Congenital hip disease in adults: terminology, classification, pre-operative planning and management

Morphological and bone defect mapping analysis of true acetabulum in Crowe type IV hip dysplasia

BACKGROUND

The primary aim of this study was to quantitatively analysis the acetabular morphological feature and 2D/3D coverage of the Crowe IV DDH hip, dividing into subgroups by the false acetabulum. The secondary aim was to propose a 3D bone mapping to determine acetabular bone defect analysis from the perspective of the implanted simulation.

METHODS

A total of 53 Crowe IV hips (27 hips without the false acetabulum in IVa group and 26 hips in IVb group) and 40 normal hips met the inclusion criteria and were retrospectively evaluated. Firstly, the anatomical size and volume of the acetabulum were measured quantitatively. Secondly, through the simulated implantation, morphological assessments of the true acetabulum included Cup-CE, Cup-Sharp, acetabular anteversion angle, and thickness of the medial wall. Last, Acetabular sector angles (ASAs) and the component coverage ratio were measured to provide coverage indices. Further, 3D bone mapping visualization was applied to determine the uncovered component portion distribution.

RESULTS

The anatomic shape and volume of the acetabular triangle were significantly smaller in Crowe IV hips. At the level of the acetabular component center, IVb acetabula were found to be more anteverted and abductive, with smaller Cup-CE and larger Cup-Sharp angles. The coverage sector angles in Crowe IVa hips were larger in the anterosuperior and superior direction, while smaller in the posterosuperior and posterior direction, with no subgroup difference in total component coverage. Both 3D bone mapping and correlation analysis reveal that posterosuperior and posterior bone stock is highly associated with the component coverage.

CONCLUSION

With the presence of the false acetabulum, there existed acetabular anteversion and segmental coverage distinctions between subgroups. During the acetabular reconstruction, management of posterosuperior and posterior bone stock was important for ideal component coverage.

Long-term results of total hip arthroplasty in severe congenital hip disease: A ten- to 20-year follow-up study

INTRODUCTION

The impact of bone deformities, previous surgeries, and the surgical technique in total hip arthroplasty (THA) for congenital dislocation of the hip (CDH) at a long-term has not been clearly defined yet. In this single-centre observational study we sought to assess patients undergoing THA due to osteoarthritis secondary to severe CDH with low or high dislocation ten- to 20-years after surgery. To determine this purpose, we assessed: (1) THA-related complications and reoperations; (2) the clinical outcome, patients' satisfaction and radiological results; and (3) the possible risk factors for reoperation with particular attention to the surgical technique and the influence of prior surgeries.

HYPOTHESIS

We hypothesized that an anatomical reconstruction of the hip would decrease the reoperations rates in patients undergoing THA with severe CDH.

METHODS

Seventy-five patients (85 hips) operated between 1999 and 2012 at our large tertiary hospital were analyzed. Fifty-six hips were diagnosed as low dislocation (group 1) and 29 hips as high dislocation (group 2). The existence of prior surgeries was frequent: group 1, pelvic osteotomies 6 hips, femoral osteotomies 7, tectoplasty (shelf) 6, resection arthroplasty 1 and lowering of the greater trochanter 1; group 2 included pelvic osteotomies 10 hips, femoral osteotomies 10, and a femoral lengthening 2. The number of additional procedures during THA was: group 1 (19/56 [34%]), acetabular roof bone autograft 8 hips, acetabular medial wall autograft 2, hardware removal 6, extended femoral osteotomy 2, and a femoral shortening 1; group 2 (20/29 [69%]), acetabular bone autograft 12 hips, medial autograft 1, hardware removal 1, extended femoral osteotomy 2, and a femoral shortening 4 hips. The clinical and the radiological analysis were compared in both groups for a minimum follow-up of ten years. Cox regression models were used to detect risk factors for reoperation.

RESULTS

Nine patients (13.8%) required reoperation for the following reasons: cup loosening (5 hips), periprosthetic femoral fracture (3) and stem loosening (1); seven had prior surgeries. The 12-year survival rate for reoperation for any reason was 96.3% (95% confidence interval [CI] 91.2-100) in group 1 and 75.7% (95% CI, 65.8-90.8) in group 2 (p=0.003). Patients with high dislocation (p=0.02, hazard ratio [HR]: 6.25, 95% CI, 1.26-30.9) and those with an acetabular component inclination placed out of the target zone between 35° and 50° (p=0.03, HR: 4.27, 95% CI, 1.13-16.1) had a higher risk of reoperation.

DISCUSSION

An optimal placement of the acetabular component decreased the reoperation rates in patients undergoing THA for severe CDH. Hips with high dislocation and the existence of prior surgery can affect THA implantation.

LEVEL OF EVIDENCE

III; retrospective; comparative.

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.

A novel intraoperative acetabular reaming center locating method in total hip arthroplasty for Crowe type IV developmental dysplasia of the hip: a retrospective cohort study

PURPOSE

Although the principles of hip reconstruction are consistent, due to lack of reliable anatomical landmarks, how to decide the acetabular cup reaming centre intraoperatively in Crowe IV patients with developmental dysplasia of the hip (DDH) remains unclear. This study aims to address this question.

METHODS

Fifty-eight Crowe IV patients were enrolled from 2017 to 2019. By examining our previous clinical data, we analyzed the anatomical morphology of Crowe IV acetabulum and proposed a method of locating intraoperative reaming centering for implantation of a standard-sized acetabular cup, which is the upper two thirds of the posterior border of the true acetabulum. All patients included in this study were reamed according to this method. The average postoperative follow-up was 4.1 years (3-5 years). The position of the centre of rotation (COR), cup coverage (CC), and optimal range of joint motion (ROM) were examined by 3D computer simulation measurement. Postoperative complications and hip Harris score were collected and analyzed.

RESULTS

The morphology of the type IV DDH true acetabulum was mostly triangular. The intraoperative reaming centre were centered on the upper two thirds of the posterior border of the true acetabulum. The postoperative 3D CC was 80.20% ± 7.63% (64.68-90.24%, 44-48-mm cup size). The patients' mean Harris score improved from 39.7 ± 20.4 preoperatively to 91.5 ± 8.12 at the last follow-up.

CONCLUSION

Our study demonstrated that satisfactory CC and clinical results could be achieved by implanting a standard-sized cup with the reaming centre on the upper two thirds of the posterior border of the true acetabulum.

Placement of Standard Sized Acetabular Cup Between True and False Acetabulum in Patients with Crowe III/IV Dysplasia: A Safe Option in THA Without Femoral Osteotomy

Introduction

There is no consensus in literature on the surgical treatment of patients with Crowe type III/IV patients. Each arthroplasty procedure has its own advantages and disadvantages. In this study by placing the acetabular cup between the true and false acetabulum, we aimed to share our experience about criteria of patient selection, surgical technique, and mid-term results of THA (total hip arthroplasty) in which the risk of dislocation was minimized using a standard-sized acetabular cup.

Materials and Methods

We reviewed the clinical and radiographic data of the patients with Crowe type III/IV treated by cementless THA without femoral shortening osteotomy from January 2015 to January 2020. The clinical (Harris hip score, Trendelenburg sign, limb lengths) and radiographic (AP/L hip X-ray, 3D CT) examinations before surgery; 1, 3 months and 1 year after the surgery were evaluated. All postsurgical complications were noted.

Results

Among all, 268 patients met the inclusion criteria. Thirty-two patients (11.9%) were male and 236 (88.1%) were female. Mean age was 46.8 years. Mean follow-up duration was 42.4 (26-57) months. Mean Harris Hip score (HHS) was 49.7 and Trendelenburg sign was positive in all patients preoperatively. In the final evaluation, mean HHS significantly improved to 80.2 (p < 0.005) and none of the patients had Trendelenburg sign. Mean lengthening of the operated leg was 4.3 cm.

Conclusion

Total hip arthroplasty with placement of acetabular cup between true and false acetabulum can be successfully preferred in selected patients with Crowe III/IV dysplasia.

