Impact of Prior Periacetabular Osteotomy on Total Hip Arthroplasty Outcomes in Patients with Developmental Dysplasia of the Hip

<b>Background:</b> This study aims to demonstrate the challenges during the treatment of patients with osteoarthritis due to the development of dysplasia, which can be faced by surgeons who treat patients with THA. Our objective is to present our findings from a comparison of patients who underwent total hip arthroplasty (THA) for osteoarthritis secondary to developmental dysplasia of the hip (DDH), with or without a prior periacetabular osteotomy (PAO). <b>Methods:</b> We divided patients into two groups. Group A was adolescents who underwent periacetabular osteotomy and further THA in the orthopedic center (29 hips), and Group B was adolescents who underwent THA without PAO but suffered from DDH (24 hips). We measured blood loss, cup size, cup positioning, cup coverage, inclination and anteversion of the cup, duration of surgery, clinical scores, time of hospitalization, and the presence of ossification. <b>Results:</b> The mHHS score demonstrated significant differences (group A: 89 points vs. group B: 91 points; <i>p</i> = 0.03). The blood loss was expressed in the difference in Hb concentration preoperatively and on the 3rd postoperative day, which was higher by 0.85 mg/dL in group A (group A: 4.4 mg/dl vs. group B: 3.55 mg/dL; <i>p</i> = 0.004). Also, the value of HCT on the 3rd postoperative day was significantly lower in group A (group A: 27% vs. group B: 29.5%; <i>p</i> = 0.02). Radiological measurements showed a statistically significant difference in the Brooker scale (<i>p</i> = 0.005). Thirteen patients from group A after THA expressed first-grade ossifications or higher, and two patients from group B had first- and second-grade ossifications. Furthermore, a notably larger distalization was observed after the PAO procedure compared to those who underwent the procedure without PAO previously (79 mm [IQR = 73-83 mm] vs. 74.5 mm [IQR = 69-77 mm]; <i>p</i> = 0.004). Conclusions: Patients reported lower mHHS results, a higher risk of heterotopic ossifications, prosthesis head distalization, and more significant blood loss during the perioperative period after THA in patients who underwent PAO compared to those without a previously performed osteotomy.