CT provides excellent images of bone anatomy (Fig. 27.1) and can be used to supply three-dimensional images to help in the reconstruction of complex fractures. The thin axial slices are particularly useful as a guide for obtaining biopsy specimens

Fig. 27.1 A three dimensional CT showing a iliac wing fracture.

Magnetic resonance imaging (MRI)

MRI (Fig. 27.2) provides excellent images of soft tissue, joint and bone pathology without exposure to radiation. It is widely used in virtually all branches of orthopaedics for diagnosis and preoperative planning.

Fig. 27.2 An MRI scan of a shoulder through the level of the acromioclavicular joint and the glenohumeral joint.

Bone scans

These can be used to assess a number of bone conditions, including infection and tumours (Fig. 27.3).

Fig. 27.3 An example of a bone scan showing increased uptake of radioactive tracer in the clavicle: in this case, indicative of infection.

There are also increased areas of uptake in the shoulders and sternum.

Description of deformity

With patients in the anatomical position (i.e. lying on their back with their palms pointing up to the ceiling), limb deformities are described relative to the midline (away = valgus, towards = varus) and to the alignment of the limb below the joint or deformity. For example, with respect to the knees, bowleggedness is a varus deformity, while knock-knees are a valgus deformity (Fig. 27.4). With the patient viewed from the side, there is a range of descriptive terms available. For example, hyperextension of the knee joint is known as recurvatum (Fig. 27.5). The three types of spinal deformity are:

• kyphosis: forward flexion (‘the kyphotic kisses his knees’).

• lordosis: the opposite, extension, or bent-over-backwards deformity; this represents the normal alignment of the lumbar and cervical spine.

• scoliosis: a sideward deformity that is normally associated with a degree of rotation (Fig. 27.6).

Fig. 27.4 Historical slide of children, showing deformities of the knees.

All the children show valgus knee, i.e. knock-kneed, deformities.

Fig. 27.5 A recurvatum deformity of the knees with hyperextension.

Fig. 27.6 An X-ray of the thoracic and lumbar spine, showing gross scoliosis of both.

Osteoarthritis: degenerative disease of the joints

Osteoarthritis (OA) of a joint may occur as a primary idiopathic condition or secondary to problems such as malalignment, intra-articular fractures or over-stressing (obesity, overuse). In some patients, there is a strong genetic component. OA may occur in any joint (shoulder, elbow, wrist and hands) but predominantly affects those that are weight-bearing (hip and knee) (Figs 27.7 and 27.8). Idiopathic OA is generally of slow onset and affects the elderly. Secondary OA can affect the young and may develop quite rapidly when a joint injury leads to loss of articular cartilage. On plain X-ray, OA is associated with:

• joint space loss due to thinning of articular cartilage

• sclerosis of the joint surface, with the development of increased density of the bone just under the joint space

• osteophytes

• cystic change.

Fig. 27.7 Bilateral knee osteoarthritis.

The left knee (on the right-hand side in the illustration) shows predominantly lateral wear and has a valgus deformity. The right knee has osteoarthritis of both medial and lateral compartments.

Fig. 27.8 Osteoarthritis can affect any joint.

A Here, the first toe metatarsophalangeal joint is clearly arthritic. B Similarly, the carpometacarpal joint at the base of the thumb can also be affected.

The treatment of OA may be conservative or operative (Table 27.2). The former focuses on the use of drugs and physical methods of pain and stress relief to the joint.

Table 27.2 Management options for osteoarthritis

Non-operative	Operative
Analgesia Physiotherapy Orthotics Injections Lifestyle modifications	Osteotomy Joint debridement Excisional osteotomy Joint replacement (arthroplasty) Joint fusion (arthroplasty)

Medical management of OA

Drug therapy

Simple analgesics, such as paracetamol, with or without the inclusion of nonsteroidal anti-inflammatory drugs (NSAIDs), are the mainstay of treatment. More powerful analgesic combinations may be introduced such as codeine or morphine, if simple analgesics prove inadequate.

Off-loading

This involves the use of aids, such as a walking stick and weight loss, aimed at reducing the forces passing through the joint. In the obese, weight loss is helpful as the load across a joint is three to six times body weight. Various insoles and splints are commonly used in orthopaedics to offload joints and are fitted by an orthotist.

