Global and Spatial Compartmental Interrelationships of Bone Density, Microstructure, Geometry and Biomechanics in the Distal Radius in a Colles' Fracture Study Using HR-pQCT

BACKGROUND

Bone parameters derived from HR-pQCT have been investigated on a parameter-by-parameter basis for different clinical conditions. However, little is known regarding the interrelationships of bone parameters and the spatial distribution of these interrelationships. In this work: 1) we investigate compartmental interrelationships of bone parameters; 2) assess the spatial distribution of interrelationships of bone parameters; and 3) compare interrelationships of bone parameters between postmenopausal women with and without a recent Colles' fracture.

METHODS

Images from the unaffected radius in fracture cases (n=84), and from the non-dominant radius of controls (n=98) were obtained using HR-pQCT. Trabecular voxel-based maps of local bone volume fraction (L.Tb.BV/TV), homogenized volumetric bone mineral density (H.Tb.BMD), homogenized μFEA-derived strain energy density (H.Tb.SED), and homogenized inter-trabecular distances (H.Tb.1/N) were generated; as well as surface-based maps of apparent cortical bone thickness (Surf.app.Ct.Th), porosity-weighted cortical bone thickness (Surf.Ct.SIT), mean cortical BMD (Surf.Ct.BMD), and mean cortical SED (Surf.Ct.SED). Anatomical correspondences across the parametric maps in the study were established via spatial normalization to a common template. Mean values of the parametric maps before spatial normalization were used to assess compartmental Spearman's rank partial correlations of bone parameters (e.g., between H.Tb.BMD and L.Tb.BV/TV or between Surf.Ct.BMD and Surf.app.Ct.Th). Spearman's rank partial correlations were also assessed for each voxel and vertex of the spatially normalized parametric maps, thus generating maps of Spearman's rank partial correlation coefficients. Correlations were performed independently within each group, and compared between groups using the Fisher's Z transformation.

RESULTS

All within-group global trabecular and cortical Spearman's rank partial correlations were significant; and the correlations of H.Tb.BMD-L.Tb.BV/TV, H.Tb.BMD-H.Tb.1/N, L.Tb.BV/TV-H.Tb.1/N, Surf.Ct.BMD-Surf.Ct.SED and Surf.Ct.SIT-Surf.Ct.SED were significantly different between controls and fracture cases. The spatial analyses revealed significant heterogeneous voxel- and surface-based correlation coefficient maps across the distal radius for both groups; and the correlation maps of H.Tb.BMD-L.Tb.BV/TV, H.Tb.BMD-H.Tb.1/N, L.Tb.BV/TV-H.Tb.1/N, H.Tb.1/N-H.Tb.SED and Surf.app.Ct.Th - Surf.Ct.SIT yielded small clusters of significant correlation differences between groups.

DISCUSSION

The heterogeneous spatial distribution of interrelationships of bone parameters assessing density, microstructure, geometry and biomechanics, along with their global and local differences between controls and fracture cases, may help us further understand different bone mechanisms of bone fracture.

Complex transradial carpal dislocation in a Professional Pianist: Case Report

Carpal fracture-dislocation associated to distal radius fractures is an uncommon injury of the wrist. Clinical assessment, instrumental diagnosis and treatment are all challenges for the surgeon. In addition, the prognosis in high-functioning patients is nearly always poor. The authors describe an early diagnosis of scapholunate dissociation and joint capsule tear associated with radial styloid and triquetral fractures in a 39-year-old professional piano player. A dorsal approach was used to reduce and fixate the fracture with k-wires, and to repair soft-tissue injuries with a Titanium micro-anchor. Early controlled mobilization was prescribed post-operatively. No other similar investigations were found because of the various associated fractures in the current case study, which normally excludes subjects from retrospective outcome studies on wrist ligament repair. Early diagnosis and surgical management associated with early controlled mobilization resulted in excellent clinical outcomes, according to radiograph imaging, the Italian version of the DASH score (Disabilities of the Arm, Shoulder and Hand), goniometry and dynamometry.

