[The bare area of the proximal ulna : An anatomical study on optimizing olecranon osteotomy].
BACKGROUND
Olecranon osteotomy is an established approach for the treatment of distal humerus fractures. It should be performed through the bare area of the proximal ulna to avoid iatrogenic cartilage lesions.


OBJECTIVE
The goal of this study was to analyze the anatomy of the proximal ulna with regard to the bare area and, thereby, to optimize the hitting area of the bare area when performing olecranon osteotomy.


METHODS
The bare areas of 30 embalmed forearm specimens were marked with a radiopaque wire and visualized three-dimensionally with a mobile C‑arm. By means of 3D reconstructions of the data sets, the following measurements were obtained: height of the bare area; span of the bare area-hitting area in transverse osteotomy; ideal angle for olecranon osteotomy to maximize the hitting area of the bare area; distance of the posterior olecranon tip to the entry point of the transverse osteotomy and the ideal osteotomy.


RESULTS
The height of the bare area was 4.92 ± 0.81 mm. The hitting area of the transverse osteotomy averaged 3.73 ± 0.89 mm. The "ideal" angle for olecranon osteotomy was 30.7° ± 4.19°. The distance of the posterior olecranon tip to the entry point was 14.08 ± 2.75 mm for the transverse osteotomy and 24.21 ± 3.15 mm for the ideal osteotomy. The hitting area of the bare area in the ideal osteotomy was enhanced significantly when compared to the transverse osteotomy (p < 0.0001).


CONCLUSIONS
This study provides guide values for correct osteotomy of the olecranon. Moreover, a 30° angulation of the osteotomy can significantly increase the hitting area of the bare area.
Institut I für Anatomie, Universität zu Köln, Köln, Deutschland. michael.hackl@uk-koeln.de.|Schwerpunkt für Unfall-, Hand- und Ellenbogenchirurgie, Universitätsklinik zu Köln, Kerpener Straße 62, 50937, Köln, Deutschland. michael.hackl@uk-koeln.de.|Cologne Center for Musculoskeletal Biomechanics (CCMB), Universität zu Köln, Köln, Deutschland. michael.hackl@uk-koeln.de.
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M
Hackl
Schwerpunkt für Unfall-, Hand- und Ellenbogenchirurgie, Universitätsklinik zu Köln, Kerpener Straße 62, 50937, Köln, Deutschland.|Cologne Center for Musculoskeletal Biomechanics (CCMB), Universität zu Köln, Köln, Deutschland.
S
S
Lappen
Institut I für Anatomie, Universität zu Köln, Köln, Deutschland.
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WF
Neiss
Institut II für Anatomie, Universität zu Köln, Köln, Deutschland.
M
M
Scaal
Schwerpunkt für Unfall-, Hand- und Ellenbogenchirurgie, Universitätsklinik zu Köln, Kerpener Straße 62, 50937, Köln, Deutschland.|Cologne Center for Musculoskeletal Biomechanics (CCMB), Universität zu Köln, Köln, Deutschland.
L P
LP
Müller
Schwerpunkt für Unfall-, Hand- und Ellenbogenchirurgie, Universitätsklinik zu Köln, Kerpener Straße 62, 50937, Köln, Deutschland.|Cologne Center for Musculoskeletal Biomechanics (CCMB), Universität zu Köln, Köln, Deutschland.
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K
Wegmann
D002102:Cadaver; D004551:Elbow Joint / Q000033:anatomy & histology* / Q000601:surgery*; D006801:Humans; D008953:Models, Anatomic; D056740:Olecranon Process / Q000033:anatomy & histology* / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
Arm; Cartilage; Elbow joint; Olecranon; Osteotomy