Radiologic Assessment - Solutions for Complex Upper Extremity Trauma

Appropriate imaging assessment of patients with malunions begins with a plain radiograph trauma series of the shoulder. This includes an anteroposterior and lateral view in the plane of the scapula and an axillary view. These views usually provide sufficient information regarding the position of the fragments as well as the bone quality; however, supplemental internal and external rotation views can provide more information if necessary. In patients previously treated with internal fixation, radiographic evidence of loosening may be an indication of infection. In these cases, one should consider aspiration and culture of the joint.

Computed tomography (CT) is often essential to evalu- ate the full extent of injury. The degree of tuberosity displacement and certain fracture patterns, such as head splitting fractures, articular impression fractures, and chronic fracture-dislocations are best visualized with CT scans that allow three-dimensional evaluation of the fragments.^10,11Morris et al reported that CT identified axial malposition of the greater tuberosity that was not appre- ciated on plain x-ray in 10 of 18 patients. Furthermore, plain films were inadequate in assessing displacement of the lesser tuberosity in all 18 patients.¹¹ Three-dimensional CT reconstructions also aid in the understanding of the position of malunited fragments.¹²

Other imaging modalities that can be useful to the surgeon include magnetic resonance imaging (MRI) and scanograms. MRI helps delineate soft tissue pathology, especially with regard to the rotator cuff and labrum.

MRI also allows earlier identification of avascular necrosis than is provided by plain films. In patients with hard- ware from previous surgery, artifact can diminish the information available from MRI. Scanograms aid in determining the proper length of the humerus and are especially useful in proximal humerus reconstruction with

hemiarthroplasty. The scanogram can establish the proper height for the prosthesis; thereby allowing the surgeon to reestablish the appropriate tension of the soft tissues.

Classification

To date, no universally accepted classification system for proximal humerus malunions exists. Many authors have simply modified the commonly used classification of acute proximal humerus fractures developed by Neer and applied it to their series of malunions.^1,9,12Other authors have attempted to develop original classification systems useful in determining the treatment approach to the malunion.

Beredjiklian et al¹³proposed a system of categorizing osseous and soft tissue defects. Osseous abnormalities were categorized as malposition of the greater or lesser tuberosities by more than 1 cm (type I malunion); intraarticular incongruity or a step-off of the articular surface of 5 mm (type II malunion); and malalignment of the articular segment by more than 45 degrees in any of the three planes (type III malunion). They categorized soft tissue abnormalities more broadly: soft tissue contracture, rotator cuff tear, and subacromial impingement. Although not all- inclusive, this classification system is useful in providing an overview of the involved pathology with the goal of treating each component.

Boileau et al¹²developed a general classification system relating to sequelae of proximal humerus fractures that included proximal humerus malunions. Category 1 included intracapsular/impacted fracture sequelae: type I – cephalic collapse and necrosis; type II – chronic dislocation or fracture-dislocation. Category 2 dealt with extracapsular/

disimpacted fracture sequelae: type 3 – surgical neck nonunions; type 4 – severe tuberosity malunions (Fig. 7–1).

Category 1 fractures can be reconstructed with a proximal humerus arthroplasty without a greater tuberosity osteotomy with predictably good results. Category 2 fractures require a greater tuberosity osteotomy and yield less predictable, usually poorer results. Boileau’s system does not account for malunions treated with osteotomy and internal fixation without the use of proximal humerus arthroplasty.

Treatment

The appropriate treatment of proximal humerus malunions depends on myriad factors. The patient’s overall state of health, physiologic age, degree of pain, and loss of function relative to his or her needs all warrant consider- ation prior to embarking on a treatment course. Patients Ch07_p60-69.qxd 1/11/08 10:04 PM Page 62

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with a low activity level, whose pain is tolerable, and who are able to remain independent despite the injured shoulder can reasonably be treated conservatively. Others for whom conservative treatment would be reasonable include those with medical conditions that put them at severe risk for surgery and patients who are not able to participate in postoperative rehabilitation.

