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Surgical Techniques

The Use of Precontoured Humeral Locking Plates in the Management of Displaced Proximal Humerus Fracture

Ricchetti, Eric T. MD; DeMola, Philip M. DO, USAF; Roman, Don BS; Abboud, Joseph A. MD

Author Information
Journal of the American Academy of Orthopaedic Surgeons: September 2009 - Volume 17 - Issue 9 - p 582-590
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Proximal humerus fracture is the second most common upper extremity fracture, following distal radius fracture. In patients aged >65 years, proximal humerus fracture is the third most common fracture, trailing only hip fracture and distal radius fracture.1–5 More than 80% of proximal humerus fractures are minimally displaced or nondisplaced and can be treated nonsurgically; however, the remaining displaced fractures typically require surgical intervention.6

Closed reduction of significantly comminuted or displaced fractures can be difficult to maintain and manage; often functional results are less than satisfactory.7–11 Although numerous surgical options have been described for managing displaced fractures, no single technique has proved to be ideal; low-quality evidence often is used to support the treatment choice.2

Recently, open reduction and internal fixation (ORIF) with locked plating has demonstrated promise in the treatment of displaced, comminuted proximal humerus fractures. This approach offers several potential advantages compared with more traditional open techniques.12–18 These benefits include improved fracture stability because of the fixed-angle construct, particularly in more comminuted fracture patterns and in osteoporotic bone; a short period of immobilization with the opportunity for earlier rehabilitation; lower risk of damage to the rotator cuff or need for implant removal; reduced hardware complications; and, in patients with more complex fractures, the potential to avoid the use of hemiarthroplasty.11,19–22 Locked plating is becoming more common; precise knowledge of and experience with the surgical technique is required to maximize clinical outcomes.

Indications and Contraindications

Indications for the use of precontoured proximal humerus locked plating in the management of displaced proximal humerus fracture include AO/ASIF type B (ie, extraarticular, bifocal) and type C (ie, intra-articular, anatomic neck) fractures, metaphyseal comminution, valgus impacted fracture, fracture with insufficient osseous contact or disrupted medial hinge, subcapital proximal humerus nonunion, proximal humerus osteotomy, and pathologic fracture.5

Relative contraindications include some fracture-dislocations, comminuted head-splitting fracture, and impression fractures involving >40% of the articular surface, in which hemiarthroplasty may be a more appropriate option; fractures in the pediatric population; severely debilitated patients or those with multiple associated comorbidities; patients with minimal ability to benefit from surgery because of neurologic impairment; and patients at high risk of local complications because of infected or deficient soft tissues.23

Surgical Technique

Preoperative Planning

A thorough preoperative evaluation should be performed, including patient history and physical examination, radiographic evaluation, and surgical planning. Key components of the history include the mechanism of injury as well as the patient's age, handedness, preinjury shoulder function, functional demands, and comorbidities. Physical examination of the shoulder should evaluate for the presence of an open or closed fracture, the location of tenderness and amount of localized swelling, the position of the humeral head on palpation (ie, located, subluxated, dislocated), active and passive shoulder range of motion (ROM), neurovascular status of the extremity, and associated cervical spine or other distracting injuries.

Standard plain radiographic views (ie, AP, axillary, scapular Y) should be obtained to determine fracture location and severity as well as humeral head position (Figure 1). Finecut coronal and sagittal CT scans of the shoulder should be obtained when intra-articular involvement is suspected, including articular comminution of the humeral head or suspected glenoid involvement, and when the fracture pattern is difficult to appreciate on plain radiographs (Figure 2). The information obtained from both plain radiographs and CT regarding the characteristics of the fracture is vital in developing a surgical plan, which includes determining intraoperative reduction maneuvers and choosing the appropriate method of internal fixation.

Figure 1
Figure 1:
AP (A) and scapular Y (B) radiographs of the shoulder demonstrating a displaced surgical neck fracture of the proximal humerus, with a minimally displaced greater tuberosity fragment.
Figure 2
Figure 2:
AP three-dimensional reconstruction of a fine-cut CT scan of the shoulder demonstrating an extra-articular, bifocal proximal humerus fracture, with fracture lines through the surgical neck and greater tuberosity.

