Introduction: Substantial evidence is now available that complex multi-variate models such as Artificial Neural Networks and Finite Element Analysis can predict bone strength better than DXA. In order to build such models effectively, it is essential to determine which basic individual parameters will be used. The current study attempts to improve a number of existing parameters that reflect bone structure, originating from spectral analysis of cancellous bone in radiographic images, to assess whether their correlation with mechanical strength of bone can be improved.

M& M: Sixty standard AP x-rays of cadaveric human radii, for which mechanical data was available, have been examined. The bones had been mechanically tested to destruction and the details of the test have been published previously. The x-rays were digitized at 160 mm/ pixel, using a dedicated scanner. ROI of 64x64 pixels corresponding to 1x1 cm in the original x-rays were used for the analysis. Low pass and High pass filters were moved stepwise to determine the most effective bandwidth for the identification and measurements of the magnitude peaks in the fast Fourier transform (FFT).

Results: The spectral trabecular index had a correlation with load at fracture (LF) of −0.002 and with the work at fracture (WF) of −0.07. The filtered parameter, termed spectral index of bone structure (SIBS), increased these correlations to 0.41 and 0.46 respectively. The Longitudinal trabecular index had a correlation of 0.09 with LF and 0.04 with WF. The corresponding filtered parameter, termed longitudinal trabecular index of bone structure (LIBS), increased these correlation coefficients to 0.39 with LF and 0.41 with WF. Finally the Transverse trabecular index had a correlation of −0.19 with LF and −0.04 with WF. The Transverse index of bone structure (TIBS) altered the correlations to 0.17 with LF and 0.36 with WF. For this sample size, the 5% significance threshold for correlations is 0.25 and for the 1% level is 0.325.

Discussion: This refinement of the individual spectral parameters is an essential step towards the improvement of multivariate models, leading to a potentially improved assessment of fracture risk. The general assessment of trabeculae and particularly the longitudinal ones was substantially improved by the new method of measurement. These parameters can now be incorporated into more complex models that take into account other characteristics such as age of the patients, cortical thickness and size of the bones and which are knowingly related to bone fragility.

Biomechanical alignment of the knee is a major determinant in the outcome of Total Knee Arthroplasty. However, the best method to assess the alignment is yet undecided. Conventional methods use hip to ankle “long” standing x-rays but these suffer from technical difficulties and hence are a potential for error. Short x-rays are considered to have doubtful accuracy.

This study aimed to assess if the “short” AP x-rays could be used to assess the lower limb axis within a range of statistically insignificant and clinically acceptable difference.

The results indicate the readings from the short x-rays were not statistically different from those obtained from the long x-rays in four sets of observations. The largest difference between any two readings was 0.68 degrees. The analysis of data showed that the measurements from the short x-rays could indeed be used to assess the long axis of the lower limb with the provison that there is no gross femoral shaft deformity.

Radiographs are often used to determine the varus/ valgus alignment of the prosthesis in relation to the long axis of femur. This is usually considered to be one of the important parameters in predicting early mechanical failure of the total hip replacement.

The measurements made by the University of Dundee X-Ray Analysis Software and skilled manual operators of the varus and valgus angulations of hip prosthesis in relation to the femoral shaft were compared for inter and intra-observer reliability.

The manual measurements were carried out on the same randomly selected digitised images of 78 postoperative X-rays by two independent observers and by the same analysis software twice.

The results of the study showed a very high agreement between the readings of the two methods (the largest difference was 0.6 degrees) and two observers (the largest difference being 0.08 degrees) indicating excellent intra and inter observer reliability. The lowest correlation was 0.82 and this was between software reading 1 of observer 1 and software reading 1 of observer 2. The highest correlation of 0.99 was between software reading 1 and software reading 2 for the same observer. The software analysed the x-rays with precision and accuracy and was much faster than manual measurement. A further benefit of the computerised method is an unskilled operator can be trained in 15 minutes to use the software

Introduction: The aims of this paper are to compare the results of Measuring migration rates on radiographs manually and by computer assisted analysis of digitised images.

Methods: Standardised anteroposterior standing hip radiographs taken post operatively and then yearly following hip replacement were used. The radiographs were then scanned at 150 dpi (gray scale) and saved as tif files. The migration was measured manually by drawing a line along the long axis of the femoral component connecting the distal tip, to the notch, which is used to impact the stem proximally. This gives us the length of the hip replacement and an axis along which migration can be measured. The tip of the greater trochanter was selected as a bony landmark. On the plain radiographs two sets of readings were made by one observer. The digitized images were then analysed in the same way using a software package (designed in-house at the University of Dundee). Two sets of readings were performed by observer one and a second set by an independent observer. Statistics: Inter and Intra observer rates were calculated using a paired sample t test.

