Regional differences in cortical porosity in the fractured femoral neck.

Although bone mass is a contributory risk factor for intracapsular hip fracture, its distribution and porosity within the femoral neck is also important for bone strength. In femoral neck biopsies from 13 women with intracapsular hip fracture (mean +/- SEM: 75.4+/-2.1 years, OP) and 19 cadaveric samples (9 men and 10 women [control], aged 79.4+/-1.7 years), a segmental analysis was used to quantify circumferential variations in the characteristics of cortical bone haversian systems. In female control femoral necks, there was an increasing porosity gradient between the inferior (I) (7.7+/-0.6%) and superior regions (S) (16.05+/-1.8%,p < 0.005). In walking, these regions undergo compression and tension, respectively. In men, a similar trend was observed, but the differences were not significant (I: 11.1+/-1.2%; S: 14.1+/-1.7%; p = 0.133). This porosity gradient was not maintained in the fracture group (I: 10+/-1%; S: 12.65+/-1.2%). In contrast, porosity in the fracture group was greatest in the anterior cortex, being 41% higher in that quadrant than in controls (p = 0.06). The areal density of haversian canals ranged from 16.7 to 21.3 canals/mm2 with no significant differences between fractures and controls. In the control women, mean canal diameter was highest in the superior region (60+/-2.8 microm), and these canals were significantly larger than those in the inferior region (49.4+/-1.4 microm, p < 0.05). This difference was less marked in the fracture cases (I: 53.21+/-2.5 microm; S: 59.1+/-2.8 microm; p = 0.0878). Although the mean canal diameter in the anterior quadrant of the fracture cases was higher than in the control women this did not reach significance (OP/F: 59.5+/-3 microm; control/F: 52.7+/-2.6 microm; p = 0.106). However, the proportion of "giant" canals with diameters >385 microm (defined as the top 0.5% in the controls) was doubled in the anterior region of the fracture cases (OP/F: 1.28%; control/F: 0.69%; p < 0.005). Porosity is related to the square of the canal radius; therefore, such canals make a substantial contribution to cortical porosity. Previous work has shown that the elastic modulus of bone decreases approximately as the square root of porosity. Therefore, the increased porosity and the higher prevalence of "giant" canals have a markedly negative influence on the ability of the cortical shell to withstand stresses associated with a fall. The mechanisms responsible for the localized generation of "giant" haversian canals, and ultimately the "trabecularization" of the cortex, require further investigation.

Structure of the femoral neck in hip fracture: cortical bone loss in the inferoanterior to superoposterior axis.

Although bone mass is a contributory risk factor for hip fracture, its distribution about the femoral neck is also important. Femoral neck biopsies were obtained from 13 females with intracapsular hip fracture (fracture: mean age 74.3 +/- 2.3 years [SEM]) and 19 cadaveric samples (control: 9 males and 10 females 79.4 +/- 1.7 years) and the areas of cortical and cancellous bone were quantitated in octants. In the control group, although males had larger bones than females, the proportions of cortical and cancellous bone were not different (p > 0.05) between the genders. The total amount of bone, as a proportion of bone + marrow, was significantly reduced in the fractures compared with the female controls (%Tt.Ar: fracture 27.83 +/- 1.18, female control 33.62 +/- 1.47; p = 0.0054). Reductions in cortical bone area occurred in all regions but particularly in the inferior, inferoanterior, and anterior octants (p < 0.05). There were no differences between cases and controls in the regional amount of cancellous bone (all regions, p > 0.178). Marked reductions in mean cortical bone width between the fracture and female control group occurred in the anterior, inferoanterior (31%), and superoposterior (25%) regions. Representing cortical widths as simple Fourier functions of the angle about the center of area (R2adj = 0.79) showed in the cases that there was preservation of the cortical bone in the inferior region, with the proportional loss of cortical bone being greatest in the inferoanterior and superoposterior regions. It is concluded that loss of cortical, rather than cancellous, bone predominates in cases of femoral neck fracture. This loss occurs primarily along the inferoanterior to superoposterior axis. As this axis bears the greatest strain during a fall, it is hypothesized that specific thinning of the cortex in these regions leads to an exaggerated propensity to fracture in those so affected, above that resulting from an equivalent general decrease in bone mass.

