The epidemiology of fractures of the proximal femur

Between 1980 and 1989, reports on 21,145 fractures of the proximal part of the femur (15,428 women and 5,717 men) were collected by AO Documentation and are analysed in the present paper. The number of fractures increases exponentially with age for women and for men. Up to 50, the number of fractures is higher for men than for women and vice versa after 55 years. The exponential increase in the number of fractures with age appears for all the types A1 to B3 for both women and men. No special increase has been identified for women after 50 (expected age of menopause).

[Immobilization osteoporosis and fracture in children]

This study was intended to enhance the diagnostic vigilance of immobilization osteoporosis with fracture and explore its prevention and treatment. Thirteen children with the hip disease underwent one to nine months of plaster cast after operation. A retrospective analysis was made on these 13 patients with fracture and immobilization osteoporosis. The result showed that disuse fracture occurred in fifteen places of their femora. All of these cases were cured by non-operative and drug treatment. These data suggest that for the cases of immobilization osteoporosis it is important to prevent fracture by means of early diagnosis, proper drugs, early function exercise, appropriately shorter period of fixation and the avoidance of trauma.

Stress fracture in military recruits: gender differences in muscle and bone susceptibility factors

A total of 693 female U.S. Marine Corps recruits were studied with anthropometry and dual-energy X-ray absorptiometry (DXA) scans of the midthigh and distal third of the lower leg prior to a 12 week physical training program. In this group, 37 incident stress fracture cases were radiologically confirmed. Female data were compared with male data from an earlier study of 626 Marine recruits extended with additional cases for a total of 38 stress fracture cases. Using DXA data, bone structural geometry and cortical dimensions were derived at scan locations and muscle cross-sectional area was computed at the midthigh. Measurements were compared within gender between pooled fracture cases and controls after excluding subjects diagnosed with shin splints. In both genders, fracture cases were less physically fit, and had smaller thigh muscles compared with controls. After correction for height and weight, section moduli (Z) and bone strength indices (Z/bone length) of the femur and tibia were significantly smaller in fracture cases of both genders, but patterns differed. Female cases had thinner cortices and lower areal bone mineral density (BMD), whereas male cases had externally narrower bones but similar cortical thicknesses and areal BMDs compared with controls. In both genders, differences in fitness, muscle, and bone parameters suggest poor skeletal adaptation in fracture cases due to inadequate physical conditioning prior to training. To determine whether bone and muscle strength parameters differed between genders, all data were pooled and adjusted for height and weight. In both the tibia and femur, men had significantly larger section moduli and bone strength indices than women, although women had higher tibia but lower femur areal BMDs. Female bones, on average, were narrower and had thinner cortices (not significant in the femur, p = 0.07). Unlike the bone geometry differences, thigh muscle cross-sectional areas were virtually identical to those of the men, suggesting that the muscles of the women were not relatively weaker.

[Osteoporosis: the epidemiologic and health economics perspective]

Epidemiology of osteoporosis reveals some specific properties with considerable consequences on economic and social aspects, which are discussed briefly. Large parts of an aging population are under risk of developing osteoporosis with consecutive morbidity and mortality. The epidemiological consequences and economic burden will increase during the next 20 years due to demographic changes. Proximal femoral fractures are most important causing relevant mortality and, if survived, regularly relevant functional loss. Due to the increasing importance of osteoporosis, efficient age-adapted strategies in diagnosis and therapy need to be developed.

The consequences of anterior femoral notching in total knee arthroplasty. A biomechanical study

BACKGROUND

Notching of the anterior femoral cortex during total knee arthroplasty has been implicated as a cause of subsequent periprosthetic supracondylar femoral fracture. However, other than observational clinical data, no reliable association between these events has been established, to our knowledge. The purpose of the present study was to investigate the biomechanical effects of notching of the anterior femoral cortex.

METHODS

The femoral component of a total knee replacement was implanted in twelve matched pairs of human cadaveric femora; one specimen in each pair had preservation of the anterior femoral cortex, and the other had a full-thickness cortical defect created just proximal to the anterior flange of the femoral component. The pairs were then subjected to either bending or torsional loading to failure. Both the fracture pattern and the quantitative load to failure were analyzed. Two matched pairs were excluded from the analysis because of inadvertent fracture during placement of the component.

