[The AO/ASIF Flexnail : A flexible intramedullary nail for the treatment of humeral shaft fractures]

[Antegrade and retrograde nailing of humeral shaft fractures]

OBJECTIVE

Restoring humeral shaft alignment using direct or indirect reduction techniques with subsequent intramedullary stabilisation with an antegrade or retrograde inserted humeral nail. Achieving osseous union and restoration of painfree upper arm function.

INDICATIONS

Antegrade: Humerus shaft fractures located in the proximal 2/3 of the humerus. Combined fractures of the ipsilateral proximal humerus and humerus shaft. Segmental fractures of the humerus shaft. Pathological fractures or osteolysis (palliative indication). Retrograde: Humerus shaft fractures located in the middle and distal part of the humerus diaphysis.

CONTRAINDICATIONS

Acute infection in the area of the surgical approach; polytrauma with acute life-threatening haemodynamic instability.

SURGICAL TECHNIQUE

In the antegrade technique: anterolateral acromial approach. Determination of the correct nail entry point on the humeral head. Incision of the rotator cuff with longitudinal split of the fibres. Closed or semi-open fracture reduction. Insertion of an intramedullary nail with an appropriate length and diameter. Interfragmentary compression when required. Proximal and distal static interlocking with at least 2 bolts on each side. In the retrograde technique, the nail is inserted after opening of the medullary cavity directly proximal to the olecranon fossa.

POSTOPERATIVE MANAGEMENT

Functional aftertreatment with passive and active-assisted exercises during the first 3 weeks. Subsequent active exercises avoiding forced rotation of the arm. Sports activities and severe stress are avoided for 3 months. Postoperative radiographs as well as after 2, 6 and 12 weeks.

RESULTS

Very good healing results with excellent clinical and radiological healing are achieved in more than 90% of cases after both antegrade and retrograde nailing. Intraoperative problems that have been reported in up to 40% of cases occurred mainly with former generation nails or were attributable to technical errors. Correspondingly, with the closed reduction technique postoperative infections are rare (< 3%). Undesirable distraction at the fracture site is successfully corrected by intraoperative interfragmentary compression. Success and complication rates after intramedullary nailing and plate fixation are not significantly different. Functional shoulder-related problems may occur after antegrade nailing, whereas elbow problems may occur after retrograde nailing.

[Therapy of humeral shaft fractures]

Fractures of the humeral shaft are less frequent than those of the proximal humerus. The formerly recommended treatment of humeral shaft fractures was conservative according to Böhler. This still remains an adequate concept of treatment but according to a change in the technical possibilities and the demands of patients and physicians on fast restoration of function and low pain, there is a trend towards surgical stabilization of humeral shaft fractures. The implant of choice is discussed controversially and consists of various types of nails versus plating. The technique of nailing is antegrade or retrograde and depends on the localization of the fracture. In our opinion good indications for plating are combined fractures of the proximal humerus and the shaft as well as very distal humeral shaft fractures. A primary lesion of the radial nerve is no imperative indication for exploration and different studies have shown the same results for exploration after 2 or 3 months if there is no spontaneous remission.

Minimally Invasive Anterior Plate Osteosynthesis in Humeral Shaft Fractures

Twelve patients with shaft fractures of the humerus were treated with percutaneous anterior plate osteosynthesis using a deltoid-pectoral respectively brachialis splitting approach without exposure of the radial nerve. The implants used were PHILOS plates, locking compression plates 3.5 and 4.5, and a tibial metaphyseal plate (all by Synthes). There were no intraoperative complications, no infections and no iatrogenic injuries of the radial or axillary nerve. Nine fractures healed entirely. There was one pseudarthrosis caused by a plate that was too short; another fracture probably healed but the distal screws broke; and one patient was lost to follow-up. Minimally invasive anterior plate osteosynthesis in humeral shaft fractures is an operative alternative which may be indicated not only in delayed healing or complex shaft fractures.