Ceramic-on-ceramic cementless total hip arthroplasty in patients aged 40 years or under: Do preoperative conditions affect long-term results?

Introduction: Underlying diseases, bone deformities and polyethylene wear affect outcome in young patients undergoing total hip arthroplasty (THA). These issues are not widely confirmed for ceramic - on ceramic THA, particularly regarding cup fixation. Therefore, we did a retrospective long-term investigation on a large population of cementless ceramic-on-ceramic THA in patients aged 40 years or younger aiming to analyze: 1) the complication rate; 2) clinical results; and 3) survival for cup loosening with regard to their preoperative conditions. Hypothesis: Cup loosening could be related to preoperative diagnosis in young patients with a cementless ceramic-on-ceramic THA. Patients and methods: Two hundred and seven hips in 171 patients (97 men and 74 women) underwent a cementless ceramic-on-ceramic THA at a mean age of 31.6 +/- 6.8 years. The most frequent diagnoses were avascular necrosis (AVN) of the femoral head (74 hips), pediatric hip diseases (35 hips), severe congenital hip dysplasia (CHD) (31 hips), juvenile rheumatoid arthritis (30 hips) and mild CHD (26 hips). The prosthesis included a press-fit metal backed cup with a hydroxyapatite coating and a macrotexture surface on either the equatorial region (93 cups) or the entire surface of the shell (114 cups). Ceramics were made of pure alumina and had a femoral head size of 28 (60 hips) or 32 mm (147 hips). In all cases same the straight cementless tapered stem was inserted. Results: There were three early dislocations, one requiring cup revision No hip was revised due to infection, ceramic fracture, or femoral component loosening. Eight cups were revised for aseptic loosening (3,8%). The mean preoperative Harris Hip score was 52.8 +/- 6.2 and 93.4 +/- 6.9 at the end of follow-up. It was better in AVN (95.7 +/- 2.3) and worst in severe CHD (88.8 +/- 11.8) (p = 0.001). If the end-point was cup aseptic loosening, the survival rate at 17 years was 95.1% (95% CI: 91.3-98.9), 100% for AVN and post-traumatic arthritis, and 86.8% (95% CI: 74.9-98.7) for severe CHD. Conclusions: Despite diagnoses frequently causing technical difficulties at the surgery, outcome of cementless ceramic-on-ceramic THA in patients under the age of 40 years is satisfactory over ten years of follow up. Cup aseptic loosening was the main cause of failure and appears more related to the initial hip diseases than the age of the patient. (C) 2021 Elsevier Masson SAS. All rights reserved.