What Mid-term Patient-reported Outcome Measure Scores,Reoperations, and Complications Are Associated with Concurrent Hip Arthroscopy and Periacetabular Osteotomy to Treat Dysplasia with Associated Intraarticular Abnormalities?

BackgroundPeriacetabular osteotomy (PAO) is a well-accepted treatment for acetabular dysplasia, but treatment success is not uniform. Concurrent hip arthroscopy has been proposed for select patients to address intraarticular abnormalities. The patient-reported outcomes, complications, and reoperations for concurrent arthroscopy and PAO to treat acetabular dysplasia remain unclear.Questions/purposes(1) What are the functional outcome scores among select patients treated with PAO plus concurrent hip arthroscopy at mid-term follow-up? (2) What factors are associated with conversion to THA or persistent symptoms (modified Harris hip score ≤ 70 or WOMAC pain subscore ≥ 10)? (3) What proportion of patients underwent further hip preservation surgery at mid-term follow-up? (4) What are the complications associated with the procedure?MethodsBetween November 2005 and December 2012, 78 patients (81 hips) who presented with symptomatic acetabular dysplasia—defined as a lateral center-edge angle less than 20° with hip pain for more than 3 months that interfered with daily function—had undergone unsuccessful nonsurgical treatment, had associated intraarticular abnormalities on MRI, and underwent combined hip arthroscopy and PAO. Eleven patients did not have minimum 4-year follow-up and were excluded, leaving 67 patients (70 hips) who met our inclusion criteria and had a mean follow-up duration of 6.5 ± 1.6 years. We retrospectively evaluated patient-reported outcomes at final follow-up using the University of California Los Angeles (UCLA) activity score, the modified Harris Hip Score (mHHS), and the WOMAC pain subscore. Conversion to THA or persistent symptoms were considered clinical endpoints. Repeat surgical procedures were drawn from a prospectively maintained database, and major complications were graded according to the validated Clavien-Dindo classification (Grade III or IV). Student t-tests, chi-square tests, and Fisher exact tests identified the association of patient factors, radiographic measures, and surgical details with clinical endpoints. For patients who underwent bilateral procedures, only the first hip was included in our analyses.ResultsAt final follow-up, the mean mHHS for all patients improved from a mean ± SD of 55 ± 19 points to 85 ± 17 points (p < 0.001), the UCLA activity score improved from 6.5 ± 2.7 points to 7.5 ± 2.2 points (p = 0.01), and the WOMAC pain score improved from 9.1 ± 4.3 points to 3.2 ± 3.9 points (p < 0.001). Three percent (2 of 67) of patients underwent subsequent THA, while 21% (15 of 70) of hips were persistently symptomatic, defined as mHHS less than or equal to 70 or WOMAC pain subscore greater than or equal to 10. Univariate analyses indicated that no patient demographics, preoperative or postoperative radiographic metrics, or intraoperative findings or procedures were associated with subsequent THA or symptomatic hips. Worse baseline mHHS and WOMAC pain scores were associated with subsequent THA or symptomatic hips. Seven percent (5 of 67) of patients underwent repeat hip preservation surgery for recurrent symptoms, and 4% (3 of 67) of patients had major complications (Clavien-Dindo Grade III or IV).ConclusionThis study demonstrated that concurrent hip arthroscopy and PAO to treat symptomatic acetabular dysplasia (with intraarticular abnormalities) has good clinical outcomes at mid-term follow-up in many patients; however, persistent symptoms or conversion to THA affected almost a quarter of the sample. We noted an acceptable complication profile. Further study is needed to directly compare this approach to more traditional techniques that do not involve arthroscopy. We do not use isolated hip arthroscopy to treat symptomatic acetabular dysplasia.Level of EvidenceLevel IV, therapeutic study.     

Similar Clinical Outcomes for THAs With and Without Prior Periacetabular Osteotomy

Introduction

Some patients opt to undergo conversion to a THA for continued pain or progression of hip arthritis after periacetabular osteotomy. Whether patients are at greater risk for postoperative complications, revision THA, poor clinical outcomes, or compromised radiographic results after periacetabular osteotomy is debatable.

Questions/purposes

When compared with a matched cohort of patients who underwent THAs for developmental dysplasia of the hip (DDH) without previous periacetabular osteotomy, we asked whether a THA after a periacetabular osteotomy has (1) a higher complication rate, (2) a higher likelihood of resulting in revision THA, (3) comparable improvements in Harris hip score, and (4) comparable radiographic results.

Patients and Methods

A multicenter retrospective review of 562 patients undergoing 645 periacetabular osteotomies was performed. Twenty-three hips in 22 patients underwent a THA after periacetabular osteotomy. The patients were matched for age, sex, and BMI with 23 hips in 23 patients with DDH undergoing THA without a history of periacetabular osteotomy. Minimum followup for both groups of patients was 2 years (mean, 10 ± 4 years and 6 ± 4 years, respectively). Comparisons were made to answer the study questions based on a retrospective review from prospectively maintained registries of clinical and radiographic information at two participating centers.

Results

With the numbers available, there was no difference in complication or revision rates between the two groups (p = 0.489 and 1.000, respectively); however, a post hoc power analysis showed our study was underpowered to detect a difference in the rate of postoperative complications or revision THA. There was marked improvement in Harris hip score with THA after periacetabular osteotomy (p < 0.001) and THA for DDH (p < 0.001), but there was no difference (p = 0.265) in the Harris hip score at final followup between either group. The acetabular component was placed at a mean of 17° more retroversion during THA after periacetabular osteotomy compared with THA for DDH (p = 0.002).

