- Email: [email protected]
THE TRICEPS-REFLECTING ANCONEUS PEDICLE (TRAP) APPROACH FOR DISTAL HUMERAL FRACTURES AND NONUNIONS
MANAGEMENT OF PROXIMAL AND DISTAL HUMERUS FRACTURES
0030-5898/00 $8.00
+ .OO
THE TRICEPS-REFLECTING ANCONEUS PEDICLE (TRAP) APPROACH FOR DISTAL HUMERAL FRACTURES AND NONUNIONS Shawn W. ODriscoll, MD, PhD, FRCS(C)
Fractures of the distal humerus can be challenging to treat, to the point of being intimidating or frustrating for the operating surgeon. One recurring topic that is a constant source of question, discussion, and controversy concerns the surgical exposure. The reasons for this controversy relate not only to the need for adequate exposure but also the prevalence of complications of the surgical exposures presently used. Olecranon osteotomy is the form of surgical exposure recommended by most experts in elbow trauma for the treatment of complex intra-articular fractures of the distal humerus6 There are good reasons for this recommendation, as discussed by Ring and Jupiter in their article on distal humeral fractures elsewhere in this issue. The principal justification is for optimal exposure. Osteotomy is not without complications, however, including nonunion, intra-articular adhesions, and arthritis. Furthermore, if total elbow arthroplasty is necessary instead of open reduction and internal fixation (ORIF), the procedure is compromised by having performed an osteotomy, and nonunion of the osteotomy is much more likely.
Finally, the olecranon osteotomy as it is currently performed denervates the anconeus muscle, which receives its innervation through a terminal branch of the radial nerve passing from proximal to distal through the triceps and into the anconeus muscle. This nerve is transected as part of the soft tissue dissection for olecranon osteotomy. Although denervation of the anconeus may not seem to be of great significance, the anconeus muscle functions as the dynamic stabilizer of the elbow, and its bulk provides a vascular muscle bed for the proximal ulna and lateral side of the elbow. The ideal surgical exposure for internal fixation of distal humerus fractures permits (1) adequate exposure, (2) extensile options, (3) soft tissue dissection without osteotomy, (4) dissection in the internervous planes and not across nerves, (5) all surgical alternative procedures to be performed through the same exposure, (6) rapid rehabilitation of the involved part, and (7) subsequent reconstructive surgery incorporating the same exposure. The triceps-reflecting anconeus pedicle (TRAP)approach described in this article fulfills these prerequisites and, to the author's knowledge,
From the Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota ~
ORTHOPEDICCLINICS OF NORTH AMERICA VOLUME 31 * NUMBER 1 *JANUARY2000
91
92
ODRISCOLL
might be the only approach for the treatment of complex, comminuted articular fractures of the distal humerus that does meet all these criteria.
SURGICAL TECHNIQUE Patient Position
The patient may be placed in the lateral decubitus position with the arm hanging free over a bolster; however, the author prefers to place the patient supine, with a bolster under the ipsilateral scapula and the arm across the chest with the humerus in a vertical position. This position has the disadvantage of requiring one extra assistant but the advantage of permitting greater versatility and maneuverability, particularly while working with the elbow fully flexed (hyperflexed). Axial traction in a distal direction encourages alignment of the fracture fragments.
Superficial Exposure
In considering exposure of the distal humerus, one should be aware that “The front door to the elbow is at the Most surgical procedurw on the elbow can be done through a universal posterior skin incision just medial or just lateral to the tip of the olecran (Fig. 1).The incision starts and finishes in the midline, but the author recommends avoiding the tip of the olecranon because of the potential for skin-wound healing problems in that region. The incision is extensile, permitting increased exposure proximally, distally, or both, and may be as short as 5 to 6 cm or as long as the entire arm and forearm in extreme circumstances. For most distal humeral fractures, a skin incision about 15 cm long is appropriate. This incision has the advantage of avoiding most branches of the cutaneous n e r ~ e s . ~ The incision is carried down to the level of the deep fascia and triceps tendon, extending medially and laterally to the supracondylar ridges (Fig. 2). The ulnar nerve is identified and dissected free of its surrounding tissues, then gently retracted. An anterior subcutaneous transposition is performed routinely un-
Figure 1. “The front door to the elbow is at the back.”l0.l1 A universal skin incision for elbow operations, includinginternal fixation of distal humeral fractures, is a longitudinal posterior incision, just lateral or just medial to the tip of the olecranon. For the triceps-reflecting anconeus pedicle (TRAP) approach for internal fixation of distal humeralfractures, the incision is usually approximately 15 cm long and is placed just lateral to the tip of the olecranon,where direct pressure on the elbow can be avoided. (By permission of the Mayo Foundation.)
less medial plating of the distal humerus is not necessary. Deep Exposure
The deep exposure involves combined approaches from the lateral and medial sides of the elbow (see Fig. 2). The sequence is unimportant because one can start with the lateral or medial approach first. The author generally starts on the lateral side, then proceeds to the medial side. Part I: Lateral Side (Modified Kocher Approach)
The lateral portion of the exposure is a modified Kocher approach (Fig. 3).9 There are
THE TRAP APPROACH FOR DISTAL HUMERAL FRACTURES AND NONUNIONS
~
93
Figure 2. A and B, The TRAP approach, incorporatinga modified Kocher approach on the lateral side and a triceps-reflectingapproach on the medial side, with the two approaches converging distally at the tip of the anconeus. Medial and lateral skin flaps are raised to expose the supercondylar ridgeson either side of the distal humerus. The ulnar nerve is identified adjacent to the triceps tissue medially in preparation for subcutaneous anterior transposition. Laterally, the flaps are elevated to expose the interval between the anconeus and the extensor carpi ulnaris (ECU). This interval is defined by a septa that is barely visible and palpable beneath the deep fascia. The internal passes from the posterior aspect of the lateral epicondyle to the subcutaneous border of the ulna approximately 10 cm distal to the olecranon. FCU = flexor carpi ulnaris muscle. (By permissionof the Mayo Foundation.)
