Injury | International Journal of the Care of the Injured - Volume 47 - Supplement 2 - June 2016

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Failure of fracture fixation in osteoporotic bone
Christian von Rüdena,b, Peter Augata,b,*
aInstitute of Biomechanics, Berufsgenossenschaftliche Unfallklinik Murnau, Germany
bInstitute of Biomechanics, Paracelsus Medical University Salzburg, Austria
A B S T R A C T
This manuscript will provide an overview of how the age and osteoporosis related changes in mechanical
properties of bone affect the stability of osteosynthesis constructs, both from a mechanical as well as from a
clinical perspective. The manuscript will also address some of the principles of fracture fixation for osteoporotic
fractures and discuss applications of osteoporotic fracture fixation at sites typically affected by fragility fractures,
namely the distal radius, the proximal humerus, the femur and the spine. The primary aim of operative treatment
in elderly individuals is the avoidance of immobilization of the patient. In selected cases conservative treatment
might be required. Generally, choice of treatment should be individualized and based on the evaluation of patient-
specific, fracture-specific and surgeon-specific aspects. The orthopaedic surgeon plays an essential role in
enabling functional recovery by providing good surgery but a multidisciplinary approach is essential in order to
support the patient to regain his/her quality of life after fragility fracture. Overall, the therapy of fractures in
osteoporotic bone in the elderly requires a multidisciplinary therapeutic acute care concept including treatment of
co-morbidities and correct choice of timing, and technique of the operative intervention.
© 2016 Elsevier Ltd. All rights reserved.
K E Y W O R D S
Biomechanics
Osteosynthesis
Fragility Fractures
Fracture treatment
Femur
Humerus
Spine
Radius
Introduction
In an aging population the number of fractures seen in orthopedic
institutions steadily increases. The treatment and care of these elderly
patients constitutes a challenge for the individual orthopedic surgeon,
the hospital staff and the health care systems worldwide. Many of these
challenges are related to the age of the patient and the frequency of
comorbidities. Therefore, the successful treatment of the fracture with
fast recovery of the mobility is essential for the patient’s survival and
wellbeing. A reasonable return to function and a successful healing in
the elderly requires a mechanical stable internal fixation and rapid
rehabilitation. Elderly individuals will not be able to adhere to partial
weight-bearing protocols and thus require osteosynthesis which
tolerates full weight-bearing. Thus the need for stable internal fixation
in osteoporotic bone is paramount. The hardware for fracture fixation is
typically designed to maintain its stability during full weight bearing.
However, the bone in elderly individuals often lacks mechanical
strength for stable anchorage of plates, screws or nails. Age related
degradation of bone and the additional bone weakening through age
related diseases such as osteoporosis reduce the ability of bone to
withstand increased loading. Often the bone around screws and nails
fails prematurely and leads to subsidence, cut through or cut out of
metal hardware and ultimately to failure of fracture fixation [1]. This
manuscript will provide an overview of how the age and osteoporosis
related changes in mechanical properties of bone affect the stability
of osteosynthesis constructs, both from a mechanical as well as from
a clinical perspective. Principles of fracture fixation for osteoporotic
fractures will also be discussed. However, it should be recognized that
fragility fractures require a multidisciplinary management of the acute
fracture episode and ongoing activities to prevent secondary fractures
[2]. The orthopaedic surgeon plays an essential role in enabling
functional recovery by providing good surgery but a multidisciplinary
approach is essential for the fracture patient to regain his quality of life.
Mechanical properties of bone in osteoporosis
The ability of bone to resist fracture and withstand loads depends
on the amount of bone (bone mass), its distribution in space and the
intrinsic material properties of the bone tissue [3]. Using engineering
principles these factors can be used to predict failure load of a given
bone with fairly high accuracy [4,5]. However, the failure load for a
bone with certain strength will strongly depend on the loading mode.
A proximal femur will fracture at considerably lower loads if the
loading mode is a sideways fall on the greater trochanter as compared
to loading applied to the femoral head in a stance configuration [5].
* Corresponding author at: Institute of Biomechanics, Berufsgenossenschaftliche
Unfallklinik, Murnau Prof.-Kuentscher-Str. 8, D-82418 Murnau am Staffelsee, Germany.
Tel.:+49 8841 484563; fax:+49 8841 484573.
E-mail address: (P. Augat).
Injury, Int. J. Care Injured 47S2 (2016) S3–S10
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0020-1383 / © 2016 Elsevier Ltd. All rights reserved.