AOT Basic Principles Course Principles of diaphyseal fracture management—what is important in treating these fractures? Published: July 2013 Juan Manuel Concha, CO AOT Basic Principles Course

Learning outcomes Describe principles of diaphyseal fracture management Explain different mechanisms of injury and how the force applied influences the fracture and associated soft-tissue injury Select appropriate type of stability and implant according to AO/OTA fracture and soft tissue classification Describe pitfalls in achieving absolute stability and relative stability according to Strain Theory Understand the concept of the working length of plates and IM nails Teaching points: Integrate principles of humeral, tibial, and femoral diaphyseal fracture management in this lecture. Discuss the biological requirements of a diaphyseal fracture; the need for axial, rotational, and angular alignment; mention IM nailing as generic option with and without reaming. This must not be a specific implant related lecture.

Relationship between trauma, soft tissues, and type of fracture There is a direct relationship between the energy that causes the fracture, soft tissue, and radiographic representation. The condition of the soft tissue is crucial to defining the time of surgery and the fixation. On the other hand the general patient condition must be kept in mind. First save lives, then save limbs.

Soft tissues Condition of the soft tissue is directly related to the severity of the fracture Condition of the soft tissue is crucial to define the initial treatment and the moment of definitive fixation

The shafts are different and there is no unique menu to suit all The shafts are different and there is no unique menu to suit all. However, there are some principles that can be considered for all of them. 12 22 32 42

In shaft fractures of the humerus, it is possible to obtain good results even with nonoperative treatment. While for the femoral shaft, surgical management is indicated with relative stability the most suitable option.

Tibial shaft fractures can be treated both with closed methods or surgical treatment.

The forearm is considered a joint where anatomical reduction is required for normal function. Here anatomical reduction and absolute stability is indicated in order to restore pronation and supination.

Assessment of patient History Physical examination: Neurovascular damage Compartment syndrome especially in polytraumatized or comatose patients X-rays including adjacent joints, opposite limb

Early mobilization Avoidance of fracture disease Shorter hospital stay Earlier return to work/society Control costs Decrease some complications

Reduction and fixation techniques Reduction may be direct or indirect Direct reduction is usually indicated if anatomical reduction is needed Indirect reduction is less traumatic to soft tissues Nailing: Load-sharing is ideal for diaphyseal fractures of the tibia and femur Plating: Load-bearing is good for metaphyseal and articular extensions External fixation: Gold standard in severe soft-tissue problems/temporary device (damage control orthopedics) Usually not a choice as definitive fixation

Type of stability in diaphyseal fractures Absolute Relative

Absolute stability Simple fractures A B Forearm fractures Soft tissues in good condition Anatomical reduction Absolute stability means anatomical reduction and interfragmentary compression, which can be obtained with plating and screws. Conventional compression plate fixation, using techniques of absolute stability leading to direct bone healing, has generally been recommended for operative fracture treatment since Danis’ and the AO group’s pioneering work in the mid-20th century. Today, this approach is being challenged by less invasive, so-called biological, methods of fracture fixation. Nevertheless, osteosynthesis with plates providing absolute stability still has an important place in fracture treatment.

Simple fracture patterns are best reduced anatomically and fixed with absolute stability using a combination of lag screws and protection plate. Axial compression can also be generated with the LC-DCP. Prebending of the plate is necessary to obtain an even distribution of the compressive force. A protection plate is a plate that reduces the load placed upon the interfragmentary screw fixation, protecting it from failure. In meta-/epiphyseal split fractures, lag screw fixation often needs to be combined with a buttress plate to protect these screws from shearing forces. A lag screw correctly inserted in good bone generates forces up to 3,000 N. Since the same effect cannot be brought about by certain methods, lag screws should be used whenever the fracture pattern permits.

Forearm fractures require anatomical reduction and stable fixation. Interfragmentary compression and absolute stability offer the best result in terms of function.

Relative stability Multifragmentary fractures Femur, tibia, humerus Forearm only in exceptional cases Functional reduction

Length, rotation, and correct angulation avoiding varus or valgus deformities are the goal. In diaphyseal fractures, it is called functional reduction. The vascularity is preserved since fragments are not touched.

To achieve normal lower limb function and the correct mechanical axis you must achieve correct length and axial rotation.

Three different methods to obtain relative stability: external fixator, bridging plate, and intramedullary nailing (IMN).

Callus formation is the result Callus formation is the result. Normal function can be anticipated if correct relationships of adjacent joints is restored and fixation is stable enough to allow early active use of the attached muscles and the joints. Anatomical reduction of every fracture fragment is not required.

Working length (WL) The distance between the innermost screws on either side of the fracture is defined as the “working length” of the plate. A longer working length leads to greater fracture mobility due to reduced construct stiffness. A short working length decreases the motion in the fracture gap, but the same displacement of the fracture creates a higher stress on the plate, which increases the risk of fatigue failure. Nail Working Length: distance between the proximal and distal locking screws.

Advantages of intramedullary nailing Load sharing versus load bearing Less damage to periosteal circulation Less damage to surrounding soft tissues Indirect reduction technique is more tissue friendly Relative stability technique favors early callus formation

Advantages of intramedullary nailing Less problematic in osteopenia Early weight bearing which promotes healing Prevents disuse osteoporosis Easier removal of implant Less chance of refracture after implant removal

Advantages of plates and screws Less damage to endosteal circulation Greater control of fracture position especially in metaphysis and juxta-metaphyseal fractures Indirect reduction available in MIO technique Relative stability possible with bridge plating technique

Bridging plates relative stability examples: Intraarticular fracture extending into knee joint Associated ipsilateral proximal femoral fracture Vascular repair associated with distal-third femoral fracture Periprosthetic fractures When nailing is contraindicated Biological reduction and plating

Postoperative management Muscle rehabilitation Active range of motion exercise Continuous passive motion (CPM) Load transmission good for bone growth Prolonged nonweight-bearing walking— osteopenia, muscle wasting, cartilage atrophy

Take-home messages Assessment of injury soft tissues and fracture classification Indications for operative treatment Difference between functional and anatomical reduction Absolute and relative stability Choice of implants