Page 38 - Delaware Medical Journal - September/October 2018

The Concept of Shoulder Protrusio
in the Setting of Osteogenesis Imperfecta
By Jeanne M. Franzone, MD; Kenneth J. Rogers, PhD, ATC; Michael B. Bober, MD, PhD and Richard W. Kruse, DO, MBA
Acetabular protrusio has been described in the setting of osteogenesis imperfecta (OI). The femoral head becomes enveloped in a deepened acetabular socket with protrusion into the pelvis. We report a similar finding in the shoulder such that the humeral head becomes enveloped within the overlying acromion process, with an associated deformity in the
distal third of the clavicle. The deformity has implications for the surgical treatment of humeral deformity in OI patients. Further investigation of the clinical ramifications is warranted, including the limitations on range of motion of the shoulder in patients who are often wheelchair users and potential effects on the rotator cuff and overall health-related quality of life and independent functioning.
INTRODUCTION
OI is a brittle-bone disease characterized by bone fragility, bone deformity, and frequent fractures, among a number
of other non-skeletal manifestations.1,2 Acetabular protrusio has long been described as a radiographic feature of patients with OI3 and has more recently been further delineated to be more common in those with severe Type III OI.4,5 It has been associated with coxa vara and increased risk of femoral neck fracture.5 Despite these advances in the understanding of acetabular protrusio in OI patients, preventative measures and possible treatment options have been lacking.
The hip joint and the shoulder joint share similarities in the sense of a rounded femoral or humeral head being encased within a socket of bone. The similarities in functional demand are greater in those with severe OI, given the preponderance of upper-extremity- weightbearing wheelchair users among the population of patients with severe OI. The impact of acromial protrusion in the general population has been found to have a relationship to degenerative rotator cuff disease6,7 and the shoulder
is known to be the most common site
of upper-extremity pain in paraplegic manual wheelchair users, occurring in up to two thirds of such patients;8 yet little has been described regarding the anatomy of the shoulder in patients with OI who develop acromial protrusio frequently in the setting of manual wheelchair use. We seek to introduce the concept of shoulder protrusio in a subset of patients with severe OI in order to set the groundwork for further investigation of the clinical and functional impact of deformity of this important, often weightbearing joint.
METHODS
Following approval from our Institutional Review Board, a review of selected charts shoulder deformity has been performed. The patients’ charts were reviewed for demographic and clinical information, including clinical severity of the OI
as well as ambulatory status. Patients using a wheelchair as a primary mode of transportation are considered upper- extremity-weightbearing patients.
CASE VIGNETTES
VIGNETTE 1. A 15-year-old boy with
severe OI and a manual wheelchair user presented with chronic left shoulder
pain. The pain was activity-related and
was worse with overhead activities. The left shoulder radiograph (Figure 1A) demonstrated a curved acromion reaching across and around the humeral head. A
CT scan (Figure 1B) helped demonstrate the humeral rod to not be the primary site of impingement. The patient’s symptoms persisted despite a subacromial injection of steroid and local anesthetic, and at the age of 18 years, he underwent an acromioplasty and removal of the left humeral rod, with ability to continue manual wheelchair use (Figure 1C).
VIGNETTE 2. Figure 2A demonstrates an anteroposterior view of the left shoulder of a 17-year-old boy with severe OI who is both a manual and power wheelchair user, indicated for left humerus realignment and intramedullary rodding. The distal third of the clavicle has a downward hook, and both the clavicle and acromion process have fully enveloped the
humeral head. Figure 2B demonstrates skin markings corresponding to the clavicle, acromioclavicular joint and the acromion. Figure 2C shows the left hip of the same young man, highlighting the parallel features of hip protusio and
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Del Med J | September/October 2018 | Vol. 90 | No. 7
Abstract