Despite excellent long-term outcomes, posterior stabilisation by a third condyle continues to receive unwarranted criticism regarding patellar complications and instability.
Complication rates with a tri-condylar posterior-stabilised implant are similar to those with other posterior-stabilised prostheses and have diminished over time due to improvements in prosthesis design.
Material and methods
Post-operative complications and revision rates were assessed retrospectively in a prospective cohort of 4189 consecutive patients who had primary total knee arthroplasty (TKA) using a tri-condylar posterior-stabilised implant (Wright-Tornier) and were then followed-up for at least 24 months. The analysis included 2844 knees. The prosthesis generations were HLS1®, n=20; HLS2®, n=220; HLS Evolution®, n=636; HLS Noetos®, n=1373; and HLS KneeTec®, n=595. Complications were compared across generations by applying Fisher's exact test, and survival was compared using the Kaplan-Meier method.
At last follow-up, there had been 341 (12%) post-operative complications in 306 (10.8%) knees, including 168 (5.9%) related to the implant, 41 (1.4%) infections, and 132 (4.6%) secondary complications unrelated to the implant. Re-operation was required for 200 complications (7%), including 87 (3.1%) consisting in revision of the prosthesis. Implant-related complications were stiffness (n=67, 2.4%), patellar fracture (n=34, 1.2%), patellar clunk syndrome (n=25, 0.9%), patellar loosening (n=3, 0.1%), tibial/femoral loosening (n=15, 0.5%), polyethylene wear (n=3, 0.1%), and implant rupture (n=1, 0.04%). Significant differences across generations were found for stiffness (P<0.0001), patellar fracture (P=0.03), clunk syndrome (P=0.03), and polyethylene wear (P=0.004), whose frequencies declined from one generation to the next. Overall 10-year survival was 92% with no significant difference across generations (P=0.1).
Outcomes of tri-condylar posterior-stabilised TKA are similar to those obtained using other posterior-stabilised implants. Neither patellar complications nor instability are more common, and improvements in implant design have contributed to correct early flaws.
Level of evidence
IV, historical cohort, retrospective assessment of prospectively collected data.Le texte complet de cet article est disponible en PDF.
Keywords : Total knee arthroplasty, Complications, Posterior stabilisation, Third midline condyle, Implant design