Acetabular retroversion: Diagnosis and treatment

Functional and radiological outcomes of periacetabular osteotomy for hip dysplasia in patients under fifty years using a minimally invasive approach-a single surgeon series with a minimum follow up of two years

PURPOSE

We conducted a retrospective analysis of prospectively collected data to evaluate (1) the extent of surgical correction following minimally invasive periacetabular osteotomy, (2) improvements in functional outcomes and any potential predictors for favourable outcome, and (3) complications after minimally invasive periacetabular osteotomy.

METHODS

A total of 352 minimally invasive periacetabular osteotomy procedures were performed on 312 hip dysplasia patients between 2013 and 2020. Radiological parameters such as lateral centre edge angle, acetabular index, and Tönnis grade of arthritis were calculated. Patients also completed a range of patient reported outcome measures. Wilcoxon signed-rank tests were performed to assess for differences between patient reported outcome measures and radiological outcomes across the follow-up periods. Univariate linear regression and logistic regression were used to assess for predictors of change in functional outcome.

RESULTS

Patients had a significant correction in mean lateral centre edge angle from 17.2° to 35.3° (p < 0.001) and mean acetabular index from 13.2° to - 0.82°. At one year follow-up all patient reported outcome measures were significantly greater than their baseline measurements and this improvement was maintained at two years. Changes in patient reported outcome measures were independent of radiological parameters such as change in the lateral centre edge angle and acetabular index, pre-operative Tönnis grade, and patient factors such as age and sex. A total of 5.11% of patients developed post-operative complications, with four requiring posterior column fixation. Four patients (1.12%) needed a total hip replacement.

CONCLUSION

Minimally invasive periacetabular osteotomy is a safe procedure that provides significant functional outcome improvements following surgery at six months which is maintained at two years. More than three-fourths of patients achieved improvement of iHOT-12 score beyond the minimal clinically important difference and more than half of the patients achieved substantial clinical benefit for iHOT-12 score.

Three-Dimensional Reconstruction of Computed Tomography Imaging Is Not Reliable in Assessing Acetabular Rim Osteophytes or Acetabular Rim Pathology in Patients With Femoroacetabular Impingement

Purpose

To determine the reliability of 3-dimensional (3D) reconstruction of computed tomography (CT) imaging in evaluating acetabular rim morphology or acetabular rim osteophyte (ARO) existence and to group patients with femoroacetabular impingement (FAI) by ARO extent on coronal sections of CT and further compare clinical differences among groups.

Methods

Patients who underwent primary hip arthroscopy for FAI by the same surgeon between August 2016 and December 2018 with minimum 2-year follow-up were enrolled. The ARO was evaluated both on the acetabular gross anatomy (AGA) and coronal sections of CT, for its position, width (unit: mm), area (unit: mm2), and CT value (unit: HU). Patients were divided into 4 groups based on the extent of ARO on coronal CT: group A (ARO anterior to 12 o'clock), group P (ARO posterior to 12 o'clock), group AP (ARO across 12 o'clock), and group N (no ARO). Inter- and intraobserver correlation was analyzed. Demographic data, FAI deformity indicators on imaging, quantitative measurements of ARO, and pre- and postoperative patient-reported outcomes were compared among groups.

Results

There were 229 patients (229 hips) enrolled in total, 122 male (53.3%) and 107 female (46.7%), with a mean age of 37.2 ± 10.2 years. The correlation between 2 observers for grouping ARO using AGA was positive but poor (Kendall Tau-b coefficient = 0.157, P = .008). Moderate correlation was found between grouping based on AGA and coronal CT by the same observer (Kendall Tau-b coefficient = 0.482, P = .000). The patients were divided into 4 groups: 84 patients (36.7%) in group N, 2 patients (0.9%) in group A, 69 patients (30.1%) in group P, and 74 patients (32.3%) in group AP. Group N was younger in age (35.4 ± 10.7 years) than group P (39.6 ± 10.2 years) (P = 0.012) and had a larger proportion of women (57.1%) than group AP (36.5%) (χ2 = 6.869, P = .032). There was a greater proportion of positive posterior wall sign in group P (52.2%) than 48.6% for group AP and 33.3% for group N (χ2 = 6.397, P = .041). Group N had 61 (72.6%) Tönnis grade 0 hips compared with 37 (50%) in group AP (P = .014). No statistical significance was found among groups in pre- and postoperative α angle, lateral center-edge angle, and patient-reported outcomes. The widths of ARO in group AP for the 3 marked points from anterior to posterior were 3.88 ± 1.86, 4.84 ± 2.72, and 6.66 ± 3.18, separately (P＜.001); 15.73 ± 21.46, 19.22 ± 18.86, and 29.96 ± 17.05 for area (P＜.01); and 652.67 ± 214.12, 677.10 ± 274.81, and 728.84 ± 232.39 for CT value (P＜.05). For the ARO posterior to 12 o'clock, the group AP showed a larger width (6.66 ± 3.18), area (29.96 ± 17.05), and CT value (728.84 ± 232.39) than group P of (4.70 ± 2.25), (20.15 ± 12.91), and (641.84 ± 183.33) (P＜.001).

