Abstract
Introduction
The causes of revision total knee replacement are varied. There is a subset of these revision cases (poly wear and some cases of instability for example) where the ability to retain the metal femoral and tibial components and replacing just the polyethylene is an appealing option. We report on a series of RTKR where only the poly insert was replaced and the patients were followed for a minimum of ten years.
Materials and Methods
Our study group consisted of 64 consecutive non infected RTKR patients who underwent a revision of the polyethylene alone between 1998 and 2006. All patients had been treated originally with the same cemented, CR, patella resurfaced primary TKR. Reasons for revision were 51 poly wear and/or osteolysis, 7 instability, and 6 other. The average time from the primary to the revision surgery was 9.1 years (range 2.2 to 16.1 years). All patients had an isolated poly liner change. No femurs or tibial trays were revised. Average age of the cohort at revision was 72.2 (range 48 to 88). Average BMI was 31.9 (range 23.6 to 43.9). There were 36 female patients. Of the group, 42 were ASA 1 or 2 and 22 were ASA 3. Pre-op alignment averaged 6.0 (range 2 varus to 8 valgus). Patients were followed for a minimum of 10 years (range 10 to 19 years).
Results
At final follow up 13 patients had died, none were lost to follow up leaving 51 patients available for review. There were 7 reoperations in 6 patients (7 knees). Reasons for reoperation were: 4 aseptic tibial loosening at an average of 4.1 years (range 1.2 to 8.3) following first poly revision, two for polywear at an average 9 years post first poly revision, and one for deep infection (5.6 years post first poly revision). Knee society scores at 6 weeks post revision was 93.5 (range 38 to 100) and at final follow up for the non-revised knees was 91.6 (range 36 to 100).
Conclusion
In appropriate settings, where the femoral and tibial components are satisfactorily aligned and well fixed and the soft tissues can be balanced, a poly change alone can provide a durable solution for the revision total knee patient. The ability to retain the metal components has advantages in terms of patient morbidity and cost.
