Late lower extremity fractures in patients with paraplegia

Rehabilitation Towards Functional Independence in a Patient With Intertrochanteric Fracture and Paraplegia: A Case Report

Traumatic spinal cord injury (SCI) causes significant neurological deficits that adversely affect the quality of life of patients and caregivers. Patients with SCI present with the symptoms of weakness and loss of sensations in the limbs. Motor deficits may occur in the form of paraplegia, hemiplegia, or quadriplegia. Patients remain immobilized for a prolonged period which may lead to complications like muscle wasting, atrophy, joint stiffness, contractures, bed sores, and osteoporosis. Patients are prone to fractures owing to osteoporosis. The fractures may occur even due to trivial trauma. Our case report presents the case of a 45-year-old male patient who is already diagnosed with paraplegia having a history of SCI one-and-a-half years ago. He has recent history of intertrochanteric (IT) fracture that occurs during the transfer from bed to wheelchair. Admitted to the hospital with a complaint of a popping sound along with low back pain. Further investigation and management were started.

Pharmacological approaches for bone health in persons with spinal cord injury

Spinal cord injury (SCI) results in rapid, marked skeletal deterioration below the level of neurological lesion. Ideally, the most effective therapeutic approach would prevent loss of bone mass and architecture shortly after paralysis. Bisphosphonates preserve bone mineral density at the hip but not at the knee, which is the anatomical site most prone to fracture in the SCI population. Denosumab has recently been reported to prevent bone loss in persons with acute SCI but should be continued for an as yet indeterminate time because discontinuation will result in rapid bone loss. Several other novel approaches to preserving bone at the time of acute SCI should be tested, as well as approaches to reverse bone loss in individuals with chronic SCI.

Mortality after distal femur fractures in the elderly

INTRODUCTION

the frequency of distal femur fractures in the elderly is rapidly increasing. A study of these fractures was conducted in our center in order to evaluate the comorbidities and the mortality associated with this entity.

MATERIAL AND METHODS

all the distal femur fractures by low energy in patients over 65 years old at a tertiary center were included, between January 2010 and December 2016. Baseline characteristics, the type of fracture, comorbidities, and functional status before admission, were collected. The relationship of each of these variables to the final functional class, immediate and late complications and mortality during the follow-up. Fifty-nine patients were included, with a median age of 85.3 years (IQR 78.6-91.6). Fifty-one patients were women. In 10 patients, the fractures were atraumatic (postural change mainly in non-walking patients), and in 54 of the cases were treated surgically (6 with retrograde intramedullary nailing and 48 with lateral locking plate). The median time to surgery was 4.5 days (IQR 2-6) and 14 patients were operated within 48 hours. The median follow-up was 26.3 months.

RESULTS

fourteen patients died during the first year of follow-up. Factors independently associated with death during the first year after the fracture were: conservative treatment, and the inability to ambulate before the episode. The absence of certain comorbidities, such as chronic heart disease, and cancer, and an age under 80 years, behaved as protective factors.

CONCLUSION

low-energy distal femur fractures comprise a severe injury in the elderly and are associated with high mortality. Surgical treatment showed better outcomes in terms of survival, with no significant differences depending on the type of fracture, the type of implant or the median time to surgery.

Stiffness and Strength Predictions From Finite Element Models of the Knee are Associated with Lower-Limb Fractures After Spinal Cord Injury

Spinal cord injury (SCI) is associated with bone fragility and fractures around the knee. The purpose of this investigation was to validate a computed tomography (CT) based finite element (FE) model of the proximal tibia and distal femur under biaxial loading, and to retrospectively quantify the relationship between model predictions and fracture incidence. Twenty-six cadaveric tibiae and femora (n = 13 each) were loaded to 300 N of compression, then internally rotated until failure. FE predictions of torsional stiffness (K) and strength (T_ult) explained 74% (n = 26) and 93% (n = 7) of the variation in experimental measurements, respectively. Univariate analysis and logistic regression were subsequently used to determine if FE predictions and radiographic measurements from CT and dual energy X-ray absorptiometry (DXA) were associated with prevalent lower-limb fracture in 50 individuals with SCI (n = 14 fractures). FE and CT measures, but not DXA, were lower in individuals with fracture. FE predictions of T_ult at the tibia demonstrated the highest odds ratio (4.98; p = 0.006) and receiver operating characteristic (0.84; p = 0.008) but did not significantly outperform other metrics. In conclusion, CT-based FE model predictions were associated with prevalent fracture risk after SCI; this technique could be a powerful tool in future clinical research.

