The Locking Nail for the Humerus - Does it Fulfill the Expectations?

Abstract

IntroductionThe humeral shaft fracture constitutes only 1 to 5 % of all human fractures [57,68,82]. Most of the time it concerns simple fracture patterns, type A or B according to the AO classification. In less then 18 % C-type fractures are found. Less then 6 % are open fractures [28,82,89,128]. In the above 50s, 80 % of humeral shaft fractures are caused by a simple fall [7]. Combined with the lower anatomical demands for the humerus, this makes it the ideal bone for non-operative treatment (Fig. 1). The Sarmiento brace allows early use of shoulder and elbow joint and can be considered the standard for treatment of humeral shaft fractures [37,61,67,71,77,92,110,112,137,138,142]. Despite good results, high failure rates up to 41 % have been reported after non-operative treatment as well [27,48]. Some circumstances therefore will request operative treatment of humeral shaft fractures. These include failure to maintain reposition, neurovascular lesion, floating elbow, (impending) pathologic fractures, open fractures, poly-trauma, non-union and uncooperative patients. The golden standard for operative treatment of the humerus has been the plate (Fig. 2) for a long time leading to high union rates [4, 8, 9,32,33,58,59,60,87,91,130,141] ( Table 1). The most important point of criticism has been the large incisions with soft tissue damage enhancing the risk for non-union and infection. For a long time the only alternative technique for the plate were the elastic nails like bundle nailing and rush pins. Minimal invasive techniques, indirect reposition of the fracture preserving the fracture haematoma and less soft tissue damage are the main advantages. Good healing results have been reported with non-union rates of 1.2 up till 6.8 % [21, 25, 27,34,35,38,47]. Disadvantages are the lesser rotational and axial stability of the constructs. Early functional treatment therefore is not always possible.An interlocking nail combines the minimal invasive technique with the rotational and axial stability of a plate. Seidel introduced the Humeral Locking Nail ® (SN) (Fig. 3). Good healing results with non-union rates of 0 up to 4 %. have been reported. AbstractThe purpose of this article is to evaluate the humeral locking nail in the treatment of humeral shaft fractures. First disappointing experiences with reamed locking nails led at least to some controversy. A review of the literature on treatment of humeral fractures showed that he majority of (clinical) information was contained in retrospective reviews; only three prospective or randomized studies were identified. Furthermore the results are not consistent. The criticism based on experiences with first implants is not entirely justified. The humeral locking nail is a valid implant for the treatment of humeral fractures. Like every other implant however it comes with its own specific complications and there is a learning curve. The humeral locking nail therefore should be seen as a complementary technique to the existing implants with its own advantages and drawbacks.