Hip displacements and correctable scoliosis were prevalent in children with cerebral palsy registered in a Danish follow-up programme from 2010 to 2020.

AIM: We need a better understanding of non-surgical interventions for hip dislocations and scoliosis. This study estimated the cumulative incidence of problems among children with cerebral palsy and described the type and frequency of therapist-led interventions. METHODS: The study comprised 1482 children (58% male) aged 0-15 years, with a mean age of 3.6 years, who were registered in the Danish Cerebral Palsy Follow-up Programme from 2010 to 2020. We used the Kaplan-Meier estimator to examine the cumulative incidence of hip displacement, hip dislocation, correctable scoliosis and non-correctable scoliosis. The type and frequency of therapist-led interventions are reported descriptively. RESULTS: The cumulative incidence of hip displacement and hip dislocation were 15.8% and 3.5%, respectively, and 39.0% and 13.9% for correctable and non-correctable scoliosis. The most frequently reported type of therapist-led intervention was a joint range of motion exercise. We found that 60.5% with hip displacements and 43.8% with correctable scoliosis used a standing aid. A further 5.4% used a spinal orthosis to prevent deformity and 8.1% for stabilisation. CONCLUSION: Hip displacement and correctable scoliosis were prevalent in children with cerebral palsy, whereas the occurrence of hip dislocations and non-correctable scoliosis was low. The use of assistive aids was low.

Greater pelvic obliquity in adolescent idiopathic scoliosis combined with hip dysplasia.

BACKGROUND: Adolescent idiopathic scoliosis (AIS) is a spinal deformity that affects adolescents and poses a challenging public health problem. Compared to the general population, adolescents with AIS have a higher prevalence of hip dysplasia. However, the mechanisms underlying the impact of hip dysplasia on the coronal balance of the spine remain poorly understood. We hypothesized that the combination of AIS with hip dysplasia would exacerbate coronal imbalance. METHODS: We retrospectively analyzed the medical records and radiographs of adolescents diagnosed with AIS between 2015 and 2020. Participants were divided into two groups: those with hip dysplasia and those without. We recorded parameters related to the coronal deformity of the spine, sacral and pelvic obliquity, and center edge angle (CEA). We investigated differences in these parameters in those with and without hip dysplasia and analyzed their relationships in those with combined AIS and hip dysplasia. RESULTS: A total of 103 adolescents were included, 36 with hip dysplasia and 67 without. Those with hip dysplasia had significantly higher sacroiliac discrepancy (SID) compared to those without (t = - 2.438, P = 0.017). In adolescents with hip dysplasia, only iliac obliquity angle (IOA) was significantly correlated with SID (r = - 0.803, P < 0.001), with a linear relationship between them (r2 = 0.645, P < 0.001). CONCLUSIONS: The incidence of hip dysplasia is higher in the AIS population. In adolescents with combined AIS and hip dysplasia, pelvic obliquity is greater, potentially contributing to the increased prevalence of low back pain.

Insufficient stem antetorsion and lower cup abduction is a combined risk factor for posterior hip dislocation in patients undergoing THA for femoral neck fractures: a retrospective analysis.

BACKGROUND: The role of acetabular and femoral component positions with respect to the risk of post-operative instability and dislocation remains debated. In this study, we aimed to identify potential risk factors for early dislocation following primary total hip arthroplasty (THA) for displaced intracapsular femoral neck fractures (FNF) using radiological measurements. METHODS: We retrospectively analyzed data for patients who underwent cementless primary THA for FNF using a posterolateral approach between January 2018 and December 2021. Follow-up duration, age, sex, affected side, and mean time from THA to dislocation were recorded. Leg-length inequality, abductor lever arm, vertical and horizontal femoral offsets, vertical and horizontal hip centers of rotation, abduction, anteversion of the acetabulum and femoral prosthesis, and combined anteversion were measured. RESULTS: The study sample included 17 men and 34 women, with 21 and 30 patients undergoing left- and right-hip operations, respectively. The mean patient age was 70.18 ± 7.64 years, and the mean follow-up duration was 27.73 ± 13.52 months. The mean time between THA and dislocation was 1.58 ± 0.79 months. Seven patients (13.73%) sustained posterior dislocation of the hip. The abduction angle (36.05 ± 6.82° vs. 45.68 ± 8.78°) (p = 0.008) and anteversion of the femoral prosthesis (8.26 ± 4.47° vs. 19.47 ± 9.01°) (p = 0.002) were significantly lower in the dislocation group than in the control group. There were no significant differences in other parameters. CONCLUSIONS: Insufficient stem antetorsion combined with lower abduction angle of the acetabular component were associated with a high risk of dislocation, especially in patients with deep flexion or internal rotation of the flexed hip joint and knees, or in patients with a stiff spine or anterior pelvic tilt, impingement may then occur in the neck of the prosthesis and cup component, ultimately resulting in posterior dislocation. These findings could remind surgeons to avoid simultaneous occurrence of both in THA surgery. These results provide new insight into risk factors for hip dislocation in patients undergoing primary THA for FNF and may aid in reducing the risk of instability and dislocation. LEVEL OF EVIDENCE: Prospective comparative study Level II.

