Proximal humerus fractures are common orthopaedic injuries typically seen in the elderly1. They have an incidence of 141 per 100,000 persons in men and 383 per 100,000 in women per year. The most common mechanism is a low-energy fall from standing height. Hematoma typically accumulates at the fracture, which is critical in the healing process2. It promotes angiogenesis, osteogenesis, and chemotaxis of immunoregulators to the fracture3. Surgical management is a risk factor for infection, exposing the fracture site to potential contaminants, even in the sterile environment of an operating room (OR)4. Bacterial infection of a fracture hematoma following nonoperative management has only been reported following sternal fractures5-7. We present 2 cases of infection in patients with closed, proximal humerus fractures being treated nonoperatively.
The patients were informed that data concerning their cases would be submitted for publication, and they provided consent.
Case 1. A 57-year-old woman with a history of Crohn's disease (post colectomy), rheumatoid arthritis (on disease modifying agents), and splenectomy was found down at her home after an unknown period. She had a right, proximal humerus fracture from a low-energy fall 2 weeks ago, being managed conservatively (Fig. 1).
Fig. 1-A and Fig. 1-B Anteroposterior (Fig. 1-A) and lateral (Fig. 1-B) views of a right proximal humerus fracture showing significant anterior angulation and medialization of the distal fragment.
The patient was in septic shock with altered mental status, and on examination of the right shoulder, there was erythema and an area of fluctuance. Laboratory workup revealed a white blood cell count of 21.3 × 109//L with 85% neutrophils. The erythrocyte sedimentation rate was 95 mm/h, and the C-reactive protein (CRP) level was 328.58 mg/L. The fluid collection about the right shoulder fracture was aspirated in the emergency department with gross purulence positive for methicillin-sensitive Staphylococcus aureus (MSSA). A magnetic resonance image (MRI) with contrast showed an 8.6-cm area with peripherally enhanced, multilobulated fluid collection at the fracture site. (Fig. 2) The fracture was a 2-part surgical neck fracture with anterior displacement and angulation of the shaft component, injuring the anterior deltoid muscle.
She was urgently brought to the OR for irrigation and debridement of the right shoulder including the fracture site and glenohumeral joint. Intraoperative findings revealed accumulation of pus throughout the fracture site including the medullary canal of the humerus and subacromial space; the rotator cuff appeared intact. The abscess tracked superficially through the large tear in the anterior deltoid muscle created by the displaced shaft fragment. The patient was placed on broad-spectrum antibiotics and was sent to the medical intensive care unit.
The patient continued to show symptoms of ongoing infection, and another MRI was obtained, showing fluid collections extending down the biceps brachii into the forearm and along the rotator cuff to the medial scapula. The patient returned to the OR for a repeat irrigation and debridement. The subacromial space was opened, and a pulsatile irrigator was used to thoroughly irrigate. The long head of the biceps was edematous and infected; therefore, it was resected. Nonviable bone was removed, included approximately 1 cm of proximal humeral shaft.
Given the high likelihood of nonunion and the detrimental effect of the apex anterior displacement of the fracture on the soft tissues, the decision was made to stabilize the fracture. Using drill holes and #2 nylon sutures, a modified “parachute technique” was performed8. The humeral head was first impacted onto the distal fragment, maintaining the anatomic angular relationships of the proximal humerus. Multiple sutures were then placed through the drill holes distally and rotator cuff insertions proximally to hold the impacted reduction. A wound VAC was placed to promote soft tissue healing. Postoperatively, her septic shock and multiorgan system failure resolved.
The patient was switched to intravenous nafcillin on discharge from the hospital for a total 6-week course; then, antibiotics were discontinued. She was closely monitored by infectious disease and orthopaedic surgery and showed no signs of recurrent infection. The patient is 2 years post-surgery with evidence of healing at her proximal humerus fracture site (Fig. 3) and has regained almost full active range of motion (forward elevation to 120°, external rotation to 30°, and internal rotation to thoracolumbar junction) with intact rotator cuff strength, negative external rotation lag sign, and negative belly press test (Fig. 4).
