Locking intramedullary nailing for the treatment of severely displaced two-part surgical neck fractures of the proximal humerus: factors influencing outcomes in elderly patients

doi:10.21203/rs.3.rs-1523591/v1

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Locking intramedullary nailing for the treatment of severely displaced two-part surgical neck fractures of the proximal humerus: factors influencing outcomes in elderly patients

https://doi.org/10.21203/rs.3.rs-1523591/v1

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Background: 2-part surgical neck fractures of the proximal humerus were treated using the locking intramedullary nail. The purpose of this study was to evaluate the clinical outcomes in elderly patients and to assess which factors are associated with the outcomes.

Methods: Forty seven patients who were 60 years of age or older were included in this study. All patients with severely displaced 2-part proximal humeral fractures were treated using a locking intramedullary nail. The average age of the patients was 72 years and the average follow-up period was 25 months. We assessed fracture healing, head-shaft angulation on radiograph, and complications. Japan Orthopaedic Association shoulder score was used to assess clinical outcomes. Statistical significance was determined using multiple regression analysis, Student t-test and Mann-Whitney U test.

Results: Radiographic fracture healing was obtained in all patients. The average head-shaft angulation was 129°. Complications included osteonecrosis in 1 patient. The average Japan Orthopaedic Association shoulder score was 87.3 points. In multiple regression analysis, head-shaft angulation was associated with significantly poor clinical outcomes (p =0.048). A lower head-shaft angulation was associated with significantly poor shoulder score especially in range of motion of the shoulder joint (p =0.012).

Conclusions: The technique of locking intramedullary nailing for elderly patients gives satisfactory results, and has a low rate of complications. Postoperatively, we should pay attention to varus angulation as it was associated with significantly poor shoulder function in the treatment of 2-part surgical neck fractures.

Trial registration: All patients were retrospectively registered in this study.

proximal humeral fractures

elderly patients

intramedullary nail

two-part fracture

varus angulation

varus deformity

Proximal humeral fractures are most often seen in elderly patients and are closely associated with osteoporosis [1, 2]. These fractures commonly occur due to minor trauma with most being minimally displaced (fracture displacement < 1 cm or fracture angulation < 45°). Non-operative treatment gives good functional outcomes in cases of minimally displaced fractures [3, 4]. For severely displaced fractures, however, surgery is considered the most effective treatment [5, 6]. We treated elderly patients with severely displaced 2-part surgical neck fractures of the proximal humerus using locking intramedullary nail. Although the elderly patients were treated non-operatively in cases of minimally displaced fractures, there have been few studies involving only elderly patients that demonstrated surgical treatment of severely displaced 2-part surgical neck fractures. Thus, the primary purpose of this study was to evaluate the clinical and radiographic outcomes of elderly patients with severely displaced 2-part surgical neck fractures, and the secondary purpose was to identify the factors that influence these outcomes.

This study approved by the institutional review board of Chukyo hospital. Between April 2003 and April 2020, elderly patients with severely displaced 2-part surgical neck fractures of the proximal humerus were treated using a locking intramedullary nail. The standard approach for elderly patients with minimally displaced fractures is non-operative treatment. When a fracture displacement was large or progressive, surgical treatment was considered. After reviewing the radiographs, severely displaced 2-part surgical neck fracture was defined as fracture displacement of 1cm or more (> 1cm) ,or angular deformity of 45° or more (> 45°) according to the Neer classification [7]. Clinical outcomes were assessed in fracture healing, range of motion (ROM) of the shoulder joint, and complications. We calculated the head-shaft angulation (HSA) on the anteroposterior radiograph at final follow-up by comparing a tangent to the articular surface with a line parallel to the long axis of the humeral shaft [8] (Fig. 1). The Japan Orthopaedic Association (JOA) shoulder score was used to assess the clinical outcomes. The score assesses pain (30 points), strength and endurance of the deltoid muscle (10 points), activity of daily living (10 points), ROM of the shoulder joint (30 points), radiographic evaluation (5 points), and shoulder stability (15 points). The JOA shoulder score was classified as excellent (91-100 points), good (81།90 points), fair (71།80 points), and poor (0།70 points) [9].

