Proximal humerus fractures (PHFs) account for approximately 5% of all fractures and are increasing in frequency as the population ages.1 Although most PHFs can be treated non-surgically, displaced PHFs are difficult to treat, especially when the fracture involves medial column comminution.2 Locking plate fixation has become an important technique for the surgical treatment of PHF,3,4 but the rate of postoperative complications is relatively high.5,6 The most frequent complications are screw cutout with intra-articular perforation and varus collapse.7 Several studies have identified restoration of the medial column as an important factor in reducing the occurrence of complications, especially varus collapse of the humeral head and loss of fixation, after locking plate treatment of PHF in which the medial column is comminuted.7–9 Gardner et al10 first described the use of an intramedullary fibular allograft for PHF to restore the medial column. Their clinical experience showed healing in 7 cases without loss of reduction or fixation stability. Subsequently, many studies have reported good clinical results with the use of fibular allografts with locking plates for PHF fixation.11–16 However, few clinical studies have compared the use of a locking plate combined with fibular allograft augmentation with the use of a locking plate alone to treat PHF with medial comminution. The goal of this study was to evaluate the role of endosteal fibular allografts in the treatment of medial column comminuted PHF with a locking plate. The authors hypothesized that the use of a locking plate in combination with fibular allograft augmentation to treat PHFs with medial column comminution would result in fewer postoperative complications and better functional outcomes than fixation with a locking plate alone.
Materials and Methods
After institutional review board approval was obtained, the authors retrospectively reviewed 63 patients (21 men and 42 women) who had displaced PHF in which the medial column was comminuted. All of the patients were treated with a locking plate alone or in combination with endosteal fibular strut allograft augmentation at Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China, between January 2013 and May 2017. The authors obtained informed consent from all participants. Average patient age was 63.4 years (range, 34–89 years). Of these patients, 41 were treated with a locking plate combined with endosteal fibular strut allograft augmentation. Average age of this group of patients was 64.1 years (range, 34–89 years); 12 were men and 29 were women. Another 22 patients were treated with a locking plate alone. Average age of these patients was 62.2 years (range, 35–83 years); 9 were men and 13 were women. The authors evaluated the fracture pattern according to the Neer classification with preoperative shoulder radiographs and computed tomography scan.17 According to the Neer classification, there were 6 two-part, 19 three-part, and 16 four-part fractures in the group of patients who were treated with a locking plate and an endosteal fibular allograft, and there were 3 two-part, 10 three-part, and 9 four-part fractures in the group of patients who were treated with a locking plate alone. All patients had a minimum follow-up of 12 months, and the average follow-up was 16.3 months (range, 12–36 months). The neck-shaft angles were measured with anteroposterior radiographs. The neck-shaft angle is the angle between the line perpendicular to the base of the anatomic neck of the humerus and the centerline of the humeral shaft (Figure 1).18 Gardner et al10 described the change in humeral head height as a determinant of maintenance of reduction. Humeral head height was obtained by drawing two lines that were perpendicular to the shaft of the plate; one line was placed at the top edge of the plate, and the other was placed at the top edge of the humeral head. The distance between these two lines was measured and defined as the humeral head height (Figure 2). Postoperative complications, including screw perforation into the glenohumeral articular surface, fracture non-union or malunion, infection, subacromial impingement, and avascular necrosis of the humeral head, were reviewed, and functional outcomes were evaluated with the Constant-Murley score.
Anteroposterior radiograph of the shoulder at 12 months postoperatively showing the neck-shaft angle defined by the angle sub-tended by the centerline of the shaft and a perpendicular line from the superior to the inferior border of the articular surface. Line a refers to the axial line of the humeral shaft. Line b refers to the line between the superior and inferior borders of the articular surface of the humeral head. Line c is perpendicular to line b and goes through the center of the humeral head.
Anteroposterior radiograph of the shoulder at 6 months postoperatively showing the humeral head height defined as the distance between the uppermost head of the humerus and the uppermost edge of the plate. Two lines were drawn running perpendicular to the shaft of the plate (line a); one was placed at the top edge of the plate (line b), and the other was placed at the superior edge of the humeral head (line c). The distance between these two lines was measured and designated as the head height.
