Chapter 6 Limb problems
6.1 Introduction
Diseases of the arterial, venous, lymphatic, neurological and musculoskeletal systems of the limbs produce specific symptoms requiring special examination techniques for each system. These techniques are discussed in more detail under the clinical problems that arise from diseases of the bones, joints, vessels, nerves and other structures of the upper and lower limbs. It is essential to compare both sides during examination. In all patients it should be routine to test the urine for diabetes, a common aetiological factor in diseases affecting the lower limb.
Arterial circulation
Examination
2 Palpation
The leg with arterial ischaemia is cool, a sign that is emphasised by comparison with the other side. Skin temperature is best appreciated by palpation using the sensitive thin skin over the dorsum of the middle phalanges (Fig 6.1). Diminished capillary return is present if more than two seconds is taken for colour to return after finger pressure is applied to the big toe.
The peripheral pulses in the affected limb are diminished or absent. The dorsalis pedis artery runs from a point midway between the malleoli to the space between the first and second metatarsal bones and is just lateral to the extensor hallucis longus on the forefoot. The dorsalis pedis may be absent in 5–10% of the population and its place may be taken by a branch of the peroneal artery. The pulse will then be felt more laterally. The posterior tibial artery is found in the soft tissue groove below and behind the medial malleolus, halfway between it and the Achilles tendon. The popliteal pulse is the most difficult to find and is best palpated in the lower popliteal fossa with the knee passively flexed. Beware that an easily felt popliteal pulse is often a sign of a pathologically enlarged popliteal artery. The femoral pulse is usually easily palpable in the groin at the midinguinal point (Fig 6.2). The effects of exercise on the appearance of the limb and on distal pulses should be assessed. In moderately severe disease, palpable pulses may disappear on exercise. It is also important to remember the surface landmarks for the various pulses in situations of ‘extremis’ when pulses may be very weak. The abdominal aorta and iliac vessels should also be examined.
Venous circulation
Examination
1 Inspection
The legs are inspected for visible varices involving the long and short saphenous venous systems. A small proportion will also show evidence of chronic venous insufficiency. In patients with chronic venous insufficiency, inspection reveals visible subcutaneous or varicose veins together with bluish-red patches of minute intradermal vessels, known as ankle or malleolar flares or venous stars. The skin in the region of the lower medial third of the leg (gaiter area) shows the signs of venous hypertension: apart from malleolar flares these are: the brown pigmentation of extravasated haemosiderin; dry eczema with a ‘psoriatic’ skin reaction; sclerosing periangiitis with subcutaneous induration; and fibrosis and ulceration. With chronic ulceration and fibrosis, the leg takes the permanent shape of an inverted bottle; contracture may be sufficient to produce an equinus deformity of the ankle and a characteristic waddling gait.
Neurological system
This system is discussed in more detail in Chapter 5. The following is a brief summary relevant to limb examination.
Examination
1 Motor nerve function
Muscle power is tested by active movement against resistance and graded from 0 to 5 therefore (see Tables 5.1 and 5.2):
4 Gait
Bilateral abductor dysfunction or weakness may result in a waddling gait. Waddling gait may also be seen in obese patients, those with bilateral congenital dislocation of the hips and in patients with muscular dystrophy affecting the trunk and pelvic girdle muscles. In those with dystrophy there is often a need to use their hands to climb up their own thighs when getting up from lying down (‘Gower sign’). A short leg results in a limp that can easily be recognised. A stiff knee and hip results in the leg often being swung out (circumducted) as it is brought forward to take a step (using pelvic rotation to advance it rather than hip or knee flexion). In the hemiplegic gait the foot is dragged and the toes are scraped along the ground. With each step the affected limb is circumducted at the hip and swung out and the pelvis on that side tilts forward (see also Ch 5).
Musculoskeletal locomotor system
Examination
2 Palpation
There is a temptation to commence this part of the process by poking the painful area — something best avoided until closer to the end of the examination. Signs of heat, tenderness, swelling or oedema are noted by a hand laid gently onto the affected limb segment. Any localised swelling is noted and its physical characteristics recorded. In the supine patient, one leg may appear to be shorter than the other (apparent shortening — measured from the malleolus to a fixed point on the trunk such as the umbilicus). True shortening of the limb is established by comparing the distance on both sides from the tip of the medial malleolus to a fixed point on the bony pelvis — the anterior superior iliac spine. Accurate measurement of true shortening requires that the joints of both limbs be in an identical position, with the pelvis square to the sagittal plane and both iliac spines at right angles to the line of the spine (Fig 6.3). A fixed abduction or adduction deformity of one limb can cause apparent lengthening or shortening of that side — true shortening is checked after placing the opposite limb in a similar position of abduction or adduction. True shortening is often due to hip disease. The level can be simply and rapidly demonstrated by the disparity in span shown on bilateral palpation of the hip joint — placing the thumb on the anterior superior iliac spine and the middle finger on the greater trochanter and measuring by eye any disparity in distance between these digits on each side.
