This study was carried out to evaluate the impact of Socio-Economic Status (SES) and the influence of geographic access to health services on the possible outcomes of total knee replacement (TKR).

Data on 345 patients with one year follow-up were collected from the database of the orthopaedic department. TKR outcomes were assessed according to Knee Society Score (KSS). A postcode was assigned to each patient depending on the residential area and data from the last census was used to calculate Scottish Index of Multiple Deprivation Score (SIMD) and its rating score for geographic access to health services.

The results show that the SES and the geographic access to medical services have significant impact on Function Scores but do not influence Knee Scores.

Patients living in the least deprived regions had a better post-operative Function Scores compared to those living in more deprived regions with differences of up to 13 points between groups (p< 0.001). Similarly the improvement in Function Scores was dependant on deprivation score. (p=0.015). Pre-operative Knee Score, post-operative Knee Score and improvement in Knee Scores were not influenced by deprivation score.

Patients living in rural regions had better post-operative Function Scores and greater improvements in Function Score compared to urban dweller patients (p≤0.011) with differences of up to 17 points. The Knee Score was not influenced by these variables.

These results suggest that SES and the region of residence should be considered when assessing the outcomes of TKR.

The aim of this study is to identify the incidence of mal-rotation of TKR components in a group of patients with unexplained knee pain identified from the University of Dundee joint replacement database and compare that group with a group of painless TKRs

38 of 45 NexGen LPS Total Knee Replacements identified with unexplained pain at a minimum of 1 year following surgery underwent CT scanning to determine rotational alignment. All patients had a Knee Society Pain score of 20 points or less and a mean Visual Analogue Pain Score of greater than 4.0. This group was compared with a control group of 26 TKRs all of which had never reported pain from 1 year post surgery.

In the painful group mean femoral component rotation was 2.2° of internal rotation (range 8.8°IR to 3.9°ER, sd 3.6, SEm 0.59) compared to 0.9°IR (range 6.9°IR to 6.8°ER, sd 3.39, SEm 0.67) in the painless group (p= 0.15). In the painful group 21.6% of femoral components were more than 6° internally rotated compared with 7.7% in the painless group however this was not statistically significant (p=0.18). No femoral components in either group were in excessive (over 8 degrees) ER.

Tibial component rotation was much more variable than femoral component rotation in both groups particularly in the painful group. Mean tibial component rotation was 4.1°IR (range 37.9°IR to 31.1°ER, sd 14.6, SEm 2.4) in the painful group compared to 2.2°ER (range 8.5°IR to 18.2°ER, sd 6.95, SEm 1.36) in the painless group (p=0.024). 15 tibial components (39.5%) were greater than 10° internally rotated in the painful group whilst no tibial components were more than 10° internally rotated in the pain free group (p< 0.001). In the painful group 7 tibial components (18.4%) were more than 10° externally rotated whilst 4 (15.4%) were in more than 10° ER in the painless group (p=1.00). Overall 22 tibial components (57.9%) were in more than 10° of malrotation in the painful group compared with 4 (15.4%) in the pain free group (p=0.05).

Mean rotational mismatch between femoral and tibial components was 1.9° tibial IR (range 39.7° tibial IR to 35.1° tibial ER, sd 16.1, SEm 2.7) in the painful group whilst in the painless group mean rotational mismatch was 3.1 degrees tibial ER (range 10.3° tibial IR to 22.1° tibial ER, sd 8.4, SEm 1.65). This difference was not significant (p=0.12). 16 TKRs (55.3%) had rotational mismatch of more than 10° in the painful group compared to 7 (26.9%) in the control group (p=0.02).

We conclude that rotational malalignment is frequent in painful total knee replacements and may be a major cause of pain after TKR. In particular tibial internal rotation is the most frequent alignment error in the painful TKR and appears to play a major role in the aetiology of pain after TKR.

