Ischaemia, healing and outcomes in proximal humeral fractures

Abstract

Interfragmental ischaemia is a prerequisite for the initiation of the inflammatory and immunological response to fracturing of bone.Intrafragmental ischaemia is inevitable: the extent of the initial ischaemic insult does not, however, directly relate to the outcome for healing of the fracture zones and avascular necrosis of the humeral head. The survival of distal regions of fragments with critical perfusion may be the result of a type of inosculation (blood vessel contact), which establishes reperfusion before either revascularization or neo-angiogenesis has occurred.Periosteum has a poorly defined role in fracture healing in the proximal humerus. The metaphyseal periosteal perfusion may have a profound effect, as yet undefined, on the healing of most metaphyseal fractures of the proximal humerus, and may be disturbed further by inadvertent surgical manipulation.The metaphysis can be considered as a ‘torus’ or ring of bone, its surface covered by periosteum antero- and posterolaterally, through which the tuberosity segments gain perfusion and capsular reflections antero- and posteromedially, through which the humeral head (articular) fragment gains perfusion.The torus is broken in relatively simple primary patterns: a fracture line at the upper surface of the torus is an anatomical ‘neck’ fracture; a fracture line at the lower surface of the torus is the surgical ‘neck’ fracture. Secondary fragmentation (through compression and/or distraction) of the torus itself creates complexity for analysis (classification), alters the capacity and outcome for healing (by variable interruption of the fragmental blood supply) and influences interfragmental stability.Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.180005

An anatomical investigation into the blood supply of the proximal humerus: surgical considerations for rotator cuff repair

“…Based on earlier research, branches from the anterior circumflex humeral artery (ACHA) are the main blood supply to the HH, 10 , 13 , 16 but other researchers suggested that the posterior circumflex humeral artery (PCHA) may also contribute more toward the vascularization of the proximal humerus 3 , 8 . Lambert 17 suggested that the PCHA is of more importance to articular segment and tuberosity perfusion than the ACHA. Regardless of the contribution of blood supply to the HH, both of these arteries' intraosseous components and networks are potentially at risk during anchor placement.…”

Biomechanical behavior of three types of fixation in the two-part proximal humerus fracture without medial cortical support

“…Chen et al observed that the average distances between the origin of the AHCA and the infraglenoid tubercle, the coracoid process, the acromion, and the mid-clavicular line were 26.9 mm, 49.2 mm, 67.0 mm, and 74.9 mm, respectively [17]. Anatomically, the medial, posterior-medial, and lateral regions are critical for the entry of the humeral circumflex artery branches, and should be avoided in placing retractors as well as implants [18]. Because the plate is positioned on the anteromedial face of the humeral head, there is less risk of intraoperative vascular damage.…”

“…Because the plate is positioned on the anteromedial face of the humeral head, there is less risk of intraoperative vascular damage. Additionally, Lambert showed that the head of the humerus can be completely revascularized, even when there is significant deviation or fragmentation of the posteromedial cortex, since significant anastomoses are distally present between the deltoid and ACHA [18]. As a result, at least four holes should be used for the medial plate, which should be located at the level of the insertion of the upper margin of the teres major muscle, just above the metaphyseal arterial ring.…”

Mathematical Modeling of the Stress-Strain State of the “Bone-Implant” System During the Osteosynthesis With a Philos With Polylactic Acid Implants

“…In other cases, open reposition and internal fixation of the PHF are prescribed, which may be ineffective due to osteoporosis. Despite the widespread clinical practice of new designs for osteosynthesis (plates with angular stability, blocked intramedullary rods, cannulated screws) and a number of publications, demonstrating the effectiveness of their application [7][8][9][10][11]. There is a high risk of avascular necrosis development in the head of humerus, nonunion of fragments, redislocation of fragments and metal migration which according to different authors can comprise up to 30 % [7][8][9][10][11][12].…”