[Bone disease with Pain. Colles' fracture]

The distal radius is one of the most commonly fractured long bone. Colles' fracture results from a fall on the dorsiflexed and pronated hand. The dinner-fork deformity is the typical deformity of the Colles' fracture. For patients with no or a little displacement, conservative treatment is applied. The non-bridge type external fixator is applied for patients without an intra articular fracture. For patients with a comminuted fracture, the locking plate (volar approach) is recommended. During the healing period, shoulder, elbow and finger exercise should be insisted.

Recognising and treating Colles' type fractures in emergency care settings

In this article, the author explains how to identify a Colles' type fracture, explains how to insert a haematoma block, and gives a step by step guide to reducing this type of fracture.

[Loco typico radius fractures--personal experience]

Fractura radii loco typico (FRLT) is the fracture of the distal radius. That is the one of the most frequent fractures of locomotor system with the widest range of treatment in traumatology. Therapy depends on the stability of the fracture: nonoperative or operative. We analysed the five-year experience of our Department of Traumatology where more than 1500 patients with FRLT have been treated in the urgent surgery clinic and 126 of them were hospitalized. In our study we evaluated the results of the operative treatment and postoperative functional status of a treated wrist. According to the A-O classification, we hospitalized 36 patients with A type, 28 patients with B type, and 62 patients with C type of FRLT. We operated 80 patients. The postoperative functional status of a treated wrist was excellent or good in 64 patients and good in 16 patients. The treatment of FRLT depends on the type and the complications of the fracture and the age of the patients. Operative therapy is indicated in the unstable FRLT or after an inadequate nonoperative treatment.

[Screening for postmenopausal osteoporosis. Women with distal radius fractures should be evaluated for bone density]

In a case-control study at two country hospitals in Sweden, 110 consecutive postmenopausal women (age 50-75) with distal radius fracture were examined with the DXA-technique, on the injured radius, lumbar spine, and the right hip within three weeks after the fracture occurrence. Data was compared with 55 age-matched controls from The Swedish Population Register. The incidence of osteoporosis according to WHO's definition (T-score < -2.5) at any measurement site was higher in the fracture group, 44 per cent compared with 27 per cent in the control group. The fracture group had 12 per cent lower bone mineral density in the distal radius compared with the control group. A higher rate of previous fractures was noted in the fracture group compared with the control group. The study reflects the situation in general health care, where osteoporosis is common in postmenopausal women with distal radius fracture. This patient group can easily be identified and is suitable to be diagnosed for osteoporosis using bone density measurement prior to a decision being reached with regard to any treatment. According to the guideline for medical treatment (T-score < -2.0 and fragile-fracture) as outlined by the Swedish Osteoporosis Society, 75 per cent of postmenopausal patients with forearm fracture should be considered for such treatment.

Distal radius fractures in adults

Although distal radius fractures are a common injury in the elderly and young adult population, the classification, treatment options, and assessment of outcomes of these fractures remain controversial. Since there is no uniform fracture classification system, it is difficult to compare studies. An evidence-based model of management needs to be developed.

[Trauma of the bones of the hand and wrist]

Fractures of the distal radius are common counting for 17 percent of all fractures. With conventional radiography they can be classified readily. Magnetic resonance imaging (MRI) is a suitable technique for the detection of occult forms of fractures and of associated soft tissue injuries. In the wrist, fractures are 10 times less common than in the distal radius, with the scaphoid bone to be involved most commonly. Indications for computed tomography (CT) are complex fractures, occult fractures, or dislocations. MRI should be performed to evaluate the soft tissues, to detect occult fractures, or to analyse osteochondral lesions. Indications for arthrography are injuries of the ligaments or of the joint capsule. Fractures and dislocations of the metacarpal, and the phalangeal bones are the most common fractures of the skeletal system. Conventional radiography is the primary imaging technique, followed by sonography and MRI to detect injuries of the ligaments and tendons.