Case 2. A 50-year-old woman with a history of alcoholic cirrhosis, hepatitis B, hemorrhagic stroke, and subsequent seizure disorder who sustained a right proximal humerus fracture after a syncopal fall (Fig. 5). Following a workup for the syncope and nonoperative management of her proximal humerus fracture, she was discharged home.
Fig. 5-A and Fig. 5-B Anteroposterior (Fig. 5-A) and lateral (Fig. 5-B) views of a right proximal humerus fracture showing significant anterior and lateralization of the distal fragment.
The patient presented to the hospital 2 weeks later with generalized fatigue, altered mental status, and failure to thrive. Infectious workup at that time revealed MSSA bacteremia and Methicillin-resistant Staphylococcus aureus (MRSA) urinary tract infection. Her examination was limited, given the fracture, but included pain with motion of the shoulder. An MRI without contrast of the shoulder revealed a large fluid collection suspicious for an abscess versus hematoma over the anterior aspect of the shoulder (Fig. 6). Given elevated inflammatory labs (CRP 73.8 mg/L), an ultrasound-guided aspiration of the fluid collection was performed, which yielded frank pus. Laboratory analysis of the fluid showed gram-positive cocci, and cultures revealed S. aureus.
An irrigation and debridement through a deltopectoral interval was performed where purulent fluid was encountered immediately upon incision of skin. A capsulotomy was performed, and the abscess did not appear to violate the joint; however, it was thoroughly irrigated. The rotator cuff appeared intact. A drain was placed into the abscess cavity to allow for drainage from the surgical site. The patient completed 6 weeks of intravenous vancomycin subsequently.
The patient has unfortunately been hospitalized multiple times over the past 2 years for medical issues (hypoglycemia, esophageal bleeding, and multiple episodes of hepatic encephalopathy). Her most recent radiographs at 2 years after surgery reveal a nonunion of her proximal humerus fracture (Fig. 7). Given her multiple medical comorbidities and the increased risk of reinfection, it was determined that the patient was not an operative candidate for fixation or arthroplasty. At her most recent follow-up visit 2 years after surgery, the patient was noted to attain 50° of active forward flexion and 10° of active abduction, with limited active external rotation to 15°. Her rotator cuff strength was intact, with no lag signs present. She uses the extremity for activities of daily living.
Although proximal humerus fractures are common, we believe that this is the first report of infection of these nonoperatively managed injuries. The mechanism by which these patients developed infection is likely hematologic seeding of the fracture hematoma. Both patients were immunocompromised, which may have played a critical role in the development of infection. With the rich collateral vascular network present in the shoulder, hematomas and significant bruising are often encountered after proximal humerus fractures. It is well documented that the vessels that supply the proximal humerus (posterior and anterior circumflex humeral) are often injured in the setting of fracture9. Two-part fractures with significant anterior displacement of the shaft can also tear through the deltoid, creating a large space for hematoma formation.
Hoff et al. have demonstrated that patients with autoimmune disorders, alcoholism, or osteoporosis exhibit an abnormal response to the fracture hematoma microenvironment10. In particular, they noted that in immunocompromised patients, inflammatory cells are unable to adapt to the relative hypoxic environment created by a fracture hematoma. In their study, there was diminished expression of the osteoblast differentiation transcription factor RUNX2 compared with healthy subjects, which may account for the prolonged union times seen in immunocompromised patients. Other inflammatory markers such as IL-8 and CXCR4 were elevated compared with healthy individuals, suggesting a disturbed inflammatory response. These variations in the inflammatory response warrant further investigation to determine the role they may play in infection following closed fractures10.