important modifications to the traditional Kocher approach. First, the lateral collateral ligament and annular ligament are preserved intact. Second, the anconeus is elevated subperiosteally off the ulna and dissected off the capsule and lateral collateral ligament complex. Third, the origins of the common extensor tendons, extensor carpi radialis longus, and brachioradialis are left undisturbed on the humerus because no exposure is required anterior to the lateral epicondyle or supracondylar ridge of the humerus. This exposure and the development of the tissue planes are accomplished most readily starting distally and progressing proximally (see Fig. 3). The interval between the anconeus and the extensor carpi ulnaris is incised starting 10 cm distal to the olecranon and extend-
ing up toward the lateral epicondyle, then the incision is carried proximally on the supracondylar ridge (see Fig. 2). The septa between the anconeus and extensor carpi ulnaris is just barely palpable and visible. The anconeus essentially forms a triangular shape bordered by a point just posterior to the lateral epicondyle, the tip of the olecranon, and the subcutaneous border of the olecranon 10 cm distally. After the incision in the deep fascia is made, the anconeus is first dissected off the septa between it and the extensor carpi ulnaris, then subperiosteally off the ulna starting distally and working proximally toward the collateral ligament. The anconeus tendon and muscle then are dissected off the annular ligament and lateral collateral ligament complex, which are preserved, and the dissection is continued be-
94
ODRISCOLL
Figure 3.A and B, The modified Kocher approach on the lateral side, commencingdistally in the interval between the extensor carpi ulnaris (ECU) and the anconeus. The anconeus muscle is dissected off the lateral side of the elbow and proximal ulna, preserving the integrity of the lateral collateral ligament complex, including the annular ligament. This outcome is accomplishedmost easily by commencingthe dissection distally and working proximally. The muscle fibers and tendon of the anconeus are dissected off the an”nular ligament, lateral collateral ligament complex, and capsule (B, top inset). The subperiosteal dissection is continued laterally beneath the anconeus muscle to the subcutaneousborder of the ulna. The posterior capsule is incised and the dissection is carried proximally between the triceps and posterior humerus (B, bottom inset). The fibers of the deep (medial) head of the triceps are dissected off the posterior humerus by sharp and blunt dissection. (By permission of the Mayo Foundation.)
neath the triceps muscle proximally along the supracondylar ridge and posterolateral distal humerus. At the level of the tip of the olecranon, an arthrotomy is made, and the dissection is continued through the capsule at that point and around posteriorly. It is essential that the collateral ligament complex not be violated. Part II: Medial Approach
The medial exposure consists of the triceps-reflecting approach to the posterior aspect of the elbow, as described by Bryan and M ~ r r e y .Starting ~,~ 10 cm distal to the olecranon (at a point corresponding to the distalmost extent of the anconeus muscle attachment), an incision is made in the periosteum on the sub-
cutaneous border of the ulna, continuing proximally along the edge of the flexor carpi ulnaris origin (see Fig. 2). The periosteum is then elevated off the subcutaneous surface of the ulna from medial to lateral, continuing beneath the anconeus, which is elevated subperiosteally off the lateral side of the ulna (Fig. 4A and €0.At the medial side of the olecranon, the incision is extended proximally along the medial border of the triceps while retracting the ulnar nerve. The triceps is reflected laterally off the distal humerus with a scalpel, carefully releasing Sharpey’s fibers from their insertion at the tip of the olecranon (see Fig. 4A and B ) . Although the triceps inserts on most of the olecranon and continues distally as a periosteal sleeve on the proximal ulna, the critical
THE TRAP APPROACH FOR DISTAL HUMERAL FRACTURES AND NONUNIONS
95
Figure 4. A and 6,The medial triceps-reflecting approach performed by reflecting the triceps laterally off the posterior distal humerus in continuity with the periosteal sleeve over the olecranon and proximal ulna. Starting at the distal tip of the anconeus (see Fig. 2), an incision is made in the periosteumalong the edge of the ulnar origin of the flexor carpi ulnaris (FCU) muscle to the medial tip of the olecranon and then is continued proximally along the medial border of the triceps. The proximal ulna is exposed subperiosteally, then the Sharpey’s fibers at the insertion of the triceps on the tip of the olecranon are released carefully by sharp dissection. This critical portion of the exposure must be performedcarefully to maintain continuity of the triceps and periosteal sleeve. After dissecting slightly more than halfway across the tip of the olecranon, a marking suture is placed in the Sharpey’s fibers precisely where this part of the tendon is to reattach to the olecranon at the completion of the procedure (6, inset). The marking suture is essentialfor anatomic reattachmentof the triceps tendon and preventionof shortening, lengthening, or medial and lateral displacement. After the completion of the procedure it is difficult to tell precisely where the Sharpey’s fibers end in the triceps sleeve. When internal fixation of distal hurneral fractures requires a medial plate, as it frequently does, the ulnar nerve is decompressedroutinelyfrom the cubital tunnel and is transposed subcutaneouslyanteriorly. Illustration continued on followingpage
portion is an area approximately 1 cm in diameter on the oIecranon. This area is located in line with the intramedullary long axis of the ulna (i.e., where K-wires are inserted for tension band fixation of an olecranon fracture). It is important to reattach the triceps precisely at that point at the completion of the procedure, so that the proper length-tension relationship is restored and the mechanical advantage of the olecranon is not lost. A marking suture is placed in the Sharpey fibers at the time of their release (see Fig. 4B, inset). At the completion of the procedure, it is difficult to tell where that
point was without a suture marking it. Proper marking permits accurate reattachment, preventing not only shortening, but also lengthening or medial or lateral displacement of the tendon. Lengthening leaves a gap between the end of the main portion of the tendon and the bone. Lateral displacement of the tendon permits detachment of the tendon because of the lateral pull of the anconeus. The dissection on the medial side now has progressed to the point at which dissection on the lateral side had stopped, such that the planes of dissection meet proximally on the
96
(YDRISCOLL
Figure 4 (Confinued).C, The dissection is continued laterally beneath the triceps and anconeus until it joins the previous plane of dissection in the modified Kocher approach from the lateral side (noted by the location of the forceps). 0,Once the modified Kocher and triceps-reflectingapproaches have been performed medially and laterally, respectively, a continuous plane of elevationexists beneath the sleeve of tr‘iceps, anconeus, and periosteum (indicated by fingers beneath the tissues). The final step is detachment of the periosteum from the subcutaneous border of the ulna at the distal end of the anconeus (0, inset) and the reflection of the triceps proximally (see Fig. 5), as one would reflect the triceps approximately following olecranon osteotomy. (By permission of the Mayo Foundation.)
humerus beneath the triceps and distally on the ulna beneath the anconeus (Fig.4C and D). The fascia1 and periosteal attachments of the distal anconeus are released, and the entire triceps and anconeus pedicle is reflected proximally (Fig. 5). Full flexion of the elbow permits the same exposure to the distal humerus as does an olecranon osteotomy except for a small portion of the articular surface of the anterior trochlea (see Fig. 5 ) .
