19 Proximal Humeral Fractures



Diana Zhu and Uma Srikumaran


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




  1. 5% of all fractures, third most common fracture



  2. Female to male ratio 2–4:1



  3. Increasing incidence with aging population



  4. Associated injuries:




    1. Nerve: Axillary



    2. Vascular: Axillary (5% of four-part fractures)



    3. Other: Rib fracture, pneumothorx. 1



  5. Bimodal age distribution:




    1. High-energy injuries in younger patients



    2. Osteoporotic fractures often associated with low-energy trauma in elderly patients.



  6. Fracture patterns are dictated by bone structure and deforming muscle forces. 2



II. Neer classification of humeral head fractures




  1. Fracture defined by number of parts



  2. Four parts (▶ Fig. 19.1 ):




    1. Humeral head (HH)



    2. Greater tuberosity (GT)

      Fig. 19.1 Neer classification for proximal humeral fractures.


    3. Lesser tuberosity (LT)



    4. Humeral shaft (HS).



  3. Definition of fracture parts:




    1. Displacement >1cm, or



    2. 45-degree angulation. 3



  4. Classification using the Neer system assigned on basis of computed tomography (CT) scans and radiographs are not very reliable or reproducible. 4



III. Valgus impacted fractures (▶Fig. 19.2)




  1. Not included in Neer’s original classification



  2. Accounts for 14 to 35% of four-part fractures



  3. Preserved medial soft tissue hinge preserves blood supply to articular segment

    Fig. 19.2 (a, b) Valgus impacted fracture.


  4. Three-part fractures:




    1. Most patients treated nonoperatively report good or excellent results. 5



  5. Four-part fractures:




    1. 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




  1. Quantifying arterial vascularization of the humeral head:




    1. Anterolateral ascending branch of the anterior circumflex provides 36% of the blood supply to the humeral head



    2. Posterior circumflex supplies posterior portion of greater tuberosity and a small posterior inferior part of the head:




      1. Posterior humeral circumflex artery constitutes 64% of the blood supply to the humeral head.



    3. Possible explanation for the relatively low rates of osteonecrosis



    4. Protecting the posterior humeral circumflex artery during surgical approach may minimize loss of the blood supply to the humeral head. 7 , 8



  2. Humeral head ischemia and necrosis predictors:




    1. There is 97% positive predictive value of ischemia if following criteria are met:




      1. Anatomic neck fracture



      2. Short calcar (<8 mm displacement)



      3. Disrupted medial hinge (>2 mm displacement). 9



    2. Using above criteria:




      1. Avascular Necrosis (AVN) group: 30% had all predictors



      2. Non-AVN group: 4.7% had all predictors.



    3. The three criteria are not sufficient in determining necrosis:




      1. 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




  1. Nonoperative approach:




    1. Entails use of sling or collar, cuff sling, and early physical therapy 13



    2. Conservative treatment of proximal humeral fractures in older patients provides adequate pain relief:




      1. However, it provides limited functional outcomes. 12



  2. ORIF:




    1. Most common, often used for younger patients, and results depend on bone quality and reduction



    2. Minimally invasive lateral approach is the optimal treatment for Neer’s type 2 and type 3 proximal humeral fractures:




      1. Nailing provides less stability for more than two fragmented fractures. 14 , 15



    3. Allows for reliable fracture healing and little residual shoulder pain: 16




      1. Mechanical failure of plates occur often due to malreduction.



    4. Avoiding varus can decrease rate of postoperative failures: 17




      1. 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



    5. Medial support in locked plating (▶ Fig. 19.3 ):




      1. 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.



      2. 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



  3. Hemiarthroplasty:




    1. Well-accepted procedure to treat four-part and three-part fractures associated with severe osteopenia, and head splitting and severe articular impression fractures

      Fig. 19.3 (a, b) Medial support in open reduction and internal fixation (ORIF).


    2. Satisfactory results in terms of range of motion, and pain relief can be expected in most patients. 20



  4. Closed reduction external fixation (CREF):




    1. External fixation achieves safe healing and effective management for displaced proximal humeral fractures 21



    2. Percutaneous insertion of Kirschner wires from the upper lateral part of the humeral head through the medullary canal minimizes complications. 22



  5. Total shoulder arthroplasty (TSA):




    1. Reduces shoulder pain effectively for acute three- and four-part proximal humeral fractures



    2. Late TSA is a satisfactory reconstructive option when primary treatment of proximal humeral fractures fail. 23



  6. Reverse total shoulder arthroplasty (rTSA):




    1. Attractive approach as the prosthesis can compensate for tuberosity complications 24



    2. Using a dedicated stem is a viable solution to treat complex humeral fractures as reliable restoration of elevation can be expected 25



    3. Quicker recovery but there are limited reconstructive options if complications occur



    4. Use of rTSA has increased for treatment of three- and four-part proximal humeral fractures in the elderly



    5. Lack of long-term studies with rTSA, so should be used conservatively for patients with high functional demands. 26 28

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Feb 6, 2021 | Posted by in ORTHOPEDIC | Comments Off on 19 Proximal Humeral Fractures
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