Nonsurgical Treatment

Physical therapy and pain control are the cornerstones of conservative treatment. The goal of therapy is to maxi- mize and maintain the shoulder’s ROM and to strengthen the shoulder musculature. Scapular strengthening can help regain functional strength and some ROM. It is important to remember that in some patients, glenohumeral motion may be limited by bony impingement.

The use of nonsteroidal antiinflammatory medications and intraarticular steroid injections can decrease the secondary inflammatory changes that cause pain. Modalities, including heat or cold compresses, electrical stimulation, ultrasound, and phonophoresis, may decrease some of the pain in these patients. At times, patients who are not surgical candidates benefit from consultation with a chronic pain doctor. These specialists often use antidepressants,

biofeedback, and/or nerve root injections to help with difficult pain management problems.

Surgical Treatment

There are two categories of surgical treatments for proximal humerus malunions: humeral head preserving and humeral head sacrificing. When the blood supply to the humeral head is viable, the articular surface is preserved, and if the patient has good bone quality, humeral head preserving procedures are indicated. These are usually cases of two-part and some three-part malunions. Recon- struction in these cases primarily involves osteotomies and fixation of the tuberosities or the surgical neck along with soft tissue reconstruction. In the cases of surgical neck malunion or tuberosity fractures, removal of bone protuberances and soft tissue releases can significantly improve outcome, especially in the presence of a supple glenohumeral joint. Arthroscopic releases have been considered in these difficult cases, especially when associated with posttraumatic arthritis; however, Holloway and Iannotti¹⁴ reported that the only successful results were in primary cases of posttraumatic arthritis without an element of significant malunion. Arthroscopy can be considered in cases where posttraumatic bursitis and Figure 7–1 Surgical classification of sequelae of proximal humerus fractures as defined by Boileau et al.¹²

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secondary outlet impingement are significant causes of pain and disability. Tuberosity spur removal and capsular releases do not correct the underlying problem.

Humeral head sacrificing procedures are indicated when the head has developed or is likely to develop avascular necrosis. They are also indicated when extensive damage to the articular surface is present. These procedures, which include hemiarthroplasty or total shoulder replacement (TSR), are usually reserved for some three- part malunions, most four-part fractures, head splitting injuries, and humeral head impression defects involving more than 40% of the articular surface.¹⁵The indications for hemiarthroplasty versus TSR depend on the condition of the articular surface of the glenoid and the integrity of the rotator cuff.

Techniques

Humeral Head Sparing Techniques

Two-part surgical neck malunions, with resultant varus deformity and loss of forward elevation and internal and external rotation, are rare. As mentioned above, increased anterior angulation 45 to 55 degrees causes decreased forward elevation, which correlates with Beredjiklian’s classification system in which 45 degrees of angulation in any plane warrants surgical reconstruction. Because the incidence of these malunions is low, there is not much in the literature discussing the methods and results of treatment. Solonen and Vastamaki¹⁶preformed a valgus wedge derotational osteotomy through as standard deltopectoral incision. The osteotomy was secured with a T-shaped AO plate. During this approach, the axillary nerve must be dissected free and protected. Soft tissue adhesions and contractures need to be addressed, and humeral height needs to be reestablished. With the advent of locked

plating, rigid fixation can be achieved, allowing for early ROM (Fig. 7–2). In certain cases in which the joint remains supple despite severe deformity on x-ray, soft tissue contracture releases and removal of prominent bone provide good results.