Conclusions

This study did not detect any differences in the clinical outcomes in patients undergoing THA after periacetabular osteotomy done with a modern abductor-sparing approach when compared with a matched cohort undergoing THA for DDH. However, even with patients tallied across two high-volume centers during nearly 15 years, our study was underpowered to detect potentially important differences between the THA after periacetabular osteotomy group and the THA for DDH group. The data in this report are suitable as pilot data for future studies and for systematic reviews. Larger multicenter studies are needed to understand how the technical challenges of THA after periacetabular osteotomy affect postoperative complications and revision THA.

Level of Evidence

Level III, therapeutic study.     

What Are the Radiographic Reference Values for Acetabular Under- and Overcoverage?

BackgroundBoth acetabular undercoverage (hip dysplasia) and overcoverage (pincer-type femoroacetabular impingement) can result in hip osteoarthritis. In contrast to undercoverage, there is a lack of information on radiographic reference values for excessive acetabular coverage.Questions/purposes(1) How do common radiographic hip parameters differ in hips with a deficient or an excessive acetabulum in relation to a control group; and (2) what are the reference values determined from these data for acetabular under- and overcoverage?MethodsWe retrospectively compared 11 radiographic parameters describing the radiographic acetabular anatomy among hip dysplasia (26 hips undergoing periacetabular osteotomy), control hips (21 hips, requiring no rim trimming during surgical hip dislocation), hips with overcoverage (14 hips, requiring rim trimming during surgical hip dislocation), and hips with severe overcoverage (25 hips, defined as having acetabular protrusio). The hips were selected from a patient cohort of a total of 593 hips. Radiographic parameters were assessed with computerized methods on anteroposterior pelvic radiographs and corrected for neutral pelvic orientation with the help of a true lateral radiograph.ResultsAll parameters except the crossover sign differed among the four study groups. From dysplasia through control and overcoverage, the lateral center-edge angle, acetabular arc, and anteroposterior/craniocaudal coverage increased. In contrast, the medial center-edge angle, extrusion/acetabular index, Sharp angle, and prevalence of the posterior wall sign decreased. The following reference values were found: lateral center-edge angle 23° to 33°, medial center-edge angle 35° to 44°, acetabular arc 61° to 65°, extrusion index 17% to 27%, acetabular index 3° to 13°, Sharp angle 38° to 42°, negative crossover sign, positive posterior wall sign, anterior femoral head coverage 15% to 26%, posterior femoral head coverage 36% to 47%, and craniocaudal coverage 70% to 83%.ConclusionsThese acetabular reference values define excessive and deficient coverage. They may be used for radiographic evaluation of symptomatic hips, may offer possible predictors for surgical outcomes, and serve to guide clinical decision-making.

Level of Evidence

Level III, diagnostic study.     

Evaluation of Acetabular Development Following Open Reduction of Developmental Dysplasia of Hip in Children After Walking Age

Background and purposeThe growth and development of the acetabulum in children with developmental dysplasia of hip (DDH) depends upon the extent of concentric reduction. Children in walking age often need open reduction with or without additional osteotomies to obtain congruous, stable reduction. The purpose of this study was to evaluate acetabular development in late diagnosed DDH treated by open reduction with or without femoral osteotomy.MethodsThis is a retrospective study of 29 children (40 hips) with idiopathic DDH, previously untreated managed by open reduction with or without femoral osteotomy. We analyzed preoperative and yearly postoperative radiographs up to 6 years of age for acetabular development by measuring acetabular index. Acetabular remodeling was assessed with a graphical plot of serial mean acetabular index. Those with AI < 30° at outcome measure point of 6 years of patient age were considered to have satisfactory acetabular remodeling.ResultsMean age of surgery was 26.8 months. Open reduction alone was done in 14 hips and open reduction with concurrent femoral osteotomy done in 26 hips. The mean acetabular index pre operatively was 36.6° ± 5.9° which reduced to 29.7° ± 6° at 1-year follow-up and to 26.6° ± 5.9° at 2-year follow-up. 28 out of 40 hips were available for evaluation at outcome measure point of 6 years of age, which showed satisfactory remodeling in 24 hips with mean AI of 22.7° ± 5.7°. Maximum acetabular development was seen at 2 years post-surgery and better remodeling was seen in children operated at less than 2 years of age. 5 hips had changes of avascular necrosis of femoral head. There was no incidence of redislocation/subluxation at latest follow-up.ConclusionOpen reduction in late-diagnosed developmental dysplasia of hip has potential for favourable acetabular development. Femoral osteotomy when required along with open reduction may suffice to address acetabular dysplasia found in the initial years of management of DDH.     

Factors Associated With Abnormal Joint Contact Pressure After Periacetabular Osteotomy: A Finite-Element Analysis

BackgroundIdentifying factors associated with poor hip contact mechanics after periacetabular osteotomy (PAO) may help surgeons optimize acetabular corrections in individual patients. We performed individual-specific finite-element analyses to identify preoperative morphological and surgical correction factors for abnormal contact pressure (CP) after PAO.MethodsWe performed finite-element analyses before and after PAO with reference to the standing pelvic position on individual-specific 3-dimensional hip models created from computed tomography images of 51 dysplastic hips. Nonlinear contact analyses were performed to calculate the joint CP of the acetabular cartilage during a single-leg stance.ResultsThe maximum CP decreased in 50 hips (98.0%) after PAO compared to preoperative values, and the resulting maximum CP was within the normal range (<4.1 MPa) in 33 hips (64.7%). Multivariate analysis identified the roundness index of the femoral head (P = .002), postoperative anterior center-edge angle (CEA; P = .004), and surgical correction of lateral CEA (Δlateral CEA; P = .003) as independent predictors for abnormal CP after PAO. A preoperative roundness index >54.3°, a postoperative anterior CEA <36.3°, and a Δlateral CEA >27.0° in the standing pelvic position predicted abnormal CP after PAO.ConclusionPAO normalized joint CP in 64.7% of the patients but was less likely to normalize joint CP in patients with aspheric femoral heads. Successful surgical treatment depends on obtaining adequate anterior coverage and avoiding excessive lateral correction, while considering the physiological pelvic tilt in a weight-bearing position.     