Previous lumbar spine fusion increases the risk of dislocation following total hip arthroplasty in patients with hip-spine syndrome: a systematic review and meta-analysis.

BACKGROUND: With life expectancy on the rise, there has been an increase in patients with concomitant degenerative hip and spine pathology, defined as hip-spine syndrome (HSS). Patients affected by HSS may require both total hip arthroplasty (THA) and lumbar spinal fusion (LSF), although there is a paucity of data regarding how the sequential timing of these procedures may influence clinical outcomes. This study aims to compare complications and spinopelvic parameters in patients with HSS who underwent either LSF first or THA first. METHODS: A systematic search of PubMed and Scopus was conducted for randomized and nonrandomized studies investigating complications and spinopelvic parameters in patients with HSS who had undergone THA and LSF. The Methodological Index for Non-Randomized Studies (MINORS) tool was utilized to assess the risk of bias in included studies. Relevant outcomes were pooled for meta-analysis. RESULTS: Eleven articles were included in this study. There was a significantly higher THA dislocation rate in patients who had undergone LSF first compared to those who had THA first (OR: 3.17, 95% CI 1.23-8.15, P = 0.02). No significant difference was found in terms of THA aseptic loosening (OR: 0.86; 95% CI 0.32-2.32, p = 0.77) and revision rate (OR: 1.18, 95% CI: 0.53-2.62) between these two groups. Individuals who received THA only showed a significantly lower risk of hip dislocation (OR: 0.14, 95% CI: 0.08-0.25, P < 0.00001) and THA revision (OR: 0.22, 95% CI: 0.14-0.36, P < 0.00001) compared to patients with a previous LSF. CONCLUSIONS: In HSS patients who underwent both LSF and THA, those who received LSF first displayed an increased risk of hip dislocation after subsequent THA. Additionally, the relative risks of dislocation and revision rate appeared significantly lower in patients who had undergone THA only when compared to THA patients with a history of previous LSF. Due to the impact of LSF on spinopelvic biomechanics, caution must be exercised when performing THA in individuals with instrumented spines. PROSPERO ID: CRD42023412447. LEVEL OF EVIDENCE: LL.

Clinical Outcomes and Associated Pathologies Following Pediatric Traumatic Hip Dislocations: A Systematic Review of the Literature.

INTRODUCTION: Pediatric traumatic hip dislocations are a rare condition that can have devastating short and/or long-term outcomes and associated pathologies (APs), including associated injuries (AIs) and long-term adverse events (LTAEs), with negative long-term sequelae. Currently, there are little data that exist on the rate of APs, with the most notable being avascular necrosis (AVN), for pediatric traumatic hip dislocations. The purpose of this systematic review is to evaluate the outcome relative frequency of dislocation direction, reduction type, and rate of APs for traumatic hip dislocations in the pediatric population. METHODS: A systematic review on the topic of traumatic hip dislocations in the pediatric population was performed using PubMed, ScienceDirect, Web of Science, CINAHL, and MEDLINE databases from database inception to March 30, 2023. Inclusion criteria was full-text English articles, addressed traumatic hip dislocations, and pediatric patients (<18 y old). RESULTS: A total of 24 articles (n=575 patients) met final inclusion criteria from a total of 219 articles retrieved from the initial search. For the average age of the included patients with reported age (n=433 patients), the frequency weighted mean was 9.50 years±1.75 years with a frequency weighted mean follow-up time of 74.05 months ±45.97 months (n=399 patients). The most common dislocation direction was posterior (86.4%), the most common treatment type was closed reduction (84.5%), AVN was the most common type of LTAEs (15.5% of APs), and labral/capsular injuries and acetabular fractures were the most common type of AIs (14.0% and 9.4% of APs, respectively). There were a combined total of 414 APs (72%) out of 575 total patients. CONCLUSION: Pediatric traumatic hip dislocations are associated with a high rate of AIs and LTAEs (72%, 414 APs out of 575 patients). AVN, labral/capsular injuries, and acetabular fractures are the most common APs after pediatric traumatic hip dislocations. Pediatric hip dislocations are usually posterior and commonly managed through closed reduction. LEVEL OF EVIDENCE: III, Systematic Review.

