One-third of Hips After Periacetabular Osteotomy Survive 30 Years With Good Clinical Results, No Progression of Arthritis, or Conversion to THA

Total Hip Arthroplasty in Challenging Settings: Acetabular Fractures, Adolescents, Conversions, and Developmental Dysplasia of the Hip

Total hip arthroplasty (THA) is one of the most common and successful procedures for the treatment of end-stage hip arthritis. However, in certain complex scenarios, THA can present important and unique challenges, specifically following acetabular fractures in adolescent patients, following failed fixation of proximal femoral fractures, and in developmental dysplasia of the hip (DDH). As these cases involve distorted anatomy, poor bone quality, retained hardware, and previous surgeries, detailed planning, specialized instrumentation and implants, and novel surgical techniques are required. This narrative review examines the challenges, surgical considerations, outcomes, and complications in complex THA management.

Total hip arthroplasty in adolescent patients delivers large improvements in hip function and quality of life : a single-centre cohort study with up to 34 years of follow-up

Aims

The aim of this study was to report the implant survival, quality of life, and patient-reported outcome measures (PROMs) in a cohort of adolescent patients who underwent total hip arthroplasty (THA).

Methods

This was retrospective review of all adolescent patients treated with THA in a single centre. Survival was estimated using the Kaplan-Meier method. Hip-specific PROMs included the Oxford Hip Score (OHS) and the modified Harris Hip Score (mHHS). Health-related quality of life was recorded using the EuroQol five-dimension three-level questionnaire (EQ-5D-3L) and a subjective health assessment using a visual analogue scale.

Results

A total of 68 THAs were undertaken in 49 patients with a median age of 16 years (IQR 10 to 19), between April 1971 and April 2023. The median follow-up for the assessment of survival in the whole cohort was 4.6 years (IQR 1.4 to 8.9). The cumulative incidence of revision was 10.0% (95% CI 0.0 to 20.8) at ten years, 29.1% (95% CI 4.1 to 47.5) at 15 years, 36.2% (95% CI 8.0 to 55.7) at 20 years, and 45.3% (95% CI 12.1 to 65.9) at 30 years. The mean index value derived from the EQ-5D-3L, which was available in 15 patients (21 THAs), improved from -0.35 (SD 0.28) to 0.71 (SD 0.33) at a median follow-up of 1.5 years (IQR 0.5 to 2.0). The median OHS improved from 10 (IQR 7 to 16) preoperatively to 45 (IQR 37 to 48), and the median mHHS improved from 28 (IQR 16.25 to 32.75) to 84 (IQR 63 to 91), at a median follow-up of 1.3 years (IQR 0.5 to 2.3).

Conclusion

Adolescent patients with severe symptoms from the hip have some of the worst possible states of health which are encountered in orthopaedic surgery. THA is an effective form of treatment for hip conditions in children, with a higher than normal incidence of revision surgery. The socioeconomic benefits of THA need further investigation to establish guidelines for the treatment of children with severe symptoms from the hip.

Periacetabular Osteotomy Leads to Improved Long-term Patient-reported Outcomes: A Systematic Review

BACKGROUND

Periacetabular osteotomy (PAO) has shown favorable outcomes. The goal of this study was to conduct a systematic review to assess the reoperation rates and long-term patient-reported outcomes (PROs) of PAO for the treatment of hip dysplasia.

MATERIALS AND METHODS

A systematic review was conducted. Studies that reported PROs with a minimum mean of 10-year follow-up were included.

RESULTS

The 8 studies (984 hips) that were included reported a significant improvement between preoperative and postoperative PROs.

CONCLUSION

Patients who underwent PAO surgery showed significant improvement in PROs at a minimum mean 10-year follow-up. [Orthopedics. 2025;48(3):e113-e123.].

From mobility to intimacy: assessing the effects of periacetabular osteotomy on sexual function in patients with hip dysplasia

Aims

Developmental dysplasia of the hip (DDH) often leads to early osteoarthritis, causing pain and functional limitations that may impair sexual function. This study investigates the impact of periacetabular osteotomy (PAO) on sexual function in DDH patients, assessing changes from preoperative impairments to postoperative improvements.

Methods

This retrospective study analyzed data from DDH patients treated with PAO between January 2015 and June 2017 at a single orthopaedic university centre. Data included radiological parameters and patient-reported outcome measures: International Hip Outcome Tool (iHOT-12), Subjective Hip Value, Hip disability and Osteoarthritis Outcome Score (HOOS) and its sub-scores, and Numeric Pain Scale. Sexual function was specifically assessed using iHOT-12 item nine, asking, "How much trouble do you have with sexual activity because of your hip?"

Results

The study included 120 hips in 107 patients, predominantly female (85.1%). Radiological improvements post PAO were significant, with increases in the lateral centre-edge angle (LCEA) (16.6° (SD 6.0°) to 29.4° (SD 5.8°); p < 0.001) and reductions in the Tönnis angle (13.3° (SD 6.7°) to 1.2° (SD 7.4°); p < 0.001). Patient-reported outcomes demonstrated significant improvements postoperatively. Specifically, the iHOT-12 sexual function item showed substantial improvement from a mean preoperative score of 54.3 (SD 33.7) to a postoperative score of 75.0 (SD 27.1) (p < 0.001). Females reported significant enhancements in sexual function (p < 0.001), whereas improvements in males did not reach statistical significance (p = 0.181). Cases of under-correction (LCEA < 25°) demonstrated significantly higher impairments in sexual function postoperatively compared with adequately corrected cases, indicating the importance of achieving optimal anatomical correction.

Conclusion

PAO significantly enhances sexual function and overall hip-related quality of life in patients with symptomatic DDH. The findings underscore the necessity of precise surgical techniques and highlight that outcomes may vary by sex, suggesting a need for a sex-sensitive approach in both clinical practice and research.

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

PURPOSE

To assess patient-reported outcomes (PROs), clinically significant outcomes (CSOs), and survivorship after staged hip arthroscopy with labral repair, femoroplasty, and capsular plication followed by periacetabular osteotomy (PAO) for the management of femoroacetabular impingement syndrome and hip dysplasia (lateral center-edge angle ≤25°).

METHODS

A prospectively maintained database was queried to retrospectively identify patients who underwent staged primary hip arthroscopy and PAO between January 2018 and October 2021 and had a minimum 2-year follow-up. PROs collected included Hip Outcome Score Activities of Daily Living/Sports Subscale, international Hip Outcome Tool-12 item questionnaire, and visual analog scale for pain. CSO achievement for minimal clinical important difference and patient acceptable symptom state was determined through cohort-specific thresholds. Rates of reoperation, including, revision hip arthroscopy, and conversion to total hip arthroplasty were evaluated to determine short-term survivorship.

RESULTS

Thirty-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 < .001). Patients demonstrated a significant improvement in all PROs pre- to postoperatively (P0. ≤ .004). Minimal clinical important difference and patient acceptable symptom state achievement rates for any PRO were 93.9% and 78.8%, respectively. There were no revision hip surgeries or conversion to total hip arthroplasty 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.

CONCLUSIONS

Staged 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.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Periacetabular Osteotomy Improves Hip Microinstability Between Supine and Standing Radiographs in Symptomatic Hip Dysplasia

Background

Whether periacetabular osteotomy (PAO) improves hip microinstability in patients with symptomatic hip dysplasia remains poorly understood.

Purpose

To assess the femoral head translation with static postural change, considered a potential indicator of hip microinstability, comparing dysplastic hips before and after PAO with normal hips.

Study Design

Descriptive laboratory study.

Methods

A total of 26 patients (30 hips) with hip dysplasia underwent PAO, and 18 healthy individuals (18 hips) were eligible. Using a 3-dimensional-to-2-dimensional registration technique, femoral head translation before and after PAO was quantified as the displacement of the center of the femoral head relative to the center of the acetabulum between supine and standing positions. Morphological factors on supine anteroposterior pelvic radiographs before and after PAO correlated with the femoral head translation, particularly lateral translation, were examined.

Results

Femoral head translation decreased after PAO (1.5 ± 0.4 mm vs 1.0 ± 0.4 mm; P < .001) but remained larger than in controls (1.0 ± 0.4 mm vs 0.7 ± 0.3 mm; P = .01). The more severe the hip dysplasia before PAO was, the greater the femoral head translation. However, the femoral head translation improved after PAO with sufficient acetabular correction. The acetabular roof obliquity (ARO) showed the strongest correlation with lateral translation of the femoral head from the supine to standing position before PAO. In contrast, no correlation was found after PAO.

Conclusion

This study demonstrates that the severity of hip dysplasia influences hip microinstability, that PAO mitigates hip microinstability with adequate acetabular correction, and that PAO does not normalize hip stability because of residual joint incongruity. In patients with a larger ARO, the femoral head has more lateral translation in the standing position. Therefore, weightbearing postural radiographs are crucial for understanding hip biomechanics in hip dysplasia and refining surgical corrections during PAO.

Clinical Relevance

PAO can make the hip more stable in hip dysplasia, but not as stable as the normal hip. In hip dysplasia, pre-PAO standing radiographs should be evaluated due to their accurately representing the femoral head position relative to the acetabulum.

A Novel System for Markerless Intra-Operative Bone and Bone Fragment Tracking

Fluoroscopic guidance is an integral tool in modern orthopedic surgery often used to track bones and/or bone fragments during a surgical procedure. However, relying upon this intra-operative 2D projective imaging modality for this purpose can challenge a surgeon's ability to interpret 3D position and orientation of any but the simplest bony anatomy. A number of object-tracking technologies have been developed to aid surgeons, but they have failed to be generalizable to a wider array of procedures, have required an unrealistic amount of time and effort to implement, or have unacceptably changed the flow of the surgery. This work describes a novel, general-purpose system for markerless, intra-operative bone tracking that seamlessly integrates into a surgical setting. The system uses a unique calibration object placed next to the patient, which provides a common reference for aligning multiple fluoroscopic images. This approach enables robust and expedient 3D object registration from only two semi-orthogonal 2D fluoroscopic images.