Absolute fracture risk varies with bone densitometry technique used. A theoretical and in vivo study of fracture cases

The lack of consensus of how the results of peripheral bone mineral density (BMD) measurements should be interpreted is proving a barrier to the wider use of these devices. One approach is to interpret peripheral measurements using thresholds (so-called equivalent T-scores) defined to have the same absolute fracture risk as a femoral neck T-score of -2.5. For this concept to be valid, the estimates of fracture risk for a population should be the same irrespective of the measurement technique used. We tested this prediction both theoretically and in vivo using data for 63 postmenopausal women with Colles fracture and 191 control subjects. The theoretical analysis showed that if the normal population has a Gaussian BMD distribution and fracture risk varies exponentially with Z-score as exp(-beta Z) then patients who experience a low-trauma fracture have a fracture risk that is larger by a factor exp(beta(2)) compared with the fracture risk of the whole population. Using data from the in vivo study, fracture risk predictions were compared for seven different types of measurement (lumbar spine; femoral neck; total hip BMD; and speed of sound [SOS] at the radius, tibia, phalanx, and metatarsal). When quantitative estimates of fracture risk were made for individual subjects, the average risk of fracture for the Colles group varied between 1.03 times larger (for tibial SOS) and 2.77 times larger (for total hip BMD) than the average fracture risk for the whole population. As predicted by the theoretical study, fracture risk varied according to the odds ratio determined by logistic regression analysis. Therefore, estimates of fracture risk derived for the same group of patients varied almost threefold according to the type of measurement. It was concluded that equating estimates of absolute fracture risk for different types of scan should not be used as the basis of deriving equivalent T-scores for interpreting peripheral measurements.

Cost effectiveness analysis of BMD referral for DXA using ultrasound as a selective pre-screen in a group of women with low trauma Colles' fractures

Measurements of bone density (BMD) are central to the World Health Organisation (WHO) approach to the definition of osteoporosis. Dual energy X- ray absorptiometry (DXA) remains the gold standard technique for measuring the bone mineral density (BMD) but Quantitative Ultrasound (QUS) is an attractive alternative method of bone assessment because it is easy to use and relatively inexpensive. It has been suggested that QUS could be used as a selective population pre-screen, to maximise the cost effectiveness of referral for DXA assessment of BMD. We set out to examine how such an approach might perform in the assessment of women with low trauma Colles' fracture. In 46 women aged 50-80 (mean 67) years we used DXA to measure BMD at lumbar spine and hip, and heel bone ultrasound to measure Broad Band Attenuation (BUA) and Velocity of Sound (VOS). We calculated local costs of pounds sterling 45 for DXA and pounds sterling 15 for QUS. We identified a BUA threshold of 60 dB/MHz as most cost effective as pre-screen, and calculated a sensitivity of 93% and specificity of 84% in identifying those subjects who were subsequently identified as having osteoporosis by DXA. DXA assessment of all patients had a cost of pounds sterling 77 per osteoporotic subject identified. We examined the cost-effectiveness of using QUS as a pre-screen, only referring subjects for more expensive DXA assessment if BUA was less than 60 dB/MHz. However this approach had no advantage, still costing pounds sterling 78 per osteoporotic subject identified. QUS assessment does not appear cost-effective as a pre-screen for DXA, even in this high risk group of women with low trauma Colles' fracture. A QUS pre-screen would only be cost-effective if the scan could be performed at a substantially lower cost.

Geometric properties of distal radius and pathogenesis of Colles fracture: a peripheral quantitative computed tomography study

