NCT01512550

Importance of Restoring Biomechanical Correct Hip Anatomy During Total Hip Arthroplasty

Evaluation of the Importance in Restoring Biomechanical Correct Hip Anatomy During THA. A Prospective, Randomized and Controlled Study Evaluated by RSA, CT and Gait Analysis

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 75 (actual)
• Sponsor: Region Skane · Academic / Other
• Sex: All
• Age: 40 Years – 75 Years
• Healthy volunteers: Not accepted

Summary

The purpose of this prospective, randomized study is to evaluate the importance of restoring the exact individual hip biomechanics during total hip arthroplasty.

Detailed description

This prospective, controlled and randomized study aims at evaluating the correlation between postoperative hip prosthesis migration and the achieved exactness of biomechanical restoration of hip mechanics during total hip arthroplasty (THA). The main objective is to find out how close the result from the surgery can come to a preferred prosthesis position and whether this makes any difference in terms of loosening, functionality and quality of life for the patient. The prosthesis positioning is performed with either (1) computer assisted navigation, (2) instrumented hip guide measuring devise alignment technique or (3) conventional non-instrumented measuring technique. The ABG II stem system (Stryker) will be used in the modular version for group 1 and 2 and the non-modular version in group 3. Before each operation the investigators will perform exact measurements of anatomical variables using preoperative radiographs (maximum 8 weeks old) and computed tomography images (CT)(taken 3-4 weeks preoperatively). While applying these measurements the investigators will try to preserve the patient´s individual biomechanical situation, most often as compared to the healthy contralateral hip. The variables to be analysed are anteversion of the femoral neck, offset and leg length. This preoperative hip analysis combined with the use of a templating system will give the data needed for component choice and exact positioning of the ABG II hip prosthesis. 75 patients will be randomized into the three groups (25+25+25). The patients will be followed with RadioStereometric Analysis (RSA) for two years (directly postoperatively, 14 days, 3 months, 1 year and 2 years). There will be a second CT scan 1 year postoperatively to measure the actual achieved position. In completion hip specific and general health questionnaires will be used to evaluate patient satisfaction and outcome. All patients will be subject to 3-Dimensional (3-D) gait analysis 3-4 weeks prior to surgery and after one year. The results of the gait analysis will be correlated to the achieved restoration of the hip anatomy and biomechanics. The investigators aim is to improve the fundamental understanding of the hip biomechanics in patients undergoing THA. Will physical performance improve when the individual hip biomechanics is better restored, and in which way and to what extent?

Conditions

• Osteoarthritis

Interventions

Type	Name	Description
PROCEDURE	GF hip guide	Using GF hip guide to measure and control the peroperative positioning of the hip stem
PROCEDURE	Stryker Navigation System	Using Orthomap Modular Hip Software to navigate the operation
DEVICE	ABG II modular femoral component	A hip prosthesis made by Stryker. It has the same basic shape as the ABG II femoral component but has a modular neck system allowing it to better follow the patient specific hip anatomy regarding offset, varus-valgus angle and rotation in the anteroposterior plane.

Timeline

• Start date: 2010-01-01
• Primary completion: 2011-12-01
• Completion: 2017-09-01
• First posted: 2012-01-19
• Last updated: 2017-09-28

Locations

1 site across 1 country: Sweden