Triceps Reattachment
The technique for triceps reattachment is particularly important, and attention to detail is mandatov. Two crisscross drill holes are
made through the ulna from proximal to distal, beginning at the normal critical attachment site of Sharpey’s fibers on the olecranon (Fig. 6A). These holes exit distally on either side of the ulna. One or more transverse holes also are drilled. A heavy nonabsorbable suture (no. 2 or no. 5 ) is placed through the triceps precisely at the location of Sharpey’s fibers (which was marked by the marking suture during the triceps reflection earlier (Fig. 6B). The suture is woven back through again in a locking stitch, similar to a modified Mason-Allen stitch as described by Gerber et al? This stitch exits the deep surface of the triceps tendon at Sharpey’s fibers and then is passed through the drill hole with a straight needle. After exiting the ulna
THE TRAP APPROACH FOR DISTAL HUMERAL FRACTURES AND NONUNIONS
97
Figure 5. A and B, The exposure of the distal humerus provided by the TRAP approach. Full flexion of the elbow is required for maximal exposure, which is almost equivalent to that provided by olecranon osteotomy, with the exception of a portion of the anterior trochlea, which can be visualized by looking in the lateral ulnohumeral articulation while retracting the ulna gently with a blunt retractor. (By permission of the Mayo Foundation.)
distally, the suture is woven over the top of the periosteum, through the anconeus muscle, then reenters the bone distally on the opposite side of the ulna (see Fig. 6 B , left inset). After being brought out of the ulna at the attachment site of Sharpey’s fibers proximally, the suture is passed through the triceps tendon
about 1 cm away from where it had entered the tendon. These two holes, where the suture passes through the tendon, should be aligned precisely with the proximal drill holes on the ulna at the attachment site of the tendon. The suture is then pulled so that all of the slack is taken up, and the tendon is pulled down to
Figure 6. A, In preparation for reattachment of the triceps, three drill holes are made in the proximal ulna, two criss-crossing at the critical attachment site of the Sharpey’s fibers on the proximal surface of the olecranon and one transversally just distal to the other two. 6,The suture technique for reattaching the triceps. The sequence of steps (leftinset)starts with a modified Mason-Allanblockingsuture, placed precisely where the marking suture had been placed on the undersurface of the triceps tendon at the termination of Sharpey’s fibers; the heavy nonabsorbablesuture is placed through the tendon and then through the drill holes in the bone, weaving back in the opposite direction and out through the tendon. After the tendon is pulled securely down against the olecranon, the suture is tied and then is woven proximately in a Bunnell fashion to imbricate the tendon and take the tension off the reattachmentsite right at the olecranon (6,top right inset). The fascia1sleeve, including the edges of the periosteumand anconeus pedicle, are closed with a running, locking suture (6, bottom right inset). Transverse stitches also are placed through the olecranon and over the periosteumon the subcutaneousborder of the ulna. (By permission of the Mayo Foundation.)
98
THE TRAP APPROACH FOR DISTAL HUMERAL FRACTURES AND NONUNIONS
the bone by the locking suture. The suture is tied tightly. Next, the free ends of the suture are woven 3 to 5 cm proximally into the triceps tendon in a Bunnell fashion, pulled, and tied so as to reef or create some slack in the distal triceps tendon (see Fig. 6B, fop right inset). The reasons for this are twofold: First, this slack permits tension in the triceps tendon to be absorbed at the proximal suture knot and less so at the reattachment to the olecranon. This protects the reattachment and lessens micromotion between the reattached tendon and bone. Second, the knotted heavy suture material at the tip of the olecranon is a significant potential source of soft tissue irritation and has even resulted in delayed wound breakdown. This additional Bunnell stitch draws the knotted suture material back down into the tendon and prevents such irritation. Furthermore, the heavy suture requires multiple knots to prevent intying, and fewer knots can be used at the olecranon because additional security for the suture is provided through the proximal knot. Another suture is placed through the transverse hole, grabbing the periosteal sleeve on either side of the ulna. Finally, a running locking suture is used to secure the free edges of the triceps, anconeus, and periosteum (see Fig. 6B, bottom righf inset). This approach, with appropriate attention to the details of tendon reattachment, permits immediate rehabilitation with full active and passive range of motion of the elbow except extension against resistance.
