BACKGROUND: Periacetabular osteotomy (PAO) is an effective treatment for preosteoarthritis and early osteoarthritis in young and active patients with hip dysplasia. However, conversion to total hip arthroplasty (THA) for failed PAO is difficult owing to morphologic changes. The objective of the present study was to investigate outcomes of patients who underwent THA for failed PAO. METHODS: We performed a case-control study. The participants were 48 patients (52 hips) who underwent THA after PAO (the osteotomy group); type of PAO was eccentric rotational acetabular osteotomy in 36 hips and rotational acetabular osteotomy in 16 hips. These patients had a mean age at surgery of 56.5 years and underwent postoperative follow-up for a mean period of 5.4 years. For the control group, after matching age, gender, and time of surgery, we included 96 patients (104 joints) who underwent primary THA for hip dysplasia. RESULTS: The 2 groups demonstrated no significant difference in the preoperative Harris Hip Score. However, the osteotomy group demonstrated a significantly poor Harris Hip Score at the last follow-up, with particularly low scores for gait and activity. The osteotomy group demonstrated significantly poor range of motion at the last follow-up. Although neither group had any cases of revision surgery, both groups had 1 case of postoperative dislocation. Considering socket placement in Lewinnek's safe zone, the osteotomy group had significantly poorer results compared to that obtained after primary THA. CONCLUSION: The therapeutic outcomes and socket positioning for THA after PAO were poorer compared to those of primary THA.
BACKGROUND: Periacetabular osteotomy (PAO) is an effective treatment for preosteoarthritis and early osteoarthritis in young and active patients with hip dysplasia. However, conversion to total hip arthroplasty (THA) for failed PAO is difficult owing to morphologic changes. The objective of the present study was to investigate outcomes of patients who underwent THA for failed PAO. METHODS: We performed a case-control study. The participants were 48 patients (52 hips) who underwent THA after PAO (the osteotomy group); type of PAO was eccentric rotational acetabular osteotomy in 36 hips and rotational acetabular osteotomy in 16 hips. These patients had a mean age at surgery of 56.5 years and underwent postoperative follow-up for a mean period of 5.4 years. For the control group, after matching age, gender, and time of surgery, we included 96 patients (104 joints) who underwent primary THA for hip dysplasia. RESULTS: The 2 groups demonstrated no significant difference in the preoperative Harris Hip Score. However, the osteotomy group demonstrated a significantly poor Harris Hip Score at the last follow-up, with particularly low scores for gait and activity. The osteotomy group demonstrated significantly poor range of motion at the last follow-up. Although neither group had any cases of revision surgery, both groups had 1 case of postoperative dislocation. Considering socket placement in Lewinnek's safe zone, the osteotomy group had significantly poorer results compared to that obtained after primary THA. CONCLUSION: The therapeutic outcomes and socket positioning for THA after PAO were poorer compared to those of primary THA.