Injuries of the arm
• Distal humerus fractures
Peculiarities of Humeral Shaft Fractures
• Next to clavicle, this is often the second commonest birth fractures.
• Due to surrounding thick muscles:
– Incidence of compound fractures is low.
– Thick muscles are rich in periosteal blood supply.
– Malunion remains concealed within the thick musculature (No cosmetic abnormality is seen).
– Conceals shortening of the humerus, if any.
– Wide displacements occur.
– Wide displacements increase the rate of malunion.
– Soft tissue interposition may occur causing nonunion.
• Due to the ball and socket variety of the shoulder joint above, malunion usually does not cause functional disability.
• Gravity plays a very big role in providing a sustained longitudinal traction force to the distal fragment. This helps not only in the reduction of the fracture but also retention.
• Shortening, if occurs, largely remains unnoticed because unlike its lower limb counterpart the femur, it does not produce limp and hence there is no functional impairment. • nervus radialis injury can occur before reduction and sometimes even after closed reduction thanks to it getting trapped in between the 2 fracture fragments. This is the sole fracture within the body known to point out this peculiarity.
• Gravitational forces which give the natural traction forces also may it causing distraction and nonunion.
• Muscles reduce the incidence of compound fractures but produce all sorts of displacements within the common simple fractures.
The muscles of the upper arm said the deformity. If the fracture is between pectoralis major and deltoid, the proximal fragment is adducted by pectoralis major, teres minor and latissimus dorsi, while the distal fragment is pulled upwards by the deltoid. If the fracture is below the insertion of deltoid, the proximal fragment is abducted by the deltoid while the coracobrachialis, biceps and triceps pull the distal fragment upward.
Mechanism of Injury
This may produce a transverse or comminuted fracture.
Indirect force: It is due to fall on an outstretched hand and this will produce an oblique or spiral fracture. Birth injuries: This is the second most common birth fracture after clavicle.
Its show all the signs and symptoms of a fracture. A careful neurological and vascular assessment is important. Injury to nervus radialis is common in fractures at the spiral groove or lower one-third of humerus.
Radiography of the whole upper arm including both the shoulder above and therefore the elbow below should be taken. It helps to review the extent and pattern of the fracture.
- This consists of splinting the injuries of the Arm fracture if it’s undisplaced. In the displaced fractures, splinting is done after the closed reduction under GA.
- Simple splint in birth fractures.
- Simple sling may be sufficient in young children.
- Hanging cast is useful in older children and adolescents. Here gravity aids in reduction of the fracture. They are not suitable if the level of fracture corresponds to the upper limit of the cast, because of the deforming effect of the proximal end of the cast. It is indicated in comminuted fractures of the distal third. If the cast is too heavy, it maycause distraction and consequent delayed or nonunion.
- The plaster U-splint and Co-aptation splint is sufficient in most of the situations of fractures of the proximal and middle third portions of the humerus.
- Functional cast brace: uses the muscular force to both reduce and retain the fracture. Here replacing all the modalities of conservative treatment and is emerging because the gold standard of nonoperative methods.
Did you know? Hanging cast was described by Caldwell and therefore the weight shouldn’t exceed two pounds.
• Failed conservative treatment.
• Multiple fractures and unstable fractures.
• Multisystem injuries.
• Radial nerve palsy after closed reduction.
• Pathological fractures.
• Compound fractures with vascular injuries.
• Segmental fractures.
• Intra-articular extension into shoulder and elbow joints.
• Bilateral humeral fractures.
• Brachial plexus injuries.
• Ipsilateral shoulder or forearm fractures.
- DCP plating for fractures at all levels. Still remains the gold standard. LCDCP is preferred. Radial nerve injury is a concern.
- Intramedullary fixation at middle third fractures.
- Recently in the segmental fractures, pathological fractures, polytrauma patients,proximal and distal fractures, etc.
- Multiple flexible retrograde IM nailing.
- Self-locking expandible nails are being tried.
- External fixation for open fractures. Indicated open reduction and rigid internal fixation with DCP plate and the screws is the optional method. Interlocking nail technique is now being more commonly used for comminuted fractures of the humerus.
Radial nerve injury: This is common in lower onethird fractures and is usually of a high variety. It may also be damaged in the spiral groove. Closed fractures need observation, splinting of wrist and fingers. If a nervus radialis deficit occurs after closed manipulations, immediate exploration is important .Mostly, in the injuries of the arm.
Nerve—wracking facts about radial nerve
• Commonly nerve to be injured is in fracture of shaft of the humerus.
• Incidence is 2 to 18 % at the middle 1/3rd fractures.
• Recovers spontaneously by 3 to 4 months.
• Exploration indicated beyond 3-4 month
Vascular injury: To the brachial vessels is unusual. It requires repeated assessment and prompt treatment.
Malunion: In fracture of humeral angular deformity of 20° is acceptable in the middle and distal 1/3; while in the proximal 1/3, 30° is acceptable. Thick muscles within the upper arm usually conceal the malunion.
Nonunion: Nonunion is not very common but may be seen due to the over-weight hanging cast. This requires open reduction, excision of the fibrous tissue, rigid plating and bone grafting in Injuries of the Arm.