Postoperatively, all shoulders were immobilized with a sling for 4 to 6 weeks. All patients were allowed elbow, wrist, and hand range of motion exercises from the second postoperative day. Passive shoulder range of motion was allowed from 2 to 6 weeks postoperatively, depending on the fracture type and degree of medial comminution. Active and resisted exercises were allowed at approximately 6 to 12 weeks, when fracture healing was observed radiographically and clinically.
Overall summary statistics were calculated as mean and standard deviation for continuous variables and as frequency and percentage for categorical variables. Statistical analysis was performed with SPSS version 22.0 software (IBM Corp, Armonk, New York), and Excel 2016 (Microsoft Corp, Redmond, Washington). Data were analyzed between the 2 groups with independent samples t tests and chi-square tests. P<.05 was considered statistically significant.
Demographic data are shown in Table 1. After an average follow-up of 16.3 months, all of the fractures healed. In the group of patients who were treated with locking plates with fibular allografts, no patients showed changes in the neck-shaft angle of more than 10°, and mean change was 3.3° (range, 0.1°–8.1°). Only 1 patient (2.4%) showed a change in humeral head height of more than 3 mm, and mean change was 1.1 mm (range, 0–3.6 mm). In addition, 3 patients (7.3%) had screw perforation of the articular surface. In the group of patients who were treated with locking plates alone, 3 patients (13.6%) showed a change in the neck-shaft angle of more than 10°, and mean change was 7.6° (range, 1.2°–16.5°). Changes of humeral head height of more than 3 mm were observed in 6 patients (27.3%), and mean change was 3.4 mm (range, 0.3–7.6 mm). In addition, 6 patients (27.3%) had intraarticular screw perforation, and of these patients, 1 (4.5%) had humeral head osteonecrosis. Statistically significant differences were seen between the 2 groups in the change in neck-shaft angle and humeral head height (P<.001) and in the overall incidence of complications (P<.05). However, no statistically significant difference was seen in Constant-Murley score (83.7 vs 79.1, P>.05; Table 2; Figure 3).
Comparison of Radiographic and Functional Outcomes
An 83-year-old woman had a Neer 3-part proximal humerus fracture. Preoperative anteroposterior shoulder radiograph (A) and 3-dimensional computed tomography reconstruction (B, C) showed a comminuted fracture at the proximal humerus with medial cortical disruption. Anteroposterior radiograph obtained on the first day postoperatively showed good medial and humeral head support by the endosteal strut allograft and locking plate (D). Anteroposterior (E), scapular lateral (F), and axillary lateral (G) radiographs obtained 12 months postoperatively showed that the neck-shaft angle and humeral head height were maintained and the fracture had healed.
Although locking plates offer many advantages over traditional plating, high complication rates have been reported, and varus collapse and screw perforation resulting in revision surgery are particularly common.5,6 Some studies have shown the importance of the integrity and stability of the medial column in the treatment of PHF.7,9 Lee and Shin9 concluded that a lack of medial column support is among the most important prognostic factors leading to poor outcomes.
Gardner et al7 studied 35 patients who underwent locked plating surgery for PHF. Of these patients, 18 had adequate mechanical medial support (+MS group), and the remaining 17 patients did not (-MS group). In the +MS group, average loss of humeral head height was 1.2 mm, and 1 case of articular screw penetration occurred. In the -MS group, loss of humeral height averaged 5.8 mm (P<.001), and in 5 cases, screw penetration of the articular surface occurred (29%; P=.02). The authors concluded that achieving mechanical support of the inferomedial region of the proximal humerus is important for maintaining fracture reduction. Gardner et al10 reported the first clinical use of fibular strut allografts with locking plates to treat PHF in 2008. This study showed satisfactory results in that all 7 patients healed without loss of reduction or fixation stability.10 Later, Neviaser et al15 reported a series of 38 patients who had displaced PHF and were treated with locking plate fixation and an endosteal fibular allograft. The authors found that none of the patients had complete osteonecrosis (0%), only 1 patient (2.8%) had partial osteonecrosis, 1 patient had a reduction loss (2.6%), and no patients had screw cutout (0%). In the current study, the authors found that 3 patients (7.3%) who were treated with a locking plate with a fibular allograft had screw perforation of the articular surface. Of the patients who were treated with a locking plate alone, 6 patients (27.3%) had intra-articular screw perforation. Among these patients, 1 (4.5%) had humeral head osteonecrosis (P<.05).
