Biomechanical evaluation of internal fixation techniques for unstable meso-type os acromiale

Authors:

Ulrich J A Spiegl, Sean D Smith, Jocelyn N Todd, Coen A Wijdicks, Peter J Millett

Abstract:

Fusion of the acromial apophysis across the 4 distinct ossification centers typically occurs between the ages of 15 and 18 years. Os acromiale is described as a failure of osseous union between 2 of the apophyses, most commonly between the meso-acromion and meta-acromion. The frequency ranges from 1% to 15%. Commonly, os acromiale is a nonsymptomatic condition that is identified incidentally during radiographic examination of the shoulder. However, several clinical studies have reported symptomatic cases of os acromiale, with symptoms such as pain at the site of nonunion, decreased range of motion, pain during abduction, weakness, and pain during hypermobility. In addition, rotator cuff tears and impingement have been associated with this pathologic process.

In cases of failed conservative treatment of symptomatic os acromiale, a surgical approach is recommended, including fragment excision or surgical repair consisting typically of resection of the pseudarthrosis, reduction, and internal fixation. Fragment excision can be performed arthroscopically or through an open approach, although excision of larger types can result in deltoid impairment. Poor results have frequently been reported after open excision. Pagnani reported promising results after arthroscopic fragment resection in a young and athletic population with os acromiale at the junction between meso-type and meta-type. Larger fragments need to be preserved to prevent deltoid weakness, particularly in active individuals. Internal fixation has been the method of choice, although fixation techniques vary between studies, from fixation with tension wiring to cannulated screws inserted from anterior-posterior (A-P) or posterior- anterior. The biomechanical characteristics of different internal fixation modalities have not been compared.

Therefore, the purpose of this study was to compare the strength and stiffness of different internal fixation techniques at time zero for the operative treatment of unstable and symptomatic meso-type os acromiale in a cadaveric biomechanical model. The investigated techniques were cannulated screw fixation vs. cannulated screw fixation augmented with a tension band. The tension band technique was hypothesized to provide higher repair strength compared with isolated cannulated screw fixation.

For the complete study: Biomechanical evaluation of internal fixation techniques for unstable meso-type os acromiale

Peter Millett, MD

Average rating:

39 reviews

Alexandra Thompson

Mar 23, 2024

by Alexandra Thompson on Peter Millett, MD

110%

Dr. Millett and his team did a SLAP tear repair and bicep tenodesis on my left shoulder. I use my arms as an artist, and love to swim in the ocean, surf, paddle, and telemark ski. So regaining full use of my shoulder and keeping my bicep attached was very important to me. Now, over two years later, my shoulder has the equivalent range of motion as my other arm and as before the injury, and no pain. After the first three months it felt so good and was so strong that - to my horror - I completely forgot my six-month follow-up.

Not only did Dr. Millett and his team make my arm as good as new, but having had the experience of such kindness and expertise throughout the process of surgery and recovery is like an added shoulder superpower.

Thank you Rita, Brooke, Jason, Sarah, Camille, Olivia, Dr. Millett and everyone! And see you soon when my husband comes in for his knee...

Jeff Chandler

Jan 31, 2022

by Jeff Chandler on Peter Millett, MD

Flawless procedure, Easy recovery

Dr. Millet's repaired my knee and tibia, following a botched operation by a different surgeon. That procedure was virtually pain free and I was weight bearing within a few days. That was 18 years ago and the knee is still strong. A few years after the knee incident, Dr Millet repaired my shoulder. My insurance company approved me for 3 months of disability following that surgery. I was off pain medication in 2 days and had 90% range of motion within a week. I withdrew my disability claim and returned to work within two weeks of surgery. I’m not a famous athlete—just a regular guy. Nonetheless, I was treated like an NFL at the Steadman clinic. Most notable was the time for recovery. Other surgeons perform their hour-long task in the OR and don’t involve themselves in the other functions. Peter and his team manages the entire process from diagnosis, anesthesia, nursing care, and therapy. He takes a holistic approach to patient care and doesn’t skip any steps.

Jenn West

Jul 2, 2021

by Jenn West on Peter Millett, MD

Saved My Life

I went to Dr. Millett after 7 knee surgeries (6 on my right and 1 on my left) and had seen 11 different surgeons who all refused to remove femur metal from my right leg. I am highly allergic to metal and the chronic pain was leaving me bedridden for 3.5wks out of a month. He personally wrote me back on my inquiry, listened to my concerns, scheduled my surgery within a week (due to insurance issues) and personally followed up with my recovery. The level of patient care from Dr. Millett and his ENTIRE team is above any care I have ever received in my 20 years of dealing with orthopedic surgeons. There are not enough words to describe the level of care, dedication and professionalism you receive from Dr. Millett and his staff.
My only disappointment is that I did not find him sooner!!!

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