Total hip arthroplasty in developmental dysplasia of the hip: Review of anatomy, techniques and outcomes

Incidence, Prevalence, Risk Factors, and Clinical Treatment for Children with Developmental Dysplasia of the Hip in Saudi Arabia. A Systematic Review

BACKGROUND

Developmental dysplasia of the hip (DDH) leads to pain, joint instability, and early degenerative joint disease. Incidence, prevalence, and management strategies of DDH have been well-documented in several countries, but not in Saudi Arabia.

OBJECTIVE

We synthesized the current evidence regarding incidence, prevalence, risk factors, and clinical treatment for children with DDH in Saudi Arabia.

METHODS

We searched 3 databases to locate studies. Studies that included children with DDH in Saudi Arabia; reported either incidence rate, prevalence, risk factors, and/or clinical practice; and were available in English or Arabic were included. We excluded reviews, case studies, or animal studies. Two independent authors reviewed potential studies and assessed study's quality.

RESULTS

Our search yielded 67 potential studies, of which 16 studies were included (total DDH sample = 3,127; age range = 2.5 to 86.4 months). Three studies reported incidence rates ranging from 3.1 to 4.9 per 1000 births, and 3 studies reported prevalence ranging from 6 to 78%. Nine studies reported that female sex, breech position, family history, and age less than 3 years were risk factors associated with DDH. Four studies reported that brace applications and closed reduction were conservative treatments, and 9 studies reported that open hip reduction, adductor tenotomy, and/or pelvic osteotomy were surgical approaches to treat DDH.

CONCLUSIONS

In Saudi Arabia, the Incidence and prevalence rates of DDH are 3.1 to 4.9 per 1,000 births, and 6-78%, respectively (differ from what has been reported in other countries), but the risk factors of DDH in Saudi Arabia appear to be similar in comparison to other countries (female, breech presentation, family history of DDH).

Total hip arthroplasty with porous tantalum trabecular metal pads in patients with Crowe IV developmental dysplasia of the hip: a midterm followup study

PURPOSE

Crowe IV developmental dysplasia of the hip (DDH) is a catastrophic hip disease. Moreover, obtaining ideal clinical efficacy in conventional total hip arthroplasty (THA) is often difficult. In this study, we aimed to assess the mid-term clinical results of THA with porous tantalum trabecular metal (TM) pads for acetabular reconstruction in the treatment of Crowe IV DDH.

METHODS

A cohort of 28 patients (32 hips) diagnosed with Crowe type IV DDH who underwent acetabular reconstruction during THA using TM pads with scheduled follow-up between 2011 and 2018, were included in this study. Eight cases were men and 24 were women, with a mean age of 48.4 years (range, 36-72 years) and a mean follow-up was 74.3 months (range, 42-132 months). All patients underwent acetabular reconstruction using TM pads and total hip replacement with subtrochanteric osteotomy.

RESULTS

At the final follow-up, 28 hips (87.5%) demonstrated mild or no postoperative limping. The Harris Hip Score improved from 58.4 ± 10.6 preoperatively to 85.6 ± 8.9. The mean pain, stiffness, and function scores on the Western Ontario and McMaster University Osteoarthritis index were 86.5 ± 10.2, 87.3 ± 12.4 and 85.4 ± 11.6 respectively. The mean score of patient satisfaction was 90.4 ± 7.6. Additionally, the SF-12 physical summary score was 41.8 ± 5.6 and the SF-12 mental summary score was 51.6 ± 5.4. TM construct survivorship due to all-cause failure was 90.6% at 5 years with 3 hips at risk, 87.5% at 10 years with 4 hips at risk. The survivorship due to failure from aseptic loosening was 96.9% at 5 years with 1hips at risk and 93.75% at 10 years with 2 hips at risk.

CONCLUSION

This study demonstrated satisfactory mid-term clinical and radiological results with the application of TM pads for acetabular reconstruction combined with THA in patients with Crowe IV DDH.

TRIAL REGISTRATION NUMBER

ChiCTR1800014526, Date: 18/01/2018.

Direct Anterior Approach in Total Hip Arthroplasty for Severe Crowe IV Dysplasia: Retrospective Clinical and Radiological Study

Background and Objectives: total hip arthroplasty (THA) for Crowe IV hip dysplasia poses challenges due to severe leg shortening, muscle retraction and bone stock issues, leading to an increased neurological complication, and revision rate. The direct anterior approach (DAA) is used for minimally invasive THA but its role in Crowe IV dysplasia is unclear. This retrospective study examines if DAA effectively restores hip biomechanics in Crowe IV dysplasia patients with <4 cm leg length discrepancy, managing soft tissue and yielding functional improvement, limb length correction, and limited complications. Materials and Methods: 19 patients with unilateral Crowe IV hip osteoarthritis and <4 cm leg length discrepancy undergoing DAA THA were reviewed. Surgery involved gradual soft tissue release, precise acetabular cup positioning, and stem placement without femoral osteotomy. Results: results were evaluated clinically and radiographically, with complications recorded. Follow-up revealed significant Harris Hip Score and limb length discrepancy improvements. Abductor muscle insufficiency was present in 21%. The acetabular component was accurately placed, centralizing the prosthetic joint's rotation. Complications occurred in 16% of cases, including fractures, nerve issues, and infection. DAA in THA showcased positive outcomes for hip function, limb length, and biomechanics in Crowe IV dysplasia. Conclusions: the technique enabled accurate cup positioning and rotation center adjustment. Complications were managed well without implant revisions. DAA is a viable option for Crowe IV dysplasia, restoring hip function, biomechanics, and reducing limb length discrepancy. Larger, longer studies are needed for validation.

Risk Factors for Dislocation following Total Hip Arthroplasty in Developmental Dysplasia of the Hip: A Systematic Review and Meta-Analysis

PURPOSE

This systematic review and meta-analysis aimed to identify risk factors of dislocation after total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH).

METHODS

A systematic literature review was performed on 18th August 2022 using Medline, Embase, Scopus, Web of Science electronic databases, and a manual search. The study was conducted according to the PRISMA guidelines and registered with PROSPERO. Statistical analysis includes assessment of heterogeneity and data synthesis using RevMan 5.4.

RESULTS

Review of five studies including 2865 patients and 116 dislocated hips found that lower body mass index (BMI) (SMD = 0.22, p = 0.04, I2 = 0%), Crowe classification type IV versus I, II, and III (OR = 2.70, p = 0.004, I2 = 51%), higher cup inclination (SMD = 0.39 p = 0.0007, I2 = 0%), femoral head size < 28 mm (OR = 5.07, p = 0.003, I2 = 71%), lateral surgical approach (OR = 1.96, p = 0.02, I2 = 0%), and postoperative infection (OR = 6.26, p < 0.0001, I2 = 0%) were significant risk factors. However, age, gender, cup anteversion, femoral osteotomy, vertical (V-COR) centre of rotation, intraoperative fracture, preoperative and postoperative leg length discrepancy (LLD) and previous hip surgery were not found to be significant risk factors.

CONCLUSION

This study underscores importance of these risk factors in THA planning for DDH patients to reduce dislocation risk. Further research needed to understand mechanisms.

Assessing Leg Length Discrepancy Is Necessary Before Arthroplasty in Patients With Unilateral Crowe Type IV Hip Dislocation

BACKGROUND

THA for high-riding developmental dysplasia of the hip (DDH) is challenging in terms of length equalization. Although previous studies suggested preoperative templating on AP pelvic radiographs is insufficient in patients with unilateral high-riding DDH because of hypoplasia of the hemipelvis on the affected side and unequal femoral and tibial length on scanograms, the results were controversial. The EOS™ (EOS™ Imaging) is a biplane X-ray imaging system using slot-scanning technology. Length and alignment measurements have been shown to be accurate. We used the EOS to compare the lower limb length and alignment in patients with unilateral high-riding DDH.

QUESTIONS/PURPOSES

(1) Is there an overall leg length difference in patients with unilateral Crowe Type IV hip dysplasia? (2) In patients with unilateral Crowe Type IV hip dysplasia with an overall leg length difference, is there a consistent pattern of abnormalities in the femur or tibia that account for observed differences? (3) What is the impact of unilateral high-riding Crowe Type IV dysplasia on femoral neck offset and knee coronal alignment?

METHODS

Between March 2018 and April 2021, we treated 61 patients with THA for Crowe Type IV DDH (high-riding dislocation). EOS imaging was performed preoperatively in all patients. Eighteen percent (11 of 61) of the patients were excluded because of involvement of the opposite hip, 3% (two of 61) were excluded for neuromuscular involvement, and 13% (eight of 61) had previous surgery or fracture, leaving 40 patients for analysis in this prospective, cross-sectional study. Each patient's demographic, clinical, and radiographic information was collected with a checklist using charts, Picture Archiving and Communication System, and an EOS database. EOS-related measurements that were related to the proximal femur, limb length, and knee-related angles were recorded for both sides by two examiners. The findings of the two sides were statistically compared.