6.2 Bony lumps
The usual causes of bony lumps are injuries, benign or malignant neoplasms and malformation and inflammatory lesions (Fig 6.4). A history of injury suggests reparative bony callus as a cause. It must be remembered that fractures may occur through a pathological focal lesion and sometimes normal bones fracture with no history of injury. Primary bone neoplasms are much less common than are secondary tumours but are more common as a cause of a painfully enlarging mass in the bone. Secondaries in the bone more often present with pain alone or as a spontaneous or pathological fracture. Infections, soft tissue sarcoma and benign developmental skeletal abnormalities can also present as a painful bony swelling. Bony swellings near a joint can be mistaken for an inflammatory monoarticular arthritis. In some instances it may be difficult to tell whether a limb swelling is arising from the bone or from adjacent soft tissues. Normally, when a soft tissue swelling arises primarily from bone, it involves all layers and radiates more or less symmetrically from the bone outwards. The adjacent joints are usually normal.
The most common causes of localised bony swelling in patients aged under 25 years are fracture, callus formation, acute osteomyelitis and osteosarcoma; aged from 25 to 50 years, giant cell tumour, fibrosarcoma and chondrosarcoma; aged over 50 years, metastatic bone disease, localised myeloma and fibrosarcoma (Table 6.1). Nearly all benign tumours occur in the young and stop growing when growth is completed, so diagnosis of these is easy to make in most cases. Large tumours are not necessarily malignant, although recent increase in size does suggest the possibility of malignant change. The main features that suggest malignancy are pain, warmth and tenderness with cortical destruction on X-ray and calcification that extends into the soft tissues. The most common benign tumours are exostoses (bony hard lesions fixed to the bone found near the lower end of the femur and upper end of the tibia), osteomas (flat bony swellings frequently found on the forehead) and chondromas. Chondromas may grow in or out from the surface of the bone. Enchondroma within the bone may present as a fusiform swelling of the bone. Biopsy is essential when malignancy is suggested clinically and histological confirmation of malignancy is essential prior to radical surgery.
Age group (years) | Lesion |
---|---|
<25 | Fracture, callus formation, acute osteomyelitis, osteosarcoma |
25–50 | Giant cell tumour, fibrosarcoma, chrondrosarcoma |
>50 | Metastatic bone disease, myeloma, fibrosarcoma |
History, physical examination and radiology
1 Callus formation
The most common cause of a bony tumour is exuberant callus formation at a fracture site. In most cases there is a history of injury, but sometimes a palpable callus is felt to develop after some weeks of pain from a spontaneous fracture. It is the latter group where diagnosis may be a problem. The most common sites are rib after paroxysmal coughing, second metatarsal bone after a long walk (‘March fracture’) and the upper end of the tibia (‘Recruit’s fracture’). Examination reveals a relatively nontender fusiform enlargement of the bone. The diagnosis is, as a rule, made easily on X-ray.
2 Acute osteomyelitis
X-rays show a central area of rarefaction, surrounding sclerosis of bone and deposition of subperiosteal new bone. Within about two weeks of the onset of acute osteomyelitis, an area of sclerotic dead bone (sequestrum) will appear in the central area of rarefaction (Fig 6.5). However, X-rays may not show any abnormal features in the first few days of the disease process.
3 Osteosarcoma
Most cases of osteosarcoma (osteogenic sarcoma) occur before the age of 25 years. Occasionally osteosarcoma occurs in the aged patient as a complication of Paget’s disease of bone. Osteosarcomas may also arise in bone that has been irradiated for other reasons. A painful bony lump is the predominant symptom. The onset is usually gradual, with a progressive increase in pain, a variable degree of swelling, local heat, venous engorgement and tenderness. Most sarcomas develop in the medullary cavity near the metaphysis of a major long bone; half lie in the region of the knee. A history of previous trauma may be given, that is, either incidental to the underlying process or has precipitated a pathological fracture. Palpation usually reveals a swelling close to the knee without detectable joint disease and with free joint movement.
