Electrophysiological assessment of the deltoid muscle after minimally invasive treatment of proximal humerus fractures - a clinical observation

The use of medial support screw was associated with axillary nerve injury after plate fixation of proximal humeral fracture using minimal invasive deltoid-splitting approach

BACKGROUND

The purpose of this study was to evaluate the incidence and risk factors for axillary nerve injury after plate fixation of humeral fractures using minimal invasive deltoid-splitting approach. We hypothesized that the use of medial support screw (MSS) would be associated with the outcome of axillary nerve injury.

METHODS

This study retrospectively evaluated consecutive 32 patients who underwent surgical treatments for proximal or midshaft humeral fractures. Of them, we included 26 patients who were examined by electromyography/nerve conduction (EMG/NCV) study at 3-4 weeks postoperatively. We excluded 6 patients because two of them were not compliant to EMG/NCV and the remaining two died due to unrelated medical illness. Outcome assessments included pain, functional scores, range of motion, and radiographic results.

RESULTS

There were 8 male and 18 female patients with mean age of 67 ± 15 years. Mean duration of follow-up period was 31 ± 11 months. The mean time to EMG/NCS after surgery was 3.5 ± 0.6 weeks. EMG/NCS examinations revealed incomplete axillary nerve injury in 8 patients (31%) without complete nerve injury. Active forward elevation at 3 months postoperatively was significantly lower in patients with axillary nerve injury than in those without it (99° ± 12 and 123° ± 37, respectively, p = 0.047), although final clinical outcomes were not different. At surgery, MSS was used in 17 patients (65%), and 8 of them were associated with nerve injury. The use of MSS was only correlated with the outcome of axillary nerve injury, because the axillary nerve injury developed only in MSS group (p = 0.047). The MMT grade 4 in abduction strength was more common in patients with axillary nerve injury than in those without (p = 0.037).

CONCLUSIONS

Axillary nerve injury was a concern after plate fixation of proximal humeral fracture using minimal invasive deltoid-splitting approach. The use of medial support screw to improve the stability could increase a risk of axillary nerve injury when used with this approach.

Functional results of deltoid split minimally invasive osteosynthesis for neer type 3 proximal humerus fractures

We aimed to evaluate the short-term functional and radiological outcomes of the minimally invasive fixation of three-part proximal humerus fractures without using calcar screws. Twenty patients were treated with the minimally invasive approach using locking plate-screws. The relationship between the cephalo-diaphyseal angles and the functional outcomes were evaluated. The mean follow-up time were 22.7 months. The mean Constant-Murley score of the patients was 83.7. The modified Constant-Murley score was excellent in 16 and good in four patients. A statistically significant difference was detected between cephalo-diaphyseal angles. Osteosynthesis with minimally invasive plate-screw and deltoid splitting application is encouraging with its satisfactory results in three-part fractures of the humerus; however, the total complication rate of 35% should not be ignored. In addition, in order to prevent a significant varus collapse and angular loss, the fracture subgroups should be studied in detail and additional measures should be taken based on the fracture type.

Is there any clinical significance of axillary nerve electrophysiological changes in the deltoid split approach?

Purpose

The clinical effects of axillary nerve injury in the deltoid splitting approach are controversial. This study investigated the axillary nerve function with clinical and electrophysiologically in proximal humeral fracture patients with internal fixation using the deltoid split approach. We also aimed to investigate the effects of this damage on deltoid muscle volume and discuss the effects of volumetric changes and nerve damage on patients' clinical outcomes.

Methods

study designed prospectively with 25 consecutive patients who received open reduction and internal fixation of proximal humerus fracture through a deltoid splitting approach. We performed clinical, electrophysiological, and radiological examinations during minimum follow-up time of 24 months. Electrophysiological examination comprised electromyoneurography (EMNG). Functional results followed by Constant-Murley and Disabilities of the Arm, Shoulder, and Hand scores. Deltoid volumes were evaluated with magnetic resonance imaging.

Results

Twenty-five patients operated on with open reduction internal fixation were prospectively observed. In the EMNG measurements of the patients on the 45th postoperative day, partial degeneration was observed in the anterior part of the axillary nerve in all cases (100%). In the control EMNG measurements performed at the 12th month, normal values were obtained for 15 (60%) of the patients, while findings of ongoing regeneration were detected for 10 (40%) of the patients and normal values at all patients at the 24th month. The difference between abnormal and normal EMNG groups' on 12th month Constant-Murley scores was not statistically significant in any period. Only anterior muscle thickness was statistically higher in the normal patient group than with abnormal EMNG results.