Pre- and post-operative Knee Society Scores for 2105 Total Knee Replacements (TKRs) with minimum three year follow-up were evaluated. The effect of gender, age at operation and BMI at operation on Knee Society Data at pre-operative review, at one year post-operatively and at three years after TKR was analysed.

Total Knee Score pre-operatively, and at both one year and three year review was found to be independent of gender, age and BMI. There was no effect of the three demographic variables on the component scores for pain, range of motion, stability, alignment, extensor lag and flexion contracture.

Lower Function Scores were associated with female gender (p< 0.001), age greater than 70 at time of operation (p≤0.004) and obesity (p< 0.001). Median Function Scores were consistently higher in males than females by 5 points pre- and post-operatively (p< 0.001). At three years post-operatively, the median Function Score in the 80 and over age group was lower than all other age groups (p< 0.001), by between 15 and 20 points. Whilst the normal and overweight groups had similar Function Scores the class I obese and class II obese groups consistently had lower median Function Scores by 5 (p< 0.001) and 10 points (p< 0.001) respectively.

We conclude that whilst the Knee Score and its component scores are independent of gender, age and BMI, all three of these demographic variables can be associated with significant differences in Function Score.

Surgical site infection (SSI) is an important outcome indicator. It is estimated that 70% of post-operative infections present after discharge. A reliable post-discharge surveillance (PDS) method is yet to be described. The aim of this prospective cohort study was to assess the reliability of patient self-diagnosis. Telephone questionnaires were used following hip and knee prosthetic surgery. A trained validation nurse checked the wounds of all patients reporting problems and a sample of those who did not. 376 elective hip and knee arthroplasty procedures from 363 patients were included. In-patient infection rate was 3.1% (13 of 422 procedures) and post-discharge infection rate was 5.2% (22 of 422 procedures). Results suggest that patients can reliably self diagnose SSI. The sensitivity of the procedure (the probability that the telephone surveillance will detect an infection given that the patients has an infection) was 90.9%. The specificity (the probability that the telephone surveillance will report no infection given that no infection is present) was 76.6%. Hence telephone PDS of SSI is a valuable means of identifying accurate rates of hospital acquired infection following surgery. In this study population, 41% of infections were diagnosed post discharge, which is lower than has previously been estimated. PDS of SSI is necessary if accurate rates of hospital acquired infection following surgery are to be available.

As part of a user group of a collarless polished tapered stem a database was established in 1993 recording all significant data pre-operatively, intra-operatively and at 1,3,5 and 7 years.

All were primary hip replacements and the study included 38 different surgeons who were free to use the head size, approach and cup of their choosing. All hips had a collarless polished tapered prosthesis (Zimmer inc.).

Data on 2,250 hips were available for analysis and stratification of risk factors for dislocation. Correlation of head size and surgical approach was performed and tested for significance. The patient demographics were standard for a typical arthroplasty study group. Of the surgical approaches used, 13.1% were anterolateral, 27.55% lateral, 23.88% posterior and 35.47% Hardinge. There were no trochanter osteotomies or anterior approaches.

94 (100%) of the hips had a first dislocation occurring in the first two years: 38 during acute stay (40.43%), 45 from acute stay to the first year (47.88%) and 11 during the second year (11.7%). The 22mm head was associated with the greatest risk of dislocation (5.93%, P < 0.001). The risks with the 28mm head (3.05%) and the 26mm head (2.5%) were not significantly different. The lowest risk of dislocation occurred with the lateral approach (2.11%) and the highest with the posterior approach (5.99%). Dislocation rates for the anterolateral and Hardinge approaches (4.1% and 3.28% respectively) were not significantly different. Unfortunately data pertaining to frequency of capsular repair combined with the posterior approach was not available.

The combination of lateral approach and 28mm head was associated with the lowest dislocation risk of 1.56%, while the risk with the posterior approach and 22mm head was the highest at 10.09%.

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

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.

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.