Center-edge Angle Research Articles

Combined assessment of acetabular coverage and femoral head-neck shapes predicts osteoarthritis progression after periacetabular osteotomy.

Postoperative osteoarthritis (OA) progression is a major determinant of failure after curved periacetabular osteotomy (CPO). A large postoperative combination angle, i.e., the combination of computed tomography-based anterior center edge and alpha angles, is associated with femoroacetabular impingement after CPO, but its association with postoperative OA progression is unclear. We aimed to identify the anatomical parameters that can lead to OA progression after CPO and the impact of the combination angle on the same. We included 90 hips that were subjected to CPO at our center between March 2013 and March 2018. Seventeen hips showed OA progression with an increase in the Tönnis classification after surgery; 73 hips showed no progression. Radiographic anatomical parameters, including the lateral and anterior center edge angles, femoral and acetabular anteversion, and combination angle, and clinical outcomes, including modified Harris Hip Scores (mHHSs), postoperative anterior impingement, and range of motion, were compared between the two groups. Statistical significance was set at P < 0.05. Postoperative OA progression was significantly affected by preoperative OA evidence (P = 0.017), acetabular anteversion < 5.0° (P = 0.003), and a combination angle > 107.0° (P = 0.025). Patients with radiographic OA progression were associated with poor mHHSs (P = 0.017) and high frequencies of anterior impingement with a limited hip flexion and internal rotation angle. OA progression after CPO may be associated with preoperative evidence of OA and postoperative acetabular retroversion as well as a large combination angle. Surgeons should focus on the potential effects of preoperative OA grades, postoperative reduction in acetabular anteversion, and postoperative combination angle.

Poster 181: Hip Arthroscopy with Concomitant Periacetabular Osteotomy Demonstrates Excellent Outcomes and Survivorship at Minimum 10-Year Follow-Up

Objectives: Multiple studies have shown that hip arthroscopy with concomitant periacetabular osteotomy (PAO) is a safe and effective treatment option for patients presenting with Symptomatic acetabular dysplasia and intra-articular pathology. While excellent short- and mid-term outcomes have been previously reported, there exists a paucity of literature investigating long-term outcomes of hip arthroscopy with concomitant PAO. The purpose of this study was to report minimum 10-year follow-up results and survivorship of hip arthroscopy with concomitant PAO to treat acetabular dysplasia and intraarticular pathologies such as femoroacetabular impingement (FAI) and labral tears. Methods: Data from October 2010 to December 2012 was prospectively collected and retrospectively reviewed to identify patients undergoing hip arthroscopy with concomitant PAO. Patients were included in the present analysis if they had preoperative and minimum 10-year patient reported outcomes (PROs) documented for the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), Hip Outcome Scored Sports-Specific Subscale (HOS-SSS), and pain on a visual analog scale (VAS), as well as the International Hip Outcome Tool (iHOT-12) and patient satisfaction score on a 0-10 scale. Results: Fifteen patients were eligible for analysis and 12 had complete minimum 10-year follow-up (80.0%) at mean 10.2 years postoperation. There were 10 females (83.3%) and 2 males (16.7%) included in the study with a mean age and BMI of 24.4 years and 24.5 kg/m2, respectively. The mean lateral center-edge angle (LCEA) of all included hips in the analysis increased from 13.8° to 29.8° postoperatively ( P&lt;0.05) and the anterior center-edge angle (ACEA) increased from 14° to 28.8° postoperatively ( P&lt;0.05). Additionally, the Tönnis angle of acetabular inclination decreased from 17.9° to 7.3° postoperatively ( P&lt;0.05) and the alpha angle decreased from 56.5° to 52.1° postoperatively ( P&lt;0.05). There was significant improvement in all PROs from baseline to minimum 10-year follow-up (mHHS; NAHS; HOS-SSS, P&lt; 0.05). All patients achieved high rates of MCID for mHHS, NAHS, and HOS-SSS, as well as high rates of PASS for mHHS and VAS. The 10-year survivorship for all patients included in the analysis was 83.3% with 2 patients (16.7%) progressing to total hip arthroplasty (THA) at mean 58.0 months postoperatively. Additionally, 2 patients (16.7%) underwent subsequent ipsilateral revision hip arthroscopy at mean 79.5 months postoperatively. Conclusions: Patients with dysplasia and intra-articular pathology such as labral tears and FAI can be safely treated using hip arthroscopy with concomitant PAO. These patients can achieve excellent long-term outcomes and high rates of survivorship at minimum 10 years postoperation.

Resolving residual acetabular dysplasia following successful brace treatment for developmental dysplasia of the hip in infants

