ANATOMY
The shoulder joint (glenohumeral joint) is a diarthrosis consisting of the head of the humerus and the glenoid cavity, part of the scapula. It is a spherical type of joint with high mobility and reduced stability.
DESCRIPTION – WHAT IS THE PROXIMAL HUMERUS FRACTURE?
When the word “proximal” is used to describe a part of the human body, it means that it is closer to the center of the body. In contrast, the outer part of the bone is described as “distal”.
In the case of the humerus, the proximal part corresponds to the “head” and therefore the fractures are also classified as fractures of the humeral head.
A fracture is defined as the discontinuation of a bone’s structure, that is, a “break”, and is usually the result of a fall or more serious injury. The fracture of the proximal end of the humerus concerns that part of the bone next to the glenoid cavity.
Reason – How do the fractures of the proximal humerus end occur?
The fractures of the proximal end of the humerus are in most cases the result of a fall or severe injury, such as car accidents. In elderly patients, where bones are osteoporotic, less force is required (low force injuries).
Young patients generally have stronger bones that cannot be fractured with a simple fall. A bone requires a greater amount of energy to be fractured, such as in a car accident or after falling from height, etc.
RADIOLOGICAL EXAMINATION
Radiological examination is usually sufficient to describe and confirm the diagnosis of a humeral fracture. In the emergency department, specific “trauma” shots (anteroposterior, transthoracic and axillary) are used to visualize the fracture in detail.
Computed tomography (CT) is not necessary for diagnosis, but is able to accurately and in detail describe a more complex fracture that may need further treatment (preoperative planning for surgery).
Magnetic resonance imaging (MRI) is able to visualize in detail – beyond the fracture – the soft tissue structures. However, it is not a screening test for fractures of the proximal end of the humerus.
CLASSIFICATION – Are there different types of fractures?
Fractures of the proximal or upper end of the humerus generally depend on the quality of the bone, the number of fractured “pieces” and the size of the comminution. A comminuted fracture refers to multiple fracture segments that can result from injury.
The concept of fractured segments, described and illustrated below, is an important factor in deciding the proper treatment of a fracture, whether it is conservative or surgical. According to the Neer classification, which is still in force, there are – potentially – four parts at the proximal end of the humerus; the head, the major and minor humeral tubercles and the diaphysis. The major and minor tubercles are sites of insertion of the rotator cuff tendons. In order to characterize a piece displaced in relation to others, it must create an angle greater than 45° and a displacement greater than 1 cm. This provides multiple combinations of fractures that are treated differently, as appropriate.
ADDITIONAL INFORMATION CONCERNING THE FRACTURE OF THE PROXIMAL END OF THE HUMERUS
Bone quality is an important factor in choosing the right treatment for a fracture. Elderly patients, due to osteoporosis, lose some of their bone mass and their bones become thinner, slimmer and therefore weaker.
Another important factor is the blood flow of the head of the humerus and its maintenance after injury. The risk of interruption of the blood flow increases as fractures become more complex and displaced and can lead to aseptic necrosis of the humeral head or osteonecrosis. In this case, which may take years, deformity, sedimentation and severe arthritis may occur with consequent pain and reduced functionality.
TREATMENT
MAINTENANCE TREATMENT – WHEN IS IT RECOMMENDED?
When the fracture is minimally displaced or when surgery may cause more problems (poor bone quality and concomitant pathological problems), conservative treatment is chosen.
Some patients may not be able to get surgery due to serious health problems or a lack of co-operation and compliance. In addition, the poor quality of bone may lead to failure of osteosynthesis. Therefore, in the case of slightly displaced fractures, conservative treatment can result into very good operating results.
In this case, the injured limb is placed on a shoulder immobilization system for 2 to 4 weeks (e.g. suspension folder), followed by a physiotherapy program that includes gentle stretching of the shoulder to restore movement. After the first month and, as appropriate, shoulder strengthening exercises are added.
SURGICAL TREATMENT – WHEN IS IT RECOMMENDED?
When fracture displacement constitutes fracture healing impossible then surgical treatment is recommended. If the bone quality is good then the most reasonable treatment option is internal osteosynthesis (ORIF). In some cases, fracture fragments can be reconstituted and stabilized with the help of radiologically fixated needles, but most often require open resection and internal osteosynthesis with a special anatomical plate and screws.
Semi-arthroplasty or subtotal arthroplasty: Many times, the fracture presents such a degree of dislocation or commination that osteosynthesis becomes impossible. If the parameters of the risk of aseptic necrosis of the head and increased age of the patient are also considered, then replacement of the head of the humerus (hemiarthroplasty) is the most appropriate treatment option. A basic prerequisite for surgery is to find and prepare the humeral tubercles on which the rotator cuff tendons are inserted and to fix them with strong sutures on the prosthesis.
REVERSE TOTAL SHOULDER ARTHROPLASTY FOR THE TREATMENT OF PROXIMAL HUMERUS FRACTURES: In elderly patients with poor bone quality (osteoporosis) and excessive comminution, semi-arthroplasty does not provided adequate results in functionality, as the humeral tubercles fixated in the prosthesis do not heal easily. In these cases, reverse total shoulder arthroplasty allows for better functional recovery of the shoulder.
Studies, to date, show that reversed total arthroplasty is a reasonable choice for comminuted and dislocated fractures in elderly patients, improving post-operative mobility (mainly limb lifting), regardless of the humeral tubercles’ healing.