Identification of screw spacing on pediatric hip locking plate in proximal femoral osteotomy

This study describes a computational analysis technique for evaluating the effect of screw spacing and angle on the pediatric hip locking plate system in proximal femoral osteotomy in pediatric patients having DDH with an aberrant femoral head and femoral angle. Under static compressive load conditions, the stresses of the screw and bone were examined as the screw spacing and angle changed. The spacing and angle of various screws were specifically considered as variables in this study based on the pile mechanism studied in civil engineering. As with the group pile mechanism, the tighter the screw spacing under static compressive loads, the more the overlapping effect between the bone stresses and the screws develops, increasing the risk of injuring the patient's bone. Therefore, a series of simulations was performed to determine the optimal screw spacing and angles to minimize the overlapping effect of bone stress. In addition, a formula for determining the minimum screw spacing was proposed based on the computational simulation results. Finally, if the outcomes of this study are applied to pediatric patients with DDH in the pre-proximal femoral osteotomy stage, post-operative load-induced femur damage will be reduced.

Total Hip Arthroplasty in Patients with Crowe III/IV Developmental Dysplasia of the Hip: Acetabular Morphology and Reconstruction Techniques

The severe anatomic deformities render acetabular reconstruction as one of the greatest challenges in total hip arthroplasty (THA) for patients with Crowe III/IV developmental dysplasia of the hip (DDH). Thorough understanding of acetabular morphology and bone defect is the basis of acetabular reconstruction techniques. Researchers have proposed either true acetabulum position reconstruction or high hip center (HHC) position reconstruction. The former can obtain the optimal hip biomechanics, including bulk femoral head autograft, acetabular medial wall displacement osteotomy, and acetabular component medialization, while the latter is relatively easy for hip reduction, as it can avoid neurovascular lesions and obtain more bone coverage; however, it cannot achieve good hip biomechanics. Both techniques have their own advantages and disadvantages. Although there is no consensus on which approach is better, most researchers suggest the true acetabulum position reconstruction. Based on the various acetabular deformities in DDH patients, evaluation of acetabular morphology, bone defect, and bone stock using the 3D image and acetabular component simulation techniques, as well as the soft tissue tension around the hip joint, individualized acetabular reconstruction plans can be formulated and appropriate techniques can be selected to acquire desired clinical outcomes.

Intraoperative two-stage evaluation of muscle contractures in Crowe type IV hips in total hip arthroplasty (a new surgical technique)

BACKGROUND

It is important to maintain soft-tissue balance and prevent muscle contractures after hip reduction during total hip arthroplasty (THA) in patients with Crowe type IV developmental dysplasia of the hip (DDH). To make such hips functional and durable, the techniques to achieve soft-tissue balance were studied to create an algorithm for intraoperative 2-stage evaluation of muscle contractures, specifying the optimal order for contracture release.

METHODS

Between February 2011 and March 2015, we evaluated 64 patients (75 hips) with DDH for muscle contractures as they underwent THA. Following acetabular implantation, femoral osteotomy was applied of various lengths according to limb-length discrepancy. First, the distal part of the femur was prepared by broaching, and the hip was then reduced. The tensor fascia lata, rectus femoris, sartorius, hamstrings, and adductor muscles were evaluated, and any contractures were released. A trial conjoining of the distal and proximal parts of the femur was made, and the hip was reduced again. Finally, the iliopsoas and abductor muscles were evaluated, and contractures were released.

RESULTS

The mean follow-up duration was 4.6 years. Preoperative and postoperative Harris Hip Scores were 52 and 87, respectively. Limb-length discrepancy was mean 4.2 cm preoperatively, and <1 cm postoperatively. All contractures were released according to our newly developed algorithm.

CONCLUSIONS

It is challenging to pinpoint the main muscle causing contractures, because other muscles acting on the hip joint have similar secondary functions. The method we describe here may provide better and more specific restoration of muscle function in a hypoplastic hemipelvis in DDH.

Cementless modular total hip arthroplasty with subtrochanteric transverse shortening osteotomy for high hip dislocations

Background

Performing a total hip arthroplasty for a high hip dislocation is technically demanding and presents several challenges, with appropriate evaluation of the bone morphology of the hip and proper implant selection being critical for successful outcomes.

Objective

The purpose of our study was to evaluate the clinical and radiographic outcomes of cementless modular total hip arthroplasty for the treatment of high hip dislocations with sub-trochanteric transverse shortening osteotomy.

Methods

Sixty-eight hips with a high hip dislocation, were treated using a sub-trochanteric transverse shortening osteotomy and cementless modular total hip arthroplasty, retrospectively reviewed. Hip function was assessed using the Harris hip score, with hip abduction strength evaluated using the Trendelenburg test. Radiographic assessment included the measurement of leg length discrepancy, identification of implant loosening, localization of the hip center, and union at the osteotomy site.

Results

The mean follow-up period was 12.9 (range 5.2–16.8) years. The mean Harris hip score improved from a pre-operative score of 48.6 ± 3.6 to 82.4 ± 4.2 (p < 0.05). The hip was within the true acetabulum in all patients, postoperatively. Osteotomy union was achieved in 67 of the 68 hips (98.5%) in a mean latency of 12.5 ± 0.6 weeks. The mean length of femoral shortening was 66.5 ± 4.5 mm, with a mean pull-down length of the proximal part of 35.5 ± 3.5 mm.

Conclusion

For the treatment of high hip dislocations with satisfactory clinical outcomes, the modular stem offers an adjustable anteversion angle to restore sufficient rotational stability and the transverse osteotomy provides sufficient compression pressure across the osteotomy site to facilitate union.

Trial registration It was a retrospective study and approved by Istanbul Research and Training Hospital institutional Ethics Review Board (772-05/02/2016).

[Effectiveness of total hip arthroplasty in patients with a history of hip preservation surgery with secondary osteoarthritis for developmental dysplasia of the hip]

Objective

To evaluate early to medium-term effectiveness of total hip arthroplasty (THA) in patients with a history of hip preservation surgery with secondary severe osteoarthritis for developmental dysplasia of the hip (DDH).

Methods

The clinical data of 25 DDH patients (31 hips) who had severe osteoarthritis after hip preservation surgery and received THA between September 2009 and March 2021 were retrospectively analyzed. There were 1 male and 24 females; the age ranged from 18 to 65 years, with an average age of 43 years; 8 hips were classified into Crowe type Ⅰ, 9 hips were type Ⅱ, 3 hips were type Ⅲ, and 11 hips were type Ⅳ. The time between osteotomy and THA ranged from 31 to 51 years, with an average of 31.96 years. Preoperative hip flexion range of motion was (69.31±29.72)°, abduction range of motion was (24.00±14.79)°; and Harris hip score was 45.3±15.5. Postoperative Harris hip score, hip range of motion, complications, radiographic findings, and implant survival rate were analyzed.

Results

Patients in both groups were followed up 2-132 months, with an average of 51 months. During the follow-up, periprosthetic fracture occurred in 1 case; there was no complication such as dislocation, periprosthetic infection, nerve palsy, or deep vein thrombosis. At last follow-up, the hip flexion range of motion was (109.52±11.17)°, abduction range of motion was (41.25±5.59)°, showing significant differences when compared with preoperative values ( t=8.260, P=0.000; t=6.524, P=0.000). The Harris hip score was 91.5±4.1, and the difference was significant when compared with preoperative score ( t=11.696, P=0.000); among them, 13 cases were excellent and 12 cases were good. Radiographic evaluation showed that the center of acetabular rotation moved up 0-18 mm (mean, 6.35 mm). The cup abductor angle was 28°-49° (mean, 37.74°) and the coverage rate was 69.44%-98.33% (mean, 81.04%). All femoral stems were fixed in neutral position without varus or valgus. No osteolysis, radiolucent line, or implant migration was observed. By the end of follow-up, none of the patients underwent revision and the survival rate of prothesis was 100%.

Conclusion

THA is still the gold standard for the treatment of DDH patients with secondary osteoarthritis after hip preservation surgery. The postoperative joint function can be rapidly restored, the patients' quality of life can significantly improve, and the early to medium-term survival rate of the prosthesis is satisfactory.

The accuracy of digital templating in cementless total hip arthroplasty in dysplastic hips

Background

Total hip arthroplasty (THA) for developmental dysplasia of the hip (DDH) is a complex procedure due to associated anatomical abnormalities. We studied the extent to which preoperative digital templating is reliable when performing cementless THA in patients with DDH.

Methods

We templated and compared the pre- and postoperative sizes of the acetabular and femoral components and the center of rotation (COR), and analysed the postoperative cup coverage, leg length discrepancy (LLD), and stem alignment in 50 patients (56 hips) with DDH treated with THA.