It is well known among clinicians that Colles fracture patients may have normal projected axial bone mineral density and that bone mass is not synonymous with bone strength. The aim of this work was to investigate whether cross-sectional properties of the distal radius in female patients with recent Colles fracture differ from those of a younger group of normal women without fracture. It was hypothesized that patients with Colles fracture had petite distal radii and that cortical thinning and reduced cortical and trabecular volumetric density are dominant features of this fracture type. We used a multilayer high-precision peripheral quantitative computed tomography (pQCT) device with a long-term precision error of 0.1% for a dedicated phantom during the measurement period (152 d). Clinical measurements were made at an ultradistal site rich in trabecular bone and a less ultradistal site rich in cortical bone. The results show that the following pQCT variables were significantly reduced in the nonfractured radius of the Colles fracture cases: mean ultradistal trabecular volumetric density, mean ultradistal and distal cortical volumetric density, mean ultradistal and distal cortical thickness (p < 0.001 for all differences). The outer cortical diameter, cross-sectional bone area, and cortical bending moment of inertia were not statistically different in the two groups. Thus, it would appear that Colles fracture cases did not have petite distal radii. The results suggest that the deforming force of Colles fracture has a transaxial direction (fall on outstretched arm), resulting in a crush fracture, and that it is not a bending force. We suggest that Colles fracture occurs as a result of the combined effect of a fall on the out-stretched arm, low trabecular and cortical volumetric bone density, and reduced cortical thickness.

Unmet need in osteoporosis

OBJECTIVE

To audit the management of females presenting to Accident and Emergency department with a diagnosis of low impact Colles fracture.

DESIGN

Telephone questionnaire of 50 patients who attended A & E in 1998 with diagnosis of Colles fracture

SETTING

Glasgow Royal Infirmary within North Glasgow catchment area.

SUBJECTS

Women between 45-79 years of age who attended Accident and Emergency Department in 1998 with a diagnosis of low impact Colles fracture.

RESULTS

Mean age was 63 years (range 44-78): ninety percent were post menopausal and 40% of the total group were smokers. Twenty six percent had a positive family history of osteoporosis, 24% had undergone hysterectomy and 88% took no part in any load bearing exercise. Ten percent (n = 5) were on treatment (1 alendronate, 3 etidronate with calcium, 1 hormone replacement therapy)

CONCLUSION

A significant proportion of our study population have multiple risk factors for osteoporosis which are not being addressed. Raising awareness in orthopaedic surgeons, family doctors and patients is urgently required.

Clodronate increases mineralization of callus after Colles' fracture: a randomized, double-blind, placebo-controlled, prospective trial in 32 patients

In a randomized study of 32 postmenopausal women with a Colles' fracture, we studied whether 8 weeks of treatment with clodronate, a bisphosphonate, could prevent posttraumatic osteopenia. The patients were treated with a plaster splint for 4 weeks. The bone mineral density (BMD) of the forearm bones was measured at 2 levels with dual-energy x-ray absorptiometry (DEXA) 2, 6 and 12 months after the fracture. At 2 months, in the clodronate group, there was a median 53% higher BMD in the fracture region of the radius than in the uninjured radius. In the placebo group, we found a 33% higher BMD in the fractured radius at that level than in the uninjured radius. This increase in BMD of the fractured radius, caused by clodronate, was statistically significant. At 12 months, the BMD of the fracture side had been reduced by 17% and 12%, respectively, at that time it was still significantly increased in the clodronate group alone. In the ulna at the same level, we found no significant changes in BMD in either group on either side at any time. At 2 months, at the level between the distal and middle thirds, in the fractured radius, the median BMD was 7% lower in the clodronate group and 6% lower in the placebo group than in the uninjured radius. Although the reduction in BMD at that level was significant, there was no difference between the two treatment groups. At this level, the ulna on the fractured side showed a similar pattern, with a 5% lower BMD in the clodronate group and a 4% lower BMD in the placebo group. This osteopenia showed a small but significant progression on the fractured side after 6 and 12 months.

Upper extremity disorders in women

Carpal tunnel syndrome, Colles' fracture, and osteoarthritis of the basilar joint of the thumb are only three of the many upper extremity conditions that preferentially affect women. With more and more women entering the workplace, these conditions become more disruptive of patients' lifestyles and even may be increasing in incidence. Orthopaedic surgeons traditionally have focused on the surgical treatment of patients with these conditions, but it is becoming increasingly clear that surgeons also must focus on delineating pathophysiology to better identify those individuals at risk and help prevent these potentially disabling disorders.

