Study Suggests Poor Blood Supply Not the Cause of Healing Problems in Scaphoid Fractures
A study presented today at the American Academy of Orthopaedic Surgeons (AAOS) 2018 Annual Meeting suggests that poor blood supply may not be the reason why certain bone fractures of the wrist do not heal properly, as previously thought. The findings also may help surgeons better plan surgical approaches to fracture repair while also identifying patients who will likely have a tougher go at recovery and require more follow up care.
The movement of our hands and wrists partially relies on a small, cashew-shaped bone called the scaphoid. The proximal pole of the bone — meaning the end abutting the arm rather than the hand — is notoriously slow to heal following a fracture and is prone to a condition called avascular necrosis, in which the bone tissue dies due to lack of blood supply.
It was previously thought that the poor healing was due to a unique and lacking vasculature at the bone’s proximal end. Yet the new study found that this area of the bone actually receives over 37 percent of the scaphoid’s entire blood supply, so it is actually as well-nourished as the other two regions of the bone. However, the very tip of the proximal pole did appear to have minimal vasculature perhaps explaining why it is prone to healing problems following a break.
"Our study suggests that the proximal pole of the scaphoid actually has a similar amount of internal blood supply as the rest of the scaphoid, not less as has traditionally been taught," says Duretti Fufa, MD, hand and upper extremity surgeon at Hospital for Special Surgery (HSS) in New York City and lead author of the new study. "If the amount of blood supply in the proximal pole of the scaphoid is not different from the rest of the scaphoid, then we need to think of alternative explanations for the poorer results of treatment in this area."
Dr. Fufa explains that the poor healing rates seen in proximal scaphoid break could be due to mechanical influences or injury pattern more so than simply blood supply.
The vasculature of the scaphoid was originally described decades ago and based on cadaver dissections. Dr. Fufa and her HSS colleagues who took part in the study also utilized cadaver analysis to achieve their results. However modern, high-resolution imaging technologies allowed them to better characterize the vessels that supply blood to the scaphoid.
To follow up the new study, Dr. Fufa and fellow HSS hand specialists are collaborating to review the break and healing patterns of hundreds of patients with broken scaphoid bones.
"Our goal is to see if we can determine alternate classification systems for describing scaphoid fractures that incorporates this new information and may better inform our treatment of these injuries," she says.