Surgical technique:

Under general anaesthesia, the patient was placed in the beach chair position on a radiolucent table. After an anterolateral skin incision of about 4 cm was made, we split the deltoid muscle from the insertion of the acromion distally. Closed reduction was obtained by indirect manipulation of the head fragment using a joystick or the kapanjii technique. Under image intensifier control, an entry hole for the nail was made using Kirschner wire at the apex of the humeral head. We used a T2® Proximal Humeral Nail (Stryker) for implantation. After making a longitudinal incision of the supraspinatus tendon, the nail was inserted without reaming at a level 2 to 3 mm below the cartilage. The proximal and distal locking screws were inserted depending on the fracture pattern and bone quality. The supraspinatus tendon and the deltoid muscle were repaired during wound closure. After the surgery, the patient’s arm was placed in a sling for 2 weeks. Pendulum and passive range of motion exercises were started carefully after 2 weeks. Active range of motion exercises were allowed after 5 weeks.

Statistical Analysis:

Descriptive statistics including means and standard deviations were calculated for all variables. Multiple regression analysis was performed to clarify factors correlated with the results of operative treatment using the JOA shoulder score considered as an independent variable. The dependent variables considered potential correlates of surgical outcomes in regression models included age, duration from injury to surgery, time needed for fracture healing, and HSA. The Student t-test and Mann-Whitney U test are used to compare differences between quantitative groups. A P value of 0.05 was considered significant for all correlation analyses. Statistical analysis was performed using Ekuseru-Toukei 2010 software (Social Survey Research Information Co., Ltd).

We retrospectively collected the data of 99 patients who were treated using a locking intramedullary nail. Seventeen patients were excluded because they were found to be under the age of 60 years, and 35 patients had insufficient data or an inadequate follow-up period of less than 12 months. We identified 47 patients who had complete clinical and radiological data. The patients included 13 males and 34 females with an average age of 72.1 years. The average duration from injury to surgery was 6.81 days. The average follow-up period was 24.7 months. Radiographic fracture healing was obtained in all patients. The average time needed for fracture healing was 3.89 months. The average ROM of the shoulder at final follow-up was 126° of flexion and 37.6° of external rotation. Complications included osteonecrosis in 1 patient. There were no deep wound infections and failure of fixation or any further neurological deficits. The average HSA was 129° and the average JOA shoulder score was 87.3 points; details are shown in Table 1. The average pain score was 26.9 points; the strength and endurance of the deltoid muscle was 9.04 points; activity of daily living was 9.32 points; ROM of the shoulder joint was 22.2 points; radiographic evaluation was 4.92 points and shoulder stability was 14.9 points. The final outcomes were excellent in 25 patients, good in 13, fair in 5 and poor in 4 patients. Multiple regression analysis show a lower HSA was associated with significantly poor clinical outcomes (p = 0.048; Table 2). Comparing the varus (HSA < 120°) and nonvarus (HSA ≧ 120°) groups, a lower HSA was associated with significantly poor JOA shoulder score especially in ROM of shoulder joint (p = 0.012;Table 3). Comparing the elderly group (75 years or Older) with the younger one (Younger Than 75years), there were no differences concerning JOA shoulder score, Pain, Strength and endurance, Radiographic evaluation, Shoulder stability, but there were significant differences in Activity of daily living, ROM of shoulder joint (p = 0.01, p = 0.048).

Non-operative treatment of minimally displaced proximal humeral fractures provided good fracture healing and satisfactory functional results [3, 4]. However, severely displaced fractures have occasionally had poor clinical results due to nonunion or osteonecrosis [2, 10]. Two-part surgical neck fractures account for 28% of all proximal humeral fractures [1]. Non-operative treatment of these fractures has often led to varus malunion [3, 5]. Several surgical techniques have been described in the literature, including percutaneous pinning, external fixation, intramedullary nailing, and plate fixation [5, 11, 12]. In elderly patients, poor fixation due to osteoporosis has been reported and surgical treatment did not lead to improvement [13]. Recently, the locking intramedullary nail and locking plate were used to overcome osteoporotic fractures in the proximal humerus [14–16]. Some studies have compared the locking intramedullary nail and the locking plate for the treatment of 2-part proximal fractures [17, 18]. Zhu et al. reported that the Constant-Murley score (including pain and shoulder motion) was not significantly different between the two techniques but duration of surgery, blood loss, and complications were significantly greater in plate fixation [17]. Gradle et al. compared the intramedullary locking nail and the locking plate in a prospective multicentre study [18]. They found no significant differences between the two techniques in Constant-Murley score or in complications. However, secondary fracture displacement and malunion were seen exclusively in patients after plate fixation. In the present study, we used the locking intramedullary nail for the treatment of severely displaced 2-part surgical neck fractures in elderly patients. Radiographic fracture healing was obtained in all patients. About 90% of these patients gained satisfactory functional results. Complications included osteonecrosis in 1 patient. We found that treatment using the locking intramedullary nail for elderly patients gives good results with a low rate of complications.