Conclusions

In proximal humeral fractures treated with the deltoid split approach, there may be iatrogenic damage of the anterior branch of the axillary nerve. Axillary nerve damage does not affect the patients' clinical scores in the early and mid-terms.

Level of evidence

LEVEL III.

How Many Proximal Screws Are Needed for a Stable Proximal Humerus Fracture Fixation?

Purpose

This biomechanical study investigates the optimal number of proximal screws for stable fixation of a 2-part proximal humerus fracture model with a locking plate.

Methods

Twenty-four proximal humerus fracture models were included in the study. An unstable 2-part fracture was created and fixed by a locking plate. Cyclic loading and load-to-failure tests were used for the following 4 groups based on the number of screws used: 4-screw, 6-screw, 7-screw, and 9-screw groups. Interfragmentary gaps were measured following cyclic loading and compared. Consequently, the load to failure, maximum displacement, stiffness, and mode of failure at failure point were compared.

Results

The interfragmentary gaps for the 4-screw, 6-screw, 7-screw, and 9-screw groups were significantly reduced by 0.24 ± 0.09 mm, 0.08 ± 0.06 mm, 0.05 ± 0.01 mm, and 0.03 ± 0.01 mm following 1000 cyclic loading, respectively. The loads to failure were significantly different between the groups with the 7-screw group showing the highest load to failure. The stiffness of the 7-screw group was superior compared with the 6-screw, 9-screw, and 4-screw groups. The maximum displacement before failure showed a significant difference between the comparative groups with the 4-screw group having the lowest value. The 7-screw group had the least structural failure rate (33.3%).

Conclusion

At least 7 screws would be optimal for proximal fragment fixation of proximal humerus fractures with medial comminution to minimize secondary varus collapse or fixation failure.

Level of Evidence

Basic science study.

Effect of surgical approaches on deltoid innervation and clinical outcomes in the treatment of proximal humeral fractures

Objectives

This study aims to investigate the effects of deltopectoral and anterolateral acromial approaches commonly used in open reduction-internal fixation of proximal humeral fractures on the clinical outcomes, and axillary nerve damage through electrophysiological assessment.

Patients and methods

Forty-eight patients (22 males, 26 females; mean age 47.9±13.2 years; range, 22 to 73 years) diagnosed with Arbeitsgemeinschaft für Osteosynthesefragen (AO)/Orthopaedic Trauma Association (OTA) type 11 proximal humeral fractures who underwent osteosynthesis with anatomical locking plates in our hospital between January 2015 and June 2016 were prospectively examined. The patients were divided into two groups according to either the deltopectoral or anterolateral deltoid-split surgical approach used. Clinical outcomes were evaluated using the Disabilities of the Arm, Shoulder, and Hand (DASH) scores and Constant-Murley scores (CMS) obtained at three- and 12-month follow-up visits. Needle electromyography (EMG) was performed for the electrophysiological assessment of the deltoid muscle.

Results

There were no significant differences between the groups in terms of demographic data, follow-up times, and complications. DASH scores and CMS obtained postoperatively at three months (p=0.327 and p=0.531, respectively) and 12 months (p=0.324 and p=0.648, respectively) revealed no significant differences. In addition, the two groups did not significantly differ with respect to the presence of EMG abnormalities (p=0.792). Avascular necrosis of the humeral head was detected in only two patients from the deltopectoral group.

Conclusion

Deltopectoral and anterolateral approaches do not differ regarding the presence of postoperative EMG abnormalities and functional outcomes. Surgeons can thus adopt either approach. However, dissection without damaging the soft tissue should be performed in both approaches.

Axillary nerve lesions after open reduction and internal fixation of proximal humeral fractures through an extended lateral deltoid-split approach: electrophysiological findings

BACKGROUND

Axillary nerve injuries after shoulder surgery are rare. In most studies, the frequency of injury is usually determined using clinical examinations, but results from intraoperative neuromonitoring studies have revealed higher than expected rates. Few studies have investigated this topic. Our aim was to determine the frequency of axillary nerve lesions after open reduction and internal fixation of proximal humeral fractures by using electrophysiological assessments and to provide a review of the relevant literature.