RESULTS

Following the application of a bending load, femora with notching of the anterior femoral cortex sustained a short oblique fracture that originated at the cortical defect proximal to the femoral component and femora without notching had a midshaft fracture. In contrast, notching of the anterior femoral cortex had no effect on the fracture pattern that was observed after the application of a torsional load. The mean load to failure was significantly reduced by notching in both testing modes. Notching decreased bending strength from 11,813 to 9690 newtons (18 percent; p = 0.0034), and it decreased torsional strength from 134.7 to 81.8 newton-meters (39.2 percent; p = 0.01).

CONCLUSIONS

Biomechanical testing demonstrated that notching of the anterior femoral cortex significantly lessens the load to failure following total knee arthroplasty and influences the subsequent fracture pattern. These effects are manifested in different ways under the two loading conditions: the fracture pattern is altered under bending load, and there is a greater quantitative decrease in load to failure with torsional loading.

CLINICAL RELEVANCE

Weakening of the femur by notching of the anterior cortex after total knee arthroplasty may warrant alteration in the customary postoperative regimen for these patients. Manipulation of a total knee replacement with a notched anterior femoral cortex should probably be avoided.

Limb salvage surgery for pathological fractures in osteosarcoma

The local treatment of pathological fracture in patients with a primary osteosarcoma remains controversial. In this paper we report the oncological outcome of the treatment of pathological fractures in 18 patients suffering from this disease. There were ten male and eight female patients, and the average age at diagnosis was 17 years. All patients received adjuvant chemotherapy. Wide resections were performed in 17, but in one there was 'contamination' of the margins of the excision. Skeletal reconstruction was performed with a locally designed and manufactured custom 'mega' prosthesis. The average follow-up was 33 months (range: 12-93 months), and 14 patients were alive on completion of the study. Local recurrence appeared in two patients, while three developed pulmonary metastases.

Fracture after distraction osteogenesis

We reviewed 173 patients undergoing distraction osteogenesis to determine the incidence, location and timing of fractures occurring as a complication of the procedure. There were 17 fractures in 180 lengthened segments giving an overall rate of fracture of 9.4%. Unexpectedly, the pattern and location of the fractures were very variable; six were within the regenerate itself, six at the junction between the regenerate and the original bone and five at distant sites in the limb. Of those occurring in the regenerate, five were noted to be associated with compression and partial collapse of the regenerate. In three patients collapse and deformity developed gradually in the distracted segment over the six months after removal of the frame. The method of treatment of these fractures should be chosen to take into account multiple factors, which are additional and often different from those to be considered during management of acute traumatic injuries. Internal fixation appears to be most appropriate for displaced fractures, although in small children, or in those in whom there has been, or is, infection of the screw tracks, a new period of treatment using external fixation may be needed. Fixation by intramedullary nailing was associated with a risk of infection, even if screw tracks were assessed as healthy at the time of insertion of the nail. Internal fixation with the use of plates is safe for displaced, unstable fractures in children.

Contralateral hip fractures - can predisposing factors be determined?

A case control study was carried out in the Orthopaedic Department of Bradford Royal Infirmary in an attempt to see if certain medical conditions, which can affect balance and stability, are more common in those who sustain a second proximal femoral fracture. Medical conditions included in the study were: late effects of cerebro-vascular accident, blindness, syncope and collapse, alcoholism, Alzheimer's disease, epilepsy, Parkinsonism, ischaemic heart disease and senile dementia. The study group comprised 53 patients admitted to hospital between 1992 and 1998 with two separate proximal femoral fractures each on a different side. The control group comprised 530 patients selected from a general pool of 2080 proximal femoral fracture patients admitted to hospital during the same period. The control group patients were matched to the study group for age, sex, and time of occurrence of the first fracture. Results show significantly higher association of late effects of cerebro-vascular accident, blindness, syncope and collapse, and Alzheimer's disease with subsequent contralateral proximal femoral fractures. This study supports a causal relationship between the above medical conditions and subsequent contralateral proximal femoral fractures. It may therefore be possible to identify patients who are at risk of returning with a second fracture.