Another noteworthy aspect of case 1 was the decision to surgically stabilize the fracture at the time of the second surgery. The proximal and distal fragments were secured using a modified parachute technique using monofilament suture only. This reduced the motion at the fracture site allowing for union of the fracture and also decreased the pressure and damage to surrounding soft tissue8. Monofilament suture, such as #2 nylon, decreases the risk of biofilm formation compared with braided suture11. The risks and benefits of suture fixation need to be evaluated on a case-by-case basis; however, we believe that the risk of biofilm formation on the monofilament suture is small. If the patient did not clear the infection, humeral head resection with or without antibiotic spacer placement would be considered.
These 2 cases demonstrate the need for further investigation into the incidence of infected fracture hematomas in patients treated nonoperatively, particularly, proximal humerus fractures. With the increasing incidence of proximal humerus fractures secondary to the rapidly aging population of the United States, this topic may become more important. Physicians must pay attention to immunocompromised patients who present with proximal humerus fractures, especially displaced 2-part surgical neck fractures with anterior deltoid injury. These patients may develop a hematoma infection with potential rapid progression to septic shock.
1. Dimai HP, Svedbom A, Fahrleitner-Pammer A, Pieber T, Resch H, Zwettler E, Thaler H, Szivak M, Amrein K, Borgström F. Epidemiology of proximal humeral fractures in Austria between 1989 and 2008. Osteoporos Int. 2013;24:2413-21.
2. Kolar P, Schmidt-Bleek K, Schell H, Gaber T, Toben D, Schmidmaier G, Perka C, Buttgereit F, Duda GN. The early fracture hematoma and its potential role in fracture healing. Tissue Eng Part B Rev. 16(4):427-34.
3. Kolar P, Gaber T, Perka C, Duda GN, Buttgereit F. Human early fracture hematoma is characterized by inflammation and hypoxia. Clin Orthop Relat Res. 2011;469(11):3118-26.
4. Cheung EV, Sperling JW, Cofield RH. Infection associated with hematoma formation after shoulder arthroplasty. Clin Orthop Relat Res. 2008;466(6):1363-7.
5. Wehrens XHT, Doevendans PA, Van Dantzig JM, Snoep G, Wellens HJ. Infected sternal fracture hematoma after cardiopulmonary resuscitation initially seen as pericarditis. Am Heart J. 1996;132(3):685-6.
6. Young S, Beniyasi FJ, Munthali B, Banza L. Infection of the fracture hematoma from skeletal traction in an asymptomatic HIV-positive patient additional support for early surgical treatment of femoral fractures in people living with HIV in low-income countries? Acta Orthop. 2012;83:423-5.
7. Dupley L, Berg AJ, Mohil R. Secondary infection of haematoma following closed acromioclavicular joint dislocation. BMJ Case Rep. 2016;2016:bcr2015211090.
8. Banco SP, Andrisani D, Ramsey M, Frieman B, Fenlin JM. The parachute technique: valgus impaction osteotomy for two-part fractures of the surgical neck of the humerus. J Bone Joint Surg Am. 2001;83-A(suppl 2):38-42.
9. Meyer C, Alt V, Hassanin H, Heiss C, Stahl JP, Giebel G, Koebke J, Schnettler R. The arteries of the humeral head and their relevance in fracture treatment. Surg Radiol Anat. 2005;27:232-7.
10. Hoff P, Gaber T, Schmidt-Bleek K, Sentürk U, Tran CL, Blankenstein K, Lütkecosmann S, Bredahl J, Schüler HJ, Simon P, Wassilew G, Unterhauser F, Burmester GR, Schmidmaier G, Perka C, Duda GN, Buttgereit F. Immunologically restricted patients exhibit a pronounced inflammation and inadequate response to hypoxia in fracture hematomas. Immunol Res. 2011;51:116-22.
11. Morris MR, Bergum C, Jackson N, Markel DC. Decreased bacterial adherence, biofilm formation, and tissue reactivity of barbed monofilament suture in an in vivo contaminated wound model. J Arthroplasty. 2017;32:1272-9.
Supplemental Digital Content
Copyright © 2019 by The Journal of Bone and Joint Surgery, Incorporated