Daniel Varin

Does the anterior approach for THA provide closer-to-normal lower-limb motion?

The purpose of this study was to compare the muscle-sparing anterior approach for total hip arthroplasty to a traditional lateral approach using 3D motion analysis. Kinematics and kinetics of walking were obtained for 40 patients (20 anterior and 20 lateral) and 20 control participants. Participants were assessed six to twelve months postoperatively. It was hypothesized that the anterior group would have closer-to-normal range of motion, moments, and powers than the lateral group. Both surgical groups had gait anomalies, such as significantly lower peak hip abduction moments. It is therefore thought that other variables such as preoperative gait adaptations, trauma from the surgery, or postoperative protection mechanisms for avoiding loading the prosthesis might be more influential factors than surgical approach when determining function after surgery.

Does the anterior approach for total hip arthroplasty better restore stair climbing gait mechanics

While total hip arthroplasty (THA) provides pain relief and restores mobility, gait anomalies persist even years after surgery. A muscle sparing surgical approach could result in better postoperative gait mechanics. Our purpose was to compare both the anterior muscle sparing approach and the direct lateral approach (LAT) to a matched control group by using three‐dimensional motion analysis while performing stair ascent and descent tasks. Lower‐limb kinematics and kinetics were recorded for 20 patients that had an anterior approach (ANT), 20 that had a LAT, and 20 age‐ and weight‐matched control participants. Patients were assessed on average 10 months after surgery. Compared to the control group, during stair ascent, the anterior group had reduced peak hip extension, peak hip flexion moment, and peak hip power. The lateral group had reduced peak hip abduction, hip frontal plane range of motion, and peak hip internal rotation. In stair descent, the anterior group had reduced peak hip flexion, peak hip abduction moment and internal rotation, as well as peak hip power. The lateral group had reduced peak hip flexion, peak knee extension moment, and peak hip power. Therefore, gait anomalies persist after THA for both approaches, which could be due to other factors such as preoperative gait adaptations.

Gait and Motion Analysis of the Lower Extremity After Total Hip Arthroplasty: What the Orthopedic Surgeon Should Know

This article presents critical issues related to the interpretation of biomechanical findings of the hip joint for patients having undergone hip arthroplasty. The use of a gait, or biomechanical, analysis provides objective evidence of the efficiency of the treatments or the effectiveness of hip replacement approaches. Based on our biomechanical analysis, patients who have undergone total hip arthroplasty use a stair ascent and descent strategy allowing them to significantly reduce loading at the prosthetic hip joint. Since hip joint reaction forces are highly dependent on muscle activation, the THA group have adopted a neuromuscular control strategy that is enabling them to reduce loading on the prosthetic hip joint. It could also be a joint loading pattern that stems from a muscular deficiency emerging either from several years of loading avoidance on the affected hip joint or from the surgical procedure. Therefore, a biomechanical analysis of human motion is a valuable tool for the orthopedic surgeon to objectively quantify joint motion and the forces producing this motion.

Lower-Limb Joint Mechanics after Total Hip Arthroplasty during Sitting and Standing Tasks

While the effect of total hip arthroplasty on the operated limb mechanics is well documented, little is known on its effect on the contralateral limb. The purpose of this study was to measure the joint mechanics of both lower limbs during the tasks of sit‐to‐stand and stand‐to‐sit. Twenty total hip arthroplasty patients and 20 control participants performed three trials of each task from which 3D lower‐limb joint kinematics and kinetics were obtained. Total hip arthroplasty patients exhibited lower operated‐hip joint flexion, extension moments, and power, occurring most frequently near seat‐on and seat‐off. Despite these reduced kinetic variables in the operated hip, the joints of the non‐operated limb generated similar joint kinetics as the matched control participants. These results indicated the patients who underwent total hip arthroplasty could adopt a strategy that allowed them to reduce moments and power generated at the operated lower‐limb joints without overcompensating with the non‐operated leg. Although such a strategy may be desirable given that higher loads can increase friction and accelerate wear of the prosthesis, reduced loading may be an indication of inadequate muscle strength that needs to be addressed.

Comparison of total hip arthroplasty surgical approaches by Principal Component Analysis

Gait adaptations are persistent after total hip arthroplasty and can depend on the type of surgery. This study focused on two surgical approaches: anterior and lateral. To analyze gait adaptations, biomechanical analyses usually employ an a priori selection of the parameters that leads to incomplete or redundant information. In contrast, Principal Component Analysis (PCA) provides an efficient transformation of the dataset by automatically identifying the major sources of variability. The purpose of this study was to investigate differences in level-walking among three groups of participants using PCA: patients undergoing an anterior surgical approach, patients undergoing a lateral surgical approach, and healthy controls. Biomechanical descriptions of the extracted principal components aided in the interpretation of the statistically significant results obtained from multivariate analysis of covariance (MANCOVA) tests. A point system was introduced to summarize the results and guide the interpretation. PCA captured reduced magnitude in sagittal and frontal moments in the anterior approach group, and reduced sagittal peaks angle in the lateral group, as previously found with traditional analyses. PCA also identified significant pattern delays in the anterior group, unnoticed in previous studies. In conclusion, neither surgical approach restored normal gait functionality because lower extremity kinetics and kinematics alterations persisted at 300-day follow-up after the surgery, regardless of the technique.