Sexual function and pregnancy outcomes after periacetabular osteotomy: a systematic review

Periacetabular osteotomy (PAO) is a surgical treatment of developmental dysplasia of the hip (DDH). This systematic review investigates the impact PAO has on sexual function and pregnancy through changes in patient-reported outcomes. A literature search of Medline, PubMed, EMBASE, and the Cochrane Library from 1996 to November 2023 was performed. Search terms included: 'periacetabular osteotomy', 'pelvic osteotomy', 'outcomes', 'sexual function', 'pregnancy', and 'childbirth'. Assessment of methodological quality was performed using the methodological index for nonrandomized studies (MINORS) criteria and Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) system. The search returned 560 papers, with 5 meeting the inclusion criteria. Sexual function improved over both short- and longer-term follow-up periods. 48.2% of patients had improved sexual function following PAO. Female patients reported greater improvement than males, who had a higher baseline score. No complications were documented in pregnancy or delivery compared to patients who had not had a PAO. Increased rates of caesarean sections (CSs) were seen in all studies (37.4%) compared to the European average. All five papers were calculated to be of low quality according to the MINORS criteria and low certainty according to the GRADE level of evidence. Patients receiving a PAO due to symptomatic DDH had improved sexual dysfunction due to a reduction in hip pain, but almost half of these patients may not appreciate any benefit. There is an increased likelihood of CS in patients post-PAO, with no reliable evidence for its necessity. Limitations of this review included poor quality and availability of evidence, as all studies were retrospective cohort studies. Further larger powered studies are required to assess the full impact of PAO on both sexual function and pregnancy.

Can We Enhance Shared Decision-making for Periacetabular Osteotomy Surgery? A Qualitative Study of Patient Experiences

BACKGROUND

Periacetabular osteotomy (PAO) surgery presents an opportunity for shared decision-making (SDM) and may be facilitated by decision-making tools. Currently, no diagnosis or treatment-specific decision-making tools exist for this patient population. Understanding patient PAO surgery decision-making experiences and processes would enable development of a treatment-specific decision-making tool and would help hip preservation surgeons with SDM practices.

QUESTIONS/PURPOSES

Qualitative methodology was used to address the following questions: (1) What were the information support needs of adult patients with hip dysplasia who decided to have PAO? (2) What was important to adult patients with hip dysplasia who decided to have PAO? (3) How did adult patients with hip dysplasia who have undergone PAO experience the surgical decision-making process? (4) What elements of SDM did adult patients with hip dysplasia experience with their surgeons when deciding to have PAO?

METHODS

Fifteen volunteer, English-speaking patients in the United States who had been diagnosed with hip dysplasia and who had undergone PAO surgery 6 to 12 months prior to the study were recruited through five PAO surgery Facebook support groups. Individuals were excluded if they had an underlying neuromuscular condition or other diagnosis related to nondevelopmental dysplasia of the hip or if they had a previous PAO surgery > 12 months before data collection. We used purposive sampling strategies to promote sample heterogeneity based on age and preoperative activity level, as these are characteristics that may impact decision-making. Participants were categorized into three age groups: 20 to 29 years, 30 to 39 years, and ≥ 40 years. Participants were also categorized as having "low activity," "moderate activity," or "high activity" preoperatively based on self-reported University of California Los Angeles (UCLA) Activity Scale scores. Participants were enrolled consecutively if they met the inclusion criteria and fulfilled one of our sampling categories; we had plans to enroll more participants if thematic saturation was not achieved through the first 15 interviews. Participants included 14 women and one man ranging in age from 23 to 48 years, and all had undergone PAO surgery for hip dysplasia 6 to 12 months prior to the interview. One-on-one semistructured interviews were conducted with each participant by a single interviewer through Zoom video conferencing using video and audio recording. Participants answered semistructured interview questions and provided verbal responses to survey questions so researchers could gain demographic information and details about their symptoms, diagnosis, and PAO surgery between June 2021 and August 2021. Quantitative survey data were analyzed using descriptive statistics. Qualitative data were analyzed by three researchers using principles of reflexive thematic analysis. Candidate themes were iteratively defined and redefined until central themes were developed that were distinctly different, yet centrally relevant, and answered the research questions. All codes that informed category and theme development were generated within the first six transcripts that were analyzed. The team felt that thematic saturation was established with the 15 interviews.

RESULTS

The main information needs for adult patients with hip dysplasia included diagnosis and treatment-related information, as well as logistics related to surgery and recovery. Many patients described that their information needs were only partially met by their surgeon; most engaged in additional information-seeking from scientific research and online resources and relied on patient peers to meet information needs about the lived experience and logistics related to surgery and recovery. It was important to patients that PAO surgery could preserve their native hip or delay THA and that PAO surgery was likely to reduce their pain and improve function; decision-making was facilitated when patients were able to identify how the indications and goals of PAO surgery aligned with their own situation and goals for surgery. Patients' experiences with decision-making were more positive when information needs were met, when indications and goals for PAO surgery aligned with their personal values and goals, and when their preferred and actual decision-making roles aligned. Adult patients with hip dysplasia described high variability in the extent to which patients were invited to share personal preferences, values, and goals around PAO surgery and the extent to which preferred patient decision-making roles were assessed.

CONCLUSION

We found that elements of SDM are not consistently integrated into hip preservation practice. The knowledge gained through this work about patient PAO surgery information needs, what matters to patients when deciding to have surgery, and their experiences with PAO surgery decision-making can inform future PAO surgery decision-making tool development. Future studies are needed to validate the findings of this study and to determine whether they are generalizable to adult patients with hip dysplasia with different demographic characteristics or to patients who do not participate in social media support groups.

CLINICAL RELEVANCE

Surgeons should recognize that patients are likely to leave their office without their information needs being met. SDM strategies can promote more effective information exchanges in the clinic so surgeons can help patients identify their information needs, provide education and direction to accurate and reputable resources to meet those needs, and help patients appraise information they gather and apply it to their personal situation. Hip preservation surgeons can use the sample SDM script and checklist offered here to support adult patients with hip dysplasia who are making PAO surgery decisions until a future diagnosis and treatment-specific decision-making tool is available.

A Computer Modeling-Based Target Zone for Transposition Osteotomy of the Acetabulum in Patients with Hip Dysplasia

BACKGROUND

This study aimed to determine the acetabular position to optimize hip biomechanics after transposition osteotomy of the acetabulum (TOA), a specific form of periacetabular osteotomy, in patients with hip dysplasia.

METHODS

We created patient-specific finite-element models of 46 patients with hip dysplasia to simulate 12 virtual TOA scenarios: lateral rotation to achieve a lateral center-edge angle (LCEA) of 30°, 35°, and 40° combined with anterior rotation of 0°, 5°, 10°, and 15°. Joint contact pressure (CP) on the acetabular cartilage during a single-leg stance and simulated hip range of motion without osseous impingement were calculated. The optimal acetabular position was defined as satisfying both normal joint CP and the required range of motion for activities of daily living. Multivariable logistic regression analysis was used to identify preoperative morphological predictors of osseous impingement after virtual TOA with adequate acetabular correction.

RESULTS

The prevalence of hips in the optimal position was highest (65.2%) at an LCEA of 30°, regardless of the amount of anterior rotation. While the acetabular position minimizing peak CP varied among patients, approximately 80% exhibited normalized peak CP at an LCEA of 30° and 35° with 15° of anterior rotation, which were the 2 most favorable configurations among the 12 simulated scenarios. In this context, the preoperative head-neck offset ratio (HNOR) at the 1:30 clock position (p = 0.018) was an independent predictor of postoperative osseous impingement within the required range of motion. Specifically, an HNOR of <0.14 at the 1:30 clock position predicted limitation of required range of motion after virtual TOA (sensitivity, 57%; specificity, 81%; and area under the receiver operating characteristic curve, 0.70).

CONCLUSIONS

Acetabular reorientation to an LCEA of between 30° and 35° with an additional 15° of anterior rotation may serve as a biomechanics-based target zone for surgeons performing TOA in most patients with hip dysplasia. However, patients with a reduced HNOR at the 1:30 clock position may experience limited range of motion in activities of daily living postoperatively.

CLINICAL RELEVANCE

This study provides a biomechanics-based target for refining acetabular reorientation strategies during TOA while considering morphological factors that may limit the required range of motion.

Borderline Hip Dysplasia - Best Treated with Hip Arthroscopy or Periacetabular Osteotomy?

PURPOSE OF REVIEW

As the field of hip preservation evolves, the diagnosis of borderline dysplasia (defined as a lateral center edge angle between 18°-25°) has shown itself to be one of the more challenging diagnoses to treat. As the nuances of acetabular coverage have come to light, the question of whether borderline hip dysplasia is best treated with isolated hip arthroscopy, periacetabular osteotomy, or whether a combined procedure is best, is now top of mind. The goal of these procedures is to not only improve patient symptoms, but to correct underlying pathology and ideally slow the development of hip osteoarthritis. The purpose of this review is to summarize the recent literature and clinical findings regarding both isolated hip arthroscopy and periacetabular osteotomy in the surgical management of borderline hip dysplasia.

RECENT FINDINGS

Current research demonstrates improved postoperative clinical outcome scores for both patients who had isolated hip arthroscopy in the setting of borderline hip dysplasia and for those patients who underwent periacetabular osteotomy. Mid-term outcomes for patients in both groups have showed low rates of conversion to total hip arthroplasty. No gold standard in the surgical management of borderline hip arthroscopy exists. Improved clinical outcomes have been seen postoperatively in patients who undergo hip arthroscopy and in patients who undergo periacetabular osteotomy. Successful clinical outcomes seem to rely on treatment of the underlying clinical pathology and are largely based on the appropriate surgical indications and appropriate surgical techniques. Surgical decision making in this patient population should be individualized based on a comprehensive evaluation of the patient.

Persistently elevated joint contact stress after periacetabular osteotomy is associated with joint failure at minimum 10-year follow-up

Periacetabular osteotomy (PAO) is a common treatment for prearthritic hip dysplasia. The goal of this investigation was to determine if computationally assessed hip contact mechanics are associated with joint failure at minimum 10-year follow-up. One hundred patients with hip dysplasia (125 hips) completed patient-reported outcomes an average of 13.8 years (range 10.0-18.0 years) after PAO. 63/125 hips were classified as having failed: 26 converted to total hip arthroplasty (THA) and 37 with significant disability indicated by modified Harris Hip Score (mHHS) ≤ 70. Differences in discrete element analysis-computed contact mechanics were compared between (1) preserved and failed hips, (2) preserved hips and hips that failed by THA, and (3) preserved hips and hips that failed by mHHS ≤ 70. Failed hips had significantly higher preoperative contact stress and exposure metrics (p < 0.001-0.009) than preserved hips. Failed hips also had significantly higher postoperative peak contact stress (p = 0.018), higher mean contact stress (p < 0.001), and smaller contact area (p = 0.044). When assessed based on type of failure, hips that failed by THA had significantly higher postoperative contact stress and exposure metrics than preserved hips (p < 0.001-0.020). In hips that failed by mHHS ≤ 70, mean postoperative contact stress exposure was significantly higher compared to preserved hips (p = 0.043). Despite improved radiographic measures of dysplasia after PAO, pathologic joint contact mechanics can persist and predict treatment failure at minimum 10 years after surgery. Operative and nonoperative techniques specifically intended to reduce harmful contact mechanics in dysplastic hips may have the potential to further improve clinical outcomes after PAO.