The procedure for treatment of two-part greater tuberosity malunions is similar to that used for acute tuberosity fractures. Often these malunions are addressed through an anterosuperior approach, with the arm draped free and the patient in a modified beach-chair position.⁶The authors rec- ommend releasing a portion of the anterior deltoid in addition to the usual deltoid split, which helps mobilize the soft tissues. Because of the extensive disease in the subacromial space, an acromioplasty and release of the coracoacromial ligament are often performed. The greater tuberosity is then osteotomized (Fig. 7–3A). As opposed to lesser tuberosity, osteotomies that are usually uniplanar, greater tuberosity osteotomies are often biplanar. Distinguishing fracture callus from the tuberosity fragment is often difficult; thus, it is safer to err on osteotomizing too large a piece of bone. Most of these fractures originate at the bicipital groove, so the biceps tendon is a useful landmark for osteotomy orienta- tion. It is very important to protect the axillary nerve, especially as it courses through the quadrilateral space, during the osteotomy. To help control the free fragment, heavy nonabsorbable sutures are placed at the insertion of the rotator cuff into the greater tuberosity. A crucial part of the procedure involves lysis of contractures and mobilization of the soft tissues. A superior and posterior capsulotomy may help, as will lysis of extra- and intraarticular adhesions. The rotator cuff should be mobilized as well. We have found that, in these patients, subacromial decompression alone rarely works. One may consider arthroscopic subacromial decompression, tuberoplasties, and capsular release, as these can provide a successful outcome. Again, with significant displacement of the tuberosity, osteotomy is necessary.

Figure 7–2 Varus surgical neck malunion treated with valgus derotational osteotomy and secured with proximal humerus locking plate.

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At this point, the greater tuberosity should be able to be mobilized to the donor site (external rotation of the humerus may be necessary). In some lesser tuberosity malunions, the piece is very small and may benefit from excision followed by repair of the subscapularis tendon.

Prior to reapproximating the tuberosity fragment to the donor site, the site needs to be decorticated to a bed of bleeding cancellous bone. In addition, the anterior glenoid rim should be examined through the invariable rent in the rotator interval between the supraspinatus and subscapularis. There might be an associated Bankart lesion, especially if the initial injury was a fracture-dislocation.

These lesions, if present, can be repaired through the tear in the rotator interval or arthroscopically prior to tuberosity fragment fixation. The tuberosity segment can then be shaped to match the donor site. Rigid fixation of the fragment to the shaft is the goal and can usually be achieved with one or two AO screws with washers. The screws should be angled inferomedially so that they engage the medial cortex of the humeral shaft, while remaining inferior to the articular surface of the humeral head (Fig. 7–3B). Once fixation and ROM are assessed and found to be satisfactory, the rotator interval and deltoid are repaired.⁶Other treatment options include figure-eight tension-band constructs with nonabsorbable suture or wire. If the fragment is small, the rotator cuff may be detached and repaired primarily back to the bed with suture anchors following excision of the fragment.

Malunions resulting from three-part fractures, four- part fractures, and fracture-dislocations are extremely challenging reconstructions. If avascular necrosis is absent and the articular surface of the humeral head is preserved,

osteotomies and internal fixation of the malunited seg- ments, as described above, are indicated. In some cases, anatomic reconstruction may not be possible; however, satisfactory results are still obtained if the tuberosities are fixed about the head and shaft in such a way that motion is preserved without impingement.

In certain cases, the humeral head may have articular surface damage that involves 40% of the surface. In these cases, the head may be salvageable. The McLaughlin procedure, which involves transferring the subscapularis insertion, with or without the lesser tuberosity, into the defect may be indicated in situations such as these.

Humeral Head Sacrificing Techniques

Often the sequelae of three- and four-part fractures require prosthetic replacement. Appropriate soft tissue balancing is key to achieving a stable, well-functioning shoulder. Careful attention should be paid toward recreating humeral height, tuberosity alignment and fixation, and humeral head version. This is often best accomplished by osteotomizing the tuberosities to, in essence, createa four-part fracture, which is then reconstructed around the implant. A modular shoulder system, with different component sizes and eccentric humeral heads, allows for better soft tissue tensioning. It also allows intraoperative prosthetic trialing to improve stability and tuberosity position.¹⁷The decision to use a cemented versus noncemented humeral prosthesis should be made at the time of surgery and based on bone quality and component stability.

Humeral head prosthetic replacement is usually performed through an extended deltopectoral approach. Prior Figure 7–3 (A) Greater tuberosity malunion osteotomized with circumferential release of adhesions around the tuberosity-tendon unit.

The fragment is then shifted anteroinferiorly into an area that has been decorticated. (B)Fix- ation of the tuberosity with two cancellous screws and a figure-eight tension band.

