Developmental dysplasia of the hip (DDH) presents a unique set of anatomical hurdles for orthopedic surgeons. Performing THA for DDH femoral reconstruction requires a sophisticated understanding of proximal femur morphology. Dysplastic femurs often exhibit excessive neck anteversion, narrow intramedullary canals, and a significant metaphyseal-diaphyseal mismatch. Consequently, these variations alter hip biomechanics and weaken the abductor mechanism. Therefore, surgeons must employ precise preoperative planning to ensure stable implant fixation and functional recovery.

Navigating Femoral Morphological Variations

Surgeons must address the high degree of femoral neck anteversion typically seen in DDH. Furthermore, the narrow canal and variable neck-shaft angles often preclude the use of standard off-the-shelf implants. Using CT-based three-dimensional planning can significantly improve the accuracy of stem sizing. Additionally, restoring the true center of rotation is vital for long-term implant survival. However, achieving this often necessitates complex surgical maneuvers, such as femoral shortening osteotomy, to prevent neurovascular stretch injuries.

Selecting the Right Implant for THA for DDH Femoral Success

Implant choice remains a critical factor in managing dysplastic femurs. While both cemented and cementless stems show positive results, specific case needs should dictate the choice. Cemented stems offer excellent version control and reduce the risk of intraoperative fractures in patients with poor bone quality. Conversely, conical fluted stems provide superior fixation in severe deformities with high anteversion. Moreover, modular stems allow for independent adjustment of the neck version and distal fit. These specialized designs help surgeons navigate the unique THA for DDH femoral anatomy, ensuring stable reconstruction even in complex high-grade cases.

The Role of Subtrochanteric Shortening Osteotomy

In cases of severe dislocation, such as Crowe IV DDH, surgeons frequently perform subtrochanteric shortening osteotomy. This technique allows the surgeon to reduce the femoral head into the true acetabulum without overstretching the sciatic nerve. Similarly, this procedure helps correct abnormal femoral version simultaneously. Research indicates that this approach leads to excellent functional outcomes and high union rates. As a result, patients experience improved gait and a significant reduction in limb-length discrepancy.

FAQs

What are the primary femoral deformities in DDH?

Common deformities include excessive femoral neck anteversion, narrow intramedullary canals, reduced offset, and a high neck-shaft angle. These factors make standard stem insertion technically demanding.

Why is a shortening osteotomy used during THA for DDH?

Surgeons use shortening osteotomies to facilitate the reduction of the femoral head into the true hip center. This prevents excessive tension on the sciatic and femoral nerves, reducing the risk of postoperative palsy.

How do conical stems help in DDH cases?

Conical fluted stems allow the surgeon to adjust the femoral version independently of the stem's distal fixation. This is particularly beneficial in femurs with high anteversion where standard stems might cause impingement or instability.

Disclaimer: This content is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Refer to the latest local and national guidelines for clinical practice.

References

Konstantinidis K et al. 'THA for DDH: replacement principles and techniques - femoral side'. EFORT Open Rev. 2026 May 01. doi: 10.1530/EOR-2026-0069. PMID: 42065226.

Castagnini F et al. Which stem in total hip arthroplasty for developmental hip dysplasia? A comparative study using a 3D CT-based software for pre-operative surgical planning. Arch Orthop Trauma Surg. 2023;143(6):3481-3489.

Atik OŞ et al. Total hip arthroplasty in the developmental dysplasia of the hip using transverse subtrochanteric osteotomy. Eklem Hastalik Cerrahisi. 2019;30(1):3-8.