The conservative treatment for around 80% of the fractures is possible in the case of the proximal humerus. The management of these fractures is not possible by surgical methods. Certain difficulties can be encountered with this;
- Fracture reduction
- Increased risk of avascular necrosis
- Prolonged rehabilitation with the shoulder stiffness and pain
- Fracture stabilization
MIPO is possible with modern-day Implants like LCP (Large Fragment LCP Locking Compression Plate) and indirect reduction can result in addressing a few of the concerns. Although it is not possible to manage all humeral fractures with this minimally invasive technique it can result in leading and improvised outcomes.
For the classification of the proximal humeral, the use of Muller classification is done. The designation of the proximal humerus is by the 11 number.
- Type A fractures are extra-articular unifocal,
- Type B fractures are extra-articular bifocal and
- Type C fractures are articular fractures
Indications and contraindications for MIPO
The proper selectiveness is required while applying the MIPO technique for the proximal humerus fractures.
Surgical neck fractures with the greater tuberosity avulsion, surgical neck fractures with the extended shaft and valgus impacted fractures tend to be the good indications because of the good connection with the rotatory and cuff along with the soft tissue and periosteal attachment in the segments of fractures which remains attached to the fracture. With the use of the principle of ligamentotaxis, indirect fracture reduction can be placed along with the preservation of biology and blood supply.
Along the deep surface of deltoid muscles the axillary nerve runs around 6 cm from the acromion and the risk of the Trans deltoid with the lateral approach is also used as the entry portal for bone plate introduction in the craniocaudal direction. To avoid any kind of injury to the axillary nerve the extension of the deltoid split should not be made more than 5 cm beyond the acromion’s lateral edge. The safety suture is placed at the level for additional precaution to prevent the deltoid split propagation. At the time of insertion of the ortho implants by using this approach, the plate can be kept close towards the bone for avoiding trapping of the axillary nerve between the bone and plate.
The radial nerve can also be found close to the lateral aspect of the distal humerus. A literal application of the long plate can result in the injury to the radial nerve in the distal portion of the humeral shaft where it also pierces the lateral intermuscular septum which is distal to the insertion of the deltoid. Due to the tip of Hohmann retractor, the nerve is also at high risk of compression to the lateral aspect of the shaft of the humerus, which results in the exposure of the distal humerus at the time of application of long bone plate for osteosynthesis. This is the result that army retractors are considered to be safer to use than Hohmann retractors.
In case of the severe lateral displacement of the head fractured they seem to be less suitable. Also in the dislocation with severe displacement fracture unless they can give effective results in the young patients along with the use of closed reduction method.
The relative contradiction is severe osteoporosis, and in such cases, even the stable angular Ortho Implants can also not provide the desired stability for ensuring fracture union.
The important landmark is served by the tendon of the long head of the biceps which lies in the groove between greater and lesser humerus tuberosity. There are also chances that it can get trapped between the bony fragments of the proximal humerus and can result in the prevention of close reduction.
The lateral ascending branch for the anterior humeral circumflex artery is the intertubercular groove which also carries the main blood supply from the upper humeral head part. The avascular necrosis can be led by the damage of this artery.
The proper distinguishing between the fractures of anatomical humerus neck from the surgical neck fractures is required. In the case of the anatomical neck fractures, the frequent disruption of the main head fragment can be seen which increases the chances of avascular necrosis. On the other hand, this risk can not be found with surgical neck fractures as there is no intact blood supply.
An obstacle is formed by the insertion of the deltoid in the lateral aspect of the proximal shaft for the laterally applied long bone plate passage. The twisting of the plate at 90° is required to pass from the deltoid insertion in the helical shape for the proximal humerus of lateral aspect on to the distal half of the anterior aspect.
It is a bit difficult to reduce the proximal fractures of the humerus with displacement because the muscle attachments exert a deforming force to the shaft and humeral tuberosities.