RESULTS

The overall limb length was not different between the dislocated and nondislocated sides (mean 725 ± 40 mm versus 722 ± 45 mm, mean difference 3 mm [95% CI -3 to 9 mm); p = 0.08). Apparent leg length was shorter on the dislocated side (mean 742 ± 44 mm versus 767 ± 52 mm, mean difference -25 mm [95% CI -32 to 3 mm]; p < 0.001). We observed that a longer tibia on the dislocated side was the only consistent pattern (mean 338 ± 19 mm versus 335 ± 20 mm, mean difference 4 [95% CI 2 to 6 mm]; p = 0.002), but there was no difference between the femur length (mean 346 ± 21 mm versus 343 ± 19 mm, mean difference 3 mm [95% CI -1 to 7]; p = 0.10). The femur of the dislocated side was longer by greater than 5 mm in 40% (16 of 40) of patients and shorter in 20% (eight of 40). The mean femoral neck offset of the involved side was shorter than that of the normal side (mean 28 ± 8 mm versus 39 ± 8 mm, mean difference -11 mm [95% CI -14 to -8 mm]; p < 0.001). There was a higher valgus alignment of the knee on the dislocated side with a decreased lateral distal femoral angle (mean 84° ± 3° versus 89° ± 3°, mean difference - 5° [95% CI -6° to -4°]; p < 0.001) and increased medial proximal tibia angle (mean 89° ± 3° versus 87° ± 3°, mean difference 1° [95% CI 0° to 2°]; p = 0.04).

CONCLUSION

A consistent pattern of anatomic alteration on the contralateral side does not exist in Crowe Type IV hips except for the length of the tibia. All parameters of the limb length could be shorter, equal to, or longer on the dislocated side. Given this unpredictability, AP pelvis radiographs are not sufficient for preoperative planning, and individualized preoperative planning using full-length images of the lower limbs should be performed before arthroplasty in Crowe Type IV hips.

LEVEL OF EVIDENCE

Level I, prognostic study.

Staged Bilateral Total Hip Arthroplasty in a Patient With Larsen Syndrome

Larsen syndrome is a rare genetic disorder characterized by weak connective tissues and various musculoskeletal abnormalities. This is a case report of a 39-year-old patient with Larsen syndrome who presented with over a decade of bilateral hip pain and difficulty ambulating. This patient has a prior history of bilateral congenital hip dislocations that were treated with open reduction and spica casting as a child with good result. Years later, she went on to develop bilateral hip osteoarthritis with significant remodeling of the proximal femur. The goal of this case presentation is to demonstrate the utility of total hip arthroplasty for this patient and discuss surgical challenges and considerations.

Patient-Reported Outcomes and Factors Impacting Success of the Periacetabular Osteotomy

Hip dysplasia is a condition affecting both infants and adults, characterized by a shallow acetabulum that does not sufficiently cover the head of the femur. This leads to instability of the hip and elevated levels of mechanical stress around the acetabular rim. A popular procedure for the correction of hip dysplasia is the periacetabular osteotomy (PAO), in which fluoroscopically guided osteotomies around the pelvis are made to allow for repositioning of the acetabulum to fit properly on the femoral head. This systematic review aims to analyze patient factors that impact outcomes, as well as patient-reported outcomes such as the Harris Hip Score (HHS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC). The patients in this review did not undergo any prior intervention for acetabular hip dysplasia, allowing for an unbiased reporting of outcomes from all included studies. Of studies reporting HHS, the mean preoperative HHS was 68.92 and the mean postoperative HHS was 89.1. Of the study that reported mHHS, the mean preoperative mHHS was 70, and the mean postoperative mHHS was 91. Of the studies reporting WOMAC, the mean preoperative WOMAC was 66, and the mean postoperative WOMAC was 63. Key findings of this review are that of the seven included studies, six achieved a minimally important clinical difference (MCID) based on patient-reported outcomes, and factors impacting outcome are preoperative Tönnis osteoarthritis (OA) grade, pre and postoperative lateral-center edge angle (LCEA), preoperative hip joint congruency, postoperative Tönnis angle, and age. In patients with no prior intervention for hip dysplasia, the PAO is a successful procedure with significant improvement in postoperative patient-reported outcomes. Despite the reported success of the PAO, proper patient selection is vital to avoid early conversions to total hip arthroplasty (THA) and prolonged pain. However, further investigation is prompted regarding the long-term survivorship of the PAO in patients with no prior intervention for hip dysplasia.

Femoral Head Autograft to Manage Acetabular Bone Loss Defects in THA for Crowe III Hips by DAA: Retrospective Study and Surgical Technique

Introduction: The pathologic anatomy of Crowe III is characterized by the erosion of the superior rim of acetabulum, with a typical bone defect in its supero-lateral portion. The performance of a total hip arthroplasty requires the management of the acetabular bone defect, and femoral head autograft can be a valid option to optimize implant coverage. Material and Methods: In all, eight Crowe III patients (nine hips), seven of which having unilateral hip affected, and one with bilateral involvement by secondary osteoarthritis in DDH; maximum limb length discrepancy (LLD) of 3.5 cm in unilateral patients. All were operated on by direct anterior approach. Patients were evaluated in terms of clinical, surgical, and radiological (center-edge, horizontal coverage, cup inclination) parameters. Results: Cup placement was implanted with a mean of 39.5 ± 7.5°. Stem alignment showed average 1.5 ± 2.3° in valgus. LLD showed an overall average preoperative of -29.5 ± 10.5 mm at the affected side, with a significant improvement to -2.5 ± 6.4 mm (p = 0.023). The mean initial coverage evaluated like a percentage of the horizontal bone host was 52.1 ± 7.1%, while the mean final coverage at the last post-operative X-ray from femoral autograft bone was 97.0 ± 4.5% with an average improvement of 44.5%. Average CE improved from -9.5 ± 5.2° (CE I) to the immediate post-operative (CE II) of 40.6 ± 8.2°. At the final follow up, CE III showed a mean of 38.6 ± 6.2°, with an average decrease of 2.0°. Discussion: Acetabular bone defect in Crowe III DDH patients undergoing THA by DAA, can be efficiently managed by massive autograft femoral head, which allowed an adequate and long-lasting coverage of the implant, with cup positioning at the native acetabulum.

Acetabular reconstruction with femoral head autograft in primary total hip arthroplasty through a direct anterior approach is a reliable option for patients with secondary osteoarthritis due to developmental dysplasia of the hip

BACKGROUND

Developmental dysplasia is challenging to treat with total hip arthroplasty via the direct anterior approach (DAA). Reconstructing the former anatomy while restoring the acetabular bone stock for future revisions in this young patient collective combined with the known advantages of the DAA would be desirable. The purpose of this study was to analyze the feasibility, radiographic outcome and clinical outcome of primary uncemented total hip arthroplasty with bulk femoral head autograft for acetabular augmentation through a DAA with a minimal follow-up of 12 months.

METHODS

A retrospective, consecutive series from March 2006 to March 2018 of 29 primary total hip arthroplasty with acetabular augmentation with bulk femoral head autograft through a direct anterior approach was identified. All complications, reoperations and failures were analyzed. Radiographic and clinical outcome was measured.

RESULTS

24 patients (29 hips) with a mean age of 43 (18-75) years and a mean follow-up of 35 months (12-137) were included. Surgical indication was secondary osteoarthritis for developmental dysplasia of the hip (Hartofilakidis Grade A (n = 19), B (n = 10)) in all cases. We noted no conversion of the approach, no dislocation and no acetabular loosening. The center of rotation was significantly distalized by a mean of 9 mm (0-23) and significantly medialized by a mean of 18 mm (6-29). The bone graft was fully integrated after 12 months in all cases.

CONCLUSION

Acetabular reconstruction with femoral head autograft in primary THA through a direct anterior approach seems to be a reliable option for the treatment of secondary osteoarthritis in patients with DDH Hartofilakidis grade A and B. Prospective cohort studies with a large sample population and a long-term follow-up are necessary to confirm our findings.

Influence of implantation of a total hip endoprosthesis on the ipsilateral leg alignment: the effect of sex and dysplasia of the hip

INTRODUCTION

Differences in leg and hip morphology exist between sexes and developmental hip dysplasia is known to alter proximal femoral morphology. The purpose of this study was to determine whether existing differences in leg alignment due to sex or developmental hip dysplasia have an effect on changes in leg alignment after total hip arthroplasty.

MATERIALS AND METHODS

30 hip osteoarthritis patients underwent biplanar full-length radiography in the standing position preoperatively and 3 months after total hip arthroplasty. Differences in leg alignment between men and women and between patients with primary hip osteoarthritis and patients with developmental dysplasia before and after surgery were tested using a general linear model for repeated measures.

RESULTS

Implantation of a hip prosthesis had no differential effect on ipsilateral leg alignment in patients with hip osteoarthritis due to dysplasia and in patients with primary hip osteoarthritis. However, patients with hip osteoarthritis due to dysplasia had a 2.1° higher valgus both before and after surgery. After total hip arthroplasty, women had a significantly greater increase in varus angle (1.6° vs. 0°) and femoral offset (10.5 vs. 4.6 mm) compared with men. Because the change in acetabular offset was smaller (2.2 vs. 6.2 mm), the global femoral offset was only increased in women. Femoral torsion was constant for men (15.0° and 16.5°), whereas femoral torsion was significantly reduced in women (19.9° and 13.2°).