Accidental and nonaccidental femur fractures in children

A retrospective review of 207 patients younger than 6 years of age who sustained nonpathologic diaphyseal femur fractures was done, which emphasized the characteristics of accidental versus nonaccidental injury. There were 214 fractures in 123 boys and 83 girls (the gender of one patient was unknown). The average age of the patients was 2.73 years. Mechanisms of injury were pedestrian struck by a car (62 patients), falls (92 patients), and motor vehicle accidents (10 patients). Nineteen patients did not have a history of trauma. Seventy-six cases were investigated for child abuse. The results of 13 investigations were positive. Overall, the morphologic features of the fractures were transverse (38%), spiral (27%), and oblique (17%). In the investigated group, 27% of the fractures were transverse, 39% were spiral, and 15% were oblique. In those cases with positive results of the investigation, 36% of the fractures were transverse, 36% were spiral, and 7% were oblique. Although transverse fractures are most common in accidental and nonaccidental injuries, many practitioners think spiral fractures are pathognomonic of abuse. The current data show that although spiral fractures were less common than transverse fractures overall, and no more common in the cohort of patients in whom the results of the child abuse investigations were positive, they were overrepresented in the cohort that was investigated. This suggests that spiral fractures are viewed as particularly suspicious, which may lead to missed cases of nonaccidental injury in children with transverse fractures.

Femur shaft fractures in toddlers and young children: rarely from child abuse

One hundred thirty-nine children younger than 4 years were identified retrospectively from the period of 1993 through 1997 to have an isolated fracture of the shaft of one or both femurs. Abuse was classified as group A (definite, likely, or questionable abuse) or group B (unknown cause, questionable accident, likely accident, or definite accident). The average age of the children was 2.3 +/- 1.1 years. Thirteen children, 9% of the total group, average age of 1.1 +/- 1.0 years, were likely to have been abused (group A). A total of 126 children, 91% of the total, average age 2.3 +/- 1.0 years, sustained their fracture most likely as a result of an accident (group B). Whether a child had not yet achieved walking age (toddler) was the strongest predictor of likely abuse. Ten (42%) of 24 of nonwalking children were in group A, whereas only three (2.6%) of 115 of walking children were in group A (p < 0.001). Child Protective Services may have been unnecessary in 42-63% of cases. Unless other evidence of abuse such as an inconsistent story, bruises, or other fractures are present, abuse is very unlikely to be involved in the walking-age child, analogous to the toddler fracture of the tibia.

Primary hyperparathyroidism as a cause of multiple long bone fractures in a young Nigerian adult

Primary hyperparathyroidism is a recognized though relatively rare cause of multiple limbs fractures. We report a case in a young Nigerian adult. It is emphasize that primary hyperparathyroidism may be asymptomatic and therefore under-recognized in this environment because it is very uncommon.

Fixation of periprosthetic femoral shaft fractures occurring at the tip of the stem: a biomechanical study of 5 techniques

This study evaluated 5 currently used periprosthetic femoral shaft fracture fixation techniques to determine which technique provided the greatest fixation stability. Periprosthetic fractures in 30 synthetic femurs were fixed with a plate with cables, plate with proximal cables and distal bicortical screws (Ogden concept), plate with proximal unicortical screws and distal bicortical screws, plate with proximal unicortical screws and cables and distal bicortical screws, or 2 allograft cortical strut grafts with cables. These specimens were then tested in 3 physiologic loading modes. The plate constructs with proximal unicortical screws and distal bicortical screws or with proximal unicortical screws, proximal cables, and distal bicortical screws were significantly more stable in axial compression, lateral bending, and torsional loading than the other fixation constructs studied.

Femoral metastatic fractures treated with intramedullary nailing

Between 1993 and 1998, 49 consecutive patients with impending or complete pathological fractures of the femur due to metastatic bone disease were treated with intramedullary nailing. Twenty-four were treated with a long Gamma nail and 32 with an AO nail with a cephalomedullary spiral blade. Both implants gave a good functional result with relief of pain and improved mobility with no difference in morbidity between either group (P>0.05).

Features of femoral fractures in nonaccidental injury

Femoral fracture is one of the most common long bone fractures owing to nonaccidental injury, but there is little evidence in the literature about their characteristics. It is important medicolegally to establish a diagnosis of child abuse. Fourteen femoral fractures from definite nonaccidental injury were analysed and compared with 33 femoral fractures caused by definite accident. The age, site, and fracture patterns were carefully studied. Of inflicted femoral fractures, 92.8% (13 of 14) occurred in children younger than 1 year old. On studying the fracture morphology, we conclude that there is no specific roentgenographic site or fracture pattern that allows differentiation between accidental and nonaccidental femoral fractures.

