Computed Tomographic Evaluation of Bone Stock in Patients With Crowe Type III Developmental Dysplasia of the Hip: Implications for Guiding Acetabular Component Placement Using the High Hip Center Technique

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.

Biomechanical analysis and clinical observation of 3D-printed acetabular prosthesis for the acetabular reconstruction of total hip arthroplasty in Crowe III hip dysplasia

Objective: This study aimed to evaluate the biomechanical effectiveness of 3D-printed integrated acetabular prosthesis (IAP) and modular acetabular prosthesis (MAP) in reconstructing the acetabulum for patients with Crowe III developmental dysplasia of the hip (DDH). The results of this study can provide a theoretical foundation for the treatment of Crowe III DDH in total hip arthroplasty (THA). Methods: Finite element (FE) analysis models were created to reconstruct Crowe III DDH acetabular defects using IAP and MAP. The contact stress and relative micromotion between the acetabular prosthesis and the host bone were analyzed by gradually loading in three increments (210 N, 2100 N, and 4200 N). In addition, five patients with Crowe III DDH who underwent IAP acetabular reconstruction were observed. Results: At the same load, the peak values of IAP contact stress and relative micromotion were lower than those of MAP acetabular reconstruction. Under jogging load, the MAP metal augment's peak stress exceeded porous tantalum yield strength, and the risk of prosthesis fracture was higher. The peak stress in the bone interface in contact with the MAP during walking and jogging was higher than that in the cancellous bone, while that of IAP was higher than that of the cancellous bone only under jogging load, so the risk of MAP cancellous bone failure was greater. Under jogging load, the relative micromotion of the MAP reconstruction acetabular implant was 45.2 μm, which was not conducive to bone growth, while under three different loads, the relative micromotion of the IAP acetabular implant was 1.5-11.2 μm, all <40 μm, which was beneficial to bone growth. Five patients with IAP acetabular reconstruction were followed up for 11.8 ± 3.4 months, and the Harris score of the last follow-up was 85.4 ± 5.5. The imaging results showed good stability of all prostheses with no adverse conditions observed. Conclusion: Compared with acetabular reconstruction with MAP, IAP has a lower risk of loosening and fracture, as well as a better long-term stability. The application of IAP is an ideal acetabular reconstruction method for Crowe III DDH.

The Role of Global Femoral Offset in Total Hip Arthroplasty with High Hip Center Technique

OBJECTIVE

The high hip center (HHC) technique has been proposed for the treatment of patients with developmental dysplaisa of the hip (DDH) who have an acetabular bone defect. However, the importance of global femoral offset (FO) in the application of this technique has not been sufficiently appreciated. Our goals were to confirm that the HHC technique is feasible in the treatment of patients with DDH and to assess the function of global FO in this procedure.

METHODS

We retrospectively analyzed 73 patients who underwent total hip arthroplasty using high hip center technique for unilateral DDH at our hospital between January 2014 and June 2019. According to global FO, the patients were split into three groups: increased FO group (increment greater than 5 mm), restored FO group (restoration within 5 mm) and decreased FO group (reduction greater than 5 mm). Patients' medical records and plain radiographs were reviewed. One-way ANOVA was used to compare radiographic outcomes and Harris hip score (HHS). Paired t-test was used to assess preoperative and postoperative HHS and leg length discrepancy. Trochanteric pain syndrome, Trendelenburg sign and postoperative limp was evaluated with Fisher's exact test.

RESULTS

The average follow-up time was 7.5 ± 1.4 years. The patients' HHS and leg length discrepancy were significantly improved (p < 0.05). In terms of vertical acetabular height, abductor arm, postoperative leg length difference, and acetabular cup inclination, there was no statistically significant difference between the three groups. At the last follow-up, HHS was significantly higher in the restored FO group than in the decreased FO and increased FO groups. Trochanteric pain syndrome occurred in 15.0% and Trendelenburg sign and postoperative limp in 8.2% of all patients, respectively. Trochanteric pain syndrome, Trendelenburg sign and postoperative limp did not differ significantly across the three groups. One patient in increased FO group underwent revision for dislocation 6 years after surgery.

CONCLUSION

The HHC technique is an alternative technique for total hip arthroplasty in patients with acetabular bone abnormalities, according to the results of the mid-term follow-up. Also, controlling the correction of the global femoral offset to within 5 mm may lead to better clinical outcomes.

Acetabular Revision Arthroplasty Based on 3-Dimensional Reconstruction Technology Using Jumbo Cups

Background: This study was aimed at evaluating the changes in cup coverage (CC) and hip center of rotation (HCOR) in acetabular defects of various severities treated with acetabular revision using jumbo cups.