Prominent Anterior Inferior Iliac Spine Morphologies Are Common in Patients with Acetabular Dysplasia Undergoing Periacetabular Osteotomy

BackgroundThe anterior inferior iliac spine (AIIS) prominence is increasingly recognized in the setting of femoroacetabular impingement (FAI). The AIIS prominence may contribute to decreased hip flexion after acetabular reorientation in patients with acetabular dysplasia. AIIS morphologies have been characterized in numerous populations including asymptomatic, FAI, and athletic populations, but the morphology of the AIIS in patients with symptomatic acetabular dysplasia undergoing periacetabular osteotomy (PAO) has not been studied. In acetabular dysplasia, deficiency of the anterosuperior acetabular rim is commonly present and may result in the AIIS being positioned closer to the acetabular rim. Understanding morphological variation of the AIIS in patients with symptomatic dysplasia, and its relationship to dysplasia subtype and severity may aid preoperative planning, surgical technique, and evaluation of postoperative issues after PAO.Questions/purposesIn this study, we sought to determine: (1) the variability of AIIS morphology types in hips with symptomatic acetabular dysplasia and (2) whether the differences in the proportion of AIIS morphologies are present between dysplasia pattern and severity subtypes.MethodsUsing our hip preservation database, we identified 153 hips (148 patients) who underwent PAO from October 2013 to July 2015. Inclusion criteria for the current study were (lateral center-edge angle [LCEA] < 20°), Tönnis Grade of 0 or 1 on plain AP radiographs of the pelvis, preoperative low-dose CT scan, and no prior surgery, trauma, neuromuscular, ischemic necrosis, or Perthes-like deformity. A total of 50 patients (50 hips) with symptomatic acetabular dysplasia undergoing evaluation for surgical planning of PAO remained for retrospective evaluation; we used these patients’ low-dose CT scans for analysis. The median (range) age of patients in the study was 24 years (13 to 49). Ninety percent (45 of 50) of the hips were in female patients, whereas 10% (5 of 50) were in male patients. The morphology of the AIIS was classified on three-dimensional CT reconstructions according to a previously published classification to define the relationship between the AIIS and the acetabular rim. The morphology of the AIIS was classified as Type I (AIIS well proximal to acetabular rim), Type II (AIIS extending to level of acetabular rim), or Type III (AIIS extending distal to acetabular rim). Acetabular dysplasia subtype was characterized according to a prior protocol as either predominantly an anterosuperior acetabular deficiency, a posterosuperior acetabular deficiency, or a global acetabular deficiency. Acetabular dysplasia severity was distinguished as mild (LCEA 15° to 20°) or moderate/severe (LCEA < 15°). To answer our first question, regarding the proportions of each AIIS morphology in the dysplasia population, we calculated proportions and 95% CI estimates. To answer our second question, regarding the proposition of AIIS type between subtypes of dysplasia type and severity, we used a chi-square test or Fisher’s exact test to compare categorical variables. A p value of < 0.05 was considered significant.ResultsSeventy-two percent (36 of 50; 95% CI 58% to 83%) of patients had a Type II or III AIIS morphology. Type I AIIS morphology was found in 28% of patients (14 of 50; 95% CI 18% to 42%), Type II AIIS morphology in 62% (31 of 50; 95% CI 48% to 74%), and Type III AIIS/morphology in 10% (5 of 50; 95% CI 4% to 21%). A Type I AIIS was seen in seven of 15 of patients with anterosuperior acetabular deficiency, three of 18 of patients with global deficiency, and four of 17 patients with posterosuperior deficiency (p = 0.08). There was no difference in the variability of AIIS morphologies between the different subtypes of acetabular dysplasia pattern and no difference in AIIS morphology variability between patients with mild versus moderate/severe dysplasia.ConclusionsThe morphology of the AIIS in patients with acetabular dysplasia is commonly prominent, with 72% of hips having Type II or Type III morphologies.Clinical RelevanceThe AIIS is often prominent in patients with acetabular dysplasia undergoing PAO, regardless of dysplasia pattern or severity. Prominent AIIS morphologies may affect hip flexion ROM after acetabular reorientation. AIIS morphology is a variable that should be considered during preoperative planning for PAO. Future studies are needed to assess the clinical significance of a prominent AIIS on intraoperative findings and postoperative status after PAO.     

Does Surgical Hip Dislocation and Periacetabular Osteotomy Improve Pain in Patients With Perthes-like Deformities and Acetabular Dysplasia?