The saddle prosthesis in pelvic primary and secondary musculoskeletal tumors: functional results at several postoperative intervals

The first purpose of this study was to evaluate the saddle prosthesis in patients with periacetabular tumors in terms of the functional results obtained after several postoperative intervals. The second purpose was to evaluate the complications and how they might be prevented in the future. Functional results according to the MSTS functional rating system were evaluated at several postoperative intervals in 15 patients treated with internal hemipelvectomy and reconstruction with the saddle prosthesis because of periacetabular primary (n = 9) or secondary (n = 6) malignancies. All complications were evaluated. Three months postoperatively, 7/9 patients with a primary tumor and 2/4 patients with a secondary tumor were able to walk outside without pain. Median functional results 3 and 6 months postoperatively were 40% and 50%, respectively. Deep infection occurred in 4 patients and fracture of the iliac remnant in 2. Heterotopic ossifications along the interpositional component were seen in 5 patients, but they did not negatively influence the functional outcome. Three (relative) contraindications to reconstruction with the saddle prosthesis could be ascertained: osteoporosis, extended involvement of the iliac wing by tumor, and insufficient soft-tissue quality after previous procedures. (Short-term) functional results after reconstruction with the saddle prosthesis are satisfactory if the above-mentioned contraindications are taken into consideration.

The incidence of acute cardiorespiratory and vascular dysfunction following intramedullary nail fixation of femoral metastasis

Intramedullary nail fixation is a common treatment for metastatic tumors of the femur with overt or impending femoral fracture. This procedure sometimes causes severe cardiorespiratory and vascular dysfunction. The clinical relevance of this is not dear. We reviewed 45 operations in 43 patients, where intramedullary nail fixation was used to treat metastatic femoral fractures and impending fractures. We studied the incidence of intraoperative oxygen desaturation and hypotension associated with intramedullary manipulation as markers of cardiorespiratory and vascular dysfunction. Acute oxygen desaturation and hypotension occurred in 11 of our 45 patients. Of these, 3 died, 2 required intensive care postoperatively and 6 made uneventful recoveries. We hope to highlight a serious complication in this patient group.

Fracture mechanics. A comparison study of torsional stress on bone

Fractures that result from torsional loading of shafts in mechanical systems of nonbiologic materials generate a fracture line that forms a 45 degrees angle to an axis that is perpendicular to the direction of torsional loading on the shaft. As tension and compression are applied to these isotropic substances, the angle of fracture increases and decreases, respectively. Understanding how these forces, particularly compressive forces, generate elongation of a spiral fracture increases the ability to predict the extent of injury to bone. Fibular and metatarsal fractures are of primary importance to the podiatric physician, but any spiral fracture may be subject to torsional loading. Thus the principles stated here apply to the entire skeletal system. The purpose of this article is to provide a better understanding of the mechanics behind the causes and characteristics of fractures and to explore whether these same factors apply to the fracture mechanics of bone.

[Compartment syndrome of the thigh with sciatic nerve paralysis]

Acute compartment syndrome of the thigh has been infrequently reported in the literature. Closed femoral fractures and blunt soft tissue trauma are the main causes of this injury. The multiple injured patient in this case report developed a compartment syndrome of the thigh after intramedullary nailing of a comminuted fracture of the femur. Fasciotomy was performed two days after surgery because of extense swelling of the thigh in the ventilated and sedated patient. Sciatic and femoral nerve palsy was recognized after extubation of the patient nine days after the injury. During the following weeks the paresis of the femoral nerve recovered but neither motor nor sensory function of the sciatic nerve could be demonstrated. Therefore an operative revision of the sciatic nerve was performed eighteen weeks after trauma. No direct nerve injury could be detected but there were adhesions around the nerve as a sign of compression neuropathy caused by the compartment syndrome. The tibial component of the sciatic nerve showed a complete recovery within the next months but there was a persisting peroneal nerve palsy.