Conclusions

The evaluation of ARO on AGA is poor consistent with definite double-rim sign on coronal CT. There is a tendency of size-enlarging and density-increasing for ARO from anterior to posterior along the acetabular rim. Younger age, female gender, lower Tönnis grade, and negative posterior wall sign showed lower rate of ARO development.

Level of Evidence

Level IV, diagnostic case series.

Predicting Instability Risk Following Hemiarthroplasty for Femoral Neck Hip Fractures in Geriatric Patients

BACKGROUND

Although a rare complication, dislocation following hemiarthroplasty (HA) for a femoral neck hip fracture is associated with increased mortality, readmission, and possible revision surgery. To date many of the specific risk factors have been difficult to demonstrate. Patient factors, surgical factors, as well as morphological factors need to be assessed. Therefore, the purpose of this study was to elucidate the risk factors for dislocation of HA following femoral neck hip fractures in the geriatric population.

METHODS

This was a retrospective review of 270 patients who had hip fractures. Medical records between the years 2016 and 2022 informed binomial regression predictive models. The discriminative ability of variables in the final model and acetabular anteversion to predict dislocation was assessed with area under the curve (AUC) estimates.

RESULTS

Center edge angle (odds ratio 1.23), abduction angle (odds ratio 1.17), and depth width ratio (2.96e-11) were significant predictors of dislocation (P = .003, .028, and <.001, respectively). Center edge angle and depth width ratio (<44.1 ° and .298), respectively, were cut scores for risk. Dementia had a high discriminative of ability, as did men (AUC = 0.617, 0.558, respectively). Acetabular anteversion was not predictive of dislocation (P = .259) and theorized anteversion safe zones had poor discriminative ability with AUCs of 0.510 and 0.503, respectively.

CONCLUSIONS

Morphological factors related to hip dysplasia and a shallow acetabulum, which can be assessed with a radiograph alone, were found to be predictors of instability following HA in the elderly. Hemiarthroplasty implant design and manufacturer, and also acetabular version did not contribute to instability risk.

Global Acetabular Retroversion Is Not Associated With Differences in Outcomes After Primary Hip Arthroscopy Among Patients With Femoroacetabular Impingement Syndrome: A Matched Cohort Study With Minimum 5-Year Follow-Up

PURPOSE

To compare hip survivorship and patient-reported outcome measures (PROMs) after primary hip arthroscopy at 5-year follow-up between patients with femoroacetabular impingement syndrome (FAIS) with radiographic signs of global acetabular retroversion and those without.

METHODS

A retrospective matched-cohort study was conducted using a single-surgeon hip arthroscopy database. Patients were included if they underwent primary hip arthroscopy for treatment of FAIS, had preoperative hip x-rays, and had a minimum 5-year follow-up. Global retroversion was defined as the presence of ischial spine sign, posterior wall sign, and crossover sign on anteroposterior view. Patients with FAIS with global retroversion were matched 1:1 on age, sex, and body mass index to FAIS controls. The modified Harris Hip Score (mHHS) and Non-Arthritic Hip Score (NAHS) were administered preoperatively and at follow-up. Hip survivorship and PROMs were compared between the 2 groups using the paired t test, Wilcoxon signed rank test, and/or Cochran-Mantel-Haenszel test as appropriate. P values <.05 were considered significant.

RESULTS

Thirty-eight patients with global retroversion (mean age 40.6 ± 10.8 years, 60.5% female) were matched to 38 controls (mean age 41.3 ± 13.6 years, 60.5% female). Reoperation rates were the same in both groups (5.3%). On average, both groups reported significant pre- to postoperative improvement in mHHS (P < .001) and NAHS (P < .001), and there was no significant intergroup differences in the change in mHHS (P = .86) or NAHS (P = .90). Achievement rates for the patient acceptable symptom state on the mHHS were higher among males compared to females (P = .04) in both the global retroversion group (93.3% vs 73.9%) and the control group (93.3% vs 73.9%).