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to addressing the bony pathology, the surgeon should deal with the associated soft tissue pathology. If external rotation contractures are present, a lesser tuberosity osteotomy or subscapularis lengthening should be performed. If the shoulder capsule is contracted, it should be released cir- cumferentially at the glenoid edge. Subscapularis tendon adhesions require lysis, and the rotator cuff needs to be mobilized. At this point, the integrity of the cuff should be evaluated, as an irreparable tear is a relative contraindica- tion to TSR.

Tuberosity position should be assessed to determine whether or not an osteotomy is necessary. If there is a block to external rotation at 20 degrees or less or elevation is 90 degrees, greater tuberosity osteotomy is indicated.

If the tuberosity is malpositioned, but would lie below the level of the articular surface of the prosthesis, an osteotomy may not be necessary. However, in these cases, make sure that the position of the tuberosity does not block the appropriate insertion point for the stem.¹⁸If the lesser tuberosity is not replaced appropriately, the humeral head may subluxate posteriorly or coracoid impingement may occur with internal rotation. Although the osteotomy may sacrifice some bone, enough bone should remain at- tached to the rotator cuff to facilitate repair. There should also be a significant surface area of bony contact between the fragment and the humeral shaft.

The level of the humeral head osteotomy must account for any surgical neck malalignment and loss of height. As mentioned above, in severe cases, a scanogram can be help- ful to elucidate the appropriate height. Once the humeral

head osteotomy is completed, the head should be sized and the glenoid inspected. Glenoid erosion in the setting of an intact or repairable rotator cuff is an indication for TSR.

Shoulder stability, in large part, depends on proper height and version of the humeral component. The height must allow for repositioning of the tuberosities below the articular surface of the prosthesis and for appropriate soft tissue tensioning. Usually the prosthesis is retroverted 20 to 35 degrees; however, in the event of a chronic posterior dislocation, a posterior impression fracture, or recurrent instability, decreasing the amount of retroversion can improve stability.

Securing the tuberosities to the implant and humeral shaft can be done in a variety of ways. The senior author (DMD) uses five heavy, nonabsorbable sutures. Two of the sutures are placed through the tuberosity followed by insertion through the medial flange of the prosthesis. Two additional sutures are placed through each tuberosity and brought back to themselves. The fifth suture is placed through the shaft then brought up in a figure-eight fash- ion through the tuberosities. Appropriate drill holes are made in the humeral shaft, and the sutures are passed prior to implantation of the prosthesis. Shingling and bone grafting of the tuberosity are essential to ensure healing of the tuberosity back to the humeral shaft (see Chapter 6 for a more thorough description of the tech- nique). An important point to be made is that in cases of type I and II malunions (as defined by Boileau et al), one can accept the stem being in varus and possibly perform a tuberosity osteotomy (Fig. 7–4).

Figure 7–4 Preoperative radiograph (A)of a four-part malunion, and (B)postoperative radiograph of fracture treated with hemiarthroplasty, in which good results were achieved by placing stem in slight varus.

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Prior to closure of the shoulder, stability should be assessed and the limits of passive ROM determined. It is important to document the intraoperative passive ROM that does not stress the repair of the tuberosities, as this will define the limits of ROM during the initial physical therapy phase. The rotator cuff and deltoid are repaired, and the wound is closed over a drain in layers.

Recently, in cases of severe tuberosity malunion (Boileau et al type III or IV), some surgeons have used the reverse-type shoulder prostheses because reported results for these patients are universally poor.

Postoperative Rehabilitation

If rigid internal fixation is achieved or if a prosthesis is used, passive ROM exercises are started on postoperative day 1. The limits of this motion are based on intraoperative stability. Gradually, assisted ROM exercises are insti- tuted. Isometric exercises of the deltoid and rotator cuff are initiated once radiographic evidence of fragment union is visualized (usually about 6 weeks postoperatively). At 10 weeks, resistance exercises to strengthen the rotator cuff and deltoid can be started.

