Concern About Femoral Neck Fractures in Long-Necked Modular Implants.

Abstract

As outlined in our January 16, 2013 editorial, “The Case Report Redefined with JBJS Case Connector ,” one important role of JBJS Case Connector is to alert the orthopaedic community about a potentially problematic device or therapy. When two or more such cases with similar mechanisms appear, we will identify the procedure or implant as a “watchable” intervention. While this system is not statistically conclusive and may or may not be supported by other published case reports or registry data, the intention is to sharpen the focus of clinicians on the potential for similar problems and thereby enhance clinical outcomes and patient safety. The “Watch” designation may also encourage others to report related difficulties and enlist the orthopaedic community to either demonstrate that these are isolated, unrelated cases or sharpen the focus further on rigorously evaluating the intervention. Where appropriate, we may identify brand, model, or implant-lot specifics. Modularity in the heads and stems of total hip prostheses has afforded orthopaedic surgeons the ability to intraoperatively adjust version, limb length, and offset in ways that can optimize hip biomechanics. Modular implants have achieved these important objectives in thousands of patients over the last couple of decades. However, the rewards of modularity come with risks—some of them serious. Reports of these risks seem to have become more prevalent in the recent orthopaedic literature. In this “Watch,” we bring to the attention of the orthopaedic community several femoral neck fractures in patients with implants that had modular head-neck and neck-stem designs. While some of these designs are no longer available from manufacturers, thousands of such devices have already been implanted. This “Watch” encourages surgeons to be wary about one specific aspect of modular hip designs: long femoral necks. One of the weakest points in any hip prosthesis is the femoral neck. This …