A Retrospective Study in the Treatment of a 2-Part Greater Tuberosity Fracture Using the F3 Biomet Plate

Proximal humeral fractures are clinically common, and 13% to 33% of such fractures involve greater tuberosity fractures, which are frequently caused by high-energy trauma.¹ A humeral greater tuberosity fracture is a periarticular fracture. A displaced tuberosity lying under the acromion provides a bony block to abduction. In addition, a fragment may extend into the bicipital groove or bicipital sulcus of the humerus, affecting the biceps tendon indirectly, whereas superior displacement leads to malfunction of the rotator cuff and impingement.² Inappropriate treatment cannot prevent further displacement and secondary decrease of shoulder function, and may result in shoulder dysfunction.³ When the displacement of the greater tuberosity is more than 5 mm or the angular displacement is greater than 45°, surgical reduction and internal fixation are considered for treatment.⁴ In recent years, a variety of surgical devices and techniques for this type of fracture have been reported. Flatow et al⁵ reported a series of 12 patients with displaced isolated greater tuberosity fractures who were treated with open reduction and internal fixation (ORIF) using nonabsorbable sutures. Park et al⁶ retrospectively reviewed 13 displaced isolated greater tuberosity fractures treated with suture fixation. All patients obtained satisfactory results. Other authors have reported similarly promising results using closed reduction and percutaneous fixation techniques.^7,8 With further development of arthroscopy techniques, some displaced isolated greater tuberosity fractures can be treated by the arthroscopic fixation, with good results reported in several small series.^9–12 However, the selection of the implant remains controversial, and no method has been proven as the ideal choice.

Materials and Methods

Study population

This was a retrospective study approved by our Institutional Review Board. Between September 2010 and January 2014, a total of 27 patients with 2-part displaced humeral greater tuberosity fractures were treated in the hospital. All of the included patients provided consent to participate in any reviews in the future. Our exclusion criteria include: (1) pathologic fracture or refracture; (2) old fracture or open fracture; (3) multiple fracture, concomitant plexus, and/or nerve injuries; (4) patients with existing systemic disease that has a relevant effect on the fracture healing, such as paraplegia, multiple sclerosis, and relevant neurologic disorders; and (5) patients who were lost to follow-up. After the selection based on the exclusion criteria, a total of 23 patients were selected in this study and divided into 2 groups according to the therapeutic method. Eleven patients were surgically treated by ORIF with use of an F3 Biomet plate, and 12 patients underwent nonsurgical treatment because they refused to undergo the surgery—with consideration given to such factors as bad state of health, lack of compliance, personal economic reasons, etc—despite fragment displacement greater than 5 mm. All of the patients had fresh closed fractures (time between injury and treatment was less than 7 days), and were confirmed to have isolated greater tuberosity fractures on X-ray. All fractures were classified according to the morphology. The patient demographics and fracture characteristics are summarized in Table 1.

Table 1  Patient demographics

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Surgical technique

Eleven patients underwent ORIF with the use of an F3 plate under general anesthesia. The patients were placed in the supine position on a radiolucent operating table. A rubber cushion was placed under the affected shoulder, and the injured arm was abducted by a surgical assistant. A longitudinal deltoid-splitting approach was used, and the incision was 4 to 5 cm long (Fig. 1B). The space between the anterior part and intermediate part of the deltoid was located by identifying the adipose and fiber texture. There were fewer blood vessels in this area. A blunt dissection was used to separate the muscle at 4 to 5 cm from the apex to the distal point of the acromion, and the bursa subdeltoidea was split to expose the fracture. To protect the axillary nerve, the nerve was identified by placing an index finger in the bursa subdeltoidea, and its course was marked on the skin (Fig. 1A). The reduction was performed through traction and manipulation under direct observation (Fig. 1C). If necessary, Kirschner wires were used to temporarily fix the fracture fragments. During the operation, a Y-type F3 (Biomet, Warsaw, Indiana) high-flexible mini-locking plate was shaped and bent according to the specific fracture condition. The plate was placed tightly around the greater tuberosity fragment, ensuring that the proximal fragment was fixed with at least 3 screws. In addition, the distal side of the F3 plate was fixed by 3 screws on the metaphysis. Subsequently, we examined by visual inspection whether the rotator cuff was torn or injured, and if necessary, the rotator cuff injury was sutured and repaired (Fig. 1D). The shoulder was moved in all directions to confirm reliable fixation of the greater tuberosity. The incision was closed after a radiographic examination by C-arms showing a satisfactory reduction. The chief operator was the same for all 11 patients' surgeries.

