Katthagen, Arthroscopy 2016 - The Effects of Arthroscopic Lateral Acromioplasty on the Critical Shoulder Angle and the Anterolateral Deltoid Origin: An Anatomic Cadaveric Study - Article Summary

The Effects of Arthroscopic Lateral Acromioplasty on the Critical Shoulder Angle and the Anterolateral Deltoid Origin: An Anatomic Cadaveric Study

Katthagen, Millett, et al.·Arthroscopy·2016·112 citations·Biomechanical study

Purpose

To investigate if (1) an anterolateral acromioplasty and (2) a lateral acromion resection alter the critical shoulder angle (CSA) without affecting the deltoid origin.

Methods

First, the native CSAs of 10 human cadaveric shoulders (6 male and 4 female specimens; mean age, 54.2 years) were determined with the use of fluoroscopy.
Setup allowed for consistent repetitive measurements.
Next, a standard arthroscopic anterolateral acromioplasty was performed to create a type 1 acromion, and the CSA was reassessed fluoroscopically.
Afterward, a lateral acromioplasty was performed with a 5-mm lateral acromion resection using a 5-mm burr, and the CSA was measured again.
The native CSA was compared with (1) the CSA after acromioplasty and (2) the CSA after acromioplasty and lateral acromion resection using a paired t test.
Finally, the acromial deltoid attachment was evaluated anatomically for damage to the anterolateral origin.

Results

The mean native CSA (34.3 ± 2.1) was reduced significantly by acromioplasty (33.1 ± 2.0, P < .001) and further reduced by lateral acromion resection (31.5 ± 1.7, P < .001).
Anterolateral acromioplasty reduced the CSA by a mean of 1.4 (95% confidence interval boundaries, 0.8 and 1.9), and in combination with lateral acromion resection, the CSA was reduced by a mean of 2.8 (95% confidence interval boundaries, 2.1 and 3.5).
In all specimens (5 of 5) with a presurgery CSA of 35 or greater, the CSA was reduced to the range of 30 to 35 by the combination of both techniques.
However, in 2 specimens with a CSA of approximately 32, the CSA was reduced to less than 30.
The acromial deltoid attachment was found to be well preserved in all specimens.

Conclusions

Arthroscopic anterolateral acromioplasty and a 5-mm lateral acromion resection each reduced the CSA significantly and did not damage the deltoid origin.

Clinical Relevance: The combination of both techniques could potentially be used in clinical practice to reduce a CSA greater than 35 to the desired range of 30 to 35.

Supplemental

The Effects of Arthroscopic Lateral Acromioplasty on the Critical Shoulder Angle and the Anterolateral Deltoid Origin: An Anatomic Cadaveric Study

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The Effects of Arthroscopic Lateral Acromioplasty on the Critical Shoulder Angle and the Anterolateral Deltoid Origin: An Anatomic Cadaveric Study

Katthagen, Millett, et al.·Arthroscopy·2016·112 citations·Biomechanical study

DOI·PubMed

Purpose

To investigate if (1) an anterolateral acromioplasty and (2) a lateral acromion resection alter the critical shoulder angle (CSA) without affecting the deltoid origin.

Methods

First, the native CSAs of 10 human cadaveric shoulders (6 male and 4 female specimens; mean age, 54.2 years) were determined with the use of fluoroscopy.
Setup allowed for consistent repetitive measurements.
Next, a standard arthroscopic anterolateral acromioplasty was performed to create a type 1 acromion, and the CSA was reassessed fluoroscopically.
Afterward, a lateral acromioplasty was performed with a 5-mm lateral acromion resection using a 5-mm burr, and the CSA was measured again.
The native CSA was compared with (1) the CSA after acromioplasty and (2) the CSA after acromioplasty and lateral acromion resection using a paired t test.
Finally, the acromial deltoid attachment was evaluated anatomically for damage to the anterolateral origin.

Results

The mean native CSA (34.3 ± 2.1) was reduced significantly by acromioplasty (33.1 ± 2.0, P < .001) and further reduced by lateral acromion resection (31.5 ± 1.7, P < .001).
Anterolateral acromioplasty reduced the CSA by a mean of 1.4 (95% confidence interval boundaries, 0.8 and 1.9), and in combination with lateral acromion resection, the CSA was reduced by a mean of 2.8 (95% confidence interval boundaries, 2.1 and 3.5).
In all specimens (5 of 5) with a presurgery CSA of 35 or greater, the CSA was reduced to the range of 30 to 35 by the combination of both techniques.
However, in 2 specimens with a CSA of approximately 32, the CSA was reduced to less than 30.
The acromial deltoid attachment was found to be well preserved in all specimens.