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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)]. CONCLUSIONS: 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. LEVEL OF EVIDENCE: III. Type of Evidence: diagnostic.

Dislocation Following Anterior and Posterior Total Hip Arthroplasty in the Setting of Spinal Deformity and Stiffness: Evolving Trends Using a High-Risk Protocol at a Single Tertiary Center.

BACKGROUND: Patients who have spinal stiffness and deformity are at the highest risk for dislocation after total hip arthroplasty (THA). Previous reports of this cohort are limited to antero-lateral and postero-lateral (PL) approaches. We investigated the dislocation rate after direct anterior (DA) and PL approach THA with a contemporary high-risk protocol to optimize stability. METHODS: We investigated patients undergoing THA who had preoperative biplanar imaging from January-December 2019. Patients were identified using radiographic criteria of spinal-stiffness (<10-degree change in sacral slope from standing to seated) and deformity (flatback deformity with >10-degree difference in pelvic incidence and lumbar lordosis). There were 367 patients identified (181 DA, 186 PL). The primary outcome was dislocation rate at 2-years postoperatively. Risk-factors for dislocation were evaluated using logistic regressions (significance level of 0.05). RESULTS: There were 6 (1.6%) dislocations in the entire cohort, with low dislocation rates for both DA (0.6%) and PL-THA (2.7%). We observed increased utilization of dual mobility with larger outer head bearings (>38 mm) with PL-THA (34.4 versus 5.0%, P < .01) and conversely increased utilization of 32-mm femoral-heads with DA-THA (39.4 versus 7.0%, P < .001). Surgical approach (PL) was not a significant risk-factor for dislocation (odds ratio: 5.03, P = .15). Patients who had a history of lumbar-fusion had 8-times higher odds for dislocation (OR: 8.20, P = .020). CONCLUSIONS: To the best of our knowledge, this is the largest series to date evaluating DA and PL-THA in the hip-spine 2B-group. Our results demonstrate lower dislocation rate than expected with either surgical approach using a high-risk protocol.

Surgical Approach Does Not Influence Instability Risk in Revision Total Hip Arthroplasty.

BACKGROUND: Although the direct anterior (DA) approach has increased in popularity for primary total hip arthroplasty (THA), there is limited evidence regarding its use for revision THA. It is unknown whether the dislocation benefit seen in the primary setting translates to revision cases. METHODS: This retrospective review compared the dislocation rates of revision THA performed through DA versus postero-lateral (PL) approaches at a single institution (2011 to 2021). Exclusion criteria included revision for instability, ≥ 2 prior revisions, approaches other than DA or PL, and placement of dual-mobility or constrained liners. There were 182 hips in 173 patients that met the inclusion criteria. The average follow-up was 6.5 years (range, 2 to 8 years). RESULTS: There was a trend toward more both-component revisions being performed through the PL approach. There were no differences in dislocation rates between the DA revision and PL revision cohorts, which were 8.1% (5 of 72) and 7.5% (9 of 120), respectively (P = .999). Dislocation trended lower when the revision approach was discordant from the primary approach compared to cases where primary and revision had a concordant approach (4.9 versus 8.5%), but this was not statistically significant (P = .740). No significant differences were found in return to operating room, 90-day emergency department visits, or 90-day readmissions. However, the length of stay was significantly shorter in patients who had DA revisions after a primary PL procedure (P = .021). CONCLUSIONS: Dislocation rates following revision THA did not differ between the DA and PL approaches irrespective of the primary approach. Surgeons should choose their revision approach based on their experience and the specific needs of the patient.

Early Prosthetic Hip Dislocation: Does the Timing of the Dislocation Matter?

