Elective Orthopaedics

Structure of Long Bone

Bones can be classified by their shape (long vs. flat) , macroscopic structure (cortical vs. cancellous) and microscopic structure (lamellar vs. woven) . Long bones (e.g., femur, humerus, forearm, metacarpal and metatarsal bones) have three regions: epiphysis, metaphysis and diaphysis ( Fig. 11.2 ). Flat bones ( e.g., cranium, pelvis, scapula) are composed of cortical bone enclosing a minimal trabecular region.

Periosteum consists of fibrous (fibroblastic) and inner cambium (osteogenic) layers and is tightly bonded to bone by Sharpey fibres. It covers the outer surface of all bones, except at the joints of long bones. Cortical bone has a slow turnover (formation and removal) and consists of packed Haversian systems (osteons, neurovascular canals and interstitial lamellae) which give bone its strength. Cancellous bone is softer, porous, more elastic and has a higher turnover, undergoing ‘stress-dependant’ remodelling. Woven bone is immature or pathological bone. It is typically weaker, more flexible, has a high turnover rate and greater osteocyte density than lamellar bone.

General Considerations

A good clinical history and thorough examination is essential. Decision making in orthopaedics and fracture management never rests purely on x-ray or magnetic resonance imaging (MRI) scan findings. Factors to be considered before imaging include:

• Age: many fractures and orthopaedic conditions are very age specific.

• Occupation: some occupations are more likely to produce orthopaedic problems but, in addition, knowing a patient’s occupation (and hobbies) gives insight into their financial responsibilities and aspirations. Retired people too have aspirations. Being interested in your patient as a whole helps them help you with their management.

• History of the main complaint:

  • Pain: most orthopaedic problems cause pain. History includes direct questions to ascertain the following characteristic of the pain: how long has it been present; where is it felt; does it radiate; the quality of the pain; is there associated numbness, paraesthesia or weakness; when does it occur; is there associated stiffness?

  • Deformity: indicates the alignment of a body part is abnormal.

  • Are there other bone or joint problems?

  • How does the problem affect the patient’s activities and life generally?

• Family history—enquire about possible inherited diseases but tread carefully: there may be issues of perceived guilt when speaking to a child’s parents.

• Examination: simply ‘Look, feel and move’ was advocated years ago but is not enough; you must take account of the whole patient and not just the part in question:

  • Look with the patient appropriately undressed; look for deformity by comparing the sides. Look at the skin. Look at the hands—thick skin indicates a heavy physical activity and usually means the patient has recently been able to lift heavy items.

  • Feel for tenderness but be gentle. Feel for lumps. Do not forget to palpate pulses.

  • Passively move the part to check the range of movement, but be sure not to hurt the patient—watch their face. Estimate the range of movement in degrees from the ‘anatomical position’. It is often easiest to estimate range starting from a right angle.

  • Active movement : is estimated when detecting weakness and is essential in patients with neuromuscular disease. The Medical Research Council grading of weakness is frequently used:

    • 0 = No discernible muscle contraction

    • 1 = A flicker of muscle contraction, but insufficient to move joint

    • 2 = Muscle contaction can move joint, but only if gravity is eliminated (and limb weight is counterbalanced)

    • 3 = Muscle contraction is sufficient to move against gravity

    • 4 = Functional but not normal power

    • 5 = Normal

• Investigations:

  • Bloods tests: full blood count; C-reactive protein (CRP) and erythrocyte sedimentation rate if systemic illness seems possible. In possible polyarthritis, a full rheumatological screen including estimation of the serum urate should be performed.

  • Imaging

    • X-rays are usually still the first-line imaging. They are cheap and readily accessible, and patients like to know about their x-rays. The usual model is two x-rays at right angles including nearby joints. Radiology of the skeleton in its loaded state can give more information, a “standing” radiograph of a joint will often give more information especially in an arthritic knee or deformed foot. This too applies in spinal fractures, where “stability” can be assessed by comparison of vertebral height/alignment to non-standing radiographs.

    • Ultrasound gives a dynamic view of soft tissues but bones are not imaged in useful detail. Swellings (including cysts and ganglions), ligaments, muscles and tendons are well evaluated. A dynamic picture of a joint can help in motion disorders or impingement syndromes. Ultrasound guided injections are popular.

