Peri-prosthetic infection is amongst the most
common causes of failure following total knee replacement (TKR).
In the presence of established infection, thorough joint debridement
and removal of all components is necessary following which new components
may be implanted. This can be performed in one or two stages; two-stage revision
with placement of an interim antibiotic-loaded spacer is regarded
by many to be the standard procedure for eradication of peri-prosthetic
joint infection. We present our experience of a consecutive series of 50 single-stage
revision TKRs for established deep infection performed between 1979
and 2010. There were 33 women and 17 men with a mean age at revision
of 66.8 years (42 to 84) and a mean follow-up of 10.5 years (2 to
24). The mean time between the primary TKR and the revision procedure
was 2.05 years (1 to 8). Only one patient required a further revision for recurrent infection,
representing a success rate of 98%. Nine patients required further
revision for aseptic loosening, according to microbiological testing
of biopsies taken at the subsequent surgery. Three other patients
developed a further septic episode but none required another revision. These results suggest that a single-stage revision can produce
comparable results to a two-stage revision. Single-stage revision
offers a reduction in costs as well as less morbidity and inconvenience
for patients. Cite this article:
We describe the survivorship of the Medial Rotation total knee replacement (TKR) at ten years in 228 cemented primary replacements implanted between October 1994 and October 2006, with their clinical and radiological outcome. This implant has a highly congruent medial compartment, with the femoral component represented by a portion of a sphere which articulates with a matched concave surface on the medial side of the tibial insert. There were 78 men (17 bilateral TKRs) and 111 women (22 bilateral TKRs) with a mean age of 67.9 years (28 to 90). All the patients were assessed clinically and radiologically using the American Knee Society scoring systems. The mean follow-up was for six years (1 to 13) with only two patients lost to follow-up and 34 dying during the period of study, one of whom had required revision for infection. There were 11 revisions performed in total, three for aseptic loosening, six for infection, one for a periprosthetic fracture and one for a painful but well-fixed replacement performed at another centre. With revision for any cause as the endpoint, the survival at ten years was 94.5% (95% CI 85.1 to 100), and with aseptic loosening as the endpoint 98.4% (95% CI 93 to 100). The mean American Knee Society score improved from 47.6 (0 to 88) to 72.2 (26 to 100) and for function from 45.1 (0 to 100) to 93.1 (45 to 100). Radiological review failed to detect migration in any of the surviving knees. The clinical and radiological results of the Medial Rotation TKR are satisfactory at ten years. The increased congruence of the medial compartment has not led to an increased rate of loosening and continued use can be supported.
We investigated the changes in surface roughness of retrieved femoral components in 18 men and four women at revision knee surgery. The mean age at revision was 68.4 years and the mean period of implantation was for 55.6 months. Eighteen implants were retrieved for aseptic loosening and four for infection. The surface changes in the articulating areas were inspected visually and the roughness (Ra) analysed with a profilometer. Parallel scratching and burnishing were the two main forms of damage. The mean Ra measurements in the articulating areas showed no statistically significant difference when compared with those in a control area on either side of the patellar groove at the apex of the femoral flange. This suggests that it is not essential to revise a well-fixed and correctly aligned femoral component where the polished surface has become burnished or bears fine parallel scratches, if the revision is conducted solely for failure of the tibial component.
We report a ten-year rate of survival of 96% for the cemented Freeman-Samuelson knee arthroplasty in patients from the Swedish Knee Registry and the Royal London Hospital with revision for aseptic loosening as the criterion for failure.
