PROXIMAL HUMERAL FRACTURES

Abstract

Proximal humeral fractures account for approximately 4–5% of all fractures seen in the emergency departments. Of all shoulder injuries they account for aproximatelly 53%. In 1970 Neer published his classic study, in which he described a new method of classification, and gave recommendations for treatment. Neer recommended ORIF for three-part fractures, and prosthetic replacement for four-part fractures and fracture-dislocations. However there is still disagreement on the management of the displaced humeral fractures.

Diagnosis

Accurate radiographic evaluation, is essential in order to make a correct classification of the proximal humeral fractures. The radiographic examination consists of films from three different views. The anterio-posterior (AP), lateral (Y view of the scapula), and the axillary one. The AP view will assess the fracture position, and by centring it 30 degrees posteriorly and obliquely, clearly image the glenohumeral joint space. The lateral view is taken perpendicular to the scapular plain. The head overlaps the glenoid, and projects on the centre of a “Y“, formed by acromion, the coracoid superiorly, and the scapular body inferiorly. In this projection any large avulsed greater tuberosity fragments are usually easy to visualise posteriorly, and the lesser tuberosity is visualised medialy.

The axillary view is the most useful in assessing the relationship between the humeral head and the glenoid. Fracture dislocations, and true posterior dislocations can be easily distinguished in the axial view. Computer tomography, plain or with three dimensional reconstruction-views might also help the surgeon to make an accurate diagnosis and in preoperative planning.

Classification

A valid classification system can be useful as a tool to select the optimal treatment. The system should be comprehensive enough to reflect the complex fracture pattern, and specific enough to allow an accurate diagnosis. The classification should be useful as a tool for identifying those fractures which should be operated upon.

In 1935, Codman proposed a new classification system based on four different anatomical fragments of the proximal humerus. The anatomical head, the greater tuberosity, the lesser tuberosity and the humeral shaft. Codman stressed that the musculotendinous cuff attachment to each fragment was of major significance to the fracture pattern.

In 1970 Neer further developed Codmans classification, stressing the importance of the biomechanical forces, and the degree of displacement for more complex fractures. When any of the four major segments is displaced over 1 cm or angulated more than 45 degrees, the fracture is considered to be displaced: Group 1: all fractures regardless of the level or number of fracture lines, in wich NO segments are displaced. Group 2: a two-part fracture is one in which one fragment is displaced in reference to the other three fragments. Group 3: a three-part fracture is one in which two fragments are displaced in relationship to each other and the other two are undisplaced fragments, but the head remains in contact with the glenoid. Group 4: a four-part fracture is one in which all four fracture fragments are displaced; the articular surface of the head is out of contact with the glenoid and angulated either laterally, anteriorly, posteriorly, inferiorly, or superiorly. Furthermore it is detached from both tuberosities. Neer has also emphasised the term fracture dislocation. It exists when the head is displaced outside the joint space rather than subluxated or rotated and there is, in addition, a fracture. The degree of displacement is directly related to the clinical outcome and the choice of treatment.

In the 1970’s the AO group from Switzerland, emphasised the importance of the blood supply to the articular surface of the humeral head. Since the risk for avascular necrosis was high, they based their classification on the vascular anatomy of the proximal humerus. The system classified the fractures into three different categories:

Group A: Extra-articular, unifocal fracture.

Group B: Partially extra-articular, bi-focal fracture.

Group C: Articular fracture.

Each group is sub-divided into three categories, from less to more serious lesions. This gave us 27 different sub-groups to analyse and interpret. The AO system is easy to use for the diaphyseal segments of the femur, tibia and humeral shaft, but applying it to the proximal humerus is confusing, and makes it more difficult to use than the Neer system. Consequently the AO classification system has not gained general acceptance among shoulder surgeons.

The reliability and the reproducibility of these classifications have been questioned Unfortunately, we do not have a better classification system on hand and therefore the Neer system is still widely used.

Treatment

Many methods of treatment of proximal humeral fractures have been proposed during the past 50 years, creating a great deal of controversy and confusion. There are two main treatment options: Non-operative treatment and operative.

Conservative treatment

Approximately 80% of all proximal humeral fractures are non-displaced, or only minimally displaced, and the clinical outcome is satisfactory after conservative treatment. After some days of rest, early mobilisation with gentle physiotherapy is of great importance.

Operative treatment

Various types of osteosynthesis have been suggested. Semitubular straight or angulated plates, screws, Rush pins, external fixators, cerclage wires, tension band technique or K-wires with bone grafting have been used. The results reported range from excellent to poor. In cases of three- and four- part fractures, most authors have used open reduction with internal fixation. Because of poor bone quality, and a torn cuff, especially in elderly patients, osteosynthesis is not always the best choice. Hemiarthroplasty is reported to give an excellent outcome in many studies. In fracture dislocations, when closed reduction is not possible, the only way to restore the dislocated shoulder joint is to perform an open reduction and stabilise the fracture with an osteosynthesis implant, or replace the humeral head with a hemiarthroplasty.

Scoring systems for evaluation of the end results

There are two rating systems generally used. The Neer system from 1970 has been widely used in a number of studies, all over the world, and the Constant-Murley system from 1987 has been recommended for use in Europe. Neer’s rating system from 1970 is used to assess shoulder function, after fractures, arthroplasty and dislocations. It is based on a 100 units scale, with points for pain (35), function (30), range of motion (25), and anatomy (10). In 1987 Constant and Murley designed a European scoring system, claiming it to be applicable for measuring shoulder function regardless of diagnosis. This system is also based on a 100 point scale. The degree of pain, activities of daily living, strength, and active range of movement are assessed. The results are then related to gender, age and activity level of the patient.

Both systems has recently been questioned because of its low reliability. Confusion remains because different authors from the USA and Europe continue to use their own criteria for evaluation. Consequently, it is not unusual that the reported results after fracture treatment vary, depending on which rating system was used.