[Indices of mechanical strength of the distal radius in healthy women and women with Colles fracture]

Wrist fractures (Colles) are one of the most frequently observed osteoporotic fractures in postmenopausal women. The aim of our study was the comparison of mechanical properties of distal radius of women with Colles fracture using a Stratec XCT 960 peripheral quantitative computed tomography (pQCT) in relation to age-pair controls without a wrist fracture. Using the pQCT method for estimation of SSI (Strength Strain Index), we found significant differences of SSI values in Colles subjects. In clinical practice, pQCT offers new diagnostic tools which cannot be provided by conventional densitometric methods.

Load relaxation and forces with activity in Hoffman external fixators: a clinical study in patients with Colles' fractures

A small-frame Hoffman external fixation bar instrumented with strain gauges to quantify bending and torsional forces was applied to 4 patients with a displaced metaphyseal fracture of the distal radius. Measurements were taken during surgery as well as at 1, 3, and 6 weeks after surgery during activities of daily living and hand therapy mobilization. Radiographs also were taken before and after reduction and at each subsequent visit. Force decay occurred after reduction of the fracture, averaging only 26% of the initial distraction forces by 5 minutes. These forces plateaued and did not significantly change over the subsequent 40-minute observation period. There was no correlation between carpal height index and the forces measured in the external fixator. Significant changes in external fixator forces were measured during activities of daily living and hand therapy mobilization, but these returned to baseline after the activities were performed. The most provocative activities studied were twisting a doorknob and lifting heavy objects. These activities should be performed with caution by patients with unstable distal radial fractures.

Ipsilateral fractures of the proximal ulna and distal radius (Colles type)

A 43-year-old female fell backward outside her home while carrying a watering can. She sustained an ipsilateral fracture of the proximal ulna and distal radius (Colles fracture). The ulnar fracture was plated, and the Colles fracture was managed by closed reduction and percutaneous Kirschner wiring. The patient recovered without incident. This association of forearm fractures is unusual. Both fractures can be caused by a fall on the hand with the wrist in mid-extension and the elbow flexed, and they probably occurred in quick succession.

[Colles' fracture in a girl after fulguration]

In the present study we describe the case of a 11 years old child, female, who was accidentally fulgurated by the left arm and after has presented an episode of pallor, shaking, confusion, throbbing and tingle of the arms. For this reason she was admitted in our Department of Pediatrics, University of Rome "La Sapienza". The child presented also a moderate pain at the left wrist. For this reason was performed a wrist X Ray which showed an incomplete fracture of the distal extremity of the radial diaphysis, with a small ulnar infraction of the same side. Life parameters and the ECG were normal so as the blood exams, in particular the CPK and the LDH (in fact, they can be indication of muscular necrosis). In summary the Authors with this study would like to remark the necessity of to suspect a fracture in the place of admittance of the electric current, even if not immediately appear clean signs of oedema, pain and functional impotence.

Outcome after Colles fracture: the relative responsiveness of three questionnaires and physical examination measures

Clinical evaluation of outcome after Colles fracture has not been standardized. To assess the relative responsiveness of various clinical and questionnaire measures for the assessment of outcome after Colles fracture, 21 patients were surveyed on the day fracture immobilization was discontinued and again 3 months after that date with the following measures: a short form general health survey (SF-36), the Arthritis Impact Measurement Scale (AIMS2), the Brigham and Women's Hospital carpal tunnel questionnaire; pinch strength, grip strength, pressure sensibility, range of motion, and dexterity. Significant changes, all in the direction of improved health status, occurred in the following scales or measures: AIMS2 mobility, hand and finger function, arm function, household tasks, "arthritis" (fracture) pain, self-care, satisfaction, physical health, affect, and tension; Brigham function; SF-36 physical role and mental health; and grip, pinch, dexterity, and range of motion. The impairments that occur after Colles fracture are multidimensional and are only partially captured by traditional physical measures. Questionnaires such as the SF-36, AIMS2, and Brigham and Women's instruments provide a mechanism to capture the function and symptom dimensions objectively.