Results

The implant size exactly matched the template size in 42.9% of cases for the acetabular component and in 38.2% of cases for the femoral component, whereas the templated ±1 size was used in 80.4 and 81.8% of cases for the acetabular and femoral components, respectively. There were no statistically significant differences between templated and used component sizes among different DDH severity levels (acetabular cup: p = 0.30 under the Crowe classification and p = 0.94 under the Hartofilakidis classification; femoral stem: p = 0.98 and p = 0.74, respectively). There were no statistically significant differences between the planned and postoperative COR (p = 0.14 horizontally and p = 0.52 vertically). The median postoperative LLD was 7 (range 0–37) mm.

Conclusion

Digital preoperative templating is reliable in the planning of cementless THA in patients with DDH.

Three-dimensional morphological study of the proximal femur in Crowe type IV developmental dysplasia of the hip

Background

When performing femoral reconstruction in patients with Crowe type IV developmental dysplasia of the hip (DDH), anatomical deformity presents many technical challenges to orthopedic surgeons. The false acetabulum is suggested to influence load transmission and femoral development. The aim of this study was to describe the morphological features of dysplastic femurs in Crowe type IV DDH and further evaluate the potential effect of the false acetabulum on morphological features and medullary canal of Crowe type IV femurs.

Methods

We analyzed preoperative computed tomography scans from 45 patients with 51 hips (25 hips without false acetabulum in the IVa group and 26 hips with false acetabulum in the IVb group) who were diagnosed with Crowe type IV DDH and 30 normal hips in our hospital between January 2009 and January 2019. Three-dimensional reconstruction was performed using Mimics software, and the coronal femoral plane was determined to evaluate the following parameters: dislocation height, dislocation ratio, height of the femoral head (FH), height of the greater trochanter (GT), GT–FH height discrepancy, height of the isthmus, neck-shaft angle, femoral offset and anteversion of the femoral neck. The mediolateral (ML) width, anterolateral (AP) width and diameter of medullary canal of the proximal femur were measured on the axial sections. Further, canal flare index (CFI), metaphyseal-CFI and diaphyseal-CFI were also calculated.

Results

Compared with the normal femurs, the Crowe type IV DDH femurs had a higher femoral head, larger GT–FH height discrepancy, larger femoral neck anteversion, higher isthmus position and smaller femoral offset. Dislocation height and dislocation rate were significantly larger in the IVa DDH group (65.34 ± 9.83 mm vs. 52.24 ± 11.42 mm). Further, the IVb femurs had a significantly lower isthmus position, larger neck-shaft angle and smaller femoral neck anteversion than IVa femurs. The ML, AP canal widths and the diameter of medullary canal in both DDH groups were significantly smaller than the normal group. Dimensional parameters of IVa femurs were also narrower than IVb femurs in most sections, but with no difference at the level of isthmus. According to the CFIs, the variation of proximal medullary canal in IVb femurs was mainly located in the diaphyseal region, while that in IVa femurs was located in the whole proximal femur.

Conclusions

High dislocated femurs are associated with more anteverted femoral neck, smaller femoral offset and narrower medullary canal. Without stimulation of the false acetabulum, IVa DDH femurs were associated with higher dislocation and notably narrower medullary canal, whose variation of medullary canal was located in the whole proximal femur.

One-Stage Total Hip Arthroplasty with Modular S-ROM Stem for Patients with Bilateral Crowe Type IV Developmental Dysplasia

Objective

The aim of the present paper was to evaluate the results of one‐stage total hip arthroplasty (THA) for patients with bilateral Crowe type IV developmental dysplasia of the hip (DDH).

Methods

Data for 58 patients (116 hips) with bilateral Crowe type IV DDH who had one‐stage THA performed by the same surgeon during the period of April 2008 to February 2019 were retrospectively reviewed. The mean age of the patients was 37.3 years; 5 were men and 53 were women. All patients underwent THA through the posterolateral approach using the Pinnacle acetabular cup, a ceramic‐on‐ceramic bearing, and the modular S‐ROM stem. Subtrochanteric shortening osteotomy was performed on 86/116 hips. Intraoperative conditions were recorded. Radiographic and functional outcomes were evaluated, and complications were recorded.

Results

All patients were followed up for an average of 71.3 ± 37.6 months (range, 12–140). The mean operative time was 276.5 ± 57.9 min (range, 175–540). The mean intraoperative blood loss was 933.6 ± 400.8 mL (range, 300–2000). The mean transfusion requirement was 1778 ± 798.0 mL (range, 575–4550). The mean length of hospital stay was 8.6 ± 3.7 days (range, 5–22). At the final follow‐up, no loosening of acetabular and femoral components was observed. No osteolysis and heterotopic ossification occurred. The mean Harris hip scores were improved from 55.4 ± 14.3 preoperatively to 91.3 ± 4.2 postoperatively (P < 0.001) In terms of complications, no perioperative deaths were recorded. Deep vein thrombosis occurred in 1 hip, with no pulmonary embolism. Intraoperative femur fracture occurred in 3 hips, nerve injury in 1 hip, and leg length discrepancy in 1 patient. Postoperative dislocation occurred in 5 hips and nonunion in 1 hip.

Conclusion

Our data demonstrated that one‐stage bilateral THA for bilateral Crowe type IV DDH is feasible and can effectively restore hip function.

Three-dimensional femoral morphology in Hartofilakidis type C developmental dysplastic hips and the implications for total hip arthroplasty

PURPOSES

The aim of this study was to describe and compare the femoral morphologies of Hartofilakidis types C1 and C2 developmental dysplasia of the hip (DDH), and discuss the potential influence on subsequent total hip arthroplasty (THA).

METHODS

We analyzed preoperative CT data from 81 patients (42 C1 and 39 C2 subtypes) who underwent THA for arthritis secondary to Hartofilakidis type C DDH. The CT data was three-dimensionally reconstructed and measured of following parameters: neck-shaft angle, femoral neck length, anteversion, medial inclination, femoral offset, height of the greater trochanter and femoral head, mediolateral (ML) and anteroposterior (AP) widths of the medullary canal. The canal flare indices and ML-to-AP ratio were further calculated. We also reviewed surgical and follow-up records to compare the different implants utilized and the clinical results between C1 and C2 hips.

RESULTS

The C2 femurs had a significantly lower neck-shaft angle (119.0° vs. 124.0°), shorter femoral neck (37.0 mm vs. 41.2 mm), larger medial cortical inclination (158.8° vs. 149.1°), and higher position of the greater trochanter. The C2 femurs were narrower and had a smaller canal flare index (2.88 ± 0.50) than C1 femurs (3.64 ± 0.69). The ML-to-AP ratio of the proximal femoral medullary canal was significantly smaller in the C2 group. Accordingly, C2 femurs required thinner stems, more non-sprouted sleeves, and had a higher rate and required a longer length of shortening osteotomies. At an average follow-up of 36.0 months, the C1 and C2 groups had a similar Harris Hip Score (83.5 ± 14.3 vs. 84.2 ± 9.8, P = 0.771) and no stem loosening occurred in either group.

CONCLUSION

C1 and C2 proximal femurs have substantial differences in the coronal, sagittal, and axial planes. In the setting of THA, C2 femurs may therefore require thinner stems, more non-sprouted sleeves, and have a higher rate and require a longer length of shortening osteotomies.

Comparison of the long-term outcome of cemented Charnley low-friction arthroplasty with hybrid arthroplasty in patients with congenital hip disease

AIMS

To our knowledge, no study has compared the long-term results of cemented and hybrid total hip arthroplasty (THA) in patients with osteoarthritis (OA) secondary to congenital hip disease (CHD). This is a demanding procedure that may require special techniques and implants. Our aim was to compare the long-term outcome of cemented low-friction arthroplasty (LFA) and hybrid THA performed by one surgeon.

PATIENTS AND METHODS

Between January 1989 and December 1997, 58 hips (44 patients; one man, 43 woman; mean age 56.6 years (25 to 77)) with OA secondary to CHD were treated with a cemented Charnley LFA (group A), and 55 hips (39 patients; two men, 37 women; mean age 49.1 years (27 to 70)) were treated with a hybrid THA (group B), by the senior author (GH). The clinical outcome and survivorship were compared.

RESULTS

At all timepoints, group A hips had slightly better survivorship than those in group B without a statistically significant difference, except for the 24-year survival of acetabular components with revision for aseptic loosening as the endpoint, which was slightly worse. The survivorship was only significantly better in group A compared with group B when considering reoperation for any indication as the endpoint, 15 years postoperatively (74% vs 52%, p = 0.018).