Instrumentation

The standard precontoured proximal humerus locking plate is anatomically shaped to fit the proximal humerus. The proximal end of the plate has threaded holes to enable the creation of a locked construct in the humeral head, and the distal, or shaft, end of the plate has multiple holes that can be used in a locking or nonlocking (ie, compression) manner (Figure 3). Depending on which locking holes are used in the proximal end of the plate, different constructs with diverging screw patterns can be created in the humeral head. Kirschner wires (K-wires) can be placed through the small holes in the proximal end of the plate to achieve temporary intraoperative fixation or to place permanent sutures for additional fracture stability. Longer plates are available, with up to 12 holes in the shaft end. The associated set for the plate should contain all of the necessary equipment for the procedure, including the appropriately sized screws (locking, cortical, and cancellous), K-wires, drill bits, drill guides, screwdrivers for locking and nonlocking screws, depth gauge, measuring device, insertion guide, and sleeves for the drill bits or locking screws. Additional items used in the procedure include reduction clamps and retractors, 1-mm Cottony II Dacron (Deknatel, Mansfield, MA) sutures with needles for tagging the rotator cuff, bone graft or bone graft substitutes, a mechanical arm-holding device for optimal positioning of the extremity, and fluoroscopic imaging equipment.

Figure 3
Figure 3:
Precontoured proximal humerus locking plates. The proximal end of each plate has locking holes that enable the creation of a locked construct in the humeral head. The multiple holes in the distal (ie, shaft) end of the plate may be used for locking or compression screws.

Anesthesia and Patient Positioning

General anesthesia is typically administered. This is often coupled with regional anesthesia in the form of an interscalene nerve block on the affected side. However, some surgeons, including the senior author (J.A.A.), avoid the use of regional anesthesia because it may make it difficult to assess the neurologic status of the extremity postoperatively.

The patient is placed in the beachchair position, with the torso at approximately 45° to 60° relative to the horizontal plane. The arm and shoulder are positioned off the edge of the table to allow full shoulder ROM (video, Surgical Procedure). The head, neck, and body should be appropriately stabilized.

Once the patient has been positioned, fluoroscopic imaging equipment is brought in to confirm free access of the machine during the procedure (Figure 4). The unit should be positioned at the head of the bed and rotated over the shoulder to allow for optimal fluoroscopic imaging intraoperatively. Care should be taken to ensure that views will not be blocked by the bed or the patient's body. The equipment must be sterilely draped to avoid contamination.

Figure 4
Figure 4:
A, For surgery to repair displaced proximal humerus fracture, the fluoroscopy unit is placed at the head of the bed and rotated over the shoulder to allow for optimal imaging intraoperatively. B, The unit must be sterilely draped to eliminate the risk of contamination.

Surgical Approach and Exposure

The deltopectoral approach is preferred for ORIF with precontoured locked plating. The skin incision is begun at the tip of the coracoid process proximally and is extended 10 to 15 cm distally to the deltoid tuberosity. Following exposure of the skin and the subcutaneous tissues, the cephalic vein, deltoid muscle, and pectoralis major muscle are identified. The cephalic vein marks the interval between the deltoid muscle laterally and the pectoralis major muscle medially. The cephalic vein is a major draining vein of the arm and should be preserved. It is retracted laterally to protect the many deltoid branches that enter on this side.

Next, the internervous plane between the deltoid (ie, axillary nerve) and the pectoralis major (ie, medial and lateral pectoral nerves) is developed (Figure 5, A). Typically, deltoid detachment is not needed. Once through the interval, an extensive hematoma is usually encountered. This blood is evacuated by aspiration or digitally to expose the fracture, after which the neurovascular structures (ie, axillary and musculocutaneous nerves) are identified.

Figure 5
Figure 5:
A, Exposure of the deltopectoral interval in a patient with proximal humerus fracture. The deltoid muscle appears lateral (arrowhead), and the pectoralis major muscle appears medial (arrow). The cephalic vein (asterisk) is shown overlying the deltoid, lateral to the interval. B, The long head of the biceps tendon (asterisk) is identified and tagged with nonabsorbable suture. This tendon is important in orienting the anatomy of the proximal humerus following fracture, particularly the location of the greater and lesser tuberosities. The biceps tendon may be divided intra-articularly at its origin and tenodesed at the rotator interval following locked plating.

Adequate muscle paralysis with anesthesia is essential to ensure sufficient exposure of the fracture site and to allow for ease of reduction. A muscle retractor, preferably a deltoid retractor, is placed for soft-tissue retraction. Slight abduction of the arm relaxes the deltoid muscle and enables better access to the humeral head.

