Squat and gait biomechanics 6 months following hip arthroscopy for femoroacetabular impingement syndrome

Abstract

The purpose of this study was to (i) assess whether squat and gait biomechanical measures improve in patients with femoroacetabular impingement syndrome (FAIS) 6 months after surgery compared to pre-operative measures and (ii) compare biomechanical properties to controls without FAIS. In this prospective study, biomechanical data during a double leg squat task and gait for 15 FAIS patients and 9 controls were collected using three-dimensional motion analysis. Data were collected in the FAIS group at two-time points, pre-operatively and 6-month post-operatively following arthroscopic hip surgery, and at a single time point for the healthy controls. Independent sample’s t-test were used to compare the FAIS group to the controls, and paired samples t-test were used to determine within-group differences before and after hip arthroscopy in the FAIS group. The results indicated that there were significant within-group increases for sagittal plane moment rate during the double leg squat task (P = 0.009) between the pre-operative and post-operative time points for the FAIS group. Between-group differences showed that FAIS patients pre-operatively exhibit slower squat velocities during the descent (P = 0.005) and ascent phase (P = 0.012) of a double leg squat when compared healthy controls. Reduced hip external rotation moments during gait (P = 0.02) were also found between FAIS patients pre-operatively and controls. In conclusion, alterations in hip biomechanics are present before surgery for FAIS when compared to healthy controls, and joint mechanics change 6 months after surgery. However, the biomechanical differences during a double leg squat and gait were minimal.

Hip Joint Kinematic Covariation During Gait Before and 1-Year After Hip Arthroscopic Surgery for Femoroacetabular Impingement Syndrome

“…The current study adds to previous studies on gait biomechanics before and after surgery for FAIS (7)(8)(9)(10)(11), as well as another study that investigated muscular synergy control of gait in patients with hip pathology (38). Rylander et al reported that patients demonstrated improvement of maximal hip internal rotation and sagittal plane range motion during gait following hip arthroscopic surgery for FAIS (7).…”

“…We acknowledge that the sample size of the study is small, however, the longitudinal design evaluating patients at 1-year after hip arthroscopy is valuable because extremely limited data exists in this area (7)(8)(9). Challenges associated with patient attrition, the time burden of marker based motion analysis testing, and limitation in number of high volume hip arthroscopy centers capable of motion analysis testing contributes to the generally small sample sizes and limited number of postoperative biomechanical studies in FAIS and (7)(8)(9)(10)(11). Other studies have attempted to overcome this by including patients undergoing any type of surgery for FAIS (open vs. arthroscopic), ( 9) and have reported on short term outcomes (10,11).…”

“…All previous studies examining gait kinematics in people with FAIS and before and after surgery have used a traditional analysis approach by statistically comparing discrete biomechanical variables (i.e., maximum or minimum values) in each plane of motion (7)(8)(9)(10)(11). A draw back to this analysis approach is that it eliminates the majority of biomechanical data collected during the task.…”

“…A recent systematic review found that across studies, the main hip joint kinematic differences between people with FAIS and healthy controls are lower peak hip extension angles, less total sagittal plane hip joint range of motion and less peak internal rotation during the stance phase of walking (6). Although these studies establish that movement patterns during walking are different between people with FAIS and healthy controls, evidence on hip biomechanics before and after arthroscopic surgery for FAIS remains limited (6)(7)(8)(9)(10)(11). Rylander and colleagues reported that following arthroscopic hip surgery for FAIS patients demonstrated improved sagittal plane and internal hip joint range of motion during walking (7,8).…”

“…Rylander and colleagues reported that following arthroscopic hip surgery for FAIS patients demonstrated improved sagittal plane and internal hip joint range of motion during walking (7,8). However, more recent studies examining gait kinematics before and after hip arthroscopic surgery have reported no differences in hip kinematics after this surgical procedure (10,11). Significantly reducing hip joint kinematic data using traditional analyses may be the potential reason for the inconsistency among these biomechanical studies before and after surgery for FAIS.…”