Injections

Introducing a mix of a corticosteroid and local anaesthetic into the joint may reduce inflammation and ease pain. Injections of compounds of hyaluronic acid are increasingly used and are designed to supplement the natural joint levels of hyaluronic acid essential to normal functioning of articular cartilage. They work best in early OA but have little, if any, effect in late-stage disease.

Other conservative treatments

Physiotherapy and hydrotherapy both have a part to play in the control of symptoms, especially in early disease. Building up lost muscle bulk (frequently lost due to reduced activity) provides the joint with an increased degree of muscular control and may lead to considerable symptom improvement. Other treatment modalities, such as acupuncture, are recognized to have a role in the management of pain associated with OA. Failure of conservative methods normally leads to consideration of surgical intervention; in the patient unfit for surgery, benefit may be gained from referral to a pain therapist.

Surgical management of OA

The main operative interventions include osteotomy, replacement and fusion. Certain joints, particularly the knee, may benefit from a more minimal approach, such as arthroscopic debridement. This may help when a patient complains of physical symptoms indicative of underlying mechanical problems, such as locking or discomfort related to meniscal problems. However in well established OA this intervention can have a limited affect.

Osteotomy

This is useful in the younger patient, in whom joint replacement may not be advisable. The aim is to change the axis of the joint, so that a portion of the joint surface that has thus far been protected from wear and tear now forms the weight-bearing area. For example, with respect to the knee, although there may be severe OA of the medial compartment in conjunction with a varus deformity, the lateral compartment may have well-preserved articular cartilage. Over-correcting the varus deformity by means of osteotomy (removing wedges of bone from the tibia), so that body weight is now largely transmitted through the lateral compartment, may lead to significant improvement in symptoms, thus delaying the need for joint replacement (Fig. 27.9). Osteotomies generally use opening wedges (adding bone), closing wedges (removing bone) or may be translational or rotational.

Fig. 27.9 An example of an osteotomy to the proximal tibia.

A The osteotomy site has been fixed by a plate and screws. B The cut of the osteotomy lies between the top two screws and the bottom three screws.

Joint replacement

The hip, knee, ankle and shoulder, and indeed almost any joint, can now be partially or completely replaced in a number of different ways with varying degrees of success.

Hemi-arthroplasty

In this operation, only one-half of the joint is replaced, leaving half of the joint intact. It is normally the natural socket – for example, the acetabulum – that is left untouched. The most common example is following fracture of the femoral neck in the elderly. Such patients usually have low demand on the joint, and the hemi-arthroplasty (Fig. 27.10) gives adequate function without risking many of the complexities of a total hip replacement.

Fig. 27.10 An example of a hemi-arthroplasty of the hip, where only the femoral part of the hip joint has been replaced.

This type of procedure is commonly used after a displaced intracapsular fracture of the hip.

Total joint replacement

This entails resurfacing of both sides of a joint (Fig. 27.11). The choice of materials for the weight-bearing surfaces varies, depending on the joint and prosthesis in question. Currently, metal against a high-density polyethylene is the most common, although new prostheses involving metal and ceramics surfaces have been developed for use in young people (Fig. 27.12). Fixation of the implants may be with cement, or by encouraging bone to grow into or onto the surface of the implant. In small joints, such as those of the hand in patients with rheumatoid arthritis, silastic may be used as a buffer or spacer between the two joint surfaces.

Fig. 27.11 A total hip replacement.

The acetabulum contains a high-density polyethylene socket that is radiolucent, with a wire to give an indication of the sockets position within the acetabulum. The femur contains a metal prosthesis. Both acetabulum and femoral components are cemented in with polymethylmethacrylate cement.

Fig. 27.12 A modern total hip replacement showing a cobalt chrome femoral stem, ceramic femoral head and a polyethlene acetabular cup. Courtesy of Stryker.

Arthrodesis

Any residual cartilage is removed down to bleeding cancellous bone before the joint is rigidly fixed resulting in complete loss of movement (Fig. 27.13). Small joint fusions of toes and fingers are the most common examples. Fusion of a large joint, such as the hip or knee, will have a significant effect on mobility and will add additional stress on the joints above and below. Thus, pre-existing OA in the joints either proximal or distal to the joint being considered for fusion is a relative contraindication.