CONCLUSIONS

Patients with FAIS with and without global acetabular retroversion had no significant difference in outcomes after primary hip arthroscopy at a minimum 5-year minimum follow-up.

LEVEL OF EVIDENCE

Level III, retrospective comparative prognostic trial.

Femoroacetabular impingement - What the rheumatologist needs to know

Femoroacetabular impingement (FAI) syndrome is a common cause of hip and groin pain in young individuals. FAI syndrome is a triad of signs, symptoms, and imaging findings. Necessary but not sufficient for the diagnosis of FAI syndrome is the presence of cam and/or pincer morphology of the hip. However, pathological thresholds for cam and pincer morphologies are not well-established. Management of FAI syndrome is typically through either physiotherapist-led therapy or surgical intervention. Physiotherapist-led management involves exercises aimed to optimise movement patterns of the hip and pelvis to prevent impingement from occurring, activity modification and analgesia, whereas surgical management involves arthroscopic resection of the cam/pincer morphology and treatment of concomitant soft tissue pathologies such as labral tears, cartilage lesions or ligamentum teres tears. Careful consideration of intervention is required given that FAI syndrome may predispose those affected to developing future osteoarthritis of the hip. In most clinical trials, hip arthroscopy has been found to provide greater improvement in patient-reported outcomes in the short-term compared to physiotherapy, however it is unknown whether this is sustained in the long-term or affects the future development of hip osteoarthritis.

Patient positioning during the radiographic procedure affects the radiological signs of acetabular retroversion - A systematic review

Young adults presenting with non-traumatic hip pain may suffer from acetabular retroversion (AR). The previous studies have suggested that patient positioning during the radiographic procedure, that is, pelvic tilt and/or rotation may alter the appearance of the acetabulum. The purpose of this systematic review was to explore and collate existing literature on the correlation between pelvic positioning in weight-bearing anterior-posterior radiographs and the radiographic signs of AR, namely, the ischial spine sign (ISS) the cross-over sign (COS) and posterior wall sign (PWS). The preferred reporting items for systematic reviews and meta-analysis guidelines were followed. MEDLINE, EMBASE, PubMed, The Cochrane Library, and CINAHL were searched. The search string included the following keywords: Pelvic, tilt, rotation, positioning, inclination, incidence, AR, ISS, COS, PWS, and acetabular version. Two authors independently screened the studies identified in the search, extracted data, and critically assessed included studies for quality using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. In total, 2289 publications were screened. Fifteen articles were found eligible for full-text screening, and four articles met the inclusion criteria. Although the studies varied methodologically, all reported that pelvic positioning impacted radiographic signs of AR investigated. One study suggested that more than 9° of pelvic inclination would result in positive COS. No other benchmark values on the degree of pelvic tilt and rotation that would compromise the diagnosis of AR, that is, the detection of ISS, COS, and PWS were reported. At present, literature reporting on the correlation between patient positioning and AR is sparse. Four studies met the inclusion criteria, and they all reported a link between pelvic positioning and the radiographic appearance of AR.

Psychological Factors as Risk Contributors for Poor Hip Function after Periacetabular Osteotomy

Psychologic comorbidities have been identified as risk factors for poor outcomes in orthopedic procedures, but their influence on the outcome of hip-preserving periacetabular osteotomy (PAO) remains uncertain. This retrospective cohort study aimed to assess the impact of patients' psychological health on the outcome of PAO in patients with hip dysplasia (HD) and acetabular retroversion (AR). The study included 110 patients undergoing PAO for HD or AR between 2019 and 2021. Standardized questionnaires were administered to assess psychological factors, postoperative hip function, and activity level (mean follow-up: 25 months). Linear regression analyses were used to examine the associations between psychological factors and postoperative hip function and activity level. Both HD and AR patients showed improved postoperative hip function and activity levels. Linear regression analyses revealed that depression significantly impaired postoperative outcomes in both groups, whereas somatization negatively influenced the outcome in AR patients. General health perceptions significantly contributed to an improved postoperative outcome. These findings highlight the importance of concomitantly addressing psychologically relevant factors in order to improve patient outcomes after PAO procedures. Future prospective studies should continue to investigate the impact of various psychological factors and explore possibilities of incorporating psychological support into routine postoperative care for these patient cohorts.

