A stress fracture of the base of the acromion: a case report

Nonunion of the so-called acromion: a systematic review with consideration of the terminology

INTRODUCTION

There is no widely accepted standard for the classification and treatment of traumatic acromion/scapular spine fracture nonunion due to the scarcity of this condition and the confusion of terminology.

MATERIALS AND METHODS

PubMed and Scopus were searched using "scapular fracture" and "acromion fracture" or "scapular spine fracture" as search terms. The inclusion criteria were English full-text articles concerning acromion/scapular spine fracture nonunion that described patient characteristics and presented appropriate images. The exclusion criteria were cases without appropriate images. Citation tracking was conducted to find additional articles and notable full-text articles written in other languages. Fractures were classified using our newly proposed classification system.

RESULTS

Twenty-nine patients (19 men, 10 women) with 29 nonunions were identified. There were four type I, 15 type II, and 10 type III fracture nonunions. Only 11 fractures were isolated. The mean period from initial injury to final diagnosis was 35.2 ± 73.2 months (range 3-360 months) (n = 25). The most frequent cause of delayed diagnosis was conservative treatment for fracture in 11 patients, followed by oversight by the physician in 8. The most common reason for seeking medical advice was shoulder pain. Six patients received conservative therapy, and 23 received operative treatment. Fixation materials included various plates in 15 patients, and tension band wiring in 5. Bone grafting was performed in 16 patients (73%, 16/22). Of the 19 surgically treated patients with adequate follow-up, the outcome was rated excellent in 79%.

CONCLUSIONS

Isolated acromion/scapular spine fracture nonunion is rare. Fracture type II and III, arising in the anatomical scapular spine, accounted for 86% of the fractures. Computed tomography is required to prevent fracture oversight. Surgical therapy produces good stable results. However, it is important to select the appropriate surgical fixation method and material after considering the anatomical characteristics of the fracture and stress on the fractured portion.

LEVEL OF EVIDENCE

V.

Scapular Stress Fracture of the Inferior Angle in an Adolescent Swimmer

We present the case of a competitive swimmer who was 14 years, 9 months old and had a 4-month history of posterior shoulder pain. She was initially evaluated by her school's trainer and completed a 2-week rehabilitation program, but pain returned with return to swimming. After feeling a "pop" while swimming with an increase in associated shoulder pain, the patient presented for medical evaluation. Plain radiographs were read as unremarkable. A formal physical therapy program resulted in increased pain, and the patient returned to clinic within 2 weeks with pain out of proportion to examination. Magnetic resonance imaging at this time identified a stress fracture along the inferior angle of the scapula, prompting a complete shutdown of activity for 4 weeks with vitamin D and calcium supplementation. A physical therapy regimen was restarted at 6 weeks with complete resolution of symptoms and return to swimming at 3 months. This case report is important because it highlights a sports-related stress fracture of the inferior angle of the scapula, a finding not currently present in the literature, in a swimmer, a sport not yet associated with scapular stress fractures. [Orthopedics. 202x(xx):xx-xx.].

Causes of acromion and scapular spine fractures following reverse shoulder arthroplasty: a retrospective analysis and literature review

Purpose

Fractures of the acromion and the scapular spine are serious complications after reverse total shoulder arthroplasty. They concern about 4 to 5% of the patients and always result in a significant deterioration of shoulder function. Different causes have been taken into consideration, particularly stress or fatigue fractures. The purpose of the present study was to analyse our own cases and to discuss the causes reported in the literature.

Methods

We reviewed our shoulder arthroplasty registry and the consultation reports of the last ten years. The charts and radiographs of all patients who had a post-operative fracture of the acromion or the scapular spine were carefully examined and the results were compared with those of an age- and gender-matched control group.

Results

Twelve patients with an average age of 79 years sustained a fracture of the acromion (n = 6) or the scapular spine (n = 6). The time interval between the operation and the fracture averaged 26 months and ranged from three weeks to 70 months. Eight patients (67%) had a trauma. Seven of them reported a fall on the corresponding shoulder and one a heavy blow on the acromion. The four non-traumatic fractures were attributed to poor bone quality. All 12 patients had immediate pain and difficulty to actively elevate the affected arm. The time interval between the fracture and its diagnosis averaged ten weeks (0 to 10 months). At final follow-up, all patients could reach their face and refused further surgery. Two patients rated their result as good, six as acceptable and four as poor.

Conclusions

Our study cannot support the hypothesis that most acromion and scapular spine fractures after RSA are the result of increased tension in the deltoid or stress fractures. In our series, the majority of the fractures were related to a fall. Implantation of a reverse prosthesis exposes the acromion and makes it more vulnerable to direct trauma. Non-traumatic fractures were associated with poor bone quality.

Bilateral acromial stress fractures in a patient with a massive rotator cuff tear

Stress fractures of the acromion and scapular spine are well-known complications following reverse total shoulder arthroplasty. However, these fractures in patients with massive rotator cuff tear or cuff tear arthropathy are extremely rare, and the pathogenesis, clinical features, diagnosis, and treatment of these fractures are poorly understood. We report a case of bilateral stress fracture of the posterior angle of the acromion in a patient with massive rotator cuff tear and discuss the pathogenesis, clinical manifestation, and treatment with a review of the literature.

