Quantitative gait analysis after total hip arthroplasty through a minimally invasive direct anterior approach: A case control study

Introduction: Total Hip Arthroplasty (THA) leads to excellent clinical and functional results. The Minimally Invasive Anterior Approach (MIAA) theoretically allows rapid recovery and a reduction in the need for rehabilitation, but alterations in muscle and static balance have previously been demonstrated. Kinetic, kinematic and muscular alterations have been shown to persist up to 1 year postoperatively but data beyond 1 year postoperatively is lacking. Thus, the objective of this study was to compare the data from Quantitative Gait Analysis (QGA) coupled with electromyography (EMG), of patients one year postoperatively with THA through MIAA, compared to an asymptomatic control group. Hypothesis: We hypothesized that QGA and EMG parameters would not normalize beyond one year postoperatively. Patients and Methods: Twenty-seven patients were recruited, including 15 subjects (64.6 +/- 6.6 years) operated on by MIAA, who at 15.9 +/- 3.1 months postoperatively, along with 12 asymptomatic control subjects (68.9 +/- 9.7 years), who underwent QGA and maximal isometric muscle strength tests, coupled with EMG on the gluteus medius and maximus, Tensor Fascia Lata (TFL) and Sartorius muscles. The spatiotemporal parameters of walking (step length, walking speed, cadence, single leg support time), kinetics (vertical ground reaction forces, hip moments in the 3 planes) and kinematics (coxofemoral and pelvic amplitudes) were analyzed. Results: The walking speed was lower on the non-operated side of the experimental subjects (0.96ms-1 compared to 1.13ms-1 for asymptomatic [p= 0.018]), as was the step length on the operated side (0.53 m compared to 0.60m for asymptomatic [p = 0.042]). Maximal isometric muscle strength was lower in subjects operated on for the gluteus maximus and medius (p=0.004), compared to asymptomatic subjects. Moments were lower in the subjects operated on in extension (0.72 Nm on the operated side, 0.75 Nm on the non-operated side compared to 1.06 Nm for asymptomatic [p = 0.007 and p= 0.024]) and lateral rotation (0.09 Nm on the operated side, 0.05 Nm on the non-operated side compared to 0.16 Nm for asymptomatic subjects [p=0.009 and p= 0.0005]). Hip adduction amplitudes were lower on the operated side compared to asymptomatic subjects (3.93 degrees versus 9.14 degrees for asymptomatic [p = 0.005]). Pelvic amplitudes in the frontal plane were lower amongst operated subjects (0.44 degrees against 1.97 degrees for asymptomatic [p=0.041]). Pelvic amplitudes in the sagittal plane were higher in the operated subjects (15.74 degrees on the operated side, 15.43 degrees on the non-operated side compared to 9.65 degrees for asymptomatic [p= 0.041 and p= 0.032]). Discussion: Our initial hypothesis was validated, since walking deficits persisted beyond one year post-operatively after THA through MIAA. A decrease in maximal isometric muscle strength of the gluteus medius and gluteus maximus was observed, as well as an alteration of kinetic and kinematic parameters in the sagittal and frontal planes. The results were in agreement with the literature and reflected the establishment of compensatory mechanisms to overcome alterations in joint strength and range more than one year postoperatively. These results would allow rehabilitation programs to be more specific and would justify a study on the other approaches for THA. (C) 2022 Elsevier Masson SAS. All rights reserved.