CONCLUSION

Early clinical symptoms of a compartment syndrome like pain, paresthesia and paresis can not be ascertained in a ventilated and sedated patient. Tense swelling of the muscles is often the only detectable sign. Frequent measurements of compartment pressure should be done in these patients. We suggest early decompressive fasciotomy because the morbidity caused by fasciotomy in a borderline compartment syndrome is far outweighed by the morbidity that accompanies an undiagnosed untreated compartment syndrome with possible nerve palsy.

Risk of complications from bone metastases in breast cancer. implications for management

A retrospective analysis of 859 patients who developed bone metastases from breast cancer between 1975 and 1991 was performed in order to identify factors that predict for complications from skeletal disease. The patients were divided into four groups based on the sites of disease at diagnosis of skeletal metastases: bone disease only; bone and soft tissue disease; bone and pleuro-pulmonary disease; bone and liver disease. Patients with metastatic disease confined to the skeleton were most likely to develop a pathological fracture. The time to long bone fracture was similar for all groups, but the least number of such fractures occurred in patients with bone and liver metastases since their survival was shortest (median: 5.5 months; P<0.001). Patients with bone metastases only were most likely to require radiotherapy to painful osseous deposits (P=0.0001) and most rapidly developed spinal cord compression (P=0.01, data not shown). The results suggest that patients with disease confined to the skeleton at the diagnosis of bone metastases are most likely to develop skeletal-related complications from advanced breast cancer. Such patients may benefit most from treatment with bisphosphonates.

Population based epidemiologic and morphologic study of femoral shaft fractures

The epidemiologic and morphologic features of all femoral shaft fractures in skeletally mature patients treated during a 10-year period in a semi-urban county were analyzed. Among an average adult population of 202,592 residents, 192 people sustained 201 traumatic femoral shaft fractures during the study period. The incidence was 9.9 fractures per 100,000 person-years. The highest age and gender specific incidences were seen in males from 15 to 24 years of age and in females 75 years of age or older. Seventy-five percent (151) of the fractures were the result of a high-energy trauma, 131 of which occurred in road traffic accidents. Unexpectedly, there were 50 low-energy fractures. Fractures of the middle 1/3 of the diaphysis were 79%. The majority, 155 (77%), of all fractures were transverse, oblique, or oblique transverse. Regarding the degree of comminution, the Winquist and Hansen Grade 0 (noncomminuted) fracture was the most common. Forty-eight percent of fractures were AO Type A, 39% were Type B, and 13% were Type C fractures. Of the 25 open fractures, 14 were Gustilo Type II. All six Type III open injuries were Type IIIA. Based on the data from the current study, most of the femoral fractures in this community might be treated adequately with conventional intramedullary nails, rather than using interlocking nails, provided the stability of fixation and fracture alignment can be maintained. Preventive measures against femoral shaft fractures should focus on protection of automobile drivers, especially young men, and on effective treatment of osteoporosis in elderly women.

Prediction of femoral fracture load using finite element models: an examination of stress- and strain-based failure theories

Finite element (FE) models are often used to model bone failure. However, no failure theory for bone has been validated at this time. In this study, we examined the performance of nine stress- and strain-based failure theories, six of which could account for differences in tensile and compressive material strengths. The distortion energy, Hoffman and a strain-based Hoffman analog, maximum normal stress, maximum normal strain, maximum shear strain, maximum shear stress (tau(max)), Coulomb-Mohr, and modified Mohr failure theories were evaluated using automatically generated, computed tomographic scan-based FE models of the femur. Eighteen matched pairs of proximal femora were examined in two load configurations, one approximating joint loading during single-limb stance and one simulating impact from a fall. Mechanical testing was performed to assess model and failure theory performance in the context of predicting femoral fracture load. Measured and FE-computed fracture load were significantly correlated for both loading conditions and all failure criteria (p < or = 0.001). The distortion energy and tau(max) failure theories were the most robust of those examined, providing the most consistently strong FE model performance for two very different loading conditions. The more complex failure theories and the strain-based theories examined did not improve performance over the simpler distortion energy and tau(max) theories, and often degraded performance, even when differences between tensile and compressive failure properties were represented. The relatively strong performance of the distortion energy and tau(max) theories supports the hypothesis that shear/distortion is an important failure mode during femoral fracture.