7 Metastatic carcinoma
Secondaries are a relatively uncommon cause of painful bony swelling. However, they are the most common bone tumour in patients over the age of 40. The major primary sites that commonly metastasise to bone include a lung, breast, prostate, kidney and thyroid. The vast majority of metastases in bone present with bone pain rather than swelling and a minority present with spontaneous fracture. Kidney and thyroid secondaries are the ones most likely to produce swelling as well as pain. The patient often has a past history of the primary tumour and its treatment, such as mastectomy for carcinoma of the breast. Sometimes symptoms of the primary tumour and its metastases may be synchronous. Approximately 10% of patients with cancer present with bony metastases as the first sign of disease. Some metastases, such as from the kidney, may be so vascular that they resemble an aneurysm. The common sites of metastasis are areas of bone marrow formation such as skull, clavicle, rib, vertebrae and upper femur and humerus. Local radiotherapy will often relieve bone pain. Lesions in long bones resulting in extensive cortical destruction and pain may often require an orthopaedic opinion regarding prophylactic surgery in order to prevent fracture.
Diagnostic and treatment plans
A benign tumour remains localised and on X-ray has a well-defined edge. In contrast, a malignant tumour has the potential to metastasise, growth is rapid and its edge is often ill defined. The features that suggest malignancy on X-ray are cortical destruction and calcification extending into the soft tissues (Fig 6.6).
One of the main management problems is to establish the diagnosis of osteosarcoma and to exclude the differential diagnoses of subacute osteomyelitis or a benign neoplasm. It may also be difficult to distinguish neoplasia from the various cystic diseases of bone. Biopsy and histology generally provide the definitive diagnosis but must be correlated with the other clinical and radiological findings. If the diagnosis remains in doubt, conservative treatment may be started, with careful clinical and radiological observation for a period of time before radical surgery is recommended. With a definitive diagnosis of osteosarcoma surgery combined with chemotherapy improves survival. Limb salvage surgery combined with adjuvant chemotherapy, in the right setting, may provide results that are at least comparable to those with amputation and adjuvant chemotherapy. The chemotherapy is most often administered preoperatively, with the pathologist being able to examine the specimen postoperatively and comment on a better outcome should there be a higher degree of necrosis (preferably greater than 95%). Other malignant tumours may also often require limb ablation surgery.
6.3 Musculotendinous lumps
Muscle rupture and degeneration often occur at the junction of the muscle with its tendon or aponeurosis. Sometimes the injury occurs within a tendon widely distant from the parent muscle and presents as a focal lump in the tendon or a spontaneous rupture of the tendon. Symptoms and signs will then be mainly concerned with the tendon; disabilities and deformities induced by active contraction will again be diagnostic.
Benign and malignant neoplasms within and near muscles have their physical characteristics distorted by this proximity — important signs are limited mobility or fixation of the lump when the muscle is tensed and contracted. As well as becoming less mobile, swellings may change in shape and size on muscle contraction. The lump may disappear or become more difficult to feel, suggesting that the lump is within the muscle (Fig 6.7). On the other hand, the lump may occasionally become prominent only when adjacent muscles contract, suggesting extrusion from between muscle bundles or through a defect in the fascial envelope of the muscle. The patient can be asked to contract the muscle isometrically or isotonically to elicit these points or the muscle can be put on the stretch by the examiner, separating origin and insertion by passive joint movements.
Tendinous swellings
Clinical features, diagnostic and treatment plans
Muscle swellings
1 Muscle rupture
Ruptured long head of biceps brachii tendon. The patient is usually over 50 years; however, the injury may also occur in an athlete performing a large amount of weight training such as bench-press activities. Rupture in the older age group is usually secondary to degenerative weakness and the long head, with its complex intracapsular course over the humeral head, is particularly at risk. The patient may have felt something snap while lifting or flexing the elbow but may not have noted a precipitating event. The clinical picture is unmistakable (Fig 6.8). The belly of the muscle is distorted, looks lower than the other side, does not tighten properly on contraction and is round or semicircular in shape rather than fusiform and ovoid. Shoulder and elbow movements are free and painless — apart from evidence of degenerative joint disease or, occasionally, rheumatoid arthritis. In the younger athlete, sometimes pain may be reproduced by passive stretching of the biceps (Speed’s test) or resisted active contraction (Yergason’s test). While active treatment in either case is rarely required, there is an increasing tendency to repair proximal ruptures in the younger, high-performance athlete. Occasionally the biceps are avulsed from their distal (radial) insertion — this is usually a more acute and painful injury from lifting heavy weights and the muscle belly retracts to a higher position and sometimes requires repair to the bicipital tuberosity in order to preserve full motor power in the younger person.