Change in functional biomechanics following a targeted exercise intervention in patients with acetabular retroversion and femoroacetabular impingement syndrome

BACKGROUND

Acetabular retroversion is a form of hip dysplasia that may cause femoroacetabular impingement syndrome (FAIS), leading to pain and restricted hip range of motion. An exercise intervention aiming at altering pelvis tilt and related functional biomechanics may be a useful first-line intervention for patients who are not eligible for surgical repositioning.

RESEARCH QUESTION

Does squat and gait biomechanics change following an 8-week targeted exercise program in individuals with symptomatic acetabular retroversion and FAIS?

METHODS

This prospective intervention study used participants as their own controls. Examinations were conducted at three time-points: T1 baseline; T2 following an 8-week control period; T3 after 8 weeks' intervention. At each time-point, three-dimensional motion analysis of a deep squat and level gait was performed, and pain intensity was recorded using a numerical rating scale (NRS 0-10). The intervention consisted of a home-exercise program to improve core stability and pelvic movement. Differences in waveforms between time-points across pelvis and lower-limb biomechanics were evaluated using statistical parametric mapping. Delta (Δ, differences between T1-T2 and T2-T3) was used to evaluate changes in spatiotemporal gait parameters and pain.

RESULTS

Nineteen patients (18 females), mean age 22.6 (SD 4.5) years, BMI (kg/m2) 23.0 (SD 4.1), were included. Changes (Δ T1-T2 vs. Δ T2-T3) in squat biomechanics were observed as: (i) decreased anterior pelvic tilt, (ii) deeper vertical pelvis position, and (iii) increased knee flexion angle. Contrary, no significant changes in gait biomechanics, Δ walking speed, Δ step length, or NRS for pain were found.

SIGNIFICANCE

Following a targeted exercise intervention, participants were able to squat deeper, potentially allowing better hip function. The deepened squat position was accompanied by increased knee flexion and reduced anterior pelvic tilt. Gait biomechanics and patient-reported pain remained unchanged post-intervention. These findings are important for future design of exercise interventions targeting pelvic tilt in symptomatic individuals.

Acetabular retroversion does not affect outcome in primary hip arthroscopy for femoroacetabular impingement

PURPOSE

The surgical treatment of femoral-acetabular impingement syndrome (FAIS) in patients with acetabular retroversion (AR) is arthroscopical or by a reverse periacetabular osteotomy (PAO). The purpose of the present study was to investigate the results after arthroscopic treatment of FAIS in patients with and without radiographic signs of AR in a large, prospective cohort from the Danish Hip Arthroscopy Registry (DHAR). The hypothesis was there is no difference in clinical outcome between the two groups.

METHODS

Data on 4914 hip arthroscopies performed during 2012-2019 were obtained from DHAR. Patients with radiographic signs of osteoarthritis (Tönnis > 1), hip dysplasia (CEA < 25°), other hip pathologies or previous hip surgery were excluded. The clinical outcomes for patients with AR [defined by a positive posterior wall sign (PWS) in combination with a positive Ischial Spine Sign (ISS)] and patients without AR (no PWS, no ISS) were analyzed 1 and 2 years after surgery. The primary outcomes were the six domains of the Copenhagen Hip and Groin Outcome score (HAGOS), while secondary outcomes were the Hip Sports Activity Scale (HSAS), a visual analogue pain scale (VAS) and a numeric rating scale (NRS) for pain.

RESULTS

A total of 3135 hip arthroscopies were included, of which 339 had AR, 1876 did not, and 920 presented one of the two signs (PWS and ISS). There were no statistically significant differences 1 and 2 years after surgery (n.s.) between patients with and without AR in HAGOS domain scores, HSAS, VAS, or NRS. Both groups showed improvement at both follow-ups. The two groups did not differ in relation to intraoperative findings and the procedures they have had.

CONCLUSION

The outcome 1 and 2 years after arthroscopic treatment of FAIS is not different for patients with and without AR.

LEVEL OF EVIDENCE

III.

