The effects of cam femoroacetabular impingement corrective surgery on lower-extremity gait biomechanics
Highlights
► We compare gait biomechanics of pre- and post-surgery cam FAI patients, and controls. ► Despite significant hip pain reduction, normal gait is not restored after surgery. ► Post-surgery patients display reduced hip frontal and sagittal plane range of motion. ► Post-surgery patients have reduced peak hip abduction and internal rotation moments. ► Modified gait patterns and muscle impairment may explain post-surgery discrepancies.
Introduction
Cam femoroacetabular impingement (FAI) is a well-documented source of hip pain in young active adults [1], [2]. Usually its symptoms arise during movements that solicit the hip's range of motion (ROM) limits such as squatting [3], [4], but have also been reported during activities requiring normal hip ROM as seen during walking [5], [6]. Since FAI mainly affects young active individuals, conservative treatment plans are usually not favored as they require radical lifestyle changes and restrictions in physical activity. Consequently, FAI is primarily corrected by means of surgery [7]. Surgical correction of FAI can be achieved using an open [8], [9], arthroscopic [7], [10] or combined technique [11], [12], all of which aim to restore a normal femoral head–neck offset.
Several studies have shown reduction or suppression of hip pain after FAI surgery [2], [12], [13] using the Harris Hip Score [14] and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) [15]. Other studies have reported improvements in postoperative hip passive ROM [12], [16]. Few studies have investigated the three-dimensional (3D) lower-extremity joint kinematics and kinetics of individuals with FAI. These investigations demonstrated that FAI patients had restricted hip [17] and pelvic [18] mobility during tasks requiring large lower-extremity joint ROM, and reduced hip and pelvic motion in the frontal plane during level gait [19] compared to control subjects. Recently, two studies have compared the preoperative and postoperative lower-extremity joint kinematics of FAI patients [20], [21]. Specifically, Rylander et al. [21] assessed FAI patients during level gait, within 1 month before arthroscopic surgery and again 1 year postoperatively. Increased postoperative hip sagittal plane ROM of the affected leg was observed, which resulted primarily from increased maximum hip flexion angles.
FAI surgery is increasingly popular; nevertheless, no known study has analyzed both the 3D lower-extremity joint kinematics and kinetics to evaluate its outcome. It is important to investigate the effects of FAI on hip function during gait as its symptoms can arise during this common repetitive movement [5], [6]. Likewise, it is important to assess the kinetics during gait as it can provide valuable information about muscle function and impairment, and could affect treatment decisions. Understanding the effects of FAI on hip function, preoperatively and postoperatively, is essential in confirming that surgery effectively restores more normal hip biomechanics.
The purpose of this study was to determine the effects of FAI surgery by means of an open or combined technique on the affected lower-extremity joint mechanics during level walking by comparing the 3D hip, knee, ankle and pelvic angular displacements, as well as the hip, knee and ankle moments and powers of preoperative and postoperative FAI groups, and a healthy control group. We hypothesized that there would be no significant differences between postoperative and control groups with regards to the kinematic and kinetic variables of interest, suggesting that surgery effectively restored normal hip biomechanics of FAI patients.
Section snippets
Participants
Seventeen participants with unilateral symptomatic cam FAI were previously compared to fourteen healthy control subjects matched for age, sex and body mass index [19]. In the current study, ten of the seventeen participants with cam FAI returned for postoperative testing. Seven FAI participants did not return for postoperative testing for the following reasons: four declined to participate, one suffered a spinal disc hernia, one had hip resurfacing and one underwent surgery for severe leg pain,
Results
Postoperatively, WOMAC scores of FAI patients improved significantly with respect to hip pain (p = 0.035), but not to hip stiffness or function (p > 0.05) (Table 1).
No significant differences were noted between groups with regards to spatiotemporal parameters (p > 0.05). Similarly, no significant differences were found between affected and unaffected legs of postoperative patients with respect to spatiotemporal parameters and peak 3D vertical ground reaction forces (affected: 884 ± 153.8 N vs.
Discussion
This study compared the gait kinematics and kinetics of healthy control participants and cam FAI patients before and after surgery using an open or combined technique. Postoperatively, WOMAC pain scores improved significantly by 13.4 points. Despite these subjective improvements and contrarily to our hypotheses, the gait biomechanics of FAI patients did not return to normal following surgery.