CONCLUSIONS

Hip arthroplasty has a greater effect on leg axis in women than in men. The axial leg alignment of women could change from a natural valgus to a varus alignment. Therefore, surgeons should consider the effects of total hip arthroplasty on leg alignment in patients with hip osteoarthritis. Whether these changes in leg alignment are also clinically relevant and lead to premature medial or lateral knee osteoarthritis should be investigated in future work.

TRIAL REGISTRATION

This study was registered with DRKS (German Clinical Trials Register) under the number DRKS00015053. Registered 1st of August 2018.

John Charnley Award: Deep Learning Prediction of Hip Joint Center on Standard Pelvis Radiographs

BACKGROUND

Accurate hip joint center (HJC) determination is critical for preoperative planning, intraoperative execution, clinical outcomes after total hip arthroplasty, and commonly used classification systems in primary and revision hip replacement. However, current methods of preoperative HJC estimation are prone to subjectivity and human error. The purpose of the study was to leverage deep learning (DL) to develop a rapid and objective HJC estimation tool on anteroposterior (AP) pelvis radiographs.

METHODS

Radiographs from 3,965 patients (7,930 hips) were included. A DL model workflow was created to detect bony landmarks and estimate HJC based on a pelvic height ratio method. The workflow was utilized to conduct a grid-search for optimal nonspecific, sex-specific, and patient-specific (using contralateral hip) pelvic height ratios on the training/validation cohort (6,344 hips). Algorithm performance was assessed on an independent testing cohort for HJC estimation comparison.

RESULTS

The algorithm estimated HJC for the testing cohort at a rate of 0.65 seconds/hip based on features in AP radiographs alone. The model predicted HJC within 5 mm of error for 80% of hips using nonspecific ratios, which increased to 83% with sex-specific and 91% with patient-specific pelvic height ratio models. Mean error decreased utilizing the patient-specific model (3.09 ± 1.69 mm, P < .001).

CONCLUSION

Using DL, we developed nonspecific, sex-specific, and patient-specific models capable of estimating native HJC on AP pelvis radiographs. This tool may provide clinical value when considering preoperative component position in patients planned to undergo THA and in reducing the subjective variability in HJC estimation.

LEVEL OF EVIDENCE

Diagnostic, level IV.

Femoral Head Autograft Can Reliably Reconstruct Dysplastic Acetabula Through the Direct Anterior Approach for Total Hip Arthroplasty

Background

Bone deficiencies in dysplastic acetabula create technical difficulties during total hip arthroplasty (THA). Bulk femoral head autograft (FHA) is one method to increase cup coverage and bone stock of the true acetabulum; however, only limited data exist on its efficacy through a direct anterior approach (DAA). This study aimed to evaluate the outcomes of FHA during THA via a DAA in dysplastic hips.

Methods

Retrospective review of 34 patients (41 hips) with hip dysplasia (Crowe I-III) who underwent primary THA via a DAA with FHA at a single institution was performed. Surgical procedures were performed on a traction table with intraoperative fluoroscopy and highly porous-coated cup placement in the true acetabulum. Patients were assessed clinically and radiographically at a minimum of 2 years postoperatively (range, 2 to 7).

Results

The average modified Harris Hip Score improved from 31.9 ± 10.8 to 94.1 ± 5.8, Merle d'Aubigné Hip Score from 7.5 ± 2.8 to 16.6 ± 1.1, and visual analog pain score from 7.9 ± 2.7 to 1.4 ± 1.4 (all P < .001). All hips had an “anatomic” inferomedial cup position postoperatively, with an average increase in horizontal coverage of 43.4%. Mean postoperative limb-length discrepancy improved from 21.8 ± 16.1 mm to 1.6 ± 5.7 mm (P < .001). There were no cases of revision THA, nor complications such as dislocation, infection, or osteolysis.

Conclusion

Reconstructing dysplastic acetabula (Crowe I-III) with FHA during THA can be successfully accomplished via the DAA with increased acetabular bone stock and accurate correction of limb-length discrepancy.

Risk factors of dislocation after total hip arthroplasty in patients with developmental dysplasia of the hip

PURPOSE

Dislocation following total hip arthroplasty (THA) is a well-known complication. However, there is little data on its rate and predictors in patients with developmental dysplasia of the hip (DDH). The current study is aimed to determine the rate and specific risk factors of dislocation following THA in DDH patients.

METHODS

All the medico-surgical records of primary THAs from January 2014 to January 2019 were retrospectively reviewed. They were categorized into three main groups: primary OA, DDH, and others. Pre-operative and post-operative radiographs, past medical and surgical history, and surgical notes were reviewed in DDH cases.

RESULTS

In a total of 171 patients with DDH, 21 suffered from dislocation after THA (12%) which was significantly more frequent than those with primary OA. In univariate analysis, higher grade of dysplasia, smaller head size, intra-operative fracture, Wagner Cone stem, failure of offset restoration, and implanting the cup outside the Lewinnek's safe zone were identified as predictors of dislocation. In multiple regression analysis, however, only higher Crowe grade, intra-operative fracture, and post-operative acetabular offset less than 16 mm were independent predictors of dislocation.

CONCLUSION

Dysplastic hips can be more prone to post-THA dislocation than those with primary OA. Higher grades of dysplasia, failure of offset restoration, and intra-operative fracture can increase the rate of dislocation in this group of patients.

Long-Term Outcomes for Cementless Anatomic Femoral Components, Compared by Area of Porous Coating, in Patients Younger Than 50 Years Treated for Hip Dysplasia

BACKGROUND

We investigated whether the proximal circumferential porous coating of cementless stems would make implant survival of >20 years possible in young patients.

METHODS

Data for patients younger than 50 years with hip dysplasia who had an anatomic stem implanted with a proximal porous coating with hydroxyapatite/tricalcium phosphate were reviewed. Noncircumferential porous (non-C-type) stems were used in 17 hips (13 cases), and circumferential porous (C-type) stems were used in 87 hips (68 cases). Acetabular components with conventional polyethylene were used for all hips. The mean ages at surgery for patients with non-C-type stems and those with C-type stems were 43.3 and 44.7 years, respectively. Stems that had not loosened were retained at the time of acetabular revision. The average duration of follow-up for patients with non-C-type stems was 26.9 years and was 22.3 years for those with C-type stems.

RESULTS

Mean survival rates as determined by the Kaplan-Meier method were 74.9% at 20 years and 59.9% at 25 years for non-C-type stems and were 100% at 20 years and 94.0% at 25 years for C-type stems. The survivorship for C-type stems was significantly higher than that for non-C-type stems (P < .01). Focal osteolysis in the shoulder of 37 hips with C-type stems suppressed the spread of osteolysis to the distal femur.

CONCLUSION

Anatomic femoral stems with a circumferential porous coating provide excellent durability in patients with hip dysplasia who are 50 years of age or younger.

LEVEL OF EVIDENCE

Therapeutic Level IV.

The Three-Dimensional Morphology of Femoral Medullary Cavity in the Developmental Dysplasia of the Hip

OBJECTIVE

This study aimed to assess the morphology of the femoral medullary canal in subjects with developmental dysplasia of the hip (DDH) with the intent of improving the design of femoral stems in total hip arthroplasty.

METHODS

Computed tomography images of 56 DDH hips, which were classified into Crowe I to Crowe IV, and 30 normal hips were collected and used to reconstruct three-dimensional morphology of the femoral medullary cavity. Images of twenty-one cross sections were taken from 20 mm above the apex of the lesser trochanter to the isthmus. The morphology of femoral cavity was evaluated on each cross section for the longest canal diameter, the femoral medullary torsion angle (FMTA), and the femoral medullary roundness index (FMRI).

RESULTS

The Crowe IV group displayed the narrowest medullary canal in the region superior to the end of the lesser trochanter, but then gradually aligned with the medullary diameter of the other groups down to the isthmus. The FMTA along the femoral cavity increased with the severity of DDH, but the rate of variation of FMTA along the femoral canal was consistent in the DDH groups. The DDH hips generally showed a larger FMRI than the normal hips, indicating more elliptical shapes.

CONCLUSION

A femoral stem with a cone shape in the proximal femur and a cylindrical shape for the remainder down to the isthmus may benefit the subjects with severe DDH. This design could protect bone, recover excessive femoral anteversion and facilitate the implantation in the narrow medullary canal.

[Measurement and analysis of leg length in adults with unilateral developmental dysplasia of the hip]

OBJECTIVE

To measure and analyze the radiographic characteristics of the leg length discrepancy in adult patients with unilateral developmental dysplasia of the hip (DDH).