An Updated Review of Femoroacetabular Impingement Syndrome

Femoroacetabular impingement (FAI) is a chronic hip condition caused by femoral head and acetabular malformations resulting in abnormal contact across the joint. FAI often leads to labral, cartilaginous, and tissue damage that predispose this patient population to early osteoarthritis (OA). There are a variety of factors that increase the risk for FAI including younger age, Caucasian background, familial FAIS morphology, and competing in high-intensity sports during adolescence. Slow-onset, persistent groin pain is the most frequent initial presenting symptom. On physical examination, patients will typically have a positive FADIR test (flexion, adduction, internal rotation), also known as a positive impingement sign. FAI syndrome can be organized into three classifications; cam, pincer, or mixed. This classification refers to the characteristic morphological changes of the bony structures. The primary imaging modality for diagnosing FAI is a plain radiograph of the pelvis, which can be used to measure the alpha angle and the lateral center edge angle used to quantify severity. Conservative treatment is typically considered first-line treatment for mild to moderate FAI syndrome; however, the outcomes following postoperative surgical intervention have demonstrated excellent results. The most common surgical treatment option for FAI is done arthroscopically.

Evaluation of additional causes of hip pain in patients with femoroacetabular impingement syndrome

Femoroacetabular impingement syndrome (FAIS) is an increasingly prevalent pathology in young and active patients, that has contributing factors from both abnormal hip morphology as well as abnormal hip motion. Disease progression can be detrimental to patient quality of life in the short term, from limitations on sport and activity, as well as the long term through early onset of hip arthritis. However, several concurrent or contributing pathologies may exist that exacerbate hip pain and are not addressed by arthroscopic intervention of cam and pincer morphologies. Lumbopelvic stiffness, for instance, places increased stress on the hip to achieve necessary flexion. Pathology at the pubic symphysis and sacroiliac joint may exist concurrently to FAIS through aberrant muscle forces. Additionally, both femoral and acetabular retro- or anteversion may contribute to impingement not associated with traditional cam/pincer lesions. Finally, microinstability of the hip from either osseous or capsuloligamentous pathology is increasingly being recognized as a source of hip pain. The present review investigates the pathophysiology and evaluation of alternate causes of hip pain in FAIS that must be evaluated to optimize patient outcomes.

A Statistical Shape Model-Based Analysis of Periacetabular Osteotomies: Technical Considerations to Achieve the Targeted Correction

BACKGROUND

Classic and reverse Bernese periacetabular osteotomy (PAO) have been shown to be effective for the treatment of developmental dysplasia of the hip (by classic PAO), severe acetabular retroversion (by reverse PAO), and some protrusio acetabuli (by reverse PAO). Especially in severe cases with higher degrees of correction, a relevant overlap between the osteotomized fragment and the pelvis might occur, leading to necessary fragment translation. The aim of the present study was to analyze the necessary translation as a function of the degree of correction using a statistical mean model of the pelvis according to the technique (classic PAO or reverse PAO).

METHODS

A mean statistical shape model of the pelvis and 2 extreme models were used to simulate rotation of the osteotomized fragment during a classic or reverse PAO and to calculate rotations from -20° to 20° in the frontal, sagittal, and transverse planes and a combination thereof. The depth and volume of the intersection between the mobilized fragment and the pelvis were calculated, and the minimum translation of the fragment necessary to avoid segment overlap was determined.

RESULTS

The maximum intersection distances between the pelvis and the 20° rotated fragment were 6.7 and 15.3 mm for adduction and abduction (frontal plane), 6.4 and 4.5 mm for internal and external rotation (transverse plane), and 27.8 and 9.2 mm for extension and flexion (sagittal plane). The necessary translations for 20° of fragment rotation were 7.0 and 12.8 mm for adduction and abduction (frontal plane), 4.8 and 5.0 mm for internal and external rotation (transverse plane), and 18.5 mm and 8.8 mm for extension and flexion (sagittal plane).

CONCLUSIONS

Acetabular reorientation with the classic or reverse PAO results in translation of the fragment and in a consequent change in the rotational center. This finding is more pronounced with higher degrees of fragment reorientation in abduction and extension; it becomes especially pronounced in reverse PAO for acetabular retroversion or protrusio acetabuli, and might limit the ability to achieve the intended improvement in overall hip biomechanics.

Association between femoroacetabular impingement syndrome and limited lateral hip rotation in young athletes: A case-control study

PURPOSE

Hip pain is very common in athletes. One of the main disorders causing hip pain is femoroacetabular impingement syndrome. This study aimed to identify a new etiological risk factor for femoroacetabular impingement in the hip.