Surgical management of lower limb fractures in patients with spinal cord injury less associated with complications than non-operative management: A retrospective series of cases

OBJECTIVES

To evaluate the difference in terms of overall complications between surgical and non-surgical management of lower limb fractures in patients with chronic spinal cord injury (SCI).

DESIGN

A 13-year retrospective study including patients with chronic spinal cord lesion admitted for sublesional lower limb fractures.

SETTING

University hospital SCI reference departments (Rehabilitation department and orthopedic department).

PARTICIPANTS

Forty patients with SCI were included, 24 men and 16 women. Fifty-six distinct fracture occurrences were responsible for a total of 59 lower limb fractures. We compared the number of overall complications between surgical and non-surgical management of fractures.

RESULTS

Non-surgical management was realized for 19 fractures and surgery for 40. Characteristics of operated and non-operated patients at the time of each fracture occurrence did not differ concerning age (P = 0.430), sex (P = 0.890), lesion levels (P = 0.410) and AIS classification (P = 0.790). Data analysis highlighted 20 complications directly due to the fracture site for 16 distinct fractures. Seven medical complications were found in 5 distinct fracture events. Only 10 (25.0%) of 40 surgical managements had at least one medical or post-surgical complication, whereas 12 (63.2%) of 19 non-operative managements had at least one complication. Therefore, the overall rate of complications was significantly higher after non-surgical treatment (P = 0.044).

CONCLUSION

Lower extremity fractures due to osteoporosis in patients with SCI are responsible for local and general complications. When possible, surgery may be the best management to propose because of fewer overall complications.

Bone fragility after spinal cord injury: reductions in stiffness and bone mineral at the distal femur and proximal tibia as a function of time

Computed tomography and finite element modeling were used to assess bone structure at the knee as a function of time after spinal cord injury. Analyzed regions experienced degradation in stiffness, mineral density, and content. Changes were well described as an exponential decay over time, reaching a steady state 3.5 years after injury.

INTRODUCTION

Spinal cord injury (SCI) is associated with bone fragility and an increased risk of fracture around the knee. The purpose of this study was to investigate bone stiffness and mineral content at the distal femur and proximal tibia, using finite element (FE) and computed tomography (CT) measures. A cross-sectional design was used to compare differences between non-ambulatory individuals with SCI as a function of time after injury (0-50 years).

METHODS

CT scans of the knee were obtained from 101 individuals who experienced an SCI 30 days to 50 years prior to participation. Subject-specific FE models were used to estimate stiffness under axial compression and torsional loading, and CT data was analyzed to assess volumetric bone mineral density (vBMD) and bone mineral content (BMC) for integral, cortical, and trabecular compartments of the epiphyseal, metaphyseal, and diaphyseal regions of the distal femur and proximal tibia.

RESULTS

Bone degradation was well described as an exponential decay over time (R² = 0.33-0.83), reaching steady-state levels within 3.6 years of SCI. Individuals at a steady state had 40 to 85% lower FE-derived bone stiffness and robust decreases in CT mineral measures, compared to individuals who were recently injured (t ≤ 47 days). Temporal and spatial patterns of bone loss were similar between the distal femur and proximal tibia.

CONCLUSIONS

After SCI, individuals experienced rapid and profound reductions in bone stiffness and bone mineral at the knee. FE models predicted similar reductions to axial and torsional stiffness, suggesting that both failure modes may be clinically relevant. Importantly, CT-derived measures of bone mineral alone underpredicted the impacts of SCI, compared to FE-derived measures of stiffness.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01225055, NCT02325414).

The biology of fracture healing in osteoporosis and in the presence of anti-osteoporotic drugs

Compromised bone strength in osteoporosis predisposes patients to an increased fracture risk. The management of these fractures is complicated due to the poor bone quality, which may lead to inadequate fixation strength and stability. While a number of studies using osteoporotic animal models have shown a detrimental impact on fracture healing, clinical evidence regarding whether fracture healing is impaired in the presence of osteoporosis is complicated by numerous associated conditions including advancing age. The mechanism of some anti-osteoporotic medications creates concern about a potential detrimental impact on fracture healing, while others appear to enhance fracture healing. The current evidence indicates that the beneficial effects of anti-osteoporosis treatment exceeds any concerns about possible adverse consequences on fracture healing in most circumstances.