METHODS

The clinical data of 112 patients with unilateral DDH who met the selection criteria between January 2016 and June 2018 were retrospectively analyzed. There were 16 males and 96 females with an age of 20-76 years (mean, 42.9 years). According to the Crowe classification, there were 25 hips of type Ⅰ, 26 hips of type Ⅱ, 15 hips of type Ⅲ, and 46 hips of type Ⅳ (26 hips of type ⅣA without secondary acetabular formation, and 20 hips of type ⅣB with secondary acetabular formation). Full-length X-ray films of the lower limbs in the standing position were used to measure the following parameters: greater trochanter leg length (GTLL), greater trochanter femoral length (GTFL), lesser trochanter leg length (LTLL), lesser trochanter femoral length (LTFL), tibial length (TL), and intertrochanteric distance (ITD). The above parameters on the healthy and affected sides were compared and the difference of each parameter between the healthy and affected sides was calculated. Taking the difference of 5 mm between the healthy side and the affected side as the threshold value, the number of cases with the healthy side was greater than 5 mm and the affected side was greater than 5 mm were counted respectively. The difference of the imaging parameters between the healthy side and the affected side were compared between different Crowe types and between type ⅣA and type ⅣB.

RESULTS

There was no significant difference in GTLL and LTFL between healthy and affected sides ( P>0.05); LTLL and TL of affected side were longer than healthy side, GTFL and ITD were shorter than healthy side, and the differences were significant ( P<0.05). The constituent ratio of long cases on the affected side of TL and LTLL was greater than the constituent ratio of long cases on the healthy side, while the constituent ratio of long cases on the healthy side of GTFL and ITD was greater than the constituent ratio of long cases on the affected side; there was no obvious difference in the constituent ratio of long cases on the healthy side or the affected side of GTLL and LTFL. The comparison between different Crowe types showed that only the difference in TL between type Ⅰ and type Ⅳ was significant ( P<0.05), the difference of each imaging parameter among the other types showing no significant difference ( P>0.05). Compared with type ⅣB, the differences of GTLL, TL, and ITD of type ⅣA were bigger, and the differences were significant ( P<0.05); the differences of other parameters between type ⅣA and type ⅣB were not significant ( P>0.05).

CONCLUSION

In adult unilateral DDH patients, the leg length on the healthy side and the affected side is different, and the difference mainly comes from the TL and ITD, which should be paid attention to in preoperative planning.

Primary Total Hip Replacement in a Case of Unilateral Hypo Plastic Proximal Femur - A Case Report

Introduction:

Primary total hip replacement in hypo plastic proximal femur is difficult due to the presence of a small canal, soft- tissue contracture, fragility of bone, and poor femoral cement mantle when used. Intraoperatively, there could be occurrence of fracture of the femur, inadequate fit, and fill with cement less femoral component.

It is found unilaterally in cases of osteonecrosis of femoral head, post- traumatic, and in sequelae of childhood septic arthritis.

Case Report:

A 45-year- old male patient presented to the OPD with complaints of pain in the left hip and difficulty in walking since for 4 years. The patient had a history of fever and swelling over the left hip in childhood with no treatment taken for the same. X-ray of pelvis with both hips showed deformed femoral head, short neck, narrow femoral canal (Grade 1 Dorr), and arthritic changes in acetabulum. We managed with total hip replacement using Wagner cone stem. Postoperatively, the patient is having good range of motion and having no difficulty in walking and weight- bearing. Functional outcome is good as per Harris hip score.

Conclusion:

Total hip replacement in hypo plastic femur with arthritis is always a challenging problem. It requires surgical expertise and proper implant selection and pre-operative planning, which prevents intraoperative and post-operative complications. Wagner cone stem is a very good option in managing this type of patients.

Acetabulum Reconstruction with TantalumCup and Augments in Dysplastic Hip Type 4 using 3D Printing Technology

Introduction

Acetabular reconstruction in a patient with neglected DDH during complex primary total hip replacement is a challenging procedure to do. We are reporting assessment of acetabular defect in one such patient with pre-operative 3D printing, followed by reconstruction with trabecular metal shell and augments.

Case Report

A 32-year-old female with neglected DDH (Crowe's type 4) reported to us with pain, limp, and shortening of affected limb. Operated somewhere else with THR, she had a missing acetabular component and coral stem in situ at the time of presentation. Acetabular defect was assessed by 3D printing of pelvis following which acetabular reconstruction with tantalum cup and augments along with femoral stem revision was done.

Conclusion

This study confirmed the role of 3D printing pelvis model in meticulous pre-operative planning in patients with complex hip deformities. Reconstruction of acetabular defects with tantalum cup, and augments is a reasonable solution to achieve better function.

Dislocation Height Performs Well in Predicting the Use of Subtrochanteric Osteotomy in Crowe Type IV Hips

Purpose

The purpose of this study was to determine whether dislocation height can predict the use of subtrochanteric osteotomy in patients with Crowe type IV hip dysplasia.

Patients and Methods

We retrospectively included 102 patients affected by unilateral Crowe type IV developmental dysplasia who underwent primary total hip arthroplasty with modular cementless stem from April 2008 to May 2019 in our institution. Based on radiographs and operative notes, we found 62 hip arthroplasties were performed with subtrochanteric osteotomy and 40 without subtrochanteric osteotomy, which were named as the (subtrochanteric osteotomy) STO group and non-STO group, respectively. The predictive values of height of greater trochanter, height of femoral head/neck junction, and distalization of greater trochanter were analyzed using receiver operating characteristic (ROC) curves.

Results

The ROC curves showed that distalization of greater ntrochanter had the highest areas under the ROC curve (AUC), at 0.998. This was followed by height of greater trochanter and height of head/neck junction, which had AUCs of 0.937 and 0.935, respectively. The optimal thresholds of these three indicators were 4.84 cm, 6.05 cm, and 4.26 cm. At the last follow-up, six dislocations occurred (five in the STO group and one in the non-STO group). Four hips were treated by closed reduction and two by open reduction. Three patients (all in STO group) developed femoral nerve palsy with skin numbness on the frontal thigh or tibia and all recovered in a year. At outpatient visit, the limb length was measured. LLD was <1 cm in 83/102, 1–2 cm in 18/102, and >2 cm in 1/102.

Conclusion

This study reveals that indicators of dislocation height are useful in predicting the use of subtrochanteric osteotomy during total hip arthroplasty for Crowe type IV hip dysplasia. However, a comprehensive, multivariate analysis may be required to validate these results.

The severity of developmental dysplasia of the hip does not correlate with the abnormality in pelvic incidence

Background

The purpose of this study was to investigate the association between the severity of Developmental dysplasia of the hip (DDH) and the abnormality in pelvic incidence (PI).

Methods

This was a retrospective study analyzing 53 DDH patients and 53 non-DDH age-matched controls. Computed tomography images were used to construct three-dimensional pelvic model. The Crowe classification was used to classify the severity of DDH. The midpoint of the femoral head centers and sacral endplates were projected to the sagittal plane of the pelvis. The PI was defined as the angle between a line perpendicular to the sacral plate at its midpoint and a line connecting this point to the axis of the femoral heads. Independent sample t-tests were used to compare the differences between the PI of DDH group and the non-DDH controls group. Kendall’s coefficient of concordance was used to determine the correlation between the severity of DDH and PI.

Results

Patients with DDH had a significantly (p = 0.041) higher PI than the non-DDH controls (DDH 47.6 ± 8.2°, normal 44.2 ± 8.8°). Crowe type I patients had a significantly (p = 0.038) higher PI (48.2 ± 7.6°) than the non-DDH controls. No significant difference between the PI in Crowe type II or III patients and the PI in non-DDH controls were found (Crowe type II, 50.2 ± 9.6°, p = 0.073; Crowe type III, 43.8 ± 7.2°, p = 0.930). No correlation was found between the severity of DDH and the PI (r = 0.091, p = 0.222).

Conclusions

No correlation was found between the severity of DDH and the PI. The study confirmed that the PI in DDH (Crowe type I) group was higher than that of the non-DDH control group, while the PI does not correlate with the severity of DDH.

Subtrochanteric Osteotomy in Direct Anterior Approach Total Hip Arthroplasty

Subtrochanteric osteotomy of the femur (STO) is a valuable corrective procedure in hip surgeries. However, STO in traditional posterolateral approach usually encounters complications such as postoperative dislocation, bone non-union, and prosthesis failure. Some relevant pathologies and mechanisms have been identified, but there is sparse evidence for verification. The aim of this video in orthopaedic technique is to test our hypothesis of STO in direct anterior approach to total hip arthroplasty in a complicated hip surgery, and to further illustrate the rationality, reproducibility, and superiority of STO in this minimally invasive and enhanced-recovery approach by presenting a standardized and systemic protocol, as well as operational pearls and pitfalls.

Triaging Total Hip Arthroplasty During the COVID-19 Pandemic

PURPOSE OF REVIEW

The purpose of this review was to evaluate the available literature to determine what may be considered urgent indications for total hip arthroplasty, in the unprecedented setting of the worldwide COVID-19 pandemic.

