No abstract

We report the recent occurrence of spontaneous humeral shaft fractures in 12 pitchers. The subjects were interviewed over the telephone using a standard questionnaire. Radiographs and medical records were solicited from their physicians. Their average age was 36 years and they had pitched an average of 11.4 years with an average layoff of 14 years (range, 7 to 24). Mean time between games pitched was 21 days (range, 3 to 56). The average number of pitches before the fracture occurred was 38 (range, 10 to 100). Pain was experienced at some point before the fracture in 75% of the pitchers and 75% of the fractures were spiral. These fractures were most probably spontaneous fractures brought on by accumulated fatigue damage. The period of buildup after a prolonged period of layoff was probably insufficient time for proper bone remodeling to occur in these men. While a large percentage of these men had pain before their injury, suggesting a predisposing stress fracture, there is no doubt that their fractures could still be caused by a sudden torsional load without the presence of a stress fracture.

The purpose of this study was to define the intraosseous and extraosseous blood supply of the hallucal sesamoids by studying a total of 10 fresh-frozen, below-knee specimens with no evidence of vascular disease. Most specimens were injected with high grade India ink, cleared using a standard Spalteholz technique, and processed to delineate the extraosseous and intraosseous blood supply to include soft tissue dissection and coronal sectioning. Two additional specimens were injected with blue Mercox acrylic solution to further define the extraosseous vasculature. The major extraosseous blood supply to the sesamoids is via the posterior tibial artery. This vessel then branches into the medial plantar artery which further divides upon entering the medial and lateral sesamoids in their proximal poles. Vessels in the peripheral soft tissues, although abundant, do not seem to penetrate the cortex of the sesamoids. The intraosseous blood supply to the sesamoids seems to be threefold. Mainly, sesamoid arteries enter the lateral and medial sesamoids from the proximal aspect via a single vessel. This proximal vessel proceeds distally with a network of branching. Plantar, nonarticular vessels enter the sesamoids, constituting a second source of vascularity. Finally, small vessels also enter the sesamoids through medial and lateral capsular attachments. Based on this study, a possible explanation for avascular necrosis and nonunion of sesamoids is proposed, and an optimal surgical approach is discussed.(ABSTRACT TRUNCATED AT 250 WORDS)