JBJS Classics: The Self-Locking Metal Hip Prosthesis

JBJS ClassicsOrthoBuzz regularly brings you a current commentary on a “classic” article from The Journal of Bone & Joint Surgery. These articles have been selected by the Editor-in-Chief and Deputy Editors of The Journal because of their long-standing significance to the orthopaedic community and the many citations they receive in the literature. Our OrthoBuzz commentators highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation about these classics by clicking on the “Leave a Comment” button in the box to the left.

Austin Moore’s article “The Self-Locking Metal Hip Prosthesis” was published in The Journal of Bone & Joint Surgery in 1957. Dr. Moore had a lifelong professional interest in hip-fracture surgery and was well aware of the problems associated with reduction and fixation of displaced femoral neck fractures. He had previously designed an internal-fixation device for the management of these injuries and had recognized that perfect reduction, accurate placement of the hip nail, and 100% compliance with non-weight bearing were prerequisites for a satisfactory outcome. For patients in whom those criteria could not be met or those in whom reduction and fixation had failed, an alternate method of managing these fractures was required.

Fourteen years prior to the publication of this landmark article, Dr. Moore had published a case report in The Journal (July 1943) in which he documented the use of a metal prosthesis to replace the proximal end of the femur for a patient with an aggressive giant cell tumour. Some years later the patient succumbed from other causes and the femur was retrieved at autopsy. The specimens demonstrated satisfactory osseointegration of this implant in the proximal femur and encouraged Dr. Moore to experiment with a number of models of proximal femoral implants. This progression of implant design and usage is carefully outlined in this classic paper, which is amply illustrated with radiographs and autopsy specimens of the evolving prosthesis that eventually became known as the Austin Moore hip prosthesis.

This paper is notable for a number of reasons. First, Dr. Moore was able to demonstrate satisfactory fixation using an intramedullary stemmed implant—a significant departure from the early efforts of the Judet brothers and others, who used a small stem in the residual femoral neck in patients being treated for hip arthritis. Secondly, the author developed a specific surgical approach allowing for the insertion of these slightly curved stems into the femur—an approach that is still used today in a number of surgical hip procedures.

Third, Dr. Moore demonstrated the usefulness of proximal femoral replacement in acute displaced femoral neck fractures, avascular necrosis following femoral neck fracture, and non-unions of the femoral neck. He further expanded the use of this implant in the treatment of hip arthritis and documents a number of such cases in this article.

Throughout the article, Dr. Moore emphasizes the importance of meticulous surgical technique, the use of bone ingrowth fixation, careful sizing of the femoral head to the native acetabulum, and the importance of conscientious post-operative care. Finally, he recognized the importance of routine follow-up of endoprostheses and insisted on a yearly visit to ensure appropriate integration of the prosthesis.

In summary, with this article Dr. Moore started a trend of endoprosthetic treatment for displaced femoral neck fractures that is now the standard of care throughout much of the world. During the development of this technique, he demonstrated the importance of bone ingrowth as a method of stabilizing the prosthesis, the importance of good surgical technique, and the value of long-term follow-up in managing patients with hip prostheses. The fact that the implant he designed and reported on 60 years ago is still in widespread use is a reflection of his vision.

James P. Waddell MD, FRCSC
JBJS Deputy Editor

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