RECENT FINDINGS

SARS-CoV-2 is a novel coronavirus currently presenting in the form of a global pandemic, referred to as COVID-19. In this setting, multiple states have issued executive orders prohibiting "elective" surgery, including arthroplasty, in order to preserve healthcare resources. However, during this unprecedented reduction in elective surgery, there is likely to be some controversy as to what constitutes a purely "elective" procedure, versus an "urgent" procedure, particularly regarding hip arthroplasty. We reviewed the available literature for articles discussing the most commonly encountered indications for primary, conversion, and revision hip arthroplasty. Based upon the indications discussed in these articles, we further stratified these indications into "elective" versus "urgent" categories. In patients presenting with hip arthroplasty indications, the decision to proceed urgently with surgery should be based upon (a) the potential harm incurred by the patient if the surgery was delayed and (b) the potential risk incurred by the patient in the context of COVID-19 if surgery was performed. The authors present a decision-making algorithm for determining surgical urgency in three patients who underwent surgery in this context. Urgent total hip arthroplasty in the setting of the COVID-19 pandemic is a complex decision-making process, involving clinical and epidemiological factors. These decisions are best made in coordination with a multidisciplinary committee of one's peers. Region-specific issues such as hospital resources and availability of PPE may also inform the decision-making process.

Surgery simulation teaching based on real reconstruction aid versus traditional surgical live teaching in the acquisition of an adult total hip arthroplasty surgical technique for developmental dysplasia of the hip: a randomized comparative study

BACKGROUND

A simulation and model (SM) teaching aid using 3D printing was developed to improve a training course for total hip arthroplasty of adult developmental dysplasia of the hip (adult DDH-THA). We named this new method Surgery Simulation Teaching based on a Real Reconstruction Aid (RRA-SST). A prospective randomized comparison was performed with the traditional surgical live teaching method to evaluate the training effectiveness of RRA-SST for adult DDH-THA.

METHODS

Twenty-six trainees, who were already practicing but were not experienced, participated in the study. We randomly divided the trainees into two groups: Group A (n = 13) received RRA-SST and group B (n = 13) received traditional surgical live teaching. A surgery simulation test and a questionnaire were used for evaluation. Next, each group received training with the other teaching method, and then the test and questionnaire were used again for evaluation.

RESULTS

After the first test, the RRA-SST method was shown to produce better results than the traditional surgical live teaching method. After the second test, the results showed the training effect in both groups reached the same level, which was level as Group A RRA-SST results. Analysis of the questionnaire results showed that the training effect of RRA-SST was higher than that of traditional surgical live teaching, from multiple perspectives.

CONCLUSIONS

The use of RRA-SST improved participant performance according to simulation assessment. RRA-SST can be helpful for trainees who are already practicing but not experienced when developing proficiency in adult DDH-THA surgical techniques.

Total Hip Arthroplasty for Developmental Dysplasia of Hip vs Osteoarthritis: A Propensity Matched Pair Analysis

Background

The purpose of this study was to use the American College of Surgeons National Surgical Quality Improvement Program to compare the perioperative and postoperative outcomes after total hip arthroplasty (THA) for DDH and primary OA via a propensity-matched pair analysis and the valuation of THA between both groups.

Material and Methods

All patients who underwent THA between 2008 and 2016 were identified from National Surgical Quality Improvement Program database via the current procedural terminology (CPT) code. Patients were further identified and stratified based on International Statistical Classification of Diseases and Related Health Problems-9/International Statistical Classification of Diseases and Related Health Problems-10 diagnosis codes for primary OA (n = 115,166) and DDH (n = 603), which included codes for congenital hip dislocation, hip dysplasia, or juvenile osteochondrosis. Demographic variables were used to create 557 propensity-matched pairs.

Results

The DDH group was associated with a significantly longer operative time (120.3 vs 95.9 min), higher postoperative transfusion rate (12% vs 6.6%), and longer hospital length of stay (2.8 vs 2.5 days) compared with the primary OA group (P < .001, P < .001, and P = .002, respectively). There were no statistically significant differences found between the two groups with respect to inpatient complications, discharge disposition (P = .123), readmissions (P = .615), or reoperations (P = .404).

Conclusions

Health policy makers should be cognizant of the higher complexity of THA for DDH when determining whether DDH and primary OA should be in the same bundle. Owing to the limitations of our data set, all the observed associations are likely an underestimate of the true risk posed to patients with severe DDH, as these patients were unable to be stratified in the present analysis.

[Research progress of total hip arthroplasty for patients with sequelae of suppurative hip arthritis]

OBJECTIVE

To summarize the research progress of total hip arthroplasty (THA) in treatment of sequelae of suppurative hip arthritis.

METHODS

The relevant literature was systematically searched and the operation timing, treatments of acetabular and femoral sides, and prosthesis selection in THA for sequelae of suppurative hip arthritis were summarized.

RESULTS

THA is an effective way to treat the sequelae of suppurative hip arthritis. In order to avoid the recurrence of infection, THA is recommended to be performed after 10 years of resting period of hip septic infection. These patients may have acetabulum dysplasia and poor coverage of acetabulum. When performing THA, high position acetabulum, osteotomy of the medial acetabular wall, structural bone graft, Cage, tantalum augment, or three-dimensional printing prosthesis can be chosen. The femoral side may has small medullary cavity, increased femoral neck anteversion, increased femoral neck-stem angle, extend trochanter, and poor bone mass. When performing THA, the femoral osteotomy and appropriate prosthesis can be selected for treatment. The patients with sequelae of suppurative hip arthritis are mostly young, cementless THA is preferred for a better long-term survivorship.

CONCLUSION

THA is an effective method for the sequelae of suppurative hip arthritis, but the operation is difficult and has relative high complication rate. Surgeons should have full understanding.

3D-printed pelvis model is an efficient method of osteotomy simulation for the treatment of developmental dysplasia of the hip

Developmental dysplasia of the hip (DDH) is a congenital or developmental deformation of the hip joint, which may require a high number of surgical interventions. It has been indicated that 3D printing may be used to simulate a fractured pelvis to facilitate the fixation of plates during the surgical procedure. In the present double-blinded randomized clinical trial, the utility of the 3D-printed pelvis model, comprising 3D reconstruction, reverse engineering and rapid prototyping, in the treatment of DDH was evaluated with 3D CT as control. The value of the 3D-printed pelvis model in the surgical management and development of a strategy for an individualized operation for DDH using osteotomy simulation was also assessed. The results indicated that use of the 3D-printed pelvis model increased the success rate of the operation with a shortened surgery time and post-operative recovery time for DDH patients. In addition, the application of the 3D-printed pelvis model allowed for more efficient surgical management of DDH than 3D CT and promoted post-operative recovery of the DDH patients. Pre-operative planning using the 3D-printed pelvis model was feasible for DDH patients. Furthermore, few patients exhibited delayed incision healing, wound infection or nonunion in the DDH group with osteotomy simulation using the 3D-printed pelvis model or 3D-CT. In conclusion, the present study indicated that the 3D-printed pelvis model, including 3D reconstruction, reverse engineering and rapid prototyping, constitutes an efficient tool for pelvic osteotomy simulation, which improves personalized pre-operative planning by providing a visual and accurate osteotomy model for patients with DDH (Chinese Trial Registry No. KCT0012374).

How to restore rotation center in total hip arthroplasty for developmental dysplasia of the hip by recognizing the pathomorphology of acetabulum and Harris fossa?

PURPOSE

To restore rotation center exactly in total hip arthroplasty (THA) is technically challenging for patients with end-stage osteoarthritis due to developmental dysplasia of the hip (DDH). The technical difficulty is attributable to the complex acetabular changes. In this study, we investigated the pathomorphology of acetabulum and Harris fossa of Crowe types I to IV and discussed the method of restoring rotation center of the hip.

METHODS

This study retrospectively reviewed 56 patients (59 hips) who underwent cementless THA due to end-stage osteoarthritis of DDH. The pathomorphology of acetabulum and Harris fossa was observed during operations. Using the preoperative and postoperative pelvic radiographs, the vertical and the horizontal distances of hip rotation center were measured in order to evaluate the effects of restoring rotation center of the hip.

RESULTS

Adult DDH acetabulum could be classified into four basic pathological types which include the shallow cup shape, the dish shape, the shell shape, and the triangular shape. Adult DDH Harris fossa could be classified into four pathological types, including the crack shape, the closed shape, the triangle shape, and the shallow shape, in accordance with the osteophyte coverage. The vertical and horizontal distances of hip rotation center on the pelvic radiographs before and after operations were as follows: the preoperative vertical distance of hip rotation center was (39.96 ± 5.65) mm, and the postoperative one was (13.83 ± 2.66) mm; the preoperative horizontal distance of hip rotation center was (42.15 ± 6.42) mm, and the postoperative one was (28.12 ± 4.56) mm.

CONCLUSIONS

The acetabulum and Harris fossa can display different pathological types on account of different degrees of dislocation and osteophyte hyperplasia in the end-stage osteoarthritis of adult DDH. The hip rotation center can be accurately restored by locating the acetabular center with Harris fossa and acetabular notch as the marks.

Effects of Total Hip Arthroplasty on Axial Alignment of the Lower Limb in Patients with Unilateral Developmental Hip Dysplasia (Crowe type IV)

BACKGROUND

The aim of this study was to evaluate the influence of total hip arthroplasty on axial alignment of the lower limb in adults with unilateral developmental hip dysplasia (Crowe type IV).

METHODS

We retrospectively reviewed medical records of 50 adults who underwent total hip arthroplasty, in which the acetabular cup was placed in the anatomical position. The following parameters were measured before surgery, immediately after surgery, and two years later: mechanical axis deviation (MAD), tibiofemoral angle (TFA), femoral offset, hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (LDFA), mechanical medial proximal tibial angle, height of medial femoral condyle, height of lateral femoral condyle, and leg lengthening. Length of the resected femoral segment was also recorded from medical records.