AimsRadiological residual acetabular dysplasia (RAD) has been reported in up to 30% of children who had successful brace treatment of infant developmental dysplasia of the hip (DDH). Predicting those who will resolve and those who may need corrective surgery is important to optimize follow-up protocols. In this study we have aimed to identify the prevalence and predictors of RAD at two years and five years post-bracing.MethodsThis was a single-centre, prospective longitudinal cohort study of infants with DDH managed using a published, standardized Pavlik harness protocol between January 2012 and December 2016. RAD was measured at two years’ mean follow-up using acetabular index-lateral edge (AI-L) and acetabular index-sourcil (AI-S), and at five years using AI-L, AI-S, centre-edge angle (CEA), and acetabular depth ratio (ADR). Each hip was classified based on published normative values for normal, borderline (1 to 2 standard deviations (SDs)), or dysplastic (&gt; 2 SDs) based on sex, age, and laterality.ResultsOf 202 infants who completed the protocol, 181 (90%) had two and five years’ follow-up radiographs. At two years, in 304 initially pathological hips, the prevalence of RAD (dysplastic) was 10% and RAD (borderline) was 30%. At five years, RAD (dysplastic) decreased to 1% to 3% and RAD (borderline) decreased to &lt; 1% to 2%. On logistic regression, no variables were predictive of RAD at two years. Only AI-L at two years was predictive of RAD at five years (p &lt; 0.001). If both hips were normal at two years’ follow-up (n = 96), all remained normal at five years. In those with bilateral borderline hips at two years (n = 21), only two were borderline at five years, none were dysplastic. In those with either borderline-dysplastic or bilateral dysplasia at two years (n = 26), three (12%) were dysplastic at five years.ConclusionThe majority of patients with RAD at two years post-brace treatment, spontaneously resolved by five years. Therefore, children with normal radiographs at two years post-brace treatment can be discharged. Targeted follow-up for those with abnormal AI-L at two years will identify the few who may benefit from surgical correction at five years’ follow-up.Cite this article: Bone Joint J 2024;106-B(7):744–750.

Effect of lumbosacral transitional vertebra on developmental alterations of the hip: a quantitative investigation of the lumbo-pelvic-hip complex via whole-body computed tomography.

Lumbosacral transitional vertebra (LSTV) is a common spinal variant, with the reported prevalence varying from 8.1% to 36%. LSTV has been shown to alter the lumbo-pelvic parameters and reduce the benefits of total hip arthroplasty, but the specific effects of LSTV on hip development remain unclear. The aim of this study was thus to investigate the impact of LSTV on developmental alterations of the hip. A total of 310 individuals were categorized into three groups according to whole-body computed tomography (CT) imaging: a group with sacralization of 23 presacral vertebrae (PSV) (n=102), a group with lumbarization of 25 PSV (n=108), and a normal control group with 24 PSV (n=100). Quantitative parameters of the lumbo-pelvic-hip complex (LPHC) including lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), axial and sagittal acetabular anteversion angle (AAA), center-edge (CE) angle, Sharp angle, and femoral neck-shaft angle (FNSA) were measured and analyzed. Statistical analyses were used to compare the differences of these quantitative parameters among the three groups and to assess the relationship between hip and lumbar-pelvic parameters. Significant differences between each pair of three groups and the LSTV subgroups were only found in the sagittal AAA (left side: P=0.008; right side: P<0.001), with no differences found for the other parameters. Compared to the normal group (24 PSV), both the 23 PSV and 25 PSV groups exhibited increased values in the sagittal AAA, especially in the right side of the 23 PSV group. Only the sagittal AAA showed low-to-moderate positive correlations with pelvic parameters of PI (r=0.195-0.429; P=0.001-0.08) and PT (r=0.239-0.605; P=0.001-0.03). Variations of LSTV are correlated with the hip anatomical development via LPHC transmission and may potentially reduce the sagittal acetabular coverage, particularly in the 23 PSV subtype on the right side.

Poster 218: Localized Acetabular Bone Density Distributions Are Altered in Unilateral Femoral Acetabular Impingement

Objectives: Femoral acetabular impingement (FAI) can lead to bony and cartilage changes at the joint, and it has been suggested that changes in bone mineral density in the acetabulum may correlate with osteoarthritic degeneration of the hip. In this study, we aimed to use opportunistic quantitative computed tomography (QCT) to map density distributions across the acetabular region in patients with unilateral FAI and determine if there were differences between the affected and unaffected side. Furthermore, we assessed if these differences in density distributions were associated with radiographic measures of FAI. Methods: Twenty patients (age 31.9 (SD 9.2), 13 female) who underwent surgery for unilateral FAI and had an associated CT scan of both hips were included in this retrospective study. Both sides of the pelvis were segmented, and 3D models were created. Estimated bone density values were mapped across the bone models via QCT. A thin-spline semi-landmarking approach was used to allow density values at equivalent anatomical points to be compared within patients and across the group. With the contralateral side used as the control, differences in bone density between sides were calculated. A mixed effect linear regression model was used to determine if there were associations between the localized bone density and radiographic measures of Tonnis grade, alpha angle, lateral center edge angle (LCEA), and cross over sign, while controlling for age and sex. To visualize the data, density changes and statistical results were color-mapped to the bone models. Results: Overall, several regions of the acetabulum were found to have increased bone density in the affected side compared to the contralateral (Figure 1). Specifically, the anterior-superior parts of the acetabular rim appeared to be most affected, along with the posterosuperior region (Figure 2). Limited associations were found between localized density and the clinical variables, with the most notable finding being a region of the superior rim that was found to be associated with the alpha angle (Figure 3). Conclusions: FAI leads to distinct patterns of bone density changes around the acetabulum, although there is still variability at the level of the individual patient. It is unclear whether these changes in bone density may be related to the underlying condition, alterations in the patient’s mechanics due to pain, or a combination of these factors. Providing detailed density maps of the bony anatomy may also assist surgical providers in planning interventions. Further research may elucidate the relationship between bone density changes and long-term degeneration of the joint.

