Pre-operative gait kinematics and kinetics do not change following surgery in adolescent patients with femoroacetabular impingement.

BACKGROUND: Femoroacetabular impingement (FAI) is a condition where the femoral head-neck junction collides with the acetabulum. Open or arthroscopic treatment of FAI aims to increase hip motion while reducing impingement during passive or dynamic movements. RESEARCH QUESTION: What are the biomechanical characteristics of the hip and pelvis in adolescents and young adults diagnosed with FAI syndrome 1) pre-operatively compared to controls and 2) pre- to post-operatively? METHODS: 43 patients with FAI and 43 controls were included in the study. All patients with FAI had cam deformities and underwent unilateral hip preservation surgery (either open or arthroscopic). Pre- and post-operative imaging, patient-reported outcomes, and gait analysis were performed. Joint angles and internal joint moments were evaluated with an emphasis on the pelvis and hip. A comparative analysis was conducted to evaluate the gait patterns before and after surgical treatment, as well as to compare pre-operative gait patterns to a control group. RESULTS: 43 patients with FAI (28 female, 16.5 ± 1.5 yrs) and 43 controls (28 female, 16.0 ± 1.5 yrs) were included. Pre-operative patients with FAI had decreased stride length and walking speed compared to controls, with no significant change following surgery. There were no differences in sagittal and coronal plane hip and pelvis kinematics comparing pre- to post-operative and pre-operative to controls. Pre-operatively, differences in internal hip rotation angle (pre: 3.3˚, post: 3.9˚, controls: 7.7˚) and hip extensor moment (pre: 0.121, post: 0.090, controls: 0.334 Nm/kg) were observed compared to controls with no significant changes observed following surgery. SIGNIFICANCE: Compensatory movement strategies in pelvic and hip motion are evident during gait in patients with FAI, particularly in the sagittal and transverse planes. These strategies remained consistent two years post-surgery. While surgery improved radiographic measures and patient-reported outcomes, gait did not elicit biomechanical changes following surgical treatment.

A Surgical Treatment Algorithm for Restoring Pelvic Balance and Health-related Quality of Life in High-grade Lumbosacral Spondylolisthesis: Prospective Multicenter Cohort of 61 Young Patients.

STUDY DESIGN: Retrospective multicenter cohort-study. OBJECTIVE: We propose an evidence-based surgical algorithm for achieving normal pelvic balance while optimizing health-related quality of life (HRQoL) in high-grade spondylolisthesis. SUMMARY OF BACKGROUND DATA: The principles of surgical treatment for young patients with high-grade L5-S1 spondylolisthesis remain unclear. There is a growing body of evidence supporting the central role of pelvic balance in the postural control and biomechanics of subjects with high-grade spondylolisthesis. METHODS: This retrospective study assessed a multicenter cohort of 61 patients with high-grade L5-S1 spondylolisthesis. Classification and regression tree analysis was used to identify objective criteria associated with pelvic balance and HRQoL after surgery. RESULTS: The most important predictor of a postoperative balanced pelvis was a postoperative L5 incidence ≤63.5 degrees. With postoperative L5 incidence ≤63.5 degrees,a residual slip percentage 9% and performing an L5-S1 posterior lumbar interbody fusion (PLIF)/transforaminal lumbar interbody fusion (TLIF) increased the likelihood of achieving a balanced pelvis postoperatively. When L5 incidence was 63.5 degrees,a balanced pelvis was most likely achieved with fusion limited to L5 proximally, residual slip percentage ≤40%, and residual lumbosacral angle 98 degrees. Predictors of postoperative HRQoL were the preoperative HRQoL score, L5 incidence and slip percentage. CONCLUSIONS: A surgical algorithm is proposed to achieve normal pelvic balance, while optimizing HRQoL. The first step during surgery is to assess L5 incidence and if L5 incidence is <65 degrees, the next step depends on the pelvic balance. With a preoperative balanced pelvis, it is important not to reduce completely the slip percentage by leaving a slip percentage ≥10%. When the preoperative pelvis is unbalanced, a TLIF/PLIF at L5-S1 is recommended to facilitate correcting the angular deformity at L5-S1. If L5 incidence is ≥65 degrees,a TLIF/PLIF at L5-S1 should be performed to correct the angular deformity at L5-S1, and fusion should ideally end at L5 proximally, in addition to performing gradual reduction of the slip percentage. If fusion up to L4 is required, a lumbosacral angle ≥100 degrees is key.