Methods: A total of 86 hips were included. The American Academy of Orthopedic Surgeons (AAOS) classification of these patients was as follows: 16 patients, AAOS I; 16 patients, AAOS II; and 16 patients, AAOS III. A three-dimensional (3D) implant simulation technique was used to visualize the placement of jumbo cups during revision arthroplasty. The acetabular anteversion, inclination, CC, and the HCOR were measured.

Results: The inclination and anteversion of simulated acetabular cups in AAOS I–III groups were consistent with the normal acetabular anatomy. Compared with the controls, in AAOS I–III groups, the HCOR was significantly increased and CC was significantly decreased. The HCOR elevation was significantly higher in AAOS III patients than in AAOS I (p = 0.001) and AAOS II patients (p < 0.001). The use of the jumbo cup technology for acetabular revision would decrease the CC in AAOS I–III patients to 86.47, 84.78, and 74.51%, respectively.

Conclusion: Our study demonstrated that in patients with acetabular defects, acetabular revision arthroplasty using jumbo cups will lead to decreased CC and HCOR upshift. Upon classifying these patients according to the AAOS classification, CC decreased with the severity of acetabular defects, and the elevation of the HCOR in AAOS III patients exceeded 10 mm and was significantly higher than in other patients.

Does total hip arthroplasty with high hip centre in dysplasia compromise acetabular bone stock?

BACKGROUND

The placement of uncemented acetabular components during total hip arthroplasty (THA) in Crowe II and Crowe III dysplasia can be at the anatomic or high hip centre position.

PURPOSES

Using computerised tomography data, we simulated acetabular cup placement at the anatomic hip centre and the high hip centre positions to assess whether there is a difference between the 2 in terms of bone loss from acetabular reaming and in acetabular coverage by host bone.

METHODS

The study population included a consecutive cohort of 19 patients (22 hips) with Crowe II or III dysplasia. 3-dimensional models of the pelvis were created for each patient and digital templating was used to determine the anatomic and high hip centre positions. The coordinates of the digitally templated cup positions were fed into an image processing software to estimate the amount of bone reamed, the cup coverage by host bone and the elevation from tear drop.

RESULTS

The mean volume of bone reamed was greater in the high hip centre position as compared to the anatomic position (27.3 ± 11. 4 cm³ vs. 19.4 ± 12.2 cm³, p < 0.0001). The coverage of the acetabular cup by host bone was greater in the high hip centre position (87.3 ± 5.9% vs. 68.3 ± 10%). The mean elevation in the high hip centre group was 13 mm with 3 hips having a breach of the medial wall.

CONCLUSIONS

In Crowe II and III dysplasia, placement of acetabular cups at the anatomic hip centre better preserves bone stock as compared to high hip centre placement and should be preferred in young patients requiring THA.

Bone defect map of the true acetabulum in hip dysplasia (Crowe type II and III) based on three-dimensional image reconstruction analysis

The high hip center technique (HHC) is considered to be feasible for acetabular reconstruction in patients with DDH, but there is little in-depth study of its specific impact on Crowe type II and III DDH. The purpose of this study was to simultaneously analyze the effect of HHC on bone coverage of the cup (CC) in the acetabular reconstruction of type II and III DDH patients and to propose a map of acetabular bone defects from the perspective of the cup. Forty-nine hip CT data of 39 patients with DDH (Crowe type II and III) were collected to simulate acetabular reconstruction by cup models of different sizes (diameter 38mm–50 mm, 2 mm increment) with the HHC technique. The frequency distribution was plotted by overlapping the portions of the 44 mm cups that were not covered by the host bone. The mean CC of cups with sizes of 38 mm, 40 mm, 42 mm, 44 mm, 46 mm, 48 mm, and 50 mm at the true acetabula were 77.85%, 76.71%, 75.73%, 74.56%, 73.68%, 72.51%, and 71.75%, respectively, and the maximum CC increments were 21.24%, 21.58%, 20.86%, 20.04%, 18.62%, 17.18%, and 15.42% (P < 0.001), respectively, after the cups were elevated from the true acetabula. The bone defect map shows that 95% of type II and III DDH acetabula had posterosuperior bone defects, and approximately 60% were located outside the force line of the hip joint. Acetabular cups can meet a CC of more than 70% at the true acetabulum, and approximately 60% of Crowe type II and III DDH patients can obtain satisfactory CC at the true acetabulum by using a 44-mm cup without additional operations.

Does robotic assisted technology improve the accuracy of acetabular component positioning in patients with DDH?

