The effect of femoral offset modification on gait after total hip arthroplasty

Abstract

Background and purposeA decrease of 15% in femoral offset (FO) has been reported to generate a weakness of the abductor muscle, but this has not been directly linked to an alteration of gait. Our hypothesis was that this 15% decrease in FO may also generate a clinically detectable alteration in the gait.Patients and methodsWe performed a prospective comparative study on 28 patients who underwent total hip arthroplasty (THA) for unilateral primary osteoarthritis. The 3D hip anatomy was analyzed preoperatively and postoperatively. 3 groups were defined according to the alteration in FO following surgery: a minimum decrease of 15% (9 patients), restored (14), and a minimum increase of 15% (5). A gait analysis was performed at 1-year follow-up using an ambulatory device. Each limb was compared to the contralateral healthy limb.ResultsIn contrast to the “restored” group and the “increased” group, in the “decreased” group there was a statistically significant asymmetry between sides, with reduced range of motion and a lower maximal swing speed on the operated side.InterpretationA decrease in FO of 15% or more after THA leads to an alteration in the gait. We recommend 3-D preoperative planning because the FO may be underestimated by up to 20% on radiographs and it may therefore not be restored, with clinical consequences.

The impact of standard combined anteversion definitions on gait and clinical outcome within one year after total hip arthroplasty

“…t(0)preoperative, t(1)=6 months after THA, t(2)=12 months after THA; mean (SD) range; significance level for p-value: 5%/3=1.6% increase of HHS, HOOS and EQ-5D within the first year similarly to literature [30,31]. Cup malalignment remains the greatest problem in THA.…”

The Influence of Hip Rotation on Femoral Offset Following Short Stem Total Hip Arthroplasty

“…[1] Femoral offset (FO) has been identified to be a clinically relevant factor for functional outcome and implant survival following THA. [3,4] However, in ssTHA, there is a paucity of knowledge regarding functional implications of FO. [5] Additionally, no standardized method to measure FO in radiographs following ssTHA has been introduced.…”

“…While the projected femoral offset (FO P ) can be directly measured in calibrated plain radiographs of the hip or pelvis, its projection can be significantly shortened due to hip rotation. [4,6,7] According to Lechler using standard femoral components, the effect of hip rotation on the projected femoral offset and rotation-corrected femoral offset has not been studied following ssTHA. [8,9] Due to the particular design of ssTHA, the long axis of the stem does not necessarily follow the long axis of the femoral shaft resulting in a wide range of acceptable varus or valgus positions.…”

Decisional conflict in surgical patients: Should surgeons care?

“…Controlling for this variable helps minimize the influence of implant specifications, such as neck length (femoral offset and leg length) and mode of biologic fixation (proximal versus distal), that may produce biomechanical changes and affect gait postoperatively. 24 The modified Helen Hayes marker set system has been validated for gait analysis, and we took great care to identify the hip joint centre before testing to account for inaccuracy that can occur with varying body habitus. Finally, each approach was performed by a single surgeon, which strengthens the internal validity of the study.…”