Background: Children who present late with developmental dysplasia of the hip (DDH) often require pelvic osteotomy to achieve adequate femoral head coverage and long-term hip stability. Standard Salter osteotomy (SO) is a well-established procedure; however, modified Salter osteotomy (MSO) has been introduced to improve acetabular orientation and radiographic coverage.

Objective: To compare MSO and standard SO regarding clinical and radiological outcomes in children presenting late with DDH at intermediate-term follow-up.

Methods: This prospective comparative study included 15 children/18 hips with late-presenting DDH who randomly underwent either MSO or standard SO. The study was performed at the Orthopedic Department of the Children Welfare Teaching Hospital, Medical City Complex, Baghdad, during the period from April 1 to December 6, 2022. Clinical evaluation was performed using the McKay criteria and gait assessment. Radiological evaluation included measuring the acetabular index (AI) preoperatively and postoperatively, while the centre-edge angle (CEA) was measured at the 3-year follow-up. All patients were followed up for a minimum of three years.

Results: The two groups were comparable in terms of McKay grading, gait pattern, and hip stability. Radiologically, the MSO group demonstrated significantly better outcomes: AI improved from 33.7±5.72 to postoperatively 17.6±3.44, while in the SO AI improved from 35.1±4.75 to postoperatively 20.3±3.8 , CEA in SO 26.9±5.26, while in MSO was 30.8± 4.65°. No re-dislocation was observed during the follow-up period.

Conclusion: Both modified and standard Salter osteotomies are safe and effective procedures for treating late-presenting DDH. However, the modified Salter osteotomy provides superior radiological correction, as demonstrated by improved acetabular parameters, while achieving clinical outcomes comparable to those of standard Salter osteotomy.