DISCUSSION
Since 1990, the author has used the TRAP approach, and it has become the author’s preferred approach for treating distal humeral fractures and nonunions in which intra-articular comminution is sufficient to require extensive exposure of the joint surfaces. Although the integrity of the triceps has not been specifically investigated, there have been no apparent cases of triceps detachment that the author has recognized in 20 patients treated in this manner. A number of other triceps detachment approaches have been reported, although the frequency of complications with
99
the triceps tendon has not been well documented.3,13,15 A stepwise decision-making approach should be used in exposing these fractures. The reader may recognize that the full extent of this extensile approach need not be employed in all cases. One can expose the supracondylar columns and distal humerus on either side of the triceps without detaching the triceps tendon in cases of noncomminuted or extra-articular distal humeral fractures. This situation is similar to that described by Alonso-Llames’ and Pierce and Herndon.12For minimally comminuted intra-articular fractures, the anconeus can be left attached distally and partially reflected with the triceps, which has been detached from its olecranon insertion, either medially2 or laterally.I4Leaving a sleeve of anconeus and periosteum attached to the ulna provides additional assurance of triceps integrity after repair. The advantages of this approach include not only its versatility, as part of an overall extensile approach, but also the fact that it meets the other criteria stated earlier for an ideal surgical approach. It is through soft tissues and not bone, via internervous planes, which permits all surgical options and later reconstructive procedures (such as total elbow arthroplasty) to be performed through one approach. On reexploration of patients who have had an olecranon osteotomy, the anconeus muscle has been noted to have atrophied to the point of nonexistence. The anconeus provides dynamic stability on the lateral side of the elbow, preventing varus or posterolateral rotatory instability. Although the function of this muscle has not been well understood, it would be advantageous to avoid its denervation. The anconeus also provides a vascular bed of soft tissue for protecting the lateral side of the elbow. The innervation to the anconeus, which runs from proximal to distal through the triceps muscle and into the anconeus compartment,7.8is preserved with the TRAP approach. A potential concern with this approach relates to the vascularity of the anconeus muscle. It is supplied proximally and distally. Cadaver injection studies have demonstrated consistent blood supply proximally into the pedicle via the middle collateral branch of the profunda brachii artery and the posterior branch of the
100
ODRISCOLL
radial collateral artery (data not shown). These are in addition to the interosseous recurrent artery that supplies the anconeus distally. In one patient operated on by this exposure, there was some suggestion of impaired vascularity of the anconeus muscle pedicle, but it was not clearly avascular. Others have all remained clearly vascular. The author prefers not to use a tourniquet in treating these fractures, but if a tourniquet is used, it should be deflated to ensure vascularity of the muscle pedicle at the completion of the procedure. Although the TRAP approach initially may appear somewhat complex based on the description, it is straightforward to understand and perform once having been demonstrated. Compared with olecranon osteotomy, it has a number of advantages and disadvantages. The advantages of the TRAP approach are that it is quicker to expose and repair, avoids hardware complicationsand nonunion, and does not potentially contribute to posttraumatic arthritis or intra-articular adhesions. The disadvantages are that it requires familiarity with the anatomy (it is not always obvious to those who have not seen the approach performed) and that the exposure of the articular surface is slightly less than that obtained with olecranon osteotomy. For the latter reason, the author still recommends olecranon osteotomy for surgeons who perform internal fixation of distal humeral fractures only occasionally. There is a subtle but important advantage to preserving the olecranon. By retaining the entire olecranon intact, one can use the olecranon, coronoid, and radial head as a three-dimensional template against which to assemble the articular fragments until adequate provisional fixation is obtained. In the author's experience, this template is extremely useful, and keeping the olecranon intact is preferable to osteotomizing and reflecting it. The author prefers to have the entire olecranon intact and slightly less view of the articular surface than to have more view but not to have the olecranon as part of the template against which to assemble and hold the fragments while they are provisionally fixed. It is not a problem after provisionally fixing the fragments, to gently retract them away from the olecranon and radial head to inspect the accuracy of articular reduction.
One final advantage of the TRAP approach is that it permits both total elbow arthroplasty and open reduction, and internal fixation, should the need arise. On occasion, these fractures in elderly patients are unfixable, and total elbow arthroplasty can be performed quite readily through this approach because it includes all of the exposure provided by the triceps-reflecting approach, the current standard for total elbow arthroplasty. ACKNOWLEDGMENTS The author is grateful to JamesD. Postier,who patiently documented the details of the approach in the photographs and illustrations,and to Drs. Michael Wiater, Tycho Kersten, and Rick Papandrea for carefully reading the manuscript and providing suggestions for the illustrations.
References 1. Alonso-Llames M: Bilaterotricipitalapproach to the elbow. Acta Orthop 43:479-490, 1972 2. Bryan RS, Morrey B F Extensive posterior exposure of
the elbow: A triceps-sparing approach. Clin Orthop 166188-192,1982 3. Campbell WC: Incision for exposure of the elbow joint. Am J Surg 15:65,1932 4. Dowdy PA, Bain GI, King GJ, et al: The midline posterior elbow incision: An anatomicalappraisal. J Bone Joint Surg Br 77696-699,1995 5. Gerber C, SchneebergerAG, Beck M, et al: Mechanical strength of repairs of the rotator cuff. J Bone Joint Surg Br 76371-380,1994 6. Jupiter JB: The surgical management of intraarticular fractures of the distal humerus. In Morrey BF (ed): Master Techniquesin Orthopedic Surgery: The Elbow. New York, Raven Press, 1994, pp 53-70 7. Kennett RP,Fawcett PR Repetitive nerve stimulation of anconeus in the assessmentof neuromusculartransmission disorders. Electroencephalogr Clin Neurophysiol89:170-176, 1993 8. Morrey B F Anatomy of the elbow joint. In Morrey BF (ed): The Elbow and Its Disorders. Philadelphia, WE3 Saunders, 1993, pp 16-52 9. Morrey B F Limited and extensile triceps reflectingexposures of the elbow. In Morrey BF (ed): Master Techniques in Orthopaedic Surgery: The Elbow. New York, Raven Press, 1994, pp 3-20 10. ODriscoll SW Elbow arthritis: Treatment options. J Am Acad Orthop Surg 1:106-116,1993 11. ODriscoll SW Elbow: Reconstruction. Frymoyer JW (ed): Orthopaedic Knowledge Update 4. Rosemont, American Academy of Orthopaedic Surgeons, 1993, pp 335-352 12. Pierce TD, Herndon JH: The triceps preserving approach to total elbow arthroplasty. Clin Orthop 14452,1998 13. van Gorder G Surgical approach in supracondylar "T'' fractures of the humerus requiring open reduction.J Bone Joint Surg Am 2278,1940 '
THE TRAP APPROACH FOR DISTAL HUMERAL FRACTURES AND NONUNIONS
14. Wadsworth T A modified posterolateral approach to the elbow and proximal radioulnar joints. Clin Orthop 151-153,1979
101
15. Wolfe SW, Ranawat CS: The osteo-anconeus flap: An approach for total elbow arthroplasty. J Bone Joint Surg Am 72:684-688,1990
Address reprint requests to Shawn W. ODriscoll, MD, PhD FRCS(C) Department of Orthopedic Surgery Mayo Clinic 200 First Street SW Rochester, MN 55905 e-mail: [email protected]
0030-5898/00 $8.00
+ .OO
THE TRICEPS-REFLECTING ANCONEUS PEDICLE (TRAP) APPROACH FOR DISTAL HUMERAL FRACTURES AND NONUNIONS Shawn W. ODriscoll, MD, PhD, FRCS(C)
Fractures of the distal humerus can be challenging to treat, to the point of being intimidating or frustrating for the operating surgeon. One recurring topic that is a constant source of question, discussion, and controversy concerns the surgical exposure. The reasons for this controversy relate not only to the need for adequate exposure but also the prevalence of complications of the surgical exposures presently used. Olecranon osteotomy is the form of surgical exposure recommended by most experts in elbow trauma for the treatment of complex intra-articular fractures of the distal humerus6 There are good reasons for this recommendation, as discussed by Ring and Jupiter in their article on distal humeral fractures elsewhere in this issue. The principal justification is for optimal exposure. Osteotomy is not without complications, however, including nonunion, intra-articular adhesions, and arthritis. Furthermore, if total elbow arthroplasty is necessary instead of open reduction and internal fixation (ORIF), the procedure is compromised by having performed an osteotomy, and nonunion of the osteotomy is much more likely.
