Challenging age limits: favourable mid-term outcomes of periacetabular osteotomy in patients over 30 years of age with borderline hip dysplasia

Abstract The treatment of borderline hip dysplasia (BHD) remains controversial, with a paucity of literature on whether periacetabular osteotomy (PAO) is a viable option even in middle-aged patients over 30 years of age. This study aimed to analyse the functional outcome and activity level in relation to the patient’s age after PAO for BHD. Patients over 30 years of age (G30—age 30–40; G40 age > 40) undergoing PAO for BHD were enrolled in this single-centre study with a minimum follow-up of 2 years. The patient-reported outcomes (PRO) were assessed using the numeric rating scale (NRS) for pain, the modified Harris-Hip score (mHHS), and International Hip Outcome Tool-12 (iHot-12) for joint functionality, and the University of California Los Angeles activity score (UCLA) for sports participation. Forty-eight patients (48 hips) were included. There was a significant postoperative pain relief in both groups (G30 pre-post 7.2 - 2.7, P < .001; G40 pre-post 7.3 - 2.5, P < .001). Joint functionality improved postoperatively with significant higher scores for mHHS (G30 pre-post 48.0 - 80.0, P < .001; G40 pre-post 44.9 - 84.4, P < .001) and iHot-12 (G30 pre-post 40.1 - 68.8, P < .001; G40 pre-post 41.5 - 64.9, P = .004) for patients older than 30 and 40 years. Sports participation only improved significantly after PAO in patients older than 40 years (pre-post 5.4 - 6.9, P = .019). Overall, PAO is a viable option to treat BHD in middle-aged patients, while improving pain and joint function. Even patients over 40 years of age can benefit in terms of activity and joint function.