The long head of the biceps tendon is identified at the upper border of the pectoralis major muscle, and its course is followed proximally (Figure 5, B). This tendon is important in orienting the anatomy of the proximal humerus because it runs in the intertubercular groove between the greater and lesser tuberosities. The biceps tendon is particularly useful for orientation in the presence of four-part fractures, when anatomy can be significantly distorted.

One fracture line usually runs close to the intertubercular groove and separates the greater tuberosity and lesser tuberosity fragments. When the intertubercular groove cannot be reconstructed during fracture reduction and fixation, or when the long head of the biceps tendon is damaged, the tendon is divided intraarticularly at its origin and tenodesed at the rotator interval following locked plating.

Fracture Reduction and Fixation

Prior to attempted fracture reduction, the rotator cuff is generously tagged with nonabsorbable sutures anteriorly, posteriorly, and superiorly to assist with reduction of the fracture fragments and, ultimately, to reinforce fixation of the fracture to the plate (Figure 6). Following suture of the rotator cuff and in the presence of a fracture with multiple fragments, the head fragment can be gently manipulated under direct visualization with a periosteal elevator introduced into the fracture gaps. The elevator is helpful in disimpacting the head from the humeral shaft. Vascular supply to the fracture fragments should be assessed; bleeding cancellous fracture surfaces are desirable. Excessive exposure of the fracture fragments should be avoided to prevent disruption of the blood supply.

Figure 6
Figure 6:
A and B, Intraoperative photographs illustrating tagging of the rotator cuff with nonabsorbable sutures before attempted reduction of a proximal humerus fracture. The rotator cuff should be generously tagged anteriorly, posteriorly, and superiorly not only to assist with reduction of fracture fragments but also to reinforce fixation of the fracture to the locked plate.

Indirect reduction maneuvers can be achieved without force by means of longitudinal traction on the arm, abduction or adduction, rotation, and lateralization of the humeral shaft while pulling on the rotator cuff sutures. Pull of the pectoralis major muscle often causes medial displacement of the humeral shaft in the patient with subcapital fracture. In the presence of varus tilt of the head fragment, the position can be corrected by pulling on the superior suture loop through the supraspinatus tendon while maintaining longitudinal traction on the arm. Tagged tuberosity fragments can be reduced to the humeral shaft and may also indirectly reduce a head fragment.23

Once the head fragment has been reduced, the tuberosities are pulled together with the sutures and fitted via digital manipulation. Nondisplaced tuberosities are essential in achieving good functional outcomes. Poor results have been shown with improper reduction of the tuberosities.24,25 In comminuted fractures, temporary fixation with K-wires is recommended to hold the fracture reduction. Care must be taken so that the wires do not interfere with subsequent plate positioning. In the patient with significant comminution and bone loss of the humeral head or with an osteoporotic head, consideration should be given to repairing the defects with autograft or allograft bone, demineralized bone matrix, or Norian SRS (Synthes, West Chester, PA) through a cortical window.

After temporary fracture reduction is achieved, the precontoured locking plate is positioned 5 to 10 mm lateral to the intertubercular sulcus and 15 to 25 mm caudad to the tip of the greater tuberosity. When necessary, the plate contour can be fine-tuned to anatomically match the neck-shaft angle, for which we recommend using a large plate bender (Figure 7, A). The deltoid muscle insertion should not be detached during plate placement. Proper placement of the plate is important. Placing the plate too high increases the risk of subacromial impingement or violation of the rotator cuff; placing it too low can lead to suboptimal screw placement in the humeral head.

Figure 7
Figure 7:
A, Photograph of a large plate bender, which may be used for additional contouring of a locking plate to anatomically match it to the proximal humerus neck-shaft angle. B, An insertion guide (left) can be locked to the proximal end of the plate (right) to facilitate placement of the proximal locking screws.