Fig. 27.13 An arthrodesis of the ankle and subtalar joint.

The joint has been excised and the bone surfaces have been brought together. An intramedullary nail has been used to hold the position.

Interposition arthroplasty

The joint is excised and the residual space is filled with autogenous or allograft material. For example, the trapezium in the hand can be excised and the space filled with a rolled-up tendon, such as palmaris longus.

Excision arthroplasty

The joint surfaces are excised, giving a ‘joint’ formed of scar tissue. For example, in Keller’s procedure, the first metatarsal- phalangeal joint is excised to treat hallux rigidus; in a Girdlestone’s operation, the femoral head is excised. The hip heals in a very shortened position and patients require a significant shoe raise to equalize the length of their legs, but the joint is relatively pain-free. Nowadays, this would be regarded as a salvage procedure after, for example, removal of an infected hip prosthesis.

Rheumatoid arthritis and inflammatory disease of joints

Rheumatoid arthritis is a chronic systemic inflammatory disorder that can affect many tissues and organs, but principally attacks synovial joints leading to destruction of articular cartilage. Clinically RA can be differentiated from OA in that it presents with a symmetrical poly-arthropathy affecting the small joints of the hand, feet and cervical spine but affect larger joints such as the hip and knee.

Radiologically, there is often peri-articular osteopenia, soft tissue swelling, loss of joint space and as the disease advances, there may be bony erosions and subluxation of the joints.

The majority of patients with RA and other inflammatory disease of joints have been assessed and treated by a rheumatologist prior to orthopaedic referral. Often referral for surgical intervention is made when there has been a failure of medical treatment with disease modifying anti-rheumatic drugs (DMARDs). Orthopaedic treatment options range from synovectomy to joint fusion or replacement.

Other inflammatory disorders which can present to the orthopaedic surgeon include gout and pseudogout, Systemic Lupus erythematosus (SLE) and Ankylosing Spondylitis. Knowledge of these conditions and their management is essential for the practising orthopaedic surgeon.

Bone and joint infection

Primary infection

Primary infection of bones (osteomyelitis) or joints (septic arthritis) is rare and secondary to haematogenous transmission of microorganisms. Primarily a disease of childhood, these infections present with acute pain, swelling, loss of function (reluctance to use the limb), and often follow a bout of respiratory or skin infection. The most common sites are the long bones and joints of the lower limb. In children, 90% of cases are due to Staphylococcus aureus. By contrast, adults may present with rare and unexpected organisms as a result of other co-morbidity, immunosuppressant therapy, indwelling prosthetic material (e.g. renal dialysis catheters) or intravenous drug abuse. The importance of obtaining positive microbiology from blood cultures, aspirations or bone samples prior to starting antibiotics cannot be over-emphasized. Poorly treated acute osteomyelitis may lead to chronic osteomyelitis which is associated with a life-long risk of exacerbations or sinus formation and septic arthritis may lead to articular cartilage destruction and secondary osteoarthritis.

Secondary infection

Osteomyelitis secondary to trauma (open fracture) or operation (insertion of metalwork) is relatively more common than primary osteomyelitis. Dead bone (sequestrum) acts as a reservoir of infection and, although this may be walled off by new bone growth (involucrum), infection, once established, may lie dormant for many years before reactivating. Orthopaedic operations (without preceding trauma) are a relatively rare cause of true osteomyelitis (although any foreign prosthesis placed in bone may become infected). Infection of an implant or fracture fixation device may be very difficult to eradicate and is the most common reason for implant failure.

Overview of joint replacement surgery

Knee and hip replacements are the most common procedures, although shoulder, elbow, ankle, wrist and finger replacements may all be performed. With regard to the knee, there has also been a move away from traditional total joint replacement towards replacing that part of the joint affected by OA (Figs 27.14 and 27.15). These advances permit less invasive surgery and quicker recovery. Successful joint replacement surgery is associated with low infection and revision rates for prosthetic failure: ideally, less than 95% at 10–15 years (Figs 27.16 and 27.17). Revisional joint replacement surgery is more complex and associated with greater rates of complications and further device failure. Postoperative infection is divided into early and late. Early infections are usually purulent, occur within the first few weeks, and may be eradicated with early debridement and appropriate antibiotics, but may necessitate removal of the prosthesis. Late infection is usually due to more indolent organisms such as Staph. epidermidis, may follow a bacteraemia or colonization at the time of implantation, and often presents as early loosening which leads frequently to revisional surgery.

