Metaversion can reliably predict humeral head version: a computed tomography-based validation study.
OBJECTIVE
Circumstances occur when the determination of anatomic humeral head version is difficult. In the setting of irreparable proximal humeral fracture, there are few reliable intraoperative landmarks to determine anatomic humeral head version. This study tested our hypothesis that the metaphyseal version (metaversion) is a landmark that can assist with correct head version and used computed tomography (CT) to evaluate its reliability as a predictor of anatomic version.


METHODS
CT scans from 50 consecutive patients (20 women, 30 men) were examined using commercial software. Patients were a mean age of 46 years (range, 17-85 years). Exclusion criteria included previous fracture, arthritis, or humeral deformity. The metaversion and humeral head version were measured. Measurements were conducted independently by 2 surgeons blinded to the results of the other. Interobserver and intraobserver reliability was calculated using intraclass correlation.


RESULTS
The mean difference between the metaversion and the humeral head version was 2.5° (95% confidence interval [CI], 0.9°-3.9°). The mean difference between metaversion and humeral head version was 1.8° (95% CI, 0.0°-3.6°) in women, 2.9° (95% CI, 0.6°-5.1°) in men, 2.4° (95% CI: 0.6°-4.1°) in right shoulders, and 2.5° (95% CI, -0.1° to 5.1°) in left shoulders. Interrater and intrarater reliability was excellent, 0.97 and 0.98, respectively.


CONCLUSIONS
Proximal humeral metaphyseal version (metaversion) is an accurate predictor of ipsilateral humeral head version.
Athwal
George S
GS
Division of Orthopedic Surgery, University of Western Ontario, Hand and Upper Limb Centre, London, Ontario, Canada. gathwal@uwo.ca
MacDermid
Joy C
JC
Goel
Danny P
DP
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D058430:Humeral Head / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D014057:Tomography, X-Ray Computed