BackgroundPatients with symptomatic residual Perthes-like deformities may present with a combination of structural abnormalities including a large aspheric femoral head, short and wide femoral neck, high greater trochanter, and acetabular dysplasia. Sometimes, the hip is further compromised by concurrent symptomatic femoroacetabular impingement (FAI) (proximal femoral deformities) and structural instability (acetabular dysplasia).Questions/purposesWe therefore sought to characterize (1) the intraoperative findings; (2) radiographic correction; and (3) early patient-reported outcomes, complications, and failures of treating complex Perthes-like hip deformities with combined surgical dislocation and periacetabular osteotomy (PAO).MethodsWe performed 694 hip preservation procedures between November 2006 and August 2010. Of these, 46 had residual Perthes-like hip deformities, defined as proximal deformity consistent with residual Perthes and a history of Perthes disease or treatment of pediatric hip dysplasia. Of these, we report on 16 patients (16 hips) with residual Perthes-like hip deformities and associated acetabular dysplasia (structural instability, defined as radiographic evidence of acetabular dysplasia with intraoperative confirmation of instability). These 16 patients were treated with a combined surgical hip dislocation to comprehensively address intraarticular and extraarticular sources of FAI and PAO to address structural instability and were analyzed at a minimum 24-month followup (median, 40 months; range, 24–78 months). No patients in this series were lost to followup. Ten patients’ hips had previous surgical treatment, including six with previous osteotomy. Operative findings were extracted from standardized prospectively collected intraoperative data collection forms. Radiographic correction was evaluated with established methods (lateral center-edge angle, anterior center-edge angle, acetabular inclination, center-to-trochanter distance) and clinical outcomes were measured with the modified Harris hip score (mHHS) as well as by prospectively recorded data on patient complications and followup.ResultsAcetabular labrochondral abnormalities included labral hypertrophy in all hips and labral and/or articular cartilage lesions requiring treatment in 13 hips. Radiographic analysis demonstrated consistent radiographic correction. The median preoperative mHHS improved from 64 to 92 at a median followup of 40 months (p < 0.001). Fourteen patients (14 hips) had a good or excellent clinical result. Two patients (two hips) were classified as failures based on mHHS less than 70 (n = 1) or conversion to total hip arthroplasty (n = 1).ConclusionsCombined surgical hip dislocation and PAO provides major deformity correction in Perthes-like hip deformities with associated acetabular dysplasia. Early clinical results suggest this technique is safe and effective. Long-term studies are needed to determine if improved long-term outcomes are associated with comprehensive deformity correction.

Level of Evidence

Level IV, therapeutic study.     

Crowe IV 型髋关节发育不良全髋关节置换术前计算机辅助设计

 目的 探索采用计算机辅助技术, 对接受全髋关节置换(total hip arthroplasty, THA)的 Crowe IV型髋关节发育不良患者进行术前评估, 确定髋臼大小、骨缺损程度, 并在此基础上辅助手术设 计、假体选择及骨缺损修复。 方法2011 年3 月至10 月, 共10 例(13 髋)Crowe IV型高位脱位髋关节发 育不良患者接受THA 治疗。患者均为女性;年龄32~74 岁, 平均42 岁。所有患者术前行髋关节三维CT 扫描, 然后将扫描数据输入SuperImage 软件重建骨盆及髋臼。重建后在不同角度精确评估真臼位置, 测 量真臼大小及前后柱厚度, 评估骨缺损程度;将髋臼试模、骨缺损修复材料(钽金属垫块)按1颐1 大小扫 描输入计算机系统, 进行术前模拟安放, 确定髋臼假体大小、安放位置;髋臼假体安放后评估遗留的骨缺 损, 确定骨缺损修复材料, 进行骨缺损修复模拟测试。 结果 9 例(12 髋)术中实际安放髋臼假体型号与 术前计算机辅助设计一致, 1 例(1髋)假体型号较术前设计大一号。所有患者髋臼安放位置与术前计划 一致, 均安放于真臼。髋臼骨缺损修复按术前设计:4 髋因髋臼顶部骨缺损明显(臼顶部骨性覆盖 < 70%), 采用钽金属垫块修复骨缺损, 以增强髋臼的稳定性;7 髋采用Harris 法自体股骨头植骨修复骨缺 损;2 髋髋臼杯植入后臼顶覆盖可, 术中未植骨。 结论 对Crowe IV型髋关节发育不良者行计算机辅助 下THA术前设计, 有助于术前精确评估真臼发育情况、大小及髋臼骨缺损, 提高手术治疗精确性。     

Periacetabular Osteotomy Restores the Typically Excessive Range of Motion in Dysplastic Hips With a Spherical Head

BackgroundResidual acetabular dysplasia is seen in combination with femoral pathomorphologies including an aspherical femoral head and valgus neck-shaft angle with high antetorsion. It is unclear how these femoral pathomorphologies affect range of motion (ROM) and impingement zones after periacetabular osteotomy.Questions/purposes(1) Does periacetabular osteotomy (PAO) restore the typically excessive ROM in dysplastic hips compared with normal hips; (2) how do impingement locations differ in dysplastic hips before and after PAO compared with normal hips; (3) does a concomitant cam-type morphology adversely affect internal rotation; and (4) does a concomitant varus-derotation intertrochanteric osteotomy (IO) affect external rotation?MethodsBetween January 1999 and March 2002, we performed 200 PAOs for dysplasia; of those, 27 hips (14%) met prespecified study inclusion criteria, including availability of a pre- and postoperative CT scan that included the hip and the distal femur. In general, we obtained those scans to evaluate the pre- and postoperative acetabular and femoral morphology, the degree of acetabular reorientation, and healing of the osteotomies. Three-dimensional surface models based on CT scans of 27 hips before and after PAO and 19 normal hips were created. Normal hips were obtained from a population of CT-based computer-assisted THAs using the contralateral hip after exclusion of symptomatic hips or hips with abnormal radiographic anatomy. Using validated and computerized methods, we then determined ROM (flexion/extension, internal- [IR]/external rotation [ER], adduction/abduction) and two motion patterns including the anterior (IR in flexion) and posterior (ER in extension) impingement tests. The computed impingement locations were assigned to anatomical locations of the pelvis and the femur. ROM was calculated separately for hips with (n = 13) and without (n = 14) a cam-type morphology and PAOs with (n = 9) and without (n = 18) a concomitant IO. A post hoc power analysis based on the primary research question with an alpha of 0.05 and a beta error of 0.20 revealed a minimal detectable difference of 4.6° of flexion.ResultsAfter PAO, flexion, IR, and adduction/abduction did not differ from the nondysplastic control hips with the numbers available (p ranging from 0.061 to 0.867). Extension was decreased (19° ± 15°; range, −18° to 30° versus 28° ± 3°; range, 19°–30°; p = 0.017) and ER in 0° flexion was increased (25° ± 18°; range, −10° to 41° versus 38° ± 7°; range, 17°–41°; p = 0.002). Dysplastic hips had a higher prevalence of extraarticular impingement at the anteroinferior iliac spine compared with normal hips (48% [13 of 27 hips] versus 5% [one of 19 hips], p = 0.002). A PAO increased the prevalence of impingement for the femoral head from 30% (eight of 27 hips) preoperatively to 59% (16 of 27 hips) postoperatively (p = 0.027). IR in flexion was decreased in hips with a cam-type deformity compared with those with a spherical femoral head (p values from 0.002 to 0.047 for 95°–120° of flexion). A concomitant IO led to a normalization of ER in extension (eg, 37° ± 7° [range, 21°–41°] of ER in 0° of flexion in hips with concomitant IO compared with 38° ± 7° [range, 17°–41°] in nondysplastic control hips; p = 0.777).ConclusionsUsing computer simulation of hip ROM, we could show that the PAO has the potential to restore the typically excessive ROM in dysplastic hips. However, a PAO can increase the prevalence of secondary intraarticular impingement of the aspherical femoral head and extraarticular impingement of the anteroinferior iliac spines in flexion and internal rotation. A cam-type morphology can result in anterior impingement with restriction of IR. Additionally, a valgus hip with high antetorsion can result in posterior impingement with decreased ER in extension, which can be normalized with a varus derotation IO of the femur. However, indication of an additional IO needs to be weighed against its inherent morbidity and possible complications. The results are based on a limited number of hips with a pre- and postoperative CT scan after PAO. Future prospective studies are needed to verify the current results based on computer simulation and to test their clinical importance.