Fig. 27.14 This is a unicompartment joint replacement.

A local resurfacing of the tibia and the femur for osteoarthritis of the medial compartment of the knee joint.

Fig. 27.15 A normal knee replacement, showing the resurfacing of the femur with a femur-shaped component.

The tibial component can be seen as a metal base plate that holds the plastic bearing surface, which creates the gap between the femur and tibia.

Fig. 27.16 A revision knee replacement.

As can be seen when contrasted with the normal knee replacement in Figure 27.15, this is more complex and requires stems that go up the femur and down the tibia to create extra stability.

Fig. 27.17 Failure of a total hip replacement.

The hip is surrounded by heterotopic ossification and the cement mantle (surrounding the femoral prosthesis) has started to come loose.

Overview of arthroscopic surgery

Arthroscopic techniques have been adopted in most areas of orthopaedics. The ability to repair soft tissues, place suture anchors into bone, and drill bone through the scope has permitted the development of arthroscopic-assisted:

• repair: menisci in the knee and the rotator cuff in the shoulder

• stabilization of unstable joints: the recurrently dislocating shoulder

• joint fusion: ankle, subtalar joint

• ligament reconstruction: anterior cruciate ligament.

• debridement – removal of infected tissue, loose or impinging bone.

Paediatric orthopaedic surgery

The growing child presents particular challenges, and certain disease processes may only occur at certain stages of childhood. Surgery must be planned carefully so as not to interfere with the growth plates. Parents often require strong reassurance.

Dysplastic disease of the hip (DDH)

This is more common in breech deliveries, the first-born and females. It is due to inadequate development of the hip joint (Fig. 27.18), and presents with varying severity. When diagnosed in the newborn, milder forms in which the femoral head has a tendency to sublux from the acetabulum, are best treated using a ‘harness device’ that allows freedom of movement while holding the femoral head in the joint. More severe forms, where there is actually fixed dislocation, may require operative reduction and occasionally osteotomies.

Fig. 27.18 Dysplastic disease of the hip, showing a dislocated left hip.

Perthes’ disease

This is a self-limiting disease due to avascular necrosis of a portion of the developing femoral head. The cause is unknown but disease tends to occur between 4 and 10 years of age and is more common in males. An early stage of inflammation and synovitis is followed by a regenerative stage, in which the necrotic area is replaced by viable bone (reossification). Clinically, the onset is slow and the child complains of pain and limping. Treatment aims to relieve pain and prevent deformity while the femoral head is healing. Prognosis depends on the age of onset, degree of involvement of the femoral head, and adequacy of treatment; in general, the older the patient, the worse the outcome.

Cerebral palsy (CP)

This is a disorder of movement and posture due to a defect in the developing brain. CP is usually caused by adverse birth events, such as hypoxia and infection, and comes in a variety of forms (spastic, athetoid, ataxic, mixed) and extents: monoplegia (one limb – rare), hemiplegia (one side of the body affected), diplegia (both lower limbs affected), tetraplegia and quadriplegia. Contractures can be treated with regular stretching, botulinum toxin, tendon release or muscle transfer. Bony abnormalities may require osteotomy.

Slipped upper femoral epiphysis (SUFE)

The femoral head epiphysis weakens and the head slips, resulting in the upward and anterior displacement of the femoral neck. SUFE is of unknown aetiology. It usually develops between 10 and 16 years old, and is most common in boys at the time of their growth spurt; it is found more frequently in the short, fat, hypogonadal or hypothyroid child, suggesting a hormonal influence. It is a bilateral condition in 25% of cases. It frequently presents with referred pain to the knee and is thus commonly misdiagnosed as a knee problem. The condition may present as a chronic slip that occurs over a few months, or acutely after a seemingly minor episode of trauma. Treatment involves pinning of the slip, using a screw, together with corrective osteotomy if there is any significant residual deformity after healing. The contralateral side is generally fixed prophylactically and there is a risk of avascular necrosis in severe slips.

