General Orthopedics CHAPTER 1

In 19th century three landmark discoveries in surgical field which made surgeries safe, painless and enthusiastic were development of principles of antisepsis by Sir Joseph Lister (Fig. 1.2), the discovery of ether anesthesia in 1846 by William Morton (1819–1868) and the invention of X-rays by Wilhelm Konrad Roentgen (1845–1923). Discovery of X-rays revolutionized the way of making diagnosis in orthopedic cases. Another vital contribution which modernized the management of fractures was invention of plaster of Paris (POP) bandage by Antonius Mathysen in 1851. In 20th century World War I and II contributed a lot to development of core orthopedics. World wars produced countless number of patients requiring amputation, debridement, fracture management, tendon surgeries, etc. In fact many great orthopedic surgeons were military surgeons like Sir Robert Jones, Gerdhard Kuntscher, Antonius Mathysen to name few of them. In world war II, there were less numbers of amputations, fewer infections, less gangrene cases and better fixations of fractures because of the lessons learnt from World War I. Now the scope of orthopedics has extended beyond fracture fixation and deformity correction and many specialty branches have emerged like spine surgery, orthopedic oncology, pediatric orthopedics, sports medicine, reconstructive orthopedics (joint replacement), etc.

Bone matrix consists of organic and inorganic components. Organic component includes collagen fibers (mostly Type I collagen). Inorganic matter is composed mainly of calcium and phosphorus in a crystalline form called “hydroxyapatite”. Bone also contains other minerals in small amount, i.e. magnesium, potassium, strontium and ferrous salts, etc. Organic matter gives the bones its flexibility and elasticity while inorganic matter gives the strength and hardness to the bones. Composition of bone is given in Box 1.1.

A typical long bone derives its blood supply from nutrient artery, epiphyseal vessels and periosteal vessels. Nutrient artery supplies the diaphysis and metaphysis and epiphyseal region is supplied by epiphyseal vessels. Periosteum is richly supplied by periosteal vessels which also supply the outer cortex. If nutrient artery is damaged periosteal vessels are usually sufficient to nourish the bone. Bones can be classified based on anatomy and structure (Table 1.1).

Cortical bones are long bones of the body like femur or humerus and the small bones of hand and foot like metacarpals and metatarsals. Long bones of a child (Fig. 1.12) are divided into epiphysis, physis or growth plate, metaphysis and diaphysis. Epiphysis, physis and metaphysis are present at both ends. In mature bone epiphysis fuses with metaphysis and growth plate gets replaced by bone.

Germinal zone provides the developing chondrocytes which divide and get organized into columns in proliferative zone. Both germinal and proliferative zones are rich in extracellular matrix. In hypertrophic zone chondrocytes stop mitoses and undergo hypertrophy. This is the weakest zone of physis and most physeal injuries occur through this plane.

Physis is connected to epiphysis and metaphysis by the zone of Ranvier and perichondral ring of LaCorix. Zone of Ranvier contains germinal cells, which is responsible for circumferential growth of physis. Ring of LaCorix is a fibrous structure that is connected with zone of Ranvier and periosteum of metaphysis.

The Haversian canal surrounds the blood vessels and nerves cells throughout the bone and communicates with the osteocytes in the lacunae through canaliculi.

“Volkmann's canals” run perpendicular to the “Haversian canals”. They interconnect the Haversian canal with each other and the periosteum. These canals allow for the transfer of nutrients.

Primary ossification centers appear in the cartilage during the fetal development. These are responsible for the formation of diaphysis of the bones. Secondary ossification centers mostly appears after birth and are responsible for the formation of epiphysis of the long bone and the extremities of flat and irregular bones.

In contrast to cartilage, bone grows only by appositional growth. Longitudinal growth which occurs before maturity is due to cartilage proliferation in the epiphyseal and metaphyseal areas of long bones, before subsequently undergoing mineralization to form bone. Inner layer of periosteum (cambium layer) contains osteoprogenitor cells which develop into osteoblast. These osteoblast secret new bone matrix and increase the thickness of bone.

In AO classification each major bone is given a number (Fig. 1.15) like humerus, forearm bones, femur and leg bones have been assigned 1, 2, 3 and 4 respectively. Each long bone is divided into three parts or segments; proximal segment, diaphysis and distal segment which are assigned 1, 2 and 3 number respectively. Each part is further divided into types (Table 1.4).

Types of proximal and distal segment fractures are classified as:

Types of diaphyseal fractures are classified as:

Each type is further divided into groups and subgroups which differ from bone to bone.

Delayed union of fracture is defined as when fracture takes more than usual time to unite depending on the type and site of fracture, but shows some progression towards union over time. Most orthopedic surgeons do not consider nonunion of fracture of shaft of long bones to happen before 6 months.

Apart from surgical methods biophysical methods (Box 1.5) have also been used in treatment of delayed and nonunion with varying success.

Additionally, the graft may be described as cortical, cancellous, corticocancellous and osteochondral (bone and cartilage piece).

The graft may be vascularized with its own blood supply (vascularized bone graft) or it may be nonvascularized (free grafts). The vascularized bone grafts can be harvested in two ways. One is to take a bone (usually fibula) and keep its blood vessel intact (free vascularized bone graft) and anastomose the same to a vessel at the recipient site. The other is to take a bone along with an attached pedicle of muscle such that the vessel of the muscle is kept intact (muscle pedicle bone graft). This bone can be transplanted to a nearby site and the muscle's vessel continues to supply the bone.