Mid to long-term survivorship of hip arthroplasty in patients 40 years and younger

BACKGROUND

Etiology of hip osteoarthritis (OA) and survival of hip arthroplasty in the young (below 40-years-old) remains poorly described. Furthermore, joint survivorship mid to long-term and PROMs according to the etiology are unclear. The study aims were to 1) identify the indications for arthroplasty in the below 40-years-old cohort; 2) define hip arthroplasty outcomes in the young and 3) test whether patients with sequelae of pediatrics hip disease have inferior outcome compared to other patients.

HYPOTHESIS

Our hypothesis was that hip arthroplasty is a viable option for managing hip disease in patients under 40, with excellent survival rates and outcomes.

MATERIAL AND METHODS

This is an IRB approved, retrospective, consecutive, multi-surgeon, cohort study from a single academic center. Indication for hip arthroplasty of 346 patients (410 hips) below 40-years-old were studied; 239 underwent THA (58%) and 171 hip resurfacing (42%). Patient, surgical and implant factors were tested for association with implant survivorship and functional outcome for hip arthroplasty performed with a follow-up of more than two years. Pediatric hip sequelae patients were compared for survival and PROMs with the rest of the cohort.

RESULTS

The most common etiology of OA was FAI (47%), followed by pediatric hip sequelae (18%). The 10-year survivorship was 97.2% ± 1.2, mean OHS was 45.1 ± 6.3 and mean HHS was 93.4 ± 12.6. The pediatric hip sequelae subgroup demonstrated no differences in 10-year survivorship and better PROMs compared to rest (OHS: 46.6 ± 3.8; HHS: 96.0 ± 8.5).

DISCUSSION

The most common aetiologies amongst the young with hip OA is FAI and pediatric hip sequelae. Hip arthroplasty in the young presents excellent 10-year survivorship and PROMs. Excellent survival and PROMs in the young with pediatric hip sequelae provide important information for decision-making in this challenging population.

LEVEL OF EVIDENCE

III; retrospective cohort study.

Understanding recurrent groin pain following periacetabular osteotomy: assessment of psoas tendon mechanics using discrete element analysis

Recurrent groin pain following periacetabular osteotomy (PAO) is a challenging problem. The purpose of our study was to evaluate the position and dynamics of the psoas tendon as a potential cause for recurrent groin pain following PAO. A total of 386 PAO procedures, performed between January 2013 and January 2020, were identified from a single surgeon series. Thirteen patients (18 hips) had a psoas tendinopathy, as confirmed with relief of symptoms following a diagnostic injection into the psoas tendon. All patients underwent computed tomography (CT) scans pre- and post-operatively. The data from CT scan was used to manually segment bony structures and create 3D models using Mimics software (Materialise NV). A validated discrete element analysis model using rigid body springs was used to predict psoas tendon movement during hip circumduction and walking. The distance of the iliopsoas tendon to any bony abnormality was calculated. All computational analyses were performed using MATLAB software. Thirteen hips (13/18) showed bony malformations (spurs, hypertrophic callus or delayed union and malunion) secondary to callus at the superior pubic ramus. The mean minimal distance of the iliopsoas tendon to osteotomy site was found to be 13.73 mm (σ = 3.09) for spurs, 10.99 mm (σ = 2.85) for hypertrophic callus and 11.91 mm (σ = 2.55) for canyon type. In normal bony healing, the mean minimal distance was 18.55 mm (σ = 4.11). Using a validated computational modelling technique, this study has demonstrated three different types of malformation around the superior pubic osteotomy site, which are associated with psoas impingement. In all of the cases, the minimal distance of the iliopsoas tendon to the osteotomy site was reduced by 59-74%, as compared with the normal anatomy.

Deficient postoperative anterior wall index adversely affects joint survival after transposition osteotomy of the acetabulum in patients with hip dysplasia

Aims

This study aimed to determine clinical outcomes; relationships between postoperative anterior, lateral, and posterior acetabular coverage and joint survival; and prognostic factors for joint survival after transposition osteotomy of the acetabulum (TOA).

Methods

Data from 616 patients (800 hips) with hip dysplasia who underwent TOA between November 1998 and December 2019 were reviewed. The median follow-up period was 8.9 years (IQR 5 to 14). A medical notes review was conducted to collect demographic data, complications, and modified Harris Hip Score (mHHS). Radiological indicators of acetabular coverage included lateral centre-edge angle (LCEA), anterior wall index (AWI), and posterior wall index (PWI). The cumulative probability of TOA failure (progression to Tönnis grade 3 or conversion to total hip arthroplasty) was estimated using the Kaplan-Meier product-limited method. A multivariate Cox proportional hazards model was used to identify predictors for failure.

Results

Median mHHS improved from 68 preoperatively to 96 at the latest follow-up (p < 0.001). The overall joint survival rate was 97% at ten years and 70% at 20 years. For the postoperative LCEA subgroups, survival in the deficient group was lower than that in the excessive (p = 0.006) and normal (p = 0.007) groups. For the postoperative AWI subgroups, survival in the deficient group was lower than that in the excessive (p = 0.015) and normal (p < 0.001) groups. Multivariate analysis identified age (p = 0.010), Tönnis grade 2 (p < 0.001), roundness index (p = 0.003), fair joint congruity (p = 0.004), and postoperative AWI (p = 0.002) as independent risk factors.

Conclusion

Deficient postoperative AWI adversely affected joint survival after TOA, underscoring the importance of sufficient anterior acetabular coverage, along with precise surgical indications, to ensure successful hip joint preservation in the treatment of hip dysplasia.

The Principles of Hip Joint Preservation

The three primary factors involved in preservation of the hip joint include femoroacetabular impingement (FAI), hip dysplasia/instability, and femoral torsion abnormalities. Each of these factors affects the health of the acetabular labrum and femoroacetabular cartilage. The appropriate surgical treatments for each of these factors include arthroscopic or open femoroplasty/acetabuloplasty for FAI, periacetabular osteotomy for hip dysplasia/instability, and derotational femoral osteotomy for femoral torsion abnormalities. When evaluating patients with prearthritic hip conditions, orthopaedic surgeons should be aware of the various factors involved in hip joint preservation and, if surgery is indicated, the surgeon should be sure to address all factors that need surgical treatment rather than focusing on the commonly diagnosed issue or visible injury, for example, a labral tear. If any of these factors is ignored, the hip joint may not thrive. The purpose of this review was to explain the importance of the most common factors involved in hip joint preservation and the appropriate surgical treatments for pathology in these factors.

Staged Hip Arthroscopy and Periacetabular Osteotomy in Active Patients Aged 45 Years and Older Produce Comparable Improvements in Outcome Scores to Younger Patients

PURPOSE

To determine staged hip arthroscopy and periacetabular osteotomy (PAO) mid-term outcomes in active patients aged 45 years and older compared with a younger group.

METHODS

All patients aged 45 years and older who underwent staged arthroscopy and PAO between 2015 and 2021 were retrospectively analyzed and compared with a case-matched control group of younger patients. All patients underwent at least 6 months of nonoperative management prior to surgery. Prior to PAO, all patients underwent hip arthroscopy to address any intra-articular pathology. The experimental group consisted of patients with dysplasia aged 45 years and older without significant osteoarthritis who underwent PAO and reported patient-reported outcomes for a minimum of 1 year postoperatively. Patient-reported outcomes were quantified using the International Hip Outcome Tool 12 (iHOT-12) score and Non-arthritic Hip Score (NAHS).

RESULTS

The cohort consisted of 35 patients (44 hips) with a mean age of 49.4 ± 3.8 years. The lateral center-edge angle significantly improved from preoperatively (20.1° ± 4.5°) to postoperatively (33.2° ± 3.2°, P < .001). The mean follow-up period in the PAO cohort aged 45 years and older was 2.80 years (standard deviation, 1.3 years) postoperatively. Patients reported significant improvements in the iHOT-12 score (36.6 ± 14.1 preoperatively vs 81.2 ± 21.0 at latest follow-up, P < .001) and NAHS (59.2 ± 15.5 preoperatively vs 87.4 ± 13.1 at latest follow-up, P < .001). The older cohort did not report significantly different iHOT-12 scores compared with the control group at any point, and age did not significantly affect either outcome score (P > .05).

CONCLUSIONS

Patients aged 45 years and older reported a statistically significant improvement in hip function and pain after staged hip arthroscopy and PAO, with outcome scores comparable to a younger cohort. Our findings show that appropriately selected older patients with dysplasia without significant pre-existing hip osteoarthritis experience clinically meaningful improvements in hip pain and function after hip preservation surgery.

LEVEL OF EVIDENCE

Level III, retrospective, comparative case series.

Persistence of Labral Tears and Resolution of Paralabral Cysts With 2-Year Magnetic Resonance Imaging Analysis After Periacetabular Osteotomy for Hip Dysplasia

PURPOSE

To evaluate the labrum status and paralabral cysts on preoperative and postoperative magnetic resonance imaging (MRI) in patients with developmental dysplasia of the hip (DDH) who underwent periacetabular osteotomy (PAO).

METHODS

A retrospective review was conducted using prospectively collected data from patients who had undergone primary PAO between June 1, 2021, and May 30, 2022. Inclusion criteria were an age range of 16 to 55 years and a minimum follow-up of 2 years. MRI was used to evaluate the preoperative and postoperative conditions of the labrum and the presence of paralabral cysts. Furthermore, the correlations between the presence of paralabral cysts and demographic and radiographic variables were investigated. Additionally, patient-reported outcomes (PROs), minimal clinically important difference, and complications were reported during the final follow-up evaluation.

RESULTS

A total of 23 patients were included in the final analysis, with an average follow-up of 26.6 ± 3.4 months (range, 24-32 months). All patients diagnosed with symptomatic DDH exhibited labrum tears. MRI scans revealed paralabral cysts in 10 of 24 (41.6%) patients, with a significant correlation noted between the presence of cysts and preoperative lateral center-edge angle (ρ = -0.649; P = .001), anterior center-edge angle (ρ = -0.637; P = .001), Tönnis angle (ρ = 0.593; P = .002) and age (ρ = -0.444; P = .034). Postoperative MRI scans at 1 year showed resolution of all paralabral cysts, while labral tears were found to persist. At the end of the follow-up period, most patients improved considerably in PROs compared with preoperative values. The probabilities of achieving the minimal clinically important difference were 91.3% on the Hip Outcome Score-Activities of Daily Living, 78.2% on the Hip Outcome Score-Sports Subscale, 91.3% on the modified Harris Hip Score, 73.9% on the International Hip Outcome Tool 12-component form, and 69.6% on the visual analog scale pain scale.