Recently, several similar clinical studies showed that the use of an endosteal strut allograft to repair PHF can allow reconstruction of the medial column support with good results.11,14,16 One study19 compared the radiologic outcomes of fixation with a locking plate only with those of fixation with a locking plate with an endosteal strut allograft in the treatment of comminuted PHF. Among the patients treated with a locking plate only, more patients had changes in the neck-shaft angle of greater than 5° and changes in humeral head height of more than 3 mm compared with the patients who were treated with a locking plate with an endosteal strut allograft (P<.001).
In the current study, among patients who were treated with a locking plate alone, 3 patients (of 22) had changes in the neck-shaft angle of more than 10°, and 6 patients had changes in humeral head height of more than 3 mm. In contrast, in the group of patients who were treated with a locking plate with a fibular allograft, no patient had a change in the neck-shaft angle of more than 10°, and 1 patient (2.4%) showed a change in humeral head height of more than 3 mm. The differences in both of these variables were statistically significant (P<.001).
Several biomechanical studies found that locking plate fixation combined with an intramedullary fibular allograft increases the overall stiffness of the construct and reduces migration of the humeral head fragment compared with fixation with a locking plate alone.20–22 More recently, Hinds et al12 reported the outcomes of PHF treated with a locking plate in combination with an endosteal fibular allograft in geriatric patients compared with nongeriatric patients. These authors found similar clinical outcomes between the 2 groups and concluded that the use of the endosteal fibular allograft resulted in excellent outcomes, regardless of patient age. Little et al13 examined the influence of preoperative coronal plane deformity on clinical outcomes after PHF fixation with endosteal augmentation. These authors found no significant differences in complication rates or radiographic or clinical outcomes between patients who had preoperative varus coronal displacement compared with valgus coronal displacement, and they believed that the equivalent outcomes may have been attributable to fibular strut augmentation.
Although intramedullary fibular allografts can help to maintain reduction and decrease postoperative complications after locking plate fixation for PHF, there are some points that should be mentioned. First, the use of an extrafibular allograft increases patient cost; therefore, the surgeon should consider the patient's economic situation. Second, the use of an allograft may increase the risk of infection and disease transmission, but these risks can be reduced through aseptic management during allograft processing. Third, for some patients, this procedure must be used with caution, and the authors recommend its use for patients with PHF in which the medial column is severely comminuted.
There were some limitations to this research. First, this was a retrospective case series with a relatively small number of patients. Minimum follow-up was only 12 months, and with this limited follow-up, the authors recognize that avascular necrosis could occur in the future. Further study is needed to examine functional outcomes and postoperative complications.
The use of a locking plate combined with intramedullary fibular allograft augmentation can help to maintain reduction and reduce postoperative complications in the treatment of PHF complicated by medial column comminution.
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|Variable||Locking Plate With Fibular Allograft||Locking Plate Alone|
|Age, mean (range), y||64.1 (34–89)||64.1 (35–83)|
|Affected shoulder, right/left, No.||20/21||14/8|
|Injury mechanism, No.|
| Fall or trip from standing height||33||15|
| Fall down stairs or from a height||5||5|
| Motorcycle accident||3||2|
|Time from injury to surgery, mean (range), d||3.6 (2–16)||3.8 (2–12)|
|Follow-up, mean, mo||19.3||16.3|
|Neer classification, No.|
Comparison of Radiographic and Functional Outcomes
|Variable||Locking Plate With Fibular Allograft||Locking Plate Alone||P|
|Change in neck-shaft angle, mean±SD (range)||3.3°±2.2° (0.1°–8.1°)||7.6°±4.2° (1.2°–16.5°)||<.001|
|Change in humeral head height, mean±SD (range), mm||1.1±1.1 (0–3.6)||3.4±2.0 (0.3–7.6)||<.001|
|Complications, No. of patients||3 (7.3%)||6 (27.3%)||<.05|
|Constant-Murley score, mean±SD (range)||83.7±8.6 (62–100)||79.1±8.9 (56–100)||>.05|