Poster 210: Flexible Athletes with Borderline Hip Dysplasia Achieve Successful and Similar Outcomes after Hip Arthroscopy Compared to Flexible Athletes without Borderline Hip Dysplasia

Objectives: To compare minimum 2-year patient-reported outcomes and achievement of clinically significant outcomes in flexibles athletes with and without borderline hip dysplasia (BHD) undergoing primary hip arthroscopy for femoroacetabular impingement syndrome (FAIS) with capsular plication. Methods: Data was prospectively collected for patients undergoing primary hip arthroscopy for FAIS with borderline hip dysplasia (BHD), defined as a lateral center edge angle (LCEA) of 18° to 25°, with primary participation in a sport with high flexibility requirement including dance, gymnastics, figure skating, yoga, cheerleading, and martial arts. These patients were matched 1:2 to flexible athletes with an LCEA &gt;25° controlling for age, sex, body mass index (BMI) and follow up duration. Preoperative and minimum 2-year postoperative patient-reported outcomes included: Hip Outcome Score (HOS) Activities of Daily Living, HOS Sports Scale, International Hip Outcome Score 12, modified Harris Hip Score, and Visual Analog Scale for Pain. Cohort-specific Minimal Clinically Important Difference (MCID) and Patient Acceptable Symptom State (PASS) were calculated and compared between groups. Results: Fifty-two flexible athletes with BHD were matched to 104 flexible athletes without BHD. Similar sport participation (45% dance vs. 41%, p=0.874) and level of competition (74% vs. 74% recreational, p=0.877) were observed. Preoperative LCEA (22.2° ± 1.6 vs. 31.5° ± 3.9, p &lt; 0.001) and Tönnis angle (10.9 °± 3.7 vs. 5.8° ± 4.4, p &lt; 0.001) differed significantly between groups. Capsular plication was performed in all cases (100% and 100%, p = 1.000). Both groups achieved significant improvement in all PROs (p ≤ 0.001) with no differences in PROs between groups (p ≥ 0.147). High MCID (95.7%, 94.8%) and PASS (71.7%, 72.2%) achievement for any PRO was observed with no differences between groups (p ≥ 0.222). Conclusions: Flexible athletes with BHD achieve successful and similar outcomes to those without BHD after primary hip arthroscopy for FAIS with capsular plication.

Poster 203: Staged Hip Arthroscopy and Periacetabular Osteotomy Versus Hip Arthroscopy Alone in Patients with Borderline Hip Dysplasia: A Propensity-Matched Study

Objectives: The management of borderline hip dysplasia (BHD) remains an area of interest in the field of hip preservation. The purpose of this study was to (1) evaluate mean 2-year outcomes for patients with BHD treated with staged hip arthroscopy and periacetabular osteotomy (PAO) to those who underwent hip arthroscopy alone, and (2) evaluate rates of complications, hardware removal, reoperations, conversions to total hip arthroplasty (THA), along with conversions to PAO. Methods: Hips with a lateral center-edge angle (LCEA) values 18° ≤ LCEA &lt; 25° that underwent a hip arthroscopy for femoroacetabular impingement syndrome (FAIS) between January 2018 and June 2022 were reviewed. Patients who underwent staged periacetabular osteotomy and hip arthroscopy were identified. Staged hips were propensity-matched 1:4 to other borderline dysplastic hips that underwent hip arthroscopy alone. Matching was performed based on age, sex, and body-mass index (BMI). Patient-reported outcomes (PROs) were collected, including Hip Outcome Score – Activities of Daily Living (HOS-ADL), HOS-Sports Specific (HOS-SS) subscale, 12-item International Hip Outcome Tool (iHOT-12) questionnaire, Patient-Reported Outcomes Measurement Information System-Pain Interference (PROMIS-PI) subscale, and PROMIS-Physical Function (PROMIS-PF) subscale. Cohort-specific minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) thresholds were calculated. Postoperative PROs, rates of MCID/PASS achievement, and rates of reoperation and conversion to THA were compared. Results: Twenty-four patients who underwent staged hip arthroscopy and PAO were successfully matched to 96 patients who underwent hip arthroscopy alone. Both groups were similar in terms of age, sex, and BMI. The patients who underwent a PAO had smaller LCEAs and larger Tönnis angles (21.0° vs. 23° and 11.6° vs. 9.1°, respectively). Both groups demonstrated significant improvement in PROs at minimum 1-year postoperatively (p &lt; 0.001, for all). There were no significant differences in postoperative PRO scores between the groups (p ≥ 0.223, for all). There were no significant differences in MCID/PASS achievement (p ≥ 0.224. for all). There were no reoperations or conversion to THA in the staged hip arthroscopy and PAO group. In the hip arthroscopy alone cohort, reoperation rates were 5.2% and conversion to THA occurred in 1% of the patients. There were no significant differences in secondary surgery rates between the groups (p = 1.000). Three patients in the hip arthroscopy alone group ultimately underwent PAO, 1 underwent a proximal femoral osteotomy (PFO), and one underwent a revision hip arthroscopy. These female patients were young and athletic with an LCEA &lt; 20°. Conclusions: Patients undergoing staged PAO and hip arthroplasty and isolated hip arthroplasty for treatment of BHD demonstrate similar clinical improvement. Rates of revision surgery and conversion to THA were similarly low. A small subset of patients who were initially treated arthroscopically ultimately received a PAO. This group was entirely made up of young, athletic female patients. This is encouraging early data and more long-term data is needed to evaluate the differences in survivorship. [Figure: see text]

Paper 16: Long-term Outcomes of Primary Hip Arthroscopy: Multicenter Analysis at Minimum 10-Year Follow-Up with Attention to Labral and Capsular Management