BACKGROUND: Early dislocation following total hip arthroplasty (THA) is a common reason for revision. The purpose of this study was to determine if the acuity of the dislocation episode affects the risk of revision surgery. METHODS: A retrospective review of a national, all-payer administrative database comprised of claims from 2010 to 2020 was used to identify patients who had a prosthetic hip dislocation at various postoperative time intervals (0 to 7, 7 to 30, 30 to 60, and 60 to 90 days). Of the 45,352 primary unilateral THA patients who had sufficient follow-up, there were 2,878 dislocations within 90 days. Dislocators were matched 1:1 based on age, sex, and a comorbidity index with a control group (no dislocation). Demographics, surgical indications, comorbidities, ten-year revision rates, and complications were compared among cohorts. Multivariable logistic regression analysis was performed to identify risk factors for revision THA following early dislocation. RESULTS: Among matched cohorts, dislocation at any time interval was associated with significantly increased odds of subsequent 10-years revision (OR [odds ratio] = 25.60 to 33.4, P < .001). Acute dislocators within 7 days did not have an increased risk of all cause revisions at 10 years relative to other early dislocators. Revision for indication of instability decreased with time to first dislocation (<7 days: 85.7% versus 60 to 90 days: 53.9%). Primary diagnoses of posttraumatic arthritis (OR = 2.53 [1.84 to 3.49], P < .001), hip fracture (OR = 3.8 [2.53 to 5.72], P < .001), and osteonecrosis (OR = 1.75 [1.12 to 2.73], P = .010) were most commonly associated with revision surgery after an early dislocation. CONCLUSIONS: Dislocation within 90 days of THA is associated with increased odds of subsequent revision. Early dislocation within 7 days of surgery has similar all cause revision-free survivorship, but an increased risk of a subsequent revision for instability when compared to patients who dislocated within 7 to 90 days.

Does Surgical Approach Affect Dislocation Rate After Total Hip Arthroplasty in Patients Who Have Prior Lumbar Spinal Fusion? A Retrospective Analysis of 16,223 Cases.

BACKGROUND: Lumbar spinal fusion (LSF) is a risk factor for dislocation following total hip arthroplasty (THA). The effect of the surgical approach on this association has not been investigated. This study examined the association between the surgical approach and dislocation following THA in patients who had prior LSF. METHODS: We retrospectively reviewed 16,223 primary elective THAs at our institution from June 2011 to September 2022. Patients who had LSF prior to THA were identified using International Classification of Diseases (ICD) codes. Patients were stratified by LSF history, surgical approach, and intraoperative robot or navigation use to compare dislocation rates. There were 8,962 (55.2%) posterior, 5,971 (36.8%) anterior, and 1,290 (8.0%) laterally based THAs. Prior LSF was identified in 323 patients (2.0%). Binary logistic regressions were used to assess the association of patient factors with dislocation risk. RESULTS: There were 177 dislocations identified in total (1.1%). In nonadjusted analyses, the dislocation rate was significantly higher following the posterior approach among all patients (P = .003). Prior LSF was associated with a significantly higher dislocation rate in all patients (P < .001) and within the posterior (P < .001), but not the anterior approach (P = .514) subgroups. Multivariate regressions demonstrated anterior (OR [odds ratio] = 0.64, 95% CI [confidence interval] 0.45 to 0.91, P = .013), and laterally based (OR = 0.42, 95% CI 0.18 to 0.96, P = .039) approaches were associated with decreased dislocation risk, whereas prior LSF (OR = 4.28, 95% CI 2.38 to 7.69, P < .001) was associated with increased dislocation risk. Intraoperative technology utilization was not significantly associated with dislocation in the multivariate regressions (OR = 0.72, 95% CI 0.49 to 1.06, P = .095). CONCLUSIONS: The current study confirmed that LSF is a significant risk factor for dislocation following THA; however, anterior and laterally based approaches may mitigate dislocation risk in this population. In multivariate analyses, including surgical approach, LSF, and several perioperative variables, intraoperative technology utilization was not found to be significantly associated with dislocation risk.

Does Size Really Matter? Incidence of Periprosthetic Fractures After Femoral Osteotomy in Patients With Cerebral Palsy.

