They are composed of irregular, anastomosing and longitudinal cylinders formed from concentric lamellae. This longitudinal orientation explains why long bones resist coaxial forces much better than perpendicular forces. Haversian canals form the central conduit of the osteon. These canals are connected to one another via canaliculi. Cement lines define and separate each individual osteonal complex. Canaliculi and collagen fibrils will not cross cement lines. For this reason, cracks will follow cement lines rather than cross osteons. In Conclusion When treating the diabetic patient for either trauma or for elective reconstruction, one must take into account the various factors that may impede normal bone healing. These factors may include poor long-term blood glucose control, poor nutritional status, poor vascularity and long-term osteodystrophy. In order to balance these deleterious factors, one should consider utilizing more aggressive fixation constructs, surgical strategies that yield little soft tissue compromise, tuning up nutritional factors and incorporating modern orthobiologic materials and techniques. Dr. Weinraub is a Fellow of the American College of Foot and Ankle Surgeons. He is a Clinical Assistant Professor of Medicine at the University of Virginia and a Clinical Assistant Professor of Orthopaedic and Podiatric Surgery at the Virginia College of Osteopathic Medicine. Dr. Weinraub can be contacted at firstname.lastname@example.org. Dr. Steinberg (pictured) is an Assistant Professor in the Department of Surgery at the Georgetown University School of Medicine in Washington, D.C. He is a Fellow of the American College of Foot and Ankle Surgeons.
References 1. Perren SM. Physical and biological aspects of fracture healing with special reference to internal fixation. Clin Orthopaedics and Related Research. 138: 175-195, 1979. 2. Macey LR, Kana SM, Jingushi S, Terek RM, Borretos J, Bolander ME. Defects of early fracture healing in experimental diabetes. J Bone Joint Surg Am, 71 (5), 722-733, 1989. 3. Funk JR, Hale JE, Carmines D, Gooch HL, Hurwitz SR. Biomechanical evaluation of early fracture healing in normal and diabetic rats. J Orthop Res. 18 (1), 126-132, 2000. 4. Boddenberg U. Healing time of foot and ankle fractures in patients with diabetes mellitus: literature review and report of own cases. Zentralbl Chir. 129 (6), 453-459, 2004. 5. Kloting N, Follak N, Kloting I. Is there an autoimmune process in bone? Gene expression studies in diabetic and nondiabetic BB rats as well as BB rat related and unrelated rat strains. Physiol Genomics, 24 (1), 59-64, 2005. Additional References 6. Boskey AL. Mineral matrix interactions in bone and cartilage. Clin Orthop, 281: 244-274, 1992. 7. Buckwalter JA, Glimcher MJ, Cooper RR, Recker R. Bone Biology. J Bone Joint Surg, 77A (8), 1276-1289, 1995.