No clinical benefit of titanium nitride coating in cementless mobile-bearing total knee arthroplasty

Titanium nitride (TiN) coating of cobalt-chromium-molybdenum (CoCrMo) implants has shown to improve the biomechanical properties of the implant surface and to reduce adhesive wear in vitro. It is yet unknown whether TiN coating of total knee prosthesis (TKP) affects the postoperative clinical outcome of total knee arthroplasty (TKA). In a double-blind randomized controlled clinical trial, 101 patients received an uncemented mobile-bearing CoCrMo TKP, either TiN coated or uncoated. Primary outcome measure visual analogue scale (VAS) score for pain, and secondary outcome measures Knee Society Score (KSS), revision rate and adverse events, range of motion of the knee as well as knee circumference and knee skin temperature were assessed 6 weeks, 6 months, 1 year and 5 years postoperative. Repeated measures analysis was used to evaluate the postoperative outcome measures over time. There was no difference between the two groups in VAS score, KSS, revision rate, range of motion of the knee, knee circumference and knee skin temperature. There were no adverse events that could be related to the TiN coating. TiN-coated TKP does not influence the postoperative outcome of uncemented mobile-bearing TKA regarding postoperative pain, revision rate, range of motion, swelling and temperature of the knee. Therefore, TiN coating of CoCrMo TKP has no clinical benefit on the outcome of cementless mobile-bearing TKA. Therapeutic study, Level I.