Total knee arthoplasty (TKA) remains a standard treatment for advanced knee arthritis. The aim of the procedure is to restore function and relieve pain ideally for the rest of patient's life. Patient matched templating (PMT) or patient specific instrumentation (PSI) is a recent development for alignment of TKA components that uses disposable guides. The users of PSI claim it to be the optimum balance of new technology and conventional technique by reducing the complexity of conventional alignment and sizing tools.

To assess the clinical and radiological outcome of Primary TKA done with PSI.

More than 200 cases of TKA have been done in our unit using PSI and we analysed the radiographic outcome of these cases postoperatively. We also reviewed the clinical outcome of 103 patients with 1 year and 43 patients with 2 year follow-up. Data was collected prospectively: pre-operatively and at 1 year and 2 years post-operatively including Oxford knee score (OKS), WOMAC and American knee society score (AKS). Standard AP and lateral films were done pre-operatively and post-operatively.

Mean age was 66 years. There were 56 female and 47 male patients. Mean post-operative angles on standard films were: Alpha = 95.6, Beta = 88.4, Saggittal femur = 3.4 and Saggittal tibia = 90.8. Of the 103 cases with 1 year follow-up, there was significant improvement in all clinical outcome scores. Mean OKS improved from 18 to 39 at 1 year and remained the same at 2 years, WOMAC improved from 40 to 18 in both 1 and 2 years post-op. AKS Total improved from 79 to 173 at 1 year and 170 at 2 years.

Performing TKA using PSI is safe and provides good radiological alignment in the coronal and sagittal plane. Significant improvement in outcome scores were seen at one and two year follow up and reached levels that compared favourably with other reported series of TKA outcome from our unit.

It has been reported that some of the local anaesthetic agents possess antimicrobial activity against clinically-significant bacteria. Although bupivacaine exhibits a bacteriostatic effect at concentrations above 0.25% there are concerns that it might interact with some of the other antibiotics administered to patients. Whilst these interactions may be potentially benign, the risk is that they are antagonistic and that local bupivacaine might predispose the patient to a higher risk of infection.

Bupivacaine is commonly administered as a local anaesthetic following knee arthroplasy; the purpose of this study was to assess its potential interactions with gentamicin eluting from the cement used to fix the device.

A strain of Saphylococcus aureus (29213) with established susceptible Minimal Inhibition Concentration (MIC) and Minimal Bactericidal Concentration (MBC) for gentamicin was used. This organism was inoculated into four types of broth; Mueller-Hinton broth (MH), MH with different concentrations of gentamicin, MH with 0.25% and 0.125% bupivacaine and MH with various combinations of gentamicin and bupivacaine. The broths were incubated at 37C and at 0.5, 1, 2, 3, 6 and 24 hours post inoculation the number of bacteria remaining were counted. From these data kill-curves were generated describing the absolute and individual rates of killing seen with bupivacaine and gentamicin alone and when in combination.

Bupivacaine showed a bacteriostatic effect only at concentrations of 0.25% and higher. All concentrations of gentamicin above or equal to the expected MBC showed bactericidal effect. However, in combination with both strengths of Bupivacaine (0.25 and 0.125%) the bacteriocidal effect of gentamicin was seen at a lower concentration and the rate of killing of bacteria was enhanced.

Bupivacaine has bacteriostatic effect at concentrations above 0.25% in line with published data. In these experiments we have shown that the use of bupivacaine together with gentamicin does not reduce the bactericidal property of the antibiotic and that the bactericidal effect of gentamicin appears to be enhanced by bupivacaine. This would suggest that the local use of bupivacaine is unlikely to increase the risk of infection in patients undergoing knee arthroplasty and may actually be beneficial.

This is a prospective review of consecutive patients who underwent knee revision surgery using the Legion knee system.

Clinical and functional assessments (American Knee Scores-AKS, WOMAC and Oxford knee score-OKS) were carried out preoperatively, one year and 2 years post op. Radiographic evaluation was done at 1 and 2 years included review of standing AP, lateral and skyline views. Figgie's method was used to measure the joint line reproduction.

210 patients underwent revision knee system 103 male: 107 females with a mean age of 66.4 (44–87) yrs. Mean BMI-26.03 (21–50). We had a 2-year follow up for 110 patients. Surgery was carried out at a single centre and performed by Bristol knee specialists.

Indications for surgery were aseptic loosening (84), infection (27) instability (47), pain and stiffness (31), progression of disease (6), peri-prosthetic fractures (15)

The AKS and WOMAC scores at, 1 year and 2 years follow up showed significant improvements in pain and function. The mean total AKS improved from 75.7/200 pre-operatively to 140.5/200 at 2 yrs. Radiographic assessment showed a mean AP coronal femoral angle of 95.3 degrees (89.6–99.9), coronal tibial angle of 90.1 degrees (88–92). The mean sagittal femoral and tibial angles were 88.4 and 90.4 degrees respectively.

The short-term results showed significant improvement in functional and pain scores irrespective of indications for revision surgery. The Legion system has showed good outcome scores that match or beat published series on revisions. It also showed a good ability to restore joint line.