Abstract
Introduction
Clione Anchored Replacement Prosthesis (CARP-H system) is a novel femoral implant for cementless fixation at the metaphysis of the proximal femur and preservation of cancellous bone of the femoral diaphysis is expected (Fig.1). We developed CARP-H system and started to use the prosthesis after the approval by Pharmaceuticals and Medical Devices Agency in 2012. This study examines the efficacy and short-term outcome of CARP-H system in a series of patients undergoing total hip arthroplasty (THA) or bipolar hemi-arthroplasty (BHA).
Patients and Methods
Seventeen patients (17 hips) of osteonecrosis of the femoral head (ON) or osteoarthritis of the hip (OA) were included. The diagnoses were OA in 10 patients, and ON in 7 patients. The mean age at surgery was 55 years (35–62 years). The mean follow-up was 12 months (6–19 months). THA using CARP-H system was performed in 11 hips and BHA in 6 hips.
Results
The mean clinical score with the Merle d'Aubigne and Postel system was improved from 8 points preoperatively to 16 points at follow-up. No complications such as infection, dislocation, intraoperative fracture, or pulmonary infarction were identified. No radiolucent line around the prosthesis was observed postoperatively.
Discussion and Conclusion
We used to perform THA using the thrust plate hip prosthesis (TPP) which is an outstanding prosthesis for young patients in terms of bone preservation and biological fixation. Our mid- or long-term outcome of TPP was satisfactory provided the indication was appropriate. However, TPP has been kicked out in our country since 2006. The structural concept of CARP-H system is derived from TPP, and the design of the prosthesis is modified in order to adapt to Japanese patients. CARP-H system could be a beneficial prosthesis from the viewpoint of bone-preservation at the proximal femur.
