Long-term results of the custom- made hip endoprostheses Evolution K® and Adaptiva®: A prospective cohort study.

The aim of our study is to evaluate clinical long-term results and determine changes in periprosthetic bone density of the custom-made hip prostheses Evolution-K and Adaptiva . Periprosthetic bone density were evaluated by means of DEXA (LunariDXA- Prodigy bone densitometer) with a long-term follow-up of 16 (15-18) years (Evolution-K) in 24 patients and 13 (13-15) years (Adaptiva) in 41 patients. Evolution- K had a survival rate of 92% and yielded 79/100 points in Harris Hip Score, a mediocre result. Adaptiva had a survival rate of 99% and achieved a good score of 88/100 points. Bone density measurements demonstrated the greatest loss of bone density in the proximal regions of interest (ROI) for both prosthesis types (Evolution-K: -25.8% ROI 1, -40.3% ROI 7; -8.3% ROI 2, -10.4% ROI 6; Adaptiva: -29.8% ROI 7, -6.8% ROI 6, +14.3% ROI 3, +3.1% ROI 4). Adaptiva yielded a good clinical result as compared to Evolution-K with only average clinical results. Both prostheses clearly showed signs of "stress shielding". Here, the Adaptiva achieved reduced bone density loss as compared to the Evolution-K.