METHODS

This case-control study included 88 young athletes, 34 with pains in the hip (supposedly with femoroacetabular impingement) and 54 controls. Femoroacetabular impingement was diagnosed with a flexion, adduction, internal, and rotation test and a particular type of hip pain during sports activities. The medial (internal) and lateral (external) hip ranges of rotation have been measured with an inclinometer. The data were analyzed using a t-test, the Wilcoxon test, the Mann-Whitney U test, and logistic regression.

RESULTS

There is a statistically significant difference in the external hip rotation range between the athletes with hip pain and controls. Logistic regression analysis showed that external hip range of motion is significantly associated with femoroacetabular impingement.

CONCLUSION

Limited external hip range of motion was found to be significantly associated with the diagnosis of femoroacetabular impingement in young athletes. A biomechanical explanation of the hypothesis that limited external hip rotation can predict femoroacetabular impingement is given. Based on our results, the hip's lateral range of motion screening can be advised within the regular screening of young athletes. Kinesiotherapeutic procedures for stretching the muscles of the medial hip rotors can be advised to prevent the lateral hip rotation restriction and lower the risk of femoroacetabular impingement in case the limited rotation is due to muscular restriction.

LEVEL OF EVIDENCE

level III-case-control study.

Acetabular retroversion is prevalent and proportional to the severity of slipped upper femoral epiphysis

Aims

Slipped upper femoral epiphysis (SUFE) has well documented biochemical and mechanical risk factors. Femoral and acetabular morphologies seem to be equally important. Acetabular retroversion has a low prevalence in asymptomatic adults. Hips with dysplasia, osteoarthritis, and Perthes’ disease, however, have higher rates, ranging from 18% to 48%. The aim of our study was to assess the prevalence of acetabular retroversion in patients presenting with SUFE using both validated radiological signs and tomographical measurements.

Methods

A retrospective review of all SUFE surgical cases presenting to the Royal Children’s Hospital, Melbourne, Australia, from 2012 to 2019 were evaluated. Preoperative plain radiographs were assessed for slip angle, validated radiological signs of retroversion, and standardized postoperative CT scans were used to assess cranial and mid-acetabular version.

Results

In all, 116 SUFEs presented in 107 patients who underwent surgical intervention; 47 (52%) were male, with a mean age of 12.7 years (7.5 to 16.6). Complete radiological data was available for 91 patients (99 hips) with adequate axial CT imaging of both hips. Overall, 82 patients (82%) underwent pinning in situ (PIS), with subcapital realignment surgery (SRS) performed in 17 patients (18%) (slip angles > 75°). Contralateral prophylactic PIS was performed in 72 patients (87%). On the slip side, 62 patients (68%) had one or more radiological sign of retroversion. Tomographical acetabular retroversion was more pronounced cranially than caudally of the acetabulum on both the affected side and the contralateral side (p < 0.001) as expected in the normal population. Increasing severity of the slip was found to be directly proportional to the degree of reduction in cranial and central acetabular version (p < 0.05) in the SUFE hips.

Conclusion

Acetabular retroversion is more prevalent in patients with SUFE than previously reported, and have been shown be correlated to the severity of the slip presentation. The presence of radiological signs of acetabular retroversion could be used to justify prophylactic contralateral pinning.

Cite this article: Bone Jt Open 2022;3(2):158–164.

Retroversion of the hemipelvis rather than hypoplastic posterior wall decreases acetabular anteversion in hips affected by Perthes disease