Kinematic results revealed that hip frontal plane ROM of FAI patients during gait remained unchanged
Conclusion
The present study demonstrated that the affected lower-extremity joint biomechanics of cam FAI patients during level walking do not return to normal following surgery, despite significant reductions in hip pain. Although cam FAI is considered to be caused mainly by an osseous deformity of the femoral head–neck junction, it seems to be associated with aberrant hip function (i.e. muscle activation patterns, ligament tension and bone-on-bone contact) that has not yet been well identified. The
Conflict of interest statement
The authors have no conflict of interest to disclose.
Acknowledgments
The authors would like to acknowledge the contribution of Anna Fazekas and Kyle Kemp, research coordinators at the adult reconstruction division of the orthopaedic surgery department at the Ottawa Hospital, and Daniel Varin, research coordinator at the Human Movement Biomechanics Laboratory of the University of Ottawa. This research was partially supported by the Canadian Institutes of Health Research (#200334).
References (30)
- et al.
Arthroscopy for the treatment of femoroacetabular impingement in the athlete
Clinical Sports Medicine
(2006) - et al.
Anterior femoroacetabular impingement
Joint, Bone, Spine
(2007) - et al.
Femoroacetabular impingement: etiology and surgical concept
Operative Techniques in Orthopaedics
(2005) - et al.
Arthroscopic treatment of femoroacetabular impingement
Arthroscopy: The Journal of Arthroscopic and Related Surgery
(2006) - et al.
Arthroscopic technique of femoroacetabular impingement
Operative Techniques in Orthopaedics
(2005) - et al.
Combined arthroscopic and modified open approach for cam femoroacetabular impingement: a preliminary experience
Arthroscopy: The Journal of Arthroscopic and Related Surgery
(2009) - et al.
Femoroacetabular impingement alters hip and pelvic biomechanics during gait. Walking biomechanics of FAI
Gait & Posture
(2009) A Fortran package for generalized, cross-validatory spline smoothing and differentiation
Advances in Engineering Software
(1986)- et al.
Recovery of walking speed and symmetrical movement of the pelvis and lower extremity joints after unilateral THA
Journal of Biomechanics
(2004) - et al.
Lower limb biomechanics during gait do not return to normal following total hip arthroplasty
Gait & Posture
(2010)
Preoperative gait adaptations persist one year after surgery in clinically well-functioning total hip replacement patients
Journal of Biomechanics
Three-dimensional gait analysis in women with a total hip arthroplasty
Clinical Biomechanics
Time course and extent of functional recovery during the first postoperative year after minimally invasive total hip arthroplasty with two different surgical approaches—a randomized controlled trial
Journal of Biomechanics
Femoroacetabular impingement. An overlooked cause of hip pain
American Journal of Physical Medicine & Rehabilitation
Quality of life following femoral head–neck osteochondroplasty for femoroacetabular impingement
The Journal of Bone & Joint Surgery
Cited by (71)
A Smartphone App Shows Patients Return to Preoperative Gait Metrics 6 Weeks After Hip Arthroscopy, and Gait Metrics Have Low to Moderate Correlations With a Hip-Specific Patient-Reported Outcome Measure
2023, Arthroscopy, Sports Medicine, and RehabilitationArthroscopic Femoral and Acetabular Osteoplasties Alter the In Vivo Hip Kinematics of Patients With Femoroacetabular Impingement
2022, Arthroscopy, Sports Medicine, and RehabilitationBiomechanics of Cam Femoroacetabular Impingement: A Systematic Review
2022, Arthroscopy - Journal of Arthroscopic and Related SurgeryCitation Excerpt :In total, 222 records were excluded based on title and abstract screening, leaving 37 articles for full-text assessment of eligibility based on the inclusion criteria. From those, 12 studies4,11,12,17-25 met such criteria. All 12 studies were cross-sectional laboratory studies investigating the biomechanics of FAI patients compared to a healthy control population, with 3 studies containing an additional postsurgical cohort.
Pre- and postoperative in silico biomechanics in individuals with cam morphology during stair tasks
2021, Clinical BiomechanicsThe sporting hip
2021, A Comprehensive Guide to Sports Physiology and Injury Management: An Interdisciplinary Approach