Results

There is a relative dearth of literature on results of operative treatment of proximal humerus malunions. Further- more, the bulk of the literature that does exist addresses the entire spectrum of posttraumatic sequelae of proximal humerus fractures, not just malunions. This makes com- parisons between different series complicated. Regarding two-part malunions of the surgical neck, one study exists.¹⁶Solonen and Vastamaki described the use of a valgus wedge derotational osteotomy secured with an AO T-plate in 7 patients. Preoperative varus angulation ranged from 40 to 60 degrees. Five of 7 achieved near-normal to normal results with much improved ROM. Two of the 7 had poor results, which the authors attributed to preoperative factors, such as associated soft tissue pathology and poor motivation for rehabilitation.

Few studies look solely at the results of reconstructive procedures for isolated tuberosity malunions. Morris et al reported on 3 of 6 patients with isolated greater tuberosity malunions treated by osteotomy and repositioning of the fragment. They concluded that such a procedure leads to a substantial increase in shoulder function.¹¹

In Beredjiklian’s study, 11 of the 39 reported cases involved isolated tuberosity malunion (type I malunion).¹³ Eight of the 11 were treated with an osteotomy of the tuberosity and soft tissue reconstruction. Overall, 6 of 8 (75%) patients had a satisfactory result. Seven of the 8 had correction of the deformity to within 5 mm of the anatomic position. All patients reported lessening of their pain, and

7 of the 8 reported minimal to no pain. Functional capacity improved in 75% of the patients as well.

Results on prosthetic replacement for proximal humerus malunion are more prevalent. Tanner and Cofield¹⁹reported on 49 shoulders treated with arthroplasty for acute or chronic proximal humerus fractures. Sixteen of the 27 shoulders in the chronic fracture group were documented malunions with articular surface incongruities. Because this study was primarily a comparison of acute and chronic fracture treatments, the results as they pertain to malunions is limited. That being said, a few generalizations can be made.

Mean age was 11 years younger in the chronic fracture group, and more careful attention was paid to postoperative immobilization and rehabilitation. To that end, ROM was better in the chronic group. Complications were more frequent in the chronic group and were attributed to the difficulty of the surgery, extensive scarring, and distorted anatomy.

Dines et al¹⁷reported on a series of 20 arthroplasties performed for chronic posttraumatic changes of the proximal humerus. This series included malunions, nonunions, avascular necrosis, and impression fractures. Preoperative malunion of the tuberosities or humeral head was present in 8 of 20 patients. Twelve of the 20 required an osteotomy based on external rotation 20 degrees and abduction 90 degrees. Overall, 90% of the patients had fair, good, or excellent results. When looking at the malunion group in isolation, The Hospital for Special Surgery Shoulder score improved from 27.4 preoperatively to 69.8 postoperatively.

It was noted that patients younger than 70 and those that did not require a tuberosity osteotomy had better results.

Furthermore, the authors found that using a modular- designed prosthesis facilitated soft tissue tensioning and tuberosity repair.

Norris et al¹reviewed the results of 23 patients who failed the initial treatment for three- or four-part fractures and were subsequently revised to prosthetic arthroplasty.

Initial treatment was operative for 13 of 23 and nonopera- tive for 10. Seventeen patients were classified as having malunions. Of note, all 10 three- or four-part fractures ini- tially treated closed went on to develop malunions, and 7 of 13 (54%) treated operatively developed malunions.

Norris’ group agreed with previously published reports stating that tuberosity osteotomy is technically demand- ing. They did conclude that late arthroplasty following failed primary treatment of complex proximal humerus fractures improves pain, ROM, and function. However, the results are inferior to proximal humerus fractures treated acutely with prosthetic arthroplasty.

When looking solely at the patients in Beredjiklian’s study who had proximal humerus malunions managed with prosthetic arthroplasty, 74% had satisfactory results.

Twenty-three of the 39 patients in his study were treated in this manner. The authors defined satisfactory by the presence of at least 90 degrees of active forward flexion, Ch07_p60-69.qxd 1/11/08 10:04 PM Page 67

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