CONCLUSION

We concluded that there was not a substantial difference at almost any time in the outcome of cemented Charnley LFAs compared with hybrid THAs when treating patients with OA of the hip secondary to CHD. We believe, however, that after improvements in the design of components used in hybrid THA, this could be the method of choice, as it is technically easier with a shorter operating time. Cite this article: Bone Joint J 2019;101-B:1050-1057.

How does anteroposterior cup placement affect bone coverage and range of motion in primary total hip arthroplasty for hip dysplasia?

BACKGROUND

Due to anterior bone defects, high and/or posterior placement of an acetabular cup is often required to achieve sufficient coverage in patients with hip dysplasia. We examined whether posterior cup placement affected the postoperative range of motion (ROM) in primary total hip arthroplasty (THA).

METHODS

Using computer software, bone coverage and ROM were examined in 32 patients with unilateral osteoarthritis of the hip with Crowe type II or III hip dysplasia. We determined the cup position to satisfy cup center-edge (Cup-CE) angle ≥0° and the required ROM. The cup was placed at the anatomic hip center and moved in 2-mm increments anteroposteriorly and 10-mm increments vertically.

RESULTS

At vertical anatomic hip center, less than 68.8% hips fulfilled Cup-CE ≥0° regardless of anteroposterior position. Significantly more hips at higher hip center with posterior cup placement achieved Cup-CE ≥0° than hips at vertical anatomic hip center, and 10 mm higher hip center was the most suitable for achieving bone coverage. However, posterior and superior cup placement significantly decreased the flexion and IR due to early bone impingement, whereas ER and extension were not affected. A smoothing spline curve demonstrated that more posterior cup placement than 4.8 mm and 3.6 mm did not satisfy the required ROM at 10 mm and 20 mm higher hip center, respectively.

CONCLUSIONS

Posterosuperior cup placement gained more bone coverage but decreased the range of hip flexion and internal rotation. Consequently, posterosuperior cup placement did not satisfy the required ROM.

[Challenges of primary hip arthroplasty with high hip dislocation]

BACKGROUND

Endoprosthetic care of high hip dislocation is a surgical challenge. The hip anatomy is greatly altered in these patients, including a rather flat and small acetabulum with impaired bone quality and a relevant chance of a bony defect of the acetabular roof. Additionally, the front coverage and in some cases even the dorsal coverage of the hip are missing. The proximal femur is characterized with an increased antetorsion, a coxa valga position and an enlarged greater trochanter. The medullary cavity is narrowed, the offset is reduced, and the absolut leg length can be enlarged. Further anatomic variations can have been caused by previous surgeries.

AIM OF THE TREATMENT

The goal of the endoprosthetic care is the re-creation of a hip with an anatomic center of rotation, an anatomic offset and equal leg length.

TREATMENT

This can be achieved by a medial shift of the acetabular cup. An acetabular osteotomy including central cancellous bone graft or a bony graft to reinforce the acetabular roof might be necessary. In cases in which an anatomic acetabular cup placement is not possible, a more cranial placement can be done. Further strategies that are essential in several cases are shortening or re-orientation osteotomies of the femur, reaming of the medullary cavity and correct implant selection. Additionally, thorough soft tissue management is of main importance. Generally, the surgery should be well prepared preoperatively.

Morphometric geometrical analysis to determine the centre of the acetabular component placement in Crowe type IV hips undergoing total hip arthroplasty

AIMS

We analyzed the acetabular morphology of Crowe type IV hips using CT data to identify a landmark for the ideal placement of the centre of the acetabular component, as assessed by morphometric geometrical analysis, and its reliability.

PATIENTS AND METHODS

A total of 52 Crowe IV hips (42 patients; seven male, 35 female; mean age 68.5 years (32 to 82)) and 50 normal hips (50 patients; eight male, 42 female; mean age 60.7 years (34 to 86)) undergoing total hip arthroplasty were retrospectively identified. In this CT-based simulation study, the acetabular component was positioned at the true acetabulum with a radiological inclination of 40° and anteversion of 20°. Acetabular shape and the position of the centre of the acetabular component were analyzed by morphometric geometrical analysis using the generalized Procrustes analysis.

RESULTS

The acetabular shapes of Crowe IV hips were distinctively triangular; the ideal position of the centre of the acetabular component was superior on the posterior bony wall. The first and second relative warps explained 34.2% and 18.4% of the variance, respectively, compared with that of 28.6% and 18.0% in normal hips. We defined the landmark as one-third the distance from top on the posterior bony wall in Crowe IV hips. The average distance from the centre of the acetabular component was 5.6 mm.

CONCLUSION

Crowe IV hips are distinctively triangular; the point one-third from the top on the posterior bony wall was a useful landmark for placing the acetabular component.

Factors affecting the return to work of total hip arthroplasty due to of developmental hip dysplasia in in young patients

Introduction

The aim of this study was to examine the factors affecting return to work after Total hip arthroplasty (THA) applied for coxarthrosis due to developmental hip dysplasia (DDH).

Methods

The study included 51 patients aged <60 years in the period 2004-2010. The demographic information was recorded for all patients and the pre-postoperative Modified Harris score, EQ-5D, EQ-5D VAS and Grimby activity score. With an evaluation of the current employment status at the final follow-up examination.

Results

Preoperatively, 21 patients were employed, 16 were unemployed and 14 were housewives, none of whom were able to perform housework tasks. Postoperatively, 30 patients were employed and 10 were unemployed. One of the previously employed patients decided preoperatively to retire and was therefore not employed postoperatively. Of the 14 housewives, 9 were able to undertake the housework themselves postoperatively. The mean time of return to work was 13.4 weeks. Factors affecting finding work postoperatively were determined to be body mass index, National Occupational Level, whether or not osteotomy was applied and the preoperative duration of unemployment.

Conclusions

As coxarthrosis associated with DDH develops earlier than primary coxarthrosis, these patients undergo surgery at a younger age and the vast majority are of working age. THA applied for coxarthrosis on the basis of DDH enables most patients to return to their preoperative work and offers the opportunity of finding work to some of those who were unemployed. This increases the contribution of these patients to the national economy.

Prevalence of Developmental Dysplasia of the Hip in Chinese Adults: A Cross-sectional Survey

Background:

The prevalence of developmental dysplasia of the hip (DDH) is unknown in China. We aimed to determine the prevalence of DDH in Chinese adults.

Methods:

In this study, we performed a cross-sectional survey of a nationally representative sample of Chinese adults. All participants underwent questionnaire investigation, physical examination, and X-ray examination. Factors associated with DDH were analyzed with logistic regression.

Results:

We invited 29,180 individuals aged 18 years and over to participate, randomly selected from 18 primary sampling units (street districts in urban areas and townships in rural areas). The survey and examination were completed in 25,767 people (10,296 men and 15,471 women). DDH was diagnosed in 391 people, yielding an overall DDH prevalence of 1.52%. Based on this information, we estimate the number of individuals with DDH in China to be approximately 16.05 million. DDH prevalence increased with age (odds ratio = 1.53 [1.03–2.27], P = 0.036), was significantly higher among women than men (2.07% vs. 0.75%, P < 0.001), and was higher among rural residents than urban residents (1.75% vs. 1.29%, P < 0.001). Economic development was independently associated with the presence of DDH. There was no evidence of an association between body mass index alone, education, or current smoking or drinking and risk of DDH (P > 0.05).

Conclusions:

DDH has become an important public health problem. Special attention should be paid to residents with DDH. Screening for DDH should be performed in China.

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.

Developmental hip dysplasia treated by total hip arthroplasty using a cementless Wagner cone stem in young adult patients with a small physique

BACKGROUND

Developmental hip dysplasia (DDH) may lead to severe acetabular and femoral abnormalities that can render total hip arthroplasty (THA) challenging, especially in DDH patients with a small physique. Most conventional cemented or cementless femoral components are often difficult to implant in the narrow femoral canal and require slight version correction during surgery. The aim of this study was to present the mid-term results of THA in the treatment of DDH patients with a small physique using a cementless Wagner cone prosthesis (Zimmer®, US).

METHODS

Between January 2006 and March 2010, we retrospectively reviewed 50 patients who were treated at our center. A total of 50 patients (52 hips; 45 women, five men; mean age 32.5 years; range 27 to 38 years) who underwent THA were observed. The mean femoral medullary canal dimension at the isthmus was 7.6 mm (range 6.0 to 8.7). According to the Crowe classification, 19 hips presented dysplasia of grade I, while 33 presented dysplasia of grade II. All patients were treated with THA using a cementless Wagner cone prosthesis. Clinical and radiologic evaluations were performed on all patients.