Finally, the olecranon osteotomy as it is currently performed denervates the anconeus muscle, which receives its innervation through a terminal branch of the radial nerve passing from proximal to distal through the triceps and into the anconeus muscle. This nerve is transected as part of the soft tissue dissection for olecranon osteotomy. Although denervation of the anconeus may not seem to be of great significance, the anconeus muscle functions as the dynamic stabilizer of the elbow, and its bulk provides a vascular muscle bed for the proximal ulna and lateral side of the elbow. The ideal surgical exposure for internal fixation of distal humerus fractures permits (1) adequate exposure, (2) extensile options, (3) soft tissue dissection without osteotomy, (4) dissection in the internervous planes and not across nerves, (5) all surgical alternative procedures to be performed through the same exposure, (6) rapid rehabilitation of the involved part, and (7) subsequent reconstructive surgery incorporating the same exposure. The triceps-reflecting anconeus pedicle (TRAP)approach described in this article fulfills these prerequisites and, to the author's knowledge,
From the Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota ~
ORTHOPEDICCLINICS OF NORTH AMERICA VOLUME 31 * NUMBER 1 *JANUARY2000
91
92
ODRISCOLL
might be the only approach for the treatment of complex, comminuted articular fractures of the distal humerus that does meet all these criteria.
SURGICAL TECHNIQUE Patient Position
The patient may be placed in the lateral decubitus position with the arm hanging free over a bolster; however, the author prefers to place the patient supine, with a bolster under the ipsilateral scapula and the arm across the chest with the humerus in a vertical position. This position has the disadvantage of requiring one extra assistant but the advantage of permitting greater versatility and maneuverability, particularly while working with the elbow fully flexed (hyperflexed). Axial traction in a distal direction encourages alignment of the fracture fragments.
Superficial Exposure
In considering exposure of the distal humerus, one should be aware that “The front door to the elbow is at the Most surgical procedurw on the elbow can be done through a universal posterior skin incision just medial or just lateral to the tip of the olecran (Fig. 1).The incision starts and finishes in the midline, but the author recommends avoiding the tip of the olecranon because of the potential for skin-wound healing problems in that region. The incision is extensile, permitting increased exposure proximally, distally, or both, and may be as short as 5 to 6 cm or as long as the entire arm and forearm in extreme circumstances. For most distal humeral fractures, a skin incision about 15 cm long is appropriate. This incision has the advantage of avoiding most branches of the cutaneous n e r ~ e s . ~ The incision is carried down to the level of the deep fascia and triceps tendon, extending medially and laterally to the supracondylar ridges (Fig. 2). The ulnar nerve is identified and dissected free of its surrounding tissues, then gently retracted. An anterior subcutaneous transposition is performed routinely un-
Figure 1. “The front door to the elbow is at the back.”l0.l1 A universal skin incision for elbow operations, includinginternal fixation of distal humeral fractures, is a longitudinal posterior incision, just lateral or just medial to the tip of the olecranon. For the triceps-reflecting anconeus pedicle (TRAP) approach for internal fixation of distal humeralfractures, the incision is usually approximately 15 cm long and is placed just lateral to the tip of the olecranon,where direct pressure on the elbow can be avoided. (By permission of the Mayo Foundation.)
less medial plating of the distal humerus is not necessary. Deep Exposure
The deep exposure involves combined approaches from the lateral and medial sides of the elbow (see Fig. 2). The sequence is unimportant because one can start with the lateral or medial approach first. The author generally starts on the lateral side, then proceeds to the medial side. Part I: Lateral Side (Modified Kocher Approach)
The lateral portion of the exposure is a modified Kocher approach (Fig. 3).9 There are
THE TRAP APPROACH FOR DISTAL HUMERAL FRACTURES AND NONUNIONS
~
93
Figure 2. A and B, The TRAP approach, incorporatinga modified Kocher approach on the lateral side and a triceps-reflectingapproach on the medial side, with the two approaches converging distally at the tip of the anconeus. Medial and lateral skin flaps are raised to expose the supercondylar ridgeson either side of the distal humerus. The ulnar nerve is identified adjacent to the triceps tissue medially in preparation for subcutaneous anterior transposition. Laterally, the flaps are elevated to expose the interval between the anconeus and the extensor carpi ulnaris (ECU). This interval is defined by a septa that is barely visible and palpable beneath the deep fascia. The internal passes from the posterior aspect of the lateral epicondyle to the subcutaneous border of the ulna approximately 10 cm distal to the olecranon. FCU = flexor carpi ulnaris muscle. (By permissionof the Mayo Foundation.)