CONCLUSIONS

All symptomatic patients with DDH had labral tears and a high prevalence of paralabral cysts, which were corrected with reduced acetabular coverage. After PAO surgery, patients experienced notable enhancements in PROs, with resolution of paralabral cysts but persistence of labral tears.

LEVELS OF EVIDENCE

Level Ⅳ, retrospective case series.

Is Prior Nonoperative or Operative Treatment of Dysplasia of the Hip Associated With Poorer Results of Periacetabular Osteotomy?

BACKGROUND

Understanding the implications of either nonoperative or operative treatment of developmental dysplasia of the hip (DDH) performed before periacetabular osteotomy (PAO) is critical to counseling patients and their families. There are limited studies, however, on PAO for the treatment of residual DDH after surgical intervention during childhood, and even less information about PAO after prior nonoperative treatment.

QUESTIONS/PURPOSES

We analyzed patients who had undergone PAO for DDH and asked: Did patients with prior childhood treatment (either operative or nonoperative) (1) improve less in modified Harris hip score (mHHS), 12-item International Hip Outcome Tool (iHOT-12) score, or WOMAC score; (2) demonstrate more severe preoperative deformities; and (3) receive less complete radiographic correction and have more frequent complications than did patients whose hips had not undergone prior treatment? We also asked: (4) Were there subgroup differences among patients with DDH treated nonoperatively versus operatively before PAO in these same functional and radiographic parameters?

METHODS

Between January 2011 and December 2020, a total of 90 PAOs were performed in 82 patients who had prior surgical or nonsurgical treatment. Of those, 3 patients (3 hips) with neuromuscular diseases were excluded, 4 patients (5 hips) were excluded for having received treatment after childhood, 7 hips that had undergone bilateral PAOs were excluded, and another 4 patients (4 hips) were lost to follow-up before the minimum study period of 2 years, leaving 71 patients (71 hips) for analysis (the previous treatment group). Among these, 32 patients had a history of previous surgery (the previous surgery group), and 39 patients had prior nonsurgical treatment (such as a Pavlik harness, closed reduction, spica casting) (the previous nonoperative group). During the same period, 1109 PAOs were performed in 956 patients who had no history of previous hip treatment. Following a 1:2 ratio, 142 patients (142 hips) were selected as the control group by matching for age (within 2 years difference), year of surgery (same year), and follow-up time (within 1-year difference). The patient characteristics for both the previous treatment group and the control group exhibited comparability, with mean ± SD follow-up durations of 49 ± 23 months and 48 ± 19 months, respectively. Within the previous 5 years, 3 patients (8%) in the previous nonoperative group, 4 patients (13%) in the previous surgery group, and 15 patients (11%) in the control group had not attended follow-up visits. We compared hip function and radiographic results between the two groups and performed a subgroup analysis between the previous surgery group and the previous nonoperative group. Hip function was assessed using the mHHS questionnaire, the WOMAC, and the iHOT-12 with attention to the minimum clinically important differences of these tools. The threshold values for clinically important improvement were 9.6 points, 13 points, and 16.1 points for the mHHS, iHOT-12, and WOMAC, respectively. Radiographic measurements included the lateral center-edge angle (LCEA), anterior center-edge angle (ACEA), Tönnis angle, acetabulum-head index, and acetabular wall index. We also evaluated Tönnis osteoarthritis grade and femoral head deformity. Occurrences of adverse radiographic events such as posterior column fracture, nonunion, stress fractures, insufficient coverage or overcoverage, acetabular protrusion, and progression of osteoarthritis were recorded.

RESULTS

We found no clinically important differences in magnitude of improvement between the previous treatment group and the control group in terms of mHHS (mean ± SD 10 ± 12 versus 12 ± 12; p = 0.36), iHOT-12 (25 ± 18 versus 26 ± 19; p = 0.51), or WOMAC score (12 ± 12 versus 15 ± 19; p = 0.17). Preoperative deformity in the previous treatment group was more severe than in the control group (mean ± SD LCEA -1° ± 9° versus 5° ± 8°; ACEA -8° ± 18° versus 1° ± 14°; Tönnis angle 31° ± 7° versus 27° ± 7°; acetabulum-head index 56% ± 13% versus 61% ± 8%; all p < 0.001). In the previous treatment group, a higher percentage of patients exhibited flattening or irregularity of the femoral head compared with the control group (52% versus 9%; p < 0.001), and there was also a higher proportion of patients with Tönnis grade 1 or above (51% versus 42%; p < 0.001). Although there were still differences in LCEA, ACEA, and Tönnis angle between the two groups at the last follow-up, the differences were small, and the mean values were within the normal range. The previous treatment group had a higher risk of intraoperative posterior column fracture (14% and 5%; p = 0.02), insufficient acetabular coverage (20% and 8%; p = 0.01), and progression of osteoarthritis (17% and 8%; p = 0.04) compared with the control group. Subgroup analysis revealed no clinically important differences in magnitude of improvement between the previous surgery group and the previous nonoperative group in terms of mHHS (10 ± 14 versus 10 ± 11; p = 0.91), iHOT-12 (22 ± 21 versus 27 ± 14; p = 0.26), or WOMAC score (12 ± 14 versus 12 ± 11; p = 0.94). Apart from a higher proportion of patients who presented with arthritis (72% versus 34%; p = 0.01) and a smaller anterior wall index (11% ± 11% versus 20% ± 12%; p = 0.01) in the previous surgery group, all other preoperative radiographic parameters were consistent between the two groups. Additionally, the previous surgery group had a higher frequency of arthritis progression (28% versus 8%; p = 0.02), while the frequencies of other complications were similar between the two groups. Specifically, the frequencies of pubic ramus nonunion (22% versus 21%; p = 0.89), intraoperative posterior column fracture (19% versus 10%; p = 0.50), and insufficient acetabular coverage (25% versus 15%; p = 0.31) were high in both groups.

CONCLUSION

We found no clinically important difference in the magnitude of improvement between patients who had childhood treatment and those who did not, but patients who had prior childhood treatment were more likely to experience serious complications, and radiographic correction in those patients was less complete. As in the case of patients who have had prior operative treatments, it is crucial not to overlook the unexpectedly severe deformity of residual DDH after previous nonoperative treatment and complications following PAO. Surgeons and patients alike should be aware of the potential for worse radiographic outcomes or an increased risk of complications when prior operative or nonoperative treatment has preceded PAO. Future studies might investigate optimal management strategies for this specific group of patients to improve outcomes and reduce complications.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Three-dimensional acetabular reorientation during periacetabular osteotomy: an intraoperative navigation method using an external fixator for periacetabular osteotomy

INTRODUCTION

Bernese periacetabular osteotomy (PAO) is an effective procedure for treating acetabular dysplasia. However, limited visual control of the acetabular position during surgery may result in under- or overcorrection or changes in acetabular version resulting in residual dysplasia or femoroacetabular impingement. Thus, we wanted to develop a simple and straightforward navigation method that provides information about acetabular correction in all three planes during surgery.

METHOD

Intraoperatively, acetabular coordinates are shown in coronal, sagittal, and transverse plane by two perpendicular tubes of an external fixator mounted onto a third tube that is fixed to the mobilized acetabular fragment with two Schanz screws. The application and fixation of the external fixator on the pelvis are demonstrated in this article. We used this analog navigation method on 27 PAOs, where we mainly performed a lateral rotational correction. The pre- and postoperative radiographs of these 27 hips were analyzed regarding the radiological hip parameters, taking into account the pelvic tilt.

RESULTS

The mean preoperative lateral center edge angle (LCEA) of the 27 PAOs improved from 16° (+-6) to a mean of 34° (+-6°) and the mean acetabular index (AI) was corrected from 15° (+-4) to 2° (+-4). This implements highly physiologic postoperative values for lateral coverage in this population. In this case series, no postoperative acetabular retroversion was measured in any of the 27 PAOs.

CONCLUSION

Three-dimensional control of the acetabular orientation during periacetabular osteotomy is important to avoid over- and undercorrection. Using a fixateur externe as an analog navigation method this three-dimensional control can be implemented intraoperatively for PAOs.

Risk Factors for Failure of Hip Arthroscopy in Patients With Borderline Dysplasia Include a Tönnis Angle ≥15°, Age ≥40 to 42 Years, Female Sex, Anterior Wall Index <0.35, Labral Debridement, and Preexisting Hip Osteoarthritis: A Systematic Review

PURPOSE

To systematically review the literature to determine potential risk factors for failure of hip arthroscopy (HA) in patients with borderline hip dysplasia (BHD).

METHODS

A systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines by searching PubMed, the Cochrane Library, and Embase to identify English-language clinical studies reporting on patients with BHD undergoing HA from 2003 to 2023. The search terms used were (borderline OR mild) AND hip AND (arthroscopy OR dysplasia) AND failure. The primary outcomes assessed were risk factors reported by each study for failure of a HA-only approach in patients with BHD.

RESULTS

Fourteen studies (8 Level III, 6 Level IV) met inclusion criteria, totaling 749 hips. Patient age ranged from 29.8 to 39.2 years, with a mean follow-up ranging from 24.0 to 144.0 months. The overall percentage of female patients ranged from 11.8% to 100.0%. Overall, the clinical failure rate ranged from 0 to 53.3%, and the reoperation rate ranged from 0 to 44.0%. The predominant predictors of poor outcomes after HA alone included Tönnis angle ≥15°, age ≥40 to 42 years at surgery, and female sex. Other risk factors for failure were preoperative clinical arthritis, grade 3 or 4 articular cartilage changes to the femoral head or acetabulum, an anterior wall index <0.35, and labral debridement. Revision procedures performed included revision HA (n = 88, 0-28.0%), total hip arthroplasty (n = 55, 0%-23.7%), and endoscopic shelf acetabuloplasty (n = 5, 0%-11.0%). One study included an additional 9 patients converting to either periacetabular osteotomy or total hip arthroplasty without distinguishing between the two.

CONCLUSIONS

For patients with BHD, Tönnis angle ≥15°, age ≥40 to 42 years at surgery, female sex, anterior wall index <0.35, labral debridement, and pre-existing hip osteoarthritis are common risk factors for treatment failure following isolated HA.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III-IV studies.