RESULTS

The mean duration of follow-up was 7.7 years (range 5.4 to 10.5). The Harris hip score (HHS) improved from 63 ± 9 (range 55 to 70) pre-operatively to 92 ± 8 (range 88 to 100) at the last follow-up. The HHS at the most recent follow-up was excellent in 66% of patients (34 hips), good in 26% (14 hips), fair in 6% (3 hips), and poor in 2% (1 hip). Radiographic evaluation demonstrated excellent osteointegration of the implants. Stem subsidence was present in three stems, and the range of stem subsidence was 2 mm in two stems (3.9%) and 3 mm in one stem (1.9%). Femoral osteolysis was observed in nine hips (18%) in the proximal zones, and no distal osteolysis was noted. Heterotopic ossification was observed in three hips (5.8%); of these, two were classified as Brooker's grade 1, and one was classified as Brooker's grade 2 at the most recent follow-up. None of the implants were revised.

CONCLUSIONS

Based on the tapered shape and free setting of anteversion, the Wagner cone femoral stem facilitates its implantation in dysplastic hips. Therefore, this series of short stems with a smaller diameter can ensure safe implantation in narrow medullary canals, especially in young DDH patients with a small physique.

TRIAL REGISTRATION

Registration Number: ChiCTR-ORC-17011181 . Reg Date: 2017-04-19 00:44:59 Retrospective registration.

An attempt to throw light on congenital hip disease terminology and anticipation of clinical outcomes when treated with total hip arthroplasty

The terminology of the wide spectrum of hip deformities seen during the neonatal, infantile and adult life period remains controversial, mainly due to the indiscriminate use of the terms dysplasia, subluxation, congenital hip disease, developmental hip disease, congenital dislocation, etc. This has a serious implication on the anticipation of clinical outcomes, complications and comparison of different reconstructive techniques when these patients are treated with total hip arthroplasty in adulthood. Journals, specialising in this field, should publish homogeneous series (type of the disease, reconstruction technique, implants) in order to clarify arguments and anticipate clinical outcomes.

Lessons learned from study of congenital hip disease in adults

Orthopaedic surgeons specialising in adult hip reconstruction surgery often face the problem of osteoarthritis secondary to congenital hip disease (CHD). To achieve better communication among physicians, better treatment planning and evaluation of the results of various treatment options, an agreed terminology is needed to describe the entire pathology. Furthermore, a generally accepted classification of the deformities is necessary. Herein, the authors propose the use of the term “congenital hip disease” and its classification as dysplasia, low dislocation and high dislocation. Knowledge of the CHD natural history facilitates comprehension of the potential development and progression of the disease, which differs among the aforementioned types. This can lead to better understanding of the anatomical abnormalities found in the different CHD types and thus facilitate preoperative planning and choice of the most appropriate management for adult patients. The basic principles for improved results of total hip replacement in patients with CHD, especially those with low and high dislocation, are: Wide exposure, restoration of the normal centre of rotation and the use of special techniques and implants for the reconstruction of the acetabulum and femur. Application of these principles during total hip replacement in young female patients born with severe deformities of the hip joint has led to radical improvement of their quality of life.

Biomechanical comparison of oblique and step-cut osteotomies used in total hip arthroplasty with femoral shortening

BACKGROUND

Various types of shortening osteotomies and prosthesis are used for femoral reconstruction in total hip arthroplasty of the high hip dislocation. This biomechanical study investigates whether step-cut osteotomies result in better stability than oblique osteotomies and cylindrical femoral stems enhance stability of the osteotomy more than conical stems, and which osteotomy and prosthesis type maintain the stability better after cyclical loading.

METHODS

Oblique and step-cut shortening osteotomies were compared under axial and rotational forces, using synthetic femur models and conical or cylindrical femoral prostheses. The models underwent cyclic loading for 10,000 cycles at 3 Hz (100-1000 N axial bending or 0.5-10 Nm torque). After the completion of cyclic loading, the models were loaded until failure. Stiffness values before and after cyclical loading, and failure loads were the outcome parameters. Relative displacements at the osteotomy sites were also measured using 3-Dimensions Digital Imaging Correlation System.

RESULTS

The mean failure load was significantly higher in conical prosthesis groups under axial forces. In torsion tests, the mean stiffness of conical prosthesis groups after cyclical loading was higher in oblique osteotomies. The other parameters were similar between the groups.

CONCLUSIONS

According to the results of the study, although some individual statistically significant parameters were obtained, step-cut osteotomies, which are technically challenging procedures, were not found biomechanically superior to oblique osteotomies, with neither conical nor cylindrical prostheses.

Acetabuloplasty at the anatomic centre for treating Crowe class III and IV developmental hip dysplasia: a case series

INTRODUCTION

Total hip replacement in patients with developmental dysplasia of the hip (DDH) is a difficult technical procedure for surgeons to perform because of the potential for these patients to have severe anomalies in their bones and soft tissues.

MATERIALS AND METHODS

We performed acetabuloplasty in 54 hips from 44 patients by reaming the posterior wall of the native acetabulum and medialising the acetabular component to restore the anatomic centre of hip rotation using a small cup without bone grafting. Median time to post-surgery follow-up was 5 (range 2-14) years.

RESULTS

Prosthetic survival rates in patients after 2 and 5 years post hip replacement were 93% (50/54) and 89% (48/54), respectively. 4 patients required early revision because of malposition and instability of the acetabular cup. 3 patients with Crowe type IV dislocations had transient sciatic nerve palsy and 3 had deep vein thrombosis.

CONCLUSIONS

Placement of the acetabular shell using posterior bone stock to provide normal hip rotation is a successful alternative technique for acetabuloplasty in patients with DDH.

Posterosuperior Placement of a Standard-Sized Cup at the True Acetabulum in Acetabular Reconstruction of Developmental Dysplasia of the Hip With High Dislocation

BACKGROUND

We sought to evaluate posterosuperior placement of the acetabular component at the true acetabulum during acetabular reconstruction in patients with Crowe type-IV developmental dysplasia of the hip.

METHODS

Using pelvic computed tomography and image processing, we developed a two-dimensional mapping technique to demonstrate the distribution of preoperative three-dimensional cup coverage at the true acetabulum, determined the postoperative location of the acetabular cup, and calculated postoperative three-dimensional coverage for 16 Crowe type-IV dysplastic hips in 14 patients with a mean age of 52 years (33-78 years) who underwent total hip arthroplasty. Mean follow-up was 6.3 years (5.5-7.3 years).

RESULTS

On preoperative mapping, the maximum three-dimensional coverage using a 44-mm cup was 87.31% (77.36%-98.14%). Mapping enabled the successful replacement of 16 hips using a mean cup size of 44.13 mm (42-46 mm) with posterosuperior placement of the cup. Early weight-bearing and no prosthesis revision or loosening during follow-up were achieved in all patients. The postoperative two-dimensional coverage on anteroposterior radiographs and three-dimensional coverage were 96.15% (89.49%-100%) and 83.42% (71.81%-98.50%), respectively.

CONCLUSION

This technique may improve long-term implant survival in patients with Crowe-IV developmental dysplasia of the hip undergoing total hip arthroplasty by allowing the use of durable bearings, increasing host bone coverage, ensuring initial stability, and restoring the normal hip center.

The Effect of Dislocation Type (Crowe Types I-IV) on Pelvic Development in Developmental Dysplasia of the Hip: A Radiologic Study of Anatomy

Classification of hip pathology in developmental dysplasia of the hip (DDH) helps in appropriate placement of implants during total hip arthroplasty. We examined preoperative unilateral and bilateral pelvic radiographs of 57 patients (114 hips) undergoing total hip arthroplasty because of DDH. Both sides of the pelvis were visually separated into 3 areas for comparison. When area ratios of hips with Crowe types II, III, and IV DDH were compared with ratios for healthy hips, values in hips with DDH were significantly low for the iliac wings, significantly high for the acetabular regions, and significantly low for the ischial area. Using a line crossing the healthy hip's teardrop and parallel to a line joining the distal sacroiliac joints is useful for calculating limb-length discrepancy.

THA following deformities due to congenital dislocation of the hip joint

Total hip replacement is the treatment of choice for the patient suffering from end-stage hip osteoarthritis. Excellent long-term results have been published. In the presence of deformities due to congenital hip dislocation, total hip replacement is, in most of the cases, a difficult task, since the technique of performing such an operation is demanding and the results could vary. This paper presents our experience and preferred strategies focusing on challenges and surgical techniques associated with reconstructing the dysplastic hip.