Our secondary purpose was to assess the factors influencing outcomes in elderly patients. In our study, varus angulation of the humeral head was associated with poor JOA shoulder score and showed restriction of shoulder movement. It is reported that there is a good correlation between the degree of varus malunion and the outcome [5]. Functional score was lower in the group with 25 to 34° varus angulation than in the group with 15 to 24° varus angulation [5]. In a biomechanical study, 20° varus angulation caused greater forces to accomplish early shoulder abduction, and 45° varus angulation significantly decreased the abduction efficiency of the supraspinatus tendon [19]. Our findings in this study support that varus angulation is associated with significantly poor shoulder function especially in ROM of shoulder joint. Three patients who had more than 30° of varus deformity (HSA < 110°) showed poor shoulder function.

We observed osteonecrosis in one patient after the surgical treatment. The patient had severe pain and severe restriction of shoulder movement. Postoperatively, re-displacement of the fracture site occurred, and bone support was lost on the medial side. The arterial blood supply of the proximal humerus consists of the anterior and posterior circumflex humeral arteries. We suppose that the distal fragment of the humerus disrupted the circumflex arterial blood supply causing the osteonecrosis. An analysis of other factors that affect outcome, the elderly group (75 years or Older) had significantly a lower activity of daily living. The elderly group had two patients with dementia and their clinical outcomes were poor. While follow-up radiographs of these patients showed fracture union and no deformity, both patients had severe restriction of shoulder movement. Their poor functional outcomes may be due to inadequate rehabilitation because they had been unable to follow the active range of motion exercise program.

There are limitations to this study. First, data were collected retrospectively. Selection bias may be a problem, as it is likely that the patients with symptoms were examined in the hospital, but the patients without symptoms were not followed up for a long time. Proximal humeral fracture in elderly patients is common, and a prospective study design would be appropriate to evaluate the factors influencing the outcomes. Secondly, the study population was small. Thirdly, rotation deformities of the shoulder were not assessed. In the future, another large-scale and 3-dimensional study should be performed to resolve these limitations.

The procedure of locking intramedullary nailing for the treatment of severely displaced 2-part surgical neck proximal humeral fractures in elderly patients gives satisfactory results and has a low rate of complications. Postoperative varus deformity is associated with significantly poor clinical outcomes.

ROM Range of motion

HSA Head-shaft angulation

JOA Japan Orthopaedic Association

Ethical approval and consent to participate

This study approved by the institutional review board of Chukyo hospital. Written consent was obtained from each participant.

Consent for publication

Not applicable

Availability of data and materials

The datasets used during the current study are available from the corresponding author on reasonable request.

Competing Interests

The authors declare that they have no competing interests.

Funding

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.

Author Contributions

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by KA, SH, YA. The first draft of the manuscript was written by KA and HH commented on previous versions of the manuscript.

Acknowledgements

I am deeply grateful to James Curley for his assistance in writing the manuscript and encouraging comments.

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Tables 1 to 3 are available in the Supplementary Files section.

TableproximalhumeralfrBMC.doc

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Editorial decision: Reject after review
23 Jun, 2022
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20 May, 2022
Reviewers invited by journal
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Editor invited by journal
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Editor assigned by journal
13 Apr, 2022
First submitted to journal
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You are reading this latest preprint version

Locking intramedullary nailing for the treatment of severely displaced two-part surgical neck fractures of the proximal humerus: factors influencing outcomes in elderly patients

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Abstract

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Background

Methods

Statistical Analysis:

Results

Discussion

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Abbreviations

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References

Tables

Supplementary Files

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