Recent projections expect the number of revision knee replacements performed to grow from 38,000 in 2005 to 270,000 by the year 2030¹. Although the results of primary total knee arthroplasty are well documented, with overall implant survivorship at 15 years greater than 95%² the results of revision procedures are not as well known. What if the revision TKR fails and what is the prevalence of failure of revision TKRs, the complications and re-operation rates? There are various studies which has either exclusively dealt with the causes or outcomes of revision with a particular prosthesis and survivorship analysis. The effectiveness of revision total knee replacement must be considered in the light of complications rates which could be either medical, orthopaedic surgery related complications or combination of both.

The purpose of this study was to evaluate the prevalence of complications, reoperation rates and outcomes in a single surgeon's series between 1984 and 2008.

Ninety nine index revision cases were studied. Incidences of surgical complications were 52.5%. The total reoperation rate was 34.3% whilst single re revision accounted for 19.9% whereas multiple re-revision incidences were 4%. The mean outcome in terms of Knee Society Score, Knee Society Function, and Knee society range of motion was statistically and clinically significant between pre operative and posts operative score at one year and remained consistent with time. These results suggest that modern revision total knee replacement are satisfactory operations and the outcomes perhaps can be improved if relatively simple strategies are followed by focusing these operations to specialized that accumulate enough experience from these demanding surgeries. Overall the results asserts that even in the hands of an experienced surgeon the complications do occur which is usually multi factorial, whilst in the light of complications and reoperation incidence the patients can be counselled thoroughly before the procedure.

This study used CT analysis to determine the rotational alignment of 39 painful and 26 painless fixed-bearing total knee replacements (TKRs) from a cohort of 740 NexGen Legacy posterior-stabilised and cruciate-retaining prostheses implanted between May 1996 and August 2003.

The mean rotation of the tibial component was 4.3° of internal rotation (25.4° internal to 13.9° external rotation) in the painful group and 2.2° of external rotation (8.5° internal to 18.2° external rotation) in the painfree group (p = 0.024). In the painful group 17 tibial components were internally rotated more than 9° compared with none in the painfree group (p < 0.001). Additionally, six femoral components in the painful group were internally rotated more than 6° compared with none in the painfree group (p = 0.017). External rotational errors were not found to be associated with pain.

Overall, 22 (56.4%) of the painful TKRs had internal rotational errors involving the femoral, the tibial or both components. It is estimated that at least 4.6% of all our TKRs have been implanted with significant internal rotational errors.

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.