Summary
Proximal humeral fractures are the third most common fractures and affect both young and elderly patients. Neer’s classification system is commonly used in determining fracture patterns but has recently been found to have poor reliability and reproducibility. Protecting the posterior humeral circumflex artery during fracture fixation may minimize loss of the blood supply to the humeral head as the anterolateral ascending branch of the anterior circumflex artery supplies the humeral head to a lesser degree than originally believed. Clinically significant difference in patient-reported outcomes and function have not been observed between surgical and nonoperative treatment options for proximal humeral fractures. Open reduction and internal fixation with locked plating has better functional and patient-reported outcomes than hemiarthroplasty. In the past decade, reverse shoulder arthroplasty has become an attractive approach for managing proximal humeral fractures as the prosthesis can compensate for tuberosity complications. Overall, thorough consideration of bone quality, fracture patterns, and the myriad treatment options available is necessary to successfully manage proximal humeral fractures.
19 Proximal Humeral Fractures
I. Background
5% of all fractures, third most common fracture
Female to male ratio 2–4:1
Increasing incidence with aging population
Associated injuries:
Nerve: Axillary
Vascular: Axillary (5% of four-part fractures)
Other: Rib fracture, pneumothorx. 1
Bimodal age distribution:
High-energy injuries in younger patients
Osteoporotic fractures often associated with low-energy trauma in elderly patients.
Fracture patterns are dictated by bone structure and deforming muscle forces. 2
II. Neer classification of humeral head fractures
III. Valgus impacted fractures (▶Fig. 19.2)
Not included in Neer’s original classification
Accounts for 14 to 35% of four-part fractures
Preserved medial soft tissue hinge preserves blood supply to articular segment
Three-part fractures:
Most patients treated nonoperatively report good or excellent results. 5
Four-part fractures:
Open reduction and internal fixation (ORIF) and closed reduction percutaneous pinning (CRPP) provide satisfactory results in most patients. 6
IV. Vascularization of the humeral head
Quantifying arterial vascularization of the humeral head:
Anterolateral ascending branch of the anterior circumflex provides 36% of the blood supply to the humeral head
Posterior circumflex supplies posterior portion of greater tuberosity and a small posterior inferior part of the head:
Posterior humeral circumflex artery constitutes 64% of the blood supply to the humeral head.
Possible explanation for the relatively low rates of osteonecrosis
Protecting the posterior humeral circumflex artery during surgical approach may minimize loss of the blood supply to the humeral head. 7 , 8
Humeral head ischemia and necrosis predictors:
There is 97% positive predictive value of ischemia if following criteria are met:
Anatomic neck fracture
Short calcar (<8 mm displacement)
Disrupted medial hinge (>2 mm displacement). 9
Using above criteria:
Avascular Necrosis (AVN) group: 30% had all predictors
Non-AVN group: 4.7% had all predictors.
The three criteria are not sufficient in determining necrosis:
Recommend three-dimensional CT to better evaluate the calcar region. 10
V. Management of proximal humeral fractures
The severity of fracture comminution and displacement may have a more significant effect on functional outcomes than the choice of treatment. There is clear difference in prognosis between three- and four-part fractures, but not between two- and three-part fractures. 11 , 12
Nonoperative approach:
Entails use of sling or collar, cuff sling, and early physical therapy 13
Conservative treatment of proximal humeral fractures in older patients provides adequate pain relief:
However, it provides limited functional outcomes. 12
ORIF:
Most common, often used for younger patients, and results depend on bone quality and reduction
Minimally invasive lateral approach is the optimal treatment for Neer’s type 2 and type 3 proximal humeral fractures:
Allows for reliable fracture healing and little residual shoulder pain: 16
Mechanical failure of plates occur often due to malreduction.
Avoiding varus can decrease rate of postoperative failures: 17
Quantification of the deltoid muscle perfusion with dynamic contrast-enhanced ultrasound shows that benefits of the minimally invasive plate osteosynthesis approach on soft tissue might not be as beneficial as expected. 18
Medial support in locked plating (▶ Fig. 19.3 ):
Evidence that medial support was established:
i. Anatomic reduction of medial cortex
ii. Proximal fragment impacted laterally into the distal fragment
iii. Oblique locking screw was positioned inferomedially in the proximal head fragment.
Lack of medial support resulted in:
i. Increased loss of head height
ii. Increased risk of penetration of screws into the articular surface
iii. Increased loosening of screws. 19
Hemiarthroplasty:
Well-accepted procedure to treat four-part and three-part fractures associated with severe osteopenia, and head splitting and severe articular impression fractures
Satisfactory results in terms of range of motion, and pain relief can be expected in most patients. 20
Closed reduction external fixation (CREF):
External fixation achieves safe healing and effective management for displaced proximal humeral fractures 21
Percutaneous insertion of Kirschner wires from the upper lateral part of the humeral head through the medullary canal minimizes complications. 22
Total shoulder arthroplasty (TSA):
Reduces shoulder pain effectively for acute three- and four-part proximal humeral fractures
Late TSA is a satisfactory reconstructive option when primary treatment of proximal humeral fractures fail. 23
Reverse total shoulder arthroplasty (rTSA):
Attractive approach as the prosthesis can compensate for tuberosity complications 24
Using a dedicated stem is a viable solution to treat complex humeral fractures as reliable restoration of elevation can be expected 25
Quicker recovery but there are limited reconstructive options if complications occur
Use of rTSA has increased for treatment of three- and four-part proximal humeral fractures in the elderly
Lack of long-term studies with rTSA, so should be used conservatively for patients with high functional demands. 26 – 28