Level of Evidence

Level III, therapeutic study.     

Periacetabular Osteotomy Provides Higher Survivorship Than Rim Trimming for Acetabular Retroversion

Background

Acetabular retroversion can cause impaction-type femoroacetabular impingement leading to hip pain and osteoarthritis. It can be treated by anteverting periacetabular osteotomy (PAO) or acetabular rim trimming with refixation of the labrum. There is increasing evidence that acetabular retroversion is a rotational abnormality of the entire hemipelvis and not a focal overgrowth of the anterior acetabular wall, which favors an anteverting PAO. However, it is unknown if this larger procedure would be beneficial in terms of survivorship and Merle d’Aubigné scores in a midterm followup compared with rim trimming.

Questions/purposes

We asked if anteverting PAO results in increased survivorship of the hip compared with rim trimming through a surgical hip dislocation in patients with symptomatic acetabular retroversion.

Methods

We performed a retrospective, comparative study evaluating the midterm survivorship of two matched patient groups with symptomatic acetabular retroversion undergoing either anteverting PAO or acetabular rim trimming through a surgical hip dislocation. Acetabular retroversion was defined by a concomitantly present positive crossover, posterior wall, and ischial spine sign. A total of 279 hips underwent a surgical intervention for acetabular retroversion at our center between 1997 and 2012 (166 periacetabular osteotomies, 113 rim trimmings through surgical hip dislocation). A total of 99 patients (60%) were excluded from the PAO group and 56 patients (50%) from the rim trimming group because they had any of several prespecified conditions (eg, dysplasia or pediatric conditions 61 [37%] for the PAO group and two [2%] for the rim trimming group), matching (10 [6%]/10 [9%] hips), deficient records (10 [6%]/13 [12%] hips), or the patient declined or was lost to followup (18 [11%]/31 [27%] hips). This left 67 hips (57 patients) that underwent anteverting PAO and 57 hips (52 patients) that had acetabular rim trimming. The two groups did not differ in terms of age, sex, body mass index, preoperative ROM, preoperative Merle d’Aubigné-Postel score, radiographic morphology of the acetabulum (except total and anterior acetabular coverage), alpha angle, Tönnis grade of osteoarthritis, and labral and chondral lesions on the preoperative MRI. During the period in question, we generally performed PAO from 1997 to 2003. With the availability of surgical hip dislocation and labral refixation, we generally performed rim trimming from 2004 to 2010. With growing knowledge of the underlying pathomorphology, anteverting PAOs became more common again around 2007 to 2008. A minimum followup of 2 years was required for this study. Failures were included at any time. The median followup for the anteverting PAO group was 9.5 years (range, 2–17.4 years) and 6.8 years (range, 2.2–10.5 years) for the rim trimming group (p < 0.001). Kaplan-Meier survivorship analysis was performed using the following endpoints at 5 and 10 years: THA, radiographic progression of osteoarthritis by one Tönnis grade, and/or Merle d’Aubigné-Postel score < 15 points.

Results

Although the 5-year survivorship of the two groups was not different with the numbers available (86% [95% confidence interval {CI}, 76%–94%] for anteverting PAO versus 86% [95% CI, 76%–96%] for acetabular rim trimming), we found increased survivorship at 10 years in hips undergoing anteverting PAO for acetabular retroversion (79% [95% CI, 68%–90%]) compared with acetabular rim trimming (23% [95% CI, 6%–40%]) at 10 years (p < 0.001). The drop in the survivorship curve for the acetabular rim trimming through surgical hip dislocation group started at Year 6. The main reason for failure was a decreased Merle d’Aubigné score.

Conclusions

Anteverting PAO may be the more appropriate treatment for hips with substantial acetabular retroversion. This may be the result of reduction of an already smaller lunate surface of hips with acetabular retroversion through rim trimming. However, rim trimming may still benefit hips with acetabular retroversion in which only one or two of the three signs are positive. Future randomized studies should compare these treatments.

Level of Evidence

Level III, therapeutic study.