BACKGROUND

Accurate positioning of the acetabular component is key in performing total hip arthroplasty (THA). However, reconstruction of the acetabulum in the setting of developmental dysplasia of the hip (DDH) is a challenge. Robotic assisted THA has the potential to improve the accuracy of implantation of the acetabular cup in cases with DDH. The purpose of this study was to assess whether robotic technology improves the accuracy of acetabular component positioning in patients with DDH.

MATERIAL AND METHODS

We included 59 THAs using robotic assisted technology from June 2019 to January 2020 as the study group. These were compared to conventional THAs without robotic technology after control for age, gender, body mass index (BMI), Crowe type and operation date. Radiographic measurements were taken by 2 blinded orthopaedic residents. The percentage of hips within the Lewinnek and Collanan safe zones were calculated, along with acetabular rotation centers for the "target zone." Surgical time and perioperative bleeding were also compared between both groups.

RESULTS

One patient suffered dislocation in conventional group while no dislocation occurred in robotic group. The acetabular components of the robotic assisted group had more cases located within the Lewinnek (p = 0.013) and Collanan (p = 0.008) safe zones than conventional group (94.9% vs 79.7% and 74.6% vs 50.8%). There were 7 cases in conventional group and 4 cases in robotic group that had more lateral or more superior rotational centers of THA, but did not reach statistical significance (p = 0.342). No statistical difference was detected between groups with regards to blood loss (p = 0.098) and surgical time (p = 0.602).

CONCLUSION

Robot assisted technology can assist surgeons with implanting acetabular cups more in Lewinnek and Callanan safe zone than conventional techniques without additional blood loss and surgical time.

LEVEL OF EVIDENCE

Therapeutic Level Ⅲ.

Diagnosis, preoperative evaluation, classification and total hip arthroplasty in patients with long-term unreduced hip joint dislocation, secondary osteoarthritis and pseudoarthrosis

Background

Neglected long-term unreduced hip joint dislocation with secondary osteoarthritis and pseudoarthrosis poses a great challenge to hip surgeons. However, as this is an uncommon injury, few studies have systematically investigated these patients.

Methods

We retrospectively reviewed 16 patients from 2010 to 2017. The diagnostic values of three different types of common radiological examinations were evaluated. We evaluated the bone conditions of the original acetabulum and classified the patients into three types (four subtypes). The surgical procedures and prognosis of the patients were also investigated.

Results

With the combined application of X-ray, CT scans and 3D reconstruction, 93.8% of these patients (sensitivity = 93.8%, Youden’s index = 0.93, intraclass correlation coefficient = 0.95) could be diagnosed correctly. There were 6/16 (37.5%) type A patients, 4/16 (25.0%) type B1 patients, 5/16 (31.3%) type B2 patients and 1/16 (6.3%) type C patient. For patients with type A injury, the surgical procedures for total hip arthroplasty were similar to “standard” total hip arthroplasty. For patients with type B injury, due to atrophy or partial bone deficiency of the original acetabulum, the surgical procedure for total hip arthroplasty was probably similar to those for patients with developmental dysplasia of the hip. For patients with type C injury, the situation was similar to that of revision surgery. The average Harris hip score postoperatively was 89.94 ± 5.78 points (range: 79–98 points).

Conclusions

The new classification system could help surgeons estimate potential difficulties during total hip arthroplasty. The prognosis of most patients after total hip arthroplasty is expected to be excellent or good.

Novel 3D printed integral customized acetabular prosthesis for anatomical rotation center restoration in hip arthroplasty for developmental dysplasia of the hip crowe type III: A Case Report

RATIONALE

Exact restoration of the rotation center in total hip arthroplasty (THA) is technically challenging in patients with end-stage osteoarthritis due to developmental dysplasia of the hip (DDH), especially in the Crowe type II and III procedures. The technical difficulty is attributable to the complex acetabular changes. In this study, a novel 3-dimensional (3D) printed integral customized acetabular prosthesis for anatomical rotation restoration in THA for DDH Crowe type III was developed using patient-specific Computer-aided design and additive manufacturing (AM) methods.

PATIENT CONCERNS

A 69-year-old female patient had developed left hip joint pain and restricted movement for 40 years; the symptoms had increased in the past 5 months. Pain, limited motion of the left hip joint, and lower limb length discrepancy were noted during physical examination.

DIAGNOSIS

The patient was diagnosed with left hip end-stage osteoarthritis secondary to DDH (Crowe type III).