OBJECTIVE: Of children, 30% to 35% with cerebral palsy (CP) develop hip subluxation or dislocation and often require reconstructive hip surgery, including varus derotation osteotomy (VDRO). A recent literature review identified postoperative fractures as the most common complication (9.4%) of VDROs. This study aimed to assess risk factors for periprosthetic fracture after VDRO in children with CP. METHODS: A total of 347 patients (644 hips, 526 bilateral hips) with CP and hip subluxation or dislocation (129 females; mean age at index VDRO: 8.6 y, SD 3.4, range: 1.5 to 17.7; 2 Gross Motor Function Classification System (GMFCS) I, 35 GMFCS II, 39 GMFCS III, 119 GMFCS IV, 133 GMFCS V, 21 unavailable) were included in this retrospective, single-group intervention (VDRO) study at a tertiary referral center. Imaging and clinical documentation for patients age 18 years or younger at index surgery, treated with VDRO were reviewed to determine demographic data, GMFCS level, surgeon, type of hardware implanted, use of anticonvulsants and steroids, type of postoperative immobilization, presence of periprosthetic fractures, fracture location and mechanism, and time from surgery to fracture. Potential determinants of periprosthetic fractures were assessed using mixed effects logistic regression. RESULTS: Of 644 hips, 14 (2.2%, 95% CI: 1.3%, 3.6%) sustained a periprosthetic fracture, at a median of 2.1 years postoperatively (interquartile range: 4.6 y, range: 1.2 mo to 7.8 y). Patients with a fracture had a median age at index surgery of 7.3 years (interquartile range: 4.3, range: 2.8 to 17.8; 1 GMFCS II, 6 GMFCS IV, 7 GMFCS V). Periprosthetic fractures were not significantly related to age at index surgery ( P = 0.18), sex ( P = 0.30), body mass index percentile ( P = 0.87), surgery side ( P = 0.16), anticonvulsant use ( P = 0.35), type of postoperative immobilization ( P = 0.40), GMFCS level ( P = 0.31), or blade plate size ( P = 0.17). Only surgeon volume significantly related to periprosthetic fracture (odds ratio = 5.03, 95% CI: 1.53, 16.56, P = 0.008), with the highest-volume surgeon also using smaller blade plates ( P < 0.01). CONCLUSIONS: Periprosthetic fractures after VDRO surgery in children with CP are uncommon, and routine hardware removal appears unnecessary. The data suggest that the common dogma of putting in the largest blade plate possible to maximize fixation may increase the risk of periprosthetic fracture. Due to the overall low fracture rate, especially when contextualized relative to the risk of hardware removal, a reactive approach to hardware removal appears warranted. LEVEL OF EVIDENCE: Level III-retrospective study (targeting varus derotational osteotomies in children with cerebral palsy).

Fewer Dislocations After Total Hip Arthroplasty With Robotic Assistance or Fluoroscopic Guidance.

BACKGROUND: Computer navigation and robotic assistance may reduce total hip arthroplasty (THA) dislocations by improving the accuracy and precision of component positioning. We investigated dislocation rates for THAs using conventional techniques, robotic assistance, and computer navigation, while controlling for surgical approach, dual mobility (DM) use, and fluoroscopic guidance. METHODS: We reviewed 11,740 primary THAs performed between June 2016 and December 2022, including 5,873 conventional, 1,293 with robotic-arm assistance, and 4,574 with navigation. The approach was posterior in 6,580 (56.0%), anterior in 4,342 (37.0%), and lateral in 818 (7.0%). A DM was used in 10.4%. Fluoroscopy was used in 3,653 cases and only with the anterior approach. Multivariate analyses yielded odds ratios (OR) for dislocation and revision. Additional regression analyses for dislocation were performed for approach and DM. RESULTS: Raw dislocation rates were as follows: conventional 1.2%, robotic 0.4%, navigation 0.9%, anterior with fluoroscopy 0.4%, anterior without fluoroscopy 2.3%, posterior 1.3%, and lateral 0.5%. Upon multivariate analysis, use of robotics was found to be associated with significantly reduced dislocation risk compared to conventional (OR: 0.3), as did anterior (OR: 0.6) compared to posterior approach; navigation and lateral approach were not found to be associated with a significant reduction in risk. For the anterior approach, multivariate analysis demonstrated that fluoroscopy significantly reduced dislocation risk (OR: 0.1), while DM, robotics, and navigation were not significant. For the posterior approach, the dislocation risk was lower with robotics than with conventional (OR: 0.2); the use of navigation or DM did not demonstrate a significant reduction in risk. CONCLUSIONS: The use of robotics was associated with a reduction in dislocations for this cohort overall. Further, fluoroscopy in the anterior approach and robotic assistance in the posterior approach were both associated with decreased dislocation risk. The role of imageless computer navigation and DM implants requires further study.

Acute Total Hip Arthroplasty Following Acetabular Fracture is Associated With a High Risk of Revision, Dislocation, and Periprosthetic Fracture.