important modifications to the traditional Kocher approach. First, the lateral collateral ligament and annular ligament are preserved intact. Second, the anconeus is elevated subperiosteally off the ulna and dissected off the capsule and lateral collateral ligament complex. Third, the origins of the common extensor tendons, extensor carpi radialis longus, and brachioradialis are left undisturbed on the humerus because no exposure is required anterior to the lateral epicondyle or supracondylar ridge of the humerus. This exposure and the development of the tissue planes are accomplished most readily starting distally and progressing proximally (see Fig. 3). The interval between the anconeus and the extensor carpi ulnaris is incised starting 10 cm distal to the olecranon and extend-
ing up toward the lateral epicondyle, then the incision is carried proximally on the supracondylar ridge (see Fig. 2). The septa between the anconeus and extensor carpi ulnaris is just barely palpable and visible. The anconeus essentially forms a triangular shape bordered by a point just posterior to the lateral epicondyle, the tip of the olecranon, and the subcutaneous border of the olecranon 10 cm distally. After the incision in the deep fascia is made, the anconeus is first dissected off the septa between it and the extensor carpi ulnaris, then subperiosteally off the ulna starting distally and working proximally toward the collateral ligament. The anconeus tendon and muscle then are dissected off the annular ligament and lateral collateral ligament complex, which are preserved, and the dissection is continued be-
94
ODRISCOLL
Figure 3.A and B, The modified Kocher approach on the lateral side, commencingdistally in the interval between the extensor carpi ulnaris (ECU) and the anconeus. The anconeus muscle is dissected off the lateral side of the elbow and proximal ulna, preserving the integrity of the lateral collateral ligament complex, including the annular ligament. This outcome is accomplishedmost easily by commencingthe dissection distally and working proximally. The muscle fibers and tendon of the anconeus are dissected off the an”nular ligament, lateral collateral ligament complex, and capsule (B, top inset). The subperiosteal dissection is continued laterally beneath the anconeus muscle to the subcutaneousborder of the ulna. The posterior capsule is incised and the dissection is carried proximally between the triceps and posterior humerus (B, bottom inset). The fibers of the deep (medial) head of the triceps are dissected off the posterior humerus by sharp and blunt dissection. (By permission of the Mayo Foundation.)
neath the triceps muscle proximally along the supracondylar ridge and posterolateral distal humerus. At the level of the tip of the olecranon, an arthrotomy is made, and the dissection is continued through the capsule at that point and around posteriorly. It is essential that the collateral ligament complex not be violated. Part II: Medial Approach
The medial exposure consists of the triceps-reflecting approach to the posterior aspect of the elbow, as described by Bryan and M ~ r r e y .Starting ~,~ 10 cm distal to the olecranon (at a point corresponding to the distalmost extent of the anconeus muscle attachment), an incision is made in the periosteum on the sub-
cutaneous border of the ulna, continuing proximally along the edge of the flexor carpi ulnaris origin (see Fig. 2). The periosteum is then elevated off the subcutaneous surface of the ulna from medial to lateral, continuing beneath the anconeus, which is elevated subperiosteally off the lateral side of the ulna (Fig. 4A and €0.At the medial side of the olecranon, the incision is extended proximally along the medial border of the triceps while retracting the ulnar nerve. The triceps is reflected laterally off the distal humerus with a scalpel, carefully releasing Sharpey’s fibers from their insertion at the tip of the olecranon (see Fig. 4A and B ) . Although the triceps inserts on most of the olecranon and continues distally as a periosteal sleeve on the proximal ulna, the critical
THE TRAP APPROACH FOR DISTAL HUMERAL FRACTURES AND NONUNIONS
95
Figure 4. A and 6,The medial triceps-reflecting approach performed by reflecting the triceps laterally off the posterior distal humerus in continuity with the periosteal sleeve over the olecranon and proximal ulna. Starting at the distal tip of the anconeus (see Fig. 2), an incision is made in the periosteumalong the edge of the ulnar origin of the flexor carpi ulnaris (FCU) muscle to the medial tip of the olecranon and then is continued proximally along the medial border of the triceps. The proximal ulna is exposed subperiosteally, then the Sharpey’s fibers at the insertion of the triceps on the tip of the olecranon are released carefully by sharp dissection. This critical portion of the exposure must be performedcarefully to maintain continuity of the triceps and periosteal sleeve. After dissecting slightly more than halfway across the tip of the olecranon, a marking suture is placed in the Sharpey’s fibers precisely where this part of the tendon is to reattach to the olecranon at the completion of the procedure (6, inset). The marking suture is essentialfor anatomic reattachmentof the triceps tendon and preventionof shortening, lengthening, or medial and lateral displacement. After the completion of the procedure it is difficult to tell precisely where the Sharpey’s fibers end in the triceps sleeve. When internal fixation of distal hurneral fractures requires a medial plate, as it frequently does, the ulnar nerve is decompressedroutinelyfrom the cubital tunnel and is transposed subcutaneouslyanteriorly. Illustration continued on followingpage
portion is an area approximately 1 cm in diameter on the oIecranon. This area is located in line with the intramedullary long axis of the ulna (i.e., where K-wires are inserted for tension band fixation of an olecranon fracture). It is important to reattach the triceps precisely at that point at the completion of the procedure, so that the proper length-tension relationship is restored and the mechanical advantage of the olecranon is not lost. A marking suture is placed in the Sharpey fibers at the time of their release (see Fig. 4B, inset). At the completion of the procedure, it is difficult to tell where that
point was without a suture marking it. Proper marking permits accurate reattachment, preventing not only shortening, but also lengthening or medial or lateral displacement of the tendon. Lengthening leaves a gap between the end of the main portion of the tendon and the bone. Lateral displacement of the tendon permits detachment of the tendon because of the lateral pull of the anconeus. The dissection on the medial side now has progressed to the point at which dissection on the lateral side had stopped, such that the planes of dissection meet proximally on the
96
(YDRISCOLL
Figure 4 (Confinued).C, The dissection is continued laterally beneath the triceps and anconeus until it joins the previous plane of dissection in the modified Kocher approach from the lateral side (noted by the location of the forceps). 0,Once the modified Kocher and triceps-reflectingapproaches have been performed medially and laterally, respectively, a continuous plane of elevationexists beneath the sleeve of tr‘iceps, anconeus, and periosteum (indicated by fingers beneath the tissues). The final step is detachment of the periosteum from the subcutaneous border of the ulna at the distal end of the anconeus (0, inset) and the reflection of the triceps proximally (see Fig. 5), as one would reflect the triceps approximately following olecranon osteotomy. (By permission of the Mayo Foundation.)
humerus beneath the triceps and distally on the ulna beneath the anconeus (Fig.4C and D). The fascia1 and periosteal attachments of the distal anconeus are released, and the entire triceps and anconeus pedicle is reflected proximally (Fig. 5). Full flexion of the elbow permits the same exposure to the distal humerus as does an olecranon osteotomy except for a small portion of the articular surface of the anterior trochlea (see Fig. 5 ) .
