Abstract
Introduction: The Opera Acetabular cup (Smith and nephew) was designed in North Manchester General and has been in use since 1997. The initial results were with multiple surgeons, different approaches and 2 different stems. We report the early results of the opera cup in primary hip replacements using the C-Stem.
Methods: This is a prospective radiological follow up of patients operated on between June 2000 and November 2004. 202 consecutive primary hip replacements were carried out using the Opera cup and a standard C-stem. All operations were performed by a single surgeon using the posterior approach. Initial and annual x-rays were studied and the following measurements taken: cup angle; radiolucent lines in the bone-cement interface of the acetabulum; heterotopic ossification; radiolucent lines or osteolysis in the femoral component and stem orientation.
Results: Full data is available in 166 hips performed on 149 patients. Average follow up is 37 months (12–65). 84 patients were female and 65 male. There were 56 left hip replacements, 76 right hip replacements and 17 were bilateral. 162 hips had an elite head whereas 4 had a ceramic head. Average cup angle was 44.6 degrees. 20 Cups had 0.5mm lucency in zone 1 of the acetabulum and 1 cup had 1mm lucency in zone 1. None were progressive. 14 patients had grade 1 heterotopic ossification 3 patients had grade 2. 1 stem was in valgus and 13 stems were in varus.
Complications were 1 calcar fracture and 1 greater trochanter fracture (both of which required circlage wires). There was also 1 temporary femoral nerve palsy which resolved in 3 months. There were no fatal PE’s, deep infections or dislocations. No hips have required revision.
Discussion: We conclude that in the short term the Opera cup is performing to the standard required by NICE.
Correspondence should be addressed to The Secretary, BHS, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.