Objectives: Hip arthroscopy is rapidly advancing, with literature increasingly reporting positive outcomes at short- and mid-term follow-up; however, available long-term data remains limited. The purpose of this study is to evaluate long-term outcomes of primary hip arthroscopy at minimum 10-year follow-up at two academic centers by describing patient-reported outcomes (PROs) and determining reoperation, revision, and total hip arthroplasty (THA) rates. Methods: Primary hip arthroscopies performed between January 1988 and April 2013 at 2 academic centers were evaluated for postoperative PROs including Visual Analogue Scale (VAS), Tegner Activity Scale score, Hip Outcome Score Activities of Daily Living and Sport Scale (HOS-ADL/HOS-SS), modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), 12-item International Hip Outcome Tool (iHOT-12), surgery satisfaction, function, and reoperations. Results: Two-hundred ninety-four primary hip arthroscopies with a mean age of 40±14 years; 66% female; and a mean body mass index (BMI) of 27±6 kg/m2 were followed for mean 12±3 years (range: 10-24). Labral debridement and repair were performed in 41% and 59% of patients, respectively. All patients underwent interportal capsulotomy and 2% underwent T-capsulotomy. Eleven percent of patients underwent capsular repair. At final follow-up, patients reported mean VAS at rest of 2±2, with use of 3±3, iHOT-12 of 68±27, NAHS of 81±18, mHHS of 79±17, HOS-ADL of 82±19, and HOS-SS of 74±25. Mean surgical satisfaction was 8.4±2.4 (Table 1). Sixty-five hips (23%) underwent THA and 33 (11%) underwent revision arthroscopy (Table 2). Risk factors for THA included older age (p&lt;0.001), higher BMI (p&lt;0.001), lower lateral center-edge angle (p=0.039), larger alpha angle (p=0.001), higher Tönnis grade (p=0.011), labral debridement (p=0.004), and capsular nonrepair (p=0.030). Patients undergoing combined labral and capsular repair demonstrated a THA conversion rate of 3% compared to 31% for patients undergoing combined labral debridement and capsular nonrepair (p=0.006) (Table 3). Labral repair trended towards increased 10-year THA-free survival (84% vs. 77%, p=0.085) while capsular repair demonstrated significantly increased 10-year THA-free survival (97% vs 79%, p=0.032) (Figure 1). Conclusions: At minimum 10-year follow-up, patients undergoing primary hip arthroscopy demonstrated high rates of satisfaction and acceptable outcome scores. In total, 11% of patients underwent revision hip arthroscopic surgery with a THA conversion rate of 23%. Conversion to THA was associated with patient factors including older age and higher Tönnis grade as well as potentially modifiable surgical factors including labral debridement and capsular nonrepair.

Decrease in pelvic incidence after adult spinal deformity surgery is a predictive factor for progression of hip joint osteoarthritis

BackgroundThis study aimed to evaluate the association between spinopelvic alignment parameters and hip osteoarthritis progression after spinal alignment correction surgery for adult spinal deformity, focusing on the preoperative to postoperative change in spinopelvic alignment.MethodsThis retrospective study enrolled 100 adult spinal deformity patients (196 hip joints) who underwent spinal fusion surgery, after excluding four joints with previous total hip arthroplasty. Acetabular roof obliquity (ARO), center edge angle (CE) and Kellgren and Lawrence (KL) grade were measured in the hip joint. Spinopelvic alignment parameters were measured preoperatively and 1-month postoperatively and the changes (Δ) during this period were calculated. Patients were followed-up for ≥ 5 years and factors associated with KL grade progression at 5-years postoperatively were determined by logistic regression analysis.ResultsIn the analysis with all cases, KL grade progressed in 23 joints. Logistic regression analysis revealed age (OR: 1.098, 95% CI: 1.007–1.198, p = 0.019), ARO (OR: 1.176, 95% CI: 1.01–1.37, p = 0.026), and Δ PI (OR: 0.791, 95% CI: 0.688–0.997, p < 0.001) as parameters significantly associated with KL grade progression. On the other hand, in the analysis limited to 185 cases with 1-month postoperative KL grade of 0, KL grade progressed in 13 joints. Logistic regression analysis revealed PI-LL (OR: 1.058, 95% CI: 1.001–1.117, p = 0.04), ΔPI (OR: 0.785, 95% CI: 0.649–0.951, p < 0.001), and ΔCobb (OR: 1.127, 95% CI: 1.012–1.253, p = 0.009) as parameters significantly associated with progression.ConclusionsBoth the overall and limited analyzes of this study identified preoperative to postoperative change in PI as parameters affecting the hip osteoarthritis progression after spinal fusion surgery. Decrease in PI might represent preexisting sacroiliac joint laxity. Patients with this risk factor should be carefully followed for possible hip osteoarthritis progression.

Acetabular coverage exerts minimal influence on femoral head collapse and the necessity for surgical intervention in patients with osteonecrosis of femoral head

PurposeThe acetabular coverage in osteonecrosis of the femoral head (ONFH) affects the need for surgical intervention, and the collapse of the femoral head remains unclear. This study aimed to evaluate the relation between the acetabular coverage and the need for surgical treatment and femoral head collapse.MethodsThe study included 158 patients with 252 hips with glucocorticoid administration and idiopathic ONHF without osteoarthritis changes. The mean age at the first visit was 45.2 years, and the mean follow-up period was 92.2 months. All ONFH hips were subsequently divided into two groups: those needing surgical intervention and those without surgery. Additionally, it divided 167 initially non-collapsed hips into those that either later collapsed or not. Radiographic parameters with the centre-edge angle, acetabular roof obliquity, sharp angle, and necrotic location, following the guidelines of the Japanese Investigation Committee, were evaluated.ResultsThere were no significant differences in radiographic parameters between the 106 hips that underwent surgery and the 146 hips without surgery. Among the 167 hips without initial collapse, 91 eventually collapsed while 76 did not; their radiographic findings have no significant differences. The necrotic locations were significantly larger in hips requiring surgical intervention or femoral head collapse. Furthermore, 21.8% (55 out of 252 hips) had acetabular dysplasia, which did not significantly correlate with the necessity for surgical treatment or the incidence of femoral head collapse.ConclusionsAcetabular coverage has little effect on the necessity for surgical treatment and femoral head collapse in ONFH patients over a long-term follow-up.