METHODS

This was a retrospective cohort study of 76 consecutive patients who received open reduction and internal fixation of a proximal humeral fracture using a locking plate through a deltoid-splitting approach. We performed a clinical and electrophysiological examination at a minimum follow-up time of 12 months. Functional results were assessed according to the Constant-Murley and Disabilities of the Arm, Shoulder and Hand scores. Electrophysiological examinations comprised electromyography, electroneurography, and motor and somatosensory evoked potentials. The main outcome was the frequency of axillary nerve lesions.

RESULTS

Forty patients were monitored for an average of 28 months. The mean raw Constant-Murley score was 61 points, the age- and gender-adjusted score was 71%, and the mean Disabilities of the Arm, Shoulder and Hand score was 33 points. Neurapraxia occurred in 1 patient, axonotmesis with incomplete reinnervation occurred in 3, and complete reinnervation occurred in 3. The latter group was classified as having a temporary axillary nerve lesion.

CONCLUSIONS

The 10% rate of permanent axillary nerve lesions in our cohort is higher than expected based on the clinical examination. Electrophysiological assessment is therefore more appropriate to detect axillary nerve injuries.

Minimally invasive polyaxial locking plate osteosynthesis for 3-4 part proximal humeral fractures: our institutional experience

INTRODUCTION

The objectives of this study were to describe the surgical technique of fixation of 3-4 part proximal humeral fractures with polyaxial locking plates utilising a minimally invasive approach and to evaluate the accuracy of reduction and stability of fixation.

PATIENTS AND METHODS

We retrospectively reviewed 90 patients. Fractures were classified according to the Neer classification system. Different radiological parameters were measured to assess the quality of reduction and the stability of fixation. Complications and clinical outcomes were evaluated after one year of minimum follow up.

RESULTS

There were 76 women and 14 men, with a mean age of 67.4years ±13 (range, 29-85). There were 60 3-part and 30 4-part fractures. Frozen cancellous allograft was used in 30 cases (33.3%). All fractures progressed to union and at one year follow up, the mean Constant score was 79.6±12(range, 62-100). Mean forward flexion, abduction, external rotation and internal rotation were 155°, 148°, 39° and vertebra Dorsal 8, respectively. Complications were noted in seven patients while the postoperative "head-diaphysis angle", "greater tuberosity height" and "medial metaphysis reconstruction" were close to the anatomical parameters; no significant differences were noted at one year radiological follow up.

CONCLUSION

Reliable and stable fixation can be expected with the use of polyaxial locking plate through a minimally invasive approach for the treatment of 3-4 part proximal humeral fractures. Satisfactory functional results for this procedure can be obtained.

Dynamic contrast-enhanced ultrasound (CEUS) after open and minimally invasive locked plating of proximal humerus fractures

INTRODUCTION

Closed reduction and locked plate fixation of proximal humerus fractures with the minimally invasive deltoid-splitting approach intends to minimize soft tissue damage although axillary nerve injury has been reported. The aim of this study was to assess the deltoid muscle perfusion with dynamic contrast-enhanced ultrasound (CEUS) as novel technique and evaluate its relation to the functional and neurologic outcome after open (ORIF) and minimally invasive (MIPO) fracture fixation.

PATIENTS AND METHODS

50 patients, 30 with deltopectoral ORIF and 20 with deltoid-splitting MIPO approach were examined 6-49 months after surgery. Only patients with a healthy, contralateral shoulder were selected. Shoulder function, satisfaction as well as psychosocial outcome were assessed with established scores (Constant, DASH, Simple Shoulder Test, ASES, SF-12). Electromyography (EMG) of the deltoid muscle was performed to determine axillary nerve damage. Ultrasound of both shoulders included CEUS and Power Doppler after deltoid muscle activation via active abduction for two minutes.

RESULTS

None of the examinations and scores showed significant differences between ORIF and MIPO patients, the psychosocial outcome was similar. The fracture types were equally distributed in both groups. The normalized Constant Score was 76.3±18.6 in the ORIF and 81.6±16.1 in the MIPO group (p=0.373). Deltoid muscle perfusion in CEUS and Power Doppler revealed no differences between both approaches. EMG excluded functionally relevant axillary nerve injuries. Compared with the contralateral shoulder, Constant- and ASES-Scores (p≤0.001 for both ORIF and MIPO) as well as the deltoid CEUS perfusion (ORIF p=0.035; MIPO p=0.030) were significantly worse for both approaches.