Before placement of locking screws, a shaft that is lying medial can be brought lateral into a reduced position against the plate with a 3.5-mm cortical screw introduced into the first hole distal to the fracture site. We recommend that this screw hole be filled first. Tightening of the 3.5-mm cortical screw in this hole for reduction, however, may lead to slight upward migration of the plate on the greater tuberosity. Correct plate position should be checked and the adequacy of fracture reduction confirmed on fluoroscopic imaging (Figure 8). K-wires can be temporarily inserted into the screw holes to hold the plate in place during imaging. Evidence suggests that shortening of the humerus by impaction of a comminuted surgical neck fracture may be acceptable because the resultant increase in area of bony contact and medial buttressing improves the stability of the construct.26

Figure 8
Figure 8:
Following reduction of a proximal humerus fracture and provisional placement of the locked plate, correct plate position and the adequacy of fracture reduction should be confirmed on fluoroscopy.

With the plate appropriately positioned and the fracture reduced, proximal and distal screws are prepared and placed in the plate (Figure 9). All fracture fragments must be reduced and the plate correctly aligned before the locking screws are placed because these screws will prevent further compression or reduction of the fracture, or reduction of the plate to bone. The proximal end of the plate is designed with locking holes to create a locked construct in the humeral head. An insertion guide can be used to facilitate placement of the proximal locking screws (Figure 7, B). When drilling the proximal screw holes into the humeral head, we favor a stepwise advancement of the drill bit until it encounters resistance from subchondral bone.

Figure 9
Figure 9:
A, Photograph demonstrating placement of locking screws in the proximal end of the plate during surgery to repair proximal humerus fracture. B, A guide sleeve can be inserted into the locking screw holes to ensure proper placement and engagement of the locking screws in the screw holes.

Screw length is determined with a depth gauge and confirmed with fluoroscopy. The use of imaging in determining screw length is particularly important in thin osteoporotic bone, in which drill depth cannot always be accurately detected by depth gauge alone. This confirmatory step decreases the risk of placing locking screws that protrude through the articular cartilage of the humeral head.

Proximal locking screws are inserted with a torque-limiting attachment mounted on the drill. The last turns should be done by hand to protect the delicate locking threads on the screw hole and screw head. To maximize construct stability, we recommend placing as many divergent locking screws in the humeral head as the plate will allow. We prefer to insert the tip of each locking screw to a distance at least 5 to 10 mm short of the opposite subchondral bone. This depth, in conjunction with the use of self-tapping locking screws, reduces the risk of screw penetration into the glenohumeral joint should impaction or collapse of the fracture occur.

The distal, or shaft, end of the plate has holes that may be filled with locking or nonlocking (ie, compression) screws. In the humeral shaft, a minimum of two bicortical screws should be used to prevent hardware failure. Three bicortical screws should be used in osteoporotic bone. Insertion of further locking screws into the shaft creates a fixed-angle construct for bridging of metaphyseal fracture. To allow the plate to function as a bridging device, holes at the metaphyseal level should not be filled in the presence of metaphyseal comminution. The segment of plate that is not filled with screws allows absorption of bending moments, thus preventing implant breakage resulting from excess stress concentration at the boneimplant interface.27 A longer plate may be necessary to manage fracture with a significant zone of metaphyseal comminution.

When all screws have been placed, the rotator cuff sutures are threaded through the small holes in the proximal end of the plate and tied down for additional fixation. Once tied to the plate, the sutures function to neutralize the tensional forces of the rotator cuff, thereby further increasing the stability of the fracture. The indication for suture use should be generous because the added stability allows for early postoperative exercises and reduces the risk of loss of reduction and malunion.11,14

With fixation complete, passive motion of the shoulder with direct fracture visualization, followed by fluoroscopic imaging, should be performed to check construct stability. Particular attention should be paid to the quality of the reduction, plate position, stability, and avoidance of penetration of the locking screws into the glenohumeral joint. Once adequate fixation is confirmed, the wound is irrigated and closed in layers. During wound closure, we place a drain deep to the deltopectoral interval to close down any dead space. A biceps tenodesis is performed when indicated. Exercises should be permissible early in the postoperative period in the patient with a stable, adequate reduction.

Postoperative Care and Considerations

Postoperatively, the arm is immobilized in a sling. The drain is removed 2 days after surgery. The timing of shoulder rehabilitation is determined by fracture stability, bone quality, and patient compliance.28 Passive ROM exercises (ie, pendulums, passive forward elevation, external rotation) generally are begun on the first postoperative day provided that a stable reduction is achieved. Active ROM of the elbow, wrist, and hand is also begun immediately after surgery. The patient then progresses through a three-phase rehabilitation program,29,30 consisting of passive assisted exercises early, active exercises starting at approximately 6 weeks postoperatively, and strengthening or resisted exercises beginning 10 to 12 weeks after surgery. Early passive assisted exercises help to avoid adhesion formation. No limitation of exercises within the pain-free ROM is necessary during this time provided that bone stock is good and medial buttressing adequate. Shoulder strengthening and resistance exercises are initiated only after bony consolidation is confirmed on plain radiographs and adequate coordination of the extremity has been achieved (video, 6-Month Postop ROM).