RESULTS

Preoperative MAD, TFA, HKA, and LDFA of the ipsilateral lower limb showed significant valgus deformity. MAD of the ipsilateral lower limb and valgus inclination were significantly smaller immediately after surgery than before, while TFA, HKA, femoral offset, and LDFA were significantly larger (P < 0.05). These parameters did not differ significantly between immediately after surgery and two years later (P > 0.05). Ipsilateral extremities were extended by a mean of 2.54 cm (range, 0 to 5.35 cm). The mean length of the femoral resected segment was 3.56 cm (range, 2.03 to 5.74 cm). The contralateral lower limb showed marginally smaller MAD and medial proximal tibial angle after surgery than before, but larger LDFA, TAF, and HKA.

CONCLUSIONS

In patients with developmental hip dysplasia who underwent total hip arthroplasty with placement of the acetabular component at the level of the anatomic hip center, axial alignment of the ipsilateral lower limb was immediately altered, and valgus inclination was significantly reduced. The procedure only slightly altered the axial alignment of the contralateral lower limb.

The causes and management of nonunion of femoral subtrochanteric shortening osteotomy in a THA patient: a case report

Background

Total hip arthroplasty (THA) is considerably difficult to perform in patients with Crowe type IV developmental dysplasia of the hip (DDH). Some Crowe type IV DDH patients require a femoral subtrochanteric shortening osteotomy to equalize the length of the lower extremities and decrease the difficulty of intraoperative reduction. Subtrochanteric transverse osteotomy has been proven to have superior clinical efficacy, but some cases of nonunion occur.

Case presentation

We present the case of a 62-year-old male patient who underwent right THA with femoral subtrochanteric transverse osteotomy due to Crowe type IV DDH. Nonunion of the osteotomy occurred during the follow-up period. In July 2017, the patient underwent right THA and femoral subtrochanteric transverse osteotomy due to Crowe type IV DDH. In November 2017, a slight feeling of bone rubbing and slight pain in the hip were reported. The ends of the osteotomy had rotated and united poorly. However, the patient requested to undergo continued observation. In December 2017, the patient reported an obvious sensation of bone rubbing and aggravated hip pain. The ends of the osteotomy had rotated and continued to exhibit nonunion. On December 26, 2017, the patient was treated with plate and screw internal fixation with bone morphogenetic protein (BMP) following our suggestion. In August 2018, the ends of the osteotomy had united after internal fixation was applied.

Conclusions

THA with femoral subtrochanteric transverse osteotomy exhibits good efficacy for the treatment of patients with Crowe type IV DDH. However, postoperative nonunion occurs in a small number of cases. The causes of nonunion should be analysed, and effective measures should be taken to prevent this situation. Plate and screw internal fixation with BMP is an effective treatment for nonunion of the ends of an osteotomy.

Outcomes in 385 developmental dysplastic hips requiring total hip arthroplasty

BACKGROUND

Patients with developmental dysplasia of the hip (DDH) require special surgical considerations for total hip arthroplasty (THA). Despite the difficulties posed by the population's anatomical abnormalities, few large evaluations of postoperative outcomes exist. This study seeks to characterize outcomes following primary THA among patients diagnosed with DDH.

METHODS

A retrospective review was conducted at a tertiary care center on all THA patients between June 2011 and March 2018. Inclusion criteria for this study included any patient diagnosed with DDH undergoing primary THA. Baseline information, operative reports, and postoperative outcomes were pulled from the medical record.

RESULTS

In total, 336 patients (385 hips) undergoing a THA between June 2011 and March 2018 were included. The average age was 52.6 ± 13.0 years and body mass index was 27.8 ± 6.0 kg/m². Most patients were female (82%). The majority of hips (89%, n = 344) were Crowe type 1, followed by 2 (6.9%, n = 26), 3 (2.6%, n = 10), and 4 (1.3%, n = 5). Most hips were Hartofilakidis Class A (83%, n = 320), followed by Class B (15%, n = 59), then C (1.6%, n = 6). Mean follow-up was 24.8 months. Revision THA was required in 19 (4.9%) cases, with the most common indications being infection (2.1%) and periprosthetic fracture (1.0%). Readmission rates were 1.8% (7 hips) and 2.9% (11 hips) at 30-day and 90-day, respectively. The 30-day and 90-day ED visit rates were 1.3% (5 hips) and 2.1% (8 hips), respectively. No complications were seen following 344 (87%) THAs.

CONCLUSION

Despite their surgical complexity, DDH patients on average have notably low rates of revision and dislocation. Longer follow-up is needed to better assess outcomes after THA in this complex patient population.

Three-Dimensional Host Bone Coverage Required in Total Hip Arthroplasty for Developmental Dysplasia of the Hip and Its Relationship With 2-Dimensional Coverage

BACKGROUND

In total hip arthroplasty, the minimum host bone coverage required on the cup for stable fixation has been previously reported; however, the coverage was generally evaluated on a 2-dimensional (2D) image and 3-dimensional (3D) coverage has not been well described.

METHODS

We used postoperative computed tomography images to retrospectively measure 3D cup coverage in 151 hips with developmental dysplasia of the hip that underwent primary total hip arthroplasty. The aims were to (1) determine the minimum requirement of the 3D coverage for stable cup fixation; (2) evaluate the relationship between 2D and 3D coverage; and (3) identify the factors associated with 2D-3D discrepancy, defined as follows: 2D-3D discrepancy = 2D coverage-3D coverage.

RESULTS

All cups showed stable fixation as demonstrated by bone ingrowth with an average postoperative period of 48 months. The minimum 3D coverage was 61.2%, with a mean value of 77.1% ± 6.7% and maximum value of 97.6%. We found a significant positive but poor relationship between 3D and 2D coverage (bone coverage index; r = 0.30). Consequently, the 2D-3D discrepancy varied greatly, with a mean value of -1.6% ± 12.3% (range, -36.5% to 32.2%). Multiple linear regression analyses confirmed that lower cup center and anterior tilt of the pelvis relative to the computed tomography table were independent factors associated with increasing 2D-3D discrepancy.

CONCLUSION

This study showed that 2D coverage, measured on a projected image, carries a risk of overestimation, especially in hips with the aforementioned features.

Apert syndrome: Be aware of the 'dodgy' hip!

Apert syndrome is a rare congenital disorder characterised by craniosynostosis, midface hypoplasia and syndactyly of hands and feet. Here we present a case of a 44-year-old woman, with a genetic diagnosis of Apert syndrome from birth, who presented with symptomatic left-sided hip osteoarthritis secondary to femoral abnormalities. She proceeded to have a total hip replacement. This case report describes the rare occurrence to identify a possible association between Apert syndrome and hip abnormalities.

High-Riding Congenital Hip Dislocation: THA With Unilateral vs Bilateral Transverse Femoral Shortening Osteotomy

BACKGROUND

We argue that 1-stage bilaterally total hip arthroplasty (THA) could be acceptable in bilateral coxarthrosis because of high-riding developmental dysplasia of the hip (DDH).

METHODS

Sixty-nine cases (51 patients) of high-riding DDH in patients who underwent THA from 2010 to 2013 were reviewed. Patients were divided into 2 groups: unilateral (group 1) and 1-stage bilateral surgery (group 2). The clinical measurements were the visual analog scale and Harris Hip Score.

RESULTS

The average follow-up was 37.3 months for group 1 and 38.8 months for group 2. The hospital stay time was 5.2 days in group 1 and 6.2 days in group 2 (P = .334). The mean Harris Hip Score and visual analog scale score were improved significantly after surgery for both groups, and there was no statistically significant difference (P = .988). There was no difference between groups 1 and 2 in terms of complications (P = .137).

CONCLUSION

Our data confirm that 1-stage bilateral transverse osteotomy with THA is an effective method as unilateral and it does not increase the length of patients' hospital stays and features a low risk of postoperative complications in the treatment of patients with high-riding DDH.

INFLUENCE OF MODELING METHODS FOR CARTILAGE LAYER ON SIMULATION OF PERIACETABULAR OSTEOTOMY USING FINITE ELEMENT CONTACT ANALYSIS

Finite element (FE) analysis has been used in the simulation of periacetabular osteotomy (PAO) to predict the improvement of contact pressure concentration in dysplastic hip joint. Since the cartilage layer is difficult to be segmented from CT or MRI images, most hip joint models were assumed to be a simple perfect ball and socket joint. However, the influence of different cartilage modeling methods on the reliability of the simulation has not been assessed. The objective of this study is to elucidate the influence of different cartilage modeling methods on predictions of cartilage layers’ contact pressure by FE contact analysis. In this study, the cartilage layer was generated by applying three typical kinds of modeling methods (spherical, uniform thickness, and midline-based). After comparisons with these cartilage modeling methods, the computational results demonstrate that the cartilage modeling methods have a dramatic influence on predictions of contact pressure in the PAO. The relatively continuous contact pressure distribution and lower peak contact pressure are observed in spherical cartilage modeling method. The discontinuous contact pressure distribution and higher peak contact pressure are obtained in uniform thickness and midline-based cartilage modeling methods. And the degree of discontinuous pressure distribution is even worse in the midline-based cartilage modeling method.