BACKGROUND: The aim of this study was to compare outcomes between acute, subacute, and delayed arthroplasty for acetabular fractures occurring within 1 week, from 1 week to 6 months, or more than 6 months before the index total hip arthroplasty (THA), versus THA without a history of acetabular fracture as a control. METHODS: We analyzed the records of patients undergoing primary THA who were enrolled in a national database for at least 2 years before and after the index procedure. Patients who had an initial diagnostic code for acetabular fracture occurring less than 1 week, from 1 week to 6 months, or at least more than 6 months before the THA were classified as acute THA (aTHA), subacute THA (saTHA), or delayed THA (dTHA), respectively. The control group was patients undergoing THA who did not have a history of acetabular fracture. There were 430,349 control primary THAs, 462 aTHAs, 675 saTHAs, and 1,162 dTHAs. RESULTS: After adjusting for age, sex, region, and comorbidities, patients who had an aTHA and saTHA experienced statistically significant increased odds of revision, dislocation, and periprosthetic fracture compared to primary THA without a history of acetabular fracture. Similarly, dTHA was associated with increased odds of revision, dislocation, and periprosthetic fractures compared to primary THA. In the multivariate analysis, aTHA had statistically significant higher rates of dislocation when compared to dTHA. CONCLUSIONS: Patients who had a history of acetabular fractures undergoing aTHA, saTHA, or dTHA have significantly increased rates of revision, periprosthetic fracture, and dislocation compared to primary THA in those who did not have a history of acetabular fractures.

Importance of hip capsular repair in total hip arthroplasty (THA) via the posterior lateral approach: a five year retrospective cohort study.

PURPOSE: This study aims to assess the impact of repairing the hip joint capsule during posterior-lateral approach total hip arthroplasty (THA) on postoperative hip joint function and late dislocation incidence. METHODS: A retrospective cohort study included 413 patients, divided into experimental (hip joint capsule repair, n = 204) and control (hip joint capsule excision, n = 209) groups. Patients were followed for five years, evaluating postoperative hip range of motion (ROM), dislocation rate, VAS and HHS scores, inflammatory and coagulation markers, hospitalization, blood loss, and body composition. Statistical analysis included the Student's t-test, Chi-square test, and logistic regression for dislocation risk factors. RESULTS: Joint capsule repair improved postoperative hip flexion and extension within six months and at two years postoperatively, internal and external rotation within three months, and abduction and adduction throughout the entire follow-up period (P < 0.05). Capsular repair also reduced early and late dislocation rates (P < 0.05). Significant differences in HHS and VAS scores, inflammatory and coagulation indicators, hospitalization, blood loss, and body composition were noted (P < 0.05). Multivariate logistic regression indicated hip joint repair, rheumatoid arthritis, epilepsy, and sarcopenia as dislocation risk factors (P < 0.05). CONCLUSIONS: Capsular repair during posterior-lateral THA improves postoperative hip function and mobility while reducing dislocation rates, blood loss, pain, inflammation, and economic burden. Patients with rheumatoid arthritis, epilepsy, or sarcopenia require individualized planning and enhanced postoperative care to minimize complications.

The "true" 1-year incidence of dislocation after primary total hip arthroplasty: validation of an algorithm identifying dislocations in the Danish National Patient Register based on 5,415 patients from the Danish Hip Arthroplasty Register.

BACKGROUND AND PURPOSE: Dislocations continue to be a serious complication after primary total hip arthroplasty (THA). Our primary aim was to report the "true" incidence of dislocations in Denmark and secondarily to validate a previously developed algorithm designed to identify THA dislocations in the updated version of the Danish National Patient Register (DNPR), based on data from the Danish Hip Arthroplasty Register (DHR). METHODS: We included 5,415 primary THAs from the DHR performed from July 1 to December 31, 2019. Version 3 of the DNPR was launched in February 2019, and a combination of data from the DNPR and a comprehensive national review of 1,762 hospital contacts enabled us to identify every dislocation occurring during the 1st year after THA to determine the "true" 1-year incidence of dislocation. The results were presented as proportions with 95% confidence intervals (CI), and validation was performed by calculating sensitivity and predictive values. RESULTS: The "true" 1-year incidence of dislocation was 2.8% (CI 2.4-3.3). Of these, 37% suffered recurrent dislocations during the follow-up period. Between-hospital variation ranged from 0.0% to 9.6%. The algorithm demonstrated a sensitivity close to 95%, while maintaining a positive predictive value of above 94%. CONCLUSION: The "true" 1-year incidence of dislocation of 2.8% is comparable to earlier findings, and large variation among hospitals continues to be evident. We have proven the algorithm to be valid in the latest DNPR (version 3), enabling it to be employed as a new quality indicator in future annual DHR reports.