Congenital club foot (talipes equinovarus or ctev)

This is an idiopathic fixed deformity of the foot, which is frequently bilateral. There may be a genetic component and it is twice as common in males. Simple methods of treatment include strapping and splinting for minor deformities, and surgical correction where conservative methods have failed.

Scoliosis

This can be divided into structural and non-structural. ‘Non-structural’ scoliosis is secondary to some other problem (e.g. inequality of leg length, lumbar disc prolapse) and disappears when the underlying cause is removed. Structural scoliosis can be caused by a variety of conditions, although 90% of childhood cases are idiopathic. Unlike the non-structural form, there is an accompanying rotational deformity. The usual presentation is between 10 and 13 years of age, and the condition is more common in females. Usually, it is asymptomatic and, if there is pain, one should think of other reasons for the scoliosis (e.g. tumour). The treatment of scoliosis is complex but involves spinal bracing and surgical intervention.

Angular deformities

Genu varum (bowlegs) is often seen in very early childhood. It often corrects and tends to genu valgum (knock-knees) between 18 months and 3 years; this then corrects by 4–7 years. It is important not to forget alternative diagnoses, such as rickets and Blount’s disease (idiopathic abnormality of the upper medial tibial epiphysis).

Musculoskeletal tumours

Musculoskeletal tumours may arise from cartilage, skeletal muscle, synovium or bone, and may be benign or malignant. They are rare, and usually present with deep-seated pain that often continues into the night, or a soft tissue swelling. There may be a history of incidental trauma, to which the symptoms are frequently attributed. High-grade tumours may have a short history (of several months), whereas the more benign lesions have a prolonged course. Clues to malignancy include rapid growth, fracture through unusual bone, destruction of the bone cortex and invasion into the soft tissues. Primary bone tumours are rare; they occur largely in the second decade of life and frequently affect the metaphysis. The most common malignant tumour is osteosarcoma, 50% of which will occur around the knee. The next most common is Ewing’s sarcoma. Once a bone tumour is suspected, the patient should be referred immediately to the regional specialist treatment centre for biopsy, staging and definitive treatment. Over the last decade, advances in adjuvant treatment (chemotherapy prior to and following surgery) have resulted in considerable improvements in long-term prognosis.

The upper limb

The shoulder

Anterior dislocation

Anterior shoulder dislocation is the commonest form of dislocation, and can be associated with or without fracture (Fig. 27.19). The cause of an anterior dislocation is often traumatic. Treatment involves immediate reduction with analgesia and sedation using Kocher’s, Milche’s or Hippocratic methods. Patients require to be immobilized in a sling and a check radiograph is mandatory to confirm reduction and exclude a fracture. Instability following shoulder dislocation is common in young males and in this group of patients an arthroscopic examination and stabilization may be required if there is a high risk of recurrence.

Fig. 27.19 A fracture dislocation of the humeral head, showing the humeral shaft and head as separate pieces, as well as portions of the greater tuberosity.

All are separate from the normal anatomical position of the femoral head, and the glenoid can be clearly seen in the background of the X-ray.

Impingement syndrome

Weakness through disuse, degeneration and tearing of the rotator cuff muscles (supraspinatus, infraspinatus, subscapularis) predisposes to superior subluxation of the humeral head against the acromion, leading to so-called impingement pain. Steroid injections and physiotherapy may be effective. If there is a bony spur at the front of the acromion that is contributing to the impingement, this can be removed arthroscopically (subacromial decompression).

Rotator cuff disease

Rotator cuff disease is a degenerative process affecting the tendons that make up the rotator cuff (supraspinatus, infraspinatus, subscapularis and teres minor). In particular the avascular region near the insertion of the supraspinatus tendon can be affected. Complete or partial tears may be present in up to 50% of the population over 60 years of age but most are asymptomatic. Acute rotator cuff tears may occur as a result of trauma or chronic impingement. Patients most commonly present with pain around the shoulder and weakness particularly on shoulder abduction.

Treatment options include conservative management with physiotherapy and corticosteroid injections or surgical (arthroscopic repair with a subacromial decompression).

Osteoarthritis

Arthritic changes can affect the glenohumeral or the acromioclavicular joint (ACJ) and may give rise to prolonged pain associated with shoulder movements. ACJ OA is treated with either injection or excision of the joint. OA of the glenohumeral joint may be secondary to avascular necrosis of the humeral head or as result of previous fracture of the proximal humerus. If conservative methods fail, glenohumeral joint OA can be treated with either shoulder replacement or resurfacing.