The acetabular retroversion has a moderate incidence of 31-60% in all patients of the Perthes disease. It might be caused by posterior wall dysplasia based on recent animal researches. However, some studies support that hemipelvic retroversion is the main factor for the acetabular retroversion. The primary pathological factor of increasing retroversion angle is still controversial anatomically. This study aimed to identify whether there is acetabular retroversion in children with Perthes disease,and to find a method to distinguish version types. Forty children with unilateral Perthes disease who were admitted to our hospital from January 1, 2012 to December 31, 2018 were enrolled, and 40 controls were matched based on sex and age. The acetabular anteversion angle (AAA), internal wall anteversion angle (IWAA), anterior wall height of the acetabulum (A), acetabular posterior wall height (P), and acetabular width (W) were assessed on computed tomography (CT) at the level of the femoral head center. The acetabular wall difference index (AWDI; AWDI = P-A)/W*100) was calculated. The mean AAA was significantly lower in Perthes disease hips (10.59 (8.05-12.46)) than in contralateral hips (12.04 (9.02-13.33)) (p = 0.002) but did not differ from control hips (9.68 ± 3.76) (p = 0.465). The mean IWAA was significantly lower in Perthes hips (9.16 ± 3.89) than in contralateral hips (11.31 ± 4.04) (p = 0.000) but did not differ from control hips (9.43 ± 3.82) (p = 0.753). The mean AWDI did not differ between Perthes hips (0.41 ± 4.94) and contralateral hips (- 1.12 (- 4.50, 2.17)) (p = 0.06) or control hips (- 0.49 ± 5.46) (p = 0.437). The mean W was significantly higher in Perthes hips (44.61 ± 5.06) than in contralateral hips (43.36 ± 4.38) (p = 0.000) but did not differ from control hips (45.02 ± 5.01) (p = 0.719). The mean A and P did not differ between Perthes hips and contralateral hips or control hips. Correlation analysis of all hip joints revealed a significant correlation between AAAs and IWAAs (r = 0.772; r = 0.643; r = 0.608; and r = 0.540). Linear regression analysis revealed that AAAs increased with IWAAs. Multiple linear regression showed that IWAAs and AWDIs have good predictive value for AAAs in both Perthes and control hips (R² = 0.842, R² = 0.869). In patients with unilateral Perthes disease, the affected acetabulum is more retroverted than that on the contralateral side, which may be caused by hemipelvic retroversion. The measurements in this study could distinguish the form of acetabular retroversion. IWAAs and AWDIs can be used as new observations in future studies of acetabular version.

Which anatomical conditions are associated with limitations of the hip function after SCFE?

Background

Patients sustained a slipped capital femoral epiphysis (SCFE) might have symptoms beyond their stabilization surgery in the childhood.

Methods

35 patients with a SCFE were treated in our clinic and available for a clinical follow-up. The results were compared in dependence of the presence of dysplasia, acetabular retroversion or a FAI type CAM.

Results

A FAI type CAM led to significant inferior results (p < 0.05), especially in combination with a retroversion.

Conclusions

The clinical outcome seemed to be influenced by the presence of a FAI type CAM or a combination with a retroversion, which might aggravate the femoro-acetabular conflict.

Level of evidence

III, retrospective.

Iliac anatomy in women with developmental dysplasia of the hip: Measurements using three-dimensional computed tomography

Background

We aimed to clarify the iliac anatomy in developmental dysplasia of the hip using three-dimensional computed tomography.

Methods

The distance between two points along each anatomical portion of the ilium, including the acetabular center, were compared between patients in the dysplasia and control groups.

Results

There were no significant differences in the upper part of the ilium between the groups. However, three distances that included the acetabular center were significantly shorter in the dysplasia group than in the control group.

Conclusions

Our study suggests that bone dysplasia occurs in the ilium near the acetabulum, not in the iliac wings.

Correlation of Patient-Reported Outcomes After Periacetabular Osteotomy With Femoral Head Coverage and Acetabular Orientation: A Single-Center Cohort Study

BACKGROUND

Gaining a better understanding of the underlying pattern of acetabular dysplasia 3-dimensionally can help better guide treatment and optimize clinical outcomes after periacetabular osteotomy (PAO).

PURPOSE

(1) To examine the relationship between femoral head coverage before and after PAO for dysplasia and patient-reported outcome measure (PROM) scores and (2) to assess if the direction/orientation of correction of the acetabulum can be predicted based on the Ottawa classification.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective analysis of a prospectively collected database from a single-center institutional registry of PAO was conducted, and PROM scores at a minimum of 2 years were analyzed. A total of 79 hips (67 patients [56 female]; mean age at surgery, 27.5 years [range, 15.8-53.7 years]) were available for inclusion. According to the Ottawa classification, 54 hips (68.4%) had global deficiency, 15 hips (18.9%) had posterior deficiency, and 10 hips (12.7%) had anterior deficiency. Hip2Norm software was used to analyze the 3-dimensional coverage of the femoral head. Statistical analysis was conducted to look at significant predictors of improvements in PROMs using the minimal clinically important difference (MCID) for the Hip disability and Osteoarthritis Outcome Score (HOOS) Activities of Daily Living subscale.

RESULTS

At a mean follow-up of 3.1 years (range, 2.0-7.4 years), all functional outcome scores improved significantly. A postoperative total femoral coverage <75.7%, posterior coverage (PC) <45.2%, and femoral head extrusion index >15.5% were all associated with not reaching the MCID for the HOOS Activities of Daily Living subscale. Multivariate analysis showed that PC was the single most important significant modifier influencing functional outcomes after PAO for the treatment of acetabular dysplasia, with an odds ratio of 6.0 (95% CI, 1.8-20.4; P = .004). One-way analysis of variance showed a significant difference comparing the mean change in radiographic measurements, that is, anterior coverage, PC, and total femoral coverage, per the Ottawa classification (P < .001).