Triceps Reattachment
The technique for triceps reattachment is particularly important, and attention to detail is mandatov. Two crisscross drill holes are
made through the ulna from proximal to distal, beginning at the normal critical attachment site of Sharpey’s fibers on the olecranon (Fig. 6A). These holes exit distally on either side of the ulna. One or more transverse holes also are drilled. A heavy nonabsorbable suture (no. 2 or no. 5 ) is placed through the triceps precisely at the location of Sharpey’s fibers (which was marked by the marking suture during the triceps reflection earlier (Fig. 6B). The suture is woven back through again in a locking stitch, similar to a modified Mason-Allen stitch as described by Gerber et al? This stitch exits the deep surface of the triceps tendon at Sharpey’s fibers and then is passed through the drill hole with a straight needle. After exiting the ulna
THE TRAP APPROACH FOR DISTAL HUMERAL FRACTURES AND NONUNIONS
97
Figure 5. A and B, The exposure of the distal humerus provided by the TRAP approach. Full flexion of the elbow is required for maximal exposure, which is almost equivalent to that provided by olecranon osteotomy, with the exception of a portion of the anterior trochlea, which can be visualized by looking in the lateral ulnohumeral articulation while retracting the ulna gently with a blunt retractor. (By permission of the Mayo Foundation.)
distally, the suture is woven over the top of the periosteum, through the anconeus muscle, then reenters the bone distally on the opposite side of the ulna (see Fig. 6 B , left inset). After being brought out of the ulna at the attachment site of Sharpey’s fibers proximally, the suture is passed through the triceps tendon
about 1 cm away from where it had entered the tendon. These two holes, where the suture passes through the tendon, should be aligned precisely with the proximal drill holes on the ulna at the attachment site of the tendon. The suture is then pulled so that all of the slack is taken up, and the tendon is pulled down to
Figure 6. A, In preparation for reattachment of the triceps, three drill holes are made in the proximal ulna, two criss-crossing at the critical attachment site of the Sharpey’s fibers on the proximal surface of the olecranon and one transversally just distal to the other two. 6,The suture technique for reattaching the triceps. The sequence of steps (leftinset)starts with a modified Mason-Allanblockingsuture, placed precisely where the marking suture had been placed on the undersurface of the triceps tendon at the termination of Sharpey’s fibers; the heavy nonabsorbablesuture is placed through the tendon and then through the drill holes in the bone, weaving back in the opposite direction and out through the tendon. After the tendon is pulled securely down against the olecranon, the suture is tied and then is woven proximately in a Bunnell fashion to imbricate the tendon and take the tension off the reattachmentsite right at the olecranon (6,top right inset). The fascia1sleeve, including the edges of the periosteumand anconeus pedicle, are closed with a running, locking suture (6, bottom right inset). Transverse stitches also are placed through the olecranon and over the periosteumon the subcutaneousborder of the ulna. (By permission of the Mayo Foundation.)
98
THE TRAP APPROACH FOR DISTAL HUMERAL FRACTURES AND NONUNIONS
the bone by the locking suture. The suture is tied tightly. Next, the free ends of the suture are woven 3 to 5 cm proximally into the triceps tendon in a Bunnell fashion, pulled, and tied so as to reef or create some slack in the distal triceps tendon (see Fig. 6B, fop right inset). The reasons for this are twofold: First, this slack permits tension in the triceps tendon to be absorbed at the proximal suture knot and less so at the reattachment to the olecranon. This protects the reattachment and lessens micromotion between the reattached tendon and bone. Second, the knotted heavy suture material at the tip of the olecranon is a significant potential source of soft tissue irritation and has even resulted in delayed wound breakdown. This additional Bunnell stitch draws the knotted suture material back down into the tendon and prevents such irritation. Furthermore, the heavy suture requires multiple knots to prevent intying, and fewer knots can be used at the olecranon because additional security for the suture is provided through the proximal knot. Another suture is placed through the transverse hole, grabbing the periosteal sleeve on either side of the ulna. Finally, a running locking suture is used to secure the free edges of the triceps, anconeus, and periosteum (see Fig. 6B, bottom righf inset). This approach, with appropriate attention to the details of tendon reattachment, permits immediate rehabilitation with full active and passive range of motion of the elbow except extension against resistance.