Discontinuing the recommendation of hip precautions does not increase the risk of early dislocation after primary total hip arthroplasty using 36-mm heads: a population-based study from the Danish Hip Arthroplasty Register.

BACKGROUND AND PURPOSE: Dislocation is a severe complication following total hip arthroplasty (THA). Hip precautions have been recommended in the initial postoperative period but evidence supporting this practice is limited. We therefore conducted a population-based study to evaluate the association between discontinuing recommending postoperative hip precautions and the risk of early dislocation. METHODS: This is a cohort study with data from the Danish Hip Arthroplasty Register and the Danish National Patient Register. We included patients who underwent primary THA for osteoarthritis in 2004-2019 in public hospitals in the Capital Region of Denmark. The cohort was divided into the hip precautions group, comprising patients operated on between 2004 and 2009, and the no-precautions group operated on between 2014 and 2019. The primary outcome was the difference in the absolute risk of dislocation within 3 months post-surgery. The secondary outcome assessed the same risk within 2 years. We evaluated the difference in absolute risk using absolute risk regression (ARR). RESULTS: The cumulative incidence of dislocation within 3 months was 2.9% (confidence interval [CI] 2.5-3.3) in the hip precautions group and 3.5% (CI 3.1-3.9) in the no-precautions group. The risk of dislocation was higher in the no-precautions group but failed to reach statistical significance in the crude (ARR 1.2, CI 0.9-1.6) and multivariate model (ARR 1.4, CI 0.9-2.2). CONCLUSION: We found a higher but statistically insignificant increase in the risk of early dislocation in the no-precautions group. The lack of significance in the association may be explained by the increased use of 36-mm femoral heads after the guideline revision.

The relationship between hip displacement, scoliosis, and pelvic obliquity in 106 nonambulatory children with cerebral palsy: a longitudinal retrospective population-based study.

BACKGROUND AND PURPOSE: The relationship between hip displacement (HD), pelvic obliquity (PO), and scoliosis in nonambulatory children with cerebral palsy (CP) has not been clearly elucidated. The aims of this population-based study were to examine the prevalence and temporal sequence of these deformities in nonambulatory children with CP and to evaluate how probable it is that severe unilateral HD contributes to development of scoliosis. PATIENTS AND METHODS: This longitudinal study comprised 106 nonambulatory children, enrolled in a surveillance program. Pelvic radiographs for measurements of migration percentage (MP) and PO were taken once a year from the diagnosis of HD. Spine radiographs were taken in patients with clinically detected scoliosis. Radiographic follow-up continued until skeletal maturity. RESULTS: Clinically significant scoliosis (Cobb angle ≥ 40°) occurred in 60 patients at a mean age of 11.8 years. 65 patients developed clinically significant HD (MP ≥ 40%) at a mean age of 4.8 years. 24 patients had no significant hip or spine deformities, 22 had HD only, 17 had scoliosis only, and 43 had both deformities. HD was diagnosed before scoliosis in all except 1 of the patients with both deformities. 14 of 19 patients with severe unilateral HD (MP ≥ 60%) had scoliosis convexity to the opposite side of the displaced hip. CONCLUSION: The combination of scoliosis and HD was frequent, and HD was diagnosed first in almost all the patients. HD might be a contributory cause of scoliosis in patients with severe, unilateral HD, PO, and later scoliosis with convexity to the opposite side.

Exploring the Relationship between Cerebral Palsy and Hip Dysplasia: Insights from the National Inpatient Sample.