An in-depth analysis of young adults with osteonecrosis secondary to developmental dysplasia of the hip who underwent total hip arthroplasty

BackgroundPatients with osteonecrosis of the femoral head secondary to DDH frequently require total hip arthroplasty (THA), but it is not well understood which factors necessitate this requirement. We determined the incidence of THA in patients who have osteonecrosis secondary to DDH and factors associated with need for THA.MethodsWe included patients who received closed or open reductions between 1995 and 2005 with subsequent development of osteonecrosis. We determined osteonecrosis according to Bucholz and Ogden; osteoarthritis severity (Kellgren-Lawrence), subluxation (Shenton’s line); neck-shaft angle; and acetabular dysplasia (centre-edge and Sharp angles). We also recorded the number of operations of the hip in childhood and reviewed case notes of patients who received THA to describe clinical findings prior to THA. We assessed the association between radiographic variables and the need for THA using univariate logistic regression.ResultsOf 140 patients (169 hips), 22 patients received 24 THA (14%) at a mean age of 21.3 ± 3.7 years. Associated with the need for THA were grade III osteonecrosis (OR 4.25; 95% CI 1.70-10.77; p = 0.0019), grade IV osteoarthritis (21.8; 7.55–68.11; p < 0.0001) and subluxation (8.22; 2.91–29.53; p = 0.0003). All patients who required THA reported at least 2 of: severe pain including at night, stiffness, and reduced mobility. Acetabular dysplasia and number of previous operations were not associated with the need for THA.ConclusionsWe identified a 14% incidence of THA by age 34 years in patients with osteonecrosis secondary to DDH. Grade III osteonecrosis (global involvement femoral head and neck) was strongly associated with THA, emphasising the importance to avoid osteonecrosis when treating DDH.

The Prevalence of Hip Dysplasia on Radiographs for Adolescent Idiopathic Scoliosis.

During radiographic assessment of adolescent idiopathic scoliosis (AIS), upright images frequently capture the hip. The purpose of this study was to assess the prevalence of radiographic hip dysplasia on postero-anterior (PA) scoliosis radiographs, as defined as a lateral center edge angle (LCEA) ≤25 degrees. All patients with upright PA scoliosis radiographs over a one-year study period at a single tertiary academic medical center (2020 to 2021) were included in the study. Radiographs containing the hip joints were annotated by 3 reviewers for left and right LCEA, and triradiate cartilage (TRC) status. Inter-rater reliability was determined among the 3 reviewers. Two hundred fifty patients {500 hips, 75.6% female, median age 14 [interquartile range (IQR)=3]} had PA scoliosis radiographs that captured the hip, which qualified for analysis. Seventy-four hips (14.8%) demonstrated evidence of dysplasia (LCEA ≤25 deg) in 55/250 patients (22%). The median LCEA was significantly lower in the dysplastic hip cohort (23.9 deg, IQR=4.8 deg), compared with those without dysplasia (33 deg IQR=7.3 deg; P =0.001). A higher percentage of dysplastic hip patients were female than male (72.7% vs. 27.3%). Patients with bilateral dysplasia had a similar LCEA ( 22.9 deg) [to those with unilateral dysplasia (22.9 deg left, 23.9 deg right, P =0.689)]. In a cohort of 250 AIS patients, 22% demonstrated evidence of hip dysplasia, as defined as an LCEA ≤2 degrees. The dysplastic patients were more likely to be female. Screening for hip symptomatology in AIS patients may be of benefit, considering the frequency of radiographic hip dysplasia in this population. III. Type of Evidence: diagnostic.

Long-term Survivorship and Outcomes of Patients Without Dysplasia Undergoing Capsular Repair During Primary Hip Arthroscopy for Femoroacetabular Impingement Syndrome