INTERVENTION

A 3D printed acetabulum model was manufactured and a simulated operation was performed to improve the accuracy of reconstruction of the rotation center and bone defect. A 3D printed titanium alloy integral customized acetabular prosthesis was designed according to the result of simulated operation. The integral customized prothesis was implanted subsequently via the posterolateral approach. Radiography of the pelvis and Harris score assessment were performed during the perioperative period as well as at the 6- and 12-month follow-up.

OUTCOMES

The 3D printed integral customized acetabular prosthesis matched precisely with the reamed acetabulum. The rotation center was restored and the bone defect was exactly reconstructed. There were no signs of prosthetic loosening at the 12-month follow-up. The Harris score gradually improved during the follow-up period.

LESSONS

Satisfactory results of hip rotation restoration and bone defect reconstruction could be achieved by using 3D printed integral customized acetabular prosthesis, which provides a promising way to reconstruct the acetabulum in patients with DDH anatomically and rapidly for THA.

Assessment of pelvic morphology using 3D imaging and analysis in unilateral Crowe-IV developmental dysplasia of the hip

AIMS

Morphological abnormalities are present in patients with developmental dysplasia of the hip (DDH). We studied and compared the pelvic anatomy and morphology between the affected hemipelvis with the unaffected side in patients with unilateral Crowe type IV DDH using 3D imaging and analysis.

METHODS

A total of 20 patients with unilateral Crowe-IV DDH were included in the study. The contralateral side was considered normal in all patients. A coordinate system based on the sacral base (SB) in a reconstructed pelvic model was established. The pelvic orientations (tilt, rotation, and obliquity) of the affected side were assessed by establishing a virtual anterior pelvic plane (APP). The bilateral coordinates of the anterior superior iliac spine (ASIS) and the centres of hip rotation were established, and parameters concerning size and volume were compared for both sides of the pelvis.

RESULTS

The ASIS on the dislocated side was located inferiorly and anteriorly compared to the healthy side (coordinates on the y-axis and z-axis; p = 0.001; p = 0.031). The centre of hip rotation on the dislocated side was located inferiorly and medially compared to the healthy side (coordinates on the x-axis and the y-axis; p < 0.001; p = 0.003). The affected hemipelvis tilted anteriorly in the sagittal plane (mean 8.05° (SD 3.57°)), anteriorly rotated in the transverse plane (mean 3.31° (SD 1.41°)), and tilted obliquely and caudally in the coronal plane (mean 2.04° (SD 0.81°)) relative to the healthy hemipelvis. The affected hemipelvis was significantly smaller in the length, width, height, and volume than the healthy counterpart. (p = 0.014; p = 0.009; p = 0.035; p = 0.002).

CONCLUSION

Asymmetric abnormalities were identified on the affected hemipelvis in patients with the unilateral Crowe-IV DDH using 3D imaging techniques. Improved understanding of the morphological changes may influence the positioning of the acetabular component at THA. Acetabular component malpositioning errors caused by anterior tilt of the affected hemi pelvis and the abnormal position of the affected side centre of rotation should be considered by orthopaedic surgeons when undertaking THA in patients with Crowe-IV DDH. Cite this article: Bone Joint J 2020;102-B(10):1311-1318.

Preoperative Planning for Total Hip Arthroplasty for Neglected Developmental Dysplasia of the Hip

Developmental dysplasia of the hip (DDH) is accompanied by morphological alterations on both the acetabular and the femoral side. Total hip arthroplasty (THA) provides effective treatment in cases of neglected DDH but requires elaborate preoperative planning. To determine the morphological changes resulting from the dysplasia, the anatomic acetabular position, the height of the femur head dislocation, the height of the femur head dislocation, and the combined anteversion must all be established. In addition, a vital and complicated process of strategizing leg length balance must be conducted in cases of severe DDH. Each type of leg length discrepancy (LLD), including bony and functional and anatomical LLD, should be evaluated in the context of the presence or absence of a fixed pelvic tilt. Moreover, with severe unilateral dislocated hips, a more inferior change in the original rotational center of the hip must be accounted for. Due to these multiple morphological changes, the accurate size of the prosthesis and the cup position are difficult to predict. In comparison with other methods, CT scan‐based 3‐dimensional templating provides the best accuracy. Despite the presence of anatomic alterations, various types of acetabular and femoral prostheses have been developed to treat hip dysplasia. Both cemented and cementless cups are used in DDH cases. In DDH accompanied by insufficient acetabular bone stock, a cemented cup combined with bone graft provides a reliable treatment. Monoblock stems can be used when the combined anteversion is less than 55°, and a modular stem system when this parameter is greater than 55°. Customized stems can be designed for DDH coupled with severe proximal femoral distortion. A ceramic‐on‐ceramic bearing is considered optimal for young DDH patients.