Contact healing is seen when fracture ends are closely approximated to each other without any gap. Osteoclasts at one end of fracture cause bone resorption to form so called cutting cones such that the fracture gap widens initially. In these cones osteoclast cut by osteoclasts lay down new bone.

Figure 1.20 is showing in series radiological progress in a uniting bone.

Mnemonic SALTR is useful in remembering this classification (Table 1.8).

One disadvantage of BB splint is that ambulation of patient is difficult on it.

Indications for use of a splint are as follows:

Countertraction is the pull acting to offset or oppose primary traction force used for the reduction and to maintain the reduction. Depending on the force providing countertraction the traction may be:

Usual sites of skeletal traction are upper third tibia, distal third tibia, supracondylar femur, and the calcaneum in fractures of the lower limb. Olecronon, second and third metacarpals are usual sites in upper limb for passage of pins for skeletal traction.

Orthopedic trauma patients are often victims of high-velocity road traffic accidents and may sustain multiple injuries. Some injuries may be life threatening and need immediate intervention before the definitive treatment of fracture is begun (save life, then save limb, then save joint, then save function). ATLS guidelines provide comprehensive and speedy management of such injuries (see Chapter 2 for detail).

Tscherne graded the soft-tissue injury associated with closed fracture in four grades (Table 1.11).

Soft-tissue injury does not mean injury to only skin and muscles. Look also for blood vessels injury (signs of 27ischemia), nerve injury (paresthesia, sensory loss, motor weakness), ligament injury (joint instability), etc.

In Grade 0 or I injuries the focus is on treatment of fracture only. However in Grade II or III injuries outcome of fracture management depends upon timely and effective dealing with soft-tissue injury. Limb should be splinted to provide rest to injured tissues and put on traction to keep the fracture aligned. Elevation of the limb helps in subsidence of swelling. Appearance of wrinkles around fracture (Wrinkle sign) is a good sign of soft-tissue recovery and time for definitive fracture fixation. Always keep an eye with high suspicion on the development of compartment syndrome in both closed and open fractures. Out of proportion pain and pain on passive stretching of muscles are the earliest features. Timely management is the only key to save the limb in compartment syndrome. Management of open fractures is discussed in detail in Chapter 2.

Two main methods of fracture reduction are closed reduction and open reduction.

Fractures that mostly require open reduction are listed in Box 1.8.

Fiber cast is now available, which is light weight, radiolucent and impervious to water but costlier than POP cast. In acute displaced fractures, plaster cast is preferred because molding of plaster cast according to body contours is easier than fiber cast.

Some common fractures where cast is usually a preferred method of immobilization are given in Box 1.9. Commonly used cast methods are tabulated in Table 1.12.

Functional cast bracing provides less support to fracture than conventional cast so it is applied after 2–3 weeks when fractured ends become sticky and pain and swelling subsides. Early weight bearing is allowed with painless minor movement at fracture site. Thus functional cast bracing prevents joint stiffness, speeds-up rehabilitation and promote osteogenesis and union.

31Pin site infection is most common complication. Daily pin care with saline cleaning and betadine dressing of the pin tract should be done. In severe infection, pin is removed and new pin is inserted elsewhere. Thorough knowledge of neurovascular anatomy is necessary to avoid neurovascular injury during pin insertion. During distraction if sensory symptoms appear, rate of distraction is slowed or even stopped until symptoms disappear. Proper splinting and physiotherapy is necessary to prevent soft-tissue contractures. Regular radiological examination of the whole limb should be done to judge the consolidation at corticotomy site and also for earliest detection of subluxation or dislocation of adjacent joints.

Internal fixation is the rule for all fractures that are treated by open reduction where the complete treatment is called as open reduction and internal fixation (ORIF).

However, in some special situations internal fixation can also be done in some fractures that have been reduced closed [e.g. while nailing a long bone (Fig. 1.40)]. Here the treatment is called as closed reduction and internal fixation (CRIF) as skin incision being away from fracture site does not drain the hematoma (so closed reduction) while the fracture is fixed with an implant that lies inside the skin (internal fixation).

Classical examples of closed reduction (hematoma not drained) and internal fixation (implant inside the skin) include:

Fractures where tension band principle is commonly used are listed in Box 1.11.

A treatment algorithm for management of fracture is given in Flowchart 1.1.

Stress fractures must be differentiated from Harris lines/Park lines/growth arrest lines (Fig. 1.49) which are bilateral symmetrical dense trabecular metaphyseal lines mostly seen in rapidly growing bone ends.

A detailed workup (Box 1.14) of the patient with suspected pathological fracture should be done including search for occult primary. If investigations fail to reveal the cause of pathological fracture, biopsy should be done to establish the diagnosis.

Metastatic pathological fractures often fail to unite and require internal fixation with intramedullary rod or long plate with addition of bone cement to fill the defect or replacement of affected bone with prosthesis. Joint arthroplasty is a favorable option for lesion near the joint. For involvement of large area of bone often replacement of whole bone with tumor prosthesis (megaprosthesis) is required.

Treatment of these fractures is challenging due to poor bone stock and presence of prosthesis poses difficulty in internal fixation. Displaced fractures with stable prosthesis are usually treated with ORIF with locking plates. Loose prosthesis needs to be replaced by revision arthroplasty.

Uses of X-ray in orthopedics are given in Box 1.15.

High-frequency high-resolution transducer is used (8–13 MHz) for musculoskeletal ultrasound. A Doppler ultrasound can identify vascular flow in channels and also measure the speed.

Uses of ultrasound in orthopedics are given in Box 1.16.

Uses of CT scan in orthopedics are given in Box 1.17.

Uses of MRI in orthopedics are given in Box 1.18.