Criteria for surgical reduction in high-grade lumbosacral spondylolisthesis based on quality of life measures.

PURPOSE: Although surgical reduction in high-grade lumbosacral spondylolisthesis is often performed in young patients, criteria for defining adequate reduction leading to optimal outcomes have yet to be defined. The purpose of this study is to determine if surgical reduction in pelvic balance, slip grade, lumbosacral angle and L5 incidence are associated with quality of life after surgery, based on specific criteria proposed previously in the literature. METHODS: A prospective cohort of 61 patients (14.4 ± 2.7 years) with high-grade lumbosacral spondylolisthesis was followed for a minimum of 2 years after surgery. SRS-22 scores, slip grade, lumbosacral angle, pelvic balance and L5 incidence were assessed before surgery and at the latest follow-up. Multivariable regression analyses were performed using postoperative SRS domain and total scores as the dependent variables. Independent variables consisted of the preoperative SRS scores, and specific criteria of pelvic balance, slip grade, lumbosacral angle and L5 incidence. The influence of slip grade, lumbosacral angle and L5 incidence on pelvic balance was also assessed. RESULTS: Obtaining a balanced pelvis postoperatively was mainly predictive of improved satisfaction with surgery and self-image and also tended to be associated with higher scores for other domains. Improved mental health was associated with reduction to a low-grade slip. Reduction in lumbosacral angle was not predictive of quality of life. Postoperative pelvic balance was mainly associated with preoperative pelvic balance, but there was a tendency for achieving normal pelvic balance when the postoperative L5 incidence was 60° or smaller. CONCLUSIONS: When performing surgery in young patients with high-grade lumbosacral spondylolisthesis, achieving normal pelvic balance is the key because it is associated with improved quality of life. Reduction to a low-grade slip is predictive of improved mental health, but reduction in lumbosacral angle is not associated with postoperative quality of life. There was a tendency for obtaining normal postoperative balance in patients with postoperative L5 incidence 60° or smaller. These slides can be retrieved under Electronic Supplementary Material.

Radiographic Assessment of Shoulder Position in 619 Idiopathic Scoliosis Patients: Can T1 Tilt Be Used as an Intraoperative Proxy to Determine Postoperative Shoulder Balance?

BACKGROUND: The purpose of this study is to assess radiographic shoulder measures from the preoperative to the postoperative time period, specifically to determine whether T1 tilt could be used as an intraoperative proxy for shoulder balance determination. This study focused on radiographic shoulder measures of 619 adolescent idiopathic scoliosis patients who underwent spinal deformity surgery. METHODS: A prospective, multicenter database of adolescent idiopathic scoliosis was queried to identify all patients who had undergone spinal deformity surgery with >2 years of follow-up postoperatively. Radiographic analysis focused on measures of shoulder balance: T1 tilt, clavicle angle, and radiographic shoulder height. RESULTS: A total of 619 patients were included in this analysis. Mean age at surgery was 14.8 years with 83% female. Mean preoperative curve size was 58.0 degrees. Mean T1 tilt preoperatively was -0.10 degrees and postoperatively 2.42 degrees. Mean clavicle angle preoperatively was -1.39 degrees and postoperatively 0.79 degrees. Mean radiographic shoulder height preoperatively was -7.04 mm and postoperatively 1.63 mm. All 3 radiographic parameters demonstrated reasonable correlation preoperatively and postoperatively to each other. To assess the viability of T1 tilt as an intraoperative proxy for shoulder balance, standardized ratios between the variables were created. Analysis of these ratios demonstrated little or no relationship preoperatively to postoperatively, hence the relationship of T1 tilt to radiographic shoulder height does not remain constant. CONCLUSIONS: Analysis of the relationship of T1 tilt to radiographic shoulder height from preoperative to postoperative did not demonstrate consistency. Lenke 3 and 6 curve patterns demonstrated preoperative to postoperative correlation, both with nonstructural proximal thoracic curves; however, for the remaining curve patterns T1 tilt cannot be used as an intraoperative proxy for shoulder balance. LEVEL OF EVIDENCE: Level IV.