Acetabular configuration and its impact on cup coverage of a subtype of Crowe type 4 DDH with bi-pseudoacetabulum

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.

Anatomical Parameters Associated with the Shortening Decision in Crowe Type 4 Dysplastic Hip Osteoarthritis: A Case-Control Study

Background

Muscle and bone morphometry may be potent indicators for predicting femoral subtrochanteric shortening osteotomy (FSSO). We aimed to investigate muscular and bony factors that may be predictive of FSSO.

Methods

Patients with unilateral Crowe type 4 developmental dysplasia of the hip (DDH) who underwent unilateral total hip arthroplasty (THA) without (Group 1, 31 patients) and with FSSO (Group 2, 39 patients) were included. Sixty healthy hips (Group 3) were selected as the control group. Several muscular and bony parameters were measured on the operative (O) and non-operative (NO) hips on radiographs and computed tomography (CT) images.

Results

The mean NO gluteus medius cross-sectional area (CSA) index (NO-GMed CI), NO tensor fasia lata (TFL) CI, NO iliopsoas (IP) CI, and NO gluteus maximus (GMax) CI for the control group were lower than those for both Crowe type IV DDH with and without FSSO. The mean NO gluteus minimus CI (NO-GMin CI) for the control group were higher than those for both Crowe type IV DDH with and without FSSO. There was significant difference between Groups 1 and 2 regarding axial position of neo-acetabulum (APNA) (- 0.03 ± 8.5 vs. 5.27 ± 6.33, p = 0.004), coronal position of neo-acetabulum (CPNA) (33.39 ± 10.65 vs. 53.70 ± 12.27, p = 0.000), operative leg length discrepancy (O-LLD) (14.18 ± 15.14 vs. 24.44 ± 15.80, p = 0.001), O-gluteus minimus (GMin) length (155.34 ± 157.73 vs. 106.79 ± 20, p =  < 0.01), and O-GMin CI (57.28 ± 58.59 vs. 29.95 ± 12.13, p =  < 0.01). The cutoff values determined by the receiving operating curve analyses were as follows: 13.7 mm, 2.5 mm, and 41.4 mm for O-LLD, APNA, and CPNA, respectively.

Conclusion

FSSO is associated with APNA, CPNA, O-LLD, O-GMin length, and O-GMin CI. By using cutoff values of APNA, CPNA, and O-LLD, predicting FSSO preoperatively is possible. Owing to these parameters, it may be possible to lower the technically demanding level of surgery.

Algorithm for automatic angles measurement and screening for Developmental Dysplasia of the Hip (DDH)

Developmental Dysplasia of the Hip (DDH) is a medical term represent the hip joint instability that appear mainly in infants. The examination for this condition can be done by ultrasound for children under 6 months old and by X-ray for children over 6 months old. Physician's assessment is based on certain angles derived from those images, namely the Acetabular Angle, and the Center Edge Angle. In this paper, we are presenting a novel, fully automatic algorithm for measuring the diagnostic angles of DDH from the X-ray images. Our algorithm consists of Automatic segmentation and extraction of anatomical landmarks from X-ray images. Both of Acetabular angle and Center edge angle are automatically calculated. The analysis included X-ray images for 16 children recruited for the purposed of this study. The automatically acquired angles accuracy for Acetabular Angle was around 85%, and an absolute deviation of 3.4°±3.3° compared to the physician's manually calculated angle. The results of this method are very promising for the future development of an automatic method for screening X-ray images DDH that complement and aid the physicians' manual methods.