The influence of proximal ulnar morphology on elbow range of motion.
BACKGROUND
Physiologic dorsal apex angulation of the proximal ulna is present in 96% of the population. We hypothesize that a correlation exists between the physiologic dorsal ulnar angulation and elbow range of motion (ROM).


METHODS
Fifty healthy adults underwent bilateral lateral elbow radiographs in neutral forearm rotation in the following positions: terminal flexion (TF), 90° of flexion, and terminal extension (TE). The proximal ulna dorsal angulation (PUDA), TF, and TE were measured on the digital lateral radiographs by 2 independent observers. ROM was calculated as the difference between TF and TE measurements. Subjects were divided into 2 groups: those with PUDA measurements less than the median and those with PUDA measurements equal to or greater than the median. The relationship between the PUDA and TE, TF, and ROM was evaluated by use of Pearson correlation coefficients.


RESULTS
The mean age of the cohort was 31 ± 9 years, and there were 30 women among the 50 volunteers. The sample of 100 elbow radiographs had a mean TF of 150.8° ± 4.5°, a mean TE (ie, flexion contracture) of 11.5° ± 7.3°, and a mean ROM of 139.3° ± 8.4°. The mean PUDA was 5.2° ± 2.8°. Elbows with a greater PUDA had significantly less TE (r = 0.381, P ≤ .001) and ROM (r = -0.351, P ≤ .001). The group of elbows with a lesser PUDA had better TE (9.4° vs 13.6°, P = .004) and ROM (142.0° vs 136.7°, P = .001) than elbows with a greater PUDA.


CONCLUSIONS
The increasing magnitude of the PUDA is associated with decreased maximal elbow extension and global elbow ROM.
Recherche Orthopedie C2095, Hôpital du Sacré-Cœur, Montréal, Québec, Canada. dominique_rouleau@yahoo.ca
Dominique M
DM
Rouleau
Fanny
F
Canet
Julien
J
Chapleau
Yvan
Y
Petit
Emilie
E
Sandman
Kenneth J
KJ
Faber
George S
GS
Athwal
D000328:Adult; D015331:Cohort Studies; D004551:Elbow Joint / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D012016:Reference Values; D012399:Rotation; D014457:Ulna / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*