Results: For the manual readings intra observer mean difference was 0.53mm (Cl 0.31–0.74mm). Comparing manual vs computer readings for observer one there was a correlation of 0.89. For the computer readings intra observer mean difference was 0.36mm (CI 0.64–0.8mm) and inter observer mean difference 0.16 mm, both non-significant differences. This evidence shows that the readings made manually and by computer were not significantly different and that there was no significant inter and intra observer variation. The advantage of computer storage and reading being the faster analysis, the ability to store and access large numbers of radiographs. The disadvantages being the need to scan the radiographs to allow measurement.

Objective: To examine the relationship between three measurements of bone quality and bone strength of the tibial plateau, and the relationships between these measurements. Methods: The bone quality of sixteen cadaveric tibias was assessed for density and architecture using three methods: DXA, pQCT, and spectral analysis of digitised radiographs. These bone quality measurements were correlated with the þxation strength of a bicondylar plateau fracture, obtained by mechanical testing. Results: All three techniques correlate strongly with the mechanical strength of the þxed tibial plateau, with the highest correlation being with DXA (r=0.81, P< 0.001), and pQCT (r=0.79, P< 0.001); followed by spectral analysis (r= 0.5, P,0.01). DXA correlates strongly with pQCT (r=0.95, P< 0.001); Whereas, spectral analysis has a weaker correlation with both DXA (r=0.65, P< 0.01), and pQCT (r=0.69, P< 0.01). Discussion: This is the þrst study of bone quality assessment in the tibial plateau, and as with studies at other sites, DXA showed that BMD has the best correlation with mechanical failure. Both DXA and pQCT are a reßection of density assessment which explains the strong correlation seen. However, the strength of bone is a function of not just quantity and density but also its structure. This was assessed using spectral analysis which involves image processing and pattern recognition algorithm of the trabecular structure. This measures structure only and this may explain the lower correlation with bone strength. Nevertheless we feel that further analysis may demonstrate a speciþc use of this technique to compliment either DXA or PqCT in providing complete assessment of the bone.

Osteoporosis has been implicated as one of the causative factors for Colles’ fracture. The current study was designed to establish whether the degree of osteoporosis has any influence on the radiological severity of Colles’ fracture in active elderly peri-menopausal female patients.

Female peri-menopausal patients who sustained a Colles’ fracture were studied. The ultra distal Bone Mineral Density (uBMD) was determined using DXA in the contralateral non-fractured wrists, which were also x-rayed. Anthropometric measurements were recorded, the radiological severity of the fracture was assessed using a computerised image analysis system, which measured the radial angle, height and width on AP view and the dorsal tilt on lateral view. Measurements were carried out on the fractured and the normal wrist. Pearson’s correlations between age, height, weight, BMI, uBMD and fracture measurements were carried out. The Bone Deformity Index (BDI) was defined as the summation of all the differences of the previous parameters between the normal and fractured wrists on the AP view. ANOVA, with bonferroni correction, was used to compare the parameters and the radiological measurements between normal, osteopenic and osteoporotic patients.

Sixty-seven patients were recruited. Those with Barton fractures, previous fractures of the wrist or a previous history of chronic treatment with bone modifying drugs were excluded. Forty eight patients were analysed. The parameters measured had a tendency to be worse with increasing degree of osteoporosis, although the only significance was in the measurement of dorsal tilt on the lateral view (p = 0.05). The normal patients were significantly heavier (89.3 kg) than the other two groups (p =0.03). In the osteoporotic group the correlation between uBMD and the BDI was −0.6, between uBMD and radial height difference was –0.5 and between uBMD and the angle difference in AP was also –0.5. Similar correlations in normal patients were not statistically significant. Power estimates were performed. Because of the relatively large variability within the samples, a sample size of 550 cases will be necessary to reach a power of 80% to detect a pre-defined clinically significant difference of 3 units in the BDI between groups.

The evidence from this study suggests that the initial radiological deformity in osteoporotic patients was greater in those patients with severe degree of osteoporosis. The deformity in normal patients did not have a correlation with the uBMD but these patients were significantly heavier, indicating a different combination of causative factors in these two groups. The precision of the current method of x-ray measurements has enabled a precise definition of the variability within the different groups, resulting in the production of information that was not previously available.

Introduction: Electronic storage of X-rays is becoming standard. It would therefore, be highly desirable to use a computer as a tool for obtaining useful measurements from radiographs. The current study investigates the reliability of computerised measurements of radiographs of the Souter-Strathclyde elbow.