    • Computed tomography (CT) scanning was the first effective three-dimensional (3D) imaging technique and revolutionised spinal imaging, replacing imprecise contrast studies. The speed of data acquisition has increased markedly and the radiation dose has reduced since its inception. CT scans can give detail of bones down to millimetre level. Images can be reformatted into 3D models, for example, for fractures or to plan complex anatomical reconstructions of acetabulum or spine

    • Magnetic Resonance Imaging (MRI) is increasingly used to give detail of soft tissues, bones and joints. MRI is now the gold standard where x-rays and ultrasound are inadequate. MRI is particularly useful for menisci and ligaments in the knee the spine and nerve roots exiting the spinal cord; tumours; infections; some fractures and to assess synovial thickening (for contraindications, see Ch. 5 ).

    • Isotope scanning is safe (see Ch. 5 ). Whole body bone scans can show multiple lesions, such as disseminated malignancy. Labelled white cell scanning can pinpoint suspected bone infection.

    • Positron Emission Tomography (PET) scans are being increasingly used for investigating tumours, both locally and for systemic spread.

    • Arthroscopy. Accurate diagnosis of a joint injury often requires internal inspection. Arthroscopy is often used shoulder, elbow, wrist and ankle pathology. It is less often in the hip. It is usually performed as a day case under anaesthesia., The arthroscope is connected to a camera so that a magnified view of the joint can be seen on a screen. Therapeutic arthroscopy enables abnormalities to be repaired or material removed. Most procedures take 30 to 45 minutes and recovery is usually rapid, however in more complex surgery such as hip arthroscopy this can take even longer. Arthroscopic techniques have been gradually extended to include ligament reconstruction, rotator cuff repair and cartilage repair. Similar minimal invasive technology is being employed in spinal deformity surgery, as “thoracoscopy”.

Litigation

In many parts of the world, orthopaedic and trauma surgeons have become the most likely specialists to be sued. To guard against future trouble, comprehensive contemporary notes must always be kept and it is good practice to copy any correspondence to the patient which should include a full explanation of what the problem is (as far as is known), what the management plan is and what (if any) alternative treatments are available, particularly if surgery is advocated. The risks of surgery must be fully explained and also the risk of not undergoing treatment.

Developmental Dysplasia of the Hip ( Figs 11.4 and 11.5 )

All children in developed countries are screened at birth for unstable hips using Barlow tests and seeking the Ortolani sign, and screened again at 6 to 8 weeks. Where there is doubt, or there is a family history of childhood hip problems, a breech birth, twin birth or premature delivery, ultrasound scanning should be performed. Girls are 10 times more frequently affected than boys. At this age, treatment is conservative, with a dynamic Pavlik Harness or similar device being worn for about 3 months.

Despite screening being in use for over 50 years, some children still present with a dislocated hip later than the newborn period. Under 1 year, treatment requires surgical adductor release or formal release of medial adductors, psoas and medial capsule and about 3 months in plaster. Later presentation still occurs when the child starts walking (and sometimes into the mid and late teens). The child presents with a painless Trendelenburg short leg limp, and markedly reduced hip abduction in flexion. The incidence remains stubbornly at 1:1000 births. The femoral head is found to be dislocated, with a dysplastic acetabulum, usually with a ‘false acetabulum’ on the ilium. Surgery involves stabilising the hip joint without damaging its blood supply and hence growth potential. A plaster cast (hip spica) is applied for about 8 weeks.

Perthes Disease

Boys are much more likely to develop Perthes disease and girls more often have dysplastic hips. Perthes usually manifests between 3 and 12 years. The cause is unclear but the pathology involves avascular necrosis of the femoral head ( Fig. 11.6 ). Spontaneous recovery occurs over 2 to 3 years but the final shape of the femoral head is critical in terms of later function. The outcome can be predicted from the radiological appearance. A poor outcome leads to premature hip arthritis; hip replacement is needed in 10% to 20%. Those that present before 5 to 6 years have the best outcomes.

Restricting activity (often difficult) is the mainstay of treatment if the predicted outcome is good. If predicted to be poor, containment surgery involving realigning the proximal femur can be beneficial. Valgus osteotomy and a shelf procedure for the acetabulum is indicated in children who develop coxa plana and adduction deformity.

Slipped Upper Femoral Epiphysis

In this, the femoral head slips off the neck metaphysis at the epiphyseal plate ( Fig. 11.7 ); it can occur without significant trauma but can only occur if the growth plate is unfused. The presentation may be acute, acute-on-chronic or chronic. Traumatic slips are different and occur after extreme violence.

