Distal radius fractures are a common orthopedic injury that accounts for every six fractures diagnosed and treated in emergency departments (Pennock et al. 2005). Knowledge of average values of distal morphometry is essential, as one of the goals of fracture treatment is to reconstruct the anatomical configuration (Jupier and Masem, 1988). The quality of reduction is mainly evaluated by the radial inclination angle and the degree of restoration of the palmar tilt (van Earten et al., 2008). Radial shortening increases radial inclination, and dorsal angulation causes significant changes in wrist joint kinematics and grip strength (Gupta et al., 2015).
In 1987 Short et al. In a cadaveric study demonstrating the importance of palmar tilt, increased dorsal angulation was shown to increase the load passing through the ulna. Loss of radial height and radial inclination results in significant axial load transfer from the radius to the ulna. Loss of palmar tilt reduces the area of contact of the distal articular surface with the scaphoid and lunate (Short et al., 1987). These changes can cause post-traumatic osteoarthritis, midcarpal instability, and pain. In addition, loss of palmar tilt weakens grip strength and causes distal radioulnar joint incompatibility, which tightens the interosseous membrane and limits forearm rotation (Caputo et al., 1998). Based on these findings, guidelines have been created that determines the amount of malalignment a patient can tolerate. In general, fractures that result in a radial height loss of more than 2 mm, radial inclination changes of more than 5°, and a loss of palmar tilt of more than 10° require reduction (Van Riet et al., 2004).
When the study data were compared with the Orthopedic Trauma Association (OTA), The usual range of the radial inclination value is considered to be between 13–20° in OTA. In the Anatolian population, this value was found to be 23.35°. While the normal range of palmar tilt value was accepted as 1–21°, it was 15.7° in the Anatolian population. While the average value range of radial height is taken as 11–13 mm, this value was 10.55 mm in the Anatolian population. While ulnar variance was considered neutral in OTA, it was found to be negative variance in the Anatolian population. While all DER values are within the normal range according to OTA, only the ulnar variance differs from the value accepted by the Anatolian population.
Avascular necrosis of the lunate, avascular necrosis of the scaphoid, and negative ulnar variance area on scaphoid-lunate dissociation have been demonstrated in previous studies (De Smet, 1994). Gelberman found that negative ulnar variance was responsible for Kienbock's disease, more common in whites (Gelberman et al., 1975). Conversely, positive ulnar variance causes overload on the ulnar compartment, resulting in triangular fibrocartilage complex (TFCC) degeneration and degeneration of other carpal bone cartilage. Decreased radial height has been found to impair TFCC and cause significant discomfort in kinematics around the wrist. Although it caused this discomfort in changes in radial inclination, it was not as effective (Adams, 1983).
In our study, when DER values were compared between genders, radial height was higher in males, a significant difference. There is no significant difference between other values (Table 2). Mishra et al. (2016) are similar to the results found.
When the ulnar variance values are compared, there is no significant difference between the genders. The highest rate of negative variance and the least rate of neutral variance were found in men and women (Table 3). Nekkanti et al. In their study, the highest neutral variance in men and women and the least positive variance was found. In our study, mean ulnar variance was observed in 54 patients (43.54%), negative variance, positive variance in 52 patients (41.9%), and neutral variance in 18 patients (14.56%). The OTA reference value for ulnar variance is neutral variance. Chan et al. (2008) observed that the mean ulnar variance had a positive variance of 0.13 ± 0.72 mm. Mishra et al. (2016) observed a positive ulnar variance of 0.66 ± 2.46 mm in their study of the Indian population. However, the tendency for negative ulnar variance was higher in our study. There was a positive ulnar variance trend in the second rank, and the least neutral variance was found.