Materials and Methods: 56 AP radiographs of Souter-Strathclyde Elbows were assessed for the parameters described by Trail et al (1999). The respective x-rays were digitised using a transparency flatbed scanner with a resolution of 80 _m/pixel. The radiographs were then measured for the migration and movement of the prosthesis using the following lines: Hapd1, Hapd2, Hapd3 Hapd4. All the radiographs were measured twice manually with at least one week interval, the observer being blind to the initial results at the time of the second measurement. The x-rays were again measured twice using the computer and a measuring software developed in our own department. The results were analysed for intra observer variability, using paired t-test and Pearson correlations.

Results: Table 1 shows the results of the paired measurements, with the confidence intervals for the mean error, the p for the paired t-test and the correlations between the paired readings. M1 and M2 represent the manual readings, while C1 and C2 the computerised readings.

Conclusions: The mean error of all paired readings was below 1 mm. The correlation between all paired readings was highly significant, with all the paired readings with the computer as a tool being .99. The only difference that was statistically significant was Hapd3M1-M2, between two manual measurements, although the mean error is not clinically relevant, still being less than 1mm. We conclude that computerised measurements of radiographs are at least as reliable as those conducted directly on film.

We developed a new type of bioactive bone cement, CAP (Hydroxyapatite composite resin; composed of 77% w/w hydroxyapatite granules and bisphenol-A glycidyl methacrylate-based resin) for bony defect filling. Elastic modulus of CAP is similar to a cortical bone, while it is injectable before hardening and physiologically bonding with bone in 4 to 8 weeks. We present a new method of treatment for unstable Colles’ fracture with this material in clinical use.

Experimental comminuted Colles’ fracture was produced in three fresh frozen cadavara. Fracture was reduced and fixed percutaneously with K-wires. 4.5mm drill hole was opened on the radial cortex 3cm proximal to the fracture site. Comminuted fragments were pushed-up to the subchondral area with a blunt rod and CAP was injected through the same way. After cement hardening, K-wires were removed. X-ray photos were examined before fracture, after fracture and after reconstruction with CAP, in order to evaluate the shape of the radius. CT was examined to evaluate the placement of CAP.

Radiographic parameters of radii were well recovered after reconstruction with CAP. Over correction of the radial length was observed in one bone but good reduction was generally achieved (Table). This means realignment of the distal radioulnar joint, which results in good outcome clinically. In transverse section of CT, 41 to 69% (average 55%) of subchondral area was filled with CAP. Filling of CAP was better in an osteoporotic bone. These results show the usefulness of this material for treatment of unstable Colles’ fracture especially in osteoporotic patients.

The Souter-Strathclyde total elbow has been used in our unit since 1989. The current study reviews the results of the first 10 years of practice and compares them with reported results. Pain relief, complication rate, functional outcome and patient satisfaction were evaluated.

The primary indication for replacement was pain in the presence of advanced rheumatoid destruction of the joint on radiography, classified according to Souter (1989). Complications had been dealt with as appropriate, reviewed retrospectively and classified according to Dent et al (1995). Pain, activities of daily living and overall satisfaction were assessed by questionnaire. They were measured clinically for range of movement, power, stability and elbow performance using the Mayo Elbow Performance Score. Follow up x-rays were assessed for evidence of loosening. Fifty elbows were replaced in 43 patients, 34 female and nine male. There were 24 right and 26 left elbows. All patients had rheumatoid arthritis; one patient had an associated traumatic injury to the elbow. The pre-operative radiographs available for review were 10 grade 3, 12 grade 4 and 17 grade 5. The mean age of the patients was 65 years (range: 33–83 years). The average follow up was five years (range: 1-10 years). Fourteen patients died and one was lost to follow up, leaving 33 elbows in 28 patients. There were 12 complications, eight were type A, four elbows had a transient radial palsy, three had ulnar neuritis and there was one pressure sore. The only type B complication was a persisting subluxation in extension. There were three type C complications with early revision, a humeral fracture revised to a humeral resection implant, a subluxated joint revised to an ulnar retentive prosthesis and one deep infection revised to an excision arthroplasty. Twenty-four had no pain, six had occasional pain, one got pain with heavy use and two had pain at night. For ADL, two patients could not reach their mouth with difficult feeding and five had trouble toileting. All were able to dress themselves and turn taps. The preoperative range motion was 110° (±23.1°) Flex., 40° (±11.5°) Ext., 45° (±12.2°) Pron., and 46° (±36.9°) Sup. Postoperatively the mean ranges were 131° (±13.1°) Flex., 32° (±16°) Ext., 81° (±14°) Pron. and 72° (±32°) supination. By the Mayo performance score 67% had excellent results, 8% had good results, 17% fair and 8% poor. 67% of patients were extremely pleased with their results and only one was dissatisfied. No elbows had radiological evidence of loosening requiring revision.

There was substantial pain relief and an increase in the range of motion. The number of complications was acceptable and the patient satisfaction level was very high. The Souter-Strathclyde elbow arthroplasty is an appropriate option in rheumatoid patients with elbow destruction.