Coregistration imaging of the foot. A new localisation technique.

We describe a new technique, known as coregistration imaging, which superimposes 99mTc isotope bone scans on to plain radiographs. We used the technique selectively in cases in which the nuclear medicine physician, who reported the isotope scan, had difficulty in localising the anatomical site of the abnormality. In the forefoot, coregistration of isotope scans did not help to localise pathology; the scan alone gave sufficient detail. In 17 patients with pain in the hind- and midfoot, isotope scanning identified eight sites of abnormality in those with normal radiographs. In those with more than one abnormality on plain radiographs the isotope scan eliminated 12 sites of suspicion. Coregistration of the images significantly increased the certainty of localisation of disease (p < 0.001). We recommend the selective use of coregistration scanning as a useful technique for investigating patients with pain in the foot and ankle.

First metacarpal osteotomy for trapeziometacarpal osteoarthritis.

We report a long-term follow-up of abduction-extension osteotomy of the first metacarpal, performed for painful trapeziometacarpal osteoarthritis. Of a consecutive series of 50 operations, 41 thumbs (82%) were reviewed at a mean follow-up of 6.8 years. Good or excellent pain relief was achieved in 80%, and 93% considered that surgery had improved hand function, while 82% had normal grip and pinch strength, with restoration of thumb abduction. Metacarpal osteotomy was equally successful in relieving symptoms of those with early (grade 2) and moderate (grade 3) degenerative changes. This simple procedure provides lasting pain relief, corrects adduction contracture and restores grip and pinch strength, giving good results with few complications.

Fractures of the distal femur treated with the AO dynamic condylar screw.

We report the results of treatment with the dynamic condylar screw of 21 cases of supracondylar and intercondylar fractures of the femur in patients aged 22 to 91 years. There were two nonunions and no deaths. We found the device easy to use and the good fixation allowed early patient mobilisation.

First metacarpal osteotomy for carpo-metacarpal osteoarthritis.

The results of basal osteotomy of the first metacarpal in the treatment of carpo-metacarpal osteoarthritis have been analysed from two small studies, one retrospective and one prospective. Assessment included clinical examination, standardised radiography and computerised pinch-grip analysis. Surgery reduces the subluxation at the first metacarpal base and provides good pain relief and restoration of function in the majority of cases. It is concluded that this relatively simple technique produces very good results without reducing power grip.

The Herbert screw for delayed and non-union of scaphoid fractures: a review of fifty cases.

The results of treatment using the Herbert screw in 50 consecutive patients with delayed or established non-union of the scaphoid are reported. 14% of these fractures failed to unite after operation and a further 20% required prolonged protection, uniting within six months. There were significant technical problems in 28% of operations. A bone graft was only used when there was significant collapse of the scaphoid (52%) and the cases without graft did just as well. Overall, the results do not support the view that this method of treatment is a significant advance over Russe grafting in terms of union rates, but confirm that it produces similar results without the need for prolonged immobilisation and without the need for bone grafting in almost half the cases, although there can be significant technical problems with the procedure.

Silastic ball spacer arthroplasty in the management of hallux valgus and hallux rigidus.

Sixty-two feet in 39 patients who were treated by insertion of a silastic ball spacer prosthesis into the first metatarsophalangeal joint for hallux valgus or hallux rigidus have been reviewed with a follow-up time of between 2 and 6 years. Twenty-one results (34%) were excellent, 27 (43%) were fair, 13 (21%) were poor, and one was revised. Seventeen feet (27%) had some metatarsalgia at followup. Results were disappointing in the young patients; in 19 cases of hallux valgus under the age of 45, 8 were either poor or had been revised. The original concept of the silastic ball spacer was to maintain great toe length and prevent proximal migration of the sesamoids. However 60% of these feet showed settling of the prosthesis or new bone formation around the prosthesis and 54% had more than 2 mm proximal migration of the sesamoid bones. The symptomatic results in these patients were similar to those in whom great toe length had been successfully maintained. The silastic ball spacer infrequently achieves its aims, however maintenance of hallux length does not seem to be important in the symptomatic result.

Mallet thumb.

The uncommon injury of mallet thumb is described, with four case reports. In diagnosis the condition must be distinguished from dropped thumb. Operative treatment is advised which, in this small series, gave excellent results.