Use of oblique view in periacetabular osteotomy and delayed postoperative weight bearing reduce delayed union in the ischium after one year

This study aimed to determine the efficacy of using both the postero-anterior and oblique image intensifier views intra-operatively and late start of post-operative partial weight-bearing (PWB) in reducing the incidence of delayed union in the ischium at one year after curved periacetabular osteotomy. We evaluated computed tomography images to clarify the incidence of delayed union at the osteotomy sites at one year post-operatively for 117 hips in 104 patients. Fifty-eight hips in 54 patients with use of both the postero-anterior and oblique image intensifier views intra-operatively and late start of post-operative PWB were assigned to the oblique view and late PWB group (OL group) and 59 hips in 50 patients with use of only the postero-anterior image intensifier view intra-operatively and early start of post-operative PWB were assigned to the control group (C group). In univariate analyses, the incidence of delayed union in the ischium at one year post-operatively was significantly lower in the OL group (3.5%) than in the C group (22%). Use of both the postero-anterior and oblique image intensifier views during curved periacetabular osteotomy and late start of PWB were effective for reducing delayed union of the ischium at one year post-operatively.

Development of an aid to detect adults acetabular hip dysplasia (the ALPHA alert): A mixed methods study

OBJECTIVES

To identify the signs and symptoms that people living with acetabular hip dysplasia (AHD) describe and to provide an aid for translating the findings into practice.

METHODS

A three-phased mixed methods study. Phase 1 employed an open-question online survey that enabled people with AHD (aged ≥16 years) to describe features associated with their condition. Responses were thematically analysed. A Phase 2 survey used these themes to establish how common those features were. Phase 3 created a mnemonic that prompts clinicians to suspect AHD.

RESULTS

Ninety-eight respondents completed Phase 1 and sixty-two completed Phase 2. From the responses, five themes were identified: Demographic and Diagnostic Profile; Characteristics of Posture and Gait; Pain; Childhood Hip and Family History; and Hip Joint Characteristics. Within these themes, 19 common signs and symptoms were reported, represented by the ALPHA mnemonic. ALPHA describes a young age at onset of problems (Age), a limp (Limp), progressing pain (Pain), a history of childhood and family hip anomalies (History) as well as hip joint hypermobility and instability (Articulation).

CONCLUSION

The findings extend current understanding of AHD indicators. ALPHA alerts clinicians to suspect a diagnosis of AHD. ALPHA may facilitate timelier referral of patients for diagnostic X-Ray and appropriate treatment. Future studies should evaluate its clinical utility.

The critical importance of recognition, evaluation, and management of mental health on outcomes following hip arthroscopy - A synthetic narrative review: Current concepts

Mental health and wellness influence patients with hip pain and dysfunction secondary to Femoroacetabular Impingement Syndrome, acetabular dysplasia, and labral injury. Disorders of mental wellness may impact hip preservation surgery patients both before and after surgery. Major depression and generalized anxiety are the two most common diagnoses that affect hip preservation surgery patients. There are dozens of unique questionnaires that can subjectively and objectively characterize the mental health of patients with hip pain. Pain threshold and pain tolerance are two issues that must be recognized to optimally predict treatment outcome in an informed consent shared decision-making discussion. Patient expectations may also significantly influence preoperative symptoms and postoperative outcome. Pain threshold, pain tolerance, and patient expectations are entities traditionally viewed as qualitative and unmeasurable. However, many valid and reliable methods exist to quantitatively assess these patient-specific variables. Recent original research and synthetic review publications have consistently concluded similar findings: patients with disorders of mental wellness generally have lower preoperative patient-reported outcome scores, do improve following surgery, albeit to a lesser magnitude than non-mental disorder patients, and ultimately have lower postoperative scores at their final follow. As with most orthopaedic surgery literature, the investigation of mental health and hip preservation is primarily via retrospective level four evidence with small numbers of patients from a single centre and single surgeon at short-term follow-up. Although hip preservation surgeons are orthopaedic surgeons by training and practice, they must be able to recognize mental wellness disorders and either treat or refer when suspected or identified.

Three-dimensional assessment of subchondral arc and hip joint coverage angles in the asymptomatic young adult hip

The primary objective of this study was to develop a custom algorithm to assess three-dimensional (3D) acetabular coverage of the femoral head based on surface models generated from computed tomography (CT) imaging. The secondary objective was to apply this algorithm to asymptomatic young adult hip joints to assess the regional 3D acetabular coverage variability and understand how these novel 3D metrics relate to traditional two-dimensional (2D) radiographic measurements of coverage. The algorithm developed automatically identifies the lateral- and medial-most edges of the acetabular lunate at one-degree intervals around the acetabular rim based on local radius of curvature. The acetabular edges and the center of a best-fit sphere to the femoral head are then used to compute the mean 3D subchondral arc angles and hip joint coverage angles in five acetabular octants. This algorithm was applied to hip models generated from pelvis/hip CT imaging or abdomen/pelvis CT angiograms of 50 patients between 17 and 25 years of age who had no history of congenital or developmental hip pathology, neuromuscular conditions, or bilateral pelvic and/or femoral fractures. Corresponding 2D acetabular coverage measures of lateral center edge angle (LCEA) and acetabular arc angle (AAA) were assessed on the patients' clinical or digitally reconstructed radiographs. The 3D subchondral arc angle in the superior region (58.0 [54.6-64.8] degrees) was significantly higher (p < 0.001) than all other acetabular subregions. The 3D hip joint coverage angle in the superior region (26.2 [20.7-28.5] degrees) was also significantly higher (p < 0.001) than all other acetabular subregions. 3D superior hip joint coverage angle demonstrated the strongest correlation with 2D LCEA (r = 0.649, p < 0.001), while 3D superior-anterior subchondral arc angle demonstrated the strongest correlation with 2D AAA (r = 0.718, p < 0.001). The 3D coverage metrics in the remaining acetabular regions did not strongly correlate with typical 2D radiographic measures. The discrepancy between standard 2D measures of radiographic acetabular coverage and actual 3D coverage identified on advanced imaging indicates potential discord between anatomic coverage and the standard clinical measures of coverage on 2D imaging. As 2D measurement of acetabular coverage is increasingly used to guide surgical decision-making to address acetabular deformities, this work would suggest that 3D measures of acetabular coverage may be important to help discriminate local coverage deficiencies, avoid inconsistencies resulting from differences in radiographic measurement techniques, and provide a better understanding of acetabular coverage in the hip joint, potentially altering surgical planning and guiding surgical technique.

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.

Factors associated with joint survival after transposition osteotomy of the acetabulum in patients with Tönnis grade 2 osteoarthritis secondary to hip dysplasia

Aims

The aim of this study was to determine the clinical outcomes and factors contributing to failure of transposition osteotomy of the acetabulum (TOA), a type of spherical periacetabular osteotomy, for advanced osteoarthritis secondary to hip dysplasia.

Methods

We reviewed patients with Tönnis grade 2 osteoarthritis secondary to hip dysplasia who underwent TOA between November 1998 and December 2019. Patient demographic details, osteotomy-related complications, and the modified Harris Hip Score (mHHS) were obtained via medical notes review. Radiological indicators of hip dysplasia were assessed using preoperative and postoperative radiographs. The cumulative probability of TOA failure (progression to Tönnis grade 3 or conversion to total hip arthroplasty) was estimated using the Kaplan-Meier product-limited method. A multivariate Cox proportional hazards model was used to identify predictors of failure.

Results

This study included 127 patients (137 hips). Median follow-up period was ten years (IQR 6 to 15). The median mHHS improved from 59 (IQR 52 to 70) preoperatively to 90 (IQR 73 to 96) at the latest follow-up (p < 0.001). The survival rate was 90% (95% CI 82 to 95) at ten years, decreasing to 21% (95% CI 7 to 48) at 20 years. Fair joint congruity on preoperative hip abduction radiographs and a decreased postoperative anterior wall index (AWI) were identified as independent risk factors for failure. The survival rate for the 42 hips with good preoperative joint congruity and a postoperative AWI ≥ 0.30 was 100% at ten years, and remained at 83% (95% CI 38 to 98) at 20 years.

Conclusion

Although the overall clinical outcomes of TOA in patients with advanced osteoarthritis are suboptimal, favourable results can be achieved in selected cases with good preoperative joint congruity and adequate postoperative anterior acetabular coverage.

Trends, demographics and reoperation rates of periacetabular osteotomy: an analysis from the PearlDiver database

This study aims to examine the trends and demographics of periacetabular osteotomy (PAO) in the United States from 2016 to 2020 using a large healthcare database analysis. The PearlDiver database was queried for patients who underwent a PAO procedure starting with current procedural terminology (CPT) codes 27299, S2115 and 27146. Subsequently, the population was filtered for patients being ages 12-50, having an inpatient charge-type and those having a length of stay of at least 1 day. Patients with total hip arthroplasty were filtered out, and the resulting population was filtered by ICD-10 diagnosis codes. The providers of each patient were also examined to ensure their history of treating hip dysplasia. Student t and multiple regression analysis tests were used for statistical comparisons and trends analysis (P < 0.05 reported as significant). A total of 535 consecutive patients were analyzed over the study period. There was a higher incidence of PAO in females compared with males (P < 0.001) and a higher incidence of PAO in patients aged 15-19 years compared with older age groups (P = 0.017). Within the first year after the index PAO, 171 of the 535 patients, almost one-third (32%), received a reoperation. Of the 171 reoperations, 115 were deep removal of implant, 55 were a hip arthroscopy and 1 patient had a bone excision for heterotopic ossification. Similar studies should be carried out using other large health databases to confirm the external validity of these trends and rates across the United States.

Quantifying radiation exposure in the radiological investigation of non-arthritic hip pain

Radiological investigations are essential for evaluating underlying structural abnormalities in patients presenting with non-arthritic hip pain. The aim of this study is to quantify the radiation exposure associated with common radiological investigations performed in assessing patients presenting with non-arthritic hip pain. A retrospective review of our institutional imaging database was performed. Data were obtained for antero-posterior, cross-table lateral, frog lateral radiographs and low-dose CT hip protocol. The radiation dose of each imaging technique was measured in terms of dose-area product with units of mGy cm2, and the effective doses (ED, mSv) calculated. The effective radiation dose for each individual hip radiograph performed was in the range of 0.03-0.83 mSv [mean dose-area product 126.7-156.2 mGy cm2]. The mean ED associated with the low-dose CT hip protocol (including assessment of femoral anteversion and tibial torsion) was 3.04 mSv (416.8 mGy cm2). The radiation dose associated with the use of CT imaging was significantly greater than plain radiographs (P < 0.005). Investigation of non-arthritic hip pain can lead to significant ionizing radiation exposure for patients. In our institution, the routine protocol is to obtain an antero-posterior pelvic radiograph and then a specific hip sequence Magnetic Resonance Imaging (MRI) scan which includes the assessment of femoral anteversion. This provides the necessary information in the majority of cases, with CT scanning reserved for more complex cases where we feel there is a specific indication. We would encourage the hip preservation community to carefully consider and review the use of ionizing radiation investigations.