     

Total Hip Arthroplasty for Crowe Type IV Hip Dysplasia: Surgical Techniques and Postoperative Complications

Total hip arthroplasty (THA) of Crowe type IV developmental dysplasia of the hip (DDH) is challenging. Although traditional (lateral, posterolateral, and posterior) THA approaches have been used with great anatomic success, they damage periarticular muscles, which are already quite weak in type IV DDH. The recently developed direct anterior approach (DAA) can provide an inter‐nerve and inter‐muscle approach for THA of type IV dysplasia hips. However, femur exposure with the DAA could be difficult during surgery and it is hard to apply femoral shortening osteotomy. THA techniques used for type IV DDH include anatomic hip center techniques (true acetabular reconstruction) and high hip center techniques, wherein an acetabulum is reconstructed above the original one. Although anatomic construction of the hip center is considered “the gold standard” treatment, it is impossible if the anatomical acetabular is too small and shallow. Procedures used to support type IV DDH reduction with anatomic hip center techniques include greater trochanter osteotomy, lesser trochanter osteotomy, and subtrochanteric osteotomy. However, these techniques have yet to be standardized, and it is unclear which is best for type IV DDH. One‐state and two‐state non‐osteotomy reduction techniques have also been introduced to treat type IV DDH. Potential complications of THA performed in patients with type IV DDH include leg length discrepancy (LLD), peri‐operative femur fracture, nonunion of the osteotomy site, and nerve injury. It is worth noting that nowadays an increasing number of Crowe type IV DDH patients are more sensitive to postoperative LLD.     

Acetabular morphological variation in Asian patients with femoral neck fracture: A three-dimensional CT-based study

AimsThe acetabular morphology varies greatly among individuals, and hypoplasia is more common in Asia than in Europe. Dislocation after bipolar hip arthroplasty (BHA) for femoral neck fracture occurs at a constant rate, and is affected by the acetabular morphology. This study aimed to clarify individual differences in the acetabula of Asian patients with displaced femoral neck fractures.Patients and methodsFifty patients with displaced femoral neck fractures were assessed (50 fractured hips, 50 non-fractured hips). On CT corrected by the anterior pelvic plane, the 100 hips were assessed regarding acetabular coverage (six parameters), acetabular depth (two parameters), and acetabular opening angle (four parameters). Additional parameters related to the fracture and sex were examined. The percentile of each parameter was shown for all hips.ResultsThere was no patient with hip dysplasia defined as superior acetabular sector angle (SASA) less than 110° Compared with men, women had a significantly smaller anterior acetabular sector angle (AASA) (p = 0.016), and significantly larger acetabular inclination angle (p = 0.006) and acetabular index angle (p = 0.034). In the group with a normal SASA, seven hips (7.3%) had an anterior wall defect (AASA<50°) and five hips (5.2%) had a posterior wall defect (posterior acetabular sector angle<90°).ConclusionOlder adults with femoral neck fractures can have anterior wall and posterior wall defects, even if their SASA is normal. Hidden acetabular dysplasia may be related to post-BHA dislocation. So, our results suggest that is important to accurately evaluate the acetabulum of patients with femoral neck fracture before surgery.     

Application of three-dimensional computerised tomography reconstruction and image processing technology in individual operation design of developmental dysplasia of the hip patients

Purpose

Acetabular coverage deficiency displays individual difference among patients with developmental dysplasia of the hip (DDH). Therefore, the correct direction and degree of the acetabular fragment is patient-specific during Bernese periacetabular osteotomy (PAO). This paper introduces a feasible method using 3D computed tomography (CT) and computer image processing technology for customised surgical planning.

Methods

CT data of 96 hips in 60 DDH patients (male 15, female 45; average age/range 30?±?8/14–49 years) and 53 normal hips (male 13, female 37; average age/range 52?±?13/16–69 years) were reconstructed using commercially available software Mimics and Imageware. Geometric parameters of each hip were measured in relation to the anterior pelvic plane after correcting for pelvic tilt and rotation. Deficiency types and degrees of acetabular dysplasia in patients with DDH were determined by comparison with normal hips, and improvement in femoral-head coverage was analysed again after virtual PAO. A customised surgery programme for each DDH patient was designed and provided the reference for the actual operation.

Results

We produced a 3D pelvic model using image processing software, doing precise measurement and with close approximation to the actual PAO. Lateral centre-edge angle (LCEA), anterior centre-edge angle (ACEA), acetabular anteversion angle (AAVA), anterior acetabular sector angle (AASA) and posterior acetabular sector angle (PASA) of normal hips in the control group were 35.128?±?6.337, 57.052?±?6.853, 19.215?±?5.504, 61.537?±?7.291 and 99.434?±?8.372°, respectively. Angles of hips with DDH before surgery were 11.46?±?11.19, 35.79?±?13.75, 22.77?±?6.13, 43.58?±?9.15 and 88.46?±?8.24, which were corrected to 33.81?±?2.36, 55.38?±?2.09, 20.16?±?2.18, 58.29?±?7.60, and 4.71?±?7.75°, respectively, after surgery. After virtual Bernese PAO, LCEA, ACEA, AAVA, AASA and PASA were corrected significantly (p?<?0.01). There was no statistically significant differences between LCEA, ACEA and AAVA after virtual Bernese PAO and normal hips (p?=?0.06, p?=?0.23, p?=?0.06°, respectively). AASA improved significantly (p?=?0.002) post-operatively at the cost of reducing posterior coverage represented by PASA, which is significantly smaller than in normal and pre-operative hips of DDH patients (p?<?0.01).

Conclusions

The geometric feature of the pelvis for patients with DDH can be assessed comprehensively by using 3D-CT reconstruction and image processing technology. Based on this method, surgeons can design individualised treatment scheme and improve the effect of PAO.