Effect of preoperative limb-length discrepancy on abductor strength after total hip arthroplasty in patients with developmental dysplasia of the hip

BACKGROUND

Limb-length discrepancy (LLD) arising from hip subluxation or dislocation and accompanied by insufficiency of hip abductor in patients with developmental dysplasia of the hip (DDH) can be corrected partially or completely with total hip arthroplasty (THA). However, information about post-THA changes in abductor strength related to preoperative LLD in patients with DDH is lacking. We aimed to explore the post-THA recovery course of abductor muscle strength and its related factors in patients with DDH.

METHODS

A cohort of 45 patients with unilateral DDH was divided into two groups according to their Crowe classification: patients with class I or II DDH formed Group M, and patients in class III and IV DDH formed Group S. The following parameters were measured on standardized antero-posterior hip radiographs taken in the supine position pre- and post-THA: abductor muscle length, abductor lever arm, LLD, and femoral offset (FO). Abductor strength was evaluated quantitatively with the Isomed 2000 isokinetic test system (1 week before the operation and 1, 3, 6, and 12 months after the operation). The contralateral normal hip joint served as a within-patient control. The affected side:healthy side ratios of the parameters above were calculated.

RESULTS

Abductor strength ratio evaluated at the five follow-up time points was larger in Group M than that in Group S (p < 0.001). The average abductor strength ratio reached 78.5, 85.4, and 89.2% at the 3, 6, and 12 months postoperative exams, respectively, in Group M, and reached 50.3, 63.2, and 72.9% in Group S. The abductor muscle length ratio, the abductor muscle level arm ratio, and the FO ratio were significantly increased postoperatively, relative to preoperative assessment, in the two groups. LLD was reduced significantly postoperatively, relative to preoperative values, in both groups. Both preoperative LLD (r = -0.791, p < 0.001) and the change in abductor muscle length ratio (r = -0.659, p < 0.001) correlated with abductor strength recovery.

CONCLUSION

Patients showed the greatest improvement in abductor strength within the first 6 months after THA, especially during the first 3 months. Abductor strength was consistently greater in patients with mild dysplasia than in patients with severe dysplasia. The extent of preoperative LLD and the increase in abductor length were related with post-THA abductor strength recovery in patients with DDH.

Ionizing radiation doses during lower limb torsion and anteversion measurements by EOS stereoradiography and computed tomography

OBJECTIVES

To calculate and compare the doses of ionizing radiation delivered to the organs by computed tomography (CT) and stereoradiography (SR) during measurements of lower limb torsion and anteversion.

MATERIALS AND METHODS

A Rando anthropomorphic phantom (Alderson RANDO phantom, Alderson Research Laboratories Inc., Stanford, Conn) was used for the dose measurements. The doses were delivered by a Somatom 16-slice CT-scanner (Siemens, Erlangen) and an EOS stereoradiography unit (EOS-Imaging, Paris) according to the manufacturers' acquisition protocols. Doses to the surface and deeper layers were calculated with thermoluminiscent GR207P dosimeters. Dose uncertainties were evaluated and assessed at 6% at k=2 (that is, two standard deviations).

RESULTS

The absorbed doses for the principal organs assessed were as follows: for the ovaries, 0.1 mGy to the right ovary and 0.5 mGy to the left ovary with SR versus 1.3 mGy and 1.1 mGy with CT, respectively; testes, 0.3 mGy on the right and 0.4 mGy on the left with SR versus 8.5 mGy and 8.4 mGy with CT; knees, 0.4 mGy to the right knee and 0.8 mGy to the left knee with SR versus 11 mGy and 10.4 mGy with CT; ankles, 0.5 mGy to the right ankle and 0.8 mGy to the left with SR versus 15 mGy with CT.

CONCLUSION

The SR system delivered substantially lower doses of ionizing radiation doses than CT to all the organs studied: CT doses were 4.1 times higher to the ovaries, 24 times higher for the testicles, and 13-30 times higher for the knees and ankles. The use of the SR system to study the torsion of lower limbs makes it possible to reduce the amount of medical irradiation that patients accumulate.

Acetabular reconstruction in patients with low and high dislocation: 20- to 32-year survival of an impaction grafting technique (named cotyloplasty)

We report the results at a mean of 24.3 years (20 to 32) of 61 previously reported consecutive total hip replacements carried out on 44 patients with severe congenital hip disease, performed with reconstruction of the acetabulum with an impaction grafting technique known as cotyloplasty. The mean age of the patients at operation was 46.7 years (23 to 68) and all were women. The patients were followed post-operatively for a mean of 24.3 years (20 to 32), using the Merle d'Aubigné and Postel scoring system as modified by Charnley, and with serial radiographs. At the time of the latest follow-up, 28 acetabular components had been revised because of aseptic loosening at a mean of 15.9 years (6 to 26), and one at 40 days after surgery because of repeated dislocations. The overall survival rate for aseptic failure of the acetabular component at ten years was 93.1% (95% confidence interval (CI) 86.5 to 96.7) when 53 hips were at risk, and at 23 years was 56.1% (95% CI 49.4 to 62.8), when 22 hips remained at risk. These long-term results are considered satisfactory for the reconstruction of an acetabulum presenting with inadequate bone stock and circumferential segmental defects.

Results of total hip arthroplasty differ in subtypes of high dislocation

BACKGROUND

In a previous study, we described two subtypes of high dislocation of the hip depending on the presence (C1) or absence (C2) of a false acetabulum, yet we have already presented the concise followup of total hip arthroplasty (THA) in these patients as a group at a minimum of 15 years.

QUESTIONS/PURPOSES

In this retrospective study, we investigated differences in the results of THA in the C1 and C2 subtypes of high dislocation such as (1) survivorship of the reconstructions; (2) Merle d'Aubigné-Postel clinical scores; (3) leg lengthening and femoral shortening; and (4) site of reattachment and union rate of the greater trochanter.

METHODS

We included 49 hips of the C1 subtype and 30 hips of the C2 subtype operated on from 1976 to 1994. We evaluated survivorship (using reoperation for any reason as the end point) and performed chart and radiographic reviews.

RESULTS

The 15-year survival was 84% (± 10% [95% CI]) for the C1 subtype and 60% (± 17% [95% CI]) for the C2 subtype (p = 0.001). Cox regression analysis, after adjustment for confounding factors, showed also statistically significantly worse survivorship in the C2 subtype (p = 0.021) and, after adjustment for possible predictive factors, found a statistically significant relationship of high dislocation subtype (p = 0.018) and trochanteric union (p = 0.005) with survival of THAs. Pain, function, and mobility scores improved from preoperative to last followup in C1 and C2 groups but they did not differ between C1 and C2 hips. C2 hips were lengthened more (p < 0.001) despite greater amounts of femoral shortening (p = 0.006). Site of reattachment and the risk of greater trochanter nonunion were not different between the groups.

CONCLUSIONS

We found important differences in fundamental parameters after THA in the high-dislocation subtypes, including the risk of revision, which was higher in patients whose hips did not have a false acetabulum. These findings indicate that while reporting THA results in patients with high dislocation, mixing results of the two subtypes may lead to statistical bias.

The ratio of femoral head diameter to pelvic height in the normal hips of a Chinese population

OBJECTIVE

The aim of this study was to determine whether the ratio between the femoral head diameter and pelvic height in a Chinese population is the same as that found in Westerners.

MATERIALS AND METHODS

Standard pelvic radiography was performed on a group of 187 Chinese adult subjects consisting of 81 males and 106 females with a mean age of 40 years (21-68 years). Femoral head diameter (vertical distance from the femoral head-neck junction to the highest point of the femoral head) and pelvic height (vertical distance from the highest point of the iliac crest to the edge of the ischial tuberosities) were measured.

RESULTS

There were significant differences between males and females (p < 0.001), and between persons of high height versus low height (p = 0.011) and medium height (p = 0.039). There were no significant differences between persons of different age (p = 0.244), body mass index (p = 0.091), or between persons of low- and medium-height groups (p = 0.69). The overall mean ratio between the femoral head diameter and pelvic height was 0.215 (0.173-0.249) with a 95 % CI = 0.214-0.217. The mean ratios in males and females were 0.221 (0.194-0.249) and 0.211 (0.173-0.238), respectively.