Primary Hip Arthroscopy in Patients With Acetabular Dysplasia: A Systematic Review of Published Clinical Outcomes at Minimum 5-Year Follow-up

BACKGROUND

Hip arthroscopy in patients with borderline hip dysplasia has satisfactory outcomes at short-term follow-up; however, the data on midterm outcomes are inconsistent, and failure rates are high in some studies, limiting understanding of the role and utility of hip arthroscopy in this patient cohort.

PURPOSE

To provide an up-to-date, evidence-based review of the clinical outcomes of primary hip arthroscopy in patients with frank or borderline hip dysplasia at ≥5-year follow-up and report the failure rate and progression to total hip arthroplasty in this cohort.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A comprehensive literature search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were included if they evaluated outcomes of primary hip arthroscopy in patients with lateral center-edge angle (LCEA) <25° at ≥5-year follow-up. Risk of bias assessment was performed using the methodological index for non-randomized studies scoring system. Level of evidence was determined using criteria from the Oxford Centre for Evidence-Based Medicine.

RESULTS

Nine studies were included in this review. Patients with LCEA <25° demonstrated satisfactory clinical outcomes, high patient satisfaction, and significant postoperative improvements in patient-reported outcomes (PROs) at follow-up ranging from a ≥5 to 10 years. Studies comparing patients with dysplasia to those without did not demonstrate significant differences in preoperative, postoperative, or delta PROs or in failure, reoperation, or revision rates. There was no overall significant correlation between outcomes and LCEA stratification.

CONCLUSION

Hip arthroscopy in carefully selected patients with LCEA <25° can be successful at mid- to long-term follow-up and may provide clinical outcomes and failure rates comparable with patients with normal LCEA, understanding that this is a singular, 2-dimensional radiographic measure that does not differentiate instability from impingement or combinations thereof, warranting future studies delineating these differences. These findings suggest that hip dysplasia may not be an absolute contraindication for isolated hip arthroscopy and may serve as a viable intervention with consideration of staged future periacetabular osteotomy (PAO). Importantly, this review does not suggest that hip arthroscopy alters the natural history of dysplasia; therefore, patients with dysplasia should be counseled on the potential utility of PAO by appropriate hip preservation specialists.

The role of different acetabular morphologies on patient-reported outcomes following periacetabular osteotomy in borderline hip dysplasia

INTRODUCTION

The treatment option for borderline hip dysplasia (BHD) includes hip arthroscopy and periacetabular osteotomy (PAO). To the present day the controversial discussion remains, which intervention to prefer. Literature reports supporting an educated choice are scare, based on small patient cohorts and do not address the variability of acetabular morphology. Consequently, we intended to report PAO outcomes, from patients diagnosed with BHD, dependent on acetabular morphology, in a large patient cohort and aimed to define risk factors for poor clinical results and patient satisfaction.

MATERIALS AND METHODS

A prospective monocentre study was conducted. Patients enrolled underwent PAO for symptomatic BHD (LCEA, 18°-25°). A total of 107 hips were included with 94 complete data sets were available for evaluation with a minimum follow-up of 1 year and a mean follow-up of 2.3 years. The mean age was 31 ± 8.2 years, and 81.3% were female. As the primary outcome measure, we utilized the modified Harris hip score (mHHS) with minimal clinically important change (MCID) of eight to define clinical failure. Results were compared after a comprehensive radiographic assessment distinguishing between lateral deficient vs. anterior/posterolateral deficient acetabular and stable vs. unstable hip joints.

RESULTS

Overall, clinical success was achieved in 91.5% of patients and the mHHS improved significantly (52 vs. 84.7, p < 0.001). Eight hips failed to achieve the MCID and four had radiographic signs of overcorrection. Comparing variable joint morphologies, the rate of clinical success was higher in patients with an anterior/posterolateral deficient acetabular covarage compared to lateral deficient acetabular (95.2% vs. 90.4%). tThe highest rate of clinical failure was recorded in unstable hip joints (85.7% vs. 92.5% in stable hips).

CONCLUSIONS

This study demonstrates that PAO is an effective means to treat symptomatic BHD with variable acetabular morphologies, achieving a clinical success in 91.5% of all patients. To maintain a high level of safety and patient satisfaction technical accuracy appears crucial.

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

INTRODUCTION

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

A pilot screening project for the detection of hip dysplasia in young patients

Hip dysplasia in young adults is underdiagnosed and can cause pain and discomfort. Progression to osteoarthritis (OA) is common, necessitating total hip arthroplasty at an early age. When discovered early, symptomatic patients can be offered physiotherapy and/or hip-preserving surgery to alleviate pain and decrease the risk of early OA. A pilot project to screen radiograms for hip dysplasia was started across the Swedish region of Örebro Län in January 2019, comparing the incidence of dysplasia before and after initiation of the screening program. All elective conventional radiograms of the hip (age 12-44 years), requested by primary care physicians, were analyzed by consultant radiologists according to a pre-established algorithm to identify hip abnormalities. If the hip radiograms showed dysplastic changes, or other pathological signs, the radiologist advised referral to a specialized Youth Hip Clinic for further work-up and treatment. A total of 1056 radiograms were requested by clinicians during the study periods (601 and 455 during 2018 and 2020, respectively). A total of 457 trauma-related cases were excluded, resulting in 599 available for analysis (348 and 251 during 2018 and 2020, respectively). During 2018, 17 patients (4.9%) received the radiologic diagnosis of dysplasia, compared with 44 patients (17.5%) during 2020 (P < 0. 001). A three-fold increase of patients diagnosed with hip dysplasia was detected as a result of the implementation of the screening program. The advantage of screening is early referral to an orthopedic department for evaluation and consideration for physiotherapy and/or surgical intervention.

The Use of Combined Hip Arthroscopy and Periacetabular Osteotomy for Hip Dysplasia Is Increasing and Has Low Complication Rates

Purpose

To analyze the annual use of hip arthroscopy (HA) and Bernese periacetabular osteotomy (PAO) for the treatment of hip dysplasia (HD), as well as postoperative outcomes, including ipsilateral reoperations.

Methods

International Classification of Diseases, Ninth and Tenth Revision, codes were used to query the PearlDiver Mariner database from January 2010 through January 2022 to identify patients aged 10 to 59 years who had a presenting diagnosis of HD and subsequently underwent (1) HA; (2) PAO; or (3) combined HA and PAO (HA-PAO, defined as PAO on the same day or within 28 days after HA). We analyzed annual rates for each treatment, as well as rates of postoperative emergency visits, readmissions, and 5-year ipsilateral secondary operations (determined via Kaplan-Meier analysis).

Results

There were 32,068 patients who underwent surgical treatment of HD. For HA, PAO, and HA-PAO, there were 29,700, 2,083, and 285 patients, respectively. All operations had the greatest percent-increase from 2015 to 2016. HA and HA-PAO peaked in 2021, whereas PAO peaked in 2019. For HA, PAO, and HA-PAO, most cases were performed in female patients and patients aged 30 to 49 years, 10 to 19 years, and 10 to 29 years, respectively. The 5-year incidence of ipsilateral secondary operations, which include revision HA, PAO, or conversion to total hip arthroplasty, was 9.2% (95% confidence interval 8.6%-9.8%) in the HA group and 6.5% (95% confidence interval 4.1%-8.8%) in the PAO group. Combining HA with PAO resulted in so few secondary operations that Kaplan-Meier analysis was infeasible. The PAO cohort had the greatest 30-day emergency visit and 90-day readmission rates, with infection as the most common cause for readmission.

Conclusions

HA is more frequently performed than PAO for hip dysplasia. HA-PAO is increasing at the greatest rate, demonstrating fewer complications and reoperations.

Level of Evidence

Level III, retrospective comparative trial.

A 30-year follow-up study of rotational acetabular osteotomy for pre- and early-stage osteoarthritis secondary to dysplasia of the hip

Aims

The objective of this study was to present the outcomes of rotational acetabular osteotomy (RAO) over a 30-year period for osteoarthritis (OA) secondary to dysplasia of the hip in pre- or early-stage OA.

Methods

Between September 1987 and December 1994, we provided treatment to 47 patients (55 hips) with RAO for the management of pre- or early-stage OA due to developmental hip dysplasia. Of those, eight patients (11 hips) with pre-OA (follow-up rate 79%) and 27 patients (32 hips) with early-stage OA (follow-up rate 78%), totalling 35 patients (43 hips) (follow-up rate 78%), were available at a minimum of 28 years after surgery.

Results

In the pre-OA group, the mean Merle d'Aubigné score improved significantly from 14.5 points (SD 0.7) preoperatively to 17.4 points at final follow-up (SD 1.2; p = 0.004) and in the early-stage group, the mean score did not improve significantly from 14.0 (SD 0.3) to 14.6 (SD 2.4; p = 0.280). Radiologically, the centre-edge angle, acetabular roof angle, and head lateralization index were significantly improved postoperatively in both groups. Radiological progression of OA was observed in two patients (two hips) in the pre-OA group and 17 patients (18 hips) in the early-stage group. Kaplan-Meier survival analysis, with radiological progression of OA as the primary outcome, projected a 30-year survival rate of 81.8% (95% confidence interval (CI) 0.59 to 1.00) for the pre-OA group and 42.2% (95% CI 0.244 to 0.600) for the early-stage group. In all cases, the overall survival rate stood at 51.5% (95% CI 0.365 to 0.674) over a 30-year period, and when the endpoint was conversion to total hip arthroplasty, the survival rate was 74.0% (95% CI 0.608 to 0.873).

Conclusion

For younger patients with pre-OA, joint preservation of over 30 years can be expected after RAO.

Retroverting Periacetabular Osteotomy for Symptomatic Acetabular Anteversion

BACKGROUND

Acetabular dysplasia has traditionally been defined using the lateral center edge angle and treated with periacetabular osteotomy (PAO). However, the recently described Ottawa classification further quantifies dysplasia in 3-dimensional terms, categorizing Ottawa A as dysplasia due to isolated, excessive acetabular anteversion or anterior acetabular under-coverage. We sought to determine if patients who have Ottawa A dysplasia can expect similar outcomes when undergoing a PAO compared to a traditional dysplasia cohort.

METHODS

Patients who had undergone PAO with Ottawa A hip dysplasia were selected and compared to a control group of patients who had lateral acetabular undercoverage. The modified Harris Hip Score and International Hip Outcome Tool-33 were collected preoperatively and at various follow-up points for a final follow-up average of 2.3 years (range, 0.9 to 6.2).

RESULTS

The 17 patients (21 hips) who had Ottawa A dysplasia were compared to a control cohort of 69 patients (88 hips). Both groups saw significant improvements in modified Harris Hip Score and International Hip Outcome Tool-33 at final follow-up, P < .001. There were no differences between groups in any of the outcome measures or rates of achieving minimal clinically important difference (MCID) or substantial clinical benefit. Rates of MCID ranged from 82.4 to 100%, and rates of achieving substantial clinical benefit ranged from 47.1 to 52.9%.