Morphological Analysis of True Acetabulum in Hip Dysplasia (Crowe Classes I-IV) Via 3-D Implantation Simulation

BACKGROUND

The purpose of this study was to investigate the 3-dimensional (3D) morphological features of the true acetabulum in patients with developmental dysplasia of the hip (DDH).

METHODS

Seventy-nine hips-53 in patients with developmental dysplasia of the hip (DDH) and 36 normal hips-were included in the present study. According to the Crowe classification, 26 hips were graded as Class I, 31 were Class II or III, and 22 were Class IV. The anterior pelvic plane was defined to standardize the measurements in the study. A selected virtual cup component was implanted into the true acetabulum of a 3D pelvic model of each hip. The acetabular anteversion angle, effective center-edge (CE) angle, effective Sharp angle, and thickness of the medial wall were measured to provide morphological indices of the true acetabulum. Acetabular sector angles and the component coverage ratio were measured to provide coverage indices.

RESULTS

The acetabular anteversion angle increased with the severity of the DDH. Crowe-II/III hips had the smallest effective CE angle and the largest effective Sharp angle. The mean medial wall thickness was greatest in the Crowe-II/III hips (8.72 mm; 95% confidence interval [CI] = 7.52 to 9.92 mm), intermediate in the Crowe-I hips (7.17 mm; 95% CI = 6.24 to 8.11 mm), and smallest in the Crowe-IV hips (6.05 mm; 95% CI = 4.78 to 7.32 mm). The integrated coverage ratio of the Crowe-II/III hips was significantly less than that of the Crowe-I and IV hips.

CONCLUSIONS

The morphological features of the true acetabulum in patients with DDH can be evaluated comprehensively by using 3D implantation simulation. Segmental bone deficiency was prevalent in the dysplastic hips, especially those in the Crowe-II/III group. Both the severity and the individual morphology of the acetabular dysplasia should be carefully considered in preoperative planning.

Challenges in Total Hip Arthroplasty in the Setting of Developmental Dysplasia of the Hip

BACKGROUND

Developmental dysplasia of the hip (DDH) is a recognized cause of secondary arthritis, which may eventually lead to total hip arthroplasty (THA). An understanding of the common acetabular and femoral morphologic abnormalities will aid the surgeon in preparing for the complexity of the surgical case.

METHODS

We present the challenges associated with acetabular and femoral morphologies that may be present in the dysplastic hip and discuss surgical options to consider when performing THA. In addition, common complications associated with this population are reviewed.

RESULTS

The complexity of THA in the DDH patient is due to a broad range of pathomorphologic changes of the acetabulum and femur, as well as the diverse and often younger age of these patients. As such, THA in the DDH patient may offer a typical primary hip arthroplasty or be a highly complex reconstruction. It is important to be familiar with all the subtleties associated with DDH in the THA population. The surgeon must be prepared for bone deficiency when reconstructing the acetabulum and should place the component low and medial (at the anatomic hip center), and avoid oversizing the acetabular component. Femoral dysplasia is also complex and variable, and the surgeon must be prepared for different stem choices that allow for decoupling of the metaphyseal stem fit from the implanted stem version. In Crowe III and IV dysplasia, femoral derotation/shortening osteotomy may be required. Many complications associated with THA in the DDH patient may be mitigated with careful planning and surgical technique.

CONCLUSION

Performed correctly, THA can yield excellent results in this complex patient population.

Subtrochanteric femoral shortening osteotomy combined with cementless total hip replacement for Crowe type IV developmental dysplasia: a retrospective study

Background

Total hip replacement for high dislocation of the hip presents some difficulties, considering patients’ young ages, the abnormal hip anatomy and the high rate of complications. In this study, we present our experience in terms of clinical and radiological results in the treatment of Crowe type IV hips with subtrochanteric femoral shortening osteotomy and cementless total hip replacement.

Materials and Methods

We retrospectively reviewed 15 patients with Crowe type IV hip dysplasia (two bilateral cases for a total of 17 hips) treated with cementless total hip replacement associated with shortening subtrochanteric osteotomies (nine transversal and eight Z-shape osteotomies) between March 2000 to February 2006. The mean follow-up was 88 months (range 63–133). Harris hip score, leg length discrepancy, neurological status, union status of the osteotomy and the component stability were the criteria of the evaluation. All complications were noted.

Results

The mean HHS improved from 38.3 (range 32–52) to 85.6 (range 69–90). The mean preoperative leg length discrepancy was of 45 mm (range 38–70) and reduced to a mean of 12 mm (range 9–1.6) postoperatively. All osteotomies resulted healed at an average of 12.3 weeks (range 10–15). No cases of delayed union or nonunion were detected. Two patients (11%) showed early symptoms of sciatic nerve palsy which resolved uneventfully in 6 months. There was no migrations and none of the implants required revision.

Conclusions

Cementless THA with shortening subtrochanteric osteotomy is an effective method in the treatment of patients with Crowe type IV development dysplasia of the hip.

Level of evidence

IV.

Does High Hip Center Decrease Range of Motion in Total Hip Arthroplasty? A Computer Simulation Study

BACKGROUND

High placement of a cementless acetabular cup is often required to have sufficient bone coverage in hip dysplasia. We examined whether a high hip center decreases the postoperative range of motion (ROM) in total hip arthroplasty.

METHODS

Using a computer software, ROM and bone coverage were examined in 32 patients with unilateral osteoarthritis of the hip with Crowe type II or III hip dysplasia. The cup was placed at the anatomic hip center and moved vertically in 5-mm increments. Vertical center of rotation (V-COR) was defined as the distance from the head center to the interteardrop line. The required ROM was defined as flexion  ≥110°, internal rotation (IR) at 90° flexion ≥30°, extension ≥30°, and external rotation ≥30°. We determined the V-COR to satisfy the required ROM and cup center-edge angle (Cup-CE) ≥0°.

RESULTS

Only 40.6% of the patients satisfied Cup-CE ≥0° at the anatomic hip center. Bone coverage increased with the peak at 30, 35 mm of V-COR (90.6% satisfied Cup-CE ≥0°) and decreased at ≥40 mm. Higher V-COR resulted in lower range of flexion and IR, but increased the range of extension and external rotation. The cutoff value from the receiver-operating characteristic curve for both flexion and IR was a V-COR of 35 mm.

CONCLUSION

The higher hip center gained more bone coverage but decreased the range of hip flexion and IR. Acceptable V-COR in hip dysplasia was around 35 mm, about 20 mm above the true hip center, in terms of ROM.

Implant survival and patient-reported outcomes after total hip arthroplasty in young patients with developmental dysplasia of the hip

BACKGROUND

Developmental dysplasia of the hip (DDH) is a common cause of hip pain in young patients, and may require treatment with total hip arthroplasty (THA). This study evaluates implant survival and describes patient-reported outcomes after primary THA in DDH patients aged 35 or younger.

METHODS

A retrospective study with prospective follow-up was conducted at a major academic medical centre. Patient charts were reviewed to identify young THA patients with DDH, and follow-up surveys were conducted to determine implant survival and patient-reported outcomes. Kaplan-Meier survival analysis was performed to evaluate implant survival, and the hip disability and osteoarthritis outcome score (HOOS) was used to describe patient-reported outcomes.

RESULTS

This study included 61 patients (75 THAs, 75% follow-up), and the mean time to follow-up was 13 years (range 3-25 years). The 10-year and 20-year implant survival was 87% (95% CI, 78%-94%) and 55% (95% CI, 37%-72%), respectively, and implant survival was significantly better in patients over the age of 25 at the time of surgery (p value &lt;0.01). The mean HOOS patient scores were 83 for pain (SD 20.29), 78 for symptoms (SD 19.72), 83 for ADLs (SD 20.89), and 74 for sports (SD 25.92). Patients that were younger at the time of surgery or required custom implants reported worse HOOS-Symptom scores at follow-up (p value = 0.02).

DISCUSSIONS

Young patients with DDH have good outcomes after surgery. Patient factors and implant characteristics should be considered when predicting implant survival and outcomes after THA in young patients with DDH.

Custom-made femoral implants in total hip arthroplasty due to congenital disease of the hip: a review

Congenital disease of the hip (CDH) is a common reason for the development of secondary osteoarthritis at the hip joint and the need for total hip arthroplasty (THA). The distorted femoral anatomy in patients with CDH in combination with soft tissue considerations and leg length discrepancy complicate the procedure of THA and this sometimes precludes the implantation of classical industry designed femoral stems. In such cases a customised femoral implant must be used in order to optimise the fit of the stem to the femur, to improve strain distribution and to reconstruct hip biomechanics. The present study reviews the preoperative planning, the design and material selection of custom-made implants, the surgical techniques and the reported clinical results of the published literature on the use of custom-made femoral implants in patients with CDH.

