Long-term Clinical and Radiological Results of Implantation of Cementless Corail Stem

Introduction

The hydroxyapatite coating is one of the widely accepted bioactive materials. Despite the promising clinical results of cementless implants with hydroxyapatite coating, concerns emerged in the 1990s regarding the degradation and delamination of the hydroxyapatite layer in the long term. Nevertheless, the clinical and radiological results of a 20-year follow-up of the Corail cementless stem implantation do not confirm these previous concerns.

Patient Cohort

A total of 320 patients who underwent 347 total hip implantations between 1986 and 1990 were included in the prospective study. All implantations were performed by one surgeon at a single orthopedic center. The average follow-up duration was 20.9 ± 1.2 years, with an average age at implantation of 63.3 years.

The collared version was more frequently used during implantations (76%) compared to the collarless version of the stem (24%). Various acetabular components were used in both cemented and uncemented forms. All procedures were performed through the anterolateral Watson-Jones approach. The most common reason for implantation was osteoarthritis (76%), followed by avascular necrosis (6%).

During the follow-up, 165 patients (51.5%) died, and another 29 (9.1%) were lost to follow-up. A total of 12 stems were extracted for various reasons.

Results

The functional results of the implantation were excellent, especially in terms of pain. A total of 83% of patients did not experience pain in the operated hip during the follow-up. In total, 61% still reported a Postel-Merle d’Aubigné score of 18, indicating essentially a normal hip joint, without pain and with full range of motion.

Radiological signs of osteointegration were observed in 82% of cases, particularly in the more distal parts of the stem. No radiolucent lines were observed in any patient, while in a minority (0.6%), reactive lines were observed in zone 1, and in a smaller portion (8%), potential granulomas were also seen, primarily in the trochanteric region. Only 2 cases of grade 3 stress shielding were reported during the follow-up. Overall, 83% of patients had no pathological findings on imaging methods, while another 15% had radiological signs at the calcar level (osteolysis and other changes) without any clinical response.

Conclusion

During the 20-year follow-up of the Corail cementless stem, excellent clinical and radiological results were demonstrated. After 20 years of implantation, the implant survival rate reached 96.8%, while the global survival rate of all arthroplasties was 83% over the same period.

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CZ-2020-09-113

Source: Vidalain J. P. Twenty-year results of the cementless Corail stem. Int Orthop 2011; 35 (2): 189–194, doi: 10.1007/s00264-010-1117-2.