CONCLUSIONS

In patients undergoing a PAO for Ottawa A hip dysplasia, a significant improvement in patient-reported outcomes can be expected with high rates of MCID achievement. This is not significantly different for patients undergoing PAO for more traditional dysplasia parameters.

Providing a computationally derived, mechanically optimised target correction during preoperative planning can improve joint contact mechanics of hip dysplasia treated with periacetabular osteotomy

AIM

Preoperative identification of acetabular corrections that optimally improve joint stability and reduce elevated contact stresses could further reduce osteoarthritis progression in patients with hip dysplasia who are treated with periacetabular osteotomy (PAO). The purpose of this study was to investigate how providing patient-specific, mechanically optimal acetabular reorientations to the surgeon during preoperative planning affected the surgically achieved correction.

METHODS

Preoperative CT scans were used to create patient-specific hip models for 6 patients scheduled for PAO. A simulated acetabular fragment was extracted from the preoperative pelvis model and computationally rotated to simulate candidate acetabular reorientations. For each candidate, discrete element analysis was used to compute contact stresses during walking, which were summed over the gait cycle and scaled by patient age to obtain chronic contact stress-time exposure. The ideal patient-specific reorientation was identified using a cost function that balances minimising chronic stress exposures and achieving surgically acceptable acetabular coverage angles. The optimal reorientation angles and associated contact mechanics were provided to the surgeon preoperatively. After PAO was performed, a model of the surgically achieved correction was created from a postoperative CT scan. Radiographic coverage and contact mechanics were compared between preoperative, optimal, and surgically achieved orientations.

RESULTS

While surgically achieved reorientations were not significantly different from optimal reorientations in radiographically measured lateral (p = 0.094) or anterior (p = 0.063) coverage, surgically achieved reorientations had significantly (p = 0.031) reduced total contact area compared to optimal reorientations. The difference in lateral coverage and peak chronic exposure between surgically achieved and optimal reorientations decreased with increasing surgeon experience using the models (R² = 0.758, R2 = 0.630, respectively).

CONCLUSIONS

Providing hip surgeons with a patient-specific, computationally optimal reorientation during preoperative planning may improve contact mechanics after PAO, which may help reduce osteoarthritis progression in patients with hip dysplasia.

Long-term results of a modified Spitzy shelf operation for hip dysplasia: 79 adults with a mean follow-up of 33 years

BACKGROUND

There is no consensus regarding the treatment of symptomatic hip dysplasia in adolescents and adults. Most previous studies have insufficient follow-up time.

AIM

The aim of this study was to assess the long-term outcome of a modified Spitzy shelf procedure.

METHODS

We reviewed 79 adults with 94 acetabular shelf operations between 1976 and 2000. Mean age at surgery was 33.7 years (range 13-54). Indication for surgery was acetabular dysplasia with or without hip pain. Outcome was evaluated using hip pain pre- and postoperatively and Kaplan-Meier survival analysis with conversion to total hip replacement (THR) as the endpoint.

RESULTS

Hip pain was reported in 84% of the hips preoperatively and in 21% one year postoperatively. 63 hips (65%) had undergone THR at a mean patient age of 54.3 years (range 29-76). The mean survival time from Spitzy operation to THR was 17.2 years (range 1-39). Survival was 86% at 10-year follow-up, 56% at 20-year follow-up, and 36% at 30-year follow-up. Predictors of THR were age at surgery ≥ 30 years and preoperative osteoarthritis (OA). The rate of complications was 12%, but most were mild to moderate.

CONCLUSIONS

The modified Spitzy shelf operation had a good effect on hip pain. The long-term survival with conversion to THR as the endpoint in hips without preoperative OA was similar to that reported after periacetabular osteotomy. This indicates that the shelf procedure may be a suitable option in adolescents and young adults with milder degrees of hip dysplasia without OA.

A New Arthroscopic Classification for Chondrolabral Disease in Patients Undergoing Surgery for Developmental Dysplasia of the Hip

BACKGROUND

Current classification systems for intra-articular pathology intraoperatively have been described for patients with femoroacetabular impingement rather than dysplasia.

PURPOSE

To (1) describe intra-articular findings in dysplastic hips undergoing combined hip arthroscopy and periacetabular osteotomy (PAO); (2) propose a new chondrolabral classification system for dysplastic hips based on these findings; and (3) correlate patient-reported outcome measures (PROM) with the newly proposed classification.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 46 hips underwent combined hip arthroscopy and PAO at our institution between September 2013 and December 2014, irrespective of symptoms or radiographic findings. PROMs were evaluated preoperatively and at 2 years postoperatively. At the time of hip arthroscopy, the chondrolabral junction was classified as normal without tear (1 hip, type 1); hypertrophic labrum without chondrolabral disruption (19 hips, type 2); chondrolabral disruption on the articular side, not extending into the capsular side (16 hips, type 3A); chondrolabral disruption extending through the capsular side (3 hips, type 3B); and exposed acetabular subchondral bone (7 hips, type 4).

RESULTS

There was a significant difference in postoperative modified Harris Hip Score (mHHS) (P = .020), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scores (P = .037), and WOMAC total scores (P = .049) between chondrolabral junction types. Post hoc analyses demonstrated significant differences between type 2 (84.9 ± 12.9) and type 3A (67.8 ± 20.7; P = .198), and between type 2 and type 4 (59.3 ± 24.3; P = .011) in postoperative mHHS scores; and between type 2 (83.9 ± 12.9) and type 3A (68.9 ± 23.7; P = .045) in postoperative WOMAC total scores. In multivariate analysis, chondrolabral type 3 or type 4, age >35 years, and previous surgery were significantly correlated with worse mHHS scores at 2 years.

CONCLUSION

This new chondrolabral classification is proposed to describe intra-articular pathology seen during combined hip arthroscopy and PAO, specifically in dysplastic hips. More advanced chondrolabral disease was associated with worse PROMs at 2 years.

Periacetabular osteotomy for symptomatic hip dysplasia in middle aged patients: does age alone matter?

BACKGROUND

Conflicting evidence exists regarding outcomes in middle-aged patients undergoing periacetabular osteotomy (PAO) for symptomatic developmental dysplasia of the hip (DDH).

AIMS

To compare patient reported outcomes (PROMs) of middle-aged PAO patients with younger patient groups.

METHODS

Retrospective analysis of prospectively collected data of PAO patients between 01/2015 and 06/2017 at a single orthopedic university center with a primary diagnosis of symptomatic DDH. The cohort was divided into four age groups and compared: < 20, 20-30, 30-40 and > 40 years. Joint function was assessed using iHOT-12, mHHS and SHV. Activity level was assessed using UCLA Activity score. Patient satisfaction and pain were assessed on the numerical rating scale 0-10. Conversion rates to THA were assessed.

RESULTS

Out of 202 PAOs, 120 cases with complete data were included. Mean follow-up was 63 months (range 47-81 months). Eighteen patients were < 20 years old, 54 were 20-30 years, 37 were 30-40 years, 11 patients were older than 40. No significant differences were observed for preoperative or postoperative iHOT-12 (p = 0.898; p = 0.087), mHHS (p = 0.878; p = 0.103), SHV (p = 0.602; p = 0.352) or UCLA (p = 0.539; p = 0.978) between groups. Improvement deltas were also not significantly different for all PROMs. Postoperative patient satisfaction was similar between groups (p = 0.783).

CONCLUSION

Patients with symptomatic DDH may benefit from PAO even at middle age with similar outcomes and pre- to postoperative improvements as younger age groups. Indication should be based on biological age and preoperative joint condition rather than age.

Which Acetabular Measurements Most Accurately Differentiate Between Patients and Controls? A Comparative Study

BACKGROUND

Acetabular morphology is an important determinant of hip biomechanics. To identify features of acetabular morphology that may be associated with the development of hip symptoms while accounting for spinopelvic characteristics, one needs to determine acetabular characteristics in a group of individuals older than 45 years without symptoms or signs of osteoarthritis. Previous studies have used patients with unknown physical status to define morphological thresholds to guide management.

QUESTIONS/PURPOSES

(1) To determine acetabular morphological characteristics in males and females between 45 and 60 years old with a high Oxford hip score (OHS) and no signs of osteoarthritis; (2) to compare these characteristics with those of symptomatic hip patients treated with hip arthroscopy or periacetabular osteotomy (PAO) for various kinds of hip pathology (dysplasia, retroversion, and cam femoroacetabular impingement); and (3) to assess which radiographic or CT parameters most accurately differentiate between patients who had symptomatic hips and those who did not, and thus, define thresholds that can guide management.

METHODS

Between January 2018 and December 2018, 1358 patients underwent an abdominopelvic CT scan in our institution for nonorthopaedic conditions. Of those, we considered 5% (73) of patients as potentially eligible as controls based on the absence of major hip osteoarthritis, trauma, or deformity. Patients were excluded if their OHS was 43 or less (2% [ 28 ]), if they had a PROMIS less than 50 (1% [ 18 ]), or their Tönnis score was higher than 1 (0.4% [ 6 ]). Another eight patients were excluded because of insufficient datasets. After randomly selecting one side for each control, 40 hips were left for analysis (age 55 ± 5 years; 48% [19 of 40] were in females). In this comparative study, this asymptomatic group was compared with a group of patients treated with hip arthroscopy or PAO. Between January 2013 and December 2020, 221 hips underwent hip preservation surgery. Of those, eight were excluded because of previous pelvic surgery, and 102 because of insufficient CT scans. One side was randomly selected in patients who underwent bilateral procedure, leaving 48% (107 of 221) of hips for analysis (age 31 ± 8 years; 54% [58 of 107] were in females). Detailed radiographic and CT assessments (including segmentation) were performed to determine acetabular (depth, cartilage coverage, subtended angles, anteversion, and inclination) and spinopelvic (pelvic tilt and incidence) parameters. Receiver operating characteristics (ROC) analysis was used to assess diagnostic accuracy and determine which morphological parameters (and their threshold) differentiate most accurately between symptomatic patients and asymptomatic controls.