CONCLUSIONS

Convincing consensus of functional, ultrasonographic and neurologic examinations demonstrated comparable outcomes after deltopectoral and deltoid-splitting approach. The quantification of the deltoid muscle perfusion with CEUS indicates that the proclaimed benefits of the MIPO approach on soft tissue might not be as great as expected.

Minimally invasive plate osteosynthesis with a locking compression plate is superior to open reduction and internal fixation in the management of the proximal humerus fractures

BACKGROUND

The use of minimally invasive plate osteosynthesis (MIPO) via anterolateral deltoid splitting has good outcomes in the management of proximal humerus fractures. While using this approach has several advantages, including minimal soft tissue disruption, preservation of natural biology and minimal blood loss, there is an increased risk for axillary nerve damage. This study compared the advantages and clinical and radiological outcomes of MIPO or open reduction and internal fixation (ORIF) in patients with proximal humerus fractures.

METHODS

A matched-pair analysis was performed, and patient groups were matched according to age (±3 years), sex and fracture type. Forty-three pairs of patients (average age: MIPO, 63 and ORIF, 61) with a minimum follow-up of 12 months were enrolled in the study group. The patients were investigated radiographically and clinically using the Constant score.

RESULTS

The MIPO technique required less surgery time and caused less blood loss compared to ORIF (p < 0.01). In addition, MIPO required a smaller incision, resulted in less scarring, and was cosmetically more appealing and acceptable to female patients than ORIF. Following MIPO, patients had better functional results at 3 and 6 months, with better outcomes, less pain, higher satisfaction in activities of daily living, and a higher range of motion when compared to ORIF (p < 0.05). Fracture configuration, according to the AO/ASIF(Association for the Study of Internal Fixation) fracture classification, did not significantly influence the functional results. The complication rate was comparable between both groups.

CONCLUSION

The use of MIPO with a locking compression plate in the management of proximal humerus fractures is a safe and superior option compared to ORIF.

Gait and function as tools for the assessment of fracture repair - the role of movement analysis for the assessment of fracture healing

Assessment of gait and function might be as sensitive tool to monitor the progress of fracture healing. Currently available assessment tools for function use instrumented three dimensional gait analysis or pedobarography. The analysis is focused on gait or movement parameters and seeks to identify abnormalities or asymmetries between legs or arms. The additional inclusion of muscle function by electromyography can further elucidate functional performance and its temporal development. Alternative approaches abstain from directly assessing function in the laboratory but rather determine the amount of activities of daily living or the mere ability to perform defined tasks such as walking, stair climbing or running. Some of these methods have been applied to determine recovery after orthopaedic interventions including fracture repair. The combination of lab-based functional measurements and assessment of physical activities in daily live may offer a valuable level of information about the gait quality and quantity of individual patients which sheds light on functional limitations or rehabilitation of gait and mobility after a disease or injury and the respective conservative, medical or surgical treatment.

Prediction of the location of the anterior branch of the axillary nerve, using correlations with physical factors: a cadaveric study

BACKGROUND

Although axillary nerve injury is a catastrophic surgical complication, there is little data for precise prediction of the location of that nerve's anterior branch. To address that, the authors searched for a useful correlation between the acromion-axillary nerve distance (AAND) and one or more physical factors.

METHODS

The heights, humeral lengths, AAND, and axillary nerve indexes (ANI: ratio between AAND and humeral length) of 25 male and 20 female cadavers were determined. Any gender differences in the mean measurements were determined. The correlations of each AAND with height, humeral length, and ANI were determined. The authors determined that using the ANI and the humeral length allowed the shortest prediction of the AAND.

RESULTS

The mean AAND, cadaver height, and humeral length were 6.5 ± 0.8, 164.9 ± 10.0, and 33.5 ± 2.7 cm, respectively. An independent t test revealed significant gender differences in the mean AAND (P = .003), height (P = .000), and humeral length (P = .000), but not in the mean ANI (P = .564). The Pearson coefficients for the associations of the AAND with height (r = .767), humeral length (r = .797) and ANI (r = .732) demonstrated strong correlations (P < .001), especially with humeral length. The use of the ANI with the humeral length yielded the shortest predictions of AAND, with a 97.8% probability of safety.

CONCLUSION

There is a strong correlation between AAND and humeral length. In clinical practice, humeral length and ANI are useful for predicting the location of the anterior branch of the axillary nerve, when the arm is positioned at the side in neutral rotation.