Does ORIF of rare scapular spine fractures sustained after reverse shoulder arthroplasty benefit elderly patients? A case-series appraisal

PURPOSE

Scapular spine fractures sustained after reverse shoulder arthroplasty (RSA) are debilitating for elderly patients with osteoporosis. We examined the 1-year postoperative outcomes of open reduction and internal fixation (ORIF) in a small case-series, and hypothesised that patients undergoing surgical treatment for post-RSA scapular spine fractures would improve in function and pain.

METHODS

Five consecutive RSA patients within our shoulder arthroplasty register who sustained a scapular spine fracture underwent ORIF using a double plating technique. Standard radiographs and clinical/patient-rated assessments of Constant-Murley (CS), Shoulder Pain And Disability Index (SPADI), Subjective Shoulder Value (SSV) and visual analogue scale (VAS) pain were made up to 12months post-ORIF. Patients were also asked to rate their satisfaction since the surgery. Post-ORIF complications were documented. All post-RSA data were used as a baseline measure for comparison with post-fracture outcomes.

RESULTS

Mean CS, SPADI and SSV scores as well as pain were similar to pre-fracture scores. All patients improved in function and pain, and would undergo the same procedure again. Individual cases of iatrogenic pneumothorax and screw loosening were reported.

CONCLUSIONS

ORIF is a viable option with adequate improvements in function and pain for elderly patients with debilitating scapular spine fractures after RSA.

The traumatic acromion fracture: review of the literature, clinical examples and proposal of a treatment algorithm

PURPOSE

Traumatic acromion fractures are rare and typically occur in patients with multiple fractures, which often delays diagnosis. Limited guidance exists on the treatment of these fractures. We present a review of the literature from the last 20 years and describe our experience in treating five patients-two conservatively and three with open reduction and internal fixations (ORIF).

METHODS

We used the U.S. National Library of Science database, MEDLINE^®, to search for all pertinent publications from January 1999 to December 2017. Included were retrospective or prospective studies, including case series and case reports, describing treatment for traumatic acromion fractures and clinical and/or radiological outcomes. For our case reports, we present five patients with traumatic acromion fractures who were treated at our institution between 2013 and 2017.

RESULTS

Through our review of 14 publications, we found that current recommendations are often based on a limited number of cases. No gold standard to treat these fractures exists. Most authors recommend anatomic reconstruction, especially for dislocated fractures, persistent symptomatic non-unions or additional injuries to the superior shoulder suspensory complex. There is no clear trend in terms of the operative technique. With regard to our five clinical examples that were all initially treated conservatively, two were successful and three eventually required reconstruction with ORIF. Based on the findings of this review, we proposed a treatment algorithm for traumatic acromion fractures.

CONCLUSIONS

A classification system providing clear guidance on treatment options is needed. Although the non-union rate with conservative treatment is relatively high, it is not always painful or limiting to shoulder function, especially in elderly or less active patients. Fixation seems to be a more suitable treatment option for active patients who are more likely to require revision of symptomatic non-unions.

Symptomatic pseudoarthrosis secondary to a stress fracture of the acromion

Fractures of the acromion are uncommon clinical entities, and stress fractures are even more rare, with few cases reported. Due to their rarity, stress fractures are often misdiagnosed. Here, we report a case of an elderly patient with an acromion stress fracture, which was overlooked, resulting in nonunion followed by the displacement of the distal portion of the acromion. The purpose of this report was to discuss this rare fracture, highlighting the importance of an accurate evaluation of radiological imaging as well as clinical data. (www.actabiomedica.it).

Osteosynthesis of type III acromial fractures with locking compression plate, lateral clavicular plate, and reconstruction plate: a biomechanical analysis of load to failure and strain distribution

BACKGROUND

Acromial stress fractures following reverse shoulder arthroplasty have been increasingly studied because of potential functional impairment caused by this complication. The purpose of this study was to evaluate and compare different plating techniques for a type III acromial fracture (also referred to as "scapular spine fracture") in a biomechanical setting with special regard to primary stability and modes of failure.

METHODS

Type III acromial fractures were simulated on 19 Sawbones scapulae and plated with either a lateral clavicular plate (LatCP), a locking compression plate (LCP), or a reconstruction plate (RecoP). We performed testing on 5 scapulae for each plate according to a staircase protocol (100 cycles each step): 50 N and 100 N, then increasing 100 N each step up to 800 N or until failure. The last series of mechanical tests included 3-dimensional micro-motion analysis.

RESULTS

The average force needed to cause failure of the osteosynthesis construct was 376 N for the LatCP, 506 N for the LCP, and 360 N for the RecoP. The difference between the LCP and RecoP was significant (P = .047). The average displacements of the acromion were 12.1 mm, 13.4 mm, and 11.7 mm, respectively. The spring constant was not significantly different between the plates. The LatCP showed increased strain medially, whereas the strain on the RecoP was spread more laterally. The LCP presented a balanced strain distribution, spread evenly over the fracture line.

CONCLUSIONS

In a biomechanical setting, the LCP showed superiority over the LatCP and RecoP as stabilization hardware for type III acromial fractures.