Standard AP, axillary, and scapular Y radiographic views are taken immediately after surgery. Routine follow-up radiographs are taken 3, 6, and 12 weeks postoperatively, then again at 6 and 12 months following surgery (Figure 10). Plate removal is generally not necessary.

Figure 10
Figure 10:
AP (A) and axillary (B) radiographic views of the shoulder demonstrating a healed proximal humerus fracture following fixation with a precontoured proximal humerus locking plate. The fracture and plate show good alignment, with no evidence of screw penetration into the glenohumeral joint.

Summary

ORIF with locked plating has several potential advantages compared with other surgical techniques in the treatment of displaced, comminuted proximal humerus fractures.12–18 Complications, although infrequent, include osteonecrosis of the humeral head, nonunion, malunion, screw penetration into the glenohumeral joint, secondary displacement of the plate from the proximal humerus, subacromial impingement, and infection.5,11,27 Studies are needed to directly compare the outcomes of locked plating with those of other common surgical techniques, including hemiarthroplasty, to determine the optimal indications and limitations of each method.

The primary goal of surgery should be to create a construct that is sufficiently stable to allow early ROM of the shoulder. Important factors to consider in selecting the optimal surgical technique and implant to achieve this goal include patient age, fracture pattern and displacement, bone quality, humeral head vascular status, preexisting rotator cuff disease or degenerative changes, associated injuries, and patient function.5,11 Locked plating may be the ideal treatment choice when adequate fixation to allow early rehabilitation is not possible with other nonsurgical or surgical measures.

Pearls

  • Knowledge of the precise location of the musculocutaneous nerve, anterior and posterior humeral circumflex arteries, and axillary nerve is critical. Failure to locate these structures or straying too far medial with the dissection can be dangerous.
  • A mechanical arm-holding device facilitates surgery by providing good support of the arm and shoulder girdle throughout the procedure.
  • Adequate muscle paralysis throughout surgery is helpful in fracture exposure, reduction, and fixation.
  • Inadequate reduction and stabilization of the fracture must be avoided. The fracture should not be plated prior to attaining an adequate reduction. The plate must be long enough for the fracture pattern. A generous number of screws should be used within the humeral head. Bone graft or bone graft substitute should be used when needed. Rotator cuff sutures should be used for added stability. Fluoroscopic imaging should be used throughout the procedure.
  • Subacromial impingement during abduction can be prevented by placing the plate appropriately caudad to the greater tuberosity. The surgeon should take care when attempting to reduce a markedly medially displaced shaft fragment to the plate because tightening of the first screw can cause cranial displacement of the plate.
  • The risks and benefits to the patient must be considered when revision of fracture reduction and improved positioning of the implant are contemplated.
  • Humeral head screw length should be confirmed fluoroscopically to avoid the possibility of perforating the glenohumeral joint and causing iatrogenic articular cartilage damage.

Pitfalls

  • Overly extensive exposure of the fracture fragments may result in interruption of the blood supply to the articular fragments.
  • Inadequate reduction of displaced head fragments, particularly in the presence of a varus malreduction, can lead to poor functional results.
  • Displaced tuberosities that have been insufficiently reduced or inadequately fixed to the plate either with screws or strong rotator cuff sutures may cause secondary displacement or subacromial impingement.
  • Incorrect placement of the locking screws in the plate can result in poor locking of the screw head in the plate screw hole, cold welding, or screw loosening.
  • Too few bicortical screws in the humeral shaft can lead to hardware failure and displacement of the plate from the shaft.

References

Evidence-based Medicine: Levels of evidence are described in the table of contents. In this article, no level I studies are cited. Level II studies include references 3, 4, and 7. References 2, 10, and 24 are level III studies. Level IV studies include references 8, 9, 12–18, and 25–27. Level V studies include references 1, 5, 6, 11, 21, 23, and 28–30. References 19, 20, and 22 are biomechanical studies.

Citation numbers printed in bold type indicate references published within the past 5 years.

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