Bone loss at the distal femur and proximal tibia in persons with spinal cord injury: imaging approaches, risk of fracture, and potential treatment options

Persons with spinal cord injury (SCI) undergo immediate unloading of the skeleton and, as a result, have severe bone loss below the level of lesion associated with increased risk of long-bone fractures. The pattern of bone loss in individuals with SCI differs from other forms of secondary osteoporosis because the skeleton above the level of lesion remains unaffected, while marked bone loss occurs in the regions of neurological impairment. Striking demineralization of the trabecular epiphyses of the distal femur (supracondylar) and proximal tibia occurs, with the knee region being highly vulnerable to fracture because many accidents occur while sitting in a wheelchair, making the knee region the first point of contact to any applied force. To quantify bone mineral density (BMD) at the knee, dual energy x-ray absorptiometry (DXA) and/or computed tomography (CT) bone densitometry are routinely employed in the clinical and research settings. A detailed review of imaging methods to acquire and quantify BMD at the distal femur and proximal tibia has not been performed to date but, if available, would serve as a reference for clinicians and researchers. This article will discuss the risk of fracture at the knee in persons with SCI, imaging methods to acquire and quantify BMD at the distal femur and proximal tibia, and treatment options available for prophylaxis against or reversal of osteoporosis in individuals with SCI.

Should lower limb fractures be treated surgically in patients with chronic spinal injuries? Experience in a reference centre

OBJECTIVE

To report the outcomes of surgical treatment of lower limb fractures in patients with chronic spinal cord injuries.

MATERIAL AND METHOD

A total of 37 lower limb fractures were treated from 2003 to 2010, of which 25 fractures were treated surgically and 12 orthopaedically.

RESULTS

Patients of the surgical group had better clinical results, range of motion, bone consolidation, and less pressure ulcers and radiological misalignment. No differences were detected between groups in terms of pain, hospital stay, and medical complications.

DISCUSSION

There is no currently consensus regarding the management of lower limb fractures in patients with chronic spinal cord injuries, but the trend has been conservative treatment due to the high rate of complications in surgical treatment.

CONCLUSIONS

Chronic spinal cord injuries patients with lower limb fractures who are treated surgically achieved a more reliable consolidation, practically a free range of motion, low rate of cutaneous complications, and pain associated with the fracture. This allows a quick return to the previous standard of living, and should be considered as an alternative to orthopaedic treatment in these patients.

Bone Imaging and Fracture Risk after Spinal Cord Injury

Spinal cord injury (SCI) is characterized by marked bone loss and an increased risk of fracture with high complication rate. Recent research based on advanced imaging analysis, including quantitative computed tomography (QCT) and patient-specific finite element (FE) modeling, has provided new and important insights into the magnitude and temporal pattern of bone loss, as well as the associated changes to bone structure and strength, following SCI. This work has illustrated the importance of early therapeutic treatment to prevent bone loss after SCI and may someday serve as the basis for a clinical fracture risk assessment tool for the SCI population. This review provides an update on the epidemiology of fracture after SCI and discusses new findings and significant developments related to bone loss and fracture risk assessment in the SCI population based on QCT analysis and patient-specific FE modeling.

Reduction in Torsional Stiffness and Strength at the Proximal Tibia as a Function of Time Since Spinal Cord Injury

Spinal cord injury (SCI) is characterized by marked bone loss and a high rate of low-energy fracture around regions of the knee. Changes in the mechanical integrity of bone after SCI are poorly defined, and a better understanding may inform approaches to prevent fractures. The purpose of this study was to quantify reductions in torsional stiffness and strength at the proximal tibia as a function of time since SCI. Sixty adults with SCI ranging from 0 to 50 years of duration and a reference group of 10 able-bodied controls received a CT scan of the proximal tibia. Measures of integral bone mineral were calculated for the total proximal tibia, and localized measures of cortical and trabecular bone mineral were calculated for the epiphysis, metaphysis, and diaphysis. Torsional stiffness (K) and strength (T(ult)) for the total proximal tibia were quantified using validated subject-specific finite element models. Total proximal tibia measures of integral bone mineral, K, and T(ult) decreased exponentially (r(2)  = 0.52 to 0.70) and reached a new steady state within 2.1 to 2.7 years after SCI. Whereas new steady-state values for integral bone mineral and K were 52% to 56% (p < 0.001) lower than the reference group, the new steady state for T(ult) was 69% (p < 0.001) lower than the reference group. Reductions in total proximal tibia measures occurred through a combination of trabecular and endocortical resorption, leaving a bone comprised primarily of marrow fat rather than hydroxyapatite. These findings illustrate that a short therapeutic window exists early (ie, 2 years) after SCI, during which bone-specific intervention may attenuate reductions in mechanical integrity and ultimately prevent SCI-related fragility fracture.