CONCLUSION

Our study demonstrated that postoperative femoral head coverage and acetabular orientation were significant predictors of PROM scores. Classifying acetabular dysplasia into 3 groups based on the plane of instability could optimize the planning of PAO by giving a better understanding of the 3-dimensional deformity.

Outside-In Capsulotomy of the Hip for Arthroscopic Pincer Resection

Hip surgical techniques have evolved significantly, transitioning from open techniques to arthroscopic techniques. Hip arthroscopy has many advantages over open techniques, including reduced trauma to surrounding tissues, reduced risk of infection, and improved patient-reported outcome measures. Hip arthroscopic techniques are now commonly used for pathologies such as femoroacetabular impingement (FAI). FAI can include cam, pincer, or mixed impingement. Through hip arthroscopy, FAI may be treated with a femoroplasty and acetabuloplasty along with addressing any labral pathology that may exist. Owing to the capsule playing an integral role in hip stability, surgeons are now mindful of the initial approach and closure on completion of the intra-articular procedure. The most common approach for capsulotomy is the inside-out approach. However, this approach can be difficult in patients with a large pincer deformity. The authors describe an outside-in approach to arthroscopic hip capsulotomy. This capsular approach helps protect the labrum and articular cartilage while preserving capsular tissue.

A comparative radiographic morphometric analysis to assess the normal radiological morphology of the adult hip in indian population

OBJECTIVE

Our objective is to analyze the normal radiological morphologic parameters of the adult hip joint of the Indian population and compare it with standard measurements and with other populations to assess the variations.

METHODS

A prospective analysis of the normal pelvis X-rays of 800 persons (1600 hips) was done. We have calculated the acetabular inclination, acetabular index, lateral center edge angle (LCEA) and neck-shaft angle (NSA), sphericity of the femoral head, congruity of the joint, version of the acetabulum, depth of acetabulum, and lateralization of the femoral head in normal X-rays of the pelvis in adult persons. We used RadiAnt DICOM viewer version 4.6.5.18450 (64bit) for measurement. Statistical analysis and mean values were calculated using SPSS software.

RESULTS

There were 978 X-rays of the male hip and 622 female. The acetabular inclination varied from 1 to 9. The mean acetabular index was 26.5. The LCEA was between 20 and 50. The mean neck-shaft angle was 133. There were 35, hips with an aspherical head. 94.2% X-rays the hip joint was congruent. There was 2.9% of the retroversion of acetabulum, 3.3% lateralization.

CONCLUSION

Most of the parameters were comparable to standard values the acetabular index was lower. LCEA and NSA were higher. The acetabular angle was lower. There were femoral head asphericity, joint incongruity, and lateralization of the femoral head in a small proportion of our general population.

Does pain and hip function improve 2 years after reverse periacetabular osteotomy? A follow-up study of 74 patients

Data on outcome in patients with acetabular retroversion (AR) treated with reverse periacetabular osteotomy (reverse PAO) are sparse. The aim of the study was to investigate changes in pain and hip function among patients with AR 2 years after reverse PAO and to examine whether changes in pain were associated with changes in hip function. In addition, to evaluate patient satisfaction and changes in quality of life (QoL). We present a prospective follow-up study with patient-reported outcome data from Aarhus University Hospital in Denmark. Pain at rest and during activity was measured with a Visual Analogue Scale (VAS), hip function with the Hip disability and Osteoarthritis Outcome Score (HOOS) and QoL with the Short-Form 36, pre-operatively and 2 years after reverse PAO in 74 patients. Changes were analysed using paired t-test and multiple linear regressions. Significant and clinically relevant mean improvements in pain and hip function were found. The numbers of responders achieving a minimal clinically important difference varied from 51 to 73%. Positive significant association between changes in pain and changes in hip function were found. Significant mean improvement in QoL was found. The study had a loss to follow-up of 23%. Two years after reverse PAO, patients diagnosed with AR showed significant and clinically relevant mean improvements in pain and hip function. Decreased pain was significantly associated with improved hip function. The majority of patients were satisfied with the result of surgery and QoL was similar to the Danish background population.