RETROSPECTIVE RESULTS OF 200 THA WITH A DOUBLE MOBILITY ACETABULAR IMPLANT

Abstract

Introduction: Double mobility acetabular implant has a semicircular shape, it is covered with hydroxyapatite, the entire surface has a thickness of 3 mm and its centers of rotation are shifted.

The polyethylene employed is a high density one and it has some chanfers to avoid the cam effect.

Methods and materials: We present the results o an homogeneous series of 200 patients, operated between 2003 and 2007. Clinical and radiographic parameters were analyzed prospectively. The mean follow-up was done during 15 months. Clinical results were evaluated by the HHS at the out patients clinics: previous and post surgery.

Results: From the 200 patients operated (130 women-70 men / Mean age: 81 years old): 57,63% had a primary hip osteoarthritis; 5,77 % femoral necrosis ; 1,13 % rheumatoid arthritis; 16,95 % revision surgeries; 13,45% femoral neck fractures; 3,2% acetabular fractures y 1,5 % hip tumours.

HHS before surgery was 45, 83 points on average (from 12 to 79) y post surgery HHS was 80, 03 points (from 37 to 100), increasing the total score after the arthroplasty in a mean of 34, 17 points

Post surgery complications were as follow: 3 dislocations (1 after an enormous fall and 2 in patients with Alzheimer. In our series there are 50 patients diagnosed of dementia-Alzheimer); 1 per prosthetic fracture (revision surgery); 4 deep infections (2 acute: lavage+ antibiotherapy; 2 late ones: spacer + antibiotherapy +second time surgery); 2 Deep vein thromboses (Eco Doppler +) ; 10 urinary infections; 2 urinary retentions and 17 deaths.

Discussion: Double Mobility acetabular implant has shown good results in all the following indications: Revision surgery, hip osteoarthritis, femoral necrosis, Rheumatoid arthritis, femoral neck and acetabular fractures, hip tumours and as an implant for Computer Assisted Hip Surgery.

Conclusions: The complications founded while this acetabular implant is used appeared with the same percentage than others. The dislocation rate is lower than standard acetabular implants, especially in patients with neuromuscular or cognitive illnesses.

Those clinical results are hopeful and they could increase the number of actual indications (hip osteoarthritis in people over 70 years old, multiple illnesses associated, iterative dislocations…) for the double mobility implant on the future.