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Results

X-rays of the patients in both groups showed that the fractures achieved union after the 1-year follow-up. All 11 patients in the F3 group (Fig. 2B and 2C) successfully completed the operation. The mean operation time was 57 minutes (range, 40–75 minutes), and the mean intraoperative blood loss was 86 mL (range, 60–110 mL). Only 1 patient underwent a rotator cuff tendon repair. All of the operative incisions achieved primary healing, and there were no infections, internal fixation breaks or loosening, fracture fragment displacements, shoulder impingement syndromes, or other complications (Fig. 2D). The 12 patients who underwent nonsurgical treatment of displaced greater tuberosity fractures were evaluated as the control group. The X-rays revealed that fractures healed without any signs of nonunion. But the fragments of 8 patients still stayed at the original displacements. Although 1 patient had small heterotopic bone fragments beneath the acromion, he chose not to undergo the surgery because the relevant influence on the shoulder function was acceptable to him. Another patient showed further superior displacement of the greater tuberosity. He elected not to undergo further revision surgery because he had little pain.

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During the 1-year follow up, the mean Constant score in the F3 group was 92.73 (SD, 2.05), whereas that in the nonsurgical group was 71.42 (SD, 9.45; Fig. 3). The mean DASH score was 11.45 (SD, 4.06) in the F3 group and 43.75 (SD, 14.17) in the nonsurgical group (Fig. 4). The operative details and clinical evaluations of the patients in the F3 group are summarized in Table 2. Statistical analyses revealed that the patients in the surgical group had significantly better functional outcomes than those in the nonsurgical group (Table 3).

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Table 2  Synopsis of operation and clinical evaluation of patients in the F3 group

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Table 3  Surgical and nonsurgical clinical scores

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Discussion

The results of our study revealed good functional and radiographic outcomes after ORIF of displaced greater tuberosity fractures using an F3 plate. Platzer et al⁷ retrospectively analyzed the functional and radiographic results of 52 patients with operative treatment of displaced greater tuberosity fractures at a mean time of 5.5 years after injury. Those results were compared with the functional and radiographic outcomes of 9 patients with equal injuries who were treated nonsurgically. They found that the patients with nonsurgical treatment showed significantly worse results. As the end point of the supraspinatus muscle, infraspinatus muscle, and teres minor muscle, the humeral greater tuberosity plays a significant role in maintaining shoulder function and activity. Because the different muscles have uneven traction effects after a fracture, the humeral greater tuberosity is prone to displacement. This separation may cause nonunion of the greater tuberosity, affecting the rotator cuff and brachial glenoid articular activity. Surgical treatment should be undertaken for fractures with a displacement larger than 1 cm.⁴ Meanwhile, fractures displaced between 0.5 and 1 cm fall into a gray zone for treatment. Some authors agree that posterosuperior displacement leads to significant symptoms of subacromial impingement, which should be treated with surgery.^3,15 Park et al¹⁶ believed that fractures with a displacement of only 3 mm should be corrected in heavy laborers and athletes who need to engage in overhead activities.