Osteoporosis in individuals with spinal cord injury

The pathophysiology, clinical considerations, and relevant experimental findings with regard to osteoporosis in individuals with spinal cord injury (SCI) will be discussed. The bone loss that occurs acutely after more neurologically motor complete SCI is unique for its sublesional skeletal distribution and rate, at certain skeletal sites approaching 1% of bone mineral density per week, and its resistance to currently available treatments. The areas of high bone loss include the distal femur, proximal tibia, and more distal boney sites. Evidence from a study performed in monozygotic twins discordant for SCI indicates that sublesional bone loss in the twin with SCI increases for several decades, strongly suggesting that the heightened net bone loss after SCI may persist for an extended period of time. The increased frequency of fragility fracture after paralysis will be discussed, and a few risk factors for such fractures after SCI will be examined. Because vitamin D deficiency, regardless of disability, is a relevant consideration for bone health, as well as an easily reversible condition, the increased prevalence of and treatment target values for vitamin D in this deficiency state in the SCI population will be reviewed. Pharmacological and mechanical approaches to preserving bone integrity in persons with acute and chronic SCI will be reviewed, with emphasis placed on efficacy and practicality. Emerging osteoanabolic agents that improve functioning of WNT/β-catenin signaling after paralysis will be introduced as therapeutic interventions that may hold promise.

The mechanical consequence of actual bone loss and simulated bone recovery in acute spinal cord injury

INTRODUCTION

Spinal cord injury (SCI) is characterized by rapid bone loss and an increased risk of fragility fracture around regions of the knee. Our purpose was to quantify changes in torsional stiffness K and strength Tult at the proximal tibia due to actual bone loss and simulated bone recovery in acute SCI.

METHODS

Computed tomography scans were acquired on ten subjects with acute SCI at serial time points separated by a mean of 3.9months (range 3.0 to 4.8months). Reductions in bone mineral were quantified and a validated subject-specific finite element modeling procedure was used to predict changes in K and Tult. The modeling procedure was subsequently used to examine the effect of simulated hypothetical treatments, in which bone mineral of the proximal tibiae were restored to baseline levels, while all other parameters were held constant.

RESULTS

During the acute period of SCI, subjects lost 8.3±4.9% (p<0.001) of their bone mineral density (BMD). Reductions in K (-9.9±6.5%; p=0.002) were similar in magnitude to reductions in BMD, however reductions in Tult (-15.8±13.8%; p=0.005) were some 2 times greater than the reductions in BMD. Owing to structural changes in geometry and mineral distribution, Tult was not necessarily recovered when bone mineral was restored to baseline, but was dependent upon the degree of bone loss prior to hypothetical treatments (r≥0.719; p≤0.019).

CONCLUSIONS

Therapeutic interventions to halt or attenuate bone loss associated with SCI should be implemented soon after injury in an attempt to preserve mechanical integrity and prevent fracture.

Torsional stiffness and strength of the proximal tibia are better predicted by finite element models than DXA or QCT

Individuals with spinal cord injury experience a rapid loss of bone mineral below the neurological lesion. The clinical consequence of this bone loss is a high rate of fracture around regions of the knee. The ability to predict the mechanical competence of bones at this location may serve as an important clinical tool to assess fracture risk in the spinal cord injury population. The purpose of this study was to develop, and statistically compare, non-invasive methods to predict torsional stiffness (K) and strength (Tult) of the proximal tibia. Twenty-two human tibiae were assigned to either a "training set" or a "test set" (11 specimens each) and mechanically loaded to failure. The training set was used to develop subject-specific finite element (FE) models, and statistical models based on dual energy x-ray absorptiometry (DXA) and quantitative computed tomography (QCT), to predict K and Tult; the test set was used for cross-validation. Mechanical testing produced clinically relevant spiral fractures in all specimens. All methods were accurate and reliable predictors of K (cross-validation r(2)≥0.91; error≤13%), however FE models explained an additional 15% of the variance in measured Tult and illustrated 12-16% less error than DXA and QCT models. Given the strong correlations between measured and FE predicted K (cross-validation r(2)=0.95; error=10%) and Tult (cross-validation r(2)=0.91; error=9%), we believe the FE modeling procedure has reached a level of accuracy necessary to answer clinically relevant questions.