Comparison of Acetabular Shell Position Using Patient Specific Instruments vs. Standard Surgical Instruments: A Randomized Clinical Trial

Total hip arthroplasty (THA) survivorship relies largely upon appropriate acetabular cup placement. The purpose of this prospective randomized controlled trial was to determine whether the use of a preoperative 3D planning software in combination with patient specific instrumentation (PSI) results in improved cup placement compared with traditional techniques. Thirty-six THA patients were randomized into standard (STD) or PSI technique. Standard approach was completed using traditional techniques, while PSI cases were planned and customized surgical instruments were manufactured. Postoperative CT scans were used to compare planned to actual results. Differences found between planned and actual anteversion were −0.2° ± 6.9° (PSI) and −6.9° ± 8.9° (STD) (P = 0.018). Use of 3D preoperative planning along with PSIs resulted in significantly greater anteversion accuracy than traditional planning and instrumentation.