Clinically, the most common surgical methods for this type of fracture are open reduction locking-plate internal fixation, cannulated screw fixation, and bone-anchored suturing. These methods have some disadvantages. Lill et al¹⁷ stated that a traditional proximal humerus plate has a high degree of contact with the bone, which affects the periosteal blood supply and is not conducive to fracture healing. The larger the implanted plate, the higher the chances are of secondary impingement syndrome.^18,19 The plate may also affect the biceps tendon, because the continuous friction can cause biceps injury and even rupture. Braunstein et al²⁰ reported that the fixation strength and compression strength of cannulated screws are limited, such that the screws can easily become loose. Platzer et al³ stated that a secondary loss of reduction, which could be found in 17% of patients, also increases the risk of subacromial impingement. In addition, the greater tuberosity of the humerus is mainly cancellous bone, and for elderly patients with osteoporosis, fracture fragments are prone to displacement, again because of the traction on the muscles after the operation. Hollow lag screws are thick, and the drilling and tightening of the screws tend to cause a secondary injury to the fractured bone, whereas the washers for the screws can result in secondary impingement syndrome.²¹ Bone-anchored suturing is also widely used in clinical practice. This technique fixes the tendon and bone interface, allows patients to avoid allergies to the implant, and does not require implant removal. Dimakopoulos et al¹⁵ evaluated the long-term functional and radiographic results of transosseous suture fixation in 188 patients, of whom 56 had 2-part fractures of the greater tuberosity. All of these patients showed bony union within 4 months. At the time of the final evaluation, the mean Constant score was 91 points. However, suturing would further diminish the stability of the fragments; in addition, if a greater tuberosity fracture has multiple fragments, it is not conductive to fixation of the fractured bone fragments.⁴

The F3 Biomet plate (Fig. 2A) was initially used for fixation of fractures of the phalanx and other small long bones. We applied these mini-plates to the treatment of isolated humeral greater tuberosity fractures. Gruson et al⁴ stated that the choice of method was dependent not only on the fracture type and characteristics (displacement, location, comminution), but also on a multitude of patient-related factors (age, comorbidities, preinjury level of function, local bone quality). We believe that the F3 plate is appropriate for displaced greater tuberosity fractures if the patient can tolerate the operation.

The mini-locking plate can sufficiently cover fracture fragments, and the locking screws can be fixed at angles even in osteoporotic fracture fragments, yielding good tensile strength and anchor force to ensure the fixation strength of the fractured fragments, such that displacement cannot easily occur. Gaudelli et al²² reported that locking plate fixation provided stronger and stiffer biomechanical fixation than tension bands and double-row suture bridges for split-type greater tuberosity fractures. Compared with nonsurgical management, patients can perform shoulder function exercises earlier. For treatment of a comminuted fracture, we use locking screws to fix the relatively large displacement fragments if possible, and bundle or suture small fragments along with the fence structure of the implant. If the fragments are too small to be fixed by a locking screw, we cover these small fragments with the plate. The frictional force extruded between the fragments and the steel plate can also contribute to the stability of the fracture fragments. In addition, the fence structure can facilitate the repair of the rotator cuff if necessary and provide more reliable stability. The plate can be shaped inside of the body during the operation, which facilitates maximal fixation of the plate to the complicated bone surface. The plate has multiple drilled holes, which allow the pressure to be distributed to each screw hole.

In the present study, the F3 Biomet plate provided reliable stability, and satisfactory functional results were obtained. All fractures healed within 9 to 14 weeks. There were no infections, internal fixation breaks or loosening, fracture fragment displacements, shoulder impingement syndromes, or other complications. Recently, Schöffl et al²³ used a small Bamberg plate cut from a calcaneus plate to treat greater tuberosity fractures. Although a small number of cases were presented, the results were better than those in the studies by Szyszkowitz et al²⁴ and Dimakopoulos et al.¹⁵ Chen et al²⁵ treated greater tuberosity fractures using an AO X-shaped midfoot locking plate that was originally designed for midfoot fractures. Nineteen patients with displaced fractures of the greater tuberosity were treated surgically by ORIF using the AO X-shaped midfoot locking plate. All fractures healed without associated complications. At the last follow-up, the mean Constant score was 90.6 (SD, 4.0) points. These plates performed functions similar to those of the F3 Biomet plate. However, the F3 plate can be shaped and cut inside of the body, thereby facilitating maximal fixation of the complicated bone surface. Nevertheless, the present study also has some limitations, such as having few cases, short follow-up time, etc. Further studies are therefore required to fully evaluate the role of the F3 Biomet plate for displaced humeral greater tuberosity fractures.