Supraspinatus (rotator cuff) rupture. This can accompany shoulder injuries such as dislocation or lifting strains. A degenerative rotator cuff in patients over 45 years is more prone to rupture. Active abduction of the shoulder is impaired or not possible, despite an actively contracting deltoid. The shoulder hunches laterally on attempts by the patient to initiate abduction. If the arm is passively elevated through the painful arc, it can be maintained above the head by action of deltoid and the remaining muscles (see Ch 6.4). The treatment of this pathology should include treatment of the tendinopathy and treatment of the associated bony abnormalities. The lateral edge of the acromion may impinge on the rotator cuff during active abduction of the shoulder. Surgical repair of complete rupture is the standard in young patients. In older patients a corticosteroid injection into the subacromial space combined with an exercise program to strengthen the rotator cuff and the periscapular muscles may be all that is required. Surgery in older patients is mainly for the pain-relief associated with alleviating impingement rather than gains in muscle power.
Sternomastoid ‘tumour’. Tearing of sternomastoid muscle fibres can occur in infants, causing a sternomastoid muscle ‘tumour’ with muscle spasm and torticollis (wry neck). The wry neck is seldom visible at birth. Usually within a week or two the parents notice a lump at the lower end of the sternomastoid muscle with the head being held asymmetrically and persistently rotated to one side. As the child spends more time on the one side the face and occiput become more flattened on that side. Treatment is predominantly conservative, with gentle stretching exercises supervised by a paediatric physiotherapist. It is prudent to ask for an orthopaedic opinion in order to exclude congenital cervical vertebral anomalies. The syndrome can also occur in older children and adults. In older children inflammatory conditions of surrounding soft tissue structures, optical disorders and rotatory subluxation of the C1 vertebra on the C2 vertebra are the most common casues. In adults it is more commonly due to a nearby inflammatory lymph node swelling.
2 Intramuscular haematoma
This presents as a painful, tender, firm lump with indistinct edges within a muscle. It often follows an injury during a movement with the muscle under heavy load or after localised contusion. There is associated muscle pain and weakness. Common sites are the thigh, involving quadriceps femoris or hamstring muscles in footballers (‘cork leg’). Treatment is by a brief period of rest; local ice packs and compression, followed by active exercises (Ch 13).
4 Benign or malignant intramuscular neoplasms
‘Desmoid’ tumour (Paget’s tumour). This is a less common form of locally aggressive tumour and usually occurs in the muscles of the anterior abdominal wall. It presents as a firm lump within the rectus muscle of the lower abdomen, often in multiparous women. It requires wide local excision to avoid recurrence (Ch 8.3).
Malignant muscle tumours (fibrosarcoma, rhabdomyosarcoma). Fibrosarcoma is the most common mesodermal tumour of muscle and presents as a painless intramuscular lump. Distal spread occurs late, the lump may be firm or soft and may be vascular and even demonstrate a soft bruit. It can be difficult to distinguish from a benign haematoma without biopsy. CT scanning and more recently MRI are helpful in the diagnosis and delineation of the extent of suspected tumour masses. The lesions are most common on the limbs and may be close to or attached to bone. Smaller tumours present as completely circumscribed and, as they enlarge, tend to become diffusely infiltrative. Other sarcomas such as rhabdomyosarcoma are more malignant and spread locally and systemically at an early stage. Removal of the tumour is necessary for local control. Treatment requires wide local excision after exploration and biopsy. As local spread tends to be within the muscle bundle, excision should encompass the whole muscle involved, from origin to insertion. Consideration needs to be given to excising the whole compartment in which the muscle is found. Chemotherapy and radiotherapy are often also required. Multimodal therapy involving limb salvage surgery combined with adjuvant chemotherapy and radiotherapy may provide survival rates comparable to amputation and chemotherapy, while preserving a functioning limb.
5 Less common causes
Myositis ossificans. Traumatic myositis ossificans occurs after severe soft tissue or bony injury with lifting and disruption of the periosteum at the site of attachment of muscles and ligaments to bone. Calcification and ossification occur within the soft tissue haematoma. Common sites are around the elbow and knee — within the brachialis, deltoid or quadriceps femoris after fractures and dislocations or tendinous avulsions. Patients present with hard, bony lumps, usually attached to bone at the site of tendinous insertions or in continuity with the callus of a fracture. Initially the swelling may have sharp edges and be painful and tender. Later the swelling’s edges become rounded, tenderness diminishes and the lump may regain a degree of mobility on the underlying bone. Joint stiffness is common, but there are no signs of inflammation. Differentiation from an intrinsic bony swelling can be difficult (Ch 6.2). With a primary swelling of bone, the muscles are usually more freely mobile over the lesion. In myositis, muscle function is impaired and the swelling is in continuity with the muscle.