Olecranon osteotomy(Chevron) Müller described an extraarticular osteotomy to involve primarily the triceps attachment. The most popular variation of the olecranon osteotomy to date is that of the Chevron osteotomy. In this approach, a V type of osteotomy is created at the mid portion of the olecranon through the region not covered by hyaline cartilage. The osteotomy is fixed with a screw or tension band fixation. The two disadvantages of olecranon osteotomy are the (low) risk of nonunion and the fact that the anconeus must be transected and denervated in order to reflect the olecranon and the extensor mechanism proximally. This causes atrophy of the anconeus and it is no longer available for some of the other reconstructive options. Olecranon osteotomy is attractive in its simplicity and remains one of the most popular exposures to the elbow worldwide, particularly for the purpose of managing fractures. Consider performing a subcutaneous transposition of the ulna nerve. (Ulna nerve decompression)
IndicationExposure of the distal humeral articular surface can be achieved by:
Osteotomy of the olecranon is particularly valuable in the treatment of comminuted distal fractures of the humerus involving the articular surface. HOWEVER, this increases the complexity of the procedure and has its own complications. It cannot be used for total elbow arthroplasty since this requires an intact ulna for the fixation of the distal component of the prosthesis. Consider techniques in which the triceps is split or reflected as these can be used for fixation of fractures and for total elbow arthroplasty, but they give a less satisfactory exposure of the distal humerus than can be achieved by olecranon osteotomy.
Consider triceps split +- refection
Anatomy
ConsiderationsConsider Tourniquet high on arm
PositioningSupine with arm over L bar or Lateral with arm over L bar so forearm hanging freely
Skin IncisionPosterior incision beginning proximal to the olecranon, extend distally, skirting the radial or ulnar aspect of the tip of the olecranon, and continue along the subcutaneous border of the ulna 4 cm distal to the olecranon. Consider
skirting radially and lifting skin flap (takes scar away from area under
pressure when resting arm on table etc.) Superficial dissection
Decompress the ulnar nerve by releasing the fascia of the flexor carpi ulnaris for 4 to 6 cm in line with the ulnar nerve to allow nerve mobility during fracture manipulation and fracture fixation. If plate fixation is anticipated in the region of the cubital tunnel, consider anterior ulnar nerve transposition.
Deep dissectionPredrill and tap the olecranon and ulna shaft if you plan to repair the osteotomy with a screw, alternatively use 2 K-wires and tension band wiring at the end of the procedure.
At a point approximately 2 to 3 cm from the tip of the olecranon, a single K-wire is passed to the subchondral bone perpendicular to the ulna at the level of the extraarticular portion of the olecranon fossa. This position is confirmed by elevating 5 to 7 mm of the anconeus laterally and the flexor carpi ulnaris medially with a Freer elevator. The K-wire serves as a focal point for a distally oriented chevron osteotomy. The osteotomy is performed with an oscillating saw to the level of the subchondral bone. Complete the osteotomy with an
osteotome. As the triceps is elevated proximally, the intercondylar/supracondylar portion of the distal humerus is fully exposed.
Exposure extensionProximal extensionExposure is limited to the midshaft of the humerus, specifically in the locale of the radial nerve.
Archdeacon described an olecranon osteotomy in association with a modified triceps splitting approach to complete the exposure of the proximal and midshaft of the humerus. The interval between the lateral and long heads of the triceps is palpitated, and blunt finger dissection separates the proximal interval between the long and lateral heads of the triceps. As the blunt dissection is carried distally, the more adherent fascia over the deep head of the triceps requires sharp incision. The radial nerve and profundus brachi artery are just proximal to the deep head of the triceps, and care should be taken to protect these structures. The dissection is continued distally using a combination of blunt and sharp dissection through the raphe of the triceps, exposing the posterior mid and distal shaft of the humerus. The median and ulnar nerves are protected within the medial triceps mass, and the radial nerve and profundus artery are protected in the lateral triceps mass as the triceps split is carried distally to within 2 to 3 cm of the triceps insertion on the olecranon. This wide posterior exposure allows excellent access to the shaft of the humerus. Working between the two intervals of the olecranon osteotomy and the posterior triceps split, allows complete exposure of the midshaft and supracondylar/intercondylar humerus.
ClosureThe olecranon is repaired with 2 * (2mm) K wires and tension band wiring (18Gauge) or a 6.5mm partially threaded screw.
Post operatively
References
Archdeacon, Michael T. Combined Olecranon Osteotomy and Posterior Triceps Splitting Approach for Complex Fractures of the Distal Humerus. Journal of Orthopaedic Trauma. 17(5):368-373, May 2003.
Page created by: Lee Van RensburgLast updated 11/09/2015 |