Total hip arthroplasty with subtrochanteric femoral shortening osteotomy for high hip dislocation

OBJECTIVE

To evaluate the outcomes of total hip arthroplasty (THA) with subtrochanteric femoral shortening osteotomy for high hip dislocation.

METHODS

In this retrospective study, the results of 24 primary THAs with acetabular reconstruction and subtrochanteric femoral shortening osteotomy in 21 patients with high hip dislocation were evaluated. The acetabula were reconstructed with cemented or uncemented cups and bone grafting. Transverse subtrochanteric femoral shortening osteotomies were applied and the osteotomy sites treated by bone grafting and cable fixation. Assessment was by Hip Harris scores and radiographic evaluation.

RESULTS

The mean follow-up time was 42 months (18-108 months), three cases being lost to follow-up 18-27 months postoperatively. The HHS improved from 47.5 ± 8.7 to 88.5 ± 3.1. The mean length of femoral segments removed was 2.5 ± 0.8 cm (range, 1.0-4.5 cm) and mean acetabular inclination 43° ± 5° (range, 31°-54°). Caudalization of the femoral head center was 3.2 ± 3.0 mm (range, -3 to 12 mm) and lateralization 4.0 ± 4.0 mm (range, -9 to 11 mm). Mean greater trochanter height relative to theoretical hip center was 5.2 ± 1.0 cm (range, 3.5-7.1 cm) preoperatively and 0.2 ± 0.6 cm (range, -0.9 to 1.2 cm) postoperatively. Intraoperative trochanteric fractures occurred in three cases and sciatic nerve palsy in one.

CONCLUSION

THA with subtrochanteric femoral shortening osteotomy is an effective technique for treating high hip dislocation. Its advantages include improvement in limb imbalance and decreased risk of sciatic nerve injury.

Long Term Outcomes of Total Hip Arthroplasty With Custom Made Femoral Implants in Patients With Congenital Disease of Hip

We evaluated the outcomes of total hip arthroplasty in 67 patients (86 hips) with congenital hip disease and excessive abnormal anatomy of the proximal femur with the use of custom-made femoral stems. The design of the stem was based on CT data following the principles of CAD-CAE-CAM technique. No serious complications attributed to the femoral stem were seen. Within a median follow-up of 127.5 months the 10-year survival of any of the components was 95.4% and respective value when aseptic loosening of the stem was considered was 98.1%. Patients with high dislocations had a 10-fold risk for loosening compared to those with low dislocations. No other parameter was associated with outcomes. The clinical and radiological evaluation was in consistency with the above outcomes.

Implication of acetabular width on the anteroposterior pelvic radiograph of patients with developmental dysplasia of the hip

Radiographic parameters that can help acetabular reconstruction during total hip arthroplasty (THA) for patients with developmental dysplasia of the hip (DDH) are few. The radiographs of 138 dysplastic hips that had undergone cementless THA were evaluated regarding the acetabular width above the acetabular component and the coverage of the component by native bone. The acetabular reconstruction process was simulated using 3D models from CT data, and the acetabular component coverage was calculated in 3D space based on the measurement and algorithm we proposed. Significant positive correlation between the acetabular width and the acetabular component coverage was found. Our study introduced a useful parameter, which can mark the superior reference position of the acetabular component for acetabular reconstruction in DDH patients.

Comparison of transverse and modified subtrochanteric femoral shortening osteotomy in total hip arthroplasty for developmental dysplasia of hip: a meta-analysis

BACKGROUND

Subtrochanteric femoral shortening osteotomy is a crucial procedure to prevent nerve injury in total hip arthroplasty for severe developmental dysplasia of the hip. Transverse osteotomy was first applied, and other modified methods have also been reported. Each has its own advantages and limitations, but no definitive conclusions regarding differences in outcomes have been reached to date.

METHODS

We therefore performed a comprehensive meta-analysis to compare the outcomes of different approaches. 37 studies (795 hips) were included in the final analysis. Meta-analysis, subgroup analysis and meta-regression were performed.

RESULTS

Meta-analysis and subgroup analysis showed no significant difference between transverse and modified method. This is further confirmed by meta-regression. Method of osteotomy was found to be not associated with nonunion rate (P = 0.472), as well as other post-operative outcomes including nerve palsy (P = 0.240), dislocation (P = 0.735), revision (P = 0.653) and Harris hip score improvement (P = 0.562). In addition, western countries (P = 0.010) and duration of follow-up more than 5 years (P = 0.014) were associated with higher revision rate.

CONCLUSIONS

Transverse osteotomy and modified osteotomy appear to be equivalent in terms of nonunion, safety and efficacy. Transverse osteotomy may be recommended, due to its simplicity and convenience in adjusting the anteversion angle. Well-designed and large-sample-size randomized controlled trials are expected to confirm and update the findings of this analysis.

Current concept in dysplastic hip arthroplasty: Techniques for acetabular and femoral reconstruction

Adult patients with developmental dysplasia of the hip develop secondary osteoarthritis and eventually end up with total hip arthroplasty (THA) at younger age. Because of altered anatomy of dysplastic hips, THA in these patients represents technically demanding procedure. Distorted anatomy of the acetabulum and proximal femur together with conjoined leg length discrepancy present major challenges during performing THA in patients with developmental dysplasia of the hip. In addition, most patients are at younger age, therefore, soft tissue balance is of great importance (especially the need to preserve the continuity of abductors) to maximise postoperative functional result. In this paper we present a variety of surgical techniques available for THA in dysplastic hips, their advantages and disadvantages. For acetabular reconstruction following techniques are described: Standard metal augments (prefabricated), Custom made acetabular augments (3D printing), Roof reconstruction with vascularized fibula, Roof reconstruction with pedicled iliac graft, Roof reconstruction with autologous bone graft, Roof reconstruction with homologous bone graft, Roof reconstruction with auto/homologous spongious bone, Reinforcement ring with the hook in combination with autologous graft augmentation, Cranial positioning of the acetabulum, Medial protrusion technique (cotyloplasty) with chisel, Medial protrusion technique (cotyloplasty) with reaming, Cotyloplasty without spongioplasty. For femoral reconstruction following techniques were described: Distraction with external fixator, Femoral shortening through a modified lateral approach, Transtrochanteric osteotomies, Paavilainen osteotomy, Lesser trochanter osteotomy, Double-chevron osteotomy, Subtrochanteric osteotomies, Diaphyseal osteotomies, Distal femoral osteotomies. At the end we present author’s treatment method of choice: for acetabulum we perform cotyloplasty leaving only paper-thin medial wall, which we break during acetabular cup impacting. For femoral side first we peel of all rotators and posterior part of gluteus medius and vastus lateralis from greater trochanter on the very thin flake of bone. This method allows us to adequately shorten proximal femoral stump, with possibility of additional resection of proximal femur. Furthermore, several advantages and disadvantages of this procedure are also discussed.

Hospital costs of total hip arthroplasty for developmental dysplasia of the hip

BACKGROUND

Developmental dysplasia of the hip (DDH) is a leading cause of total hip arthroplasty (THA) in younger patients. It is unknown how the hospital costs of THA in patients with DDH compare with patients with degenerative arthritis.

QUESTIONS/PURPOSES

We undertook this study to determine (1) the hospital cost and length of stay associated with primary THA in patients with dysplasia compared with nondysplastic control subjects; (2) the hospital cost and length of stay of THA in severely dysplastic hips compared with mildly dysplastic hips; and (3) perioperative complications in patients with DDH compared with patients without dysplasia.

METHODS

This matched-cohort study included 354 patients undergoing primary THA for DDH and 1029 age-, sex-, and calendar year-matched patients undergoing THA for primary osteoarthritis between 2000 and 2008. DDH severity was measured by the Crowe classification. An institutional database was used to calculate the cost of care. Using line item details (date, type, frequency, and billed charge) for every procedure or service billed at our institution for each patient, bottom-up microcosting valuation techniques were used to generate standardized inflation-adjusted estimates of the cost of each service or procedure in constant dollars. Generalized linear random effects models were used to compare length of stay and costs during hospitalization and the 90-day period after surgery. Query of a longitudinal institutional database was used to identify documented complications.

RESULTS

Patients with DDH undergoing primary THA incurred higher hospital costs than patients with primary osteoarthritis (USD 16,949 versus USD 16,485, p = 0.012). Operating room costs (USD 3471 versus USD 3417, p = 0.0085) and implant costs (USD 3896 versus USD 3493, p < 0.001) were higher in the DDH group compared with the osteoarthritis group. Length of stay was not different between the two groups (4 versus 4 days, p = 0.46). Crowe 4 hips had higher hospital costs than Crowe 1 hips (USD 21,246 versus USD 16,345, p < 0.001) with an associated longer length of stay (5 days versus 4 days, p = 0.0011) and higher implant costs (USD 4380 versus USD 3788, p = 0.0012). There was no detectible difference in 90-day complications in the case group compared with patients undergoing THA for osteoarthritis.

CONCLUSIONS

Hospital cost of primary THA is approximately USD 450 higher in patients with DDH compared with osteoarthritis. Increased severity of dysplasia (Crowe classification) was associated with higher costs.

LEVEL OF EVIDENCE

Level IV, economic and decision analyses. See Guidelines for Authors for a complete description of levels of evidence.