Slipped epiphysis presents with limping and pain, often in the knee. Many cases are missed because the hip is not examined. Signs include fixed flexion, markedly limited abduction and internal rotation, and the leg is often short. Typically, these children are overweight boys and short in stature.

Upon presentation, urgent diagnosis and treatment is crucial. Loder classified cases into those who can weight bear and those who cannot. The second group are surgical emergencies. Treatment always involves surgery. The slip is stabilised by passing a pin or specialised screw across the epiphysis. One screw is usually enough but accurate placement is technically demanding and should be undertaken only by experts. In severe slips, open reduction may be needed to avoid damaging the blood supply. Consideration should be given to prophylactic pinning of the contralateral hip. There is debate over this but the authors’ view is that it should be done if the parents do not understand the potential risks, or in a premenarche girl, or in a boy whose voice has not broken.

The long-term prognosis must always be guarded as there is a marked incidence of osteoarthritis in early or mid-adulthood. Occasionally, very mild symptoms have been assumed to be growing pains and the diagnosis made only when the patient presents with an arthritic hip.

Knee Problems in Children

Pain experienced in the knee is often referred from the hip; failure to assess the hip has often led to delay in recognising a serious hip problem.

Anterior knee pain is common in children between 11 and 16 years. Full assessment needs to be made but most eventually become asymptomatic without treatment.

Osgood–Schlatter and Larsen diseases both affect the tibial insertion and origin of the patellar ligament. The natural history is towards spontaneous resolution but can take 18 to 24 months. Both diseases cause activity related pain but usually resolve spontaneously. Placing the limb in a plaster cast for a month or so often speeds recovery. Osgood-Schlatter’s disease often leaves a permanently prominent tubercle.

Osteochondritis dissecans is where a section of articular cartilage dissects from its femoral condyle, usually affecting the lateral side of the medial condyle. Pain and instability are typical symptoms; an intercondylar x-ray demonstrates the lesion well and MRI can be helpful in determining treatment. Many spontaneously improve but unstable lesions need to be pinned and sometimes bone grafted.

Discoid lateral meniscus —rather than being semilunar, the lateral meniscus is solid and devoid of its central recess. The condition presents as pain in the outer side of the knee, instability and clicking or clunking. Conservative management should be followed where possible. The surgical option is to ‘re-sculpture’ it to resemble a normal lateral meniscus.

Club Foot (Talipes Equino-Varus)

About 1:1000 children is born with club foot ( Fig. 11.8 ). For many years, early radical surgery was standard treatment. In this, all the ligaments around the joints of the hind-foot were incised, and the Achilles tendon and the flexor tendons lengthened. Nowadays Ponsetti’s nonoperative method of manipulating and splinting the foot is usually successful. Occasionally percutaneous division of the Achilles tendon is needed and can be done in the neonatal period under local anaesthesia. The results are excellent and these patients go on to live a normal life. The condition is often picked up during a prenatal maternal ultrasound scan and the parents can be reassured about the outcome, provided more serious conditions, such as spina bifida are absent.

Pes Cavus is where the metatarsal heads lie below the heel in a neutral foot position. There is a high arch, a varus heel and usually wasting of small foot muscles. Colman’s block test helps to distinguish whether the hind foot is fixed or mobile. Pes cavus can be associated with polio, hereditary sensory and motor neuropathy (Charcot–Marie–Tooth disease), spina bifida and other spinal conditions, such as diastomatomyelia. Treatment involves orthoses or reconstructive surgery.

Limb bud failures are relatively common and account for a large number of congenital deformities, such as tibial or fibular dysplasia, proximal focal deficiency and radial club hand, among others.

Tarsal coalition is an example of failure of separation ( Fig. 11.9 ). The common types are talocalcaneal and calcaneonavicular. These coalitions can be fibrous, cartilaginous and most usually bony. They cause the child to complain of a painful foot. Examination confirms absence of hindfoot movement often with normal ankle movement. The treatment is either excision of the bar (if it is small) or surgical fusion of the subtalar and midfoot joint.

Various eponymous syndromes are common in a children’s orthopaedic clinic. It is worth remembering that learning difficulties plus two skeletal abnormalities strongly suggests a chromosomal problem.

Primary bone tumours in children are rare although Ewing sarcoma and osteosarcoma must be considered during teenage years. Reticuloses including leukaemia can present with skeletal pain. Bone cysts and remnants of ossification errors, such as cortical fibromas are often seen incidentally on x-ray. They are usually asymptomatic and need no treatment.