Results of Hip Arthroplasty Using a COREN Stem at a Minimum of Ten Years

Abstract

Purpose: We report on the 10-year clinical hip function and radiologic outcomes of patients who underwent hip arthroplasty using a COREN stem.

Materials and methods: A consecutive series of 224 primary cementless hip arthroplasty implantations were performed using a COREN stem between 2009 and 2011; among these, evaluation of 128 hips was performed during a minimum follow-up period of 10 years. The mean age of patients was 65.4 years (range, 40-82 years) and the mean duration of follow-up was 10.8 years (range, 10-12 years). Evaluation of clinical hip function and radiologic implant outcomes was performed according to clinical score, thigh pain, and radiologic analysis.

Results: Dramatic improvement of the mean Harris hip score (HHS) from 59.4 preoperatively to 93.5 was observed at the final follow-up (P≤0.01). Stable fixation was demonstrated for all implants with no change in position except for one case of Vancouver type B2 periprosthetic femur fracture. A radiolucent line (RLL) was observed in 16 hips (12.5%). Thigh pain was observed in only two hips (1.6%) at the final follow-up. There were no cases of osteolysis around the stem. The survival rate for the COREN stem was 97.7%.

Conclusion: Good long-term survival with excellent clinical and radiological outcomes can be achieved using the COREN femoral stem regardless of Dorr type.

Keywords: Femur; Hip; Hip replacement arthroplasty; Prosthesis.

Fig. 1. Photograph of COREN stem (BENCOX^®; Corentec, Seoul, Korea). The stem has three vertical ribs on proximal portion; anterior, posterior, and lateral.

Fig. 2. (A) Preoperative radiography of a 73-year-old male patient suffered from femur neck fracture. (B) Immediate postoperative radiography after total hip arthroplasty shows a well-implanted prosthesis. (C) Anteroposterior radiography shows stably fixed implants with a radiolucent line in Gruen zone 1, 2, and 7 at 1 year after arthroplasty. (D) Anteroposterior radiography taken 5 years after arthroplasty demonstrates no marked changes with radiolucent lines that had not progressed. (E) Anteroposterior radiography taken 10 years after arthroplasty demonstrates no marked changes with radiolucent lines that had not progressed, and stable bony fixation of both the acetabular cup and femoral stem.

Fig. 3. Incidence of thigh pain, stress shielding, and radiolucent lines (thigh pain, P=0.125; radiolucent line, P=0.232; stress shielding, P=0.135).

Fig. 4. (A) Preoperative radiography of a 56-year-old female patient suffered from avascular necrosis of left femoral head. (B) Preoperative magnetic resonance imaging (T2-weighted image) of a same female shows avascular necrosis of left femoral head. (C) Anteroposterior radiography taken at 1 year after arthroplasty shows well-fixed implants without a radiolucent line. (D) Anteroposterior radiography taken at 5 year after arthroplasty demonstrates stably well-fixed implants without a radiolucent line. (E) Anteroposterior radiography taken 11 years after arthroplasty with well-fixed stem, no radiolucent lines, and mild stress shielding on Gruen zone 1.

Fig. 5. (A) Preoperative radiography of a 60-year-old male suffered from avascular necrosis of the femoral head. (B) Immediate postoperative radiography after total hip arthroplasty shows a well-implanted prosthesis. (C) A radiography at two years after surgery shows periprosthetic fracture (Vancouver type B2) was seen at proximal femur. (D) Immediate postoperative radiography after revision surgery shows a stable implant fixation. (E) Anteroposterior radiography taken 10 years after revision surgery demonstrates well healed previous fracture without any complications.

Fig. 6. Ten-year Kaplan–Meier survival curves using any reoperation at the end point.