Background: There is a paucity of literature evaluating long-term outcomes and survivorship of patients undergoing primary hip arthroscopy with capsular repair for femoroacetabular impingement syndrome (FAIS). Purpose: To report 10-year survivorship and patient-reported outcomes (PROs) after primary hip arthroscopy with capsular repair for FAIS and evaluate the effect of capsular repair in patients at the highest risk for conversion to arthroplasty. Study Design: Cohort study; Level of evidence, 3. Methods: Data were prospectively collected and retrospectively reviewed on all patients undergoing primary hip arthroscopy with capsular repair between October 2008 and February 2011. Patients with a minimum 10-year follow-up on the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), and visual analog scale for pain (VAS) scores were selected. The preoperative and minimum 10-year follow-up Hip Outcome Score—Sports Specific Subscale (HOS-SSS) scores were also reported, if available. Patients with ipsilateral hip surgery, worker’s compensation, Tönnis osteoarthritis grade >1, and hip dysplasia (lateral center-edge angle <25°) were excluded. Survivorship, PROS, and clinical benefit—minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS)—were reported. An additional propensity-matched subanalysis was performed on patients at the highest risk for conversion to arthroplasty, comparing patients undergoing capsular repair to patients with unrepaired capsules. Results: A total of 145 (n = 130 patients) out of 180 eligible hips (n = 165 patients) had a minimum 10-year follow-up (80.6%). Also, 126 hips (86.9%) belonged to women, and 19 hips (13.1%) belonged to men. The mean patient age was 30.3 ± 12.9 years. The survivorship rate was 91% at the 10-year follow-up. The cohort experienced significant improvements (P < .001) in the mHHS, NAHS, HOS-SSS, and VAS for pain scores. Moreover, the cohort achieved high rates of the PASS for the mHHS (89.8%), high rates of the MCID for the mHHS (82.4%), and high rates of the MCID for VAS for pain (80.6%) scores. In the propensity-matched subanalysis performed on patients with the highest risk for arthroplasty, 29 hips with capsular repair were matched to 81 hips with unrepaired capsules. While both groups experienced significant improvements in all PROs (P < .05), the group without capsule repair trended toward a higher conversion to arthroplasty rate when compared with the repair group. In addition, an odds ratio was calculated for the likelihood of converting to arthroplasty after having an unrepaired capsule compared with capsular repair (2.54 [95% CI, 0.873-7.37]; P = .087). Conclusion: Patients undergoing primary hip arthroscopy with capsular repair experienced a high survivorship rate of 91% at a minimum 10-year follow-up. Patients who did not convert to arthroplasty saw favorable improvements in PROs and achieved high clinical benefit rates. In addition, among those patients at the highest risk for conversion to arthroplasty, a trend toward greater survivorship was observed with capsular repair.

Staged Hip Arthroscopy With Labral Repair, Femoroplasty, and Capsular Plication Followed by Periacetabular Osteotomy for Hip Dysplasia Results in Improved Outcomes and 100% Survivorship at Minimum 2-Year Follow-Up

PurposeTo assess patient-reported outcomes (PROs), clinically significant outcomes (CSOs), and survivorship following staged hip arthroscopy with labral repair, femoroplasty, and capsular plication followed by periacetabular osteotomy (PAO) for the management of femoroacetabular impingement syndrome (FAIS) and hip dysplasia (lateral center edge angle ≤25°). MethodsA prospectively maintained database was queried to retrospectively identify patients who underwent staged primary hip arthroscopy and PAO between 1/2018–10/2021 and had a minimum 2-year follow-up. PROs collected included, Hip Outcome Score Activities of Daily Living/Sports Subscale (HOS-ADL/SS), international Hip Outcome Tool-12 item questionnaire (iHOT-12), and Visual Analog Scale for Pain (VAS Pain). CSO achievement for minimal clinical important difference (MCID) and patient acceptable symptom state (PASS) were determined through cohort specific thresholds. Rates of reoperation, including, revision hip arthroscopy and conversion to total hip arthroplasty (THA) were evaluated to determine short-term survivorship. ResultsThirty-nine hips met criteria for inclusion, of which 35 hips had minimum 2-year follow up (89.7% compliance). Mean age was 25±9.1 years and 91.7% of patients were female. Respective pre- and postoperative radiographic outcomes were: Alpha angle 59.8±5.9 to 39.7±2.6°, Tönnis angle 14.6±5.6° to -1.0±2.9°, lateral center-edge angle 16.6±5.5° to 36.6±4.6°, and anterior center-edge angle 15.6±9.1° to 36.1±3.8°, with statistically significant differences pre- to postoperatively for all (P<0.001). Patients demonstrated significant improvement in all PROs pre- to postoperatively (P ≤0.004). MCID and PASS achievement rates for any PRO were 93.9% and 78.8%, respectively. There were no revision hip surgeries or conversion to THA at a mean 2.7±1.0-year follow-up. Four patients (11.1%) underwent hardware removal. One patient (2.8%) experienced a postoperative infection treated with incision and drainage. ConclusionsStaged hip arthroscopy and PAO for the management of hip dysplasia demonstrated improvement in PROs, high CSO achievement rates, and 100% survivorship at minimum 2-year follow-up.

Dysplastic Hips Have Decreased Iliofemoral Ligament Thickness on Coronal Sequences in Magnetic Resonance Imaging: A Matched Cohort Analysis

To characterize hip capsule thickness on advanced imaging in patients with and without hip dysplasia and to also evaluate differences in capsular thickness between patients with borderline and patients with true dysplasia. Patients evaluated by the senior author for concerns of hip pathology from June 2020 to June 2021 were queried and images reviewed to determine dysplasia status by lateral center-edge angle (LCEA) ≤25°. A group of patients without dysplasia was identified and matched for age, sex, and body mass index. Hip capsular thickness was quantified using magnetic resonance imaging. A subanalysis was conducted to compare patients with true dysplasia (LCEA < 20°) with patients with borderline dysplasia (LCEAs between 20° and 25°). The analysis included independent samples t tests, χ2 tests, and multivariable regression. A total of eighty patients were included, with a mean age of 31.8 ± 11.7 years, a mean body mass index of 26.6 ± 6.5 points, and 70% (56) female patients. Patients with dysplasia had a mean LCEA of 19.8 ± 4.3°. Patients with dysplasia had decreased capsular thickness compared with patients without dysplasia (2.75 ± 0.96 mm vs 3.52 ± 1.22 mm, P= .003). Multivariable regression showed decreased capsular thickness associated with decreased LCEAs (β= 2.804, R= 0.432, P < .001) and dysplasia (β= -0.709, R2= 0.056, P= .004). Results of a subanalysis of the dysplastic group examining differences between accepted definitions of borderline dysplasia and true dysplasia showed no significant differences in capsular thickness between the 2 groups (P= .379). Patients with hip dysplasia were found to have thinner iliofemoral ligaments in the coronal plane on magnetic resonance imaging on magnetic resonance imaging. Further investigation is needed to evaluate any potential implications with hip instability, given the thinner hip capsule demonstrated in this study. Level III, retrospective comparative prognostic trial.

