grip strength and hand function. Objective: To determine the relationship between thumb radial abduction and hand grip strength in dental students and house officers. Methodology: A multicenter analytical cross-sectional study was conducted at CMH Medical College and the Institute of Dentistry, Lahore. The study population included undergraduate dental students (3^rd and 4^th year), house officers, and postgraduate trainees aged 23 to 26 years with intact hands and no upper limb deformities. Participants with a history of wrist or hand injury within the past year, previous fractures, arthritis, neurological disorders affecting the upper limbs, or persistent wrist pain were excluded. A total of 266 participants were recruited using convenience sampling, with the sample size determined via Yamane’s formula. Hand grip strength was measured using a calibrated digital Jamar dynamometer. Thumb radial abduction angles were measured using a universal goniometer. Continuous variables were assessed for normality using the Shapiro-Wilk test. Descriptive statistics were reported as mean ± standard deviation or median with interquartile range for continuous variables, and frequencies and percentages for categorical variables. Spearman’s rank correlation coefficient was used to assess associations between hand grip strength and thumb radial abduction angles due to the non-normal distribution of the data. Subgroup analyses by gender and hand dominance were also performed using Spearman’s correlation. Results: The mean thumb radial abduction range among dental students was 35.2±4.3°, and 36.5±3.8° among house officers. The mean hand grip strength was 38.4±6.2 kg for dental students and 40.1±5.4 kg for house officers. A significant positive correlation (r=0.68, p<0.01) was found between thumb radial abduction and hand grip strength, indicating that greater thumb abduction is associated with enhanced grip strength. Conclusion: Thumb radial abduction shows a significant positive correlation with hand grip strength among dental professionals. Improving thumb mobility and grip strength may help to reduce the risk of upper limb musculoskeletal disorders.