The elbow

Tennis and golfers’ elbow

The most common pathologies to affect the elbow are inflammation of the lateral (tennis) or medial (golfers’) epicondyle at the point of insertion of the muscle mass. The mainstays of treatment are bracing and strapping, injections and physiotherapy. If these fail, operative release of the tendinous insertion may be warranted.

The cause of pain around the wrist can be a challenging diagnosis to make. Common causes include those secondary to trauma such as a distal radius fracture (Colles fracture) or a scaphoid fracture (see below); degenerative causes such as rheumatoid arthritis or osteoarthritis and those secondary to inflammation affecting the tendon sheaths such as De Quervain’s disease which affects the abductor pollicis longus and extensor pollicis brevis tendons.

Carpal tunnel disease

The median nerve is compressed, either by the tunnel itself or by its contents: for example, by a synovial swelling. Symptoms include pins and needles or sensory loss in the territory of the median nerve (a variable area of supply normally including the palmar aspect of the thumb, index and middle fingers, with a variable amount of the ring finger involved). Treatment options include night splinting and injection or surgical decompression of the tunnel by releasing the flexor retinaculum overlying the median nerve.

Trigger finger

Thickening of the flexor tendon causes it to jam under the pulley system that would normally allow the tendon to slide backwards and forwards. Injection around the tendon or release of the first pulley results in a cure of the condition.

Dupuytren’s disease

Thickening of the palmar fascia draws the fingers (predominantly the fourth followed by the fifth) into a flexed and deformed position, resulting in disability and loss of function. It is more common in diabetics, epileptics and can often be associated with previous trauma to the area affected. The condition mainly affects men over the age of 40 years. Surgery is considered if there is significant disability affecting the fingers. This involves either dividing the thickened tissue (fasciotomy), dissecting and removing the thickened fascial bands alone (fasciectomy) or with the overlying skin (dermo-fasciectomy), taking great care to preserve the associated nerves and blood vessels. In severe cases, amputation of the little finger may be the best line of treatment.

The lower limb

The hip joint

The main problems are the late complications of young persons’ diseases of the hip and OA. Treatment ranges from conservative methods through osteotomy to joint replacement surgery. Where a remnant of articular surface remains intact, osteotomies may be extremely useful to realign usable portions of cartilage against each other.

Avascular necrosis of the femoral head

This typically presents with severe pain, often at night, and initial X-rays may appear normal. MRI is usually diagnostic. If the head has not collapsed, it is usually decompressed via a channel drilled up the femoral neck (core decompression). If the head has collapsed, then total joint arthroplasty may be the treatment of choice.

Hip arthroscopy

Recent developments in hip arthroscopy have led to a greater understanding of the nature of adolescent and adult hip pathologies and their management, particularly in athletes and other young individuals with hip injuries. It remains to be seen whether early diagnosis and treatment of acetabular labral tears or lesions of the cartilage using this technique will curb the progression of osteoarthritis.

The knee joint

History

The history often points to the likely diagnosis. Inability to carry on playing sport immediately after an injury hints at a ligament rupture. Rapid swelling within a few minutes or hours suggests a major injury within the knee. A large haemarthrosis occurring within the first few hours after an injury indicates a major ligament tear, a peripheral tear of the meniscus or an osteochondral fracture. All of these conditions require further evaluation. Ligament injuries may present in clinic with a history of preceding injury and subsequent instability. Often, this is a feeling of an inability to trust the knee on trying to move from side to side, although the knee may feel stable when the person is running in a straight line. Regular episodes of giving way are thought to accelerate the development of OA. Patterns of injury do tend to coexist and may be related to certain mechanisms of injury.

Meniscal injuries

These are relatively common and can be divided into two major groups. Younger patients are more likely to have a purely traumatic tear of the medial meniscus. As the patient gets older, degenerative tear of the lateral meniscus is more frequent. Symptoms may consist of swelling and localized pain in the knee, particularly around the joint line. If a fragment of meniscus is loose within the joint space, true locking may occur, with a loss of ability to extend the knee.