     

Objective Activity Levels and Patient-Reported Outcomes After Total Hip Arthroplasty and Periacetabular Osteotomy: Retrospective Matched Cohort Study at Mean 12-Year Follow-Up

BackgroundThere is increasing interest in improving activity after total hip arthroplasty (THA) and periacetabular osteotomy (PAO). The present study evaluated whether there were differences in the subjective and objective activity levels of THA and PAO patients at mean 12-year follow-up (range 4-20) and what factors influence the objective activity levels.MethodsTHA and PAO patients (30 patients each; mean age: 66 and 63 years, respectively), who had undergone surgery for osteoarthritis due to acetabular dysplasia, were included. Patients were retrospectively matched based on age, gender, body mass index, follow-up duration, and preoperative University of California, Los Angeles activity score (UCLA score). Patients were surveyed for the subjective activity levels using the Oxford Hip Score and UCLA score. Objective activity levels (the number of steps, upright time, and the number of sit-to-stand transitions) were made using an accelerometer.ResultsThere was no significant difference in subjective activity level between THA and PAO patients. The number of steps was significantly higher in PAO than in THA patients. Multivariable analyses revealed that THA and low Oxford Hip Score activities of daily living were negatively associated with the number of steps, that men and high UCLA score were negatively associated with upright time, and that high body mass index was negatively associated with sit-to-stand transitions in THA and PAO patients.ConclusionThis study suggested that although there was no difference in postoperative subjective activity level between THA and PAO patients, there was a difference in objective activity level. Providing guidance to these patients based on objective activity may lead to higher activity levels.     

双侧分别行髋臼周围截骨和全髋关节置换术后的功能比较

目的探讨双侧分别接受髋臼周围截骨术(PAO)和全髋关节置换术(THA)的发育性髋关节发育不良(DDH)患者术后自评关节功能的差异及对手术倾向的影响。 方法回顾性分析解放军总医院第四医学中心关节外科2010年6月至2017年5月双侧髋关节一侧行PAO治疗对侧行THA治疗的患者,纳入标准为术前诊断为双侧DDH,且同一名患者双侧髋关节术前DDH分型相同,患者仅接受单纯PAO手术和THA手术。采用方差分析比较手术时间,术中出血量和围手术期并发症等手术相关数据,采用独立样本t检验比较术后早期和1年后随访视觉疼痛评分、髋关节Harris功能评分、患者自我功能评分(简化国际髋关节评分问卷量表)和手术倾向性。 结果共有12例患者(24髋)纳入研究,其中男性2例,女性10例,首次手术平均年龄为(35±4)岁,两次手术间隔(17±11)月。术后3个月THA侧Harris髋关节评分明显改善(t＝－15.222,P<0.001),PAO侧则较术前下降(t＝3.927,P＝0.001),至术后1年随访双侧髋关节Harris评分差异无统计学意义(t＝1.156,P>0.05),患者自我功能评价差异有统计学意义(t＝3.550,P＝0.002)。PAO术后患者关节疼痛持续时间较长,使用拐杖非负重活动时间较THA长。PAO侧髋关节共出现3例并发症,THA侧出现1例。早期随访THA侧满意度(58.3%)高于PAO侧(41.7%),但差异无统计学意义(χ²＝0.667,P>0.05);至末次随访患者对两种术式的满意度相同。手术倾向性方面,所有患者在末次随访时倾向接受PAO手术。 结论PAO和THA在功能改善和疼痛缓解方面均可获得满意的疗效,术后1年以上随访患者更倾向接受PAO。此研究结果对年轻症状型DDH患者的治疗方案选择有一定的参考意义。     

Spinopelvic alignment does not change after bilateral total hip arthroplasty in patients with bilateral Crowe type-IV developmental dysplasia of the hip

ObjectiveThis prospective study aimed to evaluate the changes in the sagittal alignment after total hip arthroplasty (THA) in patients with hip osteoarthritis (OA) secondary to Crowe type-IV developmental dysplasia of the hip (DDH) and whether THA would contribute to the relief of low-back pain (LBP).MethodsA total of 27 patients (2 men and 25 women) with bilateral hip OA secondary to Crowe type-IV DDH were enrolled in this study. Their mean age at the time of surgery was 40,36±12,35. All patients underwent simultaneous, bilateral THA between January 2015 and December 2016. Clinical assessment included Oswestry disability index (ODI) score and Harris hip score (HHS), and pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL), and pelvic tilt (PT) were measured from radiographs.ResultsPreoperatively, all the patients had hip and low-back pain. Preoperative and final follow-up ODI scores were 48.3 and 3.9 (p=0.000), respectively. HHS changed from 43.54 to 92.68 (p=0.000). PT and PI significantly changed from −20.4°±20.4° to 3.2°±16.7° (p=0.001) and from 26.6°±35.1° to 47.4°±17.9° (p=0.001), respectively. There were no significant differences regarding the SS and LL measurements. Age or limb-length discrepancy was not significantly associated with the spinopelvic alignment measurements.ConclusionRestoring the function of the hip with THA is shown to improve hip-associated LBP, but the accompanying hyperlordosis does not change. THA in patients with bilateral Crowe type-IV hips relieves hip pain as well as associated LBP. Hyperlordosis of the lumbar vertebra does not change after surgery, but PI and PT changes are observed; this improvement might have a role in the relief of LBP.Level of EvidenceLevel IV, Therapeutic study     

Are There Sex-dependent Differences in Acetabular Dysplasia Characteristics?