DISCUSSION
Since 1990, the author has used the TRAP approach, and it has become the author’s preferred approach for treating distal humeral fractures and nonunions in which intra-articular comminution is sufficient to require extensive exposure of the joint surfaces. Although the integrity of the triceps has not been specifically investigated, there have been no apparent cases of triceps detachment that the author has recognized in 20 patients treated in this manner. A number of other triceps detachment approaches have been reported, although the frequency of complications with
99
the triceps tendon has not been well documented.3,13,15 A stepwise decision-making approach should be used in exposing these fractures. The reader may recognize that the full extent of this extensile approach need not be employed in all cases. One can expose the supracondylar columns and distal humerus on either side of the triceps without detaching the triceps tendon in cases of noncomminuted or extra-articular distal humeral fractures. This situation is similar to that described by Alonso-Llames’ and Pierce and Herndon.12For minimally comminuted intra-articular fractures, the anconeus can be left attached distally and partially reflected with the triceps, which has been detached from its olecranon insertion, either medially2 or laterally.I4Leaving a sleeve of anconeus and periosteum attached to the ulna provides additional assurance of triceps integrity after repair. The advantages of this approach include not only its versatility, as part of an overall extensile approach, but also the fact that it meets the other criteria stated earlier for an ideal surgical approach. It is through soft tissues and not bone, via internervous planes, which permits all surgical options and later reconstructive procedures (such as total elbow arthroplasty) to be performed through one approach. On reexploration of patients who have had an olecranon osteotomy, the anconeus muscle has been noted to have atrophied to the point of nonexistence. The anconeus provides dynamic stability on the lateral side of the elbow, preventing varus or posterolateral rotatory instability. Although the function of this muscle has not been well understood, it would be advantageous to avoid its denervation. The anconeus also provides a vascular bed of soft tissue for protecting the lateral side of the elbow. The innervation to the anconeus, which runs from proximal to distal through the triceps muscle and into the anconeus compartment,7.8is preserved with the TRAP approach. A potential concern with this approach relates to the vascularity of the anconeus muscle. It is supplied proximally and distally. Cadaver injection studies have demonstrated consistent blood supply proximally into the pedicle via the middle collateral branch of the profunda brachii artery and the posterior branch of the
100
ODRISCOLL
radial collateral artery (data not shown). These are in addition to the interosseous recurrent artery that supplies the anconeus distally. In one patient operated on by this exposure, there was some suggestion of impaired vascularity of the anconeus muscle pedicle, but it was not clearly avascular. Others have all remained clearly vascular. The author prefers not to use a tourniquet in treating these fractures, but if a tourniquet is used, it should be deflated to ensure vascularity of the muscle pedicle at the completion of the procedure. Although the TRAP approach initially may appear somewhat complex based on the description, it is straightforward to understand and perform once having been demonstrated. Compared with olecranon osteotomy, it has a number of advantages and disadvantages. The advantages of the TRAP approach are that it is quicker to expose and repair, avoids hardware complicationsand nonunion, and does not potentially contribute to posttraumatic arthritis or intra-articular adhesions. The disadvantages are that it requires familiarity with the anatomy (it is not always obvious to those who have not seen the approach performed) and that the exposure of the articular surface is slightly less than that obtained with olecranon osteotomy. For the latter reason, the author still recommends olecranon osteotomy for surgeons who perform internal fixation of distal humeral fractures only occasionally. There is a subtle but important advantage to preserving the olecranon. By retaining the entire olecranon intact, one can use the olecranon, coronoid, and radial head as a three-dimensional template against which to assemble the articular fragments until adequate provisional fixation is obtained. In the author's experience, this template is extremely useful, and keeping the olecranon intact is preferable to osteotomizing and reflecting it. The author prefers to have the entire olecranon intact and slightly less view of the articular surface than to have more view but not to have the olecranon as part of the template against which to assemble and hold the fragments while they are provisionally fixed. It is not a problem after provisionally fixing the fragments, to gently retract them away from the olecranon and radial head to inspect the accuracy of articular reduction.
One final advantage of the TRAP approach is that it permits both total elbow arthroplasty and open reduction, and internal fixation, should the need arise. On occasion, these fractures in elderly patients are unfixable, and total elbow arthroplasty can be performed quite readily through this approach because it includes all of the exposure provided by the triceps-reflecting approach, the current standard for total elbow arthroplasty. ACKNOWLEDGMENTS The author is grateful to JamesD. Postier,who patiently documented the details of the approach in the photographs and illustrations,and to Drs. Michael Wiater, Tycho Kersten, and Rick Papandrea for carefully reading the manuscript and providing suggestions for the illustrations.
References 1. Alonso-Llames M: Bilaterotricipitalapproach to the elbow. Acta Orthop 43:479-490, 1972 2. Bryan RS, Morrey B F Extensive posterior exposure of
the elbow: A triceps-sparing approach. Clin Orthop 166188-192,1982 3. Campbell WC: Incision for exposure of the elbow joint. Am J Surg 15:65,1932 4. Dowdy PA, Bain GI, King GJ, et al: The midline posterior elbow incision: An anatomicalappraisal. J Bone Joint Surg Br 77696-699,1995 5. Gerber C, SchneebergerAG, Beck M, et al: Mechanical strength of repairs of the rotator cuff. J Bone Joint Surg Br 76371-380,1994 6. Jupiter JB: The surgical management of intraarticular fractures of the distal humerus. In Morrey BF (ed): Master Techniquesin Orthopedic Surgery: The Elbow. New York, Raven Press, 1994, pp 53-70 7. Kennett RP,Fawcett PR Repetitive nerve stimulation of anconeus in the assessmentof neuromusculartransmission disorders. Electroencephalogr Clin Neurophysiol89:170-176, 1993 8. Morrey B F Anatomy of the elbow joint. In Morrey BF (ed): The Elbow and Its Disorders. Philadelphia, WE3 Saunders, 1993, pp 16-52 9. Morrey B F Limited and extensile triceps reflectingexposures of the elbow. In Morrey BF (ed): Master Techniques in Orthopaedic Surgery: The Elbow. New York, Raven Press, 1994, pp 3-20 10. ODriscoll SW Elbow arthritis: Treatment options. J Am Acad Orthop Surg 1:106-116,1993 11. ODriscoll SW Elbow: Reconstruction. Frymoyer JW (ed): Orthopaedic Knowledge Update 4. Rosemont, American Academy of Orthopaedic Surgeons, 1993, pp 335-352 12. Pierce TD, Herndon JH: The triceps preserving approach to total elbow arthroplasty. Clin Orthop 14452,1998 13. van Gorder G Surgical approach in supracondylar "T'' fractures of the humerus requiring open reduction.J Bone Joint Surg Am 2278,1940 '
THE TRAP APPROACH FOR DISTAL HUMERAL FRACTURES AND NONUNIONS
14. Wadsworth T A modified posterolateral approach to the elbow and proximal radioulnar joints. Clin Orthop 151-153,1979
101
15. Wolfe SW, Ranawat CS: The osteo-anconeus flap: An approach for total elbow arthroplasty. J Bone Joint Surg Am 72:684-688,1990
Address reprint requests to Shawn W. ODriscoll, MD, PhD FRCS(C) Department of Orthopedic Surgery Mayo Clinic 200 First Street SW Rochester, MN 55905 e-mail: [email protected]