Accuracy of Leg Length and Offset Restoration in Femoral Pinless Navigation Compared to Navigation Using a Fixed Pin during Total Hip Arthroplasty

Abstract EN

Equalization of biomechanical differences is a major goal in total hip arthroplasty (THA).

In the current study we compared the accuracy of restoring leg length and offset using imageless navigation with an osseous fixed pin to a femoral pinless device in 97 minimally invasive THAs through an anterolateral approach in the lateral decubitus position.

Leg length and offset differences were evaluated on magnification-corrected radiographs by a blinded observer.

A postoperative mean difference of -0.9 mm (95% CI -2.8 mm to 1.1 mm, p = 0.38) between pinless navigation and navigation with a fixed pin was observed for leg length and that of -2.4 mm (95% CI -3.9 mm to -0.9 mm, p = 0.002) was observed for offset, respectively.

The number of patients with a residual difference below 5 mm after THA was higher if using a fixed pin than in pinless navigation for both leg length (98.2%, 54/55 to 50.0%, 21/42, p < 0.001) and offset (100.0%, 55/55 to 71.4%, 30/42, p < 0.001).

Imageless navigation is a feasible method in intraoperative control of leg length and offset in minimally invasive THA.

The use of pins fixed to the bone has a higher precision than pinless devices.

This trial is registered with DRKS00000739.