CONCLUSION

The mean ratio in Chinese population was similar to the reported ratio in a western population (about 1:5). We suggest that Chinese surgeons may be able to use the Crowe classification to classify patients with hip dysplasia.

Total hip arthroplasty in young females with congenital dislocation of the hip, radically improves their long-term quality of life

Eighty-two female patients with low dislocation (67 hips) or high dislocation (48 hips) were assessed using clinical scores and EQ-5D quality of life (QoL) questionnaire. Assessment was performed at the first to secondyear postoperatively and at the final follow-up, after a minimum of 12 years (12-37). Patients reported with a high EQ-5D health state VAS scale, VAS index and TTO index at 1 to 2 years follow-up (94,21/0,907/0,931) that remained considerably high despite the long-term follow-up (73,8/0,721/0,746). The scores for pain and range of motion presented with a statistically significant improvement at 1 to 2 years postoperatively and at the time of final follow-up. Function scores have declined with age. Total hip arthroplasty in CHD patients radically improves QoL for a long period of time.

Greater trochanter osteotomy with cementless THA for Crowe type IV DDH

This study explored the surgical method and short-term clinical effect of a greater trochanter osteotomy along with cementless artificial total hip arthroplasty in the treatment of Crowe type IV developmental dysplasia of the hip. The authors conducted a retrospective analysis of 18 patients (22 hips) with Crowe type IV dysplasia who were seen between June 2008 and August 2010. After undergoing cementless artificial total hip arthroplasty using a posterolateral approach, a greater trochanter osteotomy was used to adjust the tension of the gluteal muscle, and an acetabular cup was placed. Average preoperative length shortening of the affected limb was 4.5 cm (range, 3.4-6 cm), and average postoperative length increase was 4.0 cm (range, 3.2-4.8 cm). Average postoperative Harris Hip Score was 87 (range, 79-91), which was higher than the average preoperative score of 38 (range, 32-51). Intraoperatively, 3 hips (3 patients) sustained a proximal femur fracture. Due to the stability of the femoral prosthesis, either no treatment or wire fixation only was given; by 2 months postoperatively, radiographs indicated that all fractures had healed. One patient had symptoms of sciatic nerve paralysis that resolved 3 months postoperatively. Performing a greater trochanter osteotomy after cementless artificial total hip arthroplasty is effective for the treatment of Crowe type IV dysplasia and can rebuild the complex biology and biomechanics of hip dysplasia without increasing the complication risk.

Inter- and intraobserver reliability of the Crowe and Hartofilakidis classifications in the assessment of developmental dysplasia of the hip in adult patients

BACKGROUND

The purpose of this study is to investigate the inter- and intraobserver reliability of Crowe and Hartofilakidis classifications in the assessment of developmental dysplasia of the hip in adult patients.

MATERIALS AND METHODS

Two consultant orthopedic surgeons classified 141 dysplastic hips on 103 standard anterior-posterior pelvis radiographs according to the Crowe and Hartofilakidis classifications. Assessments were performed in random order by each observer on two separate occasions, at least 4 weeks apart. Kappa statistics were used to establish a relative level of agreement between observers for the two readings and between separate readings by the same observer.

RESULTS

At the first readings, interobserver reliability analysis revealed kappa coefficient of 0.71 for the Crowe classification and 0.54 for the Hartofilakidis classification. At the second reading, the kappa coefficient was 0.72 for the Crowe classification and 0.75 for the Hartofilakidis classification. Intraobserver reliability analysis revealed kappa coefficients of 0.71 for the Crowe and 0.80 for the Hartofilakidis classification for observer A, and 0.76 and 0.70 for observer B.

CONCLUSIONS

In conclusion, we have found substantial inter- and intraobserver agreement for Crowe classification and substantial to moderate agreement for Hartofilakidis classification in this study. Both classification systems assess the different aspects of developmental dysplasia of hip in adults. Each system has advantages and disadvantages. We suggest using both of these classifications together to increase the accuracy.

The twenty-year survivorship of two CDH stems with different design features

Previous studies have shown that anatomical abnormalities of the femur in dislocated hips require the application of special CDH prosthesis for the reconstruction of the proximal femur in total hip arthroplasty (THA). We have retrospectively examined the clinical records and radiographs of 50 patients (67 hips) with low and high dislocations treated with THA in our institution, between January 1987 and December 1994. For the reconstruction of the femur, the stainless steel Charnley CDH stem, with polished surface, monoblock and collarless, was used in 32 hips; the Harris CDH stem, made of CoCr, precoated at the proximal part, modular and with collar was used in 35 hips. At the time of the latest follow-up, 11 Charnley and 6 Harris CDH stems had been revised for aseptic loosening at an average of 14 years (range 6-20) and 13 years (range 2-19), respectively. The survival rate at 20 years, with failure for aseptic loosening as the end point, was 63% for the Charnley and 78% for the Harris CDH stems. These results provide a basis for evaluation of newer techniques and designs.

LEVEL OF EVIDENCE

Therapeutic study, Level IV.

Total hip arthroplasty for Crowe type Ⅳ developmental dysplasia

The purposes of this study were to evaluate the midterm clinical and radiographic results of total hip arthroplasty (THA) in patients with Crowe type IV developmental dysplasia and to evaluate whether low back pain would improve after THA. Eighteen consecutive patients (20 hips) were included in this study. The average age at the time of surgery was 58.5 years. The average follow-up was 10.2 years. The socket was placed at the level of the true acetabulum, and a femoral shortening osteotomy was performed. The average Harris hip score before surgery was improved from 56 to 85 points at the final follow-up. Revision was performed in 4 hips due to loosening of the femoral component in 1 hip and osteolysis in 3 hips. The midterm outcomes of THA in patients with Crowe type IV developmental dysplasia were satisfactory. The severity of low back pain was significantly reduced after THA.

Resurfacing arthroplasty for hip dysplasia: a prospective randomised study

In this prospective study a total of 80 consecutive Chinese patients with Crowe type I or II developmental dysplasia of the hip were randomly assigned for hip resurfacing arthroplasty (HRA) or total hip replacement (THR). Three patients assigned to HRA were converted to THR, and three HRA patients and two THR patients were lost to follow-up. This left a total of 34 patients (37 hips) who underwent HRA and 38 (39 hips) who underwent THR. The mean follow-up was 59.4 months (52 to 70) in the HRA group and 60.6 months (50 to 72) in the THR group. There was no failure of the prosthesis in either group. Flexion of the hip was significantly better after HRA, but there was no difference in the mean post-operative Harris hip scores between the groups. The mean size of the acetabular component in the HRA group was significantly larger than in the THR group (49.5 mm vs 46.1 mm, p = 0.001). There was no difference in the mean abduction angle of the acetabular component between the two groups. Although the patients in this series had risk factors for failure after HRA, such as low body weight, small femoral heads and dysplasia, the clinical results of resurfacing in those with Crowe type I or II hip dysplasia were satisfactory. Patients in the HRA group had a better range of movement, although neck-cup impingement was observed. However, more acetabular bone was sacrificed in HRA patients, and it is unclear whether this will have an adverse effect in the long term.

[Shortening osteotomy for alloarthoplastic joint replacement for hip dislocation in adults]

OBJECTIVE

Total hip arthroplasty to create an articulating hip joint. Acetabular cup implantation in the original rotational center of the pelvis. Simultaneous femoral shortening osteotomy to prevent neurovascular damage and equalize leg length in patients with unilateral occurrence.

INDICATIONS

Developmental dysplasia of the hip (DDH) in adults; type 3 and 4 dislocation according to Crowe.

CONTRAINDICATIONS

Cerebrospinal dysfunction with permanent restriction of coordination ability, muscular dystrophies, and multiple malformations of the musculoskeletal system. Apparent disturbance of the bone metabolism.

SURGICAL TECHNIQUE

The Watson-Jones interval approach to the hip joint is used to avoid functional disorders of the hip abductors. After preparation of the proximal femur and femoral neck resection, adjustment of the non-regularly developed acetabular cavity with reduced anterior coverage takes place. The cup component is implanted and the interval between the vastus intermedius and the vastus lateralis below the lesser trochanter examined. Loss of periosteum of the femoral cortex due to blunt spreading is to be avoided. Following the femoral shortening osteotomy initially the preparation of the distal bone segment takes place to adjust the endofemoral canal for shaft implantation in the following preparation of the metaphyseal segment. Afterwards osteotomy-bridging implantation of a cementless, distal anchoring stem design is performed.

