Which prosthetic system restores hip biomechanics more effectively? Comparison among three systems

Background: The aim of this paper was to compare ability to restore hip biomechanics among short-stem prosthesis (SSP; MiniHip® Corin, UK), cementless total hip arthroplasty (CTHA; Corail® De Puy, USA) and resurfacing prosthesis (RP; Durom® Zimmer, USA). Methods: One hundred and twenty-four patients with a mean age of 52 yr (26–65 yr) operated on for osteoarthritis were retrospectively studied. There were three groups: SSP n=36, CTHA n=46, and RP n=42. Center of rotation, lateralization, and leg-length discrepancy were evaluated on radiographs and compared to the contralateral healthy (or Tönnis 0 or 1) hips. Results: The center of rotation was equally accurate for the three implants evaluated, but the SSP controlled leg-length discrepancy better than the other two implants; 1.2 mm (−4.7-7 mm) compared with 2.3 mm (−6-7.4 mm) for the CTHA and -2.1 mm (−15-8) for the RP (P=0.001). The mean offset discrepancy in the CTHA group was only 0.6 mm (−7-7) compared with 4.5 mm (−4-7) in SSP and −3.9 (−15-8) in the RP group (P=0.003). The offset was more accurately controlled with the CTHA than the rest of the implants (1.7 mm instead of 3.5 [SSP] and -3.9 [RP] [P=0.0038]). Leg-length accuracy within ±5 mm was obtained in 94% of the hips for SSP, 87% for CTHA, and 67% for RP (P=0.003). Conclusions: Restoration of the center of rotation was equally precise with the three analyzed systems. Considering the contralateral healthy hip, SSP restored more favorably limb length, and offset was more accurately restored with CTHA.