Abstract
The purpose of this study was to analyse and to recommend solutions for early complications with a new total knee mobile bearing device, that promises a logical synthesis of combined A/P translation and rotation ability, but has shown early surgical technique related complications.
Materials and Methods: There were 244 Low Contact Stress (LCS) A/P glide total knee replacements (TKA) performed in the time between 1995 and 1999. Mean age was 67.2 years (range: 53-83). Mean follow-up was 16.5 months (range: 1-51). There was an unusual high incidence of anterior knee pain in this group compared with excellent results utilising rotating platform LCS TKA in this centre. Diagnostic evaluation included radiographs, arthroscopical evaluation, and positron emission tomography in five selected cases.
Results: There were 11 (4.5%) cases with Hoffa fatpad impingement, progressive ligament instability in 5 (2.0%) cases, arthrofibrosis in 4 (1.6%) cases, one malposition of tibial component, and one proximal tibial AVN. Five PET 18F-FDG scans prior to revision surgery revealed increased up-take correlated with intraoperative findings of fatpad fibrosis and/or necrosis.
Conclusion: The LCS A/P glide mobile bearing TKA has theoretical advantages over both meniscal and rotating mobile bearing knee designs. Early occurrence of Hoffa fatpad impingement was caused by surgical mal-technique in this centre that usually retains the vast majority of the fat pad. Revision surgery revealed evidence of impingement and all cases revealed clinical improved after partial excision of the fatpad. We, therefore, recommend partial to total excision of the Hoffa fat pad for utilisation of the A/P glide prosthesis.
The abstracts were prepared by Nico Verdonschot. Correspondence should be addressed to him at Orthopaedic Research Laboratory, University Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