Decision making in distal radius fractures

In distal radius fractures, function follows restoration of preinjury anatomic landmarks. The allowable deviation from these measurements is relatively small if optimal results are to be achieved, particularly in younger individuals. A hierarchy of treatment options--characterized by increasing invasiveness--exists for treating these injuries. As this hierarchy is ascended, treatment-related complications increase. It appears reasonable to select the least invasive treatment option capable of achieving satisfactory anatomic alignment. Hand and extremity function must be addressed early, and a conscientious effort must be exerted to avoid residual stiffness or the development of reflex sympathetic dystrophy.

Treatment of complex fractures of the distal radius. Combined use of internal and external fixation and arthroscopic reduction

A group of fractures of the distal radius are inherently unstable and cannot be treated by closed reduction and cast or external fixation. These fractures are high-energy motor vehicle accidents often seen in young adults but possible in nearly every age group. They are not typical Colles's fractures because they are intra-articular with displacement of the joint articular surfaces. The goals of treatment are to obtain an anatomic reduction and then to proceed with treatment techniques to maintain the reduction by whatever methods are available or necessary within the experience of the treating surgeon. Previous admonitions that Colles's fractures should not be treated by open reduction are incorrect. Like other intra-articular fractures, the goal is anatomic alignment. Limited open reduction or newer arthroscopic techniques may be sufficient. A more aggressive approach of open reduction, internal and external fixation, and autogenous bone grafting is now indicated in most high-energy distal radius fractures to achieve the treatment goals defined earlier: anatomic joint surface reduction, restoration of radial length, and correction of dorsal malangulation.

[Eponyms of distal radius fractures. Colles-Pouteau, Smith-Goyrand and Barton fractures and their importance in the trauma surgery patient sample]

Fractures at the distal end of the radius are quite common. So, these fractures are well known to represent consequences of industrial accidents leading to temporary unfitness for work, too. Eponym descriptions of fractures may mislead authors and readers as well if used in a non-uniform way in medical literature. Using the original articles of the first describing authors a clear distinction of eponyms concerning fractures near to the wrist joint is given. The authors of this feature report of the clinical experience in treatment and results of distal radius fractures in combination with aspects of expert opinions on these fractures.

Incidence of Colles' fracture in a North American community

In a 30-year period, 1,137 adult residents of Rochester, Minnesota experienced 1235 Colles' fractures. Fracture incidence among women increased over sixfold between ages 35-39 and 60-64 and then leveled off. Male rates were lower in every age group and did not rise as dramatically. Fractures associated with moderate trauma were responsible for the increased incidence with age and the excess among women. Overall, Rochester rates were 30 per cent or more greater than those reported from communities in other countries (Am J Public Health 1982; 72:605-607.).

Colles fracture due to weightlifting

The case report of a weightlifter who sustained a Colles fracture is described. Wrist injuries sustained in weightlifitng are reviewed. They highlight the need for proper instruction and supervision in this sport.

External pin fixation for unstable Colles' fractures

During a five-year period, a double-pin Roger Anderson apparatus, with pins perpendicularly placed in the second and third metacarpals and in the distal part of the radius, was applied in 130 patients with an unstable Colles fracture. Sixty of the 130 were followed for two years. Shortening was limited to a median of two millimeters and dorsal angulation, to a median of 3 degrees. Wrist dorsiflexion averaged 58 degrees, and volar flexion averaged 50 degrees. Pronation and supination had an average loss of 5 degrees when compared with the uninjured side. Repeat reduction was required in only three patients. Patient assessment revealed that 85 per cent of the patients had good results; 12 per cent, fair; and 3 per cent, unsatisfactory. Objective analysis (McBride system) revealed that 90 per cent had good to excellent results; 8 per cent, fair; and 2 per cent, poor. Ninety-two per cent had no pain, 89 per cent had no deformity, and the mean grip strength was twenty kilograms. Sixteen patients had complications; seven of the sixteen had pin loosening, which occurred most frequently late during the course of treatment and without adverse sequelae.