[The bare area of the proximal ulna : An anatomical study on optimizing olecranon osteotomy]. / Die Bare Area der proximalen Ulna : Eine anatomische Studie zur Optimierung der Olekranonosteotomie.

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. OBJECTIVES: 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. MATERIALS AND METHODS: The bare areas of 30 embalmed forearm specimens were marked with a radiopaque wire and visualized three-dimensionally with a mobile C­arm. 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.

The course of the posterior interosseous nerve in relation to the proximal radius: is there a reliable landmark?

PURPOSE: The posterior interosseous nerve (PIN) is closely related to the proximal radius, and it is at risk when approaching the proximal forearm from the ventral and lateral side. This anatomic study analyzes the location of the PIN in relation to the proximal radius depending on forearm rotation by means of a novel investigation design. The purpose of this study is to define landmarks to locate the PIN intraoperatively in order to avoid neurological complications. METHODS: We dissected six upper extremities of fresh-frozen cadaveric specimens. The mean donor age at the time of death was 81.2 years. The PIN was dissected and marked on its course along the proximal forearm with a 0.3-mm flexible radiopaque thread. Three-dimensional (3D) X-ray scans were performed, and the location of the nerve was analyzed in neutral rotation, supination, and pronation. RESULTS: In the coronal view, the PIN crosses the radial neck/shaft at a mean of 33.4 (±5.9)mm below the radial head surface (RHS) in pronation and 16.9 (±5.0)mm in supination. It crosses 4.9 (±2.2)mm distal of the most prominent point of the radial tuberosity (RT) in pronation and 9.6 (±5.2)mm proximal in supination. In the sagittal view, the PIN crosses the proximal radius 61.8 (±2.9)mm below the RHS in pronation and 41.1 (±3.6)mm in supination. The nerve crosses 29.2 (±6.2)mm distal of the RT in pronation and 11.0 (±2.8)mm in supination. CONCLUSION: With this novel design, the RT could be defined as a useful landmark for intraoperative orientation. On a ventral approach, the PIN courses 10mm proximal of it in supination and 5mm distal of it in pronation. Laterally, pronation increases the distance of the PIN to the RT to approximately 3cm.

Tax-exempt hospital financing: revenue bonds.

When a hospital must issue a tax-exempt bond, it can influence the net interest cost by instituting in advance both risk reduction methods and cash flow adequacy measures. Hospital managers should consider when initiating projects that will impact on cash flow and revenue as well as in creating the accompanying financing package.