Background and Objective: Cerebral palsy (CP) significantly impacts quality of life globally. Hip dysplasia (HD) is a common musculoskeletal issue in CP patients. This study investigates the prevalence, risk factors, and impact of HD on CP patients using a large national database. Materials and Methods: Data from the National Inpatient Sample (NIS) database (2016-2019) were used, identifying CP and HD diagnoses through ICD-10 codes. Baseline characteristics were tabulated. Univariate and multivariate logistic regression analyses examined predictors of HD development in CP patients, presenting data as odds ratios (ORs) with 95% confidence intervals (CIs). Results: Among 3,951,040 pediatric patients, 28,880 had CP (27,466 without HD, and 1414 with HD), and 3,922,160 did not have CP. CP significantly increased the likelihood of developing HD in univariate (OR = 35.03, 95% CI [33.01, 37.17], p < 0.0001) and multivariate (OR = 26.61, 95% CI [24.94, 28.40], p < 0.0001) analyses. Among patients with CP, race was significantly associated with HD, with ORs below 1 for all racial categories compared to Whites. Females had nearly twice the odds of HD compared to males (OR = 1.96, 95% CI [1.86, 2.05], p < 0.0001). Age was significantly associated with HD, with each additional year increasing the odds (OR = 1.03, 95% CI [1.026, 1.034], p < 0.0001). Individuals in the high 51st-75th income quartile had a 17% increase in the odds of HD (OR = 1.17, 95% CI [1.09, 1.25], p < 0.0001) compared to the low 1st-25th income quartile. Conclusions: This study reinforces the strong association between CP and HD, highlighting the need for further research and prospective studies to validate these findings.

Impact of previous lumbar spine surgery on total hip arthroplasty and vice versa: How long should we be concerned about mechanical failure?

INTRODUCTION: This registry study aims to assess the prevalence and demographic characteristics of patients with lumbar spine (LS) surgical procedures who undergo total hip arthroplasty (THA), to compare the long-term survival and causes of failure of THA in patients who previously underwent LS fusion and non-fusion surgical procedures, and to evaluate the risk of undergoing a revision LS surgery after THA. MATERIALS AND METHODS: Patients who underwent LS surgery followed by THA were identified by cross-referencing data from the Orthopedic Prosthetic Implants Registry and the Regional Hospital Discharge Database. Three groups of THA patients were identified: patients who underwent previous lumbar surgery with fusion (LS fusion-THA), without fusion (LS non-fusion-THA), and a control group with only THA (No LS surgery-THA). Demographic data, THA survival, number and causes of failure, and data on revision procedures on THA and LS were collected. RESULTS: Of the total of 79,984 THA, 2.2% of patients had a history of LS procedures. THA only patients showed better results, while patients in the LS fusion-THA group had worse implant survival at 5-year follow-up. In the LS fusion-THA and LS non-fusion-THA, mechanical THA failures were more frequent in the first two years after implantation. There were no differences between groups regarding the risk of undergoing LS revision surgery. CONCLUSIONS: LS surgery negatively affects THA survivorship. In patients who previously underwent LS fusion and non-fusion surgical procedures, most THA failure occurs in the first two years after implant. The study contributes to the understanding of the relationship between the hip and the LS and provides useful guidance for clinical practice.

A Meta-Analysis of the Incidence and Temporal Trends of Postoperative Dislocation in Revision Total Hip Arthroplasty Utilizing Constrained Acetabular Components or Dual Mobility Implants.

BACKGROUND: The incidence of dislocation after revision total hip arthroplasty (rTHA) is reported to be up to 25% and remains a common source of failure. Constrained acetabular components and dual mobility implants are two implant classes being utilized to alleviate this burden in patients who have recurrent instability or major intraoperative instability. This meta-analysis evaluated the incidence and temporal trends of dislocation after implantation with constrained acetabular components and dual mobility implants in rTHA. METHODS: Longitudinal studies reporting dislocation after the use of constrained acetabular components or dual mobility implants in rTHA were sought from Medline and Embase to October 2022. Secondary outcomes included re-revision surgery for dislocation and all causes. A total of 75 relevant citations were identified comprising 36 datasets of 3,784 constrained acetabular components and 47 datasets of 10,216 dual mobility implants. RESULTS: For constrained acetabular components, the pooled incidence of dislocation was 9% (95% confidence interval: 7.2, 11.7) (range 0.0%-35.3%) over a weighted mean follow-up of 6 years, in contrast to 3% (95% confidence interval: 2.2, 4.4) (range 0.0%-21.4%) over 5 years for dual mobility implants. Re-revision rates for dislocation after using constrained acetabular components were around 9%, in contrast to 2% for dual mobility implants. Re-revision rates for all causes after using constrained acetabular components were around 19%, in contrast to 8% for dual mobility implants. CONCLUSION: Dual mobility implants in the context of rTHA demonstrate lower incidences of dislocation (3% versus 9%), re-revision for dislocation (2% versus 9%), and rer-evision for any cause (8% versus 19%) in contrast to constrained acetabular components. This must be considered by surgeons when implanting such devices, often selected to treat instability.