Patients experienced significant post-THR improvements in Harris Hip scores , but this did not differ between impact types .
Recipients of cross-linked vs. conventional polyethylene cup liners experienced reduced femoral head penetration and revision .
There was no impact of femoral stem fixation and cup shell design on implant survival rates .
Evidence on mortality and complications ( aseptic loosening , femoral fracture ) was inconclusive .
BACKGROUND Evolvements in the design , fixation methods , size , and bearing surface of implants for  total hip replacement ( THR ) have led to a variety of options for healthcare professionals to consider .
The need to determine the most optimal combinations of THR implant is warranted .
This systematic review evaluated the clinical effectiveness of different types of THR used for the treatment of end stage arthritis of the hip .
Challenges in evaluating surgical innovation
Research on surgical interventions is associated with several method ological and practical challenges of which few , if any , apply only to surgery . However ,  surgical evaluation  is especially dem and ing because many of these challenges coincide . In this report , the second of three on surgical innovation and evaluation , we discuss obstacles related to the study design of r and omised controlled trials and non-r and omised studies assessing surgical interventions . We also describe the issues related to the nature of surgical procedures -for example , their complexity , surgeon-related factors , and the range of outcomes . Although difficult , surgical evaluation is achievable and necessary . Solutions tailored to surgical research and a framework for generating evidence on which to base surgical practice are essential
Patients experienced significant post-THR improvements in Harris Hip scores , but this did not differ between impact types .
Recipients of cross-linked vs. conventional polyethylene cup liners experienced reduced femoral head penetration and revision .
There was no impact of femoral stem fixation and cup shell design on implant survival rates .
Evidence on mortality and complications ( aseptic loosening , femoral fracture ) was inconclusive .
BACKGROUND Evolvements in the design , fixation methods , size , and bearing surface of implants for  total hip replacement ( THR ) have led to a variety of options for healthcare professionals to consider .
The need to determine the most optimal combinations of THR implant is warranted .
This systematic review evaluated the clinical effectiveness of different types of THR used for the treatment of end stage arthritis of the hip .