When DER values were evaluated according to age, no significant difference was found between radial inclination, palmar tilt, and radial heights; however, in the Anatolian population and Nekkanti et al. (2018) compared the data in their study with the Indian population; While the radial inclination of the Anatolian population was found to be 23.51°±2.06 in the 17–29 age group, 23.25°± 1.52 in the 30–59 age group, 22.78°± 2.52 in the 60 ≤ age group, in India it was 21.83° ±3.56 in the 30 ≤ age group, and in the 31–60 age group. It was found as 21.46°± 3.04, 21.08°±3.78 in the 60 ≤ age group. Radial height in the Anatolian population by age; While was found to be 10.67 mm ± 4.21 in the 17–29 age group, 10.45 mm ± 4.49 in the 30–59 age group, 10.34 mm ± 4.82 in the 60 ≤ age group. In the Indian population, 9 mm ± 0.28 in the 30 ≤ age group, 8.8 mm ± 0.26 in the 31–60 age group, 8.2 mm ± 0.23 in the age group of 60 ≤. Palmar tilt was found to be in the Anatolian population 15.71°±3.03 in the 17–29 age group, 11.43°±3.28 in the 30 ≤ age group, 11.42°±3 in the 31–60 age group, 10.64°±3.14 in the 60 ≤ age group, while in the Indian population 11.43 in the 30 ≤ age group. It was found as ± 3.28, 11.42 ± 3.00 in the 31–60 age group, and 10.64 ± 3.14 in the 60 ≤ age group. This comparison shows the DER differences between the Anatolian and Indian populations.
When the ulnar variance was evaluated according to age, the negative variance in the Anatolian population was 50% in the 17–29 age group, 40.3% in the 30–59 age group, and 16.5% in the 60 ≤ age group. Nekkanti et al. found a negative variance in their study 48.6% in the 30 ≤ age group in the Indian population, 36.9% in the 31–60 age group, and 19.2% in the 60 ≤ age group. In the Anatolian population, the positive variance was 37.5% in the 17–29 age group, 42% in the 30–59 age group, and 83.3% in the 60 ≤ age group, while the positive variance in the Indian population was 11.2% in the 30 ≤ age group, 11.4% in the 31–60 age group, and 15.4% in the 60 ≤ age group. In the Anatolian population, the neutral variance was 12.5% in the 17–29 age group, 17.7% in the 30–59 age group, while no neutral variance was found in the 60 ≤ age group. In the Indian population, the neutral variance was 40.2% in the 30 ≤ age group, 51.7% in the 31–60 age group, and 65.4% in the 60 ≤ age group. While the Anatolian population tended to have more negative ulnar variance, it was determined that the Indian population tended to have more neutral ulnar variance.
In treating distal radius fractures, surgeons use the current reference values of Gartland and Werley as standard (Gartland and Werley, 1951). However, the authors think morphometric parameters vary from country to country, race, ethnicity, and patient structure. Therefore, unawareness of this fact may be why orthopedists adopt the only available Western data of the morphometric parameters of the DER (Nekkanti et al., 2018). Chan et al. (2008) found that ulnar variance was statistically significant in the Chinese and Malaysian populations (Hadi and Wijiono, 2013; Chan et al., 2008). In this study, when the Anatolian population and other populations are compared, there is a difference in the DER values of the Anatolian population. As can be understood from the comparison in the table, the Anatolian population differs according to India, Malaysia, China, and other countries (Tables 6 and 7).
Distal radius morphometry is an essential factor in the clinical setting. Therefore, it is necessary to know the average values of the distal morphometry, as one of the goals of fracture management is to restore anatomical alignment. In addition, positive ulnar variance is considered one of the possible factors predisposing to Kienbock's disease (Chan et al., 2008). The earliest effect of fused distal radius fractures on the normal biomechanics of the wrist joint was described by Gartland and Werley in 1951 (Gartland and Werley 1951). Scoring systems have been widely used to evaluate the functional outcomes of the treatment of distal radius fractures. As a result of the clinical studies of DER conducted to date, the importance of restoring the normal alignment of the distal radius in the event of a fracture has been emphasized (Taleisnik and Watson, 1984; Altissimi et al. 1986; Porter and Stockley, 1987; Beumer and Lindau, 2014).
The limitation of our study was that the number of images in the appropriate position and the desired criteria was low since the study was retrospective. There were also images of one side, and no right-to-left comparisons were made. However, Mishra et al.,(2016) In their study, stated that they did not find a significant difference between the right and left arms.
As observed in our study, the standard parameters differ significantly from the Anatolian, West, and East Asian populations. Therefore, there is a need to examine each race and report normal radiological parameters of the distal radius.