RESULTS

Acetabular morphology in asymptomatic hips was characterized by a mean depth of 22 ± 2 mm, with an articular cartilage surface of 2619 ± 415 mm 2 , covering 70% ± 6% of the articular surface, a mean acetabular inclination of 48° ± 6°, and a minimal difference between anatomical (24° ± 7°) and functional (22° ± 6°) anteversion. Patients with symptomatic hips generally had less acetabular depth (20 ± 4 mm versus 22 ± 2 mm, mean difference 3 mm [95% CI 1 to 4]; p < 0.001). Hips with dysplasia (67% ± 5% versus 70% ± 6%, mean difference 6% [95% CI 0% to 12%]; p = 0.03) or retroversion (67% ± 5% versus 70% ± 6%, mean difference 6% [95% CI 1% to 12%]; p = 0.04) had a slightly lower relative cartilage area compared with asymptomatic hips. There was no difference in acetabular inclination (48° ± 6° versus 47° ± 7°, mean difference 0.5° [95% CI -2° to 3°]; p = 0.35), but asymptomatic hips had higher anatomic anteversion (24° ± 7° versus 19° ± 8°, mean difference 6° [95% CI 3° to 9°]; p < 0.001) and functional anteversion (22° ± 6° versus 13°± 9°, mean difference 9° [95% CI 6° to 12°]; p < 0.001). Subtended angles were higher in asymptomatic at 105° (124° ± 7° versus 114° ± 12°, mean difference 11° [95% CI 3° to 17°]; p < 0.001), 135° (122° ± 9° versus 111° ± 12°, mean difference 10° [95% CI 2° to 15°]; p < 0.001), and 165° (112° ± 9° versus 102° ± 11°, mean difference 10° [95% CI 2° to 14°]; p < 0.001) around the acetabular clockface. Symptomatic hips had a lower pelvic tilt (8° ± 8° versus 11° ± 5°, mean difference 3° [95% CI 1° to 5°]; p = 0.007). The posterior wall index had the highest discriminatory ability of all measured parameters, with a cutoff value of less than 0.9 (area under the curve [AUC] 0.84 [95% CI 0.76 to 0.91]) for a symptomatic acetabulum (sensitivity 72%, specificity 78%). Diagnostically useful parameters on CT scan to differentiate between symptomatic and asymptomatic hips were acetabular depth less than 22 mm (AUC 0.74 [95% CI 0.66 to 0.83]) and functional anteversion less than 19° (AUC 0.79 [95% CI 0.72 to 0.87]). Subtended angles with the highest accuracy to differentiate between symptomatic and asymptomatic hips were those at 105° (AUC 0.76 [95% CI 0.65 to 0.88]), 135° (AUC 0.78 [95% CI 0.70 to 0.86]), and 165° (AUC 0.77 [95% CI 0.69 to 0.85]) of the acetabular clockface.

CONCLUSION

An anatomical and functional acetabular anteversion of 24° and 22°, with a pelvic tilt of 10°, increases the acetabular opening and allows for more impingement-free flexion while providing sufficient posterosuperior coverage for loading. Hips with lower anteversion or a larger difference between anatomic and functional anteversion were more likely to be symptomatic. The importance of sufficient posterior coverage was also illustrated by the posterior wall indices and subtended angles at 105°, 135°, and 165° of the acetabular clockface having a high discriminatory ability to differentiate between symptomatic and asymptomatic hips. Future research should confirm whether integrating these parameters when selecting patients for hip preservation procedures can improve postoperative outcomes.Level of Evidence Level III, prognostic study.

The Proportion of Normalized Hips with Growth in Japanese Adolescents Aged > 10 years with Acetabular Dysplasia who Presented with Suspected Scoliosis

Background

If asymptomatic acetabular dysplasia (AD) is incidentally identified in adolescence, it is difficult to determine the appropriate follow-up or treatment strategy because the acetabulum is still developing. We investigated the rate of AD normalization at the end of acetabular growth.

Methods

This cross-sectional study involved 653 patients (1306 hips) aged 10-14 years with scoliosis or suspected scoliosis. All patients underwent plain standing whole-spine radiography (with the pelvis included) at the first visit. We measured the lateral center-edge angle, Sharp angle, Tönnis angle, and acetabular head index on radiographs. The criterion for AD was a lateral center-edge angle of < 20°. We extracted the data of patients aged < 12 (10-11) years and ≥ 12 (12-14) years with AD. Furthermore, we analyzed the radiographic follow-up data at 15 years of age to identify the AD normalization rate.

Results

AD was diagnosed in 19 hips from patients aged < 12 years and in 36 hips from patients aged ≥ 12 years. The AD normalization rate at 15 years of age was 31.6% in those diagnosed at < 12 years of age and 5.6% in those diagnosed at ≥ 12 years of age.

Conclusion

AD in adolescence was predictive of AD at the end of growth in 95% of cases diagnosed at ≥ 12 years of age compared with approximately 70% of cases diagnosed at < 12 years of age. Surgical treatment before completion of acetabular growth is beneficial for acetabular remodeling, but the decision to operate should be carefully evaluated in patients aged < 12 years.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s43465-023-01065-4.

Gait pattern analysis before and after periacetabular osteotomy in unilaterally affected dysplastic patients

BACKGROUND

Patients with acetabular dysplasia have an abnormal acetabular geometry which results in insufficient coverage of the femoral head. This coverage deficiency reduces contact surfaces within the joint, accelerating the wear of the articular cartilage and predisposing patients to early osteoarthritis. Periacetabular osteotomy is a surgical treatment of acetabular dysplasia that aims to reorient the acetabulum relative to the femoral head, increasing coverage.

METHODS

Pelvic kinematics and lower limbs joint kinematics and kinetics during the stance phase of gait were recorded using a 3D motion capture system and force plates, then compared pre- to post- and between limbs with a repeated measures 2-way ANOVA. Radiographic measurements and gait parameters were compared pre- to post-surgery using a t-test for dependant samples. To identify predictors of pelvic symmetry improvements during gait, a multivariate analysis was performed using a forward stepwise linear regression.

FINDINGS

Radiographic measurements improved for all participants while gait parameters remained unchanged. Hip flexion symmetry was improved following surgery. The external rotation moment of the healthy hip was reduced after surgery (-29%) resulting in increased asymmetry. Pelvic tilt was significantly greater on the affected side (+0.5°) during the loading response, and the difference tended to be greater after surgery (+0.8°).

INTERPRETATION

Unilaterally affected dysplastic patients have an asymmetrical gait pattern that is only partially corrected by periacetabular osteotomy even when radiographic and clinical targets are met. Differences between the limbs could be explained in part by a learned antalgic pattern and muscle weaknesses leading to complex compensation mechanisms.

In Vitro Investigation of Column Fixation Constructs for Periacetabular Osteotomy: Which Provide the Greatest Stiffness and Strength?

Background

Periacetabular osteotomy (PAO) is an effective surgical procedure for managing acetabular dysplasia. The purpose of this study was to analyze the biomechanical properties of novel PAO constructs that incorporate orthopaedic trauma techniques. We hypothesize that these fixation methods will create a stiffer construct that tolerates higher loads to failure.

Methods

Twenty bio-composite hemi-pelvises underwent PAO with the following fixation configurations: Group A: 4 iliac crest (IC) screws; Group B: 3 IC screws; Group C: 2 IC screws, 1 retrograde anterior column (AC) screw, and 1 lateral compression type-2 (LC2) screw directed from the anterior inferior iliac spine to the posterior inferior iliac spine; Group D: 1 AC screw, 1 LC2 screw, 1 posterior column screw; Group E: 2 LC2 screws, 1 AC screw. Constructs were loaded to failure on a material testing hydraulic press, and ultimate strength, stiffness, and osteotomy displacement were measured.

Results

The highest load to failure was seen in group D (2511 N), which was significantly more than groups A (1528 N, P = .0114) and B (1348 N, P < .0001). The stiffest construct was group E (602 N/mm) compared to groups A (315 N/mm, P = .0439) and B (243 N/mm, P = .0008). Failure occurred most often with a fracture in the posterior column.

Conclusions

This study supports column fixation methods used in orthopaedic trauma for PAO as biomechanically advantageous to traditional fixation techniques. These constructs may be beneficial to patients with weight-bearing concerns or early rehabilitation needs.

Perceived outcomes of periacetabular osteotomy

Aims

Social media is a popular resource for patients seeking medical information and sharing experiences. periacetabular osteotomy (PAO) is the gold-standard treatment for symptomatic acetabular dysplasia with good long-term outcomes. However, little is known regarding the perceived outcomes of PAO on social media. The aims of this study were to describe the perceived outcomes following PAO using three social media platforms: Facebook, Instagram, and X (formerly known as Twitter).

Methods

Facebook, Instagram, and X posts were retrospectively collected from 1 February 2023. Facebook posts were collected from the two most populated interest groups: "periacetabular osteotomy" and "PAO Australia." Instagram and X posts were queried using the most popular hashtags: #PAOwarrior, #periacetabularosteotomy, #periacetabularosteotomyrecovery, #PAOsurgery, and #PAOrecovery. Posts were assessed for demographic data (sex, race, location), perspective (patient, physician, professional organization, industry), timing (preoperative vs postoperative), and perceived outcome (positive, negative, neutral).

Results

A total of 1,054 Facebook posts, 1,003 Instagram posts, and 502 X posts were consecutively assessed from 887 unique authors. The majority (63.3%) of these posts were from patients in the postoperative period, with a median of 84 days postoperatively (interquartile range 20 to 275). The longest follow-up timeframe postoperatively was 20 years. Regarding perceived outcomes, 52.8% expressed satisfaction, 39.7% held neutral opinions, and 7.5% were dissatisfied. Most dissatisfied patients (50.9%) reported pain (chronic or uncontrolled acute) as an attributing factor.

Conclusion

Most PAO-perceived surgical outcomes on social media had a positive tone. Findings also indicate that a small percentage of patients reported negative perceived outcomes. However, dissatisfaction with PAO primarily stemmed from postoperative pain. Social media posts from other sources (physicians, hospitals, professional organizations, etc.) trend towards neutrality. Healthcare providers must consider the social media narratives of patients following PAO, as they may reveal additional outcome expectations and help improve patient-centred care, create informed decision-making, and optimize treatment outcomes.

The Influence of Patient Provider Educational Interactions and Associated Preoperative Variables on Outcomes in the Hip Dysplasia Population

Background

Patient provider interactions influence patient treatment adherence, clinical outcomes, patient satisfaction, and an overall patient's engagement in healthcare decisions. The purpose of this study was to examine the effectiveness of patient provider educational interactions and associated variables on patient reported outcomes in the hip dysplasia population.

Methods

A secondary data analysis was completed with 6-month postoperative survey data from participants, who had undergone periacetabular osteotomy. Data analysis including demographic variables, patient reported outcome results, and pre-operative knowledge retention.

Results

A significant difference was found between participants' expectations of crutch use and physical therapy care with actual performance (p<0.001 and p=0.01) and with engagement in pre-operative support based on mental health history (p=0.02).

Conclusion

Pre-operative interactions with a provider team and prior patients (pre-operative support) can influence a patient's educational experience. Providers should review educational interventions and offer pre-operative support to patients. Level of Evidence: VI.