ASEPTIC COMPLICATIONS OF MILLER-GALANTE TOTAL KNEE ARTHROPLASTY AT MORE THAN SIX YEARS FOLLOW-UP

Abstract

Purpose: We report aseptic complications observed in a retrospective series of 130 total knee arthroplasties using first generation Miller-Galante implants at 6.6 months mean follow-up.

Material and methods: Mean age of the patients at surgery was 65.4 years (35–82). One third of the patients was considered to be obese (BI > 30). The principal cause was primary degenerative joint disease (85%). Most of the implants were implanted without cement except for the first 9 prostheses (hybrid). Mean IKS score was 47.3 (12–70) preoperatively and 74.3 (30–99.5) postoperatively with 70% excellent or good results.

Results: The principal aseptic complications in this series were related to the patella (17%): loosening, fracture, dislocation, necrosis and metallosis. These complications were sometimes associated. Use of a metal-backed patellar insert was correlated with the development of certain patellar complications. The rate of aseptic loosening was 3.4% for the tibia, 1.7% for the femur. There was no statistically significant factor predictive of loosening (alignment, laxity, wear were not significant). Wear of the tibial component polyethylene predominated in the medial femorotibial compartment and was strongly correlated with varus and/or frontal laxity (p = 0.01). Images of bone rarefaction in the distal femur were observed in 61% of the cases. Their intensity was variable; stress shielding or osteolytic mechanisms appeared to be involved. Three revision procedures were required to treated clinically invalidating instability: one frontal laxity corrected by implantation of a thicker polyethylene tibial insert and two important sagittal laxities treated by posterior stabilised prostheses. Other aseptic complications were: stiffness requiring arthrolysis (n=1), unexplained painful prosthesis (n=1) and reflex dystrophy (n=1). These complications led to revision in 15% of the cases. Patient characteristics and mode of fixation were similar in patients with and without complications.

Discussion: These observations point out the multifactorial nature of failure of total knee arthroplasty, most often related to a complication of technical errors and implant properties. Nevertheless, patella-related complications was just one of the principal causes of the problems encountered with the Miller-Galante first-generation prosthesis, particularly the metal-backed insert, leading several teams to abandon this implant.