Comparison of Salter innominate osteotomy and Pemberton pericapsular osteotomy combined with open reduction through medial adductor approach on acetabular development in the treatment of developmental hip dysplasia

Objective: Combined with open reduction through medial adductor approach, Salter innominate osteotomy (SIO) and Pemberton pericapsular osteotomy (PPO) methods are common procedures for the repair of incomplete acetabulum structure in patients with developmental hip dysplasia (DHD). The aim of this study is to compare the outcomes of acetabulum development in patients treated using these two methods. Patients and Methods: We retrospectively reviewed the medical records of 50 (65 hip joints) children who underwent SIO or PPO for DHD. Thirty-three patients underwent SIO and 32 patients underwent PPO as surgical treatment. The criteria of Tönnis, modified McKay, and Severin, and angles of acetabular index (AI) and acetabular center-edge (CE) angles of both groups were compared. Results: There were significant differences between two groups in the time of operation, follow-up time after operation, preoperative and postoperative AI angles, and postoperative 1styear CE angles. AI was detected as lower in the PPO group at 1stmonth postoperatively. Whereas, mean AI was detected as higher in the preoperative PPO group. In addition, the acetabular CE angle was significantly lower in the PPO group at 1styear postoperatively. However, there was no significant difference between the groups in terms of the CE angle value measured at the final follow-up. Conclusion: Salter innominate osteotomy and PPO methods used in the treatment of DHD have specific advantages and disadvantages. Preoperative and intraoperative evaluations of patients are very important in determining which procedure should be performed. When the choice is made properly, clinical and radiological results are both satisfactory.

Proximal femoral varus osteotomy for Legg–Calvé–Perthes disease: Do age and lateral pillar classifications influence short-to-mid-term clinical and radiological outcomes?

IntroductionProximal femoral varus osteotomy (FVO) is one of the most used treatment methods with acceptable outcomes for Legg–Calvé–Perthes disease (LCPD). We aimed to investigate the influence of age at disease onset and the Lateral Pillar classification on clinical and radiological outcomes of FVO surgery LCPD patients between 6–12years of age. HypothesisProximal FVO surgery in the early fragmentation phase of LCPD patients led to acceptable clinical and radiographic outcomes in a 3-year follow-up, regardless of preoperative age and Herring type. Material and methodsFifty patients with LCPD (Herring groups B, B/C, and C) who underwent FVO were retrospectively reviewed. We evaluated radiological [center-edge angle, extrusion index, epiphyseal index, acetabular index, articulo-trochanteric distance (ATD)] and clinical [hip abduction range of motion (ROM), Trendelenburg sign, pain, and Harris hip score (HHS)] outcomes with a follow-up of 37.3±10.5months (range: 24–180months). Finally, the overall treatment outcome was assessed using the Stulberg classification. ResultsThe ROC curve analysis did not reveal any significant relationship between age and clinical or radiological outcomes, and there was no predictable age cut-off for surgical outcomes (p=0.13). No significant difference was found in Stulberg classification at the follow-up between patients with type B, B/C, and C of the lateral pillar (p>0.05). DiscussionOur results demonstrated that open-wedge proximal FVO surgery in the early fragmentation phase of LCPD patients led to acceptable clinical and radiographic outcomes in a 3-year follow-up. Each sample of our study was very small and a lot of variables were measured, making this result not adequately strong enough to draw a robust conclusion. However, FVO surgery remains a possible suggestion for patients in the early fragmentation phase, and age and lateral pillar type may not be limiting factors. Level of evidenceIV; therapeutic retrospective cohort.

Less Acetabular Coverage Predicts the Failure of Core Decompression for Osteonecrosis of the Femoral Head: A Retrospective Cohort Study.

It is unclear whether less acetabular coverage is associated with the failure of core decompression (CD) for osteonecrosis of the femoral head (ONFH). This study aimed to investigate the clinical outcomes of CD for ONFH with small- or medium-sized pre-collapse lesions, and determine what factors, especially acetabular anatomical parameters, predict the failure of CD. Between January 2010 and December 2022, we retrospectively reviewed 269 consecutive CDs in 188 patients diagnosed with ONFH with small- or medium-sized pre-collapse lesions. The Kaplan-Meier method was used to evaluate the survival rate of CD for ONFH with progression of collapse or conversion to total hip arthroplasty (THA) as the endpoint. Univariate and multivariate logistic regression analyses were conducted to identify the potential risk factors for the failure of CD. Receiver operating characteristic (ROC) curve analysis was further performed with conversion to THA as the endpoint to determine the predictive value of these factors. The overall 5-year survival rate of CD for ONFH with small- or medium-sized pre-collapse lesions was 74.3% (95% confidence interval (CI) 69.0%-81.1%) with progression of collapse as the endpoint and 83.9% (95% CI 79.3%-88.7%) with conversion to THA as the endpoint. Univariate logistic regression analysis showed that bilateral affected hips was significantly associated with progression of collapse, and center-edge angle (CEA), sharp angle, acetabular head index (AHI), as well as acetabular depth ratio (ADR) were significantly associated with both progression of collapse and conversion to THA. Multivariate logistic regression analysis further indicated that CEA and AHI were independent risk factors for both progression of collapse and conversion to THA. ROC curve analysis with conversion to THA as the endpoint revealed that the cutoff values for CEA and AHI were 26.8° (sensitivity = 74.4%, specificity = 78.6%, area under the curve (AUC) = 0.809) and 79.8 (sensitivity = 78.4%, specificity = 73.8%, AUC = 0.818), respectively. CD showed satisfactory clinical outcomes for ONFH with small- or medium-sized pre-collapse lesions where less acetabular coverage with a CEA < 26.8° or AHI < 79.8 was identified as an independent risk factor for the failure of CD.