BackgroundMany patients who undergo periacetabular osteotomy (PAO) for symptomatic acetabular dysplasia experience decreased pain and improved function, yet some experience inadequate clinical improvement. The etiologies of treatment failure have not been completely defined, and sex-dependent disease characteristics that may be associated with less pain relief are not understood.Question/purposesWe sought to determine whether there were clinically important sex-specific differences between male and female patients undergoing PAO for acetabular dysplasia in terms of (1) clinical parameters (anthropomorphic traits and hip scores), (2) radiographic findings, and (3) intraoperative findings at the time of PAO, in particular findings potentially associated with femoroacetabular impingement (FAI) such as chondromalacia at the head-neck junction, impingement trough, or reduced head-neck offset.MethodsBetween 2007 and 2012 we treated 245 patients (270 hips) with a PAO for symptomatic acetabular dysplasia. Of those, 16 patients (16 hips; 6%) had insufficient documentation for review in the medical record and another 49 patients (51 hips; 19%) met prespecified exclusion criteria, leaving 180 patients (203 hips; 75%) for analysis in this retrospective study. One hundred thirty-nine patients were females and 41 were males. Clinical data including patient demographics, physical examination, patient self-reported outcome scores, radiographic morphologic features, and intraoperative findings were collected prospectively as part of an institutional registry. Statistical analysis was performed with univariate and multivariate analyses.ResultsMean age was similar among sexes; however, BMI was greater in males compared with females (26 versus 24 kg/m²; p = 0.002). Males had less hip ROM including internal rotation at 90° flexion (14° ± 13.8° versus 25° ± 16.2°; p = 0.001). Males had higher preoperative UCLA (7 ± 2, versus 6 ± 2; p = 0.02) and Harris hip scores (63 ± 15 versus 58 ± 16; p = 0.04). Radiographically, a crossover sign (88% versus 39%; p < 0.001) and posterior wall sign (92% versus 63%; p < 0.001) were more common in males. Males had greater alpha angles on the frog lateral (63° ± 15.3° versus 58° ± 16°; p = 0.04) and Dunn radiograph views (64° ± 15.5° versus 56° ± 14.8°; p = 0.02). The incidence of femoral head-neck chondromalacia (62% versus 82%; p = 0.03) and an impingement trough observed at surgery was greater in males (35% versus 17%; p = 0.01). Multivariate analysis showed differences between the sexes for reduced internal rotation in flexion, a higher Dunn alpha angle, increased incidence of a crossover sign, and a lower anterior center-edge angle.ConclusionsThere are sex-dependent, disease characteristic differences in patients with symptomatic acetabular dysplasia. Most notably, male patients have a greater prevalence of clinical, radiographic, and intraarticular findings consistent with concurrent FAI and instability and potentially a heightened risk of secondary FAI after PAO, however postoperative and long-term followup are needed to confirm these findings and it remains unclear which patients need surgical correction of the impingement and instability. Preoperative evaluation of acetabular dysplasia in males should at least include careful attention to factors associated with symptomatic FAI; however, further studies are needed to determine when surgical correction is needed.

Level of Evidence

Level III, therapeutic study.     

Is Robotic-Assisted Technology Still Accurate in Total Hip Arthroplasty for Fibrous-Fused Hips?

BackgroundTotal hip arthroplasty (THA) for fibrous-fused hips is technically demanding. This study aimed to evaluate the precision and accuracy, as well as the rate of conversion of robotic-assisted THA in such difficult patients.MethodsWe retrospectively analyzed 67 patients (84 hips) who underwent THA with fibrous-fused hips between August 2018 and June 2021 at our institution. Demographics, acetabular cup positioning, leg-length discrepancies, and postoperative Harris hip scores were recorded for all patients. Thirty-six patients (44 hips) who underwent robotic-assisted THA and 31 patients (40 hips) who underwent manual THA were enrolled in this study.ResultsThe robot accurately executed the preoperative plan, and there were no statistically significant differences between the preoperative planned anteversion, inclination, and postoperative measurements. In the robotic group, the percentage of acetabular cups in the safe zone was significantly higher than in the manual group (87.2 versus 55%, respectively, P = .042). The rate of conversion to manual THA for various reasons in the robotic-assisted THA group was 11.4% (5/44). Compared with manual THA, the mean increase in operative time for conversion from robotic-assisted to manual THA was 24 min (P < .001).ConclusionIn patients who have fibrous-fused hips, preoperative planning can be accurately executed by robotic-assisted technology. Compared with manual THA, robotic-assisted THA had a remarkable advantage in improving the frequency of achieving cup positioning within the target zone. Overall, robotic-assisted technology was helpful in such difficult cases, and the approximately 11.4% of cases converted to manual THA are reminders that surgeons should be thoroughly prepared preoperatively.     

Acetabular and Femoral Component Positioning Using Direct Anterior Approach Versus Posterior Approach in Total Hip Arthroplasty

PurposeDirect anterior approach (DAA) has recently become popular in total hip arthroplasty (THA). However, irrespective of the surgical approach used, component malposition is an important factor affecting function and complications after THA. This study aims to compare component positioning on the femoral and acetabular side between DAA and posterior approach (PA) to the hip joint. We hypothesized that the two approaches are similar in terms of component positioning.MethodsWe prospectively studied 50 patients, matched according to age, sex, and body mass index, undergoing THA, divided non-randomly into 2 groups. Group 1 comprised 25 patients (35 hips) undergoing THA using DAA and group 2 comprised 25 patients (25 hips) undergoing THA using PA. Ten patients from group 1 had simultaneous bilateral THA. Radiological parameters studied were acetabular inclination (AI), coronal femoral stem alignment (CFA), leg length difference (LLD), acetabular cup version (AV), and femoral stem version (FV).ResultsThere was no significant difference in AI, CFA, LLD, AV, and FV between the two groups. Excellent to good inter and intra-observer reliability expressed in terms of intraclass correlation coefficient (ICC) was noted for all the radiographic measurements.ConclusionBoth DAA and PA for THA achieve comparable radiological component positioning. DAA may not provide any advantage over PA in terms of positioning of the prosthesis.Level of EvidenceLevel II, non-randomized comparative study.