Cast-bracing for fractures of the femoral shaft. A biomechanical and clinical study.

A study was made of the mechanics of blood-bearing in a series of patients treated with a cast-brace for fracture of the distal femur. Knee hinges incorporating strain-gauges, a simple force-plate on the floor and a standardised weight-bearing test were used to record axial loads through the cast-brace itself and through the fracture during the phases of healing. The cast-brace carried loads of only 10 to 20 per cent of body weight and functioned mainly as an antibuckling hinged tube. Patterns of weight-bearing recovery showed that the fracture itself limited loads to safe levels. A measure of the recovery of strength at the fracture was determined and termed the "fracture load index". Graphs obtained in this way demonstrated four biomechanical phases of bony union which correlated well with the stages of clinical healing. The clinical application of these results have led to improvements in the design of braces and the use of a cylinder cast-brace for fractures of the distal half of the femoral shaft and of a new type of brace with a hinge at the hip attached to the thigh cast for fractures of the proximal shaft. A simple clinical test is described by which it is possible to monitor the healing of fractures in cast-braces.

A comparative study of methods for treating fractures of the distal half of the femur.

A comparative study of methods for treating fractures of the distal half of the femur was carried out prospectively in the five-year period January 1973 to December 1977. The three methods compared were conservative treatment on a Thomas' splint, application of a knee-hinged cast-brace at five to seven weeks, and intramedullary nailing. The time in bed, in hospital and to union were compared as was the rate of functional recovery of the knee. It is concluded that the cast-brace provides a safe reliable method of treatment, combining the advantages of non-operative management with the early mobilisation possible with intramedullary fixation but without the disadvantages of surgical treatment.

New casting material and improved functional design for lower femoral fracture bracing.

A new water setting light plastic plaster material, Crystona, is presented and its plaster room characteristics compared with plaster of Paris. Plaster of Paris is considered better as the "acute fracture splinting material" in the Accident Service setting. Crystona, however, has considerable advantages as the "dynamic bracing material" in the post-acute fracture period and is demonstrated in the functional bracing of femoral shaft fractures. An improved functional cast brace design is presented, the "Knee Hinge Cylinder Brace" with a simple waist belt suspension to a hinged tube cast without the foot in the treatment of distal half femoral fractures. Using Crystona and the cylinder brace design, the cast weight has been reduced by half and the functional limb bracing improved with free mobilization of the knee, ankle and foot. The prescription, application technique and early clinical experiences are presented.

Hip hinge thigh brace for early mobilization of proximal femoral shaft fractures.

A new design, the 'Hip Hinge Thigh Brace' is presented for the safe early functional mobilization of patients with proximal half femoral shaft fractures. The mechanics, prescription, application technique and early clinical experience are reported. Use of the newer Crystona plastic plaster is shown to provide a more functional brace than the plaster of Paris casts.

A biomechanical study of the effects of growth hormone in experimental fracture healing.

In 65 mature Wistar rats a Kirschner wire was introduced into the medullary cavity of each femur. A closed transverse mid-shaft fracture of one femur was produced by a three-point bending technique. Subsequently the mechanical characteristics of the healing fracture, including the torque and angle of twist required to take the callus to its yield point and to ultimate failure, were compared with those for the opposite femur of each rat. Controls were killed in groups at two, three, four, five and seven weeks. Test animals were given bovine growth hormone in a daily dose of five milligrams before being killed in groups at two, three and four weeks. A significant increase in torque index was found in the two-week group of test animals but not in subsequent groups. No evidence was found that growth hormone given alone could produce an overall shortening of the healing time in fresh fractures.

Enzyme activity, acidic nuclear proteins, and prognosis in human breast cancer.

The activities of the enzymes lactate dehydrogenase, 6-phosphogluconate dehydrogenase, and phosphohexose isomerase in primary human breast cancer biopsies are shown to be related to the time between mastectomy and recurrence of the cancer. These enzymes have higher activity in malignant breast tissues generally than in non-malignant breast tissues. In tumours from patients with long free periods these differences are not apparent.Evidence is presented which suggests that two different types of breast cancer can be distinguished according to the relative amounts of phosphohexose isomerase and acidic nuclear proteins. It is suggested that this difference may be related to hormone responsiveness.