Osteoarthritis

This is very common and may affect the whole of the knee (tricompartmental OA), or just particular compartments such as the medial or patellofemoral. Symptoms may be precisely localized both to precipitating events and to an anatomical site; for example, pain going up and down stairs reflects patellofemoral disease, while in isolated medial OA the pain may be well localized to the medial side of the knee. The knee lends itself to surface replacements purely of the affected parts, and isolated medial and patellofemoral joint replacements exist, as well as total knee replacements. When patients are asked for consent for replacement knee joints, it is customary to warn them that the prosthesis will last for 10–15 years but, in fact, many prostheses continue to function well beyond this limit and there is no sudden dramatic increase in the rate of revision once 10 years have passed.

The foot and ankle

Sprains of the ankle are very common – most recover, but damage to the supporting lateral ligaments may lead to instability and recurrent ‘giving way’ of the ankle. This may be associated with damage to the cartilage in the ankle.

Arthritis may occur in any of the joints of the foot – ankle arthritis is increasingly treated with an ankle replacement, but other joints are generally fused or treated non-operatively.

Foot deformities frequently occur – the most common are pes planus (flat feet with loss of the medial arch) and pes cavus (excessive arching of the foot), leading to chronic foot pain and difficulty in walking. The most common forefoot deformity is hallux valgus (more commonly known as a bunion), in which the great toe is deviated in a valgus direction at the metatarsophalangeal joint. Treatment is generally with a metatarsal osteotomy to realign the toe. Hallux rigidus is OA of the first metatarsophalangeal joint and can be treated with insoles, a fusion or a joint replacement. Frequently, the lesser toes may be deformed and are straightened using tendon transfers or fusions. Nerve entrapments are sometimes seen – Morton’s neuroma (compression of the digital plantar nerve) and tarsal tunnel syndrome (tibial nerve compression) are the most common.

Trauma and fractures

General approach

The initial assessment and resuscitation of the (multiply) injured patient follows the Advanced Trauma Life Support (ATLS) guidelines (Table 27.3) Management of the injured patient requires a team approach, and often entails joint care by a number of different specialties, from the time of initial resuscitation in the accident and emergency department right through to the definitive treatment of each injury. Certain patterns of injury can be anticipated. For example, patients who fall from a height and land on their feet may be expected to have sustained an injury to calcaneus, tibial plateau, hip and pelvis. At impact, patients tend to fall forward, often leading to spinal fractures.

Table 27.3 Advanced trauma life support guidelines

Primary survey
A	Airway with C-spine control
B	Breathing and ventilation
C	Circulation and haemorrhage control
D	Disability (neurological evaluation)
E	Exposure and environment
Secondary survey
Once the resuscitation efforts are well established and the vital signs are normalising, the secondary survey can begin. This involves a complete history and physical examination, including the reassessment of all vital signs.

Examination

Careful examination of each injured limb includes:

• Skin. Ascertain whether any skin breaks communicate with any underlying fracture.

• Circulation. The most common cause of absent pulses is kinking or compression of the artery by the fracture. Often, a reduction of the fracture (realigning the fracture into the anatomical position) or application of traction results in the return of perfusion.

• Nerves. Certain injuries may have a high associated risk of neurological injury, manifest by loss of power and/or sensation. For example, the axillary nerve is at risk from shoulder fracture dislocation and its integrity should be documented prior to reduction (see Fig. 27.19).

• Joint above and below. Often fractures can involve the joint immediately above or below. A complete examination of these joints is required as it may influence definitive treatment of the injury.

Joint dislocation

Reduction of the joint must be performed as soon as possible, either in the accident and emergency department under sedation (e.g. anterior dislocation of the shoulder), or in the operating theatre under general anaesthesia. In some cases where closed reduction fails, open surgical reduction is performed.

Fracture management

Classification

Fractures are usually classified by:

• whether they are in communication with the skin surface (open or compound) or not (closed)

• their appearance on X-ray: for example, comminuted (in multiple pieces, Fig. 27.20), spiral (where the fracture curves in a large spiral around the long axis of the bone) or transverse (straight across the bone, Fig. 27.21) This appearance usually correlates with the mechanism of injury – a twisting injury tends to cause a spiral fracture for example.

• anatomical site: for example, intra-articular (involving the joint surface, Fig. 27.22), metaphyseal, epiphyseal or diaphyseal.