POSTOPERATIVE MANAGEMENT

Partial weight bearing of the leg with 20 kp is necessary for 6 weeks combined with therapy of existing contractures and active pelvic rotation training. Within 10 postoperative weeks full weight bearing is usually reached. After this period mobilization without crutches is possible. Inpatient rehabilitation is possible after bony recovery of the femoral osteotomy.

RESULTS

From 1993 to 1999, the first 15 total hip arthroplasties were performed in adult patients with DDH; they were treated with simultaneous femoral shortening osteotomy and without additive osteosynthesis. During the midterm follow-up (4.3 years), no failure of the femoral component was observed with complication-free osseous healing of the osteotomy. One cup revision was necessary in this period. The Merle d'Aubigné score increased from 8.2 preoperatively to 15.5 points.

15-year comparison of cementless total hip arthroplasty with anatomical or high cup placement for Crowe I to III hip dysplasia

This study compared radiological and clinical results of Mallory-Head (Biomet, Warsaw, Indiana) cementless total hip arthroplasty (THA) by anatomical (AP group) or high cup placement (HP group) for Crowe I to III developmental dysplasia of the hip. Of the 68 hips studied, 43 hips were available for 15.3-year follow-up. Ten cups were placed at anatomical center with bulk bone grafting, and 33 cups were at high hip center without bulk bone grafting. No acetabular or femoral components showed loosening in either group. One standard polyethylene liner in a highly placed cup was revised due to excessive wear after 11 years. The average rate of polyethylene wear was 0.128 mm/year in the AP group and 0.148 mm/year in the HP group (except for the revision case). The extent of grafted bone coverage was 34.6% in the AP group. Hip center height was 24.5 mm from the inter-teardrop line in the HP group. The center of the hip horizontal location in the AP group (24.5 mm) and HP group (26.4 mm) was significantly shorter than in normal hips (35.6 mm). Postoperative center-edge angle was 11° (except grafted bone) in the AP group and 25° in the HP group. Mean Harris Hip Score in the AP group improved from 38 points preoperatively to 82 points postoperatively and in the HP group improved from 40 points preoperatively to 88 points postoperatively. Survivorship was 100% in the AP group and 97% in the HP group. Our results indicate that moderate high cup placement without bulk bone grafting at a horizontal locus more medial than that of a normal hip is an alternative durable solution.

The 15° face-changing acetabular component for treatment of osteoarthritis secondary to developmental dysplasia of the hip

We report the use of a 15° face-changing cementless acetabular component in patients undergoing total hip replacement for osteoarthritis secondary to developmental dysplasia of the hip. The rationale behind its design and the surgical technique used for its implantation are described. It is distinctly different from a standard cementless hemispherical component as it is designed to position the bearing surface at the optimal angle of inclination, that is, < 45°, while maximising the cover of the component by host bone.

Total hip arthroplasty in developmental hip dysplasia using cementless tapered stem. Results after a minimum 10-year follow-up

Acetabular and femoral abnormalities make total hip arthroplasty in developmental hip dysplasia a challenging procedure. We present details of long-term follow-up of a series of patients affected by developmental hip dysplasia treated with total hip arthroplasty using a cementless tapered stem. Thirty-five hips in 20 patients (18 women and 2 men) aged between 44 and 60 years (mean 51 years) were observed. Clinical evaluation was conducted using the Harris Hip Score (HHS). Radiographic evaluation consisted in standard anteroposterior and axial view radiographs of the hip. According to Crowe's classification, 25 hips had grade 2 and 10 hips grade 3 dysplasia. All patients were treated with total hip arthroplasty using a cementless tapered stem (Wagner Cone Prosthesis™). After surgery the patients were clinically and radiographically evaluated at 1, 2, 3, 6 and 12 months and annually thereafter. The average follow-up was 12 years (range 10-14 years). The average HHS was 57±7 (range 45-66) preoperatively, 90±7 (range 81-100) 12 months after surgery and 90±6 (range 83-100) at last follow-up. Radiographic evaluation demonstrated excellent osseointegration of the implants in most cases. Signs of bone resorption were present in 5 hips, but no evidence of loosening was observed and none of the implants have been revised. The tapered stem achieved adequate stability and orientation, and may be a suitable option for total hip arthroplasty for arthritis following developmental hip dysplasia.

Congenital hip dysplasia treated by total hip arthroplasty using cementless tapered stem in patients younger than 50 years old: results after 12-years follow-up

BACKGROUND

Congenital hip dysplasia may lead to severe acetabular and femoral abnormalities that can make total hip arthroplasty a challenging procedure. We assessed a series of patients affected by developmental hip dysplasia treated with total hip arthroplasty using cementless tapered stem and here we report the outcomes at long-term follow-up.

MATERIALS AND METHODS

Twenty-eight patients (24 women and 4 men) aged between 44 and 50 years (mean 47 years) were observed. Clinical evaluation was rated with the Harris Hip Score. Radiographic evaluation consisted in standard anteroposterior and axial view radiographs of the hip. According to Crowe's classification, 16 hips presented dysplasia grade 1, 14 grade 2, and 4 grade 3. All patients were treated with total hip arthroplasty using a cementless tapered stem (Wagner Cone Prosthesis). Six patients were operated bilaterally, with a totally of 34 hips operated. After surgery, the patients were clinically and radiographically checked at 3, 6, and 12 months and yearly thereafter until an average follow-up of 12 years (range 10-14 years).

RESULTS

Average Harris Hip Score was 56 ± 9 (range 45-69) preoperatively, 90 ± 9 (range 81-100) 12 months after surgery, and 91 ± 8 (range 83-100) at last follow-up. Radiographic evaluation demonstrated excellent osteointegration of the implants. Signs of bone resorption were present in 6 hips, nevertheless no evidence of loosening was observed and none of the implants has been revised.

CONCLUSIONS

Even in dysplasic femur, the tapered stem allowed adequate stability and orientation of the implant. We consider tapered stem a suitable option for total hip arthroplasty in developmental hip dysplasia, also in case of young patients, thanks to the favourable long-term results.

[Total hip replacement in developmental dysplasia: anatomical features and technical pitfalls]

Total hip arthroplasty is the procedure of choice for most patients with advanced, symptomatic osteoarthritis due to congenital dysplasia of the hip. However, the complexity of arthroplasty is significantly increased because of anatomic abnormalities associated with dysplasia of the hip. In addition the relatively young age of patients may affect survival of the implant. From a biomechanical standpoint the primary surgical objective is reconstruction of the anatomical center of rotation. Independent of the pelvic bone stock the socket should be located as near as possible to the anatomical acetabular location. There are various operative strategies to ascertain sufficient stability of the socket. The anterolateral deficiency of the acetabulum can be reconstructed by bulk femoral autografting or bone impaction grafting. Furthermore controlled perforation of the medial wall or implantation of reinforcement rings and oval sockets have been described. Cementless, biological socket fixation shows superior long-term results compared to cemented cups, especially in these young patients. The location of the reconstructed acetabulum and the desired leg length influence the type of femoral reconstruction and in some cases femoral shortening is required. In this article endoprosthetic reconstructive options for developmental dysplasia of the hip are discussed depending on the femoral and acetabular deformity.

Total hip replacement for high dislocated hips without femoral shortening osteotomy

When performing total hip replacement (THR) in high dislocated hips, the presence of soft-tissue contractures means that most surgeons prefer to use a femoral shortening osteotomy in order to avoid the risk of neurovascular damage. However, this technique will sacrifice femoral length and reduce the extent of any leg-length equalisation. We report our experience of 74 THRs performed between 2000 and 2008 in 65 patients with a high dislocated hip without a femoral shortening osteotomy. The mean age of the patients was 55 years (46 to 72) and the mean follow-up was 42 months (12 to 78). All implants were cementless except for one resurfacing hip implant. We attempted to place the acetabular component in the anatomical position in each hip. The mean Harris hip score improved from 53 points (34 to 74) pre-operatively to 86 points (78 to 95) at final follow-up. The mean radiologically determined leg lengthening was 42 mm (30 to 66), and the mean leg-length discrepancy decreased from 36 mm (5 to 56) pre-operatively to 8.5 mm (0 to 18) postoperatively. Although there were four (5%) post-operative femoral nerve palsies, three had fully resolved by six months after the operation. No loosening of the implant was observed, and no dislocations or infections were encountered. Total hip replacement without a femoral shortening osteotomy proved to be a safe and effective surgical treatment for high dislocated hips.