Outcome Scores and Survivorship of Patients Undergoing Primary Hip Arthroscopy With Borderline Hip Dysplasia: A Propensity-Matched Study With Minimum 10-Year Follow-up

Background: Patients with borderline hip dysplasia (BHD) and concomitant femoroacetabular impingement syndrome (FAIS) have demonstrated similar outcomes at short- and midterm follow-up compared with equivalent patients without dysplasia. However, comparisons between these groups at long-term follow-up have yet to be investigated. Purpose: To compare long-term clinical outcomes between patients with BHD undergoing primary hip arthroscopy for FAIS versus matched control patients without BHD. Study Design: Cohort study; Level of evidence, 2. Methods: A retrospective cohort study was conducted on patients with BHD (lateral center-edge angle, 18°-25°) who underwent hip arthroscopy for FAIS between January 2012 and February 2013. Patients were propensity matched in a 1:3 ratio by age, sex, and body mass index to control patients without BHD who underwent primary hip arthroscopy. Groups were compared in terms of patient-reported outcomes (PROs) preoperatively and at 10 years postoperatively, including the Hip Outcome Score Activities of Daily Living subscale (HOS-ADL) and Sports subscale (HOS-SS), modified Harris Hip Score, 12-item International Hip Outcome Tool, visual analog scale (VAS) for pain and satisfaction. Achievement rates for minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) were compared between groups. Kaplan-Meier survivorship curves were assessed between groups. Results: At a mean follow-up of 10.3 ± 0.3 years, 28 patients with BHD (20 women; age, 30.8 ± 10.8 years) were matched to 84 controls who underwent primary hip arthroscopy. Both groups significantly improved from preoperative assessment in all PRO measures at 10 years (P < .001 for all). PRO scores were similar between groups, aside from HOS-SS (BHD, 62.9 ± 31.9 vs controls, 80.1 ± 26.0; P = .030). Rates of MCID achievement were similar between groups for all PROs (HOS-ADL: BHD, 76.2% vs controls, 67.9%, P = .580; HOS-SS: BHD, 63.2% vs controls, 69.4%, P = .773; modified Harris Hip Score: BHD, 76.5% vs controls, 67.9%, P = .561; VAS pain: BHD, 75.0% vs controls, 91.7%, P = .110). Rates of PASS achievement were significantly lower in the BHD group for HOS-ADL (BHD, 39.1% vs controls, 77.4%; P = .002), HOS-SS (BHD, 45.5% vs controls, 84.7%; P = .001), and VAS pain (BHD, 50.0% vs controls, 78.5%; P = .015). No significant difference was found in the rate of subsequent reoperation on the index hip between groups. Kaplan-Meier survival analysis demonstrated comparable survivorship at long-term follow-up (P = .645). Conclusion: After primary hip arthroscopy, patients with BHD in the setting of FAIS had significantly improved PRO scores at 10-year follow-up, comparable with propensity-matched controls without BHD. Rates of MCID achievement were similar between groups, although patients with BHD had lower rates of PASS achievement. Patients with BHD had similar long-term hip arthroscopy survivorship compared with controls, with no significant difference in rates of revision hip arthroscopy or conversion to total hip arthroplasty.

Minimum 10-Year Survivorship of Uncemented Acetabular Reconstruction With Bulk Femoral Head Autografting in Crowe Type IV Developmental Hip Dysplasia

BackgroundIn total hip arthroplasty (THA) for severe dislocations such as Crowe type IV developmental dysplasia of the hip (DDH), sufficient bone volume for stable fixation of the acetabular component can be achieved by placing a reinforcing bone graft prepared from the resected femoral head into the deficient acetabulum. The purpose of the current study was to examine the long-term survivorship of uncemented THA in conjunction with a bulk femoral head autograft in patients who have Crowe type IV DDH. MethodsA total of 35 patients (42 hips) who have Crowe type IV DDH and underwent THA using uncemented cup fixation with bulk femoral head autografting were followed up for a mean period of 15.0 years (range, 10.0 to 20.0) postoperatively. Anteroposterior pelvic radiographs were used for measurements such as the horizontal coverage of the grafted bone and the center-edge angle. Kaplan–Meier survivorship analyses were performed with revision of the acetabular component as the endpoint. ResultsThe Kaplan–Meier analysis indicated 15-year survival rates of 90.4%. The mean horizontal coverage of grafted bone was 46.1% (range, 23.7 to 66.0), and there were 16 cases with horizontal coverage of ≥ 50%. There was no difference in the appearance of a thin (< 1 mm) radiolucency line around the cup between cases with < 50% versus ≥ 50% of the horizontal coverage of grafted bone (4 versus 2 hips; P = .446). Trabecular bridging and remodeling were seen in all cases after mean periods of 4.1 and 9.0 months postoperatively, respectively. Trabecular reorientation was seen in 41 of 42 hips (97.6%) at a mean follow-up of 19.9 months. ConclusionsAcetabular reconstruction with femoral bulk bone grafting for Crowe type IV DDH resulted in high survival rates and was a good method to restore bone stock and obtain long-term fixation.