Conclusions

Arthroscopic anterolateral acromioplasty and a 5-mm lateral acromion resection each reduced the CSA significantly and did not damage the deltoid origin.

Clinical Relevance: The combination of both techniques could potentially be used in clinical practice to reduce a CSA greater than 35 to the desired range of 30 to 35.

Purpose

To investigate if (1) an anterolateral acromioplasty and (2) a lateral acromion resection alter the critical shoulder angle (CSA) without affecting the deltoid origin.

Methods

First, the native CSAs of 10 human cadaveric shoulders (6 male and 4 female specimens; mean age, 54.2 years) were determined with the use of fluoroscopy.
Setup allowed for consistent repetitive measurements.
Next, a standard arthroscopic anterolateral acromioplasty was performed to create a type 1 acromion, and the CSA was reassessed fluoroscopically.
Afterward, a lateral acromioplasty was performed with a 5-mm lateral acromion resection using a 5-mm burr, and the CSA was measured again.
The native CSA was compared with (1) the CSA after acromioplasty and (2) the CSA after acromioplasty and lateral acromion resection using a paired t test.
Finally, the acromial deltoid attachment was evaluated anatomically for damage to the anterolateral origin.

Results

The mean native CSA (34.3 ± 2.1) was reduced significantly by acromioplasty (33.1 ± 2.0, P < .001) and further reduced by lateral acromion resection (31.5 ± 1.7, P < .001).
Anterolateral acromioplasty reduced the CSA by a mean of 1.4 (95% confidence interval boundaries, 0.8 and 1.9), and in combination with lateral acromion resection, the CSA was reduced by a mean of 2.8 (95% confidence interval boundaries, 2.1 and 3.5).
In all specimens (5 of 5) with a presurgery CSA of 35 or greater, the CSA was reduced to the range of 30 to 35 by the combination of both techniques.
However, in 2 specimens with a CSA of approximately 32, the CSA was reduced to less than 30.
The acromial deltoid attachment was found to be well preserved in all specimens.

Conclusions

Arthroscopic anterolateral acromioplasty and a 5-mm lateral acromion resection each reduced the CSA significantly and did not damage the deltoid origin.

Clinical Relevance: The combination of both techniques could potentially be used in clinical practice to reduce a CSA greater than 35 to the desired range of 30 to 35.

Purpose

To investigate if (1) an anterolateral acromioplasty and (2) a lateral acromion resection alter the critical shoulder angle (CSA) without affecting the deltoid origin.

Methods

First, the native CSAs of 10 human cadaveric shoulders (6 male and 4 female specimens; mean age, 54.2 years) were determined with the use of fluoroscopy.
Setup allowed for consistent repetitive measurements.
Next, a standard arthroscopic anterolateral acromioplasty was performed to create a type 1 acromion, and the CSA was reassessed fluoroscopically.
Afterward, a lateral acromioplasty was performed with a 5-mm lateral acromion resection using a 5-mm burr, and the CSA was measured again.
The native CSA was compared with (1) the CSA after acromioplasty and (2) the CSA after acromioplasty and lateral acromion resection using a paired t test.
Finally, the acromial deltoid attachment was evaluated anatomically for damage to the anterolateral origin.

Results

The mean native CSA (34.3 ± 2.1) was reduced significantly by acromioplasty (33.1 ± 2.0, P < .001) and further reduced by lateral acromion resection (31.5 ± 1.7, P < .001).
Anterolateral acromioplasty reduced the CSA by a mean of 1.4 (95% confidence interval boundaries, 0.8 and 1.9), and in combination with lateral acromion resection, the CSA was reduced by a mean of 2.8 (95% confidence interval boundaries, 2.1 and 3.5).
In all specimens (5 of 5) with a presurgery CSA of 35 or greater, the CSA was reduced to the range of 30 to 35 by the combination of both techniques.
However, in 2 specimens with a CSA of approximately 32, the CSA was reduced to less than 30.
The acromial deltoid attachment was found to be well preserved in all specimens.

Conclusions

Arthroscopic anterolateral acromioplasty and a 5-mm lateral acromion resection each reduced the CSA significantly and did not damage the deltoid origin.

Clinical Relevance: The combination of both techniques could potentially be used in clinical practice to reduce a CSA greater than 35 to the desired range of 30 to 35.