Functional outcome one year after osteoporotic vertebral compression fractures

Osteoporosis is one of the ten most common diseases worldwide. In 2007, more
than 142.000 people in the Netherlands were diagnosed with osteoporosis.
Moreover, based on demographic data as population growth and increase in
ageing, an increase of 38% is estimated in 2025. The most common sequelae of
osteoporosis are vertebral compression fractures with approximately half of all
osteoporotic fractures annually in the USA. Even more, the actual incidence of
vertebral fractures is said to be highly underestimated given the large number
of fractures of the vertebrae that is never clinically diagnosed. The World
Health Organisation (WHO) defines osteoporosis as a T-score (standard deviation
[SD] score related to mean bone mineral density (BMD) of young [20-29 years]
normal Caucasian women) equal to, or below, -2.5. BMD is measured by dual X-ray
absorptiometry (DXA), which is the current gold standard for diagnosing
osteoporosis because of its low cost, low radiation and ease of use. However,
limitations of DXA in assessing bone strength and the corresponding fracture
risk are more and more recognised. The accuracy to predict fracture risk is
said to increase with site-specific measurements. Volumetric BMD (vBMD) can be
measured non-invasively by quantitative computed tomography (QCT). Finite
element analysis estimates vertebral strength for a simulated compression
over-load. To evaluate 3D bone geometry, QCT has been found to be more
sensitive than DXA. Vertebral fractures are strongly correlated with increasing
age, which is associated with decreasing bone density. Francis et al. stated
that the risk of developing a vertebral fracture is increasing more than two
times for every standard deviation below average vertebral BMD. Besides age,
other factors as genetic predisposition and lifestyle choices like smoking and
excessive alcohol intake increase the risk of osteoporosis. Furthermore, the
risk of developing an adjacent vertebral fracture within a year of an initial
vertebral fracture in osteoporotic patients is 20%.
Numerous studies have been published about the optimal treatment of a
osteoporotic vertebral compression fracture. In the scientific literature, a
controversial discussion is ongoing whether to treat conservatively or
surgically and when a surgical intervention is indicated, which procedure
should be performed. Conservative treatment, consisting of painkillers such as
NSAIDs (non-steroidal anti-inflammatory drugs) and relatively immobilization
with physical therapy, can help relieve the pain during the healing process.
Also, bracing is commonly used for symptomatic management. There is, however,
little evidence on its application for osteoporotic compression fractures.
Ability to perform activities in daily living (ADL) and quality in life may
increase in some cases, but patient discomfort such as skin breakdown and
respiratory volume restriction is reported frequently too. As such, many
authors have moved away from recommending rigid braces. Prescription of
anti-resorptive osteoporosis medications can increase BMD and therefore reduce
the risk of a additional fracture. Although, low success rates are found by
Maeda et al. by non-compliance due to adverse side effects, such as nausea.
As well as conservative treatment, surgical intervention is mostly aimed at
pain relief but is intended to improve functional outcome too. In some cases an
absolute indication for surgical intervention is recognised. These include
compression of the spinal cord or cauda equine which results in loss of
sensation and/or weakness in the lower extremities. In these cases an emergency
surgery may constitute. In other cases, when an initial conservative therapy
does not adequately relieve the pain, surgical intervention should be
considered. Approximately one-third of osteoporotic vertebral compression
fractures does not heal with conservative treatment. The loss of height
resulting from the fracture may result in a resultant kyphotic deformity or
decreased lumbar lordosis, which can be progressive in cases of delayed or
non-union. This collapse may shift the plumb line of C7 ventrally. Sagittal
imbalance occurs as this plumb line passes in front of the femoral heads. Even
after the fracture is healed, this may lead to chronic back pain and associated
fatigue due to actively increasing lumbar lordosis as initial compensation. If
additional extension of the lumbar spine is not possible, tilting the pelvis
backwards adds further compensation. Flexing the knee joints is the last step
in compensating an imbalance situation of the spine. This compensation
mechanism can be seen on full spine X-rays (C1 to pelvis including the hips and
femur heads) and measured by standard pelvic parameters such as pelvic
incidence (PI), pelvic tilt (PT) and sacral slope (SS). This method is called
*full balance integrated* (FBI) and is widely studied by le Huec et al. to
assess the balance of the spine. Sagittal imbalance can limit a patient*s
quality of life and ADL severely. Another important issue of quality of life is
physical activity. With the aging process, besides a decrease in bone density,
skeletal muscle mass and strength is decreased as well. (Doherty, 2003) For
conservation of musculoskeletal health, physical activity is recommended as an
effective intervention. (Maltais, 2009) Accelerometer-based measurement of
movement is an accepted method for monitoring physical activity (Mathie, 2004).
Association of loading of physical activity and bone and muscle strength is
studied by Chahal with accelerometric methods (2014). However, little is known
about the association with quality of life.
Fracture patterns in osteoporotic compression fractures have been studied by
Genant et al. This method assesses the severity of vertebral fractures by
visual determination of the extent of vertebral height reduction and
morphological change, and vertebral fractures are differentiated from other,
non-fracture deformities. This makes the classification suitable for clinical
application.
Aim of this observational cohort-study is to evaluate the functional outcome of
patients with an osteoporotic vertebral compression fracture and its
correlation with deterioration of sagittal alignment, severity of osteoporosis
and type of fracture and rate of delayed or non-union. Our hypothesis is that
poorer functional outcome and delayed or non-union correlates with poor
sagittal alignment at inclusion, severe osteoporosis and high Genant
classification (Grade 2-3).

Primary objective:
1. To assess functional outcome of patients with an osteoporotic vertebral
compression fractures after one year of follow-up.
Secondary objectives:
1. To assess radiological deterioration of sagittal alignment during one year
of follow-up
2. To assess the effect of osteoporosis on deteriorated sagittal alignment
3. To assess the effect of the type of fracture on deteriorated sagittal
alignment
4. To assess the rate of non-union in relation to osteoporosis and type of
fracture
5. To assess the effect of physical activity on quality of life in patients
with an osteoporotic vertebral compression fracture.

A prospective, single centre, observational study. Patients will be monitored
during a period of one year. Follow-up will take place at one week, three, six
and 12 months after inclusion.

Participation in this study doesn't influence the regular treatment. However,
there will be extra radiation because of extra diagnostic test, such as a
CT-scan at inclusion, full spine X-rays instead of X-rays of the thoracic resp.
lumbar spine. A bone scintigraphy will be done at 3 months for all subjects.
Subjects will be wearing an Accelerometer to measure their physical activity
twice for one week. Subjects receive this meter at their visit in the hospital
and can return it by mail.